Current limit strategy for hoist application

Patent metadata

Field	Value
Publication number	US-12407286-B2
Application number	US-202318356334-A
Country	US
Kind code	B2
Filing date	Jul 21, 2023
Priority date	Mar 22, 2023
Publication date	Sep 2, 2025
Grant date	Sep 2, 2025

Abstract

A hoist application system is provided. The hoist application system includes a motor drive unit, which is receptive of a final duty command and which drives a motor in accordance with the final duty command, a closed-loop control unit configured to generate a closed-loop duty command, an open-loop control unit configured to generate an open-loop duty command and a switch logic unit. The switch logic unit is receptive of direct current (DC) system information, the closed-loop duty command and the open-loop duty command, and is configured to generate the final duty command from one of the closed-loop duty command and the open-loop duty command based on the DC system information.

First claim

What is claimed is:

1. A hoist application system, comprising:
a motor drive unit, which is receptive of a final duty command and which drives a motor in accordance with the final duty command;
a closed-loop control unit configured to generate a closed-loop duty command;
an open-loop control unit configured to generate an open-loop duty command; and
a switch logic unit, which is receptive of direct current (DC) system information, the closed-loop duty command and the open-loop duty command, and which is configured to generate the final duty command from one of the closed-loop duty command and the open-loop duty command based on the DC system information,
wherein:
the switch logic unit transitions from the closed-loop duty command to the open-loop duty command when a DC-link current exceeds a threshold value from the DC system for a predetermined time, and
the switch logic unit transitions from the open-loop duty command to the closed-loop duty command when the DC-link current is lower than the threshold value for the predetermined time and closed-loop operation is possible without crossing the threshold value.

2. The hoist application system according to claim 1 , wherein the closed-loop control unit is configured to calculate the closed-loop duty command based on an error between a commanded motor speed and a measured motor speed.

3. The hoist application system according to claim 1 , wherein the open-loop control unit is configured to calculate the open-loop duty command using a fuzzy map algorithm.

4. The hoist application system according to claim 3 , wherein the fuzzy map algorithm considers a measured motor speed, the DC system information and a current version of the final duty command.

5. The hoist application system according to claim 1 , wherein the open-loop control unit is configured to calculate the open-loop duty command to achieve a gradual time-based duty cycle reduction.

6. The hoist application system according to claim 1 , wherein the threshold value is about 150 A.

7. The hoist application system according to claim 1 , wherein the threshold value is 150 A.

8. A method of operating a hoist application system, the method comprising:
driving a motor in accordance with a final duty command;
generating, in a closed-loop control unit, a closed-loop duty command;
generating, in an open-loop control unit, an open-loop duty command; and
generating the final duty command from one of the closed-loop duty command and the open-loop duty command based on direct current (DC) system information,
wherein the generating of the final duty command comprises:
transitioning from the closed-loop duty command to the open-loop duty command when a DC-link current exceeds a threshold value from the DC system information for a predetermined time; and
transitioning from the open-loop duty command to the closed-loop duty command when the DC-link current is lower than the threshold value for the predetermined time and, for a commanded motor speed and a load applied on the system, the closed-loop operation is possible without crossing the threshold value.

9. The method according to claim 8 , wherein the generating of the closed-loop duty command comprises calculating the closed-loop duty command based on an error between a commanded motor speed and a measured motor speed.

10. The method according to claim 8 , wherein the generating of the open-loop duty command comprises calculating the open-loop duty command using a fuzzy map algorithm.

11. The method according to claim 10 , wherein the fuzzy map algorithm considers a measured motor speed, the DC system information and a current version of the final duty command.

12. The method according to claim 8 , wherein the generating of the open-loop duty command comprises calculating the open-loop duty command to achieve a gradual time-based duty cycle reduction.

13. The method according to claim 8 , wherein the threshold value is about 150 A.

14. The method according to claim 8 , wherein the threshold value is 150 A.

15. A method of operating a hoist application system, the method comprising:
driving a motor in accordance with a final duty command;
generating, in a closed-loop control unit, a closed-loop duty command;
generating, in an open-loop control unit, an open-loop duty command; and
generating the final duty command from one of the closed-loop duty command and the open-loop duty command based on direct current (DC) system information,
wherein the generating of the final duty command comprises one of switching from the closed-loop duty command to the open-loop duty command and switching from the open-loop duty command to the closed-loop duty command,
wherein:
the switching from the closed-loop duty command to the open-loop duty command comprises comparing a DC-link current to a threshold value from the DC system information and transitioning from the closed-loop duty command to the open-loop duty command in an event the DC-link current exceeds the threshold value for a predetermine time, and
the switching from the open-loop duty command to the closed-loop duty command comprises determining whether the DC system information indicates that a DC-link current is lower than a threshold value for a predetermined time and a closed-loop operation is possible without crossing the threshold value and switching from the open-loop duty command to the closed-loop duty command in an event the DC system information indicates that the DC-link current is lower than the threshold value for the predetermined time and, for a commanded motor speed and a load applied on the system, the closed-loop operation is possible without crossing the threshold value.

Assignees

• Hamilton Sundstrand Corp

Inventors

• Josyula Anil Prasad
• Vijay Ashish
• Kohli Vipul
• Brookes David Frederick

Classifications

• H02P21/001

  using fuzzy control · CPC title

• H02P21/18

  Estimation of position or speed · CPC title

• H02P27/085

  wherein the PWM mode is adapted on the running conditions of the motor, e.g. the switching frequency · CPC title

• H02P2205/07

  Speed loop, i.e. comparison of the motor speed with a speed reference · CPC title

• H02P21/22 Primary

  Current control, e.g. using a current control loop · CPC title