一种具有扩展软开关范围的新型双半桥单级单相逆变器

Compared with the other single-stage single-phase inverter topologies, the dual-active-bridge (DAB)-based inverter offers fewer switches and easier implementation of soft switching. With the extended phase-shift (EPS) plus variable- strategy, all the converter switches can achieve zero-voltage soft switching (ZVS) under heavy load conditions, but while the load decreases, the lagging switches on dc side will lose the ZVS operation. This article proposes a novel dual-half-active-bridge-based single-stage inverter. While the traditional full-bridge topology is substituted by a dual half one, the soft-switching range for those lagging switches can be effectively extended. All the switches in the proposed inverter can achieve ZVS across the entire line frequency cycle under wide load ranges. The theoretical analysis of the proposed converter is presented, and the experimental demonstration with a 48-Vdc /220-Vac /500-W inverter prototype verified the effectiveness of the proposed inverter and the correctness of the analysis and design.