Performance comparison of Rotor Flux based and Back EMF Based Model Reference Adaptive System Speed Estimator for 3 Phase Induction Motor

Sensorless speed control of an induction motor is a popular method used in vector control or v/f control of industrial drives. Using induction motor dynamic equations mathematical models are developed for speed estimation. One limitation of model-based speed estimator is the accuracy of estimator changes with changes in IM winding temperature. The effect of a change in stator winding resistance is analyzed for RFB and BEB Model Reference Adaptive System (MRAS) speed estimators for induction motors. Both approaches’ control laws are derived from the induction motor’s dynamic equation. The investigation of the speed estimator’s performance for fluctuations in the stator resistance parameter at both high and low speeds is illustrated using MATLAB simulation. This analysis helps to know the change in MRAS speed estimators’ output transient response and steady-state error due to changes in stator resistance.