A novel MRAS based speed sensorless control of induction motor

Speed and torque control of an induction motor is usually attained by application of a speed or position sensor. However, speed and position sensors require the additional mounting space, reduce the reliability in harsh environments and increase the cost of the motor. Various control algorithms have been proposed for the elimination of speed and position sensors. This paper investigates a novel speed sensorless control of an induction motor. The proposed control strategy is based on MRAS (model reference adaptive system) using state observer model with current error feedback and rotor current model as two models for flux estimation. The rotor speed is estimated so that the difference between the outputs of state observer model and rotor current model may be zero. This algorithm may overcome several shortages of conventional MRAS: integrator problems, small EMF at low speed, and relatively large sensitivity to resistance variation. The proposed algorithm is verified through simulation and experiment.

[1]  Peter Vas,et al.  Sensorless vector and direct torque control , 1998 .

[2]  C. Schauder,et al.  Adaptive speed identification for vector control of induction motors without rotational transducers , 1989, Conference Record of the IEEE Industry Applications Society Annual Meeting,.

[3]  Tadashi Fukao,et al.  Robust speed identification for speed sensorless vector control of induction motors , 1993, Conference Record of the 1993 IEEE Industry Applications Conference Twenty-Eighth IAS Annual Meeting.

[4]  Kaushik Rajashekara,et al.  Sensorless control of AC motor drives : speed and position sensorless operation , 1996 .

[5]  Francesco Profumo,et al.  Comparison of different schemes without shaft sensors for field oriented control drives , 1994, Proceedings of IECON'94 - 20th Annual Conference of IEEE Industrial Electronics.

[6]  J. Holtz.  State of the art of controlled AC drives without speed sensor , 1995, Proceedings of 1995 International Conference on Power Electronics and Drive Systems. PEDS 95.