Patent ID: 8531143
Filing Date: 2013-09-10
Classification: H02K,H02P

Abstract:
1. A permanent magnet motor system comprising: a rotor supported to rotate about an axis and holding at least one permanent magnet providing multiple angularly spaced magnetic poles; a stator fitting about the rotor so that the rotor may rotate within and with respect to the stator, the stator providing a plurality of angularly spaced teeth extending inward toward the rotor; electrically conductive coils coiling around at least some of the teeth to apply a magnetic field thereto; an injection signal generator applying an electrical signal to the at least one coil at a frequency substantially higher than a drive frequency applied to the coils, the latter to cause rotation of the rotor; and an injection signal analyzer analyzing the injection signal to detect variations in the inductance of the at least one coil functionally related to the rotor position to deduce rotor position; wherein the angularly spaced teeth are shaped so that the inductance at a q-phase of the rotor is lower than the inductance at a d-phase of the rotor.