Speed estimation technique for PMSM with initial rotor position uncertainty

This paper describes a new sensorless speed and position estimation technique for Permanent Magnet Synchronous Motor (PMSM). It is based on a stator flux/current observer connected with a modified back Electromotive Force (EMF) observer. The objective is to design an accurate estimator according to some specifications, as the ability to cancel any stator resistance changes and initial rotor position error. This first property is realized by using an improved resistance observer in the estimation procedure. Any initial rotor position uncertainty could be compensated by means of the back EMF observer. The robustness of the estimation algorithm toward noise and parameters variation of the PMSM is validated by simulation experiments performed on a salient-pole PMSM.