Health State Equalization Control Strategy for Multi-battery Clusters in Energy Storage Systems

Abstract

To address the issue of health state equalization among multiple battery clusters in energy storage systems, this paper designs a multi-battery cluster health state equalization control strategy for the energy storage system. This strategy sets the minimum grid-connected power limit for the storage converter according to the change rule of battery life and the grid connection requirements and determines the number of storage converter units involved in the operation of the system based on this limit. Furthermore, the hierarchical analysis method is combined to evaluate the health state of the various clusters of batteries involved in the operation and quantify the value to get the weight coefficients and corresponding power sizes of the storage converter to assume the grid-connected power command. The number of participating energy storage converters and the transmitted power are adjusted to ensure that the power of each energy storage converter does not exceed the limit. Compared with the equalization control strategy, the proposed control strategy can effectively equalize the health state of each battery cluster, extending the overall service life of the energy storage power plant by 40.6% and effectively improving the safety and economy of the energy storage power plant.

Keywords

• energy storage system
• battery life change rule
• energy storage converter
• hierarchical analysis method
• safety
• economy