Adaptive observer for speed sensorless PM motor control

This paper presents an adaptive observer for extimating the rotor position and speed of a permanent magnet synchronous motors (PMSM). The observer compensates for voltage offsets and permanent magnet strength variations. The adaptation structure for estimating the strength of the permanent magnet is determined from a Lyapunov stability proof. The observer estimates the stator flux by integration of the measured BEMF signal. In order to verify the applicability of the method the observer has been implemented and tested on a 800 W motor