GAN 大功率器件车载 DC-DC 转换器问题

In this paper, a step-down converter chip with high conversion efficiency is designed based on silicon-based gallium nitride heterogeneous integration technology. Among them, the GaN HEMT uses EPC2036 FET bare die, the control circuit adopts the TSMC 0.25um BCD process for research and design, and the pulse width modulation and voltage mode control are used to design the overall system. The simulation results show that the switching frequency of the buck converter is 1MHz, the input voltage is 48V, the output voltage is 3.3V~5V, the output power is 3.6W at full load, and the maximum conversion efficiency is 93.7% when the output voltage is 5V. The chip design technology is suitable for miniaturized vehicle power converter and other applications.

This paper assesses the efficiency of DC-DC buck converters utilizing both MOSFET and GaN-FET technology. An analysis is conducted on single-phase switched capacitor buck converter equipped with GaN FETs, highlighting its capability to operate at higher frequencies due to the rapid switching speeds of GaN FETs. This feature results in a decreased size of passive components in comparison to traditional buck converters. Additionally, the specifications for the inductor are also examined. To demonstrate the advantages of GaN FETs over MOSFETs in DC-DC converters, the performance of the GaN-FET based converter is compared with that of a traditional MOSFET-based converter. Key performance metrics evaluated includes output voltage, inductor current ripple, voltage stresses across semiconductor devices, power losses, and overall efficiency. The results indicate that the GaN-FET based converter achieves a lower output voltage at higher duty cycles, reducing losses associated with small duty cycles. Additionally, the proposed converter demonstrates superior performance across all evaluated parameters, reinforcing the efficiency benefits of GaN-FET technology in DC-DC buck converters.

The conventional resonant inductor–inductor–capacitor (L2C) DC–DC converters have the major drawbacks of poor regulation, improper current sharing, load current ripples, conduction losses, and limiting the power levels to operate at higher loads for electric vehicle (EV) charging systems. To address the issues of the L2C converter, this paper proposes an interleaved inductor–inductor–capacitor (iL2C) full-bridge (FB) DC–DC converter as an EV charger with wide input voltage conditions. It comprises two L2C converters operating in parallel on the primary side with 8-GaN switches and maintains the single rectifier circuit on the secondary side as common. Further, it introduces the hybrid control strategy called variable frequency + phase shift modulation (VFPSM) technique for iL2C with a constant voltage charging mode operation. The design requirements, modeling, dynamic responses, and operation of an iL2C converter with a controller are discussed. The analysis of the proposed concept designed and simulated with an input voltage of 400 Vin at a load voltage of 48 V0 presented at different load conditions, i.e., full load (3.3 kW), half load (1.65 kW), and light load (330 W). The dynamic performances of the converter during line and load regulations are presented at assorted input voltages. In addition, to analyze the controller and converter performance, the concept was validated experimentally for wide input voltage applications of 300–500 Vin with a desired output of 48 V0 at full load condition, i.e., 3.3 kW and the practical efficiency of the iL2C converter was 98.2% at full load.

This paper discusses the analysis and design of a multi-port DC-DC converter using Gallium Nitride transistors for a 350V bipolar DC grid application, which could be used as the first stage to interconnect a 350V bipolar DC grid and two electric vehicle batteries. The multi-port DC-DC converter is designed with a three-level neutral-point-clamped triple-activebridge topology. The converter's parameters are selected on the basis of its performance characteristic and system specifications. Moreover, a simulation model is built to analyze the design. In the end, a prototype converter is built and the preliminary experimental results of it are shown and discussed.

In this research, an innovative electric vehicle (EV) charger is designed and presented for xEV charging stations. The key feature of our system is a scalable, interleaved inductor–inductor–capacitor (iL2C) DC-DC converter operation. The proposed system employs two parallel L2C converters with 8-GaN switches on the primary side and a shared rectifier circuit on the secondary side. This configuration not only amplifies the resonant tank internal currents and losses generated by the switches but also improves current sharing. A novel closed-loop technique is proposed with a constant-voltage method of operation, along with a hybrid control scheme of variable frequency + phase shift modulation (VFPSM). To examine the controller and converter’s performance, an experimental demonstration is conducted under varying load conditions, including full load, half load, and light load, where the source voltage and load voltage are maintained at constant levels of 400 Vin and 48 V0, respectively. Furthermore, line regulation is conducted and verified to accommodate a broad input voltage range of 300 Vin–500 Vin and 500 Vin–300 Vin while maintaining an output voltage of 48 V0 at 3.3 kW, 1.65 kW, and 0.33 kW with a peak efficiency of 98.2%.

Bootstrap capacitor in FET gate driver plays an important role in the transient performance of the half bridge configured synchronous buck DC‐DC converter especially in the top switch. In this paper, a new bootstrap capacitor based GaN‐FET driver is proposed. This new GaN‐FET driver is tested in a synchronous buck converter for performance verification like dvdt immunity, transient response, and voltage ringing. A comparison study with the existing LM5113 (Texas Instrument)–based driver for GaN‐FET and IR2110‐based Si‐MOSFET driver on a DC‐DC converter is carried out to show the performance improvement using the proposed GaN‐FET driver. The simulation study is performed on spice‐based NI‐Multisim 14.1. Finally, the designed GaN‐FET driver is tested on a 60‐W synchronous buck DC‐DC converter in open‐loop and closed‐loop configuration.

Bootstrap capacitor in FET gate driver plays an important role for measuring transient performance of half bridge configuration especially in the top switch. In this paper bootstrap capacitor design for GaN-FET driver is discussed. Based on the design a new gate driver for GaN-FET is proposed for improving dv/dt immunity. The performance of the proposed GaN driver is compared with existing LM5113 (Texas Instrument) based driver and IR2110 based MOSFET driver. The modelling is carried out in Spice based Multisim 14.1 simulation environment. The bootstrap capacitor-based GaN driver is tested on 60W synchronous buck DC-DC converter.

This paper aims to develop a flexible power management approach to interconnect multiple energy resources based on an isolated, monolithic multiport DC-DC power converter. Specifically, a high efficiency, ultra-compact Quad-Active-Bridge (QAB) DC-DC converter is proposed to interconnect photovoltaic (PV), battery energy storage (BES), electric vehicle (EV) charging/discharging, and a distribution grid. Fast-switching Gallium Nitride (GaN) high-electron-mobility transistors (HEMTs) are employed to achieve higher energy efficiency and power density. To meet the high voltage requirements on the DC grid port, a three-level active-neutral-point-clamped (ANPC) bridge based on 650V GaN HEMTs is developed. To provide galvanic isolation among different power ports, a high-frequency, multi-winding planar magnetic transformer is utilized to couple different power ports for flexible power management. The control and efficiency at four operating modes of the QAB converter are investigated for various weather conditions, and electro-thermal simulations for the QAB converter, including the planar transformer, are carried out in PLECS and Ansys software. Moreover, a 15-kW GaN HEMT based QAB DC-DC converter prototype is implemented for experimental verification.

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This article presents an optimization strategy for enhancing the efficiency and power density of a GaN-based dc–dc converter, tailored for different applications with a wide input voltage range regulation. The optimization employs air-core inductors and implements a variable switching frequency modulation method to enable zero voltage switching turn-on for GaN transistors, facilitating greater flexibility in frequency adjustment and improved thermal management. Additionally, a specialized thermal model is introduced for the interleaved Buck-Boost GaN transistor-based dc–dc converter, accounting for the presence of a natural convection heatsink. In the conclusion, theoretical discussions transition to practical implementation through the testing of a laboratory prototype. This prototype achieves high efficiency (around 99%), along with power densities of >17.5 kW/L and 6 kW/kg when equipped with a natural convection (without airflow) heatsink. It features a wide input voltage range (110–450 V), a constant output voltage of 350 V, variable switching frequency (18–304 kHz) and supports up to 9 kW output power.

This study presents a hard-switching full-bridge DC-DC converter with synchronous rectification based on Gallium Nitride (GaN) transistors to evaluate the advantages of GaN devices in power supplies. In comparison to traditional silicon-based devices, GaN transistors are utilized in both the primary and secondary stages of the converter, exploiting GaN’s lower on-resistance to enhance performance. The converter operates at a switching frequency of 300 kHz, with an input voltage range of 36 V to 75 V, delivering an output of 28 V/42 A. Experimental results show that the GaN-based converter achieves an output power of 1176 W within standard half-brick package dimensions. The measured peak efficiency is 97.1%, and the power density reaches 430 W/in3. These findings demonstrate that GaN-based converters offer superior efficiency and power density compared to conventional silicon-based designs, making them highly suitable for aerospace, automotive, and communication power supplies.

In conventional electric vehicles, the on-board charger and wireless power transfer operate as two separate charging systems, which can lead to redundancy and increased costs. To enhance the integration of electric vehicle (EV) battery charging systems, this paper proposes a novel DC-DC topology integrating a wireless power transfer (WPT) and a CLLC resonant converter. By sharing the receiver coil, compensation capacitor and full-bridge rectifier between the two subsystems, the proposed design achieves high power density while significantly reducing the system cost. Instead of a transformer in the CLLC converter, a strong coupling mechanism is used, and the secondary coil of the strong coupling mechanism can be loosely coupled to the transmitter coil of the WPT system and used as the receiver coil. The integrated DC-DC topology has a large difference in leakage inductance between the receiver coil in CLLC mode and WPT mode due to the difference in coupling coefficients, which requires compensation capacitors with different capacitance values, so switched capacitor regulation of capacitance values is proposed to achieve the optimal operation of WPT and CLLC systems. This paper describes the integrated DC-DC topology, the operating principles in different modes, and the design of a novel integrated magnetic coupling mechanism, and finally verifies its feasibility through experiments.

This paper analyzes half-bridge DC-DC buck converter topology operating in buck mode using Gallium Nitride (GaN) transistors for Electric Vehicles (EVs) application. The LTspice-based simulation model is developed for the buck converter with parasitic elements to evaluate performance efficiency for varying load. The impact of parasitic passives (resistance, inductance, and capacitance) such as ringing by parasitic inductance on GaN transistor operation are also explored. Effects on performance efficiency has been carried out with and without including the parasitic elements in the simulations to evaluate the importance of modeling with parasitics. Performance efficiency evaluation results are also bench-marked against the results of the EPC 9162 demonstration board working as a bi-directional buck converter.

Double-input converter is recognized as being the critical part of power conversion system of hybrid electric vehicle (HEV). As the power sources, such as battery and solar panel, have unregulated low voltage, this application requires a high gain double-input DC/DC converter. In this paper, a three-port three-level converter composed of Buck-Boost-Half-Bridge (BBHB) modules using gallium nitride (GaN) switch is proposed for HEV application. The proposed converter can supply the load in absence of PV or battery. The converter take the advantage of active clamp configuration, in terms of providing soft-switching performance and simple control technique, to enhance both power density and efficiency. To address the main challenge of employing GaN switches, their capability to withstand high voltage, the BBHB modules are connected in the stacked configuration. Finally, a 1 kW, 50 kHz prototype is implemented to validate the proposed concept.

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Cryogenic power electronics has been regarded as the next step to improve the system efficiency and power density. Moreover, some semiconductors have been reported to have improved performances under cryogenic temperatures. Bi-directional DC/DC converter is often required to interface between different energy sources. In this article, the cryogenic performances of the Cascode GaN based bi-directional DC/DC converter are reported. The individual components performances are characterized under low temperatures, including Cascode GaN FET, gate driver, magnetic component, and capacitor. A significant conduction loss reduction is expected due to the reduction of on-state resistance under low temperatures. The XFlux core are implemented as the magnetic components due to its stable core loss and permeability performances. The polypropylene film capacitor is selected for both the filer capacitor and resonant capacitor owning to its stable capacitance and dissipation factor performances under low temepratures. Then, a 400 W experimental prototype was tested. The results demonstrate that the evaluated Cascode GaN based converter has stable efficiency performance under low temperatures. Efficiency improvement is observed under light load operation condition. Overall, the Cascode GaN based resonant converter would be a feasible solution for cryogenic applications.

This paper discusses the potential to decrease the response time of a DC–DC converter through the substitution of Si transistors with GaN transistors and the implementation of digital control techniques. This paper introduces an improved methodology for designing digital voltage controllers by analyzing discretization delays and subsequently implementing a modified analog controller design method. The theoretical analysis was verified using an experimental prototype of a 100 W 48 V to 12 V GaN-based DC–DC converter. A digital controller that allows a 50 kHz bandwidth to be achieved based on an STM32G4 microcontroller was developed, and the design of the controller is discussed in detail. The converter was operated with a 500 kHz switching frequency using a 6 µH inductor and a 20 µF ceramic capacitor output filter. Although the digital control introduced a 1.2 µs delay, a converter response time equal to 40 µs was achieved. Simulation models were created and their results were verified via comparisons with experimental results obtained with an AP310 frequency response analyzer.

The distinctive characteristics, such as fast switching and higher power density of gallium nitride (GaN) power semiconductor devices, are fascinating for power electronic applications. That makes it suitable for achieving high efficiency at high switching frequency operation. However, the control at higher switching frequency operation and evaluation of dead time is pivotal to achieving it. This article presents the GaN-based non-inverting buck-boost (NIBB) dc–dc converter for high-frequency and high-efficiency operation. The feedback control was designed and implemented using FPGA for the operation of the converter at a switching frequency of 500 and 800 kHz under different operating load conditions. Furthermore, the dead time evaluated corresponds to switching frequencies and load conditions. The PCB layout was designed to develop an experimental prototype of the NIBB converter developed using the LMG5200 GaN half-bridge chip (80 V, 10 A). The converter is tested for the 48–48 V operation considering the LED applications with a one-to-one voltage ratio and a Pareto front curve is given for the 250 kHz, 500 kHz, 800 kHz, and 1 MHz switching frequency.

This article provides a comprehensive experience of thermal management considerations about GaN-based converters. It elucidates the thermal properties commonly found in transistor datasheets, encompassing parameters like transient thermal impedances and thermal resistances. The discussion extends to the thermal design strategy for top-side cooling, covering aspects such as Thermal Interface Material (TIM) and heatsink selection. Additionally, the article introduces a thermal model specifically for an interleaved Buck-Boost GaN transistor-based dc-dc converter, considering the scenario with a heatsink. This holistic examination contributes valuable insights to the field of thermal management in GaN-based converter designs. In the conclusive phase, the laboratory prototype of the interleaved GaN-based converter was subjected to testing at up to 5 kWoutput power and 300 kHz switching frequency, employing two distinct TIMs. The experimental results obtained from this comparison are thoroughly analyzed and presented in the article.

DAB (Dual-active-bridge) and CLLC are two common isolated bidirectional DC/DC converters, but they are limited by soft switching and gain adjustment range respectively, and cannot meet the requirements of high-efficiency, bidirectional, wide range, and full power transmission of products. Boost-SRC is a combination of the advantages of the two, using vary frequency and phase-shift control method, meet the soft switch, the higher gain and suitable for wide output voltage regulation applications. In this paper, firstly, the working principle of the topology is introduced, and the time domain analysis is carried out based on the phase-plane analysis method. Secondly, the general engineering design steps and system control methods are given. Finally, a 6. 6kW bidirectional DC/DC prototype was built using Navitas Nano-Toll packaging GaN devices, and the charge and discharge efficiency curves were measured, the highest switching frequency up to 900khz, which verified the feasibility of GaN devices application in high-power vehicle products.

