Research on active state of charge balance of battery pack based on two controllable flyback converters

Abstract

Usually, the capacity of a single battery is small, so it is often used in series/parallel to form a battery pack to improve the power supply capacity. In this case, with the use of the battery, the performance of each battery will gradually become inconsistent, resulting in an imbalance of the battery’s power, which will cause overshoot or overdischarge of the single battery. In order to solve this problem, based on the controlled source equivalent replacement second-order model, an equalization scheme is proposed that uses the SOC estimated by the 5th-order VBSRCKF as the equalizing variable and the closed-loop flyback converter as the energy transfer circuit to make the power of each battery pack tend to be similar. The experimental results show that this scheme can effectively solve the problem of inconsistent battery energy caused by inconsistent battery performance, and the equalizing current can be controlled and the equalizing speed can be controlled, which can better protect the batteries.