A robust sliding mode observer for speed estimation of induction machine

In this paper, a new sliding mode flux and speed observer is proposed. The flux observer accuracy is guaranteed through the current observer. The error between the actual current and observed current converges to zero which guarantees the accuracy of the flux observer. The rotor speed is estimated by the observer based on the measured and estimated stator currents and estimated rotor flux. In addition, the command voltages are used rather then the measured ones. Therefore, in the proposed algorithm, only current sensors are needed. The new approach is verified by simulation and experimental results. The experimental results show the robustness and performance of the proposed observer structure