A novel DC-rail parallel resonant ZVT VSI for three-phase AC motor drive

This paper proposes a novel circuit of DC-rail parallel resonant zero voltage transition voltage-source inverter (DC-Rail PR ZVT VSI) for three-phase motor drive. In this circuit all switches are turned on or turned off under the zero voltage switching (ZVS) or zero current switching (ZCS) without high stress of voltage and current. Power ratings of the resonant components and auxiliary switches required are small. The control scheme is simple and less dependant on load current This paper gives details of the theoretical analysis, the rules of selecting the auxiliary switches and the commutation components and the control strategy of the proposed circuits. Finally, the validity and the efficiency of the circuit are tested and verified by experiment results. Some questions in practical application are discussed.