High-frequency design considerations of dual active bridge 1200 V SiC MOSFET DC-DC converter

Abstract

Silicon carbide (SiC) is more favorable than Silicon (Si) to build high voltage devices due its wider band-gap and higher critical field strength. Especially, the SiC MOSFETs are finding their niche in 1 kV range, which is currently dominated by Si IGBTs. This paper aims at demonstrating high power and high frequency operation of the SiC MOSFETs, as a means to evaluate the feasibility of using SiC MOSFETs for high power density applications. The sample devices chosen for this study are 1200 V, 20 A, SiC MOSFETs co-packed with 10 A JBS diodes - manufactured by the CREE Inc. A dual active bridge (DAB) converter has been built to validate the suitability of SiC devices for high power density converters. The design details of the DAB hardware, and the high frequency transformer used for interfacing both the bridges are given. Experimental results on the DAB at 100 kHz switching frequency are presented. Finally, the device switching waveforms up to 1 MHz are given.