Direct Torque Control for Electric Vehicle Driver Motor Based on Extended Kalman Filter

There are some problems of torque ripples and flux ripples and current ripples in traditional direct torque control (DTC). System with speed sensor has lower reliability and higher system cost. To solve these problems, an extended Kalman filter(EKF) was established to observe stator flux linkage and estimate motor speed, thus speed sensorless direct torque control for asynchronous motor was realized. The deficiencies of integrator in traditional DTC were overcome. Rapid torque response and strong robustness of direct torque control method were still maintained. Meanwhile, the system based on EKF is robust to motor parameters variation and load disturbance. The dynamic and static system performances were dramatically improved. The simulation and experiment results have verified the feasibility and effectiveness of this method.