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QIANG Jiaxi
AO Guoqiang
YANG Lin
School of Mechanical Engineering,
Shanghai Jiaotong University,
Shanghai 200030, China
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ESTIMATION
METHOD ON THE
BATTERY STATE OF CHARGE FOR
HYBRID ELECTRIC VEHICLE*
Abstract:
A combined algorithm for battery state of charge (SOC) estimation is proposed to solve the critical issue of hybrid electric vehicle (HEV). To obtain a more accurate SOC, both coulomb-accumulation and battery resistance-capacitor (RC) model are weighted combined to compensate the deficiencies of individual methods. In order to solve the key issue of coulomb-accumulation, the battery thermal model is used. Based on the principle of energy conservation, the heat generated from battery charge and discharge process is converted into the equivalent electricity to calculate charge and discharge efficiency under variable current. The extended Kalman filter (EKF) as a closed loop algorithm is applied to estimate the parameters of resistance-capacitor model. The input variables do not increase much computing difficulty. The proposed combined algorithm is implemented by adjusting the weighting factor of coulomb- accumulation and resistance-capacitor model. In the end, four different methods including Ah-efficiency, Ah-Equip, RC-SOC and Combined-SOC are compared in federal testing procedure (FTP) drive cycle. The experiment results show that the proposed method has good robustness and high accuracy which is suitable for HEV application.
Key words:
State of charge Coulomb-accumulation Resistance-capacitor model
Hybrid electric vehicle
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* This project is supported by National Hi-tech Research and Development Program of China (863 Program, No. 2002AA501732) and National Basic Research Program of China (973 Program, No. 2007CB209707). Received March 20, 2007; received in revised form March 8, 2008; accepted April 7, 2008 |
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Biographical notes
QIANG Jiaxi is a PhD candidate in Shanghai Jiaotong University, China.
Research field includes character and performance of Ni/MH and Pb
batteries for hybrid electric vehicle, algorithm of SOC estimation, and
the design and implementation of battery package management system.
Tel: +86-21-34206365; E-mail: qiangjiaxi@sjtu.edu.cn
AO Guoqiang is a PhD candidate in Shanghai
Jiaotong University, China. Research field includes system architecture
efficiency of the hybrid electric vehicle, calibration and CAN
communication protocol of HEV control system, and the design and
implementation of HEV bench test.
Tel: +86-21-34206365; E-mail: aoguoqiang@sjtu.edu.cn
YANG Lin is a professor, and wined his PhD
degree at the ICE major from Shanghai Jiaotong University, China, in
1997. He engaged in advanced studies in ISUZU Motors Limited of Japan in
1999. He was promoted to the associate professor in 2000, and the
vice-director of the Institute of Automobile Electronic Technology,
Shanghai Jiaotong University, China, in 2002. Now, he is taking charge
of two projects sponsored by National Hi-tech Research and Development
Program of China (863 Program). His research interests include the HEV
powertrain and its control, the HEV battery and its management system,
the electronic control of the internal combustion engine.
Tel: +86-21-34206365; E-mail: yanglin@sjtu.edu.cn
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