Automotive-grade GaN power switches have recently been made available in the market from a growing number of semiconductor suppliers. The exploitation of this technology enables the development of very efficient power converters operating at much higher switching frequencies with respect to components implemented with silicon power devices. Thus, a new generation of automotive power components with an increased power density is expected to replace silicon-based products in the development of higher-performance electric and hybrid vehicles. 650 V GaN-on-silicon power switches are particularly suitable for the development of 3–7 kW on-board battery chargers (OBCs) for electric cars and motorcycles with a 400 V nominal voltage battery pack. This paper describes the design and implementation of a 6.6 kW OBC for electric vehicles using automotive-grade, 650 V, 25 mΩ, discrete GaN switches. The OBC allows bi-directional power flow, since it is composed of a bridgeless, interleaved, totem-pole PFC AC/DC active front end, followed by a dual active bridge (DAB) DC-DC converter. The OBC can operate from a single-phase 90–264 Vrms AC grid to a 200–450 V high-voltage (HV) battery and also integrates an auxiliary 1 kW DC-DC converter to connect the HV battery to the 12 V battery of the vehicle. The auxiliary DC-DC converter is a center-tapped phase-shifted full-bridge (PSFB) converter with synchronous rectification. At the low-voltage side of the auxiliary converter, 100 V GaN power switches are used. The entire OBC is liquid-cooled. The first prototype of the OBC exhibited a 96% efficiency and 2.2 kW/L power density (including the cooling system) at a 60 °C ambient temperature.

This article proposes an integrated on-board charger (IOBC) for electric vehicles (EVs) based on an isolated three-port dc–dc converter. The proposed architecture integrates the on-board charger (OBC) and the auxiliary power module (APM) in a single multiport converter, offering a low component count. The proposed converter is capable of charging high-voltage (HV) and low-voltage (LV) batteries simultaneously, over the entire battery voltage ranges. A three-winding transformer is used to provide galvanic isolation between the converter ports and consequently, power flow is coupled among the three ports. In this article, a boundary condition is derived for the first time and a novel modulation scheme is proposed to regulate the power flow at the HV and LV ports independently, utilizing the converter’s 3-degrees-of-freedom (3-DOF). Hence, charging of the HV and LV batteries can be realized similar to dual-active-bridge (DAB) and phase-shifted full-bridge (PSFB) converter, respectively. Results show that all converter semiconductor devices operate with zero-voltage-switching (ZVS) over wide power and voltage range without the need for additional resonant components, due to the proposed 3-DOF selection scheme. A 3.5-kW hardware prototype of the proposed converter is built and tested and key experimental results are presented to verify the converter’s theoretical analysis and ZVS operation.

The exploitation of high-voltage GaN power switches enables the development of power converters with superior characteristics with respect to components developed with heritage silicon-based technologies. One of the key advantages of GaN switches is their very fast commutation capability due to reduced parasitic capacitance and inductance with respect to silicon devices. The capability of an accurate evaluation of the switch commutations in the design phase is of crucial importance to maximize performance and avoid reliability or electromagnetic compatibility issues in the final converter. In this paper, an accurate evaluation of high-voltage GaN HEMT commutations is performed, exploiting detailed non-linear dynamic models of transistors and electromagnetic simulations of a PCB. A deep insight into the commutation waveforms in the intrinsic device (i.e., conductive drain current and intrinsic node voltages) is proposed to evaluate and explain the mechanisms of almost lossless turn-off and turn-on commutations in a 7 kW DAB converter. The influence on the performance of the PCB parasitics and the driver characteristics are accurately reproduced by simulations, suggesting important guidelines for the optimal design of power converters fully exploiting GaN HEMT’s potential. This detailed simulation/analysis approach for transistor commutation is typically adopted in Radio Frequency amplifier design but also becomes very valuable in power converter design when the very fast commutations of a GaN HEMT at a high switching frequency cannot be fully described and taken under control with conventional approaches used in power electronics design. The simulation results are confirmed by experimental data.

LED technology paved way to rapid advancements in the automotive lighting with increased demands for safety and luxury. This paper presents design and development of a LED driver for DRL application using a modified Buck-Boost converter with GaN HEMT switching at 500kHz. High performance is achieved by using the GaN based HEMTs as switching device, with the primary advantage of switching at higher frequency with low losses. The converter topology is analyzed for the Bright/Dim operation requirements of the DRL application. GaN LED driver with a power rating of 9W was developed. Measures were taken to meet the critical parasitic restraints of high frequency power switching. The high performance of the module is test evaluated and it is having higher power density compared to the presently available DRL drivers. The technology has evolved as import substitute in this area of application. The proto model is further encapsulated to be demonstrated in the rugged environment of the in-vehicle operations.

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Converters based on dual active bridge (DAB) topology are becoming more popular with its high-power density and possibility of bi-directional power flow. Popular applications include renewable energy storage and conversion and electric vehicle charging, but it could also be used for electric transport of lower power rating, like electric scooters and bicycles. The advances in wide band-gap (WBG) semiconductor technology, such as gallium nitride (GaN) high-electron mobility transistors (HEMTs), have prompted the use of these transistors which have lower conduction losses and work with higher switching frequencies. Calculations for Silicon MOSFET switching losses are well established, but as GaN HEMT have smaller parasitic capacitances, the latest transistor switching transients do not fully match with the existing model’s Miller effect. Switching loss calculation has been proposed that takes into consideration this difference. In this paper the regular MOSFET switching loss calculation is compared with the updated GaN HEMT switching loss results. A 300W GaN based DAB prototype was built to compare both of the calculation results with experimental measurements.

The growing demand for efficient and compact electric vehicle (EV) chargers has led to the adoption of gallium nitride high electron mobility transistor (GaN-HEMT) as a switching device used in converters. By leveraging the high switching frequency and superior characteristics of GaN devices, the proposed RGDC minimises gate power loss while ensuring high efficiency and thermal stability. The integration of a feedback-based closed-loop mechanism results in dynamic regulation of the switching signal, which is crucial for voltage stability and ripple suppression in EV charging environments. Simulations in LTspice validate the design, revealing substantial performance enhancements such as a reduction in output voltage overshoot from 39.06 V to 23.86 V, an improvement in average inductor current from 1.219 A to 1.749 A, and a significant decrease in gate current from 1.6 A to 80 mA. The converter achieves a peak efficiency of 94 % in closed-loop operation, compared to 75 % in open-loop operation, with corresponding reductions in power loss across various load conditions. These outcomes demonstrate the proposed closedloop operation of RGDC's potential to support compact, energyefficient, and thermally robust EV charger architectures.

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Power loss calculation and junction temperature analysis are of great significance to the thermal design in power electronics. In this paper, an electrothermal simulation analysis on GaN HEMT is performed based on the power loss calculation under actual working conditions including conduction loss and switching loss. By coupling the power loss and heat conduction process, the temperature distribution of the GaN HEMT, as well as the junction temperature, can be obtained by both the FEM thermal simulations and RC thermal model. The results show that the switching loss accounts for about 20% of the total power loss, far less than the conduction loss of 80% under the given working conditions. The RC thermal model based on the thermal resistances obtained by FEM simulations can predict the results of FEM simulations well for cases with different heat source distributions, while the model with original thermal resistances from thermal conductivity and size of layers cannot provide accurate predictions. The maximum junction temperature occurs in the case of concentrated distributed heat sources. This research is promising to provide valuable references for thermal management in GaN electronics.

Cryogenic power electronics is regarded as the next step to improve the converter efficiency and power density. It is advantageous in many different applications, including aerospace, renewable energy, transportation and so on. Among all different semiconductors, gallium nitride (GaN) was found more advantageous with significant loss reduction at cryogenic temperature. In this paper, overcurrent test is performed and analyzed for a high-efficient commercial GaN high electron mobility transistor (HEMT). The experimental results demonstrate a significant improvement of the device overcurrent capability at cryogenic temperature (from 160 A at room temperature to 250 A at cryogenic temperature). The operating mechanisms behind the overcurrent test are investigated and discussed. Finally, a 5 kW GaN HEMT based cryogenic Buck converter is built and tested. Maximum efficiency of 98.5% is achieved at 1.5 kW output power and around 1% efficiency improvement can be achieved when compared to room temperature operation. Another GaN HEMT based four-switch Buck-boost converter is evaluated at cryogenic temperature, maximum efficiency improvement of 1.5% is observed when compared to room temperature.

This paper explores a resonant gate driver circuit (RGDC) with closed-loop control for Gallium Nitride (GaN) high-electron-mobility transistors (HEMTs) in buck power conversion systems. Modern industries increasingly rely on high-frequency electronic devices, particularly Wide Bandgap (WBG) semiconductors like Silicon Carbide (SiC) and Gallium Nitride (GaN), for their superior characteristics over conventional silicon. The RGDC design aims to minimize gate power loss during high-frequency operation, enhancing overall performance. Simulations validate the effectiveness of the approach, showcasing improved voltage stability, reduced overshoot, and enhanced regulation compared to open-loop control. The closed-loop scheme dynamically adjusts and maintains desired output levels, leading to enhanced performance, stability, and reliability in GaN HEMT-based converters.

With wider electrification in various sectors, there is a great demand for high-power, high-efficiency and high-power-density converters. Compared with conventional Si devices, the ultra-fast-switching speed of gallium nitride (GaN) high-electron-mobility-transistors (HEMTs) can enable power electronics converters to achieve very high switching frequencies, which can help to reduce the current ripple and hence significantly reduce the filtering components such as filter inductors and capacitors. The high-frequency GaN HEMT converter can also be used for very high-speed, high-fundamental-frequency motor drives and other applications. This article has evaluated the performance of GaN HEMTs through double pulse test (DPT) as well as continuous test in a DC/AC three-phase converter, which provides benchmarking results demonstrating the capabilities of GaN devices. A detailed power loss and efficiency model considering the parasitic capacitive effect has been developed for GaN converters and an experimental prototype has also been built to evaluate the converter performance. Through experimental evaluation, 3 kW output power, 300 kHz switching frequency and 97.06% efficiency have been achieved. Further, 1.5 kW output power, 600 kHz switching frequency with an efficiency of 94.42% have also been achieved.

Cryogenic power electronics is both advantageous and indispensable in many applications, like deep space probe, military electric vehicle, magnetic resonance imaging etc. Among different semiconductors, the gallium nitride (GaN) high electron mobility transistor (HEMT) is the most promising candidate for cryogenic applications with significant conduction loss and switching loss reductions. Moreover, there is no carrier freeze out effect for the GaN HEMTs, which is applicable in extreme low temperature operating conditions. In this work, the efficiency of GaN HEMTs based power converters with different power levels (from several Watts to several kiloWatts) are evaluated at cryogenic temperature. Three different commercial GaN HEMTs are used in these power converters, including the Texas Instruments LMG5200 80 V GaN half-bridge power stage with integrated gate driver, the GaN Systems 650 V bottomcooled GaN HEMT GS66516B, and the 650 V top-cooled GaN HEMT GS66516T from GaN Systems. Moreover, two different cryogenic power converter evaluation methods (cryogenic chamber and liquid nitrogen channeled through cold plate) are investigated. Three of these power converters are evaluated by using a cryogenic chamber and such that the converter operating environment temperature can be regulated. One of the power converters is evaluated by using liquid nitrogen (LN2) channeled through a cold plate, where the gate driver can be designed to operate at non-cryogenic temperatures to ensure the safe operation of the system. Due to the degraded performance of conventional magnetic components, air core magnetics are used in these power converters to improve the converter efficiency. Efficiency improvements at cryogenic temperature are observed for all the GaN HEMTs and air core magnetics based power converters, which are promising for cryogenic power electronics applications.

A novel physics-based temperature-dependent analytical model for non-linear capacitances of the lateral AlGaN/GaN HEMT with a field-plate structure is presented in this paper. Compared to the State-Of-The Art, the proposed model is fully analytical and does not contain any fitting parameters. For Qgd charge that determines the duration of Miller’s plateau in Vgs and dominantly affects power losses in high-frequency hard-switching converters, the model shows decrease of only 0.6%, when temperature is increased from 25 to 150°C. The Cgs capacitance is found to be only fringing in nature, giving temperature-independent Qgs charge. The model for Ciss (Vds), Coss (Vds) and Crss (Vds) is experimentally verified at 25°C. In order to estimate the effect of elevated temperature on the efficiency of high-switching frequency converter, the proposed temperature-dependent capacitance model Id (Vgs, Vds) model from the literature are implemented into the power loss model of a high-frequency buck converter. At room temperature and 20MHz of switching frequency, the proposed capacitance model is verified by good agreement between measured and simulated efficiency curves. Using the same switching frequency and elevated temperature of 150°C, simulated efficiency shows lower values compared to the room temperature. Increase in total power losses is associated with 29% higher on-resistance at 150°C. It was concluded that high-temperature operating conditions will reduce converter’s efficiency even at high switching frequency, due to higher impact of increased on-resistance compared to reduced gate charge.

With the rapid development of new energy technology, telecommunication technology, and big data centre, the power density and conversion efficiency of the power supply have put forward higher requirements. Gallium nitride (GaN) devices are characterised by high switching speed, low on-resistance, and no reverse recovery loss; LLC converters have become one of the most popular isolated high-efficiency DC-DC converter topologies with their unique soft-switching characteristics, and so they have been widely used in various scenarios. In this paper, a $350 \sim 400 \mathrm{~V}$ to 48 V LLC prototype is built based on a half-bridge LLC topology using GaN HEMTs as primary power tubes, combined with planar transformer technology and synchronous rectification in order to minimise the switching losses of the LLC resonant converter at high MHz frequencies. The converter achieves a peak efficiency of 95.58% and a full load efficiency of 93.74%, which is experimentally verified to be the correct design solution.

The reliability of power converters is intricately tied to the variations in the junction temperature of semiconductor devices. Therefore, possessing accurate models of these components is of paramount importance. This research introduces an electrothermal model focusing on Gallium Nitride (GaN) based dc–dc converters. The experimental evaluation leverages a GaN-based two-level buck converter (TLBC), where current control is achieved via pulsewidth modulation (PWM), while a comprehensive thermal model is developed in the range of 10–$\text{500} \,\text{kHz}$ at fixed switching frequencies. The test-bed involves direct temperature measurement utilizing infrared thermal sensors. The proposed model undergoes validation through comparison with experimental data in steady-state and dynamic conditions. Finally, the contribution of this work is to generate an accurate electrothermal model of a TLBC based on GaN-high-electron-mobility transistor technology transistors to enable active thermal control implementation in steady-state and dynamic mode. The aim of the study is to address the management of component temperature rise given the need for full integration requirements as a major challenge in new-generation of dc–dc power converters.

