A bidirectional single‐phase Z‐source AC‐AC converter with reduced voltage stress on switches and safe commutation strategy

Abstract

SummaryIn this paper, a bidirectional single‐phase Z‐source ac‐ac converter is proposed. Common features between the proposed converter and its counterparts are the capability of boost in‐phase, buck out‐of‐phase, and common ground. The output voltage gain of the proposed converter is improved compared with previous Z‐source ac‐ac converters, while the total standing voltage (TSV) of the switches has also been significantly reduced. Owing to the reduction of voltage stress of semiconductor elements, the switching device power (SDP) of the proposed converter is reduced. As a result, the cost of the converter is also reduced. A bidirectional switch is replaced instead of the output filter inductor to reduce the volume and weight of the converter. A safe commutation strategy is applied to eliminate voltage spikes on switches. Furthermore, the proposed converter can transfer power in both directions. By evaluating the converter in different operating modes, the key relationships and parametric design of the converter are presented. A laboratory prototype is made to confirm the proposed converter performance.