A New Centralized Equalizer with a Simpler Control Strategy for Series-Connected Batteries

Abstract

The centralized equalizer has a good prospect in the mobile battery system due to its small size and light weight. However, equalizers with a centralized structure generally need a tricky balancing strategy and have an improbable balancing performance. This paper proposes an equalizer with multi-modes. It has a more straightforward balancing strategy than conventional equalizers with a centralized structure. This allows it to deal with the problem of inconsistency in a battery string more effectively without repeated actions of the switch matrix. Moreover, the merits of conventional equalizers with a centralized structure, such as being low-cost and compactness, remain in the proposed scheme. The operating principle, balancing strategy, and balancing efficiency are analyzed in detail. An experimental prototype for a battery string containing four cells is implemented after simulations. Experimental results validate that the proposed equalizer can balance a battery string with an efficiency of 81.7%.