IEEE Workshop on Wide Bandgap Power Devices and Applications in Asia (WIPDA-ASIA 2021)

In order to realize a silicon carbide (SiC) MOSFET soft-switching inverter with high efficiency, low voltage stress and convenient control, a novel parallel resonant DC link soft-switching inverter is proposed in this paper. It can realize zero-voltage turn-on/off of main switch in the inverter bridge and zero-voltage/current turn-on/off of auxiliary switch in the auxiliary circuit, and it is convenient to control without setting inductor current threshold. At the same time, it avoids using coupled inductor and split capacitor which reduce power density, and the latter will also bring neutral point potential drift. The control of soft-switching inverter is simple and independent of load conditions, and the required time of transition process can be freely selected. In this paper, under the proposed modulation strategy, according to the equivalent circuit in the different work modes, the operation principle, soft-switching realization conditions and parameter design methods of the inverter are analyzed. At last, a 5kW prototype is made by using SiC MOSFET as switching device, and the effectiveness of the inverter is verified by experiments.

SiC MOSFET,soft-switching,zero-current,zero-voltage,parallel resonant DC link inverter