Design, Implementation, and Comparison of Multi-MHz Multi-kW H-Bridge Inverters Based on 650V SiC and GaN Devices for High-Frequency WPT

Aiming at high-frequency and high-power wireless power transfer (WPT), this paper identifies the challenges that limit an H-bridge inverter working at multi-megahertz (MHz) multi-kilowatt (kW) scenarios, including the overheating issue of multi-MHz operated gate driver, thermal dissipation incapability of switching device at multi-kW, and difficulty in achieving zero-voltage-switching. The methodology to enhance the high-frequency switching capability is demonstrated in switching device selection, soft-switching realization, and parasitic inductance minimization. Three H-bridge inverters are respectively designed and implemented using 650V silicon carbide (SiC) MOSFET C3M0060065K and 650V gallium nitride (GaN) FETs TP65H070G4PS and GS66506T. High-frequency switching tests reveal the overheating of the SiC gate driver, achieving 180°C at 4MHz, much higher than GaN drivers. High-power tests at 4MHz with DC voltage ranging from 75V to 500V revealed that SiC C3M0060065K and GaN TP65H070G4PS inverters have good high-power conversion capability, achieving 3.8kW at 500V. In contrast, the GaN GS66506T inverter shows thermal dissipation incapability with a maximum power of 2.28kW at 375V. With a wide power range, the maximum efficiency of three inverters respectively achieves 97.22% (GaN GS66506T), 97.1% (GaN TP65H070G4PS), and 95.22% (SiC C3M0060065K). © 2024 IEEE.