The paper presents a study of the torque production in a novel vernier-type axial-flux permanent magnet (PM) machine topology named MAGNUS. Two computational methods are employed, one based on the 3D FEA Maxwell stress calculations on individual stator and rotor components and one based on the analytical derivation of the air-gap flux density harmonics. Examples are provided for a design with a 40-pole spoke-type PM rotor and two stators, one active including a 3-phase winding with 6 concentrated coils wound around main teeth in a single layer arrangement and a second stator that has neither coils nor main slots and is profiled towards the airgap in the same way as the active stator. It is shown that auxiliary small teeth included in the stator main teeth yield a significant increase in the output torque and that the profiled stator has a lower contribution than the active stator to the total torque. A brief report on the ongoing development of a prototype motor is included.

Document Type

Conference Proceeding

Publication Date


Notes/Citation Information

Published in 2021 IEEE International Electric Machines & Drives Conference.

© 2021 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 accepted for publication. The final published version is copyrighted by IEEE and will be available as: M. G. Kesgin, P. Han, D. Lawhorn, and D. M. Ionel, “Analysis of Torque Production in Axial-flux Vernier PM Machines of the MAGNUS Type,” 2021 IEEE International Electric Machines and Drives Conference (IEMDC), Hartford, CT, May. 16-19, 2021.

Digital Object Identifier (DOI)


Funding Information

This material is based upon work supported by the National Science Foundation (NSF) under Grant No. 1809876. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the NSF. The support of University of Kentucky, the L. Stanley Pigman Endowment, and of ANSYS, Inc. is also gratefully acknowledged.