A Fully ZVS Dual-Active-Bridge Based Three-Port Converter with High Integration

A novel dual-active-bridge based three-port converter (TPC) is proposed for islanded dc microgrids. The proposed converter can interface among three ports (PV source, battery, and dc-link) simultaneously with high integration. Rechargeable battery operates as an energy buffer to compensate for power mismatch between PV source and dc-link. Electric power can flow bi-directionally between the battery and dc-link. Pulse-width-modulation (PWM) on the primary side is utilized to realize the maximum power point tracking (MPPT) of PV panel. An optimized phase-shift-modulation (PSM) is introduced to regulate power flow, ensure ZVS among all MOSFETs and reduce circulating current over a wide range. To verify this concept, a 500 W rated prototype is designed. The designed prototype exhibits high efficiency in various operating modes. The experimental results agree well with the theoretical analysis.