结合变压器正反激原理的动力电池主动均衡方法

An active equalization method combining the forward and flyback principles of transformer is designed to solve the problem of the inconsistent battery states of power batteries. Firstly, a transformer is utilized as an energy transfer device to realize the modularization of the equalization system of a battery pack. Batteries in the equalization module are equalized by the forward principle of transformer, while the module and the battery pack are balanced by using the flyback principle of transformer. Then, it depends on the direction of the charge transfer that two equalization modes of energy transfer can be implemented, i. e., energy transfers from the battery pack to the equalization module or from the equalization module to battery pack. Finally, a control strategy based on battery voltage is used to judge the voltage state of batteries and to select a corresponding equalization mode so that the synchronous equalization of different equalization modules is achieved. A battery equalization experimental platform is established, and effectiveness of the proposed equalization method and the control strategy are verified under the static condition and the Urban Dynamometer Driving Schedule. Results and a comparison with the traditional transformer-based equalization method show that the proposed equalization method has a faster equalization speed, and its average equalization speed is 0.097 mV/s.