State of Charge Estimation of Lithium-Ion Batteries Used in HEV by Enhanced Extended Kalman Filtering

摘要

An equivalent circuit model involving hysteresis characteristics and polarization characteristics of the battery is presented. Extended Kalman filter is used to estimate the state of charge (SOC) of lithium-ion batteries applied in hybrid electric vehicles (HEV). The enhanced EKP comprising optimized gain coefficient is proposed in this paper. Experimental and simulation results compared to EKF only for SOC estimation are presented to demonstrate the precision of the enhanced EKF algorithm for SOC estimation. The proposed algorithm is also suitable for a wide range of working conditions in HEV environments due to its adaptive nature.