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In modern automotive electronics, there are uprising demands on enhanced power density and reliability for power delivery systems. To achieve high power density, single-stage gallium–nitride (GaN)-based power converters at high switching frequencies (<inline-formula> <tex-math notation="LaTeX">$f_{\mathrm {SW}}$ </tex-math></inline-formula>) are highly desirable but face formidable reliability challenges in the aspects of electromagnetic interference (EMI) suppression and consequential output voltage <inline-formula> <tex-math notation="LaTeX">$V_{O}$ </tex-math></inline-formula> regulation. To address these challenges, this article presents a GaN-based switching power converter that employs an anti-aliasing multi-rate spread-spectrum modulation (MR-SSM) technique for EMI suppression and an in-cycle adaptive zero-voltage switching (ZVS) technique to minimize switching power losses. Compared with classic fixed-rate SSM (FR-SSM), the proposed MR-SSM technique spreads EMI spectra in a wider frequency range without aliasing spikes and, thus, reduces peak EMI more effectively. To improve efficiency, an elastic dead-time (<inline-formula> <tex-math notation="LaTeX">$t_{\mathrm {dead}}$ </tex-math></inline-formula>) control facilitates in-cycle ZVS despite of a continuously changing <inline-formula> <tex-math notation="LaTeX">$f_{\mathrm {SW}}$ </tex-math></inline-formula>. An IC prototype based on this design was fabricated on a 180-nm HV BCD process, with an active die area of 0.87 mm². The converter can handle a variable automotive-use battery voltage from 5 to 24 V and delivers up to 1.2-W power to a regulated output <inline-formula> <tex-math notation="LaTeX">$V_{O}$ </tex-math></inline-formula> at 1 V, with a peak efficiency of 90.2%. It accomplishes a 29% further peak EMI reduction compared with the FR-SSM counterpart.

When applying switching power converter in automotive electronics, electromagnetic interference (EMI) is a critical issue to be addressed for reliable and safe driving. This is especially important for high-frequency gallium-nitride (GaN) power system. Traditionally, passive filter and active control circuits are widely employed to suppress EMI and thus fulfill the EMI standards through in-house testing. However, the pre-defined testing conditions can be quite different from the applications, inducing safety risks. To solve this dilemma, risk-based EMI standards have been established to link the EMI assessment to real applications [1]. Meeting this trend, an adaptive spread-spectrum modulation (SSM) scheme was reported [2]. But it highly relies on an ideal model between EMI and power conditions. On the other hand, an active filter was constructed [3] to dynamically cancel EMI. However, its effectiveness is impacted by the limited bandwidth (BW). To overcome the above issues, this work proposes a wide-bandwidth closed-loop EMI regulation for GaN power converters.

In order to model GaN device dynamic RDSon value due to trapped charge, a measurement circuit to accurately measure device dynamic RDSon value under different OFF-state time and ON-state time is at first proposed. Based on measurement results, an analytical model with different cells is proposed to represent dynamic RDSon evolution. It is then represented as a behavioural voltage source to compensate device ON-state VDS voltage, which can be implemented easily into device manufacturer model in Spice-type electrical circuit simulator. The model is then validated by comparing with the measurement on device dynamic RDSon value of different switching frequencies, where the model agrees with experimental results on both transient and stabilized dynamic RDSon value.

Switch-mode power converters commonly operate at switching frequencies from kilohertz to a few megahertz, traditionally relying on silicon-based transistors and control circuitry. However, parasitic limitations in silicon devices constrain further frequency scaling. This article presents a fully gallium nitride (GaN)-based dc–dc converter designed for high-frequency operation. The proposed architecture employs a GaN-based ring oscillator for on-chip pulsewidth modulation generation and includes all converter modules operating within the 8–43 MHz range. Experimental results validate the proposed design, demonstrating its feasibility and performance in high-frequency power conversion. The findings support the development of integrated GaN-based power conversion systems for advanced system-on-chip applications.

The comparator is a vital block in any integrated DC-DC power converter for both control and protection functions. Monolithic GaN HEMT power converters offer superior power switching performance with lower on-resistances and capacitances, however they suffer from poor analog performance due to their lack of complementary devices and poor device mismatch as well as a limited range of devices. This paper presents the design of a depletion-mode input pair based regenerative comparator monolithically integrated on a GaN-on-Si process. This paper aims to investigate and demonstrate the input-referred offset performance of such a comparator. The structure delivers a transistor level simulated 1-σ input-referred offset of 3.6 mV without the use of any offset cancellation techniques. It achieves rising and falling propagation delays of 29 ns and 22 ns, respectively with a 100 mV overdrive and 1 pF load capacitance. The comparator occupies an area of approximately 0.055 mm2 and has a quiescent current consumption of 63 μA.

Temperature is a critical parameter for the GaN HEMT as it sharply impacts the electrical characteristics of the device more than for SiC or Si MOSFETs. Either when designing a power converter or testing a device for reliability and robustness characterizations, it is essential to estimate the junction temperature of the device. For this aim, manufacturers provide compact models to simulate the device in SPICE-based simulators. These models provide the junction temperature, which is considered uniform along the channel. We demonstrate through two-dimensional numerical simulations that this approach is not suitable when the device undergoes high electrothermal stress, such as during short circuit (SC), when the temperature distribution along the channel is strongly not uniform. Based on numerical simulations and experimental measurements on a 650 V/4 A GaN HEMT, we derived a thermal network suitable for SPICE simulations to correctly compute the junction temperature and the SC current, even if not providing information about the possible failure of the device due to the formation of a local hot spot. For this reason, we used a second thermal network to estimate the maximum temperature reached inside the device, whose results are in good agreement with the experimental observed failures.

Gallium Nitride power devices, with an energy bandgap roughly three times larger than that of silicon, provide lower specific conduction resistance and faster switching speeds. These characteristics enable the design of more efficient and compact power converters. However, challenges such as high voltage overshoot during rapid switching transients continue to limit the full potential of GaN technology. This study presents an innovative alternative to the conventional wire-bonded GaN power module through the development of a flip-chip design employing solder ball bonding. A detailed finite element analysis (FEA) model is constructed to evaluate the junction temperature and parasitic inductance of power modules. Furthermore, the bonding strength is examined to ensure the mechanical integrity of the design. The proposed flip-chip design is experimentally validated by static characterization and double pulse test. The design reduces parasitics and enables compact, efficient GaN power electronics for high-frequency use.

In this work, a GaN/Si hybrid power switch is proposed to overcome the disadvantages of dynamic ON-resistance degradation and limited avalanche capability for pure-GaN switches. The proposed hybrid switch exhibits suppressed dynamic ON-resistance, increased power conversion efficiency and enhanced avalanche robustness when compared to the pure-GaN switch with exactly the same ratings. By employing an active gate control pattern between GaN and Si devices within the hybrid switch, the dynamic ON-resistance is significantly reduced by more than 20%. Consequently, it increases the efficiency by 2% in a 48-to-24 V DC-DC buck converter at the switching frequency of 500 kHz and an output power of 240 W. The single-event avalanche energy withstanding capability shows a two-order-of-magnitude improvement and no failure is observed after a 1000-cycle repetitive UIS (Unclamped Inductive Switching) test.

Superconductivity is a technology with the potential to enable new and exciting fields, from transportation to energy production. Cryogenic power supplies are useful components for applications involving superconductivity. This article focuses on the design of a cryogenic gallium nitride (GaN) enhancement mode high-electron-mobility transistor (E-HEMT) synchronous buck converter, which achieves an efficiency of 99.2% at 3 kW, and uses a nanocrystalline filter inductor within the cryogenic environment. An air-core inductor-based method is used to separate the switch and inductor losses of the converter, and film boiling in liquid nitrogen is used to set the safe operating range of the converter. The selection of magnetic materials and litz wire at cryogenic temperatures are evaluated, where a nanocrystalline inductor is designed, which shows reduced losses in liquid nitrogen compared to at room temperature. It is shown that by cryogenically cooling the GaN switches their losses are halved compared to when operating at room temperature under the same conditions.

This paper addresses the analysis, design and implementation of a 2 MHz, 12 V, 600 mA, GaN-based Active-Clamped Isolated SEPIC Converter (ACISC) supporting full ZVS throughout the 9V-18V automotive range and intended to provide isolation and power interface between the 12V battery and the low-power subnet. Designed for resonant DCM operation and leveraging the high switching frequency enabled by GaN devices, the selected topology leads to a strong reduction in total magnetic size and footprint while maintaining a high efficiency profile. This paper aims at showing the theoretical model specifically developed for full ZVS resonant DCM operation of the ACISC converter together with the design and implementation of the transformer. The proposed model has been verified through simulations as well as experimental measurements taken on a 7.2 W GaN-based prototype employing a planar transformer.

This paper reports an automotive-use 5–24V VIN to 1V Vo GaN-based power converter that achieves 20dBμV electromagnetic interference (EMI) reduction with anti-aliasing multi-rate (MR) spread-spectrum modulation (SSM) and in-cycle zero-voltage switching (ZVS). Compared to classic fixed-rate (FR) SSM, the proposed MR-SSM technique accomplishes 29% further EMI reduction, with the use of an active shaping controller. To improve the efficiency, an elastic tdead control facilitates in-cycle ZVS switching despite of random fSW variation caused by any SSM. The design was implemented on a 180nm BCD process, with an active die area of 0.87mm2. It achieves a peak efficiency of 90.2% over a load range of 0.01 to 1.2W.

A low-parasitic-inductance gallium nitride (GaN) high-electron-mobility transistor (HEMT) half-bridge integrated power module is proposed in this paper. Organic substrate packaging technology is adopted, and the power loop inductance is reduced to 457.07 pH by optimizing the layout and packaging structure to meet the demand for low parasitic inductance in high-frequency power conversion systems. Combined with Ansys Q3D electromagnetic simulation and double-pulse testing, the turn-on and turn-off inductances of the driving loop are 1.56 nH and 1.33 nH. Under the 80V/16A operating condition, the voltage overshoot of the module is only 3.39V. Comparative experiments have shown that compared with commercial modules, the designed low-inductance module exhibits significant advantages in efficiency, stability, and dynamic response. Through multiphysics field collaborative optimization, this study solves the problems of voltage oscillation and loss caused by parasitic inductance in high-frequency applications of the module. It provides important theoretical guidance and practical references for low-inductance packaging design, board-level structure optimization, and high-frequency module integrated packaging of GaN HEMT half-bridge modules.

Because the limitation of the voltage rating of gallium nitride enhancement mode high electron mobility transistor (GaN E-HEMT), the conventional resonant converter with GaN E-HEMT is not suitable for high input voltage applications. The cascoded dual-half-bridge resonant converter is more suitable for high input voltage applications because the voltage stress on power devices is reduced. Also, the efficiency is enhanced because zero voltage switching is achieved in reducing switching loss. Since the magnetizing components are integrated, higher power density can be reached. The operating principles and the steady-state characteristics of the cascoded dual-half-bridge resonant converter are analyzed. Finally, an experimental prototype is implemented with input voltage range of 740 V to 800 V, output voltage of 15 V, rated power of 105 W, and switching frequency of 500 kHz. The experimental results reveal that when input voltage is 800 V, the highest efficiency is 92.9% at 50% load, and the full load efficiency is 90.5%.

High voltage (HV) batteries, from 400 V up to 800 V, are a recent breakthrough in the automotive field. These batteries along with the required power converter are able to provide higher efficient systems with enhanced power density, at the same time faster charging speeds can be achieved. Depending on the automobile manufacturer and the electric vehicle type, multiple DC buses of HV and LV are employed simultaneously, which demands several conversion stages. For this purpose, isolated multiport DC/DC converters are a promising solution to adapt these different HV and LV levels while allowing a reduced number of conversion stages and high efficiency. This is only achievable because a multiwinding transformer (MWT) is used to couple the multiple cells and hence compose the overall multiport DC/DC converter. Therefore, in this paper, a GaN-based multiport resonant converter with a wide input voltage range is investigated to interconnect multiple HV and LV DC buses. To reduce the voltage and current effort of the GaN devices, the approach employs an input-series and output-parallel interconnection (ISOP). Further, as a novel approach, only one resonant tank on the input side is used to reduce parameter deviations among the multiple ports. Finally, the investigated topology is validated in simulation as well as by means of a hardware demonstrator with a peak efficiency of 94.23 %.

In this work, the emission, in terms of magnetic and electric fields, on a surface very close to a GaN-based DC-DC converter board is analyzed. The use of GaN devices allows the adoption of higher switching frequencies, with the consequence of observing electromagnetic fields emitted in frequency ranges different from the usual ones related to conventional silicon-based converters. This analysis is based on the near-field scan, using specific hardware for the acquisition in proximity to the PCB. The acquisition was performed for both $E$ and $B$ fields, considering the vector components parallel and orthogonal to the PCB surface. The obtained spatial distribution of the electromagnetic fields enables useful considerations for the optimization of the PCB, which is intended not only in terms of paths of the tracks, but also in terms of the position of the active and passive circuit elements, based on their distinctive electromagnetic emission profile.

No abstract available

This paper presents the analysis, simulation and experimental studies of a GaN device-based full bridge isolated DC-DC converter switching at 500 kHz. For such high frequency converter boards involving small SMD packages, electromagnetic and thermal issues become much significant. These have been addressed in this work. The GaN half-bridge (HB) circuit modules have been developed as units for easier testing and maintenance in the lab. FEM based electromagnetic simulations have been performed for the GaN HB board to validate the reliability of performance at such high frequencies. From FEM-based electromagnetic studies, the board parasitics have been estimated. These results also serve as inputs to the thermal simulation package. The device-level thermal simulation is also performed using FEM. The thermal equivalent circuit diagrams are presented to calculate the temperature rise values analytically. Comparative studies on thermal aspect are presented for both hard switching (HS) and free-wheeling (FW)GaN devices and two GaN half-bridge cards. Experimental results have been recorded at 1.8 kW @500 kHz with 400 V DC Bus. It is found out that the simulation results are in good agreement with the experimental results.

This paper presents a high efficiency high power-density LLC DC-DC converter for Electric Vehicles (EVs) on-board low voltage DC-DC converter (LDC) application. In the proposed LDC, primary switches achieve ZVS turn-on and secondary synchronous rectifier switches achieve ZVS turn-on and ZCS turn-off. To reduce current stress and improve efficiency, three phase interleaved LLC DC-DC converters are paralleled to provide more than 200A load current. Switch-Controlled Capacitor (SCC) technology is used to achieve the load current sharing of the three phase LLC DC-DC converter. In addition, GaN HEMTs are used in the transformer primary to improve the switching frequency and power-density. To verify the analysis, a 3.8kW(14V/270A) LLC DC-DC converter prototype is designed. The experimental results show that full load efficiency is 95.8% at 270A load current and 3kW/L power-density is achieved.

In recent years, the trend in power electronics has been toward high-efficiency and high-power-density converters. Additionally, this trend has allowed electric vehicles to accommodate larger batteries, which necessitate bi-directional capabilities not only for driving but also for vehicle to grid (V2G), etc. This article proposes a comparative analysis of GaN-based bi-directional topologies, namely the dual active bridge (DAB) converter and the CLLC converter. To ensure a fair analysis of the proposed topologies, prototypes with the same target of efficiency above 97.5% and a power density of 5.5 kW/L have been constructed. This research can support the adoption of 10.9 kW bi-directional topologies in GaN-based on-board chargers (OBCs) for EVs.

