Modeling and energy management strategy of hybrid energy storage in islanded DC micro-grid

The depletion of fossil fuels has triggered a search for renewable energy. Electrolysis of water to produce hydrogen using solar energy from photovoltaic (PV) is considered one of the most promising ways to generate renewable energy. In this paper, a coordination control strategy is proposed for the DC micro-grid containing PV array, battery, fuel cell and proton exchange membrane (PEM) electrolyzer. For electrolytic cell, the maximum efficiency is obtained by deducing the energy conversion efficiency of PEM electrolyzer. Combined with the storage of hydrogen in hydrogen storage equipment, an adaptive power conversion control approach is proposed. For the battery and supercapacitor (SC), the state of charge (SOC) and over charging and discharging power are considered to avoid the influence of excessive power and over charge and discharge on the device life span. For fuel cells, when the battery and SC cannot meet the power demand, the power supply is carried out with constant power control scheme. The validity and correctness of modeling and control strategies referred in this paper are verified through simulation results based on MATLAB/Simulink software platform.