6.78 MHz 2.8 kW Resonant DC-DC Power Conversion Utilizing 650 V GaN HEMT-Based H-Bridge Inverter

This paper aims to investigate the challenges and feasibility of using 650V gallium nitride (GaN) high-electron-mobility transistors (HEMT) for multi-kilowatt (kW) power conversion at 6.78MHz. A transformer-based isolated resonant DC-DC converter operating at 6.78MHz is developed and driven by a GaN H-bridge inverter. The design challenges associated with high-power GaN H-bridge inverters at this frequency are thoroughly analyzed and summarized. Two inverter prototypes are implemented using GS66508T and GS-065-030-2-L HEMTs, with detailed design considerations provided. Experimental results demonstrate that the resonant DC-DC power conversion system achieves 2.8kW at 400V with a peak efficiency of 95.60% using GS66508T, and 2.06kW at 350V with a peak efficiency of 94.74% using GS-065-030-2-L.