Modulation schemes with enhanced switch thermal distribution for single-phase AC-DC-AC reduced-switch converters

Modulation schemes can significantly change the performance of a power converter in steady state, and they have been extensively studied, but mostly directed to three-phase topologies, where triplen offsets are added. Single-phase systems, including ac-dc-ac systems, are less widely pursued, even though various topologies have been proposed. The motivation of this paper is to study two promising single-phase ac-dc-ac converters using reduced number of switches, and subsequently proposes new modulation schemes for them. The proposed schemes help the converters to achieve a better thermal spread among their switches, while keeping their dc-link voltages low. Single points of failure are thus minimized, allowing the converters to have longer lifetimes. Simulation and experimental results have demonstrated the intended performances and hence verifying the idea.