Granted Patent B2

US 12,334,818 · App. 17/984,166 · Granted Jun 17, 2025

Inventors: Akshay Sarin (Auburn Hills, MI); Alan B. Martin (Washington, MI); Joseph Berg (Highland, MI)

Assignee: GM Global Technology Operations LLC

H02M3/155H02M1/0009

Abstract

Claims (75)

1. A pre-charge system for a DC electric power system, the pre-charge system comprising:

a high-voltage electric power bus composed as a positive bus link and a negative bus link, wherein the high-voltage electric power bus electrically connects to an external bus via the positive bus link and the negative bus link;

a contactor including a first switch arranged to control electric power through the positive bus link, and a second switch arranged to control electric power through the negative bus link;

a pre-charge resistor, the pre-charge resistor being arranged in parallel with the first switch;

a voltage sensor arranged to monitor electrical potential between the positive bus link and the negative bus link; and

a controller, the controller operatively connected to the first and second switches, and in communication with the voltage sensor, the controller including an instruction set, the instruction set being executable to:

activate the second switch;

periodically monitor the electrical potential;

determine a time-rate of change in the electrical potential; and

close the first switch when the time-rate of change in the electrical potential is less than a first threshold.

2. The pre-charge system of claim 1 , further comprising the instruction set being executable to:

monitor an elapsed time starting from activation of the second switch; and

open the second switch when the elapsed time from activation of the second switch is greater than a time threshold and the time-rate of change in the electrical potential is greater than the first threshold.

3. The pre-charge system of claim 2 , further comprising the instruction set being executable to indicate a fault when the second switch is opened.

4. The pre-charge system of claim 1 , further comprising a timer; wherein the instruction set is executable to:

initiate the timer coincident with activation of the second switch; and

periodically monitor the electrical potential only when the timer exceeds a time threshold.

5. The pre-charge system of claim 1 , further comprising a non-rechargeable electric power source, wherein the non-rechargeable electric power source is electrically connected to the positive bus link and the negative bus link of the high-voltage electric power bus.

6. The pre-charge system of claim 5 , wherein the non-rechargeable electric power source comprises one of a fuel cell stack or a photovoltaic panel.

7. The pre-charge system of claim 1 , further comprising the instruction set being executable to:

determine, via a current sensor, an electrical current in the positive bus link;

determine a time-rate of change in the electrical current; and

close the first switch when the time-rate of change in the electrical current is less than a current threshold.

8. A pre-charge system for a DC electric power system, the pre-charge system consisting of:

a high-voltage power bus composed as a positive bus link and a negative bus link, wherein the high-voltage power bus electrically connects to an external bus via the positive bus link and the negative bus link;

a contactor including a first switch arranged to control electric power through the positive bus link, and a second switch arranged to control electric power through the negative bus link;

a pre-charge resistor, the pre-charge resistor being arranged in parallel with the second switch;

a voltage sensor arranged to monitor electrical potential between the positive bus link and the negative bus link; and

a controller, the controller operatively connected to the first and second switches, and in communication with the voltage sensor;

wherein the controller includes an instruction set, the instruction set being executable to:

activate the first switch;

periodically monitor the electrical potential;

determine a time-rate of change in the electrical potential; and

close the second switch when the time-rate of change in the electrical potential is less than a first threshold.

9. The pre-charge system of claim 8 , wherein the instruction set is executable to:

monitor an elapsed time starting from activation of the second switch; and

open the second switch when the elapsed time from activation of the second switch is greater than a time threshold and the time-rate of change in the electrical potential is greater than the first threshold.

10. The pre-charge system of claim 8 , wherein the instruction set is executable to indicate a fault when the first switch is opened.

11. The pre-charge system of claim 8 , wherein the controller includes a timer; and wherein the instruction set is executable to:

initiate the timer coincident with activation of the first switch; and

periodically monitor the electrical potential only when the timer exceeds a time threshold.

12. The pre-charge system of claim 8 , further comprising the instruction set being executable to:

periodically monitor electrical current;

determine a time-rate of change in the electrical current; and

close the first switch when the time-rate of change in the electrical current is less than a current threshold.

13. The pre-charge system of claim 8 , wherein the instruction set is executable to:

monitor, via the timer, an elapsed time starting from activation of the first switch; and

open the first switch when the elapsed time from activation of the second switch is greater than a time threshold and the time-rate of change in the electrical potential is greater than the first threshold.

14. The pre-charge system of claim 13 , wherein the instruction set is executable to indicate a fault when the first switch is opened.

15. The pre-charge system of claim 8 , further comprising a non-rechargeable electric power source, wherein the non-rechargeable electric power source is electrically connected to the positive bus link and the negative bus link of the high-voltage electric power bus; and

wherein the non-rechargeable electric power source comprises one of a fuel cell stack or a photovoltaic panel.

16. A method for pre-charging an external electric bus, the method comprising:

arranging a high-voltage power bus including a positive bus link and a negative bus link between a DC power source and the external electric bus, wherein the high-voltage power bus electrically connects to the external bus via the positive bus link and the negative bus link;

arranging a first switch to control electric power through the positive bus link, and arranging a second switch to control electric power through the negative bus link;

arranging a pre-charge resistor in parallel with the first switch;

activating the second switch;

determining an electrical current in the positive bus link;

determining a time-rate of change in the electrical current; and

closing the first switch when the time-rate of change in the electrical current is less than a current threshold.

17. The method of claim 16 , further comprising:

monitoring an elapsed time starting from the activating of the second switch;

opening the second switch when the elapsed time from activation of the second switch is greater than a time threshold and the time-rate of change in the electrical current is greater than the first threshold; and

indicating a fault when the second switch is opened.

18. The method of claim 16 , further comprising:

initiating a timer coincident with activation of the second switch; and

periodically determining the electrical current only when the timer exceeds a time threshold.

19. The method of claim 16 , further comprising:

activating the second switch;

periodically determining the electrical current;

determining a time-rate of change in the electrical current; and

closing the first switch when the time-rate of change in the electrical current is less than a current threshold.

20. The method of claim 19 , further comprising:

monitoring an elapsed time starting from activation of the second switch;

opening the second switch when the elapsed time from activation of the second switch is greater than a time threshold and the time-rate of change in the electrical current is greater than the current threshold; and

indicating a fault when the second switch is opened.

Assignments (1)

Continuity (1)

References Cited (12)