Automatic rescue and charging system for elevator drive

Patent metadata

Field	Value
Publication number	US-11053096-B2
Application number	US-201715688288-A
Country	US
Kind code	B2
Filing date	Aug 28, 2017
Priority date	Aug 28, 2017
Publication date	Jul 6, 2021
Grant date	Jul 6, 2021

Abstract

A method and system for providing power to an elevator hoist motor is disclosed. An isolated bi-directional dc/dc converter is coupled between a power converter and a power inverter. A battery is coupled to the isolated bi-directional dc/dc converter. A processor is configured to sense power levels and couple the battery to an elevator hoist motor via the isolated bi-directional dc/dc converter depending on the voltage of the main power supply. The isolated bi-directional dc/dc converter is also configured to provide power to charge the battery.

First claim

What is claimed is:

1. A method of driving an elevator car comprising:
converting alternating current from a main power supply to direct current at a power converter;
converting direct current at the power converter to alternating current at a power inverter;
powering a hoist motor coupled to the power inverter configured to have a regenerative mode;
connecting an isolated bi-directional dc/dc converter between the power converter and the power inverter;
monitoring a voltage level of the main power supply; and
based on a determination that the voltage level of the main power supply is below a first predetermined threshold, directing the isolated bi-directional dc/dc converter to boost a voltage input from a battery to a level sufficient to drive the elevator car in a rescue mode, wherein the rescue mode drives the elevator at a low speed in a direction assisted by gravity;
monitoring a voltage level of the battery; and
based on a determination that the voltage level of the battery is below a second predetermined threshold and a determination that the voltage level of the main power supply is above the first predetermined threshold, charging the battery via the isolated bi-directional dc/dc converter.

2. The method of claim 1 wherein the level sufficient to drive the elevator car in the rescue mode ranges from approximately 70 to 300 volts.

3. The method of claim 1 further comprising:
monitoring a temperature of the battery; wherein:
charging the battery comprises:
determining an optimum charging cycle for the battery using the voltage level of the battery and the temperature of the battery; and
applying the optimum charging cycle to the battery.

4. The method of claim 1 wherein:
charging the battery comprises using power from the main power supply to charge the battery.

5. The method of claim 1 wherein:
charging the battery comprises using power from an elevator hoist motor operating in a regenerative mode to charge the battery.

6. The method of claim 1 wherein:
the isolated bi-directional dc/dc converter is configured to receive a line voltage as input and output a voltage optimal to charge the battery.

7. The method of claim 6 wherein the battery is a 48 volt battery and the voltage optimal to charge the battery is in the range of 50 to 55 volts.

8. The method of claim 6 wherein the line voltage is approximately 380 to 480 volts.

9. An elevator power system comprising:
an input coupled to a main power supply;
a power converter coupled to the input configured to convert between alternating current and direct current;
a power inverter coupled to the power converter configured to convert between alternating current and direct current;
a hoist motor coupled to the power inverter configured to have a regenerative mode;
an isolated bi-directional dc/dc converter coupled between the power converter and the power inverter;
a battery coupled to the isolated bi-directional dc/dc converter; and
a processor coupled to the isolated bi-directional dc/dc converter;
wherein the processor is configured to change the mode of operation of the isolated bi-directional dc/dc converter depending on voltage sensed from the power converter and voltage sensed from the battery;
wherein the processor is further configured to:
monitor a voltage level of the battery;
based on a determination that the voltage level of the battery is below a second predetermined threshold and a determination that the voltage level of the main power supply is above the first predetermined threshold, charging the battery via the isolated bi-directional dc/dc converter.

10. The system of claim 9 wherein the level sufficient to drive the hoist motor in the rescue mode ranges from 70 to 300 volts.

11. The system of claim 9 wherein the processor is further configured to:
monitor a temperature of the battery; wherein:
charging the battery comprises:
determining an optimum charging cycle for the battery using the voltage level of the battery and the temperature of the battery; and
applying the optimum charging cycle to the battery.

12. The system of claim 9 wherein:
charging the battery comprises using power from the main power supply to charge the battery.

13. The system method of claim 9 wherein:
charging the battery comprises using power from the hoist motor operating in a regenerative mode to charge the battery.

14. The system of claim 9 wherein:
the isolated bi-directional dc/dc converter is configured to receive a line voltage as input and output a voltage optimal to charge the battery.

15. The system of claim 14 wherein the battery is a 48 volt battery and the voltage optimal to charge the battery is in the range of 50 to 55 volts.

16. The system of claim 14 wherein the line voltage is approximately 380 to 480 volts.

Assignees

• Otis Elevator Co

Inventors

• Agirman Ismail

Classifications

• H02J7/0091

  Electricity · mapped topic

• H02J7/0077

  Electricity · mapped topic

• 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

• B66B5/021

  the abnormal operating conditions being independent of the system (alarm systems in general G08B) · CPC title

• B66B1/34

  Details {, e.g. call counting devices, data transmission from car to control system, devices giving information to the control system} · CPC title