A novel multimode constant magnetizing current battery equalizer with few sensors in electric vehicles

Abstract

The conventional automatic battery equalizer is characterized by its low cost in batter management system. However, its effectiveness is limited by the absence of signal feedback, leading to inadequate self‐regulation and protection of the topology. In this paper, an equalizer with constant magnetizing current is proposed. By adjusting the duty cycle of the MOSFETs, the magnetizing current can be flexibly controlled, which greatly improves the equalization rate and safety. The topology has multiple modes such as cell to cell (C2C), cell to string (C2S), and string to string (S2S). A creative signal sampling method is designed to obtain the cell voltage and magnetizing current with few sensors. And a novel balancing strategy is proposed, which can achieve wonderful accuracy of equalization at any initial voltage distribution.