A sliding mode observer for the induction motor

An observer is presented to estimate the magnetic flux components and speed of an induction motor based on stator voltage and current measurements alone. The observer is based on the principle of variable structure systems which immediately offers a number of advantages such as ensured stability, parameter insensitivity, noise rejection, etc. The principle of operation of a sliding mode observer is introduced in an intuitive manner using a simple first order system. Experimental results verifying the operation of the first order observer are presented. Then the sliding mode observer for the induction motor is discussed. Detailed simulation results verifying the operation under tuned and detuned conditions are presented. Practical realizations of the observer system based on robust implementation strategies are discussed