Sensorless-Oriented Design of PM Motors

This paper deals with the design of a permanent-magnet (PM) motor for zero-speed sensorless rotor position detection, by means of injection of a high-frequency signal. Various aspects are investigated: influence of the rotor structure, stator and rotor saturation, reliability of finite-element analysis to predict the motor performance, and influence of rotor iron bridges and of rotor eddy currents induced. The results presented in this paper give the key rules to designing a PM motor suitable for sensorless rotor position detection.