A permanent magnet rotor containing an electrical winding to improve detection of motor angular position

Sensorless detection of rotor angular position is desirable for decreasing the cost and increasing the reliability of permanent magnet AC motor drive systems. This paper describes tests performed on a rotor that has surface mounted magnets and a conducting winding that links only the d-axis of the rotor. The conducting winding allows rotor angular position to be detected by stator-winding inductance variations.