Mirror-phase characteristics of high-frequency current in AC motors with pole-saliency and position estimation methods for sensorless vector controls

Ths paper newly analyzes the minor-phase characteristics of AC motors with pole-saliency such as interior permanent magnet synchronous motor (IPMSM), and also shows that the characteristics are inherent to the motors, and it can be utilized for rotor position estimation with no mechanical position sensor such as an encoder. As a concrete application of a newly presented rotor position estimation, this paper also proposes a novel sensorless vector control method for IPMSM, which is insensitive to motor parameters and can operate from zero to rated speed under the rated load. Usefulness of the sensorless vector control is confirmed through experiments.