Quasi-resonant soft-switching inverter for low and high power factor loads

A novel quasi-resonant three-phase inverter is proposed for 400 or 50 Hz low and high power factor loads. The proposed quasi-resonant DC link consists of a total of four switches, two resonant inductors and a capacitor. Two switches are connected in series with the resonant DC link (RDCL) and the other two are connected across the RDCL. The quasi-resonant link topology is versatile and the operation is such that the DC link voltage is clamped to the source voltage. The soft-switching operation of the quasi-resonant inverter is explained in terms of modes for both positive and negative link current. The quasi-resonant inverter is operated under modified space vector modulation incorporating soft switching. SABER simulation of the resonant link inverter and subsequent experimental verification show good agreement.