Analysis of permanent-magnet machine for sensorless control based on high-frequency signal injection

Sensorless control of surface-mounted permanent-magnet (SMPM) machine is still a challenge. This paper presents the analysis of a SMPM machine for the sensorless control scheme based on high-frequency rotating voltage signal injection method. The method enables to track even the small saliencies typical for SMPM machine. In order to support this, the high-frequency inductances of a SMPM machine are analyzed by finite-element analysis (FEA) method. A rotating high-frequency model of a SMPM machine is developed and a sensorless rotor position and speed estimation algorithm is described. A commercial SMPM machine was used to do the experiments, and the speed and position estimation results are presented.