A robust speed controller for speed sensorless field-oriented controlled induction motor drives

Sensorless field-oriented control of induction motors is widely used in high-performance applications. However, the decoupled control may be detuned due to the motor parameter variation and load torque disturbance. In this paper, a new fuzzy PI self-tuning robust speed controller with feedforward control of an adaptive disturbance observer is proposed for sensorless induction motor drives to ensure designed dynamic performance. First, the dynamic model of field-oriented controlled induction motor considering the parameter and load torque disturbance is analyzed. Then the adaptive disturbance observer for feedforward control is designed to obtain satisfactory dynamic response by realizing the uncertainty compensation for parameter variations and external load disturbance. The compensation signal is obtained based on the model reference adaptive system theory. And the fuzzy self-tuning PI speed controller is designed according to the prescribed command-tracking specifications. The validity of the proposed robust speed controller is verified by speed sensorless field-oriented vector control of 11 kW induction motor. Experimental results show that the proposed speed controller ensures good robustness and adaptability under modeling uncertainty and external disturbance.