METHOD AND APPARATUS FOR DETECTING FAULTS IN A CURRENT SENSING DEVICE

• US 20090144002A1
• Filed: 11/07/2007
• Published: 06/04/2009
• Est. Priority Date: 11/07/2007
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Zettel, Andrew M., Miller, Michael J., Padmanabhan, Jayanthi
• Granted Patent: US 8,005,632 B2
• Time in Patent Office: Days
• US Class Current: 702/64
• CPC Class Codes: G01R 31/2829 Testing of circuits in sensor or actuator systems testing of apparatus for measuring electric or magnetic variables G01R35/00; testing of indicating or recording apparatus G01D; in airbag systems B60R21/0173; checking gas analysers G01N33/007; monitoring or fail-safe circuits for electromagnets H01F7/1844
• CPC Class Codes: G01R 31/50 Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections testing of sparking plugs H01T13/58
• CPC Class Codes: G01R 35/00 Testing or calibrating of apparatus covered by the other groups of this subclass

Abstract

A method and article of manufacture are provided to monitor a sensing system operative to monitor electrical current in a transmission line between an electrical storage device and an electrical machine. The sensing system comprises first and second sensors, operative to monitor first and second ranges of electrical current. The method comprises determining outputs of the first and second sensors are valid, and comparing outputs of the first and second sensors when current is substantially zero. The method comprises comparing magnitudes of the outputs of the first and second sensors when the monitored electrical current, and monitoring polarity of each of the outputs of the first and second sensors.

Claims

1. Method to monitor a sensing system operative to monitor electrical current in a transmission line between an electrical storage device and an electrical machine comprising a first sensor operative to monitor a first range of electrical current and a second sensor operative to monitor a second range of electrical current, the method comprising:

determining outputs of the first and second sensors are valid;

comparing outputs of the first and second sensors when current in the transmission line is substantially zero;

comparing magnitudes of the outputs of the first and second sensors when the monitored electrical current is within a monitoring range common to the first and the second sensors; and

monitoring polarity of each of the outputs of the first and second sensors.

2. The method of claim 1, wherein determining outputs of the first and second sensors are valid comprises monitoring the outputs of the first and second sensors, and, identifying an absence of either of a short circuit and an open circuit in the outputs of the first and second sensors.

3. The method of claim 2, further comprising:

identifying a fault when the output of either of the first and second sensors is invalid, and, discontinuing further monitoring.

4. The method of claim 1, wherein comparing outputs of the first and second sensors when current in the transmission line is substantially zero comprises monitoring outputs of the first and second sensors when an open circuit is present in the transmission line.

5. The method of claim 4, further comprising:

identifying a fault when the output of either of the first and second sensors is not substantially zero, and, discontinuing further monitoring.

6. The method of claim 1, wherein comparing magnitudes of the outputs of the first and second sensors when the monitored electrical current is within a monitoring range common to both the first and the second sensors further comprises determining a difference between the outputs of the first and second sensors does not exceed measurement accuracies of the first and second sensors.

7. The method of claim 6, further comprising:

identifying a fault when the difference between the outputs of the first and second sensors exceeds the measurement accuracies for the first and second sensors, and, discontinuing further monitoring.

8. The method of claim 1, wherein monitoring the polarity of each of the outputs of the first and second sensors further comprises monitoring voltage in the electrical storage device during an elapsed time period, and, comparing a direction of change in the monitored voltage of the electrical storage device to a direction of change in the outputs of the first and second sensors.

9. The method of claim 8, further comprising:

identifying a fault when the direction of change in the output of either of the first and second sensors does not correlate to the direction of change of the monitored voltage of the electrical storage device, and, discontinuing further monitoring.

10. The method of claim 1, wherein the first sensor operative to monitor a first range of electrical current comprises the first sensor operative to monitor a range of current restricted between approximately +/−

30 amperes and having a measurement accuracy of 0.3 amperes.

11. The method of claim 1, wherein the second sensor operative to monitor a second range of electrical current comprises the second sensor operative to monitor a range of current restricted between approximately +/−

300 amperes and having a measurement accuracy of 3.0 amperes.

12. Article of manufacture, comprising a storage medium having a computer program encoded therein for effecting a method to monitor operation of an sensing system operative to monitor electrical current in a transmission line between an electrical storage device and an electrical machine comprising a first sensor operative to monitor a first range of electrical current and a second sensor operative to monitor a second range of electrical current, the program comprising:

code for determining outputs of the first and second sensors are valid;

code for comparing outputs of the first and second sensors when current in the transmission line is substantially zero;

code for comparing magnitudes of the outputs of the first and second sensors when the monitored electrical current is within a monitoring range common to the first and the second sensors; and

code for monitoring polarity of each of the outputs of the first and second sensors.

13. The article of manufacture of claim 12, wherein the code for comparing outputs of the first and second sensors when current in the transmission line is substantially zero comprises:

code for monitoring outputs of the first and second sensors when an open circuit is present in the transmission line.

14. The article of manufacture of claim 12, wherein the code for comparing magnitudes of the outputs of the first and second sensors when the monitored electrical current is within a monitoring range common to both the first and the second sensors further comprises:

code for determining a difference between the outputs of the first and second sensors does not exceed measurement accuracies of the first and second sensors.

15. The article of manufacture of claim 12, wherein code for monitoring the polarity of each of the outputs of the first and second sensors further comprises code for monitoring voltage in the electrical storage device during an elapsed time period, and, code for comparing a direction of change in the monitored voltage of the electrical storage device to a direction of change in the outputs of the first and second sensors.

16. Powertrain system, comprising:

an electrical storage device electrically connected to an electrical machine operative to transmit motive torque to a vehicle driveline;

a sensing system operative to monitor electrical current in a transmission line between the electrical machine and the electrical storage device;

a control system;

adapted to monitor the electrical storage device and control the electrical machine; and

including a control module comprising a storage medium having a computer program encoded therein for effecting a method to monitor operation of the sensing system comprising a first sensor operative to monitor a first range of electrical current and a second sensor operative to monitor a second range of electrical current, the program comprising;

code for determining outputs of the first and second sensors are valid;

code for comparing outputs of the first and second sensors when current in the transmission line is substantially zero;

code for comparing magnitudes of the outputs of the first and second sensors when the monitored electrical current is within a monitoring range common to the first and the second sensors; and

code for monitoring polarity of each of the outputs of the first and second sensors.

17. The powertrain system of claim 16, wherein the first sensor and the second sensor each comprise open-loop Hall-effect sensors.

18. The powertrain system of claim 17, wherein the first sensor is operative to monitor a range of current restricted between approximately +/−

30 amperes.

19. The powertrain system of claim 17, wherein the second sensor is operative to monitor a range of current restricted between approximately +/−

300 amperes.