SOC Estimation of Power Battery in Electric Vehicle Based on MC9S12DG128

This paper explored how to make use of extended Kalman filter (EKF) technique to estimate the state of charge (SOC) of battery. Based on the equivalent circuit model of battery, a mathematical model of EKF was established, and an EKF algorithm of SOC estimation was presented. By single chip microcomputer (MCU) of MC9S12DG128, a hardware platform for experimenting with this algorithm was built up. Then this algorithm was verified by two kinds of discharge tests on the hardware in the loop platform. The test results show that this algorithm is able to satisfy the requirement of SOC estimation. It has a high accuracy, and a low error accumulation.