Trends in Motor Drive Techniques in Japan

—Controls for Synchronous Motors with Non-linearity—

Abstract

This paper surveys some notable efforts on improvement of position sensorless control of interior permanent magnet synchronous motors and synchronous reluctance motors. These motors are widely utilized for saving energy and for their high power density, and the control techniques for these motors have advanced to address recent trends in motor development. This paper focuses particularly on the position estimation and current control techniques developed in Japan for motors with considerable magnetic non-linearity and demonstrates solutions that have been proposed for improvements in the performance of position sensorless control.