Power sharing for distributed energy storage systems in AC microgrid: Based on state-of-charge

The approach to optimal control for distributed energy storage systems has been an issue of interest in recent years. In this regard, the performance of power sharing between Energy Storage Units (ESUs) with different States of Charge (SoC) can be enhanced. In this paper, the SoC of each ESU is balanced using the proposed control method, which is decentralized and based on the adaptive droop control method. The droop coefficient should be adjusted in the system on the basis of the SoC of each ESU. With this control strategy, the storage unit with higher SoC provides more power to support the load, while the unit with lower SoC provides the less power. The method is validated using simulation results from PSCAD/EMTDC software.