System and method to thermally protect a transistor in an electric drive vehicle

• US 8,442,712 B2
• Filed: 08/31/2011
• Issued: 05/14/2013
• Est. Priority Date: 08/31/2011
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Qian, Lewei
• Primary Examiner(s): Cheung, Mary
• Assistant Examiner(s): MAZZARA, ANNE MARIE
• Application Number:
  US13/222,785
• Publication Number:
  US 20130054059A1
• Time in Patent Office: 622 Days
• Field of Search: 702/136, 702/138, 374/178, 733/84, 701/22
• US Class Current: 701/22
• CPC Class Codes: B60L 2200/36 Vehicles designed to transport cargo, e.g. trucks
• CPC Class Codes: B60L 3/003 relating to inverters
• CPC Class Codes: B60L 3/0038 relating to sensors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H02H 7/222 for switches

Abstract

An electronic system for an electric drive mobile machine includes at least one transistor that emits heat, a pressure detector that generates a pressure signal, a temperature detector providing a first temperature signal indicative of the detected first temperature and a second temperature of or substantially adjacent to the transistor, and a controller configured to determine a temperature protection set point based upon the first temperature signal and the pressure signal and execute a control strategy for thermally protecting the transistor when the first temperature signal indicates that the first temperature reaches the temperature protection set point.

Claims

1. An electronic system for an electric drive mobile machine, the system comprising:

at least one transistor that emits heat;

at least one pressure detector disposed to detect pressure and generate a pressure signal;

at least one temperature detector disposed to detect a first temperature and provide a first temperature signal indicative of the detected first temperature, the first temperature signal further being indicative of a second temperature of or substantially adjacent to the transistor;

a controller configured to determine a temperature protection set point based upon the first temperature signal and the pressure signal, and to execute a control strategy for thermally protecting the at least one transistor when the first temperature signal indicates that the first temperature has reached the temperature protection set point.

2. The electronic system of claim 1 wherein the controller is configured to determine the temperature protection set point based upon predetermined data associating pressure with temperature along a curve.

3. The electronic system of claim 1 wherein the controller is configured to determine altitude based upon detected pressure, and to determine the temperature protection set point based upon predetermined data associating altitude with temperature.

4. The electronic system of claim 1 wherein the at least one transistor includes an insulated gate bipolar transistor.

5. The electronic system of claim 4 wherein the at least one temperature detector includes a resistance temperature detector.

6. The electronic system of claim 5 wherein the first temperature and the second temperature are substantially the same.

7. The electronic system of claim 5 further comprising a heatsink, the insulated gate bipolar transistor being disposed on the heatsink to provide a junction with the heatsink, the at least one temperature detector being disposed to detect the first temperature at the heatsink, the second temperature being indicative of the temperature at the junction.

8. A method of controlling the application of thermal protections for a heat emitting transistor in an electric drive mobile machine, the method comprising the steps of:

disposing the transistor in the electric drive mobile machine;

detecting a pressure substantially indicative of an air pressure surrounding the machine, and generating a pressure signal based upon the detected pressure;

detecting a first temperature, and providing a first temperature signal indicative of the detected first temperature, the first temperature signal further being indicative of a second temperature of or substantially adjacent to the transistor;

determining a temperature protection set point based upon the pressure signal and predetermined data associating pressure with temperature along a curve; and

generating a control strategy for thermally protecting the at least one heat emitting transistor when the first temperature signal indicates that the first temperature has reached the temperature protection set point.

9. The method of claim 8 wherein the determining step includes determining altitude based upon detected pressure.

10. The method of claim 9 wherein the transistor includes at least one insulated gate bipolar transistor, and detecting a first temperature step includes disposing at least one resistance temperature detector to detect the first temperature.

11. The method of claim 8 wherein the step of determining a temperature protection set point includes a step of determining a plurality of levels of temperature protection set points for respective levels of thermal protection, and the generating a control strategy includes generating a control strategy for thermally protecting the at least one heat emitting transistor at escalating levels when the first temperature signal indicates that that the first temperature has reached the respective levels of temperature protection set points.

12. The method of claim 8 wherein the transistor includes at least one insulated gate bipolar transistor, the disposing step includes disposing the insulated gate bipolar transistor on a heatsink, and the method further comprises the steps of disposing at least one pressure detector to detect the pressure indicative of the air pressure surrounding the machine, and disposing at least one resistance temperature detector to detect the first temperature at the heatsink, the second temperature being indicative of the temperature at a junction between the heatsink and the insulated gate bipolar transistor.

13. The method of claim 8 further including the step of executing the control strategy to thermally protect the transistor.

14. A controller for controlling thermal protection of at least one heat emitting transistor in an electric drive mobile machine, the controller including a computer-readable memory having thereon computer-executable instructions including:

instructions for receiving a pressure signal based upon a detected pressure;

instructions for receiving a first temperature signal indicative of a detected first temperature, the first temperature signal further being indicative of a second temperature of or substantially adjacent to the heat emitting transistor;

instructions for determining a temperature protection set point based upon the first temperature signal and the pressure signal; and

instructions for executing a control strategy for thermally protecting the at least one heat emitting transistor when the first temperature signal indicates that the first temperature has reached the temperature protection set point.

15. The controller according to claim 14 wherein the heat emitting transistor is an insulated gate bipolar transistor.

16. The controller according to claim 14 wherein the temperature signal is provided from a resistance temperature detector.

17. The controller according to claim 14 wherein the instructions for determining a temperature protection set point include instructions for determining a temperature protection set point based upon predetermined data associating pressure with temperature along a curve.

18. The controller according to claim 14 further including instructions for determining altitude based upon the pressure signal, and the instructions for determining the temperature protection set point include instructions for determining a temperature protection set point based upon the first temperature signal and the altitude determined based upon the pressure signal.

19. The controller according to claim 18 wherein the heat emitting transistor is an insulated gate bipolar transistor, and the temperature signal is provided from a resistance temperature detector.

20. The controller according to claim 14 wherein the instructions are executable without operator interface.