PMSM speed sensorless direct torque control based on EKF

System with mechanical speed sensor has lower reliability and higher cost. Traditional direct torque control method has disadvantages of big ripples on current and flux linkage and torque. To solve these problems, the Extended Kalman Filter is established to estimate both stator flux linkage and rotor speed. Therefore, speed sensorless direct torque control for surface permanent magnet synchronous motor is realized. Simulation results have shown that the advantage of direct torque control method such as rapid torque response is maintained, at the same time, the system based on EKF is robust to motor parameters and load disturbance. The dynamic and static performances are dramatically improved.