Design of a MRAS, Speed and Flux Estimators used in Sensorless Control of Induction Motors

Abstract

Model reference adaptive system (MRAS) based

techniques are one of the best methods to estimate the rotor

speed. Speed and torque control of an induction motor is usually

attained by application of a speed or position sensor. However,

these require the additional mounting space, reduce the

reliability and increase the cost of the motor. The recent trend in

field oriented control (FOC) is towards the use of sensorless

techniques that avert the use of speed sensor and flux sensor.

This paper seeks to provide a direct comparison between two

technics of induction motor MRAS based speed estimators, one

based on the rotor flux and the other based on the back EMF.

Comparison between the two techniques is made through

computer simulations.

Keywords

• Induction motor drive,adaptive observer,MRAS,stability analysis

References

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