Elevator speed control

Patent metadata

Field	Value
Publication number	US-9957131-B2
Application number	US-201214651284-A
Country	US
Kind code	B2
Filing date	Dec 13, 2012
Priority date	Dec 13, 2012
Publication date	May 1, 2018
Grant date	May 1, 2018

Abstract

Embodiments are directed to calculating a current associated with a motor of an elevator based on an output of a speed regulator, and controlling the elevator based on the current. Embodiments are directed to examining a feeder current obtained via a converter current sensor of a regenerative drive during a peak power condition, and regulating a speed of an elevator based on the feeder current.

First claim

What is claimed is:

1. A method comprising:
calculating a current associated with a motor of an elevator based on an output of a speed regulator; and
controlling the elevator based on the current;
comparing the current to a limit associated with at least one of a drive and the motor,
wherein controlling the elevator comprises finishing an elevator run when the comparison indicates that the current is less than the limit, and
wherein controlling the elevator comprises at least one of (i) halting the elevator, (ii) slowly bringing the elevator to a stop and running the elevator back to an initial position, and (iii) reducing a speed reference and having the elevator proceed to an initial landing, when the comparison indicates that the current is greater than the limit.

2. The method of claim 1 , further comprising:
calculating a motor power associated with the motor; and
measuring a bus voltage,
wherein the current is calculated based on the motor power and the bus voltage.

3. The method of claim 2 , wherein the motor power is based on a motor torque constant, associated with the motor and an encoder speed calculation, and wherein the current is calculated based on a power factor parameter and an efficiency parameter associated with the motor.

4. The method of claim 1 , further comprising:
calculating the current based on current references associated with the motor.

5. A system comprising:
a speed regulator configured to receive a speed feedback and a speed reference and generate a torque current reference;
a controller configured to control an elevator's operation based on the torque current reference;
wherein the controller is configured to compare the torque current reference to a limit associated with at least one of a drive and the motor,
wherein the controller is configured to perform:
controlling the elevator comprises finishing an elevator run when the comparison indicates that the torque current reference is less than the limit, and
controlling the elevator comprises at least one of (i) halting the elevator, (ii) slowly bringing the elevator to a stop and running the elevator back to an initial position, and (iii) reducing a speed reference and having the elevator proceed to an initial landing, when the comparison indicates that the current is greater than the limit.

6. The system of claim 5 , wherein the controller is configured to control the elevator's operation based on a comparison of the torque current reference to two different thresholds, wherein a first of the thresholds is associated with holding a car of the elevator, and wherein a second of the thresholds is associated with an acceleration of the car.

7. The system of claim 5 , wherein the controller is configured to control the elevator's operation based on a calculated motor power associated with a motor of the elevator and a measured bus voltage.

8. The system of claim 7 , wherein the measured bus voltage is associated with a battery voltage in a battery-based drive.

9. The system of claim 7 , wherein the calculated motor power is based on a motor torque constant associated with the motor and an encoder speed calculation, and wherein the controller is configured to calculate a current associated with the motor based on the calculated motor power and a power factor parameter and an efficiency parameter associated with the motor.

10. The system of claim 5 , wherein the controller is configured to control the elevator's operation based on a summation of a maximum torque per ampere current and a motor voltage regulator output current.

Assignees

• Otis Elevator Co

Inventors

• Agirman Ismail
• Piedra Edward

Classifications

• B66B1/308 Primary

  with AC powered elevator drive · CPC title

• B66B5/145

  electrical · CPC title

• B66B1/30 Primary

  effective on driving gear {, e.g. acting on power electronics, on inverter or rectifier controlled motor} · CPC title