Model-based Design Methodology for an Active Equalization Circuit based on a Multi-winding Transformer

Nowadays, cell balancing circuits are fundamental for maximizing the usable capacity of a battery pack and preventing possible hazard conditions. Despite passive equalizers are widely adopted in industrial and vehicular applications due to their reliability and cost, active balancing circuits are becoming more attractive thanks to the improvements achievable in terms of efficiency and equalization speed. In this paper, a model-based design methodology for an active equalizer based on a Multiple Active Bridge (MAB) is illustrated, including the harmonic content introduced by the related power conversion stages. In detail, the proposed methodology aims to size the parameters of the multi-winding transformer included in the MAB architecture that allow for ensuring the desired performances in terms of balancing currents and RMS winding currents. Numerical results are presented for validating the proposed methodology.