Simulation and experimental studies of model reference adaptive system for sensorless induction motor drive

This paper presents a model reference adaptive system-based sensorless induction motor drive. In this scheme, an adaptive pseudoreduced-order flux observer is used instead of the adaptive full-order flux observer. The simulation and experimental results show that with the large PI gains for the adaptive scheme, the convergence for the speed estimation is fast, however, higher order harmonics and noises are included in the estimated speed. Usually noises caused by A/D converters and hysteresis current controller. Since the current measurement is noisy, therefore large values of adaptive scheme gains cause the estimated flux and consequently the estimated speed noisy. The desired gains are a trade-off between a high speed of response, and high robustness to noise. Simulation and experimental results show that proposed scheme can estimate the motor speed under various adaptive PI gains and estimated speed can replace to measured speed in sensorless induction motor drives.