A Distributed SoC Balancing Control Method for Series-type Energy Storage System in Grid-connected Mode

Energy storage system (ESS) equipped with power electronics plays an essential role in renewable energy integration. Series-type energy storage system (SESS) is deemed to have broader application perspectives for its advantages on bulking voltage level without transformers. The synchronization and SoC balancing between series-modules is vital for SESS application. Existing researches mainly focus on centralized control, which has strict requirement for communication safety and bandwidth. To fill this gap, a distributed SoC balancing control method is proposed for SESS in grid-connected mode. Through this method, the SoC balancing and synchronization can be realized in both charge and discharge mode. An average SoC estimator is designed based on dynamic consensus control, which only relies on the communication between adjacent neighbors. And simulation results under different conditions are carried out to verify the effectiveness of the proposed method.