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.