System and method for fault isolation and leakage current detection

• US 7,924,019 B2
• Filed: 12/23/2008
• Issued: 04/12/2011
• Est. Priority Date: 01/16/2008
• Status: Active Grant

• Current Assignee: Lear Corporation
• Original Assignee: Lear Corporation
• Inventors: Darroman, Yann, Trenchs Magana, Albert
• Primary Examiner(s): Nguyen; Hoai-An D
• Application Number:
  US12/342,110
• Publication Number:
  US 20090179655A1
• Time in Patent Office: 840 Days
• Field of Search: 324/503, 324/500, 324/522, 324/555, 324/509, 324/510, 324/537, 324/772, 702/1, 702/57, 702/58, 702/185, 702/183, 702/182, 702/127, 702/117, 702/108, 701/22, 701/29
• US Class Current: 324/503
• CPC Class Codes: G01R 31/42 AC power supplies
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: H02H 11/005 in case of too low isolation resistance, too high load, short-circuit; earth fault
• CPC Class Codes: H02H 5/12 responsive to undesired approach to, or touching of, live parts by living beings

Abstract

An inverter system for a vehicle including a housing, a primary stage, a secondary stage and a fault detection circuit is provided. The primary stage is configured to receive a first voltage signal from an energy power source to generate a second voltage signal. The secondary stage is configured to generate a third voltage signal in response to the second voltage signal. At least one of the primary and the secondary stages define at least one resistance point for discharging leakage current responsive to generating the third voltage signal. The fault detection circuit is configured to electrically couple the primary stage and the secondary stage to provide the second voltage signal to the secondary stage and to measure a portion of the third voltage signal to determine whether the leakage current being discharged through the at least one resistance point is within a predetermined current range.

Claims

1. An inverter system for a vehicle comprising:

a housing;

a primary stage positioned within the housing and being configured to receive a first voltage signal from an energy power source to generate a second voltage signal;

a secondary stage positioned within the housing and configured to generate a third voltage signal in response to the second voltage signal, wherein at least one of the primary and the secondary stages defines at least one resistance point for discharging leakage current responsive to generating the third voltage signal; and

a fault detection circuit configured to electrically couple the primary stage and the secondary stage to provide the second voltage signal to the secondary stage and to measure a portion of the third voltage signal to determine whether the leakage current being discharged through the at least one resistance point is within a predetermined current range.

2. The inverter system of claim 1 wherein the fault detection circuit includes a switching device and at least one resistor, and wherein the switching device is configured to electrically couple the primary stage to the secondary stage to present the third voltage signal to the at least one resistor to generate the portion of the third voltage signal.

3. The inverter system of claim 2 wherein the fault detection circuit includes a controller configured to measure the portion of the third voltage signal across the at least one resistor and to determine whether the measured portion of the third voltage signal is within a predetermined voltage range.

4. The inverter system of claim 3 wherein the controller is further configured to determine that the leakage current is within a predetermined current range in the event the measured portion of the third voltage signal is within the predetermined voltage range.

5. The inverter system of claim 3 wherein the controller is further configured to determine that the leakage current is not within the predetermined current range if the measured portion of the third voltage signal is not within the predetermined voltage range.

6. The inverter system of claim 5 wherein the controller is further configured to disable the operation of generating the third voltage signal in response to determining that the measured portion of the third voltage signal is not within the predetermined voltage range.

7. The inverter system of claim 1 wherein the housing is metal.

8. The inverter system of claim 1 wherein the first voltage signal is a first DC based voltage signal and the third signal is at least one of a second DC based voltage signal and an AC based voltage output signal.

9. An inverter system for a vehicle comprising:

an electrically conductive housing;

a primary stage positioned within the housing and being configured to receive a first voltage signal from an energy power source to generate a second voltage signal;

a secondary stage positioned within the housing and configured to generate a third voltage signal in response to the second voltage signal, wherein at least one of the primary and the secondary stages defines at least one resistance point for discharging leakage current responsive to generating the third voltage signal; and

a fault detection circuit configured to electrically couple the primary stage and the secondary stage to provide the second voltage signal to the secondary stage and to measure a portion of the third voltage signal to determine whether the leakage current being discharged through the at least one resistance point is within a predetermined current range.

10. The inverter system of claim 9 wherein the fault detection circuit comprises a switching device and a least one resistor, wherein the switching device is configured to electrically couple the primary stage and the second stage to present the third voltage signal to the at least one resistor to generate the portion of the third voltage signal.

11. The inverter system of claim 10 wherein the fault detection circuit further comprises a controller configured to control the switching device to present the third voltage signal to the at least one resistor in response to detecting an engine ‘

ON’

condition.

12. The inverter system of claim 11 wherein the controller is further configured to measure the portion of the third voltage signal across the at least one resistor and to determine whether the measured portion of the third voltage signal is within a predetermined voltage range.

13. The inverter system of claim 12 wherein the controller is further configured to enable the generation of the third voltage signal in response to determining that the measured portion of the third voltage signal is within the predetermined voltage range.

14. The inverter system of claim 12 wherein the controller is further configured to disable the operation of generating the third voltage signal in response to determining that the measured portion of third voltage signal is not within the predetermined voltage range.

15. The inverter system of claim 9 wherein the housing is metal.

16. The inverter system of claim 9 wherein the first voltage signal is a first DC based voltage signal and the third voltage signal is at least one of a second DC based voltage signal and an AC based voltage output signal.

17. An inverter system for a vehicle comprising:

a housing;

a primary stage positioned within the housing and being configured to receive a DC voltage signal from an energy power source to generate a low AC voltage signal;

a secondary stage positioned within the housing and configured to generate a high AC voltage signal in response to the low AC voltage signal, wherein at least one of the primary and the secondary stages defines at least one resistance point for discharging leakage current responsive to generating the high AC voltage signal; and

a fault detection circuit configured to electrically couple the primary stage and the secondary stage to provide the low AC voltage signal to the secondary stage to measure a portion of the high AC voltage signal to determine whether the leakage current being discharged through the at least one resistance point is within a predetermined current range.

18. The inverter system of claim 17 wherein the fault detection circuit includes a switching device and at least one resistor, wherein the switching device is configured to electrically couple the primary stage to the secondary stage to present the high AC voltage signal to the at least one resistor to generate the portion of the high AC voltage signal.

19. The inverter system of claim 18 wherein the fault detection circuit includes a controller configured to measure the portion of the high AC voltage signal across the at least one resistor and to determine whether the measured portion of the high AC voltage signal is within a predetermined voltage range.

20. The inverter system of claim 19 wherein the controller is further configured to disable the operation of generating the high AC voltage signal in response to determining that the measured portion of the high AC voltage signal is not within the predetermined voltage range.