Investigation of Servomotor Structure for Sensorless Control Based on High-Frequency Injection Method

Abstract

This paper presents the servomotor structure suitable for sensorless drives based on high-frequency injection method. The position estimation accuracy is related to the saliency ratio of the motor. Although the motor with increasing saliency ratio with the load has been reported, the mechanism of the phenomenon has not been explained.

In this paper, the improvement in the saliency ratio in a conventional servomotor structure is explained with respect to the magnetic flux distribution. Moreover, the increase in the saliency ratio through further structural improvement is examined, and the effect is confirmed by experiments.