Variable Switching Periods Based Space Vector Phase-Shifted Modulation for DAB Based Three-Phase Single-Stage Isolated AC–DC Converter

The maximum phase current (the maximum transfer power) of the dual-active-bridge based three-phase single-stage (DAB-3P1S) ac–dc converter with the present dual-period-decoupled space vector phase-shifted modulation (DPD-SVPSM) is analyzed for the first time in this article. It shows the equal switching period assignment way of the present DPD-SVPSM reduces the utilization of the control period, thus limiting the maximum transfer power of DAB-3P1S ac–dc converter. To enhance the maximum transfer power, a variable switching period based dual-period-decoupled space vector phase-shifted modulation (VDPD-SVPSM) is proposed. Besides, the current stress of DPD-SVPSM and VDPD-SVPSM are analyzed and compared. And it indicates that by properly designing the transformer leakage inductor, VDPD-SVPSM improves the maximum phase current (maximum transfer power) without increasing the current stress of the device, thereby improving the utilization of the system hardware rated capacity then increasing the power density. Detailed experimental results validate the correctness of the theoretical analysis and the feasibility of the proposed VDPD-SVPSM.