SYSTEM AND METHOD FOR MONITORING THE STATE OF HEALTH OF A POWER ELECTRONIC SYSTEM

• US 20110015881A1
• Filed: 07/14/2009
• Published: 01/20/2011
• Est. Priority Date: 07/14/2009
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Liang, Zhenxian, Chen, Chingchi, Degner, Michael W.
• Granted Patent: US 8,380,451 B2
• Time in Patent Office: Days
• US Class Current: 702/58
• CPC Class Codes: G01R 31/42 AC power supplies
• CPC Class Codes: H02P 29/64 Controlling or determining the temperature of the winding

Abstract

A system and method for monitoring the state of health of a power electronic system. Data representing an initial expected temperature of the circuit element and an initial value of an electrical parameter of the circuit element is obtained. An electrical pulse is applied to the circuit element to heat the circuit element. After the electrical pulse decays to a predetermined value, the electrical parameter of the circuit element is sensed and a subsequent value of the electrical parameter is obtained. A subsequent temperature of the circuit element is estimated based on the initial expected temperature of the circuit element, the initial and subsequent values of the electrical parameter, and the predetermined value of the electrical pulse. Based on the subsequent temperature, the signal that indicates whether the circuit element is operating as expected is generated.

Claims

1. A diagnostic method for monitoring a power electronic system having an electrical circuit element, the method comprising:

obtaining an initial expected temperature, and an initial value of an electrical parameter, of the circuit element;

applying an electrical pulse to the circuit element to increase the temperature thereof;

sensing the electrical parameter after the electrical pulse decays to a predetermined value to obtain a subsequent value of the electrical parameter;

estimating a subsequent temperature of the circuit element based on the initial expected temperature, the initial value, the subsequent value, and the predetermined value; and

generating a signal based on the subsequent temperature indicative of whether the circuit element is operating as expected.

2. The diagnostic method of claim 1 wherein the electrical pulse is a current pulse, the predetermined value is a current value, and the initial and subsequent values of the electrical parameter are voltage values.

3. The diagnostic method of claim 1 wherein the electrical pulse is a voltage pulse, the predetermined value is a voltage value, and the initial and subsequent values of the electrical parameter are current values.

4. The diagnostic method of claim 1 further including comparing the subsequent temperature to a predetermined temperature to obtain a temperature comparison and generating the signal based on the temperature comparison.

5. The diagnostic method of claim 1 further including estimating a temperature difference based on the subsequent temperature and the initial expected temperature and generating the signal based on the temperature difference.

6. The diagnostic method of claim 5 further including comparing the temperature difference to a predetermined temperature difference and generating the signal based on the comparing.

7. The diagnostic method of claim 5 further including estimating a thermal impedance of the circuit element based on the temperature difference and generating the signal based on the thermal impedance.

8. The diagnostic method of claim 7 further including obtaining an impedance comparison based on the thermal impedance of the circuit element and predetermined thermal impedance information and generating the signal based on the impedance comparison.

9. The diagnostic method of claim 7 wherein the thermal impedance of the circuit element is estimated based on an estimated power loss of circuit element at least partially due to the electrical pulse.

10. The diagnostic method of claim 9 further including sensing the electrical parameter of the circuit element after the electrical pulse rises to a predetermined upper value to obtain a corresponding upper value of the electrical parameter and estimating the estimated power loss based on the corresponding upper value and the predetermined upper value.

11. The diagnostic method of claim 1 further including accessing the data representing the initial expected temperature of the circuit element and the initial value of the electrical parameter from a computer-readable storage medium for estimating the subsequent temperature.

12. The diagnostic method of claim 1 further including controlling the circuit element based on the signal to change the temperature of the circuit element.

13. The diagnostic method of claim 1 wherein the electrical pulse has a width between 1 microsecond and 10 minutes.

14. The diagnostic method of claim 13 wherein the width is between 1 and 10 milliseconds.

15. The diagnostic method of claim 1 furthering including obtaining the initial expected temperature from a hot spot of the circuit element.

16. At least one processor-readable storage medium having processor-readable code embodied thereon for programming at least one processor to perform a method of generating a signal that indicates whether a circuit element is operating as expected, the method comprising:

obtaining an initial expected temperature, and an initial value of an electrical parameter, of the circuit element;

applying an electrical pulse to the circuit element to increase the temperature thereof;

sensing the electrical parameter after the electrical pulse decays to a predetermined value to obtain a subsequent value of the electrical parameter;

estimating a subsequent temperature of the circuit element based on the initial expected temperature, the initial value, the subsequent value, and the predetermined value; and

generating the signal based on the subsequent temperature indicative of whether the circuit element is operating as expected.

17. The storage medium of claim 16 furthering including estimating a temperature difference based on the subsequent temperature and the initial expected temperature and generating the signal based on the temperature difference.

18. The storage medium of claim 16 furthering including estimating a thermal impedance of the circuit element based on the temperature difference and generating the signal based on the thermal impedance.

19. A system for generating a signal that indicates whether a circuit element is operating as expected, the system comprising:

a computer-readable storage medium; and

a controller in communication with the storage medium, the controller being configured to perform a method comprising;

obtaining an initial expected temperature, and an initial value of an electrical parameter, of the circuit element;

applying an electrical pulse to the circuit element to increase the temperature thereof;

sensing the electrical parameter after the electrical pulse decays to a predetermined value to obtain a subsequent value of the electrical parameter;

estimating a subsequent temperature of the circuit element based on the initial expected temperature, the initial value, the subsequent value, and the predetermined value; and

generating the signal based on the subsequent temperature indicative of whether the circuit element is operating as expected.

20. The system of claim 19 wherein the method further includes estimating a thermal impedance of the circuit element based on the subsequent temperature and generating the signal based on the thermal impedance.