This paper proposes an equalization system for the secondary use of retired battery. First, the proposed converter in the system is characterized by its low cost, achieved through the utilization of the reconfigurable structure. Moreover, the SOC balancing strategy is proposed to regulate the equalization current based on the SOC state, facilitating effective equalization control of the retired battery pack. In addition, the small signal model is established to design the close-loop control strategy. The strategy can enable the retired batteries to achieve equalization while regulating the dc bus voltage of dc microgrid. Finally, the effectiveness of the proposed system is verified through simulation.

retired battery, SOC balancing, small signal model, dc microgrid