device for monitoring an operation of an inductive element

• US 20150123675A1
• Filed: 11/04/2014
• Published: 05/07/2015
• Est. Priority Date: 11/05/2013
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: MARTINI, Marco, MUELLER, Bernd, GUENTHER, Uwe, MELI, Bertrand Eric, HENKEL, Frank
• Granted Patent: US 10,175,285 B2
• Time in Patent Office: Days
• US Class Current: 324/546
• CPC Class Codes: G01R 31/72 Testing of electric windings testing of transformers G01R31/62

Abstract

A device for monitoring an operation of an inductive element, includes a current-measuring device is switched in series with the inductive element. The device is configured to ascertain a first time-discrete and value-discrete signal, which characterizes a current flowing through the current-measuring device; to ascertain a second time-discrete and value-discrete signal, which characterizes a current flowing through the current-measuring device and has a predefinable time shift in relation to the first signal; and to infer the presence of a shunt from a comparison of the first signal with the second signal. Also described is a method for monitoring the operation of the inductive element.

Claims

1. A device for monitoring an operation of an inductive element, a current-measuring device being connected in series with the inductive element, comprising:

a determining arrangement to ascertain a first time-discrete and value-discrete signal, which characterizes a current flowing through the current-measuring device, to ascertain a second time-discrete and value-discrete signal, which characterizes a current flowing through the current-measuring device and has a predefinable time shift in relation to the first signal, and to infer the presence of a shunt from a comparison of the first signal with the second signal.

2. The device of claim 1, wherein the determining arrangement is configured to ascertain the first signal in that a voltage drop that arises in the current-measuring device and characterizes the current flowing through the current-measuring device, is ascertained and converted into the first signal by an A/D converter.

3. The device of claim 1, wherein the determining arrangement is configured to obtain the second signal from the first signal through a delay operation.

4. The device of claim 1, wherein the determining arrangement is configured to perform the following within the framework of the comparison:

determining a signal that characterizes a difference between the first signal and the second signal; and

comparing the signal that characterizes the difference between the first signal and the second signal and/or a signal derived therefrom, with a corresponding predefinable threshold value.

5. The device of claim 4, wherein the determining arrangement is configured to subject the signal that characterizes the difference between the first signal and the second signal and/or a signal derived therefrom to filtering, decimation and/or a sampling-rate reduction.

6. The device of claim 1, wherein the determining arrangement is configured to perform the following within the framework of the comparison:

subjecting the first signal and/or the second signal to filtering and/or decimation and/or a sampling-rate reduction to obtain a filtered and/or sampling-rate-reduced first signal and/or a filtered and/or sampling-rate-reduced second signal;

determining a difference between the filtered and/or sampling-rate-reduced first signal and the filtered and/or sampling-rate-reduced second signal, through a difference calculation, to obtain a signal that characterizes the difference between the filtered and/or sampling-rate-reduced first signal and the filtered and/or scanning-rate reduced second signal; and

comparing the signal that characterizes the difference between the filtered and/or sampling-rate-reduced first signal and the filtered and/or sampling-rate-reduced second signal and/or a signal derived therefrom, with a corresponding predefinable threshold value.

7. The device of claim 6, wherein the filtered and/or sampling-rate-reduced first signal and/or the filtered and/or sampling-rate-reduced second signal and/or the signal that characterizes the difference between the filtered and/or sampling-rate-reduced first signal and the filtered and/or sampling-rate-reduced second signal have/has a lower sampling rate than the first signal and/or the second signal.

8. The device of claim 6, wherein the filtered and/or sampling-rate-reduced first signal and/or the filtered and/or sampling-rate-reduced second signal and/or the signal that characterizes the difference between the filtered and/or sampling-rate-reduced first signal and the filtered and/or sampling-rate-reduced second signal have/has a different value resolution than the first signal and/or the second signal.

19. The device of claim 1, wherein the determining arrangement is configured to ascertain the first signal in that a voltage drop that arises in the current-measuring device and characterizes the current flowing through the current-measuring device, is ascertained and converted into the first signal by a sigma-delta A/D converter.

20. The device of claim 1, wherein the determining arrangement is configured to perform the following within the framework of the comparison:

determining a signal that characterizes a difference between the first signal and the second signal, by a difference calculation of the signals; and

comparing the signal that characterizes the difference between the first signal and the second signal and/or a signal derived therefrom, with a corresponding predefinable threshold value.

9. A method for monitoring an operation of an inductive element, a current-measuring device being connected in series with the inductive element, the method comprising:

ascertaining a first time-discrete and value-discrete signal, which characterizes a current flowing through the current measuring device;

ascertaining a second time-discrete and value-discrete signal, which characterizes a current flowing through the current-measuring device and which has a predefinable time shift in relation to the first signal; and

comparing the first signal with the second signal to infer the presence of a shunt.

10. The method of claim 9, wherein the first signal is ascertained in that a voltage drop that arises in the current-measuring device and characterizes the current flowing through the current-measuring device is ascertained and converted into the first signal by an A/D converter.

11. The method of claim 9, wherein the second signal is formed from the first signal through a delay operation.

12. The method of claim 9, wherein the following are performed within the framework of the comparison:

forming a signal that characterizes a difference between the first signal and the second signal; and

comparing the signal that characterizes the difference between the first signal and the second signal and/or a signal derived therefrom, with a corresponding predefinable threshold value.

13. The method of claim 12, wherein the signal that characterizes the difference between the first signal and the second signal and/or a signal derived therefrom are/is subjected to filtering, decimation and/or a sampling-rate reduction.

14. The method of claim 9, wherein the following are performed within the framework of the comparison:

subjecting the first signal and/or the second signal to filtering, decimation and/or a sampling-rate reduction to obtain a filtered and/or sampling-rate-reduced first signal and/or a filtered and/or sampling-rate-reduced second signal;

calculating a difference between the filtered and/or sampling-rate-reduced first signal and the filtered and/or sampling-rate-reduced second signal, by subtraction, to obtain a signal that characterizes the difference between the filtered and/or sampling-rate-reduced first signal and the filtered and/or sampling-rate-reduced second signal; and

comparing the signal that characterizes the difference between the filtered and/or sampling-rate-reduced first signal and the filtered and/or sampling-rate-reduced second signal and/or a signal derived therefrom, with a corresponding predefinable threshold value.

15. The method of claim 14, wherein the filtered and/or sampling-rate-reduced first signal and/or the filtered and/or sampling-rate-reduced second signal and/or the signal that characterizes the difference between the filtered and/or sampling-rate-reduced first signal and the filtered and/or sampling-rate-reduced second signal have/has a lower sampling rate than the first signal and/or the second signal.

16. The method of claim 14, wherein the filtered and/or sampling-rate-reduced first signal and/or the filtered and/or sampling-rate-reduced second signal and/or the signal that characterizes the difference between the filtered and/or sampling-rate-reduced first signal and the filtered and/or sampling-rate-reduced second signal have/has a different value resolution than the first signal and/or the second signal.

17. The method of claim 9, wherein the first signal is ascertained in that a voltage drop that arises in the current-measuring device and characterizes the current flowing through the current-measuring device is ascertained and converted into the first signal by a sigma-delta A/D converter.

18. The method of claim 9, wherein the following are performed within the framework of the comparison:

forming a signal that characterizes a difference between the first signal and the second signal, by a difference calculation of the signals; and

comparing the signal that characterizes the difference between the first signal and the second signal and/or a signal derived therefrom, with a corresponding predefinable threshold value.