Design and Implementation of Full-Bridge Resonant Converter with GaN E-HEMT

Increasing the switching frequency of the power converters can increase the power density, but it will cause more switching losses. Gallium nitride enhancement mode high electron mobility transistors (GaN E-HEMTs) have fast switching speed characteristic, it is suitable for high switching frequency applications. In this paper, GaN E-HEMTs are used as the main switches of the full-bridge resonant converter with soft-switching to increase the power density with high frequency operation. The characteristics of GaN E-HEMT are investigated, the operating principles of full-bridge resonant converter are analyzed, and the design considerations of gate drive circuits are discussed in this paper. The digital signal processor, TMS320F28335, is used as the main controller. Finally, an experimental prototype is built with the switching frequency of 1 MHz, the input voltage of 380-420 V, the output voltage of 48 V, and the rated power of 960 W The highest efficiency is 90.5 % at 50 % load.