SOC Balancing Method for Hybrid Energy Storage System in Microgrid

Abstract

The SOC balancing problem is an important question in energy storage system. Up to now, the SOC balancing control for hybrid-type energy system has not been documented. To deal with the SOC balancing problem for the complex hybrid-type energy storage system. This paper proposes a SOC balance control which uses centralized control for local units in cascaded-type energy storage system and modified droop control to adjust the performance of cascaded-type energy storage system together. In this scheme, regardless of charging mode or discharging mode, the proposed control can work well and the SOC balancing is guaranteed. Finally, the theory analysis and simulation results can prove the correctness and effectiveness of SOC convergence among all storage units in entire system under proposed control.