The fuzzy droop control design for storage system of DC microgrid

DC microgrid is widely used in data centers and remote area power supply. The energy storage system is very important in improving system stability and voltage quality of the microgrid through buffering the intermittence of distributed generations. In order to balance the state of charge (SOC) among different storage units and to avoid the over charge or deep discharge of the units with higher/lower SOC, the piecewise fuzzy droop control is proposed for the energy storage system in the paper, which is based on the coordination control of multi-source DC microgrid. Specifically, the proposed method modifies the virtual impedance of the droop controller in the storage units through considering the SOC difference of each storage unit, and realizes dynamical power allocation timely. The DC microgrid simulation model is built in Matlab/Simulink and the parameters are selected to compare the control effects of different fuzzy segmentations, which verify the effectiveness and feasibility of the proposed method.