DETECTION OF AN AC INPUT PHASE-LOSS ON A MULTI-PHASE AC SERVO DRIVE

• US 20080180087A1
• Filed: 01/31/2007
• Published: 07/31/2008
• Est. Priority Date: 01/31/2007
• Status: Active Grant

• Current Assignee: Rockwell Automation Technologies Incorporated (Rockwell Automation, Inc.)
• Original Assignee: Rockwell Automation Technologies Incorporated (Rockwell Automation, Inc.)
• Inventors: Schmidt, Robert Harris, Pankau, Jeffery J.
• Granted Patent: US 7,480,124 B2
• Time in Patent Office: Days
• US Class Current: 324/76.74
• CPC Class Codes: H02H 3/253 for multiphase applications, e.g. phase interruption

Abstract

Systems and methods that detect a phase loss condition in a three-phase electrical power source are presented. The system includes a detection component that measures and/or monitors a magnitude and frequency of a voltage of a power source, and a controller component that compares measured and/or monitored voltage characteristics to characteristics associated with phase loss.

Claims

1. A system that detects phase loss comprising:

a detection component that measures a magnitude and a frequency of a three-phase voltage; and

a firmware controller component that compares the magnitude and the frequency to predetermined voltage characteristics indicative of a phase loss.

2. The system of claim 1, the detection component further comprises a magnitude component that measures the magnitude of the three-phase voltage.

3. The system of claim 1, the detection component further comprises a frequency component that measures the frequency of the three-phase voltage.

4. The system of claim 1, the detection component is comprised of hardware, software, and/or firmware components.

5. The system of claim 1, comprising a thee-phase rectifier component to convert three-phase AC power to DC power.

6. The system of claim 5, comprising a DC bus that supplies DC power to one or more three-phase load devices.

7. The system of claim 6, the detection component monitors a magnitude and frequency of a ripple voltage associated with the converted three-phase DC voltage.

8. The system of claim 7, the controller component compares the magnitude and frequency of ripple voltage associated with the converted three-phase DC voltage to a magnitude and ripple voltage frequency associated with phase loss.

9. The system of claim 7, further comprising an analog to digital converter that converts the ripple voltage into digital form for analysis by the controller component.

11. The system of claim 8, the ripple voltage frequency associated with phase loss is substantially equal to 120Hz.

10. (canceled)

12. A method to detect a phase loss condition in a three-phase power supply comprising:

measuring a magnitude and frequency of a three-phase voltage of a power source; and

comparing the measured magnitude and frequency to a magnitude and frequency associated with phase loss, the comparison performed wholly by firmware.

13. The method of claim 12, comprising initiating a shut down procedure for a device deriving power from the power source.

15. The method of claim 12, the measuring is performed by hardware, software, or firmware components, or combinations thereof.

16. The method of claim 12, comprising indicating a phase loss condition has occurred.

14. (canceled)

17. A method to detect a phase loss condition in a three-phase electrical system comprising:

monitoring a magnitude and frequency of a ripple voltage associated with a DC bus; and

comparing the monitored magnitude and frequency to a magnitude and frequency associated with phase loss, the comparison performed wholly by firmware.

18. The method of claim 17, wherein monitoring the magnitude and frequency of the ripple voltage further comprises converting an analog ripple voltage signal to a digital ripple voltage signal.

19. The method of claim 18, wherein comparing the monitored magnitude and frequency further comprises applying a filter to the digital ripple voltage signal to isolate voltage components caused by single-phase operation from those caused by standard operation of a three-phase load device.

20. The method of claim 19, further comprising comparing the filtered ripple voltage magnitude to a predetermined threshold.

21. The method of claim 20, further comprising taking a load device offline if the filtered ripple voltage is greater than a predetermined threshold for longer than a threshold period of time.

22. The method of claim 17, further comprising posting a fault that indicates a phase loss has occurred if the monitored magnitude and frequency is substantially equal to a magnitude and frequency associated with phase loss.

23. The method of claim 21, the load device is a three-phase motor drive.

24. The method of claim 19, the filter is a band-pass filter, or a Fast Fourier Transform filter, or combinations thereof.

25. A system that detects phase loss in an industrial network comprising:

supplying means for supplying predetermined operation requirements to a motor drive system;

means for measuring voltage characteristics of a DC voltage bus in conjunction with the supplying means; and

firmware comparing means that compares the voltage characteristics of the DC voltage bus to predetermined voltage characteristics associated with a phase loss.

26. The system of claim 25, further comprising a means for pointing to a source of data based upon requirements of a requester.

27. The system of claim 25, further comprising a means for display that displays processes of the industrial network.