High-order terminal sliding-mode observer for speed estimation of induction motors

This paper proposes a high-order nonsingular terminal sliding-mode observer based sensorless field oriented control for induction motors. A nonsingular terminal sliding-mode manifold is designed for the observer and the related control strategies are applied to stabilize the whole motor system. The designed high-order sliding-mode control laws guarantee the strong robustness of the motor system and generate a smooth control signal which can be directly used for the estimation. The effect of the equivalent low-pass filter in the high-order sliding-mode mechanism can be regulated based on the performance requirements. In addition, the chattering phenomenon in the sliding-mode control based motor system can be eliminated effectively. The simulation results validate the proposed method.