This paper presents a 4 kW GaN-based galvanically isolated bidirectional DC/DC converter suitable for on-board auxiliary power supply systems, interconnecting the HV battery with the LV power system. To enable the trend towards higher levels of electrification, a second LV level of 48 V is introduced to supply the high-power consumers, relieving the 12 V grid on the one hand and/or avoiding using additional costly isolated converters connected to the HV batteries on the other. The built converter prototypes aim to demonstrate higher efficiency, compactness and lower filter requirements of the proposed circuit.

This paper proposes the designing procedure for Inductor-Inductor-Capacitor (LLC) Resonant DC-DC Converter using GaN HeMT MOSFET for on-board battery charger used in Electric Vehicle application. Based on LLC Converter's features and characteristics, design specification is studied. By using Fundamental Harmonics Approximation model, Zero Voltage Switching (ZVS) on the primary side has been reported by operating in different operating regions. The control scheme for the proposed converter is discussed to regulated output voltage. Finally, the model is proposed and tested using MATLAB simulation to transform 400 V input voltage to an output voltage range of 64.8-86.4 V at 3.3 KW, taking all parameters into account step by step.

A 6.6kW 500kHz bidirectional isolated DC/DC converter based on GaN and SiC wide band gap (WBG) semiconductor devices is developed for 800V electric vehicle (EV) on-board charging, which is simpler and more reliable than the method of 800V output using multilevel topology. Firstly, the working characteristics of resonant DAB topology using phase-shift control are analyzed. Compared with the delay-time control strategy, it has the factures of narrow switching frequency range and small turn-off current, which is very suitable for high frequency applications of SiC devices. Secondly, a magnetic integrated high-frequency transformer was designed, and Maxwell software was adopted for simulation, comparison, and optimization. Compared with the traditional 90kHz transformer design, the volume was reduced by about 50%. Thirdly, based on the specifications of EV on-board charger, the loss breakdown calculation of the worst-case working condition of charging and discharging mode is carried out to verify the rationality of the design. Finally, based on water-cooled heat dissipation, a 500kHz 6.6kW 800V bidirectional DC/DC experimental platform was built. The full power output voltage range is form 550V to 900V, and the peak efficiency more than 98% at normal temperature, which verified the feasibility of the high-frequency hybrid application design of GaN and SiC devices.

This paper focused on design and simulation of 3.3 kW, 400V DC output, Gallium nitride high electron mobility transistors (GaN-HEMT) based Dual Active Bridge (DAB) DC-DC Converter for EV On-board Chargers (OBC). An optimized design of converter with high power density and high efficiency is proposed. GaN-HEMT and Planar Transformer are selected to achieve high power density due to its compact size and high switching frequency. Proposed GaN based converter design, overall component selection, modes of operation and control strategies are discussed in details. The simulation of proposed converter is carried out in Plexim software. The performance analysis of GaN based DAB and SiC based DAB are presented in Plexim software. The overall device losses of both converters are compared and presented.

This paper presents a bidirectional CLLC converter solution for the dc-dc stage in plug-in electric vehicle (PEV) on-board battery chargers. The proposed architecture allows the converter to operate at resonance for the bidirectional constant-power (CP) load range with a variable bus voltage, while frequency modulation is employed for the constant-current (CC) load range in the grid-to-vehicle (G2V) mode with a fixed bus voltage, resulting in a limited bus voltage range. This enables the use of 650-V Gallium nitride (GaN) devices for the primary and secondary sides’ switches. The design flow is presented and a 1-kW high-frequency prototype is implemented. GaN reverse conduction characteristics are investigated and employed for the high-frequency current rectification. The prototype operates with soft switching across the operational range, achieving an efficiency of up to 95.7%, with the resonant inductances integrated in the transformer.

The dual active bridge (DAB) is a widely used isolated DC-DC converter topology, particularly in automotive on-board charger (OBC) applications due to its high power density, inherent bidirectional power flow and reliability. Besides, the implementation of multilevel switching cells helps reduce the voltage stress in all devices, allowing the converter to be used in high voltage battery systems (600 V and higher). Due to circuit non-idealities, a steady-state DC offset current occurs at the transformer which leads to increased power losses, loss of zero-voltage switching and possibly magnetic core saturation. This paper discusses the physical implementation of an active cancellation method of the steady-state DC offset current, applied to a GaN-based three-level dual active half bridge (DAHB). The proposed method uses a duty cycle modulation in the primary half-bridge to compensate the non-ideal behavior of the devices. Experimental validation is done on a 1.5 kW three-level dual active half bridge converter based on 650 V GaN transistors.

Owing to the large di/dt and dv/dt introduced by Gallium Nitride (GaN) switching devices, optimization of parasitic elements in a converter becomes very critical. This paper evaluates the impact of the parasitics of an high-frequency isolation transformer and printed circuit board (PCB) on the performance of a GaN based Dual Active Bridge isolated DC-DC converter. An iterative optimization tool is built to optimize the isolation transformer in terms of its weight and efficiency. Initial testing of the prototype revealed that parasitic elements of the PCB have adverse affects on the converter and it did not work beyond 35 VDC. Hence, based on practical results, PCB parasitic elements were optimized. With optimized layout design, converter did operate as it was intended to. However, due to excessive ringing in the switching voltages, converter efficiency was below the target efficiency (η > 90%). To eliminate this high-frequency ringing, inter-winding capacitance of the transformer was reduced by changing the winding configuration. This successfully reduced the ringing and aided the converter to reach its target efficiency.

No abstract available

This paper presents a GaN-based high power density and isolated DC-DC converter with dual active bridge topology for DC/DC stage of a bidirectional 400V EV on board charger (OBC). Gallium Nitride (GaN) technology in top side cooled package is employed to achieve higher switching frequency with more compact passive components solutions. The paper introduces the design parameters for the DAB circuit with wide range output, variable frequency controller as well as two high frequency planar transformer designs to achieve 125 kW/L power density. System level loss breakdown and circuit protection scheme and implementation are also provided. The 7.2kW DAB prototype has been implemented and tested in constant voltage (CV) mode, proving exceptional power density of 37 kW/L with 98.8% peak efficiency.

No abstract available

In this paper, a GaN based modified non-isolated integrated on-board charger (IOBC) using a low value zero sequence inductance of traction motor and an inverter for class A and B segment electric vehicles (EV’s) with dual power conversion stages is proposed. In the modified configuration, the traction motor and the inverter will be used as components in the back-end DC to DC buck converter instead of in the front-end AC to DC boost converter as available in the conventional IOBC configuration. The modified IOBC configuration satisfies the permissible THD distortion limit of the Japanese utility companies and also keep the output peak-to-peak battery current ripple within the specified limits. Furthermore, electrical safety issues such as touch currents due to the presence of ground leakage currents caused by the low common-mode impedance of the non-isolated IOBC are solved by adding a split boost inductor and a floating EMI filter in the proposed modified IOBC configuration. The feasibility of the modified IOBC configuration and the solutions for the safety issues are verified from suitable simulation and experimental results.

No abstract available

Significant technological advancements have been made towards high-density high-frequency power conversion using Gallium Nitride (GaN) devices. As such, it is possible to shrink the size of passive components such as magnetics and capacitors resulting in compact designs. Nonetheless, high switching frequency leads to stronger conducted emissions occurring at higher end of the frequency spectrum necessitating use of additional passive filtering to meet emissions standards. Ultimately, this defeats the purpose of pushing towards high switching frequency. This paper presents a unique integrated Electromagnetic Interference (EMI) filter solution for typical isolated high-voltage DC-DC resonant converters. Three design methods on magnetics design, layout and software/control techniques are proposed. These concepts are implemented on planar Printed Circuit Board (PCB) based 6.6 kW CLLLC resonant converter. The proposed methods do not require any external DC filters and can minimize EMI filter volume requirement in a typical OBC or Power Supply Unit (PSU) application. Furthermore, these solutions can be extended to LLC, CLLC, Series Resonant Converter (SRC) type topologies, both single and three-phase as well.

No abstract available

Electric vehicle (EV) on-board chargers (OBCs) should have high efficiency and high power density. Since the transformers in isolated OBCs generally lower both of these metrics, this paper proposes a novel non-isolated OBC with very high efficiency and a low component count. Active filtering is proposed to allow the use of smaller dc-link film capacitors to further improve power density. This paper discusses the design process for the dc-link capacitors and the operation of the active filtering control. Simulation results show that for level 2 charging, the proposed converter has a peak efficiency of 98.8% and efficiency of 98.6% at full 3.3 kW load. Furthermore, the simulation results confirm acceptable THD and power factor performance of the proposed topology.

The aim to reduce the weight and volume of equipment is driving the evolution of embedded power electronic architectures. This trend has given rise to the adoption of a 48V on-board network. Advanced topologies such as switched capacitor DC-DC converters, combined with the integration of Wide Bandgap (WBG) semiconductors, represent a promising direction for the development of 48V systems. This paper presents a comparison methodology, based on a power density optimization of 48V-to-12V, 1KW output power converter. This method employs volume optimization as a critical metric for comparison. 4-Level Flying Capacitors Multilevel (FCML) and 3:1 Hybrid Dickson topologies are compared to a conventional 2-Level Buck converter across three semiconductor technologies: Lateral and Vertical Silicon MOSFET, and High Electron Mobility Transistor (HEMT) Gallium Nitride (GaN). Considering models of power semiconductor losses, volume of passive components and heat sinks, this approach facilitates a balanced comparison to identify the most compact topology/technology combination. First results give as an optimal solution a 3:1 Hybrid Dickson topology using HEMT GaN technology, which achieves superior efficiency and a higher power density.

No abstract available

On-board electric vehicle (EV) chargers provide ac to dc conversion capability to charge a high-voltage battery pack. As they are carried within a vehicle at all times, high efficiency and high power density are desirable traits for such a converter, in order to reduce the size, weight, and power loss of the system. Bidirectional capability is also desirable for an on-board charger to support vehicle-to-grid ancillary applications. This paper presents the implementation of a bidirectional single-phase ac-dc converter, converting between universal ac (120-240 VAC) and 400 VDC. Discussions of system architecture, control, mechanical design and assembly, and thermal management of an interleaved 6-level flying capacitor multilevel (FCML) power factor correction (PFC) stage with a twice-line-frequency series-stacked buffer (SSB) stage are included. Experimental results demonstrating dc-ac inverter operations at the kilowatt scale are provided. A peak efficiency exceeding 99% is observed, and a maximum power of 6.1 kW is tested.

In this article, a new HV-LV converter for electric vehicle applications is proposed. The topology combines a dual active bridge-series resonant converter (DAB-SRC) with an interleaved buck/ boost converter. An additional phase-shift control on the LV side is introduced, allowing the active switches to operate near-DCX, resulting in a significant reduction in switching loss. Furthermore, the circulating current is reduced by half compared to conventional [S. Inoue et al. 2017] when operating with a wide voltage range, leading to a reduction in conduction loss. As a result, the switching frequency is doubled compared to existing topology, improving power density by 20.7%. The effectiveness of the proposed topology is verified through experiments on a 6.1 kW prototype, with an LV-side voltage of 48 V/4 kW and 9–16 V/2.1 kW, an HV-side voltage of 400–840 V, and a switching frequency of 200 kHz. A peak efficiency of 96.44% and a power density of 7.5 kW/L were achieved.

This work discusses the usage of two new power semiconductor technologies. One is Galium nitride (GaN) switches which belong to the wide-band gap devices. The second one is chip-embedding of silicon (Si) devices inside the PCB. This will be done by explaining the two new technologies and then providing a system design for a HV/LV DC-DC converter utilizing both these two technologies which could be used in automotive applications for the converter charging the auxiliary 12 V battery.

This paper presents a comprehensive study on fault-tolerant and redundant HV/LV DC-DC LLC converter designs for Autonomous Drives (AD) L4/L5 EVs, medical applications, and aircraft. The main goal is to ensure high reliability and safety through a fail-operational mechanism. These designs address safety requirements for consistent LV power supply in essential EV functions like power steering, braking, acceleration, airbag activation, and controller power supply. The fail-operational LLC topologies support a 1.8kW, 400V system with an input voltage range of 290V to 490V, providing reliable 12V LV supply. Extensive PLECS analysis demonstrates significant advancements in safety and reliability, promising improved performance for AD L4/L5 EVs.

This paper proposes multiport DC-DC converter for on-board charger (OBC) EV applications with simultaneous charging of high voltage (HV) battery and low voltage (LV) battery. The evolution of this converter involves replacing the switch found in a conventional step-up converter with a pair of series-connected switches. This arrangement allows for an additional switch node that generates a LV output. the proposed converter has benefits of high voltage gain for HV side, continuous input current, a reduced switching count, regulation of two battery voltages with two switches. Moreover, the inherent shoot-through protection enhances the converter's reliability. The proposed converter exhibits same working principle as that of conventional boost and buck converters. Consequently, the control system methodology remains consistent with that of separate converters, ensuring precise regulation of each output. The working principle, design analysis is discussed. To validate the theoretical analysis, detailed simulation results are presented.

On-board charger (OBC) and auxiliary power module (APM) are two major power electronic units in electric vehicles (EV). The OBC is the power electronic interface between the grid and the high-voltage (HV) battery. It has an AC-DC converter followed by an isolated DC-DC converter. The APM is an isolated dc-dc converter, is the interface between the HV battery and the low-voltage (LV) battery. The power density of such a configuration is poor due to the presence of multiple power electronic converters. In this paper, an integrated OBC and APM are designed to improve the power density. This solution employs a triple active bridge (TAB) converter, where the AC-DC converter is integrated as a current-fed structure within the converter. This current fed structure forms an interleaved boost converter which further reduces the size of the input inductor. Moreover, this converter has an in-built feature of second-order ripple power compensation (RPC) in the charge mode of EV, this reduces the number of power stages and improves the reliability of the converter. To analyze the performance of the proposed solution a 3.3 kW converter is designed and simulated using MATLAB/Simscape.

Phase Shifted Full Bridge (PSFB) DC – DC converter is a popular converter used in Electric Vehicles (EV) due to its salient features like high stability, Zero Voltage Switching (ZVS) property and simple design. In this paper, an ideal PSFB converter operating in Continuous Conduction Mode (CCM) is mathematically modelled using volt-sec and amp-sec balance equations and modelled using MATLAB / Simulink software with appropriate step size. Later, a single voltage loop control system is developed considering the sensor and Pulse Width Modulation (PWM) gains. The developed controller was tested for various conditions like output set points, load changes at high slope rates which are typical in EVs. In addition, the effect of ripple injection on the high voltage (HV) side of the transformer is observed on the Low Voltage (LV) for different frequencies. A simple PI controller was designed using the bode plot technique to regulate these disturbances.

