Zero-Voltage Switching Control of a Grid-Connected Interleaved Inverter with Variable Switching Frequency

Interleaved technique is widely applied in ac-dc, dc-dc, and dc-ac converters to improve the dynamic response, efficiency and power density. While a multi-phase interleaved converter reduces the total output current ripple, each interleaved phase can operate in the high current ripple (HCR) mode to minimize the inductance. This paper proposed a variable switching frequency control in a grid-connected interleaved inverter to keep a stable valley current with the opposite polarity to the average current, so to achieve the ZVS mode. The proposed approach realizes the ZVS operation at full ranges of a grid-connected application, and can be easily implemented in a digital signal controller. In addition, the effectiveness of the ripple cancellation is investigated at variable switching frequency. The effectiveness and performance of the proposed control methods is validated by experiments.