High speed sensorless fuzzy-like Luenberger observer

This paper presents a new method based on the Luenberger observer to estimate the flux and the speed of an induction motor. The method uses different values of the discrete observer matrix computed offline at different speeds in order to keep the poles inside the stability region. As the motor speed changes, the proper observer matrix is selected by the control system: in this way, the dynamic response and the stability of the observer are guaranteed at high speed as well as at low speed. The performance of a 4-pole induction motor drive, using the proposed observer, has been tested. Experimental results are shown up to 12,000 RPM.