Optimal control of energy storage system of high-permeability distributed photovoltaic low-voltage distribution network

Photovoltaic (PV) is one of the very promising renewable energy sources, but its output power is fluctuating. To maintain PV-energy storage system-load power balance in low-voltage distribution networks, we propose a new optimized sag control strategy, which is no longer indexed by the battery voltage but by the battery state of charge (SOC) because the battery SOC can better reflect the remaining battery capacity for better performance. In addition, to further optimize its performance, we try to use the ratio of intercell SOC for optimization. We analysed the deficiencies of sag control in detail, derived a control strategy with cell SOC as an indicator and finally analysed its performance in detail. To verify the performance of the proposed strategy, based on MATLAB, we designed the power variation of 2 lithium-ion battery packs to maintain the bus power stability under two cases of sudden rise as well as sudden fall of PV power and 3 lithium-ion battery packs to maintain during the bus power stabilization with one set of performance after failure, and the simulation results prove the feasibility of the proposed strategy.