Research on Layer Equalization of Lithium Battery Pack Based on Fuzzy Control
To realize battery pack equalization in traditional inductive equalization circuits,energy can only be transferred slowly through adjacent cells but not between any cells.This equalization method is inefficient,and the equalization path and time are long.For this reason,a new hierarchical topology combining Buck-Boost circuit and flyback circuit is proposed.The intra-group equalization uses a bidirectional Buck-Boost circuit,so that the energy is transferred only between two neighboring batteries and the equalization path is short.The inter-group equalization adopts a bidirectional flyback circuit,which controls the switching tubes state of the primary and secondary side windings to transfer energy between the module and the battery packs,to achieve battery pack equalization.A fuzzy control strategy is added in the equalization process to dynamically adjust the duty cycle of the switching tubes to output a suitable equalization current and improve the equalization efficiency.A Matlab simulation model is built for analysis.The simulation results show that the proposed equalization circuit reduces the equalization time by about 18％,22％,and 20％compared with the traditional Buck-Boost circuit in the static,charging,and discharging states,respectively.The improvement of equalization efficiency is of great significance for the future development of multi-lithium battery series connection devices such as electric vehicles.
Lithium battery packEqualization controlBuck-Boost circuitFlyback circuitHierarchical topologyFuzzy control
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维普
