Modeling and Optimization for DAB Converter using SiC MOSFETs in Series Connection Considering Magnetizing Inductance and Voltage Ratio

In the field of medium voltage power transmission, the DAB converter using series-connected SiC MOSFETs (S-SiC) is a preferred solution for isolated bidirectional DC-DC conversion. However, S-SiC cannot achieve zero voltage switching-on (ZVS-on) under some operating conditions, which compromises the efficiency and reliability of the converter. This paper proposes an optimization scheme for a DAB converter with S-SiC by focusing on the magnetizing inductance and voltage ratio. The operational modes of the converter under various conditions are analyzed, and key characteristics are identified to guide the optimization design. Finally, experiments on the developed 4kV/200kW prototype demonstrate enhanced ZVS-on scope and voltage sharing in the S-SiC.