AIR-COOLED POWER ELECTRONICS SERVICE ALGORITHM

• US 20090164150A1
• Filed: 02/12/2008
• Published: 06/25/2009
• Est. Priority Date: 12/21/2007
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Van Maanen, Keith D.
• Granted Patent: US 8,042,993 B2
• Time in Patent Office: Days
• US Class Current: 702/60
• CPC Class Codes: G01K 7/42 Circuits effecting compensation of thermal inertia; Circuits for predicting the stationary value of a temperature

Abstract

A method for determining the thermal efficiency of a heat sink for an electrical component includes determining an estimated temperature of the heat sink, determining an actual temperature of the heat sink, and determining a thermal efficiency of the heat sink based on a comparison of the estimated temperature of the heat sink to the actual temperature of the heat sink. A related diagnostic system is provided.

Claims

1. A diagnostic system comprising:

a first temperature sensor configured to measure an actual temperature of a heat sink in thermal contact with an electrical component;

a cooling air mass in contact with said heat sink;

a second temperature sensor configured to measure a temperature of said cooling air mass; and

a control module that determines an estimated temperature of said heat sink based on said temperature of said cooling air mass, wherein said estimated temperature is compared to said actual temperature to determine whether said heat sink is functioning properly.

2. The diagnostic system of claim 1, wherein said first temperature sensor is disposed on a first surface of said heat sink adjacent said electrical device.

3. The diagnostic system of claim 1 wherein said control module determines said estimated temperature based on an electrical power of said electrical component.

4. The diagnostic system of claim 3 wherein said control module determines said electrical power based on at least one of an electrical current of said electrical component, a voltage of said electrical component, and a temperature of said electrical component.

5. The diagnostic system of claim 1 wherein said control module:

compares a difference between said estimated temperature and said actual temperature to a predetermined value; and

generates a status signal indicating whether or not said heat sink is functioning properly based on said difference.

6. The diagnostic system of claim 1 further comprising a fan for moving a quantity of said cooling air mass across said heat sink.

7. The diagnostic system of claim 6 wherein said control module determines said estimated temperature based on said quantity of said cooling air mass.

8. The diagnostic system of claim 7 wherein said control module generates a power signal for controlling a speed of said fan and said quantity of said cooling air mass is determined based on said speed.

9. A method of determining a thermal efficiency of a heat sink for an electrical component, comprising:

determining an estimated temperature of said heat sink;

determining an actual temperature of said heat sink; and

determining said thermal efficiency of said heat sink based on a comparison of said estimated temperature and said actual temperature.

10. The method of claim 9, further comprising:

generating a status signal indicative of said thermal efficiency of said heat sink based on whether said estimated temperature is within a predetermined range of said actual temperature.

11. The method of claim 10, wherein said status signal indicates a need to service said heat sink when said estimated temperature is not within said predetermined range of said actual temperature.

12. The method of claim 9 further comprising:

determining an average power of said electrical component during one of N time intervals, wherein N is an integer greater than or equal to 1;

determining an average temperature of a cooling air during said one of N time intervals;

determining an average mass air flow of said cooling air during said one of N time intervals; and

determining said estimated temperature at said one of N time intervals based on said average power of said electrical component, said average temperature of said cooling air flow, and said average mass air flow of said cooling air.

13. The method of claim 12 wherein N is a predetermined value.

14. The method of claim 12 wherein a duration of said one of said N time intervals is different from durations of others of said N time intervals.

15. The method of claim 12 wherein durations of each of said N time intervals are predetermined.

16. The method of claim 12 wherein two of said N time intervals are separated by a time delay.

17. The method of claim 16 wherein a duration of said time delay is zero.

18. The method of claim 12 further comprising determining said estimated temperature at an i^th of said N time intervals based on said estimated temperature at an (i−

1)^th of said N time intervals where 1<

i≦

N.

19. The method of claim 9, wherein determining said estimated temperature of said heat sink includes determining an average power of said electrical component, determining an average temperature of a cooling air flow associated with said heat sink, and determining an average mass air flow of said cooling air flow.

20. The method of claim 19 wherein said average power, said average temperature, said average mass air flow and said estimated temperature are determined at at least one of N time intervals, N being an integer greater than or equal to 1.

21. The method of claim 9 further comprising:

comparing a difference between said estimated temperature of said heat sink and said actual temperature of said heat sink to a predetermined value; and

generating a status signal associated with said heat sink based on said difference.

22. A method of determining a thermal efficiency of a heat sink for an electrical component comprising:

determining an estimated temperature of said heat sink at N time intervals, wherein N is an integer that is greater than 1 and said estimated temperature at an i^th of said N time intervals is based on said estimated temperature at an (i−

1)^th of said N time intervals where 1<

i≦

N;

measuring an actual temperature of said heat sink at said N time intervals;

calculating a difference between said estimated temperature and said actual temperature at said N time intervals;

generating a status signal associated with said thermal efficiency of said heat sink based on a comparison of said difference to a predetermined value.

23. The method of claim 22 wherein N is a predetermined value.

24. The method of claim 22 wherein durations of each of said N time intervals are predetermined.

25. The method of claim 22 wherein there are no time delays between each of said N time intervals.