Analysis and design of snubber circuit for Z-source inverter

The Z-Source Inverter (ZSI) is a novel and attractive topology for an power electronic interface. Shoot-through states are utilized to boost the DC bus voltage, which also differentiates the working process of the snubber circuit from that of a Voltage Source Inverter (VSI). It was found that there would be a distortion in the DC link voltage of four traditional snubber circuits, and that this voltage would increase more than it would have without the snubber circuit. Compared with a VSI, larger energy losses would be generated in this situation due to the shoot-through state. This paper presents an improved RCD snubber circuit for ZSI applications, which resolves the problems of voltage distortion and large energy losses. These theoretical findings and design guidelines for snubber circuits with a ZSI were then verified by computer simulation and experiment.