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Method of controlling an automatic door system

  • US 8,405,337 B2
  • Filed: 11/11/2009
  • Issued: 03/26/2013
  • Est. Priority Date: 11/12/2008
  • Status: Active Grant
First Claim
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1. A method for controlling an electric motor of an automatic door system, the motor comprising a brushless DC motor being operatively connected to a door panel to enable the motor to perform a door moving operation for moving the door relative to a door frame, the motor being operable to move the door between open and closed positions using electric power signals delivered to the motor from an electric power supply, the electric power signals being controlled through a motor controller in communication with a system controller, and the system controller being operable to provide control signals to the motor controller for switching power source connections from the power supply to windings of the motor to define motor actuation operations, the method comprising:

  • at the system controller selecting a motor actuation operation from a plurality of predetermined motor actuation operations, and providing control signals to the motor controller corresponding to the selected motor actuation operation, wherein the motor controller comprises an inverter circuit controlling the power source connections to the windings of the brushless DC motor;

    effecting control of movement of the door using the selected motor actuation operation whereby the angular position of the door relative to the door frame is controlled by switching the power source connections in response to the control signals received from the system controller; and

    wherein the motor actuation operation comprises switching the power source connections in the inverter circuit to short together a plurality of the motor windings to produce a braking torque in the motor in accordance with a pulse width modulation control to maintain the door at a substantially stationary position relative to the door frame including providing a resistance to an external force applied on the door in a door opening direction wherein the pulse width modulation control is performed at a selected duty cycle without providing a motive electrical power to the motor.

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