Efficiency Improvement Control Strategy for Photovoltaic Generation Through DC Dynamic Reconfiguration
Xue Shiwei1, Jia Qingquan1, Li Pan1, Liang Jifeng2, Geng Liang3
1. Key Lab of Power Electronics for Energy Conservation and Motor Drive of Hebei Province Yanshan University Qinhuangdao 066004 China; 2. Electric Power Research Institute of State Grid Hebei Electric Power Supply Co. Ltd Shijiazhuang 050021 China; 3. Shijiazhuang Power Supply Branch of State Grid Hebei Electric Power Co. Ltd Shijiazhuang 050021 China
Abstract：In order to solve the problem of low efficiency of string inverter during uniform and low irradiance conditions, a DC side switch reconfiguration strategy is proposed to improve the parallel efficiency of the string inverter. Based on a photovoltaic(PV) DC switch topology, switches are controlled to form multi-PV groups that can run jointly with multi-inverters. The efficiency of PV system and the electrical life of switches are considered. The number of inverters is controlled to optimize the benefit index function of the PV system. Based on the least-squares regression algorithm, short time range of weather is predicted. The connection methods of the PV system structure are analyzed to prevent power violation of inverters. The best switch connection at different times is compared to determine the best connection scheme. The times of switching is minimized by the scheme. Finally, the final scheme of DC switch reconfiguration is decided by control decision. The proposed strategy is compared with PV generation strategies of consider only objective function and conventional to verify the effectiveness and feasibility of this strategy.
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2021, Vol. 36 
