Sensorless Sliding Mode Observer based on rotor position error for salient-pole PMSM

This paper introduces a new simple sensorless algorithm of estimating the permanent magnet synchronous motor (PMSM) speed and position. The proposed estimation method is implemented using a stator flux/current and a modified back electromotive force (EMF) observer connected in cascade. The flux/current observer based on sliding mode techniques ensures stator currents convergence while the modified back EMF observer provides accurate rotor position estimation at a wide range of motor speeds. An adaptive stator resistance observer is embedded in the flux/current sliding mode observer (SMO) and improves the overall observation system convergence. Simulation results show good properties of the proposed estimation approach.