Design Optimization and Performance Evaluation of High-Power, High-Frequency, Bidirectional Buck-Boost Converter with SiC MOSFETs

This paper presents the design optimization and experimental results for a 150-kHz, high-power, non-isolated, bidirectional buck-boost converter operated in continuous-conduction mode (CCM) and implemented with SiC MOSFETs. Although the SiC MOSFETs exhibit a much better reverse-recovery characteristic than their Si counterparts, their efficiency at high- frequencies can be significantly improved by implementing soft switching, i.e., by turning them on at zero voltage. In this paper, soft-switching of the bidirectional buck-boost converter is implemented by employing an active snubber that achieves zero-voltage switching (ZVS) of the main switches and zero-current switching (ZCS) of the snubber switches. The measured peak efficiency of the experimental 10-kW soft-switched prototype designed for 160-250 V input range and 330-V output is over 98.5% for both boost and buck modes of operation.