Speed and Load Torque Identification of the Induction Motor by Using EKF

A novel method to estimate the rotor speed and load torque was proposed for the sensorless control system of the induction motor,which was based on extended Kalman filter(EKF).The system adopted the vector control technique.The motion relationship was regarded as a state equation,and the load torque was taken as an extended state of the system by using the EKF.So the rotor speed,load torque and rotor flux can be estimated based on the stator currents and stator voltages according to the proposed EKF.Simulation results showed the good performance of the control system and the good estimating performance of these variables even during the low speed region.