Research on Self-compensating Dynamic Droop Control Strategy of Microgrid Energy Storage System

In order to take advantage of the energy storage system in maintaining the microgrid system power balance, an improved state of charge (SOC) based dynamic droop control strategy with self-compensation for energy storage systems is proposed in this paper. The traditional large droop coefficient leads to bus voltage deviation, and the fixed droop coefficient to control charge and discharge of energy storage system would cause overcharge and over-discharge of battery. Therefore, a new dynamic droop coefficient is designed to distribute the power proportional of the SOC value of the storage system. In addition, the voltage compensation algorithm is deduced to eliminate the bus voltage deviation caused by droop control. Compared to the conventional secondary control, the proposed method reduces the control complexity. Finally, the proposed control structure is verified by Matlab/Simulink simulation.