Robust sliding mode control and flux observer for induction motor using two-time-scale approach

This paper presents a new method for designing robust adaptive sliding mode flux observer for induction motor drive. The idea is to combine singular perturbation and sliding mode techniques, obtaining in this way, the socalled two-time-scale sliding mode observer. The method assumes that the rotor speed signal is available. The control algorithm is based on the indirect field oriented sliding mode control with an on-line adaptation of the rotor resistance to keep the machine field oriented. The control-observer scheme seeks to provide asymptotic tracking of speed and rotor flux in spite of the presence of an uncertain load torque and unknown value of the rotor resistance. The validity for practical implementation has been verified through computer simulations.