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Artificial heart with sensorless motor

  • US 5,751,125 A
  • Filed: 11/08/1995
  • Issued: 05/12/1998
  • Est. Priority Date: 11/08/1995
  • Status: Expired due to Term
First Claim
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1. An artificial heart assembly having a sensorless, DC brushless motor, said artificial heart assembly comprising:

  • a blood inlet conduit;

    a blood outlet conduit;

    a pumping mechanism for pumping blood from said blood inlet conduit to said blood outlet conduit;

    a sensorless, DC brushless motor operatively connected to said pumping mechanism, said motor being reversibly driven in a first direction and a second direction, said motor changing between said first and second directions at a rate of at least 30 times per minute, said motor comprising;

    a permanent magnet rotor; and

    a stator rotatable relative to said permanent magnet rotor, said stator having a plurality of electrically energizable windings and a plurality of motor terminals to which said windings are electrically connected, wherein said rotor may be in Y possible angular position sectors with respect to said stator and wherein Y has a numeric value greater than two;

    means for periodically applying electrical signals to a plurality of said motor terminals while leaving at least one of said motor terminals unenergized to cause said rotor to rotate alternately in said first direction and second directions, said rotor changing between said first and second directions at a rate of at least about 30 times per minute;

    means for detecting a voltage at said unenergized motor terminal; and

    means for determining, based upon said voltage detected by said detecting means, that said rotor is in one of X possible angular position sectors, where X has a numeric value less than said numeric value of Y.

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