Research On Distributed Cooperative Control Strategy Of Energy Storage Unit In Microgrid

As a two-way flow device that can store or release energy,energy storage system can not only promote the utilization of renewable energy,but also improve the utilization efficiency of power equipment and the economic operation of power grid.In recent years,with the continuous infiltration of renewable energy,the energy storage system has gradually become large-scale.The traditional centralized control method is limited by the control center,and it is unable to achieve effective scheduling of small-scale distributed energy storage systems in the microgrid.Therefore,a distributed cooperative control strategy based on multi-agent consistency algorithm is studied in this paper.This strategy can not only solve the scheduling problem of large-scale energy storage system,but also can make the total system cost low.The details are as follows:The relationship between the cycle life of the storage battery and its discharge depth is analyzed,and the discharge cost model of the battery storage system is established.Aiming at the characteristics of decentralized energy storage system,a distributed cooperative control strategy of energy storage units is proposed.Considering the life cost of energy storage battery during each discharge,the incremental cost of energy storage battery is seen as the variable in the multi-agent consistency algorithm and then a distributed scheduling model of energy storage unit is established.Through the interaction of local information between two adjacent energy storage units,the optimal distribution of power in the energy storage system is realized.This strategy can maximize the peak shaving characteristics of energy storage system,reduce the calling cost and ensure the economic operation of the system.The aggregation characteristics of small-scale mobile energy storage clusters are studied.According to the response characteristics of energy storage clusters under different power distribution,the aggregation response model is fitted by the least square method.The multi-agent system consistency algorithm is adopted to design a hierarchical distributed control strategy for small-scale energy storage clusters.The strategy is divided into two layers.The lower layer divides the small-scale energy storage clusters into different blocks according to the regional relations,and establishes the aggregation response model of the corresponding blocks.The upper layer adopts the multi-agent consistency algorithm.According to the different aggregate response model under different power distribution situations,the best allocation of the total power between the various blocks is obtained.This strategy realizes bidirectional flow of energy between the mobile energy storage unit and the grid and ensures the optimal economic deployment of the energy storage system cluster.The energy storage unit distributed collaborative control strategy is verified by simulation software.The simulation results show that the distributed control strategy proposed in this paper can not only ensure the energy storage system make response timely to the power demand of the power grid,but also minimize the total cost of the system.Further,the stability and economy of the system can be effectively improved,and the feasibility and effectiveness of the distributed consistency algorithm in dealing with the scheduling problem of small-scale energy storage cluster is proved.