Equivalent circuit parameters serve as the basis for performance estimation and implementation of power electronic drives controls and therefore their accurate evaluation is very important. Specified in the newly approved IEEE Std 1812, a short-circuit test can be employed, in combination with an open-circuit measurement, in order to determine the back emf and the synchronous inductance. In the case of interior permanent magnet (IPM) machines, this approach can be used only to determine the d-axis inductance and additional and separate measurements are required for the q-axis inductance. In this respect, various methods, inclusive of dc step response tests, on-load tests, and a widely used test in industry, which involves locked-rotor measurements at variable voltage and constant frequency supply, are studied in detail, based on two-dimensional finite element analysis. Locked-rotor methods based on dc current supply and static torque versus rotor position measurements are introduced for determining the q-axis inductance in combination with the standardized open-circuit and short-circuit tests. A critical study of the inductances determined from different tests is conducted, and experimental results on an IPM motor design with non-sinusoidal back emf, relatively high torque ripple, and low leakage are presented.

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Published in IEEE Transactions on Industry Applications, v. 55, issue: 3.

© 2019 IEEE Copyright Notice. “Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.”

The document available for download is the authors’ manuscript version that is accepted for publication. The final published version is copyrighted by IEEE and available as: V. Rallabandi, N. Taran, D. M. Ionel and P. Zhou, “Inductance Testing for IPM Synchronous Machines According to the New IEEE Std 1812 and Typical Laboratory Practices,” IEEE Transactions on Industry Applications, Vol. 55, no. 3, pp. 2649-2659, May-June 2019. doi: 10.1109/TIA.2019.2897668

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Funding Information

The support of University of Kentucky, the L. Stanley Pigman endowment and the SPARK program, and of ANSYS Inc. is gratefully acknowledged.