Improved Adaptive Droop Control of Distributed Energy Storage SOC

As an important part of DC microgrid, distributed energy storage system mainly consists of multiple energy storage units. In DC microgrid, droop control is mostly used for micro sources, which can realize reasonable power distribution among micro sources. However, traditional droop control based on state of charge(SOC) suffers from the problems of slow balance and power overload. An improved adaptive sagging control strategy for distributed energy storage SOC is proposed to solve the above problems. Firstly, the traditional sagging control is analyzed and the model affecting SOC change rate of energy storage unit is derived. Secondly, an improved adaptive droop control strategy for distributed energy storage SOC is proposed, and a growth coefficient is introduced based on the traditional SOC droop control. Thirdly, the output power ratio between energy storage units is analyzed and the growth coefficient parameters are designed to realize SOC fast balancing on the basis of limiting the output power of energy storage units. Finally, the effectiveness of the proposed control strategy is verified by Matlab/Simulink model.