Speed Sensorless Field-Oriented Controlled IM with Stator Voltage Error Compensator

Abstract

This paper shows a speed sensorless field-oriented controlled induction motor with a stator voltage error compensator. The speed sensorless field-oriented control needs the measurements of terminal voltages, but the measuring of the instantaneous voltage at the output of a PWM voltage source inverter has difficulty due to harmonic noise, dead time effects, etc. Also the degree of accuracy of voltage measurement deteriorates in low speed range. In order to overcome these problems, the reference voltage is utilized for the observer input in our method, and the error between the reference and the actual voltages are compensated by the estimated voltage error which is in a part of the adaptive observer system. This method improves the accuracy of speed sensorless system without voltage sensor.