In traditional electric machines, it is usually possible to achieve constant power high-speed operation by employing field weakening through the injection of a negative d-axis current component. However, in machines with low armature inductance, such as high power density permanent magnet synchronous machines, and more specifically, coreless machines, which are gaining increasing attention because of their high specific torque, the extended speed range obtained using this method is very narrow. This paper summarizes the performance characteristics of existing approaches for obtaining constant power operation and proposes two new techniques, specially applicable to coreless axial flux permanent magnet machine namely, current weakening and relative winding rotation.

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Conference Proceeding

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Published in 2018 IEEE Transportation Electrification Conference and Expo (ITEC).

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The document available for download is the authors’ manuscript version that is accepted for publication. The final published version is copyrighted by IEEE and will be available as: D. Lawhorn, N. Taran, V. Rallabandi, and D. M. Ionel, “A comparative study ofconstant power operation techniques for low inductance machines,” 2018 IEEE Transportation Electrification Conference and Expo (ITEC), Long Beach, CA, 2018, pp. 638-643. doi: 10.1109/ITEC.2018.8450184

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Funding Information

The support of the NASA Kentucky Space Grant Consortium, University of Kentucky, the L. Stanley Pigman endowment, and ANSYS, Inc. are gratefully acknowledged.