In this paper, an ultra-versatile power converter based on a multi-winding flyback transformer is presented for EV application. Although the power converter concept, presented as Multi-cell Multi-port Bidirectional Flyback (M2BF), was initially proposed to interconnect several DC loads and/or sources, this paper proposes different configurations based on M2BF to interconnect and isolate different ports of an Electric Vehicle (EV), such as AC grid, High Voltage (HV) battery or Low Voltage (LV) battery. Numerous configurations are presented for each EV functionality, remarking the main differences and advantages respect to other configurations or SoA solutions. The main idea is to create a single power converter that performs the main functionalities of the EV, integrating several converters in a single circuit.

Multi winding-based converter for electric vehicle (EV) charging systems enables improved power density by integrating onboard chargers (OBC) and DC-DC systems. Triple Active Bridge (TAB) based topology is employed in this system for the integration of high voltage DC (HV DC) and low voltage DC (LV DC) converters, which allows electrical and magnetic integration of both converters into a single power topology. In EV charging system, HV DC power stage is employed for HV battery charging and LV DC power stage is employed for LV battery charging. A TAB converter used in the power stages of EV charging must be capable of functioning in various modes, such as charging, driving, and vehicle-to-grid. Each port of TAB will undergo simultaneous or independent activation during these modes of operation. In this work, a 7.4kW OBC and 2kW DCDC integrated system is designed, and functionality is analyzed with various modes of operation using MATLAB Simulink environment.

Electric vehicles (EVs) normally contain two kinds of batteries: high-voltage (HV) power battery and low-voltage (LV) auxiliary battery. The charging systems for these two kinds of batteries are normally independent and separate. This article proposes an integrated charging system that combines wireless power transfer (WPT) for the HV battery and the auxiliary power module (APM) for the LV battery. Part of the power electronics converters and compensation network is shared. The doubled-sided LCC topology is adopted with a constant-current output. An APM transformer is inserted in the constant-current branch to pick up power for the LV and also to guarantee the independent HV and LV outputs. The proposed system can work in two modes. One is WPT and APM where both the HV and LV batteries can be charged simultaneously. The other is APM where the HV battery supplies power for the LV battery. The integration of WPT and APM can improve the overall power density of the EV charging system and reduce the weight and cost.

The battery voltage $(\mathrm{V}_{\mathrm{bat}})$ is becoming higher in automotive applications for a higher efficiency power system. Accordingly, an ultra-low voltage-conversion-ratio (VCR) buck converter is in great demand. Previous ultra-low VCR buck converters use flying capacitors $( \mathrm{C}_{\mathrm{F}}\mathrm{s})$ and power switches between the battery and the inductor, as shown in Fig. 8.7.1 (top-right) [1–6]. In these topologies, $\mathrm{C}_{\mathrm{F}}\mathrm{s}$ reduce the voltage stress applied to switches by dividing the $\mathrm{V}_{\mathrm{bat}}$, which has four major weak points. First, because of the high $\mathrm{V}_{\mathrm{bat}}, \mathrm{C}_{F}\mathrm{s}$ and switches are used as high-voltage (HV) capacitors and LDMOSs, respectively, which are bulky and have larger parasitic components resulting in huge power loss compared to a low-voltage (LV) capacitor and CMOS. If compound semiconductors, such as GaN and SiC, are used, the power loss caused by switches can be reduced [1, 6], however, they are less cost effective than silicon devices. Second, previous converters have a problem of on-duty (D) range. Considering several types of battery and their safety margins in the vehicle, the converter is required to properly operate with a $\mathrm{V}_{\mathrm{bat}}$ range from 12V up to 60V. Previous converters can have the D either smaller than 0.1 or larger than 0.9 when they operate at this $\mathrm{V}_{\mathrm{bat}}$ range and an output voltage $( \mathrm{V}_{\mathrm{o}})$ of 1.2V, as shown in Fig. 8.7.1 (top-left), which makes the converter vulnerable to noise. Third, previous converters have another challenge for the line transient. In the automotive application, $\mathrm{V}_{bat}$ can abruptly vary because of external conditions, as shown in Fig. 8.7.1 (bottom-left). Since the voltage across each $\mathrm{C}_{\mathrm{F}}( \mathrm{V}_{\mathrm{CF}})$ is proportional to $\mathrm{V}_{\mathrm{bat}}$, an abrupt variation of $\mathrm{V}_{\mathrm{bat}}$ results in an abrupt change in $\mathrm{V}_{\mathrm{CF}}$. This induces a huge inrush current through the $\mathrm{C}_{\mathrm{F}}$ or unbalanced inductor currents causing fatal damage to the power switches. Lastly, previous converters suffer from a slow load transient response because the load current $(\mathrm{I}_{\mathrm{o}})$ is only provided by the inductor.

Electric Vehicles (EVs) are rapidly gaining popularity, leading to a growing demand for Integrated Onboard Chargers (IOBCs) that offer higher power density and cost efficiency. Conventional IOBCs typically use a two-stage multiport architecture for charging both high-voltage (HV) and low-voltage (LV) batteries, which limits power density and increases system complexity. This paper introduces a novel bidirectional multiport integrated onboard charger (MPIOBC) that integrates a single-stage, single-phase isolated AC-to-DC Triple Active Bridge (TAB) converter with the traction inverter and motor windings, to charge BV and LV battery simultaneously. The proposed MPIOBC ensures high-quality grid current at unity power factor and delivers smooth battery charging using traction inverter and motor winding as an active power decoupling. By eliminating bulky passive components and reducing the number of semiconductor switches, the system achieves a more compact and efficient design. Furthermore, an optimized modulation strategy is developed based on the charging durations of the HV and LV batteries. This strategy reduces circulating currents in the high-frequency transformer windings, thereby enhancing overall system efficiency.

This article introduces a new isolated, three-port, bidirectional DC-DC converter topology for EV APM. Through the manipulation of duty cycles and phase shifts between the LV and HV sides, the proposed topology achieves DCX at bridges 1 and 3, as well as near DCX at bridge 2, leading to a significant reduction in switching losses. Moreover, by controlling the phase shift between bridge 1 and bridge 2, the circulating current is halved, resulting in an overall 2% increase in efficiency compared to the existing configurations. A laboratory prototype of the three-port APM, featuring 140kHz operation and a wide voltage range of 400V to 840V has been implemented to validate the proposed structure.

This paper presents an isolated all-GaN resonant DC-DC converter using a HV ANPC and a LV full-bridge converter stage. The thermal characteristics and current limits as well as the switching behavior of the commutation cells of both converter stages are discussed. The ANPC-stage is tested with an output power of 1.8 kW operating as LLC converter, and the LV full-bridge is tested up to 27 A in a step-down DC-DC configuration. Measurement results of the resonant all-GaN LLC-converter are discussed and compared with simulation results.

The rapid evolution of electric vehicles (EVs) has necessitated advanced power conversion and battery management systems to enhance efficiency, reliability, and compactness. This project presents an integrated charging system for power and auxiliary batteries in EVs, employing a Dual Active Bridge (DAB) converter topology to achieve high-efficiency bidirectional power transfer between high-voltage (HV) and low-voltage (LV) batteries. The proposed system incorporates a shared magnetic coupler and compensation network for the wireless charging system (WCS) and the auxiliary power module (APM), minimizing component count and overall system weight. The design facilitates seamless operation in multiple modes, enabling both grid-to-vehicle and vehicle-to-auxiliary battery charging. Simulation and analysis are conducted using MATLAB/Simulink to evaluate steady-state and dynamic performance parameters, such as voltage regulation, current response, and Zero Voltage Switching (ZVS) efficiency. The integrated system demonstrates superior performance with reduced cost, improved power density, and enhanced energy management, thereby representing a viable solution for next-generation EV charging infrastructure.

This article presents a symmetrical bipolar output voltage-based DC-DC dual active bridge converter (DAB) using the triangular modulation (TRM) technique. In the proposed TRM, one arm of the high voltage (HV) side bridge is controlled using time-varying pulse width modulation (PWM), while the remaining arms of both the low voltage (LV) side bridge and the HV side bridge are controlled using time-invariant PWM. As a result of this switching strategy, the DC-DC DAB converter improves its soft switching performance, achieving 1) zero-current turn-on and turn-off for the devices operating on the LV side bridge. 2) zero-voltage turn-on for the devices on the HV side bridge operating with time-invariant PWM. 3) zero-voltage turn-on for the devices on the HV side bridge operating with time-variant PWM. The proposed TRM also ensures soft switching under all loading conditions with simple control, utilizing a single control variable that maintains a linear relationship with power. Simulation results, followed by experimental results of a scaled-down prototype of a 500 W system were developed using the TMS320F28335 for bidirectional electric vehicle DC charging system and EV-to-load applications, achieving an experimental efficiency of 94.7%.

Auxiliary power demand in battery electric vehicles continues to increase as manufacturers transition toward multi-low-voltage architectures that combine 48 V and 12 V buses to improve load distribution flexibility and overall system efficiency. This paper evaluates several auxiliary power module (APM) architectures in terms of scalability, efficiency, complexity, size, and cost for supplying two low-voltage buses (e.g., 48 V and 12 V) from the high-voltage battery. Based on this assessment, a cascaded APM configuration is adopted, consisting of an isolated dual active bridge (DAB) converter followed by a non-isolated synchronous buck converter. A multi-objective optimization framework based on the NSGA-II algorithm is developed for the DAB stage to maximize efficiency and power density while minimizing cost. The optimized 13 kW DAB stage achieves a peak efficiency of 95% and a power density of 4.1 kW/L. For the 48 V/12 V buck stage, a 2 kW commercial GaN-based converter with a mass of 0.5 kg is used as the reference design, achieving a peak efficiency of 96.5%. Dedicated PI controllers are designed for both the DAB and buck stages using their respective small-signal models to ensure tight regulation of the two LV buses. The overall system stability is verified through impedance-based analysis. Experimental validation using a DAB prototype integrated with a multi-phase buck converter confirms the accuracy of the DAB loss modeling used in the design optimization framework as well as the control design implemented for the cascaded converters.

The Dual-Active Bridge (DAB) topology offers various advantages in the applications of Electric Vehicle (EV) charging and Vehicle-to-Grid (V2G) power transfer, such as high efficiency, soft switching, modular structure, and bidirectional nature. This paper presents the DAB design topology for fast EV charging and V2G energy exchange, considering minimum battery deterioration. The HV and LV switches are designed to operate at zero-voltage switching (ZVS). A systematic loss analysis of the designed DAB converter is carried out for performance evaluation at various load conditions. The converter is then modeled using the Multi-frequency averaging (MFA) technique. A small-signal model is computed, and the transfer functions are obtained independently for the current and voltage control design. Constant-Current Constant-Voltage (CCCV) algorithm is used for battery charging. The battery discharge to the grid is carried out using Constant-Current (CC) mode. Simulation is carried out using the MATLAB-Simulink tool to validate the developed system.

On-board charger (OBC) and auxiliary power module (APM) are two major power electronic units in electric vehicles (EVs). OBC is the interface between the grid and HV propulsion battery, and the APM is the bridge connecting the HV system and LV system inside the EV. To save the cost and shirk the size, this paper proposed a three-port current-fed triple-active bridge (CFTAB) converter to integrate OBC with APM both electrically and magnetically. Compared with state-of-art integration approaches, the proposed converter features a simple structure, free of function-select switches, and fewer transformer turns. With the corresponding power decoupling method developed, the proposed topology also allows charging HV battery and LV battery simultaneously. Due to the current-fed nature, there is no need for large output capacitors, and much lower current stress is exhibited. In addition, an integrated prototype for 11kW/250V~450V OBC plus 3.5kW/10V~16V APM is developed to prove the superiorities of the proposed integrated charger.

In battery electric vehicles (BEVs), ensuring reliable auxiliary power is crucial for supporting essential functions such as communications, cooling systems, cabin air conditioning and emergency braking. Traditionally, 12V batteries have been widely used for auxiliary systems, but there is now a shift towards 48V systems, driven by the need for improved vehicle efficiency and enhanced performance. This transition is significant, especially for future medium and heavy duty BEVs, which are expected to use multiple low-voltage (LV) batteries to optimize power distribution. As part of an EU H2020 project, it is required to develop a digital twin model of the auxiliary loads power supply for an electric Truck. Hence, this research focuses on providing a proof of concept validation for an isolated DC-DC converter, known as the auxiliary power module (APM) through a high-fidelity model. This paper presents the design and evaluation of a single-input, multi-output cascaded APM topology for electric trucks, emphasizing its efficiency and performance. The integration of advanced switching technologies, including Si and SiC MOSFETs and GaN HEMTs, is highlighted for their potential to enhance APM functionality. A high-fidelity co-simulation model has been developed using PLECS-Blockset and MATLAB Simulink, demonstrating the APM's ability to achieve a peak efficiency of 98% at 10 kW in bidirectional power control between the high voltage (HV) bus and two LV buses.

To unlock the full potential of monolithic gallium nitride (GaN) power integrated circuits, this article explores the feasibility of developing efficient and reliable on-chip gate driving and level shifting solutions, which fundamentally facilitate the on-chip implementation of GaN power circuits. As results, a self-bootstrapped hybrid (SBH) gate driving scheme and its circuitry are developed, which achieve rail-to-rail dynamic gate driving in normal operation and robust static gate driving in large transient moments. Meanwhile, an auto-lock auto-break (A2) level shifting technique is proposed to convert the gate driving control signals from low-voltage (LV) to high-voltage (HV) domains, without requiring any p-type devices. This enables the on-chip operation of high-side power switches and makes synchronous rectification possible. On-chip temperature sensing is implemented to monitor junction temperature directly at low circuit complexity and power and cost overheads, facilitating thermal protection at high power density. Furthermore, on-die dead-time control is presented to optimize zero voltage switching (ZVS) for high efficiency. All the techniques and circuits are demonstrated in a monolithic asymmetrical half-bridge (AHB) power converter on a GaN-on-SOI process. It achieves direct 48V/1V dc–dc conversion with a maximum load current of 5 A and a current density of 1.1 A/mm2. Among the existing monolithic GaN power ICs capable of on-chip synchronous rectification, it achieves the shortest rising- and falling-edge gate driving delays of 11.6 and 14.0 ns. Despite running doubled numbers of on-chip power transistors and gate drivers, it only consumes 70-mW static power.

The rapidly developing electric vehicles (EVs) calls for improvement in the charging system for the high-voltage (HV) and low-voltage (LV) batteries in EVs. In the conventional EV charger, wireless power transfer (WPT), onboard charger (OBC), and auxiliary power module (APM) are three separate structures. This article proposes an integrated charger for WPT, OBC, and APM by sharing power conversion stages with the advantages of cost effectiveness and high-power density. The transformer of OBC can be seen as two strongly coupled coils, and the secondary-side coil can be loosely coupled with the transmitting coil of the WPT system, serving as a receiving coil. A transformer can be employed on the receiving side to integrate the APM with WPT. In this way, the receiving coil, the compensation network, and the power electronics converter can be shared. The integrated structure can work in three modes. In the first mode (wireless charging mode) and the second mode (conductive charging mode), the utility delivers power to the HV and LV batteries simultaneously. In the third mode (HV-LV mode), the LV battery is charged by the HV battery through APM. An experimental prototype is implemented to validate the proposal.

