Axial flux permanent magnet (AFPM) synchronous motors are attractive for low speed direct drive systems because of their high specific torque. The present paper proposes a novel axial flux machine topology, called MAGNUS, obtained by combining a yokeless central stator type NS arrangement with two external high polarity spoke-rotors, resulting in very high flux concentration. The stator, which includes main and auxiliary teeth for air-gap profiling has a small number of concentrated coils. Two stator configurations are discussed, the first, a yokeless construction with coils wound around the teeth, and the second with coils placed around the stator core in a Gramme ring arrangement. Feasible slot pole combinations are identified. High torque densities are achievable owing to torque magnification achieved by air-gap profiling as well as flux concentration. Initial analysis indicates that this machine presents higher torque than a YASA machine, which currently holds a record for torque density.

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Conference Proceeding

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Notes/Citation Information

Published in 2017 IEEE Energy Conversion Congress and Exposition (ECCE).

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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: V. Rallabandi, N. Taran, D. M. Ionel and I. G. Boldea, “MAGNUS – An ultra-highspecific torque PM axial flux type motor with flux focusing and modulation,” Rec. 2017 IEEE Energy Conversion Congress and Exposition (ECCE), Cincinnati, OH, 2017, pp.1234-1239. doi: 10.1109/ECCE.2017.8095930

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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.