Title: Power battery SOC estimation with combination method based on UKF and open circuit voltage

Authors: Junzhao Zhou; Xiangwen Zhang

Addresses: School of Electrical Engineering and Automation, Guilin University of Electronic Technology, Guilin 541004, China ' School of Electrical Engineering and Automation, Guilin University of Electronic Technology, Guilin 541004, China

Abstract: The state of charge (SOC) is an important parameter in the battery management system. The SOC is usually estimated with the battery voltage and other state. Owing to the initial value problem of SOC, the estimation error may increase greatly. In order to solve this problem, the combination method based on unscented Kalman filter (UKF) and open circuit voltage is proposed in this paper. First, the PNGV model is used, and its parameters are identified with HPPC test data. Then, the estimation process is proposed. In order to verify the method, the PNGV battery model is established in the Simulink Toolbox. With the battery model, the SOC combination estimation method was simulated and compared with Ah counting and extended Kalman filter (EKF) methods. The simulation results show that the combination method gives smaller estimation error and calculation amount, so the combination estimation method is promising and useful for estimating the battery SOC.

Keywords: battery management systems; SOC; state of charge; open circuit voltage; unscented Kalman filter; UKF; PNGV model; simulation.

DOI: 10.1504/IJEHV.2014.065727

International Journal of Electric and Hybrid Vehicles, 2014 Vol.6 No.3, pp.215 - 226

Received: 24 Dec 2013
Accepted: 09 Jul 2014
Published online: 11 Nov 2014 *

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