This paper proposes different configurations of axial-field machines featuring a very large ratio of the number of rotor poles to stator teeth and coils suitable for low-speed direct-drive traction applications. The machines have a single rotor with spoke-type permanent magnets and the stator teeth include auxiliary slots, the function of which is to enhance the high-polarity component of the stator magnetomotive force interacting with the rotor to produce a net torque. The machines can be constructed with three or two phases, in which case they inherently exhibit high tolerance to faults due to the combined effect of a lack of coupling between phases and a relatively large phase inductance. A preliminary comparative simulation study shows performance improvement over a conventional reference permanent magnet synchronous machine.
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The support of National Science Foundation NSF Grant #1809876, of University of Kentucky, the L. Stanley Pigman endowment and of ANSYS, Inc. is gratefully acknowledged.The authors would also like to thank Professor Ion G. Boldea from University of Politehnica of Timisoara, Timisoara, Romania, for valuable suggestions and discussions.
Rallabandi, Vandana; Han, Peng; Kesgin, Murat G.; Taran, Narges; and Ionel, Dan M., "Axial-Field Vernier-Type Flux Modulation Machines for Low-Speed Direct-Drive Applications" (2019). Power and Energy Institute of Kentucky Faculty Publications. 15.