High-order Terminal Sliding Mode Flux Observer for Induction Motors

This paper proposes a rotor flux estimation method based on high-order sliding mode and non-singular terminal sliding mode for implementing the field orientation control of induction motors. A nonsingular terminal sliding mode and the control law of the observer are designed. The rotor flux of the motor is deduced using the designed control law. Meanwhile, the high-order sliding mode technique is adopted to eliminate the chattering phenomenon of the conventional sliding mode so that the control signal of the observer can be used directly for rotor flux estimation. Compared to conventional sliding mode observers, the proposed observer can estimate the system state with a higher precision. Further, it is insensitive to parameter variations. Simulation results validate the proposed method.