Sliding-mode control of an induction motor without flux measurement

A new approach to control the speed and rotor flux of an induction motor using the theory of the sliding-mode is presented. Sabanovic's equations for an induction motor are first modified to a state space form suitable for the present design of the algorithm. For controlling the speed and rotor flux of the drive, a simple control algorithm is proposed based on the existence of a certain positive definite matrix. The Lyapunov direct method is used to ensure the reaching and sustaining of sliding-mode. Obviation of flux measurement is achieved through manipulation of Stanley's equations. Simulation studies are conducted. The control algorithm exhibits excellent drive performance in the presence of load disturbances and stator and rotor resistances changes up to 100% of the nominal values.<
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