Dual-Path Series-Resonant Single-Stage DC–AC Converter Operating in Hybrid Mode

This article proposes a dual-path series-resonant single-stage dc–ac converter operating in hybrid mode. The proposed circuit provides dual power transfer paths regardless of the switching state; secondary diodes of the proposed converter are integrated into one of the two complementary pairs of the secondary-side switches, thereby contributing to the reduced circuit complexity and cost. The proposed dc–ac converter operates in below resonance mode (BRM) above the computed instantaneous power level and in above resonance mode (ARM) below this level. During BRM, it can achieve a step-up function with high power conversion efficiency. Since BRM is devoid of step-down capability, ARM is developed and used in the region where the step-down operation is required. We also identify the boundary of operation modes in the hybrid-mode single-stage dc–ac converter and provide guidelines to design the circuit parameters. Finally, we implemented a 300-W prototype to validate the analysis and benefits of the proposed converter.