A Bus-Based Battery Equalization via Modified Isolated Cuk Converter Governed by Adaptive Control

Active equalization systems require balancing current regulation to further improve balancing efficiency and battery cycle life. This paper focuses on an adaptive control strategy for a battery equalization system based on modified isolated Cuk converter. Firstly, the analysis and modeling of the modified isolated Cuk-based equalizer are presented, and then the development of the adaptive sliding-mode control (SMC) scheme is proposed. The designed controller is verified through testing transient response, reference current variation and load change under continuous conduction mode. Compared with a traditional SMC, the proposed adaptive control has strongly ability to cope with the external disturbance and system parameters variation. A bus-based battery equalization system for five cells in series with an unbalanced state-of-charge (SOC) 0.75, 0.90, 0.45, 0.80 and 0.67 is performed to test the proposed control method. The simulation results indicate that the battery pack reaches to a balanced state in 712 sec.