Distributed Secondary Control Strategy for Battery Storage System in DC Microgrid

In this paper, a distributed secondary control strategy is proposed to achieve accurate load current sharing and DC bus voltage recovery for battery energy storage system (BESS) in DC microgrid. Firstly, each battery energy storage unit (BESU) is regarded as a multi-agent, and a neighbor-to-neighbor sparse communication network architecture is constructed. Each BESU is based on distributed consensus protocol, and global consensus can be achieved only by communication between adjacent BESUs. On this basis, a state of charge (SoC) equalization algorithm is proposed to achieve accurate load current sharing, and a DC bus voltage controller is designed to achieve secondary regulation of the bus voltage. Finally, the simulation results show that the proposed strategy reaches the expected control objectives under various operating conditions of the microgrid.