In electric vehicles (EVs), the wireless charging system (WCS) for the high-voltage (HV) power battery and the auxiliary power module (APM) for the low-voltage (LV) auxiliary battery possess some similar power conversion stages. This letter proposes an integrated solution for WCS and APM with the shared magnetic coupler, compensation network, and power electronics converter. The coupling coil for APM is incorporated with reverse windings so as to couple with the receiving coil but decouple with the transmitting coil of the WCS system. Thus, it forms magnetic couplers for APM. The proposed system can work in the mode where WCS and APM are in operation with power from the power grid, or in the mode where APM is in operation with power from the HV battery to the LV battery. The integration of WCS and APM can reduce its weight and cost and improve the power density of the EV charging system. The experimental results have proved the effectiveness of the proposal.

In order to solve the problem that the conducted interference voltage of a high voltage/low voltage (HV/LV) DC-DC converter for vehicles exceeds the standard CISPR25-2016, two different design methods of EMI filter for HV power supply were proposed. The first method is to design a wide-band EMI filter at the high-voltage input port of the DC-DC converter. It can achieve the insertion loss of 60dB within 150kHz-108MHz. Another proposed method is to design a PCB-level EMI filter based on the resonance peaks suppression. During the PCB-level EMI filter design process, a high frequency equivalent circuit model of HV/LV DC-DC converter of EV considering the parasitic parameters was established, and by establishing the transfer functions at key frequencies of 200 kHz and 2 MHz, the dominated parameters responsible for the over-standard points were determined. From simulation and experiment results, the filters designed by above two methods can effectively reduce the conducted disturbance and comply with the limits requirements in 150kHz-108MHz. What’s more, the PCB-level filter designed by the second method is smaller in size, only 1/5 of the filter size designed by the first method, lower in cost,and easy to be engineering.

To further reduce size, weight, and cost of power converters in an electric vehicle (EV), the dc-dc converter of onboard charger (OBC) and the auxiliary power module (APM) are electrically integrated. However, a key challenge of the electrical integration is to design a power-stage topology and its control which not only achieves high power density but also achieves independent regulation of voltage at each output port. In this paper, a new, isolated, three-port, bidirectional dc-dc converter topology and its control are proposed to achieve high power density and high efficiency in integrated OBC and APM for EV applications. The operation and control of the proposed converter is explained in detail in different operating modes. Finally, the design details about a 6.6 kW experimental prototype with three-winding transformer which integrates all the resonant inductors are provided. The experimental waveforms and measured efficiencies in charging mode, discharging mode, and EV running mode have also been provided. The measured efficiency in the charging mode at $\mathrm{V}_{\text{Bus}}=400\ \mathrm{V},\ \mathrm{P}_{\text{HV}}=4.5\ \text{kW},\ \mathrm{V}_{\text{LV}}=13.8\ \mathrm{V}$, and $\mathrm{P}_{\text{LV}} =300\mathrm{W}$ is greater than 97% at all HV battery voltage levels. The measured efficiency in the discharging mode at $\mathrm{V}_{\text{Bus}}=400 \mathrm{V},\ \mathrm{P}_{\text{Bus}}=4.4\ \text{kW},\ \mathrm{V}_{\text{LV}}=13.8\ \mathrm{V}$, and $\mathrm{P}_{\text{LV}} =300\mathrm{W}$ is greater than 96.9% at all values of VHV. Also, a peak efficiency of 96.5% is achieved in EV running mode at $\mathrm{V}_{\text{HV}} =380\mathrm{V}, \mathrm{V}_{\text{LV}} =13.8\mathrm{V}$, and $\mathrm{P}_{\text{LV}} =800\mathrm{W}$.

The use of electric vehicles (EVs) has grown notably in the last years and with it new challenges for power electronics have appeared. Since typically the main energy storage system in EVs consists of batteries, one of these challenges is the efficient and reliable management of power flows in charging/discharging mode. This paper presents an electrical and thermal modelling of a three-level buck-boost DC-DC converter (TLBBC) with semiconductors based on gallium nitride (GaN) technology. Also an active thermal control (ATC) scheme to mitigate the thermal stress in the semiconductor is proposed, together with control schemes for DC-link voltage and voltage balance between capacitors in the TLBBC. The TLBBC is designed to operate in a boost mode at rated power of 25 kW, using a parallel design with GaN semiconductors. Proposed control schemes are implemented using linear controllers. Finally, comprehensive simulation results confirm and validate the proposed control schemes.

One of current challenges in high-density electric vehicles (EVs) is the efficient thermal control of power converters and the reliable management of power flows in motoring/breaking mode for the battery bank. In this line, this paper presents an Active Thermal Control (ATC) scheme to regulate thermal stress in Gallium Nitride High Electron Mobility Transistors (GaN HEMTs) devices of a three-level bidirectional buck-boost DC-DC converter (TLBBC) as a power interface between battery and motor inverter. The TLBBC is designed to operate at a rated power of 20 kW as part of a modular system, by using parallel GaN devices. Proposed control schemes are implemented using systematic linear control design. Finally, the system is simulated and tested for a Mission Profile-Oriented (MPO) based on Highway Fuel Economy Test (HWFET) in order to validate the proposed control schemes.

Electric vehicles are attracting great attention with their 48V electrification system. In this paper, the design of a two-stage 400V/48V automotive DC-DC converter based on PCB magnetics is presented. A two-phase buck converter with a coupled inductor is used as the first stage to perform voltage regulation and guarantee good load transient performance. The second stage is an LLC resonant converter with a matrix transformer which provides isolation and behaves as a step-down DC transformer (DCX). The switching frequency is pushed to 500kHz to help reduce converter size and weight. By pushing the operation to high frequencies, the windings of the transformer of the LLC converter and those of the coupled inductor of the buck converter are integrated and built into the PCB. This not only improves the power density, but also minimizes the use of labor-intensive components/processes to enable truly automated manufacture. The thermal management for such converters is especially challenging due to the harsh environments it is situated in. This is accomplished using a custom-engraved aluminum baseplate to provide low thermal resistivity and increase converter reliability. The converter can achieve an efficiency of 97% and a power density of 5 kW/L.

A Continuous-Control-Set Model Predictive Control (CCS-MPC) proposed for DC-DC converters for EV powertrains based on Gallium Nitride High Electron Mobility Transistors (GaN HEMTs) devices is presented in this work. The CCS-MPC allows full control of system states by adopting a multi-objective control approach, ensuring optimal power exchange between the DC link bus and a battery. The main contribution of this paper is a systematic implementation of the thermal-management of power devices by including an Active Thermal Control (ATC) in the context of CCS-MPC. The secondary contribution is to verify the proposed method in a Two-Level Buck Converter (TLBC), used in EV applications for e.g. auxiliary battery charging interfaces. Finally, simulation results are presented to verify the performance of the proposed control scheme.

This paper presents the thermal characterization of Gallium Nitride (GaN) transistors based Quad-Active-Bridge (QAB) converters with a novel stationary liquid immersion cooling technique. This QAB multiport converter interconnects photovoltaic (PV) panels, battery energy storage (BES), electric vehicles (EVs), and DC grid. To provide a cost-effective cooling solution with improved dielectric insulation capability, the GaN QAB converter is immersed into a dielectric coolant with no pump and heat exchanging units. Multi-physics analysis is conducted to characterize the thermal performance of the stationary immersion cooled converter, which shows satisfactory thermal management capability compared to the conventional air cooling methods. The GaN QAB converter's ultra-compact footprint complements the cooling benefits, supporting reliable high-frequency operation. The findings confirm stationary immersion cooling as a viable solution for compact, high-performance GaN power converters in emerging applications such as electric vehicles and data centers.

GaN is an excellent selection for implementation in the transportation industry due to its high switching frequency, high power density, and high breakdown voltage. The aim of this paper is to develop a one-sided DC/DC 48V/12V GaN-based Buck converter that is simple to design and manufacturing for laboratory experiments and testing, revealing its advantages over double-sided converters. Three different layouts are suggested and compared in this investigation in order to optimize the power loop layout by minimizing its parasitic elements; those latter are extracted using Ansys software “Q3D tool” and then included in an electrical model in the waveform viewer software “LTspice” to evaluate their impacts on the switching node signal “Vsw” of the half bridge configuration. An examination of current density and pathing in each layout is also presented in this study. Simple calculations are performed for thermal management, which end up resulting in the selection of a heatsink as a cooling solution. At 1 MHz cut-off frequency, the layout chosen have a power loop inductance of 0.73nH, which results in decreased ringing phenomena.

The lateral structure of gallium nitride (GaN) semiconductors enables monolithic integration of logic and power devices, which offers promise to miniaturize bulky converters into a compact package. However, the concentrated heat that arises from this dense integration can locally exceed 1 kW/cm2, which surpasses the limit of current thermal management technologies. In this article, we demonstrate the potential of integrating in-chip microfluidic cooling directly on GaN power integrated circuits (ICs), together with additively manufactured packaging, to provide efficient thermal management, and achieve ultrahigh-power densities. A prototype power module and a 0.44 kW 48 V–24 V dc--dc converter were realized in a compact 32nd brick form factor to demonstrate its potential. Our results show a 14-fold reduction in thermal resistance and a four-fold increase in the total output power compared to heat-sink and fan cooling. An outstanding 78 kW/l was achieved, together with an increase in power conversion efficiency, surpassing 95%. By removing thermal limitations from power IC design, and enabling highly integrated topologies combined in a single liquid-cooled chip, this work paves the way for more efficient and highly compact power conversion in the future to support the electrification of our society.

Megahertz switching frequencies in converters significantly reduce the size of passive components, enabling high power density. However, these frequencies also introduce operational challenges, such as the semiconductor device reliability, thermal management, magnetic design and electromagnetic interference. This paper discusses a dc-dc converter operating at 1 MHz and its associated design challenges. The relationship between a GaN device on-resistance, junction temperature and losses in scenarios where the converter operates beyond its nominal design specifications is analyzed. Additionally, a PCB-based inductor is fully characterized and the parasitic effects of PCB traces are examined for a 1-MHz, 1-kW application. Finally, the conducted and radiated emissions of the converter are addressed, supported by simulation and hardware experimental measurements.

V GaN-based DC-DC converters are widely used in electric vehicles, data centers, and renewable energy systems for their high-power density and low transmission loss. However, at high switching frequencies, inaccurate deadtime control can lead to reduced efficiency and potential device failure. This work proposes a $0.25 \mu \mathrm{~m}$-CMOS-based deadtime control circuit at 1 MHz to improve the performance of a 48 V -to- 24 V GaN buck converter. The design integrates a zero-voltage comparator with CMOS logic circuits to achieve reliable, compact deadtime control. A buck converter with a bootstrap gate driver was built to verify the approach. Results confirm a stable 24 V output voltage. Fullsystem simulations indicate an overall minimum deadtime of 22 ns at 2.6 A load current, with the highest efficiency reaching 95% across load conditions. This approach not only simplifies the circuit design but also achieves high efficiency and short deadtime, making it highly valuable for research and application in highfrequency GaN converter systems.

Fixed dead-time controlling strategy is widely adopted in conventional converter design, while it suffers from the potential issue of simultaneous conduction under different loading conditions. This work aims to adaptively optimize the dead-time at the monolithic integration level through simulation software, Advanced Design System (ADS). In a 48 V GaN buck converter, the sub-20-ns adaptive low-side dead-time control and high-side dead-time control are achieved at 1 MHz operation frequency. The proposed dead-time control circuit exhibits a maximum efficiency up to 91.4 %, facilitated by the adaptive and self-generated dead-time design.

No abstract available

To achieve a fast load transient response time in a switching power converter, constant on-time (COT) hysteretic mode control has been reported recently. However, due to the limitations on fixed on-time and mandatory minimum off-time, sluggish response and large voltage over-/undershoot are severe during extreme load transient scenarios. This paper presents a load transient enhance scheme which achieves adaptive on-time (AOT) transient response promptly and within one switching cycle, through instantaneous load change (∆IO) sensing technique. Based on the AOT control, a single-stage Gallium Nitride (GaN) based DC-DC converter is designed. Because a GaN switch inherently has no body diode and thus shows a high reverse conduction voltage, the efficiency is degraded with excessively long dead time (tdead). Accordingly, a sample-and-hold (S/H) based closed-loop dead time control is proposed to regulate tdead adaptively according to instantaneous input voltage (VIN) and IO. The converter is implemented using a 0.35-µm high voltage (HV) BCD process, accomplishing the DC-DC voltage conversion from 40 to 1.2V at 5MHz. In response to load steps between 0.5A and 10A, it achieves a 49mV/29mV VO undershoot/overshoot within one switching cycle. Thanks to the adaptive dead time control, the efficiency is improved by 4.8% at light load and 1.5% at heavy load, respectively, with a peak value of 89.5%.

No abstract available

Advanced packaging technologies in Wide band gap devices like GaN avoid wire bonds thereby making the solder joints more susceptible to thermo-mechanical fatigue. To limit the thermal cycling induced failures, an active thermal control scheme using a two step gate driver for a buck converter is presented in this paper. In contrast to the active thermal control techniques employing variation of switching frequency, this method does not alter the converter operation point. A simple temperature control algorithm which actively varies the device losses is proposed. The effectiveness of the control scheme has been validated through experimental results.

A configurable quad-slope 70V GaN gate driver is designed to optimize the EMI noise and to simultaneously improve the level shifter’s robustness based on dV/dt detection and delay compensation. A three-mode level shifter with enhanced negative voltage tolerance (ENVT) and commonmode noise energy recovery is firstly proposed to adapt to different operating conditions. The measured results show that the high-side bias of the level shifter (VLS) in different modes is always larger than the supply voltage of the high-side gate driver (VB) when signal transmission, achieving different ENVT capability. The delay of dV/dt detection is eliminated by using the proposed circuits of double-edge self-triggered delay compensation. The amplitude of VSW ringing at different gate control modes are compared, showing that the proposed quad-slope control is able to suppress the ringing amplitude by 42.3% with RON=5Ω.

Compared with traditional Si mosfets, gallium nitride high electron mobility transistors (GaN HEMTs) have faster switching speeds. During the turn-off process of GaN HEMTs, the rapid decline of current causes serious drain-source voltage overshoot and electromagnetic interference, which limits the reliability and application scenarios. This article proposed a GaN HEMT active gate driver based on magnetic coupling closed-loop control (MCCLC) to address these issues. In MCCLC, coils arranged near the power loop can accurately provide di/dt feedback of the power side under completely electrically isolated conditions, which is more reliable than traditional methods. The proposed method does not require additional control signals and can segmentally optimize the gate drive voltage during turn-off transients. A double-pulse test (DPT) based on the GS66508B verifies the effectiveness of MCCLC at 400 V/30 A. Compared with CGD (conventional gate driver), the overshoot of the drain-source voltage decreased by 51.8%, the average slope of current decline was reduced by 24.2%, and the high-frequency component of the drain current at approximately 80 MHz was reduced by 11.2 dBμA. MCCLC has a 36.9% lower turn-off loss than CGD with a larger gate drive resistor when they have almost the same voltage overshoot.

