Extended EMF Models of Synchronous Reluctance Motors and Selection of Main Flux Direction

Abstract

A new mathematical model called an Extended EMF (EEMF) model and a sensorless control method using the concept for PMSMs have proposed by authors, and their availability have been verified by experiments. The purpose of this paper is to apply the EEMF model to sensorless control of synchronous reluctance motors. Since synchronous reluctance motors do not have any permanent magnet, a main flux direction of a motor model can be chosen in two ways. And the difference of the main flux direction leads to two EEMF models. Between two EEMF models, there is some difference from the point of the motor model for sensorless control. We indicate the difference of two EEMF models clearly and derive the difference of the position estimation error caused by deviation of inductance parameters. Moreover, the selection way of EEMF models is discussed. Finally, the selection method is verified by experiments.