Fuzzy control for hybrid energy storage system based on battery and Ultra-capacitor in Micro-grid

This paper mainly presents the research results on hybrid energy storage system in a Micro-grid with a DC Bus and an AC bus in it. The storage system is based on battery and Ultra-capacitor. When a sudden load is switched into the Micro-grid, the voltage of the DC Bus should be maintained to avoid stability problems. To fulfill the requirement, a parallel structure of two bi-directional DC/DC converters has been chosen and also a fuzzy control method has been proposed. Simulation results have proved that the energy storage system designed and the control method are applicable and effective for the Micro-grid.