On 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 VSIpsila) 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. The control scheme is simple and less dependent on load current. This paper gives the theoretical analysis of efficiency and the unbalancing problem of neutral-point voltage with light load. A detailed design procedure of the rules of selecting the auxiliary switches, the commutation components and the control strategy of the proposed circuits is also presented in this paper. Finally, the validity of the circuit are tested and verified by experiment results.