Sensorless controls of salient‐pole permanent magnet synchronous motors using extended electromotive force models

In this paper, we propose a new mathematical model for synchronous motors and a sensorless control method based on it. To control permanent magnet synchronous motors, knowledge of rotor position and velocity are necessary. Heretofore, expensive sensors have been used to detect rotor position information. Although many sensorless control methods based on the electromotive force (EMF) have been developed for non-salient-pole permanent magnet motors, they cannot be applied for salient-pole motors without approximation because of complications in the mathematical model; this is turn may lead to problems of instability. To solve this problem, we propose an extended electromotive force model for synchronous motors. The proposed model has a simple structure, making position estimation possible without approximation. Experimental results show that the proposed model and method are valid. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(3): 55–64, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10257