Research on Active Equalization Strategy of Retired Batteries for Microgrid Energy Storage Systems

Retired power batteries are wired in series and parallel to create sizable battery packs for microgrid energy storage applications that necessitate more rigorous equalization management during operation. In this paper, the real-time estimation of the state of charge (SOC) of batteries is achieved through the establishment of an equivalent model of retired power batteries and the adoption of the extended Kalman filter method. A bidirectional active equalization structure is employed, wherein the SOC serves as the equalization variable. To achieve inter-battery equalization between battery packs, an inductive equalization topology and a differential fuzzy control equalization strategy are utilized. The results of the simulation analysis demonstrate that the proposed equalization method is an effective and expedient approach for addressing the inconsistency issues observed in retired battery packs.