Elevator drive control during power disruption

Patent metadata

Field	Value
Publication number	US-2019202663-A1
Application number	US-201716303221-A
Country	US
Kind code	A1
Filing date	May 31, 2017
Priority date	May 31, 2016
Publication date	Jul 4, 2019
Grant date	—

Abstract

A drive control method and system for controlling an inverter during power disruptions in the operation of an elevator drive includes the steps of predetermining whether a hoist motor of the elevator drive will be operating in a motor mode, a balanced mode or a regenerative mode on commencement of the power disruption, and controlling the inverter in accordance with the predetermined operating mode after commencement of the power disruption.

First claim

1 - 15 . (canceled)

16 . A method of operating an elevator drive to move an elevator car during a disruption of a mains power supply independently of any alternative energy storage for feeding power to the drive, comprising the steps of:
predetermining, by sampling a current delivered between a hoist motor and an inverter of the drive, whether the hoist motor will be operating in a balanced mode, in which balanced mode a magnitude of the sampled current is less than a predetermined current threshold, or in a motor mode or a regenerative mode, in which motor and regenerative modes the magnitude of the sampled current is greater than the predetermined current threshold, on commencement of the power disruption; and controlling the inverter in accordance with the predetermined hoist motor operating mode independently of the alternative energy storage after the commencement of the power disruption.

17 . The method according to claim 16 wherein the sampling of the current is performed at a beginning of an elevator trip of the elevator car as an associated elevator brake is opened and the drive is providing the current to keep the motor stationary.

18 . The method according to claim 16 wherein the sampling of the current is performed during a constant speed phase of an elevator trip of the elevator car.

19 . The method according to claim 16 wherein the motor is predetermined to be in the motor mode or the regenerative mode depending on a direction of travel of the elevator car.

20 . The method according to claim 16 including a step of changing the inverter to a regenerative switching schedule if the hoist motor is in the balanced mode after the commencement of the power disruption.

21 . The method according to claim 16 including a step of switching off the inverter if the hoist motor is in the motor mode after the commencement of the power disruption.

22 . The method according to claim 16 wherein:
the operating mode of the hoist motor is predetermined by sampling the current at a beginning of an elevator trip of the elevator car as an associated brake is opened and the drive provides the current to keep the motor stationary, or by sampling the current during a constant speed phase of the elevator trip of the elevator car; and
switching off the inverter after the commencement of the power disruption if the hoist motor is in the motor mode, or changing the inverter to a regenerative switching schedule after commencement of the power disruption if the hoist motor is in the balanced mode.

23 . A system for operating an elevator hoist motor to move an elevator car during a power disruption comprising:
an energy storage connectable to an elevator brake for the elevator car; and a drive delivering power from an AC power supply to an elevator hoist motor, wherein the drive comprises
a converter for converting AC power from the power supply into DC power,
an inverter for driving the hoist motor by inverting the DC power from the converter into AC power and for rectifying AC power produced by the hoist motor when the hoist motor is in a generating mode into DC power,
a DC link connected between the converter and the inverter and being independent from the energy storage, and
a controller for controlling operation of the drive, wherein the controller samples a current transferred between the inverter and the hoist motor during a trip of the elevator car to determine whether the hoist motor is operating in a motor mode, a balanced mode or a regenerative mode, and after commencement of a power disruption controls the inverter in accordance with the determined operating mode.

24 . The system according to claim 23 wherein the controller keeps the brake connected to the energy storage on the commencement of the power disruption.

25 . The system according to claim 23 wherein the controller switches off the inverter after the commencement of the power failure if the hoist motor is in the motor mode.

26 . The system according to claim 23 wherein the controller changes the inverter to a regenerative switching schedule after the commencement of the power failure if the hoist motor is in the balanced mode.

27 . The system according to claim 23 wherein after the commencement of the power disruption the controller switches off the inverter if the hoist motor is in the motor mode or changes the inverter to a regenerative switching schedule if the hoist motor is in the balanced mode.

Assignees

• Inventio Ag

Inventors

• Camenzind Roman
• Eilinger Thomas
• Prakash Om

Classifications

• B66B5/027 Primary

  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 title

• B66B1/3407

  Setting or modification of parameters of the control system · CPC title

• B66B1/308

  with AC powered elevator drive · CPC title

• B66B5/02 Primary

  responsive to abnormal operating conditions · CPC title