A Bus Voltage Regulation Strategy without Communication for Improving Efficiency of Photovoltaic Series-Connected Power Optimizer System

A new DC bus voltage regulation and coordination control strategy of the photovoltaic series-connected power optimizer system without communication is proposed in this paper, which considerably improves the efficiency of the overall system without any cost increase. Photovoltaic series-connected power optimizer system includes pre-stage optimizers and a post-stage energy converter. The pre-stage optimizer achieves maximum power point tracking by controlling the output voltage of the photovoltaic module, which solves the problem of energy loss caused by PV cells mismatch, component aging and shadow occlusion. The post-stage converter is used to balance the energy between the DC bus and the post-stage system.