Comparison of sensorless techniques based on Model Reference Adaptive System for induction motor drives

This paper presents a comparison of sensorless vector control strategies for Induction Motor (IM). The strategies includes an Indirect Field Orientation Control (IFOC) and a Model Reference Adaptive System (MRAS). Several studies have been proposed in the literature concerning different approaches of MRAS estimators. In this work, an evaluation is performed of three MRAS approaches for estimate the rotor speed from different models: rotor flux, back electromotive force (back-EMF) and instantaneous reactive power. Matlab simulations are performed to test the proposed strategy for different speed and sensitivity of such drives to parameters variations. To verify the approach to sensorless techniques with variations of speed in real conditions a drive for the prototype was assembled and experimental results are presented.