Research On The Control Strategy Of Hybrid Energy Storage And Multi Energy Storage System For Microgrid

The micro grid can integrate the distributed power supply,load and energy storage devices effectively,so as to provide power to local users flexibly,economically and reliably.The key to realize the stable operation of the microgrid system is to plan,design and develop a reasonable control strategy for the capacity of the system.As an important part of the stable operation of the microgrid,the energy storage system can stabilize the voltage and frequency of the microgrid through the exchange of energy.In this paper,the energy storage system of micro grid is taken as the research object.The main work is as follows:Firstly,the working principle of the lead-acid battery and the super capacitor is analyzed in detail,and the mathematical model of the DC-DC converter is established.In order to improve the utilization ratio of super capacitor,reduce the use frequency of battery and prolong its service life,the energy allocation strategy is put forward for the hybrid energy storage system of super capacitor and battery.At the same time,considering the charge state of the two kinds of batteries,the power output can be adjusted dynamically,and the charge state of the two energy storage batteries can be kept consistent.Next,in order to reduce the large fluctuations in the micro grid caused by sudden failure or access of high-power load,this paper uses the power feed-forward control strategy of energy storage system that the energy storage system can respond in a timely manner when the power fluctuation occurs to maintain the stable operation of the micro grid and improve the security and stability of the micro grid.Finally,several control methods are introduced,including master-slave control,peer control and hierarchical control.In view of the parallel operation of multiple energy storage systems,a multi master slave control strategy for microgrid is proposed.The conventional P/Q control,V/F control and Droop control are improved to form P/Q-Droop control and V/F-Droop control.It can take advantage of Droop control and V/F control advantages together to improve the stability of micro grid.The simulation results verify the feasibility of the control strategy.