Direct Power Distribution Strategy Based on Space Vector Modulation for Single-Stage Dual-DC-Port Inverter

The single-stage dual-dc-port inverter directly connects the photovoltaic-battery hybrid system to the ac side, which offers the advantages of high efficiency and low cost due to the removal of dc–dc converter. The existing modulation-based power distribution strategies realize flexible power flow control by indirectly regulating redundant zero or small vectors via additional outer loop power controllers, which have the drawbacks of limited steady-state and dynamic response. To address this issue, the relationship between the dc-port power and large/small vectors is analytically revealed, which provides intuitive parameter design guidelines for power distribution control. On this basis, a direct power distribution strategy based on space-vector modulation is proposed, which regulates the dc-port power by splitting the reference voltage vector into large and small vectors. Compared to the conventional strategies, the proposed strategy shows better steady-state and dynamic response due to desirable power control directly realized in the modulation layer. Finally, the comprehensive comparison experimental tests are conducted to verify the effectiveness and advantages of the proposed direct power distribution strategy.