Comparison of two nonlinear speed observers for induction motors

In this paper, the performances of two rotor flux and speed estimation methods used in speed sensorless vector controllers of induction motors are compared. Both Kalman filter (KF) and model reference adaptive system (MRAS) are the estimation methods discussed and compared at the same conditions. The comparative study is done by means of stability, sensitivity to parameter variation and behavior in the low speed region taking into account the drawbacks inherent to this operating condition. Computer simulations and experimental tests have been carried out in identical conditions in order to realize a reliable comparison