METHOD AND APPARATUS FOR BALANCING CURRENT THROUGH AN INTERRUPT DEVICE

• US 20090323239A1
• Filed: 06/26/2008
• Published: 12/31/2009
• Est. Priority Date: 06/26/2008
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: MARKYVECH, Craig R.
• Granted Patent: US 8,064,178 B2
• Time in Patent Office: Days
• US Class Current: 361/57
• CPC Class Codes: B60L 3/00 Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption methods or circuit arrangements for monitoring or controlling batteries or fuel cells B60L58/00
• CPC Class Codes: B60L 3/0069 relating to the isolation, e.g. ground fault or leak current
• CPC Class Codes: B60L 3/0092 with use of redundant elements for safety purposes
• CPC Class Codes: B60L 3/04 Cutting off the power supply under fault conditions protective devices and circuit arrangements in general H01H; H02H
• CPC Class Codes: B60L 53/16 Connectors, e.g. plugs or sockets, specially adapted for charging electric vehicles
• CPC Class Codes: B60L 58/00 Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/0029 with safety or protection devices or circuits
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

Systems and methods are provided for balancing current through a first conductor and a second conductor. A method comprises determining if a first current through the first conductor is greater than a second current through the second conductor by more than a threshold value. The first current and the second current are received from a ground fault current interrupt device. The method further comprises increasing the second current in response to determining that the first current is greater than the second current by more than the threshold value.

Claims

1. A charge current interrupt device comprising:

a current sensor adapted to be coupled to a first conductor and a second conductor, the current sensor being configured to obtain a first current through the first conductor and a second current through the second conductor;

a first switched load coupled between the first conductor and a reference potential, the first switched load comprising a first load element; and

a switching control coupled to the current sensor and the first switched load, the switching control being configured to activate the first switched load, such that the first load element is coupled between the first conductor and the reference potential, if the second current is greater than the first current by more than a threshold value.

2. The charge current interrupt device of claim 1, further comprising a second switched load coupled to the switching control, the second switched load being coupled between the second conductor and the reference potential and the second switched load comprising a second load element, wherein the switching control is configured to activate the second switched load, such that the second load element is coupled between the second conductor and the reference potential, if the first current is greater than the second current by more than the threshold value.

3. The charge current interrupt device of claim 1, wherein the switching control is configured to deactivate the first switched load, such that the first load element is disconnected from the first conductor, if a difference between the first current and the second current is less than a second threshold value.

4. The charge current interrupt device of claim 3, wherein the second threshold value is less than 1 mA.

5. The charge current interrupt device of claim 1, wherein the threshold value is less than 5 mA.

6. The charge current interrupt device of claim 1, further comprising a controller adapted to be coupled to the first conductor and the second conductor, wherein the controller is configured to prevent current from flowing through the charge current interrupt device if a difference between the first current and the second current is greater than a second threshold value.

7. The charge current interrupt device of claim 1, wherein the switching control is configured to deactivate the first switched load, such that the first load element is disconnected from the first conductor, if the second current is greater than the first current by more than a second threshold value.

8. The charge current interrupt device of claim 7, wherein the second threshold value is approximately 20 mA.

9. The charge current interrupt device of claim 1, wherein the first load element is selected from a group consisting of a resistor, a variable resistor, an inductor, and a semiconductor device.

10. The charge current interrupt device of claim 1, wherein the first conductor and the second conductor are adapted to be coupled to a ground fault current interrupt device, the ground fault current interrupt device being configured to prevent current flow to the first conductor and the second conductor if a difference between the first current and the second current is greater than a trip point.

11. The charge current interrupt device of claim 10, wherein the threshold value is between 0 mA and the trip point.

12. A method for balancing current through a first conductor and a second conductor, the first conductor and the second conductor being coupled to a ground fault current interrupt device, the method comprising:

determining if a first current through the first conductor is greater than a second current through the second conductor by more than a threshold value, the first current and the second current being received from the ground fault current interrupt device; and

increasing the second current in response to determining that the first current is greater than the second current by more than the threshold value.

13. The method of claim 12, further comprising measuring the first current and the second current.

14. The method of claim 12, wherein increasing the second current further comprises coupling a switched load between the second conductor and a reference potential.

15. The method of claim 14, further comprising decoupling the switched load from the second conductor if an output current differential is less than a second threshold value.

16. The method of claim 12, further comprising:

determining if the second current is greater than the first current by more than the threshold value; and

increasing the first current in response to determining that the 5 second current is greater than the first current by more than the threshold value.

17. The method of claim 16, wherein increasing the first current further comprises coupling a second switched load between the first conductor and a reference potential.

18. The method of claim 17, further comprising decoupling the second switched load if a difference between the first current and the second current is less than a second threshold value.

19. A charge current interrupt device, the charge current interrupt device comprising:

means for measuring current through a plurality of conductors coupled to the charge current interrupt device; and

means for increasing a first current through a first conductor of the plurality of conductors if the first current is less than a second current though a second conductor of the plurality of conductors by more than a threshold value.

20. The charge current interrupt device of claim 19, further comprising means for preventing current flow from the charge current interrupt device if a difference between the first current and the second current is greater than a trip point.