An adaptive sliding mode observer for induction machines

Control of induction machines in the so-called sensorless paradigm forms an interesting academic and practical problem. In this paper, an observer-controller system is proposed that can be used to control an induction machine with unknown parameters and partial state variable information. The observer is used to obtain the rotor flux linkage vector, needed for the sliding mode control based torque and flux control laws, while estimating speed and the unknown rotor resistance at the same time. In a nut shell, this system provides a unified sensorless control technique.