Zero-Voltage-Switching Sinusoidal Pulsewidth Modulation Method for Three-Phase Four-Wire Inverter

A zero-voltage-switching (ZVS) sinusoidal pulsewidth modulation (SPWM) method for a three-phase four-wire inverter is proposed in order to achieve higher efficiency and power density. With the proposed modulation scheme, the ZVS operation of all switches, including the main switches and the auxiliary switch, can be realized. Besides, all seven switches operate at a fixed frequency. The ZVS SPWM scheme is introduced by considering the various combinations of the polarities in three-phase filter inductor currents and the analysis of operating stages is presented. ZVS condition of the ZVS SPWM scheme is derived and discussions of ZVS condition for typical three-phase loads are also provided. In addition, the resonant parameters design and loss analysis are briefly investigated. Finally, the proposed ZVS SPWM scheme is verified on a 10-kW inverter prototype with SiC mosfet devices.