A Two-Level Active Equalization for Battery Packs Using Breadth First Search Algorithm

Equalization management is an effective approach for addressing energy inconsistencies in battery systems, and active equalization has emerged as the dominant direction for battery equalization management due to its low energy consumption and high efficiency. In this study, we propose a two-level active equalization scheme for battery packs, employing the Breadth First Search (BFS) Algorithm. Firstly, a flexible reconstruction topology is introduced to enable a two-layer balancing scheme. Specifically, a switched capacitor scheme is used to balance cells within modules, while the module balancing is achieved through flexible reconstruction. Subsequently, the equalization process is modeled using graph theory, and an equalization strategy based on the BFS algorithm is developed to determine the optimal energy path. Finally, the proposed balancing scheme is compared with traditional switched capacitor balancing schemes. Experimental results demonstrate that the proposed scheme exhibits superior balancing performance, with an optimal switching period of 2 seconds and a duty cycle of 55%.