Winding fault detection system

• US 7,834,573 B2
• Filed: 07/31/2007
• Issued: 11/16/2010
• Est. Priority Date: 07/31/2007
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Sychra, Robert R., Lindsey, Robert W.
• Primary Examiner(s): Benson; Walter
• Assistant Examiner(s): GLASS, ERICK DAVID
• Application Number:
  US11/882,242
• Publication Number:
  US 20090033357A1
• Time in Patent Office: 1,204 Days
• Field of Search: 318/490, 318/434, 361/33
• US Class Current: 318/490
• CPC Class Codes: G01R 31/343 in operation
• CPC Class Codes: G01R 31/346 Testing of armature or field windings
• CPC Class Codes: H02H 7/0855 avoiding response to transient overloads, e.g. during starting

Abstract

A control system is disclosed. The control system has an electric machine coupled to provide power to or receive power from a DC bus and a controller in communication with the electric machine and the DC bus. The controller is configured to receive a voltage from the DC bus, compare the voltage from the DC bus to a characteristic indicative of a fault of at least one winding of the electric machine, and take a precaution based on the comparison.

Claims

1. A control system, comprising:

an electric machine coupled to provide power to or receive power from a DC bus;

a controller in communication with the electric machine and the DC bus, the controller being configured to;

receive an indication of a measured voltage of the DC bus;

average the measured voltage of the DC bus over a period of time;

determine a difference between the average voltage of the DC bus and the measured voltage of the DC bus;

determine, based on the difference between the average voltage of the DC bus and the measured voltage of the DC bus, whether to indicate a fault of at least one winding of the electric machine; and

when it is determined to indicate a fault of at least one winding of the electric machine, generate a signal to initiate a precaution.

2. The control system of claim 1, wherein the electric machine includes one of a motor, a generator, and a motor/generator.

3. The control system of claim 1, wherein the controller is configured to determine whether to indicate a fault of at least one winding the electric machine based on whether a difference between the measured voltage of the DC bus and the average voltage of the DC bus is more than a predetermined voltage.

4. The control system of claim 1, wherein the fault includes a short of the at least one winding to ground.

5. The control system of claim 1, wherein initiating a precaution includes at least one of activating an alarm, powering down the electric machine, or interrupting a circuit.

6. A method for detecting a winding fault, comprising:

providing power to or receiving power from an electric machine via a DC bus;

receiving an indication of a measured voltage of the DC bus;

averaging the measured voltage of the DC bus over a period of time;

determining a difference between the average voltage of the DC bus and the measured voltage of the DC bus;

indicating a fault of at least one winding of the electric machine based on the determined difference between the average voltage of the DC bus and the measured voltage of the DC bus; and

responsive to an indication of a fault of at least one winding of the electric machine, generating a signal to initiate a precaution.

7. The method of claim 6, wherein the electric machine includes one of a motor, a generator, and a motor/generator.

8. The method of claim 6, wherein a fault of at least one winding of the electric machine is indicated when the difference between the average voltage of the DC bus and the measured voltage of the DC bus is more than a predetermined voltage.

9. The method of claim 6, wherein the fault includes a short of the at least one winding to ground.

10. The method of claim 6, wherein initiating a precaution includes at least one of activating an alarm, powering down the electric machine, or interrupting a circuit.

11. A machine, comprising:

a combustion engine configured to power operations of the machine;

a motor arranged to move the machine;

a generator coupled to receive a mechanical power input from the combustion engine, and provide electrical power output through a DC bus to the motor; and

a controller in communication with the generator, the motor, and the DC bus, the controller being configured to;

receive an indication of a measured voltage of the DC bus;

average the measured voltage of the DC bus over a period of time;

determine a difference between the average voltage of the DC bus and the measured voltage of the DC bus;

determine whether to indicate a winding fault of at least one of the motor and the generator based on the determined difference between the average voltage of the DC bus and the measured voltage of the DC bus; and

generate a signal to initiate a precaution responsive to a determination to indicate a winding fault of at least one of the motor and the generator.

12. The machine of claim 11, wherein the controller is configured to determine whether to indicate a winding fault based on whether the difference between the measured voltage of the DC bus and the averaged voltage of the DC bus is more than a predetermined voltage.

13. The machine of claim 11, wherein the fault includes a short of the at least one winding to ground.

14. The machine of claim 11, wherein initiating a precaution includes at least one of activating an alarm, powering down the electric machine, or interrupting a circuit.

15. A method for detecting a winding fault, comprising:

providing power to or receiving power from an electric machine via a DC bus;

receiving an indication of a measured voltage of the DC bus;

averaging the measured voltage of the DC bus over a period of time;

identifying a fault of at least one winding of the electric machine based on;

(1) the measured voltage of the DC bus, and

(2) the average voltage of the DC bus; and

generating a signal to initiate a precaution when a fault of at least one winding of the electric machine is identified.

16. A fault detection system for detecting a winding fault in an electric machine providing power to or receiving power from a DC bus, the system comprising:

an averaging unit configured to receive a measured voltage of the DC bus, and to determine an average of the measured voltage of the DC bus over a period of time;

a threshold detector configured to provide a threshold signal indicating when a difference between the average voltage of the DC bus and the measured voltage of the DC bus is greater than a threshold voltage; and

a signal processor configured to identify a fault in the winding of the electric machine based on the threshold signal, and to initiate a precaution when a fault in the winding of the electric machine is identified.

17. The fault detection system of claim 16, wherein the averaging unit is a low pass filter.