A Zero-Voltage Switching Three-Phase Inverter

A new modulation scheme for the active clamping zero-voltage switching (ZVS) inverter is proposed. With the proposed modulation scheme, the inverter can realize ZVS operation in all switching devices and can remarkably suppress the reverse recovery current in insulated-gate bipolar transistor's antiparallel diodes as well. All the switches can operate at a fixed frequency in the new modulation scheme. Also, with the new modulation scheme, the ZVS inverter has some voltage boost capability, which is suitable for renewable energy generation. The inverter can achieve ZVS in all the switches under the grid current power factor angle from zero to +/-pi/6. The soft-switching condition of this inverter is analyzed. The operation principal and design guideline are described in detail. The previous theory is verified in a 30-kW inverter prototype.