Research on SOC Weighted Control Method of Energy Storage System Based on Fuzzy Logic Control Theory

The equalization system is a key technology in the large-capacity energy storage management system. The existing active equalization and passive equalization can only control the capacity and voltage deviation inside the module (cluster). Although the balance of the SOC in the cluster is realized by the transfer or consumption of the energy in the batteries, the system topology of the large-capacity energy storage is complex and the number of batteries is large. For the entire energy storage system, the overall SOC balance must be considered especially when the system power output demand is close to or exceeds the rated power of the system. The short board cluster will limit the output power capabilities of the overall system. Aiming at the SOC balance of large-capacity energy storage system, this paper allocates the power command sent by the energy storage controller to the energy storage system according to the SOC weighted control algorithm of the fuzzy logic control theory. Through the power control of the bidirectional DC/DC converter, the battery pack whose cluster SOC value is higher than the average value discharge more power in the discharge phase, and the battery pack with SOC value lower than the average value absorbs more energy in the charging stage, resulting the capacity consistency of the battery clusters. Also, the specific implementation steps achieving the SOC weighed control based on Fuzzy logic theory has been illustrated in detail.