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METHOD FOR DETECTING DETERIORATION OF PERMANENT MAGNET IN ELECTRIC MOTOR AND SYSTEM FOR THE METHOD

  • US 20120187878A1
  • Filed: 01/19/2012
  • Published: 07/26/2012
  • Est. Priority Date: 01/20/2011
  • Status: Abandoned Application
First Claim
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1. A method for detecting deterioration of a permanent magnet in an electric motor, the electric motor having multi-phase coils and a rotor that incorporates the permanent magnet, the method comprising:

  • a first peak current measuring step of applying a first pulsed voltage to the multi-phase coils so as to generate magnetic flux directed in the same direction as the magnetic flux generated by the permanent magnet and measuring a first peak current when the electric motor is started;

    a second peak current measuring step of applying a second pulsed voltage to the multi-phase coils so as to generate magnetic flux directed in the direction opposite to the direction in which magnetic flux is generated by the permanent magnet and measuring a second peak current when the electric motor is started; and

    a determination step of determining whether or not the permanent magnet is deteriorated based on the difference of the absolute value between the first peak current and the second peak current.

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