No abstract available

This letter proposes a novel dual-NMOS gallium-nitride gate driver integrating an active bootstrap (BST) and a high common-mode transient immunity (CMTI) capacitive level shifter (LS). Compared to conventional PMOS-based BST circuits requiring extra LSs, the proposed design utilizes bidirectional NMOS BST switch pairs with dedicated on-off control circuit, providing reliable floating gate voltage with reduced on-chip area. The capacitive LS achieves theoretically infinite CMTI by isolating differential-mode logic signals from common-mode noise through current-mirror-based edge-detection and noise isolation. Furthermore, the dual-NMOS high-side buffer enables continuously adjustable dV/dt via adaptive Miller plateau detection and configurable gate charging currents, reducing switching losses and voltage spikes versus fixed gate-resistor drivers. Experimental results demonstrate a peak efficiency of 91.8% in a 12-to-1.8 V conversion and 4.6% efficiency improvement under 48 V input and 2 MHz switching frequency, validating its potential for high-frequency, high-density power applications such as automotive dc–dc converters.

Aiming at electromagnetic interference (EMI) suppression for multiple applications, this article demonstrates a 10-MHz 4- to 40-V ${V _{\text {IN}}}$ , gallium nitride (GaN)-based buck converter with multiple EMI reduction techniques. A Gaussian switching scheme is realized on chip for the first time for GaN power switches to effectively reduce the conducted EMI level in the high-frequency domain. Meanwhile, spread-spectrum frequency dithering (SSFD) technique is adopted to compress the spurious switching noise in the low-frequency domain. To handle high-speed Gaussian switching, a feed-forward segmented driving scheme is proposed to generate precise Gaussian trajectories. The Gaussian slopes are reconfigurable to enable optimization of the power efficiencies for different EMI standards. Implemented in a 180-nm BCD process, the presented GaN-based buck converter reduces the EMI noise by 35.8 and 38.7 dB at 10 and 100 MHz, respectively. From 100 to 250 MHz and from 250 to 400 MHz, the measured peak EMI noise is reduced by 20 and 30 dB, respectively. While the EMI is greatly reduced, the maximum power efficiency is 85.2%, comparable to that of other state-of-the-art GaN gate driving schemes.

Due to the complex structure and unique characteristics of cascode GaN devices, the traditional gate driver cannot satisfy or take the full advantage of the cascode GaN. This paper presents a SPICE modeling method that takes into account circuit layout and device parasitic to analyze switching behavior under the gate driving parameters, then a gate driver(GD) is proposed, which consisting of separated turn on and turn off path by different flying capacitors and gate resistors to control gate loop impedances at different transient stage. Compare with the traditional gate driver, the proposed GD can accelerate the switching speed and suppress the overshoot, oscillation and electromagnetic interference (EMI) produced by high di/dt and dv/dt while reduce the power loss. The experiment validated the effectiveness of proposed GD.

The proposed low input current ripple (LICR) switched-capacitor (SC) hybrid converter effectively minimizes input current ripple by incorporating a precompensation active biasing electromagnetic interference (EMI) filter (PABEF), addressing EMI issues in automotive applications without requiring large external components. In addition, the current-modulation gate driver (CMGD) helps suppress conducted EMI noise at high frequencies. As a result, the LICR achieves a 74% reduction in input current ripple, EMI noise attenuation of 32 dB at low frequencies and 5 dB at high frequencies, and a peak efficiency of 93.3% at <inline-formula> <tex-math notation="LaTeX">$V_{\mathrm { O}}$ </tex-math></inline-formula>/<inline-formula> <tex-math notation="LaTeX">$V_{\mathrm { IN}}{=}1.8$ </tex-math></inline-formula>/24.

The active gate driver (AGD) reduces instability and electromagnetic interference (EMI) resulting from rapid switch-node slew rates in the half-bridge driver of gallium nitride (GaN) high electron mobility transistors (HEMTs) while maintaining the switching speed. This paper seeks to improve the effectiveness of the AGD method by integrating the influence of load current on the voltage slew rates. Consequently, we present a tri-current AGD prototype that employs a 4-bit current-based DAC to accurately regulate the drive current during the Miller Plateau (MP) phase. By measuring the load current, we implement the feedback control of the MP drive strength via a digital loop on the FPGA. Experimental measurements validate that the suggested AGD circuit sustains an overshoot voltage of 0.3V/A when the load current fluctuates between 0.8A and 4A and achieves a driving speed of 25.6% faster than the conventional methods.

Automotive headlamp and/or taillamp tend to integrate a high number of LEDs (up to 30 LEDs in series) for sequential turn signal light. As the LEDs are turned on/off sequentially, the output voltage across the LED string $(V_{{OUT}})$ can be below, equal to, or above the input battery voltage $(V_{{IN}})$ which also experiences a large transient from 4 to 60V. To achieve accurate and stable LED current regulation over such a wide operation voltage range, high-voltage buck-boost converters are desperately demanded [1] –[4]. Although high- switching-frequency $(f_{sw})$ solutions have been explored as in [4], [5], the stringent thermal and size limitations imposed by automotive applications have made it increasingly challenging to continue using silicon-FET-based converters. Gallium-Nitride (GaN) FET, which offers a $5\times$ lower capacitance and nearly zero reverse recovery to enable an efficient high-voltage operation at high $f_{SW}(\gt 2MHz)$, has been proven to be a very promising device in this scenario [5]. However, severe electromagnetic interference (EMI) due to high fsw operation and complicated bootstrap GaN gate driving become very challenging for GaN buck-boost LED drivers in automotive applications.

In this paper, a CMOS gate driver in $180\mathrm {n}\mathrm {m}$ technology is presented. The gate driver implements an integrated and independent ultra-fast $\mathrm {d}\mathrm {V}/\mathrm {d}\mathrm {t}$ control circuit dedicated to manage switch-on transients for $\mathrm {G}\mathrm {a}\mathrm {N}$ HEMT technology. In order to mitigate a detrimental effect in EMI spectrum for wide bandgap transistors, a novel method to reduce $\mathrm {d}\mathrm {V}/\mathrm {d}\mathrm {t}$ without increasing so much switching losses is proposed. A comprehensive benchmark with the classical method is also presented, where the gate driver resistance is typically adjusted. Simulations are conducted to show the feasibility of the proposed method and the amount of switching energy that can be saved. Time responses of a feedback loop lower than $200\mathrm {p}\mathrm {s}$ are expected. The preliminary characterization of the integrated CMOS circuit is shown.

Gallium-nitride (GaN) HEMTs enable compact and efficient power converters, but paralleling multiple devices increases sensitivity to nanosecond-scale timing errors and parasitic inductances. This paper investigates four Infineon CoolGaN IGOT60R070D1 devices connected in a half-bridge configuration on the EVAL_HB_ParallelGaN board. Propagation-delay spread, dead-time requirements, and current-sharing behavior are characterized using double-pulse tests and continuous PWM operation. The study focuses on a simple hardware modification of the gate loop where the common-mode chokes (CMC, Murata SRF2012-361YA) were removed and replaced with short copper jumpers. This change reduces loop inductance and improves Kelvin-source routing. Tests were performed at a 35 V DC link in order to evaluate timing effects and current balance without introducing highvoltage switching stress during the initial evaluation phase. Results show reduced turn-on and turn-off delay spread as well as improved current sharing. The findings provide practical guidance for gate-driver impedance selection or dead-time tuning for both hard- and soft-switched GaN converter stages. These recommendations are relevant to high-density designs such as data-centre power supplies, automotive chargers, and renewable-energy inverters.

This paper focuses on the critical considerations and practical challenges in gate driver design for non-isolated DC-DC converters using gallium nitride (GaN) devices. We discuss the circuit-level operation issues when driving GaN switches, and further review the advanced design techniques of the essential building blocks, including on-chip bootstrapping circuit, over-voltage protection, false-switching prevention, EMI noise suppression, and efficiency optimization by adaptive driving. Comparative feature analysis in specific performance aspects is demonstrated, aiming to provide a design reference regarding the requirements on integration feasibility, device safety, operation reliability, and loss alleviation.

Wide-band-gap power devices hold great promise for creating power-conversion systems that are smaller, faster and more energy efficient than silicon power devices. Benefiting from smaller parasitic capacitors and superior conductive characteristics of gallium-nitride (GaN) transistors, the switching frequency $(\mathrm{f}_{SW})$ of power converters can soar to several or even dozens of MHz. Meanwhile, the power efficiency can be significantly improved. However, increasing switching speed leads to large values of di/dt and dv/dt during turn-on transition period, which results in several reliability issues. The turn-on dv/dt will cause a displacement current to charge the $\mathrm{C}_{GD}$ Miller capacitance of the complementary switch in half bridge, inducing false turn-on or even shoot-through, and the isolation structure will be influenced by the common-mode transient noise generated by dv/dt. In addition, EMI noise and gate oscillation will be even more severe as the values of di/dt and dv/dt increase.

With the increase of switching frequency, high power density converters require extremely urgent requirements for low power loss, high ring suppression and EMI optimization for the drivers. This work proposes a novel resonant gate driver designed for high frequency E-mode GaN HEMT power devices that can flexibly online configure the power device's turn-on and turn-off dV/dt. DV/dt can change by more than 6 times with the help of bias of auxiliary transistors, respectively. The calculated data is provided to optimize the efficiency and EMI noise. Meanwhile the topology can reduce the sensitivity of gate parasitic inductance to avoid incorrect operation. These operations of the proposed resonant gate driver are verified by utilizing 100V GaN HEMT.

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Gallium nitride (GaN) high electron mobility transistors (HEMTs) are promising power devices due to their excellent characteristics. However, GaN HEMTs have vulnerable gates that are susceptible to noise and voltage spikes, limiting their implementation in power converters. This paper presents a GaN HEMTs half-bridge driver with bandgap reference comparator clamping (BGRCC) and dual level shifters (DLS) for high switching frequency automotive applications. The BGRCC scheme can adaptively clamp the bootstrap rail voltage at an appropriate level with acceptable voltage ripples, which guarantees the safety of high-side GaN HEMT. Meanwhile, DLS scheme is applied in both the high- and low-side driving path to effectively drive the GaN HEMTs with low propagation delay and high dv/dt immunity. The proposed driver is fabricated in 0.18 μm high voltage bipolar-complementary metaloxide semiconductor (CMOS)-double-diffused metaloxide semiconductor (DMOS) process and can support 2–10 MHz operating. The functionality and performance are verified by experimental results. A buck converter utilizing this driver with GaN HEMTs can achieve maximum efficiency of 91.58% with quite electromagnetic interference behavior in the 16.5-W output power rating when operating at 2 MHz, which is superior to conventional silicon-based power converters and suitable for automotive applications.

For future automotive applications, the growing demand for tiny, high power density and fast dynamic response is putting more pressure on power converters, where Gallium nitride FETs have proven to be promising devices [1]. However, for high conversion-ratio GaN power converters, the floating power rail control of half-bridge gate driver and low FOM/high-reliability level shifter (LS) pose a big challenge when increasing switching speed dV/dt and frequency (smaller Ton, min and Toff, min). Charging saturation and over-voltage protection of the bootstrap power supply, as well as common-mode transient immunity (CMTI)/transmission delay/power consumption of LS may introduce efficiency degradation and significant reliability issues.

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The gate driver parasitic loop inductance and EMI characteristics of a 1-MHz, 1-kW GaN buck converter are investigated. The parasitic effects contributed by PCB traces are critical in higher-power and MHz-frequency operational systems. These parasitic inductances lead to voltage overshoots and ringing, which is a primary cause of EMI. Therefore, the power and driving loops within the layout were designed to minimize loop inductances. The parasitic inductances, extracted through finite element analysis (FEA) tools, were modelled within LTspice to assess the impacts of the designed layout. The gate-to-source voltage waveform from the hardware exhibits slightly higher voltage spikes compared to the LTspice simulation. The conducted noise measured in the FEA was over the standard electromagnetic compliance limit by 10 dBuV in the frequency range of 1 MHz to 5 MHz. Adding a filter to the input side of the converter will improve the conducted emissions.

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This paper investigates the circuit application of co-packaged Gallium Nitride (GaN) devices under high-frequency conditions, presenting a comparative analysis against discrete solutions. The co-packaging technology integrates two gate drivers and two GaN power high-electron-mobility transistors (HEMTs) into a single package. Unlike conventional discrete designs, which are susceptible to interconnect parasitics, this co-packaged approach significantly reduces inter-chip parasitic inductance and capacitance by minimizing interconnect lengths and optimizing the layout. This reduction in parasitic elements leads to faster switching transitions, lower ringing and overshoot, thereby enhancing switching performance and decreasing electromagnetic interference (EMI). To demonstrate these benefits, a 1.5 MHz, 330 W LLC converter with a 400 V DC input and a 20 V DC output was constructed and tested using diode rectification. Experimental measurements indicate that the co-packaged GaN solution reduces the total turn-on and turn-off energy losses by approximately 20% compared to the discrete implementation. The measurement results show a peak efficiency of 92.8%, validating the effectiveness and reliability of the co-packaged GaN solution for high-frequency resonant power conversion applications.

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Many applications including automotives demand DC-DC power converters that can cover wide input range with improved power efficiency. This paper presents a 4–40 V input, Gallium Nitride (GaN) based non-inverting buck-boost converter incorporating several methods to improve power efficiency. It employs a new floating-ground three-state four-switch topology along with a pre-charge gate driver for the low-side GaN switch, a Dual Duty-Cycle Controller (DDCC) and an Inductor Peak Current (<inline-formula> <tex-math notation="LaTeX">$I_{LPEAK}$ </tex-math></inline-formula>) adjusting Module (IPCM). The floating-ground technique alleviates the voltage stress on the high-side power switch and minimizes the inductor current ripple <inline-formula> <tex-math notation="LaTeX">${\Delta I}_{L}$ </tex-math></inline-formula>, resulting in reduction of both switching power loss and conduction power loss. Additionally, the floating-ground topology together with a pre-charge gate driver for the GaN switch achieves a precise pre-charging time duration, preventing reverse conduction during the switch dead time. Consequently, the converter optimizes the power efficiency especially in the buck-boost mode (for <inline-formula> <tex-math notation="LaTeX">$V_{IN}$ </tex-math></inline-formula> of 10–14 V in design). The DDCC determines precise duration of each state for the three-state operation and maintain seamless transition across different modes. The ICPM enables adjusting <inline-formula> <tex-math notation="LaTeX">$I_{LPEAK}$ </tex-math></inline-formula> through indirectly sensing <inline-formula> <tex-math notation="LaTeX">$I_{L}$ </tex-math></inline-formula> and the output voltage <inline-formula> <tex-math notation="LaTeX">$V_{OUT}$ </tex-math></inline-formula> followed by the DDCC. With the proposed techniques, the reverse conduction of the low-side switch is minimized, and a 2% peak efficiency improvement is achieved in the buck-boost mode. Operating at 2 MHz covering 4–40 V input to a 24W (12 V and 2 A) output, this buck-boost converter achieves a peak efficiency of 92%.

