Research on Hybrid Natural and Forced Active Balancing Control of Battery Packs State of Charge Based on Unscented Kalman Filter

To reduce the inconsistency of battery packs, to enhance the overall performance of battery packs, and to prolong electric vehicle mileage an innovative balancing converter for the lithium battery pack is proposed in this paper. During the driving process of an electric vehicle, this topology makes it convenient to transfer extra energy from one cell to any other cells, namely, active pack management composed of improved bidirectional DC-DC converters which are presented with the Hybrid Natural and Forced Active Balancing Control (HNFABC). According to HNFABC, the simulation model of the balancing circuit is built with four batteries in Matlab/Simulink. The simulation results show that HNFABC is not only better than the other traditional balancing control strategies but also reduces the energy loss in the balancing process.