Study on rotor flux oriented speed sensorless vector control method of induction motor

Speed sensorless vector control is the key technique in high performance application. In order to improve the performance of speed estimator at low speed, a speed sensorless control method based on a novel vector control is proposed. Rotor flux orientation is adopted to realize flux and torque decoupling. Speed estimation is obtained according to the error information of torque through a proportional integration adaptive mechanism based on the theory of model reference adaptive control (MRAC). It is demonstrated that estimated speed can trace the real speed very quickly and good performance is attained in low speed range.