Sensing properties of switching devices using back EMF measurements

Patent metadata

Field	Value
Publication number	US-11651918-B2
Application number	US-202016902899-A
Country	US
Kind code	B2
Filing date	Jun 16, 2020
Priority date	Jun 16, 2020
Publication date	May 16, 2023
Grant date	May 16, 2023

Abstract

A system may include a switching device. The switching device may include an armature that may move between a first position that electrically couples the armature to a first contact and a second position that electrically couples the armature to a second contact. The switching device may also include a coil that may receive a voltage that magnetizes a core, thereby causing the armature to move from the first position to the second position. The system may also include a control system that may monitor a voltage waveform associated with the coil during an open operation of the switching device.

First claim

The invention claimed is:

1. A system, comprising:
a switching device, comprising:
an armature configured to move between a first position that electrically couples the armature to a first contact and a second position that electrically couples the armature to a second contact;
a coil configured receive a voltage configured to magnetize a core, thereby causing the armature to move from the first position to the second position; and
a control system configured to:
receive initial coil voltage data corresponding to a voltage waveform associated with the coil during a first open operation of the switching device;
receive updated coil voltage data corresponding to the voltage waveform associated with the coil during a second open operation of the switching device that occurs after a close operation of the switching device that occurred between the first open operation and the second open operation;
determine a change between the updated coil voltage data and the initial coil voltage data by:
determining a first difference between a first maximum value associated with the initial coil voltage data and a second maximum value associated with the updated coil voltage data during the first open operation and the second open operation, respectively; and
determining a second difference between a first minimum value associated with the initial coil voltage data and a second minimum value associated with the updated coil voltage data during the first open operation and the second open operation, respectively; and
send a notification indicative of a state of the switching device to an additional control system in response to the first difference being greater than a first threshold and the second difference being greater than a second threshold, wherein the additional control system is configured to send a control signal to an additional switching device based on the state of the switching device, wherein the control signal is configured to adjust an open time interval of the additional switching device.

2. The system of claim 1 , wherein the voltage waveform corresponds to a back electromotive force (EMF) of the coil.

3. The system of claim 1 , wherein the control system is configured to determine a state of the first contact and the second contact based on the initial coil voltage data and the updated coil voltage data.

4. The system of claim 1 , wherein the control system is configured to send the notification to a computing system in response to the first difference being greater than the first threshold or the second difference being greater than the second threshold.

5. The system of claim 3 , wherein the state of the first contact and the second contact is indicative of a weld of the first contact and the second contact.

6. The system of claim 1 , wherein the control system is configured to send one or more control signals to one or more other control systems for controlling one or more other switching devices based on the change.

7. The system of claim 6 , wherein the control system is configured to:
determine an open timing interval based on the updated coil voltage data; and
send the one or more control signals to the one or more other control systems based on the open timing interval.

8. A method, comprising:
receiving, via circuitry, initial coil voltage data corresponding to a back electromotive force (EMF) waveform associated with a coil during a first open operation of a switching device;
receiving, via the circuitry, updated coil voltage data corresponding to the back EMF waveform associated with the coil during a second open operation of the switching device that occurs after a close operation of the switching device that occurred between the first open operation and the second open operation;
determining, via the circuitry, a change between the updated coil voltage data and the initial coil voltage data by:
determining a first difference between a first maximum value associated with the initial coil voltage data and a second maximum value associated with the updated coil voltage data during the first open operation and the second open operation, respectively; and
determining a second difference between a first minimum value associated with the initial coil voltage data and a second minimum value associated with the updated coil voltage data during the first open operation and the second open operation, respectively; and
sending, via the circuitry, a notification indicative of a state of the switching device to a computing device in response to the first difference being greater than a first threshold and the second difference being greater than a second threshold, wherein the computing device is configured to send a control signal to an additional switching device based on the state of the switching device, wherein the control signal is configured to adjust an open time interval of the additional switching device.

9. The method of claim 8 , comprising:
determining whether two contacts associated with the switching device are welded together based on the updated coil voltage data; and
updating the notification based on a determination that the two contacts are welded together.

10. The method of claim 8 , comprising:
determining an open timing drift based on the change; and
send one or more control signals to one or more components based on the open timing drift.

11. The method of claim 8 , comprising determining a life expectancy of the switching device based on the change, wherein the notification is indicative of the life expectancy.

12. The method of claim 11 , wherein the life expectancy is determined based on a historical record of a second back EMF waveform for a second switching device that corresponds to the switching device.

13. The method of claim 8 , comprising:
determining, via the circuitry, an amount of wear sustained by the switching device based on the change; and
updating, via the circuitry, the notification based on the amount of wear sustained by the switching device.

14. The method of claim 8 , comprising:
determining, via the circuitry, an open timing interval of the switching device based on the updated coil voltage data; and
updating, via the circuitry, the notification based on the open timing interval, wherein the computing device is configured to send one or more control signals to one or more additional switching devices based on the open timing interval of the switching device.

15. A non-transitory computer-readable medium comprising computer-executable instructions that, when executed, are configured to cause at least one processor to perform operations comprising:
receiving initial coil voltage data corresponding to a voltage waveform associated with a coil during a first open operation of a switching device;
receiving updated coil voltage data corresponding to the voltage waveform associated with the coil during a second open operation of the switching device that occurs after a close operation of the switching device that occurred between the first open operation and the second open operation;
determining a change between the updated coil voltage data and the initial coil voltage data by:
determining a first difference between a first maximum value associated with the initial coil voltage data and a second maximum value associated with the updated coil voltage data during the first open operation and the second open operation, respectively;
determining a second difference between a first minimum value associated with the initial coil voltage data and a second minimum value associated with the updated coil voltage data during the first open opera

Assignees

• Rockwell Automation Tech Inc

Inventors

• Carlson Andrew E
• Adkins Kyle B

Classifications

• H01H47/002 Primary

  Monitoring or fail-safe circuits · CPC title