A Retired Power Battery Integrated System That Implements Battery Pack SOC Balancing and Fast Balancing Strategy Design

ABSTRACT Retired power batteries with better performance are used as energy storage systems to suppress the power fluctuation of new energy sources, which is conducive to reducing cost and improving resource utilization. However, because the inconsistency of retired power batteries is more serious than that of normal batteries, it is impossible to directly connect them in series or parallel on a large scale. To address this problem, this paper proposes a topology for an integrated system of retired power batteries based on a modular inverter with battery pack state of charge (SOC) balancing capability. The proposed topology consists of a quad active bridge (QAB) converter, a cascaded H‐bridge (CHB) converter, and an AC voltage balancer (ACVB). To address the inconsistency of retired power battery packs, this paper also proposes a fast balancing strategy. The intra‐phase power imbalance of the CHB inverter caused by this method is solved by the ACVB. Finally, an experimental prototype is built, and the effectiveness of the proposed integrated system and fast balancing strategy is verified by experimental results.