This paper proposes a co-design optimization procedure of a high-power off-board charger for electric vehicle (EV) applications. The primary purpose is to design a 175 kW SiC DC-charging system with high power density to achieve high efficiency at a wide operating range. For the active part of the DC off-board charger, a three-phase active front end (AFE) rectifier topology is considered in the design optimization and the modelling. The design methodology focuses on the optimal design of the passive filters, accurate electro-thermal modelling of the converter, inductor design, capacitor selection, loss and geometric modelling of the passive filters and control system design. The design optimization of the high-power charging system is performed in MATLAB Simulink using a closed-loop dynamic electro-thermal simulation of the off-board charger. The switching frequency, loss and temperature-dependent efficiency of the charger is investigated in parallel. Through this proposed technique, efficiency greater than 96% is achieved at a switching frequency of 40 kHz, along with a smaller size and lower weight of the system. Moreover, it operates with a current total harmonic distortion (THDi) below 3% and a power factor (PF) above 99% at rated power condition.

The wide-scale adoption and accelerated growth of electric vehicle (EV) use and increasing demand for faster charging necessitate the research and development of power electronic converters to achieve high-power, compact, and reliable EV charging solutions. Although the fast charging concept is often associated with off-board DC chargers, the importance of on-board AC fast charging is undeniable with the increasing battery capacities. This article comprehensively reviews gallium nitride (GaN) semiconductor-based bidirectional on-board charger (OBC) topologies used in both 400 V and 800 V EV applications. Moreover, comparative evaluations of GaN-based bi-directional OBC topologies regarding power conversion losses (conduction loss and soft switching capabilities), power density, implementation considerations, power quality, electromagnetic interference, and reliability aspects have been presented. The status of commercially available GaN power modules, advancements in GaN technology, applicable industry standards, and application requirements for OBCs have been also included in this study. Finally, in light of forthcoming advancements in GaN power transistor technology, this study highlights potential areas of research related to the reviewed topologies. Such research can aid researchers and designers in improving the performance and user experience of electric vehicles, ultimately supporting the widespread adoption of EVs.

Along with the technology boom regarding electric vehicles such as lithium-ion batteries, electric motors, and plug-in charging systems, inductive power transfer (IPT) systems have gained more attention from academia and industry in recent years. This article presents a review of the state-of-the-art development of IPT systems, with a focus on low-voltage and high-current electric mobility applications. The fundamental theory, compensation topologies, magnetic coupling structures, power electronic architectures, and control methods are discussed and further considered in terms of several aspects, including efficiency, coil misalignments, and output regulation capability. A 3D finite element software (Ansys Maxwell) is used to validate the magnetic coupler performance. In addition, a 2.5 kW 400/48 V IPT system is proposed to address the challenges of low-voltage and high-current wireless charging systems. In this design, an asymmetrical double-sided LCC compensation topology and a passive current balancing method are proposed to provide excellent current sharing capability in the dual-receiver structures under both resonant component mismatch and misalignment conditions. Finally, the performance of the proposed method is verified by MATLAB/PSIM simulation results.

Gallium nitride (GaN) power semiconductors are being explored as promising alternatives for the next generation of high-power traction inverters, suitable for both high- and low-voltage applications. In such scenarios, the peak current can reach several hundred amps. Hence, using multiple GaN HEMT chips or dies in parallel is definitely a design approach to extend power capacity and minimize power losses. However, the parallelization and packaging structure of GaN devices present numerous challenges. Achieving balanced dynamic and static current sharing between paralleled devices, as well as ensuring robust gate driving signals, is indispensable for reliable operation during high dV/dt and di/dt transients, particularly with switching noise-sensitive gate-source threshold voltages. Additionally, thermal dissipation and mechanical stress must fulfill industrial requirements. This paper introduces a compact 100 V/360 A GaN power module specifically designed for packaging on insulated metal substrates (IMS) or direct-bonded copper (DBC). The proposed packaging approach offers superior electrical performance, excellent thermal dissipation, minimal mechanical stress, and a cost-effective solution. Finally, the advantages of the proposed power module design are validated through various experimental setups, including a 48 V/328 A double pulse test, a 48 V/24 V 3 kW buck converter implementation, and a 48 V/5 kW three-phase inverter demonstration.

Radio Frequency Wireless Power Transfer (RFWPT) systems operating at higher frequencies such as 6.78 MHz are drawing a lot of attention due to their advantages such as the improved user convenience, the compact size and the light weight. In a WPT charging system the DC/DC converter, which provides an accurate voltage and current to the battery is essential for its safety and lifespan. This paper presents the design and implementation of a high efficiency, light weight-Megahertz WPT system that makes it possible to charge Lithium Batteries by Constant Current (CC) and Constant Voltage (CV) charging with a pair of coils. The proposed WPT charger is simple in structure since it does not require a feedback circuit to implement CC/CV charging. Hence, no communication between the primary side and secondary side is needed. Since the charger can provide automatic mode transfer from CC to CV charging, the battery can be fully charged without the help of an additional DC/DC converter. Simulation and experimental results obtained with a 50W WPT charger operating at 6.78-MHz are presented to verify the feasibility and the validity of the proposed method.

This paper presents the design investigation of liquid cooled heat sinks for a 48V/35 kW GaN FET dual three-phase inverter using CFD analysis. With the use of GaN FETs, higher power density can be realized in power electronics components which results in higher heat density as well. In order to find an optimal heat sink configuration, the cooling performance of two different configurations of cold plates is investigated and compared with commercially available cold plate. And the distribution characteristics of the temperature, pressure and fluid velocity field are compared and analyzed.