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Axial gap permanent-magnet machine with reluctance poles and PM element covers

United States Patent

April 7, 2009
View the Complete Patent at the US Patent & Trademark Office
Oak Ridge National Laboratory - Visit the Partnerships Directorate Website
An electric machine (10) has a disk-shaped rotor (24) disposed in an operating space between two opposing stator assemblies (11, 12) to provide two axial air gaps (15, 16). The rotor (24) has a hub (28) and an outer ring (26) of non-magnetic material and is further provided with a plurality of permanent magnetic elements (25) for coupling flux that is induced by the magnetic field of the stator assemblies (11, 12). The permanent magnetic elements (25) are spaced apart and reluctance poles (27) are positioned in spaces between the magnetic elements (25) to couple additional flux induced by the magnetic field of the stator assemblies (11, 12). Various constructions and shapes (40-45) for the PM magnetic elements (25) are disclosed, and including PM covers (60) of ferromagnetic material for enhancing q-axis flux in the air gaps (15, 16) and for reducing harmonics where toothed stators are used. Methods of providing increased torque using the the various rotor constructions are also disclosed.
Hsu; John S. (Oak Ridge, TN), McKeever; John W. (Oak Ridge, TN)
UT-Battelle LLC (Oak Ridge, TN)
11/ 228,698
September 16, 2005
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH This invention was made with Government support under Contract No. DE-AC05-00OR22725 awarded to UT-Battelle, LLC, by the U.S. Department of Energy. The Government has certain rights in this invention.