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Electric motor phase control system

  • US 9,130,494 B2
  • Filed: 09/26/2013
  • Issued: 09/08/2015
  • Est. Priority Date: 09/26/2013
  • Status: Active Grant
First Claim
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1. An apparatus comprising:

  • a controller configured toidentify a start time for a signal based on a back electromotive force present in an electric motor during operation of the electric motor, wherein the start time is for a position of a rotor relative to a group of coils; and

    send the signal to the group of coils using the start time identified, wherein an effect of the back electromotive force on the signal is reduced;

    wherein the signal is a current in the electric motor and has a waveform and the controller is configured toidentify a first area under the waveform,identify a second area under a commanded waveform resulting from a commanded current for the electric motor, andchange the start time based on a difference between the first area and the second area; and

    wherein the controller is configured to advance the start time to an earlier start time if the first area is less than the second area by a selected amount.

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