A sensorless initial rotor position estimation scheme for a direct torque controlled interior permanent magnet synchronous motor drive

This paper presents a method of determining the initial rotor position of an Interior Permanent Magnet Synchronous Motor (IPMSM) which is required for Direct Torque controlled (DTC) IPMSM drives. The method consists of injecting a high frequency voltage to the windings and examining the effects of the saliency on the amplitude of the corresponding stator current components. This method does not depend on the level of static load and on any motor parameters. Also the magnetic pole is identified utilizing the effect of magnetic saliency.