Abstract:Aiming at the problem of energy inconsistency during the charging and discharging process of lithium battery packs, this paper proposes a two-level equilibrium topology, which is divided into inner and outer groups. The inductance-based ring structure equalization circuit is used in the battery pack, which realizes a new type of active equalization of bidirectional ring transfer of energy between adjacent single cells and the head and tail cells. A centralized balance topology based on a single inductor is used outside the battery pack, which can achieve balance between any battery packs between the packs. In terms of balancing control strategy, taking the battery state of charge as the balancing variable, a fuzzy logic control algorithm is designed to dynamically adjust the balancing current to reduce the balancing time and improve the balancing efficiency. Using MATLAB/Simulink software to build and simulate the model, the experimental results show that the energy transfer topology proposed in this paper reduces the equalization time by 24.46% compared with the traditional Buck-Boost circuit energy transfer topology between adjacent cells. In addition, compared with the fuzzy logic control algorithm using the fuzzy logic control algorithm under static and charge-discharge conditions, the standard deviation of single cells after equalization decreased by about 11%. The feasibility of the equalization scheme is verified.