Zero-Voltage-Switching SiC-MOSFET Three-Phase Four-Wire Back-to-Back Converter

This paper proposes a novel zero-voltage-switching (ZVS) three-phase four-wire back-to-back (BTB) converter topology and its ZVS sinusoidal pulsewidth modulation (ZVS-SPWM) scheme. With the proposed ZVS-SPWM scheme, all the main switches in both the rectifier side and inverter side and the auxiliary switch can realize ZVS turn on with only one auxiliary circuit. In addition, the auxiliary switch only needs to operate once in each switching period, which can cut down an extra loss of the auxiliary circuit. The operation stage analysis is introduced, and the ZVS condition for the switches is derived. The ZVS BTB converter is investigated with respect to both balanced and unbalanced load conditions. In additon, the soft-switching parameter design guideline is discussed. Finally, the proposed ZVS BTB converter and its ZVS-SPWM scheme are verified on a 9-kW prototype with the SiC-MOSFET device.