Centralized control of parallel connected power conditioning system for battery energy storage system in charge-discharge-storage power station

This paper presents a centralized control system that coordinates parallel operations of power conditioning system (PCS) for battery energy storage system (BESS) in charge-discharge-storage power station. An overall energy management system is implemented to optimize power flow among different battery energy storage systems during both grid-connected and islanded operations. In islanded mode, the traditional load sharing strategy will result in battery aging and increased circulation if the state of charge (SOC) of each battery is different. Therefore, a power allocation strategy based on SOC and module capacity is designed, which can make full use of the total capacity of the parallel system. The design concept of the proposed centralized control system is evaluated through simulation and experiment studies under different test scenarios.