The increasing demand for high efficiency and high power density is impelling converters and devices to a limit. Wide-band gap devices, such as GaN HEMTs, have the ability to increase power density without affecting power losses. In this context, multiport isolated converters based on multiwinding transformers (MWT) are able to increase the efficiency and power density of the converter, in particular for low-power applications. For this reason, this paper proposes a topology, which is particularly useful for high-current applications, such as those required by onboard systems in electric vehicle (EV) applications. Moreover, this paper evaluates the different multiport resonant converters taking into account their efficiencies, operation under distinct voltage levels, and parameter mismatches. Finally, the effectiveness of the converter is validated by using analytical simulations and experimental results. For this purpose, a hardware demonstrator was implemented.

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: Realizing both of compact and low energy consumption is technical issue on development of electricity-rich automotive subsystems. In the present work, a 12-V/48-V dual-voltage subsystem using three-port DC/DC converter cells is proposed, and the high power density cell design is studied to achieve ultra-compact subsystem in hybrid-electric-vehicle. A 500 W, 400 kHz prototype is developed with GaN FETs, and its efficiencies are evaluated. The prototype achieves power density of 28 W/cm 3 at rated power, and its efficiency is measured more than 91% over a wide output power range, with a maximum efficiency of 93.7%.

With the advances in artificial intelligence, devices are becoming more intelligent and power hungry. The 48V-to-1V converter, which offers a promising solution to the high-power density data center and automotive applications, is quickly gaining the interest of researchers [1 –4]. The prior state-of-the arts, however, mainly employ Gallium Nitride (GaN) or other discrete switches for 48V-to-1V design, which increases costs and hurts power density. In this work, a 12-level series-capacitor converter adopting on-chip switch and GaN hybrid power conversion is proposed. By exploiting the benefits of low-voltage on-chip transistors, this work reduces component count, increases switching frequency and improves power density.

This paper presents the optimal design of a wide-input range, dual-output 10 W isolated active-clamp flyback (ACF) gate-drive power supply (GDPS) for high-temperature automotive applications. Detailed analysis and comparison between Critical Conduction Mode (CRM) and Continuous Conduction Mode (CCM) are provided to select the operating mode. A printed-circuit-board-embedded (PCB-embedded) transformer is carefully designed and it significantly improves the power density of the power supply. A 10 W, GaN-based converter prototype switching at 1MHz has been developed to demonstrate the attained power density (53.2 W/in3), peak efficiency (89.7%), input voltage range (8.5 V to 28 V), maximum operating ambient temperature (105 °C at 8.5 V and 115°C at 28 V), and transformer input-output capacitance (9.7 pF).

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This paper presents an isolated step-sown DC-DC converter using GaN power device for automotive applications. The works for a power supply from a high voltage main battery with 200V to low voltage auxiliary battery with 13.6V in hybrid electric vehicle. A LLC converter is known as isolated DC-DC converter with high-efficiency. However, when input and/or output voltage considerably fluctuates, efficiency of a LLC resonant converter becomes worse. In order to solve this problem, a DC-DC boost-up converter to mitigate efficiency deterioration for the input and/or output voltage fluctuation is added to a LLC resonant converter. Generally speaking, an additional circuit, the boost-up chopper in this case, also deteriorates the total system efficiency. To avoid the efficiency degradation, discontinuous current mode control and GaN power devices are applied to the boost-up chopper. The DC-DC boost-up converter experimentally achieves 99.03% of conversion efficiency at nominal output so that it has no effect on the total system efficiency. Even though adding a DC-DC boost-up chopper to the LLC resonant converter, a power density expected to 10 W/cc.

This article proposes a multifunctional onboard charger (MOC) for electric vehicles (EVs) that facilitates main battery charging (MBC) from a single-phase grid. It can also feed power to single-phase load or back to the grid, and as an auxiliary power module (APM), supplying low-voltage dc (LVDC) power to the vehicle's auxiliary system. The proposed charger is a two-stage converter wherein the first-stage consists of front-end Totem-pole power factor correction (PFC) circuit with an integrated ripple power compensation (RPC) circuit to absorb the second harmonic ripple power. The second-stage is a dual active bride (DAB), used to control the power to/from the main battery. To facilitate the APM mode of operation, the first-stage circuitry is reconfigured to form an interleaved buck converter to supply high current to the LVDC bus. In addition, the dc conversion ratio of DAB is maintained near unity by adjusting the winding configuration of the transformer ensuring soft-switching in all the operating modes. The high dc link voltage requirement of the integrated RPC is addressed by using a novel RPC control methodology, thereby facilitating the use of 650 V GaN switches in the converter. Detailed simulation studies are carried out to predict the performance of the converter for all the modes of operation, and these results are experimentally validated on a 7.2 kW laboratory prototype.

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On-board battery chargers are a key component of electric vehicles of all types. Conventionally, they may be used to recharge a vehicle’s battery pack, but as they are connected to the grid, they can also be used to provide ancillary grid services, such as reactive power support and longer-term battery-to-grid backup. On-board chargers also represent a potentially significant portion of a vehicle’s weight and can take up considerable volume. This paper discusses the design and implementation of a high power density Level II charger converting between 400 VDC and 240 VAC, utilizing two interleaved flying-capacitor multilevel converter stages combined with a full H-bridge unfolder or active rectifier. The focus of this work is the ac-dc/dc-ac power stage, with the goal of high efficiency and power density. Thus, power factor correction (PFC) control and twice-line-frequency buffering are not discussed or implemented in this work. Experimental results show a peak system efficiency of greater than 98.9%, a power output of 7 kW, and an effective switching frequency at the inductor switch nodes of 720 kHz.

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The research work proposes a Gallium Nitride (GaN) based dual active bridge (DAB) converter for electric vehicle (EV) charging applications. The wide bandgap semiconductor device, GaN is implemented in the DAB topology of an Isolated Bidirectional DC-DC converter (IBDC). GaN-based DC-DC converters lead to higher efficiency, smaller size, faster charging, and reduced heat generation improving the overall performance of the EV charging system. The performance characteristics of GaN based DAB converter is analyzed both in simulation and hardware for EV charging application. The same analysis is extended to a Si based DAB converter and comparative results are presented. A 14.25 kW GaN based DAB and 10.5 kW Si based DAB is designed and evaluated using LTspice XVII software and a scaled-down prototype of 0.612 kW GaN based DAB and 0.25 kW Si based DAB is presented for experimental validation. Result analysis under similar operating conditions indicated an improvement of 36% more output power transfer on the GaN based DAB over the traditional Si based DAB. The developed prototype showcased improved levels of power, voltage, and current under same operating conditions. The power transmission in the developed DAB based IBDC topology is controlled using the single-phase-shift (SPS) control strategy.

The research work proposes a gallium nitride (GaN) based isolated bidirectional DC-DC (IBDC)-triple active bridge (TAB) based multi-port converter (MPC) for electric vehicle (EV) charging. The proposed GaN IBDC-TAB based MPC incorporates one input port (Port 1) and two output ports (Port 2 and Port 3) for charging, implying the use of fewer components compared to a conventional dual active bridge (DAB) charging system. The output ports can be operated individually in single active bridge (SAB), Dual active bridge (DAB), and TAB modes. A 12 kW GaN IBDC-TAB based MPC converter is designed for simulation study using LTspice XVII software. In the TAB mode of operation, output Port 2 designated for Level-1 (L-1) charging produces 1.5 kW, and output Port 3 designated for Level-2 (L-2) charging produces 10.6 kW. The maximum efficiency of 98.87% is obtained in simulation for the MPC converter in TAB mode. For experimental validation, a 0.91 kW prototype is presented with Port 1, Port 2, and Port 3 voltages as 230 V, 120 V, and 200 V respectively with the considered switching frequency of 100 kHz. The single-phase-shift control strategy is implemented for controlling the transmitted power in the proposed GaN IBDC-TAB converter.

The advent of Wide-Bandgap (WBG) semiconductors, e.g., Silicon Carbide (SiC) and Gallium Nitride (GaN), power electronics E-drive converters are projected to obtain an increase in power density as $\sim 2\mathrm{x}$ for SiC devices and ~4x for GaN devices, which demand detailed thermal modeling and analysis of power semiconductors and cooling systems. This paper has proposed high-fidelity (HiFi) modeling of bidirectional DC-DC converter coupled with liquid cooling system providing detailed information with higher accuracy and less complexity to determine performance during conceptual modeling in electric vehicle drivetrain with minimum testing and development effort.

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This paper proposes a high-efficiency bidirectional AC/DC converter utilizing a totem-pole configuration integrated with an Artificial Neural Network (ANN)-based control scheme for fast electric vehicle (EV) charging applications. The system is further enhanced by incorporating an isolated bidirectional Dual Active Bridge (DAB) DC-DC converter, also governed by ANN control. The proposed architecture achieves superior performance by minimizing the variable DC-link voltage, enabling high-frequency soft switching, and employing an integrated magnetic-linked converter design. These results in a compact and highly efficient system compared to conventional PI-controlled converters. The totem-pole configuration, replacing traditional full-bridge diode rectifiers with active switches, significantly improves power factor correction (PFC), reduces total harmonic distortion (THD), and enhances overall power quality. Constructed using high-frequency gallium nitride (GaN) switches, the converter allows for precise voltage and current regulation with reduced switching losses. Simulation results performed in MATLAB demonstrate the effectiveness of the ANN-controlled bidirectional converter in terms of improved dynamic response, reduced THD, and increased system efficiency, making it suitable for advanced EV charging infrastructures and uninterruptible power supply (UPS) applications.

In this paper, a bidirectional capacitor-inductor-inductor-inductor-capacitor (CLLLC) resonant converter based on a wide bandgap (WBG) transistor is designed and analyzed at MHz-level switching frequency to accomplish high power density and high efficiency. A discrete-time Proportional-Integral-Derivative (PID) controller based on phase shifted pulse width modulation (PWM) technique has been developed for the closed-loop control of the aforementioned CLLLC converter. The converter is designed with WBG switching devices to accomplish fast switching with minimal switching losses, and it is also compared to Si-based switching devices. For the proper thermal design of the converter, a precise power loss model of the switching devices has been developed. A 5 kW CLLLC converter with 400-450V DC input and 250-465V DC output with an operating frequency of 1 MHz has been designed and simulated under a variety of loading conditions. The maximum conversion efficiency achieved with Gallium Nitride (GaN)-based devices was 97.2 percent in forward mode and 97 percent in reverse mode.

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In this paper, a Series Resonant Converter (SRC) is evaluated for on board charging applications of electric vehicles (EVs) with relatively wide output voltage range requirement. Due to strict real estate and weight budget of EVs it is imperative to enable power dense battery charging converters. One approach towards increasing power density of such DC-DC converters is to increase the switching frequency to several hundred kilohertz enabled by the use of wide band gap semiconductors such as Gallium Nitride (GaN) based switches. Furthermore, to accommodate the battery voltage variation with state-of-charge of the cells, wide gain range operation from a narrow range bus voltage (produced by power factor correcting front end) is required. Bidirectional operation of the converter is also essential to sustain vehicle to grid or vehicle to load (V2X) functionalities. Series resonant converters, utilizing delay time control, can be a suitable candidate for high frequency, high power density, wide gain range, bidirectional operation due to it's capability of maintaining soft switching across wide gain range with reduced frequency variation. To evaluate it's potential in high frequency applications, in this work, a series resonant converter with 650 V GaN devices is constructed, operating from a DC input voltage of 800 V, to be compatible with PFC stages operated from both single and three phase AC inputs. This prototype converter switches at a nominal frequency of 500 kHz and delivers a rated power of 6.6 kW, achieving 7.3 kW/L power density. Low profile of the converter is achieved by the use of planar cores with Litz wire windings. The converter's performance is experimentally verified over an output battery voltage range of 200 - 350 V, where it achieves greater than 97% efficiency with a peak value of 98.5%.

This paper proposes a Gallium Nitride high-electron mobility transistor (GaN HEMT) based three-port DC-DC converter for Level-1 and Level-2 electric vehicle charging. The three-port converter (TPC) is based on an isolated bidirectional Dual Active Bridge (IBDC-DAB) configuration for battery charging applications. The proposed DAB based TPC uses fewer components as compared to separate charger systems. The phase-shift control method is implemented to control the output power of the IBDC-DAB based converter with two charging output ports. The highest efficiency of 98.86% is achieved with the proposed converter at a phase-shift of 0.3889. The output ports 2 and 3 are designed for Level-1 and Level-2 EVB charging. Maximum power of approximately 2 kW for Level-1 and 12 kW for Level-2 is achieved for output Port 2 and 3 at an overall efficiency of 97%. The performance metrics of the IBDCDAB-based TPC have been analyzed and simulation is performed using LTspice XVII software. The results are presented for validation.

The rapid growth of global electric vehicle (EV) adoption, fueled by advancements in power electronics and battery technologies, has led to an increasing demand for fast and efficient charging solutions. There is a rising research interest in compact EV supply Equipment(EVSE) with vehicle-to-grid (V2G), vehicle-to-home (V2H), and vehicle-to-load (V2L) capabilities, as these systems play a crucial role in improving grid resilience and energy flexibility.A need of high performance with improved power density has drifted the designs from Silicon (Si) to Gallium Nitride(GaN). This paper presents the design and implementation of a high-frequency bidirectional EV charger utilizing Gallium Nitride (GaN) power devices for improved efficiency and compactness. The system operates at 200 kHz and consists of two power conversion stages: a totem-pole power factor correction (PFC) converter, which rectifies the singlephase 230 V AC input to 400 V DC while achieving high power factor, and a dual active bridge (DAB) converter, which provides galvanic isolation and efficient DC-DC conversion to 48 V DC. A novel control strategy is introduced to address zero-crossing challenges in the totem-pole PFC, ensuring stable operation and minimal harmonic distortion. The use of GaN devices enables high-frequency operation, reducing passive component value, size and enhancing power density. Experimental results validate the effectiveness of the proposed design, demonstrating high efficiency, stable operation, and reliable bidirectional power transfer. This work contributes to the development of compact, high-performance EV interfaced (V2H) systems that support grid stability and energy resilience in residential applications.

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The wide band gap devices Gallium Nitride (GaN) and Silicon Carbide (SiC) solutions are becoming more popular in high-voltage power electronic applications. Also, they provide lower switching losses and the ability to increase switching frequencies. On the other hand, magnet less induction motor (IM) drive offers superior performance compared to other electrical machines. This paper proposed a hybrid combination of IM and bidirectional DC-DC power converters in Electric Vehicles (EVs) that helps to improve the overall performance. Therefore, improving IM and DC-DC converter topologies is essential in the future development of EV infrastructure. The integrated module reduces the cost, volume, weight, and compact size to increase the performance and consistency of the vehicle. As a solution, an IM-based DC-DC dual active bridge bidirectional converter analyzes the dynamic behavior of the machine. The implementation of this work is executed using MATLAB software. The simulation results show that the suggested design of the IM and power converter module has greater efficiency.