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Apparatus and method for controlling emergency operation in elevator system

  • US 5,945,644 A
  • Filed: 11/03/1997
  • Issued: 08/31/1999
  • Est. Priority Date: 11/04/1996
  • Status: Expired due to Term
First Claim
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1. An apparatus for controlling an emergency operation in an elevator system, comprising:

  • an inverter for inverting a direct voltage into alternating voltages and driving an induction motor with the alternating voltages;

    a current detector for detecting current that flows through the induction motor;

    a speed detector for detecting a speed of the induction motor and outputting phase signals; and

    a control circuit for receiving the current outputted from the current detector and the phase signals outputted from the speed detector, and outputting a voltage command to the inverter, the control circuit including,a speed detection unit for receiving the phase signals outputted from the speed detector, and calculating an angular velocity of the induction motor;

    a driving direction setting unit for receiving the phase signals outputted from the speed detector and the angular velocity from the speed detection unit, and determining a driving direction of an elevator car;

    a speed command generator for receiving an output signal from the driving direction setting unit, and outputting a speed command;

    a first subtractor for outputting a difference value between the speed command and the angular velocity;

    a speed controller for amplifying the difference value outputted from the first subtractor, and outputting a current command for the induction motor;

    a second subtractor for outputting a difference value between the current command and the current outputted from the current detector; and

    a current controller for amplifying the difference value outputted from the second subtractor, and outputting the voltage command to the inverter.

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