Fuzzy Based Management of Hybrid Energy Storage System for Improved Dynamic Response of DC Microgrid

The intermittent and fluctuating nature of photovoltaic(PV) sources is the main concern for large scale integration into the distribution system. Fast acting hybrid energy storage system(HESS) plays a vital role to overcome the intermittency and reliability characteristics associated with PV integration in microgrid environment. The battery handles long-term power variation while transient power is controlled by the supercapacitor(SC). In this paper a fuzzy based dynamic energy management is proposed for the improved performance of a DC microgrid. A fuzzy logic control(FLC) strategy is implemented to determine the optimal charging/discharging of the HESS, by generating the required reference currents. The microgrid performance is evaluated for a randomly varying irradiance profile and step variation of irradiance and load. In both scenarios, the HESS with FLC control responds well to balance the power flow by maintaining constant DC voltage at 400V and by continuously checking the SoC limits. The system performance with and without the supercapacitor is also analyzed. The simulation results substantiate the efficiency of the FLC and emphasize the significance of using HESS as well.