Determination of d and q reactances of permanent-magnet synchronous motors without measurements of the rotor position

• Published in: IEEE transactions on industry applications Vol. 36; no. 5; pp. 1330 - 1335
• Main Authors: Nee, H.-P., Lefevre, L., Thelin, P., Soulard, J.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-09-2000; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Area measurement; dq model; EMF; Flux; Induction motors; Industry Applications Society; Laboratories; Load tests; Mathematical analysis; Motors; permanent-magnet machine; Position measurement; power factor; Q measurement; Reactance; Rotors; Shafts; Studies; Synchronous motors; synchronous reactances; Testing
• ISSN: 0093-9994; 1939-9367; 1939-9367
• DOI: 10.1109/28.871281

The interest in permanent-magnet synchronous motors (PMSMs) is increasing in a wide area of applications. Since most PMSMs will operate without a shaft sensor in the future, valuable information for experimental determination of machine parameters will be lost. In this paper, therefore, a method is presented where the induced EMF and the d-axis reactance are determined in a no-load test and the q-axis reactance is determined in a load test. The load angle /spl delta/ is determined from the load test by means of a new analytical method. In this way, no separate measurement of the load angle is required. The method is especially suitable for line-start PMSMs which normally operate with negative d-axis current and, therefore, are not saturated in the d-axis flux paths. Moreover, the method is very simple to carry out for any laboratory technician, since the only tests that have to be made are standard tests which are made on standard induction motors on a regular basis.