SoC Balancing Strategy Accounting for Transient Current Equalization under Sudden System State Changes Based on Adaptive Droop Control

DC microgrid is often equipped with energy storage (ES) to eliminate the random output of renewable energy sources and load fluctuation. Due to the difference in line impedance among ES, the sudden change in common load impedance(CLI) or the connection of converter local load (CLL) will affect the transient current equalization accuracy of ESs, leading to the deterioration in the SoC balancing. In this paper, the SoC and output current of ES are both associated with the droop coefficient, whose weights are adaptively allocated according to the operating state of the system. preventing the deterioration of the transient current equalization accuracy due to the sudden change of the system state. Secondary regulation is further adopted to eliminate voltage deviation caused by droop control. Finally, the overall control strategy is analyzed in terms of stability to ensure its feasibility. The correctness and effectiveness of the proposed strategy are verified by Matlab/Simulink simulation comparison.