Flux estimation of induction motors using high-order terminal sliding-mode observer

This paper presents a rotor flux estimation method for induction motors based on high-order terminal sliding-mode observer. A terminal sliding mode manifold is designed for the observer and a control strategy is applied to stabilize the observer. A high-order sliding-mode mechanism is utilized in the observer controller to generate a smooth control signal, which can be directly used for the estimation of the rotor flux. The estimate of the rotor flux can be used for implementing the field orientation control of an induction motor. The effect of the equivalent low-pass filter in the high-order sliding-mode mechanism can be regulated according to the performance requirements.