Control method for current-limiting control circuit and electrical system

Patent metadata

Field	Value
Publication number	US-12401188-B2
Application number	US-202118016236-A
Country	US
Kind code	B2
Filing date	Jul 12, 2021
Priority date	Nov 9, 2020
Publication date	Aug 26, 2025
Grant date	Aug 26, 2025

Abstract

The present disclosure provides a control method for a current-limiting control circuit and an electrical system. The current-limiting control circuit includes a high voltage side connected with a direct-current (DC) bus, a low voltage side connected with a load, and a regulating unit connected with the high voltage side and the low voltage side, the regulating unit including at least one MOS transistor, and the control method includes: detecting current I 0 of the current-limiting control circuit; determining whether the current I 0 is greater than a preset current I; and determining that the current-limiting control circuit has a short circuit fault, and entering a current limiting control mode to limit a persistent growth of the current, in a case where the current I 0 is greater than the preset current I.

First claim

What is claimed is:

1. A control method for a current-limiting control circuit, the current-limiting control circuit comprising a high voltage side connected with a direct-current (DC) bus, a low voltage side connected with a load, and a regulating unit connected with the high voltage side and the low voltage side, the regulating unit comprising at least one MOS transistor, wherein the control method comprises:
detecting current I 0 of the current-limiting control circuit;
determining whether the current I 0 is greater than a preset current I; and
determining that the current-limiting control circuit has a short circuit fault, and entering a current limiting control mode to limit a persistent growth of the current I 0 , in a case where the current I 0 is greater than the preset current I,
wherein the current limiting control mode comprises a primary side voltage droop control mode used to adjust current of the high voltage side, and the control method comprises:
detecting whether there is a voltage across the load before entering the current limiting control mode; and
determining that the DC bus has a short circuit fault, and entering the primary side voltage droop control mode, in a case where there is a voltage across the load.

2. The control method according to claim 1 , further comprising:
determining that the current-limiting control circuit works normally and entering a bidirectional conduction mode to achieve a bidirectional conduction between the low voltage side and the high voltage side through the MOS transistor and a parasitic diode on the MOS transistor, in a case where the current I0 is less than the preset current I.

3. The control method according to claim 1 , wherein the current limiting control mode comprises: a secondary side voltage droop control mode and the control method comprises:
detecting whether there is a voltage across the load before entering the current limiting control mode; and
determining that the load has a short circuit fault, and entering the secondary side voltage droop control mode, which is used to adjust current of the low voltage side, in a case where there is no voltage across the load.

4. The control method according to claim 3 , wherein the secondary side voltage droop control mode comprises:
entering a second droop control stage, and adjusting an input current of the MOS transistor by adjusting a duty cycle of the MOS transistor to reduce a voltage of the low voltage side and keep an output power of the low voltage side unchanged;
determining whether the current I 0 has reached a threshold current I 1 , wherein the threshold current I 1 is a maximum working current that the current-limiting control circuit can withstand; and
entering a second constant current control stage, and performing a PI adjustment by adjusting the duty cycle of the MOS transistor, to keep current of the low voltage side unchanged, in a case where the current I 0 has reached a threshold current I 1 .

5. The control method according to claim 1 , wherein the primary side voltage droop control mode comprises:
entering a first droop control stage, and adjusting an input current of the MOS transistor by adjusting a duty cycle of the MOS transistor to reduce a voltage of the high voltage side and keep an output power of the high voltage side unchanged;
determining whether the current I 0 has reached a threshold current I 1 , wherein the threshold current I 1 is a maximum working current that the current-limiting control circuit can withstand; and
entering a first constant current control stage, and performing a PI adjustment by adjusting the duty cycle of the MOS transistor, to keep current of the high voltage side unchanged, in a case where the current I 0 has reached a threshold current I 1 .

6. The control method according to claim 1 , further comprising:
determining whether operating parameters of the current-limiting control circuit meet a maximum power control condition before entering the current limiting control mode; and
entering a maximum power tracking control mode in a case where the operating parameters of the current-limiting control circuit meet the maximum power control condition, and entering the current limiting control mode in a case where the operating parameters of the current-limiting control circuit do not meet the maximum power control condition.

7. The control method according to claim 6 , wherein the maximum power tracking control mode comprises:
detecting an output power of the low voltage side to obtain a first detection power P 0 , adjusting a duty cycle of the MOS transistor to change the output power of the low voltage side, and detecting the output power the low voltage side again to obtain a second detection power P 1 , in a case where the current I 0 reaches the threshold current I 1 ;
determining whether the first detection power P 0 is greater than the second detection power P 1 ;
adjusting the duty cycle of the MOS transistor to maintain the output power of the low voltage side to the first detection power P 0 , in a case where the first detection power P 0 is greater than the second detection power P 1 , and adjusting the duty cycle of the MOS transistor to maintain the output power of the low voltage side to the second detection power P 1 , in a case where the first detection power P 0 is lower than the second detection power P 1 .

8. An electrical system, in which the control method of a current-limiting control circuit according to claim 1 is adopted.

9. The electrical system according to claim 8 , comprising the DC bus and at least one load connected to the DC bus, wherein the high voltage side of the current-limiting control circuit is connected to the DC bus, and the low voltage side of the current-limiting control circuit is connected to the at least one load.

10. An electrical system, comprising a memory and a processor, wherein the memory stores computer programs, which when executed by the processor, cause the processor to perform the control method of a current-limiting control circuit according to claim 1 .

11. The electrical system according to claim 10 , wherein the memory further stores computer programs, which when executed by the processor, cause the processor to:
determine that the current-limiting control circuit works normally and entering a bidirectional conduction mode to achieve a bidirectional conduction between the low voltage side and the high voltage side through the MOS transistor and a parasitic diode on the MOS transistor, in a case where the current I 0 is less than the preset current I.

12. The electrical system according to claim 10 , wherein the current limiting control mode comprises: a secondary side voltage droop control mode and the computer programs when executed by the processor, cause the processor to:
detect whether there is a voltage across the load before entering the current limiting control mode; and
determine that the load has a short circuit fault, and enter the secondary side voltage droop control mode, which is used to adjust current of the low voltage side, in a case where there is no voltage across the load.

13. The electrical system according to claim 12 , wherein the secondary side voltage droop control mode comprises:
entering a second droop control stage, and adjusting an input current of the MOS transistor by adjusting a duty cycle of the MOS transistor to reduce a voltage of the low voltage side and keep an output power of the low voltage side unchanged;
determining whether the current I 0 has reached a threshold current I 1 , wherein the threshold current I 1 is a maximum working current that the current-li

Assignees

• Gree Electric Appliances Inc Zhuhai

Inventors

• Zhao Zhigang
• Liao Junhao
• Lai Yuanhua
• Lin Baowei
• Liu Xia
• Wang Chunyang

Classifications

• H02H3/087

  for DC applications · CPC title

• H02H1/0007

  concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445) · CPC title

• H02H7/1213

  for DC-DC converters · CPC title

• H02H3/044

  Checking correct functioning of protective arrangements, e.g. by simulating a fault (for differential current circuit breakers H02H3/335) · CPC title

• H02H9/025 Primary

  Current limitation using field effect transistors · CPC title