Control Strategy Of Hybrid Energy Storage And Optimize Configuration For Microgrid

In recent years,distributed source has developed rapidly,but the randomness and volatility of the output power of the distributed power have negative impacts on the power quality and power supply reliability.In order to improve the influence of distributed energy natural defect on power grid and improve power quality,energy storage system is used to reduce the fluctuation of distributed energy and become the main force of development.Most of the current micro grid use battery as energy storage devices,but only use energy storage may lead the capacity to redundancy and repeated charge/discharge will reduce the life of battery,so the combination of power type energy storage and energy type energy storage is the hot spot of research.Based on the stability and economy of energy storage system,the control strategy and capacity allocation method based on lead-acid battery and super capacitor hybrid energy storage system are studied in this paper.The details are as follows:Firstly,the research status of hybrid energy storage is introduced in this paper.the hybrid energy storage system of battery(energy element)and super capacitor(power element)is taken as the research object,the detailed working principle is analyzed,and the advantages of hybrid energy storage system relative to single energy storage are expounded.The mathematical model of DC-DC converter is established.Secondly,the energy allocation strategy of hybrid energy storage system based on fuzzy control is proposed.The strategy adjusts the filter time constant T in real time through fuzzy controller based on low-pass filter,in order to coordinate the compensation power of the two hybrid energy storage units,reduce the power fluctuation of the battery,and prolong the service life of the battery.In the meantime,in order to prevent overcharge and overdischarge of both batteries,the compensation power is dynamically adjusted by the state of charge SOC of the storage battery.Finally,in order to further improve the system economic,research on the capacity configuration of hybrid energy storage system and establish the minimum life cycle cost of the objective function,using genetic algorithm to obtain the power,capacity and configuration of batteries and super capacitors under different power supply reliability standards,and to calculate the cost of hybrid energy storage.The simulation results show that the hybrid storage system of battery and super capacitor can achieve rational distribution of wave power and stabilize power fluctuation of wind power effectively stabilize,the optimal allocation of hybrid storage system capacity can reduce the investment of microgrid,prolong the service life of the hybrid energy storage and ensure the stability and economy of the system.