Modularized Equalization Architecture With Transformer-Based Integrating Voltage Equalizer for the Series-Connected Battery Pack in Electric Bicycles

Bin Xu, Lizhou Liu, Zhaotian Yan, Zhuqing Yuan, Lu Zhang, Wei Zhou, Ruikun Mai, Zhengyou He, Yongpan Liu, Huazhong Yang

Abstract: Due to the electrical isolation, fewer switches, and easy control, the transformer-based integrated equalizer is promising in commercial applications. However, few balance energy transmission channels limit the transformer-based integrated equalizer applied to the long battery string. Therefore, a integrated voltage equalizer with a modularized architecture (MEA-TE) is proposed. The proposed equalizer increases the energy transmission channels, which realizes the balance for the long battery string. The modularized equalizer consists of three parts: the dc–dc converter, the converter-to-module transformer (CMT), and the module-to-cell transformers (MCT). The mosfet in the dc–dc converter drives the CMT, and the CMT drives all the MCTs to balance each cell. The proposed MEA-TE equalizer only uses one mosfet to balance the large battery pack. The MEA-TE platform for eight battery cells is established. The results demonstrate that the MEA-TE equalizer can realize the balance of the large battery pack.