Research on active equalization technology of retired battery based on SOC

An equalization circuit is designed to solve the inter group equalization problem of parallel battery packs. The AC is changed into DC by the front three-phase PWM rectifier circuit, and then each group of batteries is connected through multiple DC / DC circuits in the rear stage. Each battery unit corresponds to a DC / DC circuit. The charge and discharge current of each battery pack is changed through the coordinated control strategy based on SOC, so that the state of charge (SOC) of different groups of batteries gradually tends to be consistent in the process of charge and discharge, The simulation results show that this method can effectively realize the equalization between battery packs with different consistency.