Performance improvement strategy for photovoltaic generation through dynamic reconfiguration of cell strings

In this paper, a strategy for the dynamic reconfiguration of photovoltaic (PV) strings and inverters is proposed to improve the PV system efficiency and reduce the harmonic emissions of the PV system under low irradiance conditions. In the proposed PV group control system, parallel-bridge switches are controlled to form multi-PV groups that can run jointly with multi-inverters. The benefit and harmonic current of the group control system are used to define the performance index. The dynamic reconfiguration strategy is used to control the connection mode of the PV system to optimize the index. The fluctuation of the PV string output power on the time scale is considered, the PV power variation range is predicted based on the least squares regression algorithm, the connection modes of the PV system are evaluated to prevent inverter overload, and the optimal connection mode is decided when the system frequently switches based on the voting theory method. An experimental system platform comprising three PV array simulators and three inverters is designed, and several scenarios of PV system operation are constructed to verify the feasibility and effectiveness of the proposed strategy. Experimental results show that compared with the conventional PV operation mode, the proposed strategy can improve PV generation performance under low solar irradiation. Based on the benefits of the control strategy, the scheme cost and recovery time are evaluated, and investors can quickly recover costs.