Virtual SVPWM Based Flexible Power Control for Dual-DC-Port DC-AC Converters in PV-Battery Hybrid Systems

A dual-dc-port dc-ac converter with virtual space vector pulse-width modulation (SVPWM) based flexible power control is proposed for photovoltaic (PV)-battery hybrid systems. Two dc ports, in which one dc port is interfaced with PV and the other dc port is interfaced with the battery, are provided simultaneously by the dual-dc-port dc-ac converter. Hence, all the active power is transferred within single power conversion stage, and the dc-dc converter between PV and battery is removed. To realize flexible power control between PV, battery, and ac grid, a new control scheme consisting of an outer power loop and an inner virtual SVPWM is proposed, with fully considering the voltage variation of both PV and battery. Operation principle and power control capability of the dual-dc-port dc-ac converter are analyzed in detail. The effectiveness of the proposed solution is validated by experimental results.