States observer design for slip mode control of three-phase induction motor

The sensorless slip mode control of the Induction machine offers the possibility to achieve high performance in both transient and steady-state operation. This depends on the one hand on the estimation of the flux value in the machine, and on the other hand on the estimation of the speed to eliminate the disadvantages of mechanical sensors. The main idea of this paper is the implementation of a non-linear observer to preserve the high performance of this control, to estimate the speed, in order to realize a control without mechanical speed sensor which has many advantages. These advantages are: the elimination of the sensor and the sound cable, the reduction of noise, the increase of the reliability of the electric drive, as well as the reduction of its complexity and cost.