An improved sensorless vector-control method for an induction motor drive

• Published in: IEEE transactions on industrial electronics (1982) Vol. 52; no. 6; pp. 1660 - 1668
• Main Authors: Mitronikas, E.D., Safacas, A.N.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.12.2005; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Adaptive systems; Direct control; field-oriented control; induction machine; Induction motor drives; Logic; Microcontrollers; Optimal control; Rotors; Sensorless control; Stability; stator-flux orientation; Stators; Studies; Velocity control
• ISSN: 0278-0046; 1557-9948
• DOI: 10.1109/TIE.2005.858706

In the present paper, a new improved sensorless vector-control method for an induction motor drive is presented. The proposed method is based on an improved closed-loop stator-flux estimator, based on the dynamic model of the asynchronous motor, which achieves precise stator-flux estimation over a wide area of operation. This new stator-flux estimator ensures stability of the overall control scheme in a very-wide-speed operation area, as it will be shown in this paper. The rotor-speed-estimation method is based on an observer based on the model reference adaptive systems (MRAS) theory. The control scheme is based on a stator-flux-oriented direct vector-control method, where both flux and speed controllers are optimal tuned. In addition, implementation of the proposed method is based on a simplified algorithm capable of running in a low-cost microcontroller, which is discussed in detail. Also, the motor-drive system, including the stator-flux estimator, the speed estimator, and the control logic are simulated and some characteristic simulation results are presented. These results reveal that the proposed method is able to obtain precise flux and speed control over a wide operation area, including very low operating frequencies.