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 plus variable frequency modulation 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 paper 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 entire line frequency cycle under wide load ranges. The theoretical analysis of the proposed converter is presented and the experimental demonstration with a 48Vdc/220Vac/500W inverter prototype verified the effectiveness of the proposed inverter and the correctness of the analysis and design.