Bi-Directional Cuk Equalizer-Based Li-Ion Battery Pack Equalization Control Strategy Research

Abstract

For the secure usage of battery charging and discharging within electric vehicles, the study of cell pack equalization technology is essential. Therefore, in this paper, an improved Bidirectional Cuk equalizer (BCEQ) structure based on a variable-domain fuzzy PID (VFPID) control equalization strategy is recommended in stages. With the new equalization topology, only half of the capacitive and inductive components are needed to transfer energy between any two individual cells in the power supply. In addition, the proposed VFPID control strategy further improves the efficiency of the equalization model by dynamically adjusting the magnitude of the equalization current parameters. Through simulation experiments, the improved topology was capable of substantially lessening the equalization time and increasing energy utilization by more than 4%. In comparison with the fuzzy PID (FPID) algorithm, around 27.3% faster equalization times can be achieved with the VFPID algorithm; the VFPID algorithm also performed well under the Dynamic Stress Test (DST) condition, demonstrating that the topology and equalization strategy suggested in this paper can successfully address the inconsistency of the FPID algorithm. It has been revealed that the topology and equalization methodology offered in this paper is effective in solving the battery pack inconsistency.