Estimating rotor parameters in induction motors using high-order sliding mode algorithms

A good estimate of the rotor´s parameters is essential in high-performance control of induction motors. It is shown that the structural impediment that prevents applying a usual adaptive observer to estimate these parameters is that the relative degree between the measured output and the unknown parameters is not one. Then, the high-order sliding mode differentiator is used to circumvent this restriction allowing the construction of a usual adaptive observer. Simulation results are presented to illustrate the performance of the proposed observer under ideal conditions and in the presence of measurement noises.