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Pulse width modulating motor controller

  • US 5,489,831 A
  • Filed: 09/16/1993
  • Issued: 02/06/1996
  • Est. Priority Date: 09/16/1993
  • Status: Expired due to Term
First Claim
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1. A pulse width modulation controller for an electric motor having a rotor, a stator, and a plurality of power phase (winding) circuits with each power phase circuit including a power switch, and means for producing a motor electrical (Me) signal which is a function of the revolutions per minute (RPM) of the rotor of the motor and its position relative to the stator of the motor;

  • comprising;

    circuit means responsive to the Me signal produced by the motor for producing a pulse width modulation signal;

    circuit means for producing power phase commutation signals the frequency of which has a fixed relationship to the frequency of said pulse width modulation signal, one power phase enable signal for each power phase winding circuit of the motor;

    circuit means for producing a speed error signal, said speed error signal being a function of the difference between the actual RPM of the rotor and a desired RPM; and

    pulse width modulation (PWM) circuit means for producing power drive signals for application to the power switch of each of the power phase winding circuits when each power switch is enabled by a power phase enable signal to receive said power drive signals, the frequency of the power drive signals produced by said PWM circuit means being that of the pulse width modulation signal, and the duty cycle of the power drive signals being a function of the speed error signal and of a power phase feedback signal produced by a power phase winding circuit when a power drive signal is applied to the power switch to energize said circuit, said power phase winding circuits being energized in sequence.

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