An adaptive sliding observer for sensorless control of synchronous motors

An adaptive sliding observer is proposed for position and velocity sensorless control of synchronous motors. Unlike conventional sensorless control methods, which are only applicable for one or two types of synchronous motors, the proposed method is a universal sensorless control for all the three types of synchronous motors. This is because it is based on the newly derived extended electromotive force model, which fuses position information both from the permanent magnet and from the stator inductance. Stability of the proposed observer is guaranteed easily, because it is constructed on a linear model. of the motor. Sliding mode is applied for the current estimation, under which the order of observer's error equation is reduced. This makes the stability analysis easier so that robust position and velocity estimations might be achieved by a proper pole assignment. Simulation results show that the proposed method is very effective.