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Title: Torque ripple reduction in electric machines

An electric machine, such as an Internal Permanent magnet or Synchronous Reluctance machine, having X phases, that includes a stator assembly, having M slots, with a stator core and stator teeth, that is further configured with stator windings to generate a stator magnetic field when excited with alternating currents and extends along a longitudinal axis with an inner surface that defines a cavity; and a rotor assembly, having N poles, disposed within the cavity which is configured to rotate about the longitudinal axis, wherein the rotor assembly includes a shaft, a rotor core located circumferentially around the shaft. The machine is configured such that a value k=M/(X*N) wherein k is a non-integer greater than about 1.3. The electric machine may alternatively, or additionally, include a non-uniformed gap between the exterior surface of the rotor spokes and the interior stator surface of the stator.
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Issue Date:
OSTI Identifier:
Patent Number(s):
Application Number:
Contract Number:
Resource Relation:
Patent File Date: 2013 Oct 18
Research Org:
GENERAL ELECTRIC COMPANY, Niskayuna, NY) (United States)
Sponsoring Org:
Country of Publication:
United States

Other works cited in this record:

Synchronous reluctance electrical motor having a low torque-ripple design
patent, October 1998

Method and apparatus for torque ripple reduction in sinusoidally excited brushless permanent magnet motors
patent, April 2002

Rotor having multiple permanent-magnet pieces in a cavity
patent, March 2009

Electric machine
patent, March 2011

Cooling system for rotating machine
patent, August 2011

Dovetail spoke internal permanent magnet machine
patent, August 2011

Induction motor lamination design
patent, April 2012

Rotating electric machine having rotor embedded-permanent-magnets with inner-end magnetic gaps and outer-end magnetic gaps, and electric car using the same electric machine
patent, March 2013

Permanent magnet electric machine and permanent magnet with linearly increasing air gap for an electric machine
patent, April 2013

Interior permanent magnet synchronous motor
patent-application, April 2002

Permanent Magnet Embedment Rotating Electric Machine, Motor for Car Air Conditioner, and Enclosed Electric Compressor
patent-application, November 2007

Permanent-Magnet Reluctance Electrical Rotary Machine
patent-application, April 2008

Permanent Magnet Rotating Electric Machine and Electric Car Using the Same
patent-application, July 2009

Induction Motor with Improved Torque Density
patent, June 2010

Dovetail Spoke Internal Permanent Magnet Machine
patent-application, November 2010

Fractional Slot Multiphase Machines with Open Slots for Simplified Conductor Insertion in a Stator
patent-application, January 2011

Rotating Electrical Machine
patent-application, June 2011

Torque Ripple Reduction in Interior Permanent Magnet Synchronous Machines Using Stators With Odd Number of Slots Per Pole Pair
journal, March 2010
  • Han, Seok-Hee; Jahns, Thomas M.; Soong, Wen L.
  • IEEE Transactions on Energy Conversion, Vol. 25, Issue 1, p. 118-127
  • DOI: 10.1109/TEC.2009.2033196

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