Battery Equalization Using Bi-directional Cuk Converter in DCVM Operation

A systematic approach to the analysis and design of a bi-directional Cuk converter for the cell voltage balancing control of a series-connected battery string is presented in this paper. The proposed individual cell equalizers (ICE) are designed to operate at discontinuous-capacitor-voltage mode (DCVM) to achieve the zero-voltage turn-off switching (ZVS) for reducing the switching loss of the bi-directional DC/DC converters. Simulation and experimental results show that the proposed battery equalization scheme can not only enhance the bi-directional battery equalization performance, but also can reduce the switching loss during the equalization period. The switch power is significantly reduced by about 52.8% from MOSFETs and the equalization efficiency can be improved by 68-72% using the proposed DCVM ZVS battery equalizer under the specified cell equalization process