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Direct control of air gap flux in permanent magnet machines

United States Patent

May 2, 2000
View the Complete Patent at the US Patent & Trademark Office
Oak Ridge National Laboratory - Visit the Partnerships Directorate Website
A method and apparatus for field weakening in PM machines uses field weakening coils (35, 44, 45, 71, 72) to produce flux in one or more stators (34, 49, 63, 64), including a flux which counters flux normally produced in air gaps between the stator(s) (34, 49, 63, 64) and the rotor (20, 21, 41, 61) which carries the PM poles. Several modes of operation are introduced depending on the magnitude and polarity of current in the field weakening coils (35, 44, 45, 71, 72). The invention is particularly useful for, but not limited to, the electric vehicle drives and PM generators.
Hsu; John S. (Oak Ridge, TN)
Lockhead Martin Energy Research Corporation (Oak Ridge, TN)
09/ 234,919
January 21, 1999
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH This invention was made with Government support under Contract No. DE-AC05-960R22464 awarded by the U.S. Department of Energy. The Government has certain rights in the invention.