Apparatus for controlling rescue operations and for improving power efficiency

• US 5,864,474 A
• Filed: 04/09/1998
• Issued: 01/26/1999
• Est. Priority Date: 04/10/1997
• Status: Expired due to Fees

• Current Assignee: LG Otis Elevator Company
• Original Assignee: LG Industrial Systems Co., Ltd (LG Corporation)
• Inventors: Jang, Cheol Ho
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Han, Y. J.
• Application Number:
  US09/057,459
• Time in Patent Office: 292 Days
• Field of Search: 363/37, 363/39, 363/40, 363/50, 363/55, 363/56, 307/64, 307/65, 307/66, 187/290, 187/296, 187/297
• US Class Current: 363/39
• CPC Class Codes: B66B 5/027 to permit passengers to leave an elevator car in case of failure, e.g. moving the car to a reference floor or unlocking the door
• CPC Class Codes: H02J 3/1842 wherein at least one reactive element is actively controlled by a bridge converter, e.g. active filters
• CPC Class Codes: H02J 3/32 using batteries with converting means
• CPC Class Codes: Y02E 40/20 Active power filtering [APF]

Abstract

An apparatus for controlling rescue operations and for improving power efficiency in which an Auto Landing of Power failure ALP device is provided with an active power filter for supplying a compensation current to a control unit when the ALP device is in a stand by condition that a power failure does not occur. The apparatus includes a control unit for controlling an operation of an elevator cage by activating an induction motor with a three-phase AC voltage source; an ALP device for controlling an emergency mode by supplying the three-phase AC voltage converted from a DC voltage from a battery by a stand-by inverter when a power failure occurs, opening/closing contacts being opened in a normal power supply condition so as to make the ALP device not connected to the control unit and being closed in a power failure condition so as to make the ALP device connected to the control unit for supplying the power; a DC voltage detector for detecting the DC voltage supplied to the stand-by inverter; a real current detector for detecting the current supplied to the control unit in the normal power supply condition; a power source voltage detector for detecting a voltage of the power source supplied to the control unit; and an automatic rescue operation controller for controlling the ALP device to perform an automatic rescue operation in the power failure condition, and for acting as an active power compensation filter in the normal power supply condition.

Claims

1. An apparatus for controlling a rescue operation and for improving a power efficiency, having a control unit for controlling an operation of an elevator by activating an induction motor with a three-phase AC voltage source, and an ALP (Auto Landing of Power failure) device for controlling an emergency mode by supplying the three-phase AC voltage converted from a DC voltage from a battery by means of a stand-by inverter when a power failure occurs, the apparatus comprising:

opening/closing contacts being opened (OFF) in a normal power supply condition so as to make the ALP device not connected to the control unit and being closed (ON) in a power failure condition so as to make the ALP device connected to the control unit for supplying the power;

a DC voltage detector for detecting the DC voltage supplied to the stand-by inverter;

a load current detector for detecting the current supplied to the control unit in the normal power supply condition;

a power source voltage detector for detecting a voltage of the power source supplied to the control unit; and

an automatic rescue operation controller for controlling the ALP device to perform an automatic rescue operation in the power failure condition determined in accordance with output signals of the DC voltage detector, and for acting as an active power compensation filter in the normal power supply condition determined in accordance with output signals of the load current detector, the DC voltage detector, and the power source voltage detector.

2. The apparatus as defined in claim 1, wherein the automatic rescue operation controller comprises:

a mode control unit for setting an operation mode of the ALP device either with an ALP operation mode in the power failure condition or with an active filter mode in the normal power supply condition after either the power failure condition or the normal power supply condition is determined in accordance with the output signal of the DC voltage detector; and

an imaginary current calculating section for calculating an effective current upon receipt of a load current from the load current detector, a DC voltage from the DC voltage detector, and a power source voltage from the power source voltage detector, and for calculating a compensation current by adding or subtracting the load current to or from the effective current so as to provide a compensation current control value to the stand-by inverter.

3. The control apparatus as defined in claim 2, wherein the imaginary current calculating section calculates the effective current from the load current passing through the control unit, adds the DC value to the effective current so as to get a total effective current, multiplies the total effective current by the power source voltage detected by the voltage detector, and then adds or subtracts the load current to or from a multiplied value so as to get the compensation current for compensating for the imaginary current.