Power Distribution Control of Hybrid Energy Storage DC Microgrid Based on Fuzzy Variable Time Constant

In order to give full play to the advantages of high energy density of battery and high power density of supercapacitor, a fuzzy logic-based variable time constant second-order high-pass filtering control strategy is proposed for a DC microgrid with hybrid energy storage system (HESS). The fuzzy controller is designed to adjust the filtering time constant according to the real-time State of Charge (SOC) of the supercapacitor, which ensures the SOC of the supercapacitor is within the safety threshold while achieving the frequency division of the hybrid energy storage power distribution and the stable operation of the DC microgrid. Matlab/Simulink simulation results show that the proposed strategy can distribute the power quickly and reasonably, and improve the reliability and stability of the hybrid energy storage system.