Measuring electrical current flowing through a conductor

• US 7,321,227 B2
• Filed: 04/12/2006
• Issued: 01/22/2008
• Est. Priority Date: 04/13/2005
• Status: Active Grant

• Current Assignee: Huettinger Elektronik GmbH + Company KG (TRUMPF SE + Co. KG)
• Original Assignee: Huettinger Elektronik GmbH + Company KG (TRUMPF SE + Co. KG)
• Inventors: Fritsch, Christian, Mann, Ekkehard
• Primary Examiner(s): Nguyen; Vinh P.
• Application Number:
  US11/279,443
• Publication Number:
  US 20060232265A1
• Time in Patent Office: 650 Days
• Field of Search: 324117 R-117 H, 324126-127, 324/142, 336/84.R, 702/60, 702/85, 505/842, 505/845
• US Class Current: 324/142
• CPC Class Codes: G01R 1/18 Screening arrangements against electric or magnetic fields, e.g. against earth's field
• CPC Class Codes: G01R 15/181 using coils without a magnetic core, e.g. Rogowski coils
• CPC Class Codes: G01R 19/0061 Measuring currents of particle-beams, currents from electron multipliers, photocurrents, ion currents; Measuring in plasmas

Abstract

A current measurement device for measuring an electrical current, in particular in a contactless manner, in a current-carrying conductor, using a coil arrangement having a coil conductor and a circuit connected to the coil conductor, the coil arrangement being surrounded at least in portions by a coil shield. The coil shield and the circuit are connected to a ground potential independently of each other. The measurement accuracy is thereby increased.

Claims

1. An electric current sensor comprising

a coil assembly with a coil conductor;

a circuit connected to the coil conductor;

a coil shield at least partially surrounding at least a portion of the coil assembly;

a conductive ground member; and

a cooling body arranged to cool the coil shield;

wherein the coil shield and the circuit are connected to the conductive ground member at respective, spaced apart ground connections.

2. The current sensor of claim 1, wherein the conductive ground member is a common ground plate to which the coil shield and circuit are independently connected.

3. The current sensor of claim 1, wherein the conductive ground member comprises two interconnected ground plates, the coil shield and circuit each connected to a respective one of the ground plates.

4. The current sensor of claim 1, wherein the circuit includes a circuit shield connected to the ground member, the circuit being arranged inside the circuit shield.

5. The current sensor of claim 1, wherein the coil assembly is substantially circular.

6. The current sensor of claim 1, wherein the coil shield is substantially circular.

7. The current sensor of claim 6, wherein the coil shield is formed as a hollow body toroid.

8. The current sensor of claim 7, wherein the toroid is substantially rectangular in cross-section.

9. The current sensor of claim 7, wherein the toroid is partially open.

10. The current sensor of claim 1, wherein the coil conductor is wrapped about a non-ferromagnetic carrier.

11. The current sensor of claim 10, wherein the coil assembly comprises a Rogowski coil.

12. The current sensor of claim 1, wherein the circuit comprises an impedance connected across the coil.

13. The current sensor of claim 12, wherein the impedance is a resistance.

14. The current sensor of claim 1, wherein the circuit has at least one measurement connection configured for connection to an evaluation device.

15. A method of measuring electrical current, the method comprising

placing a current sensor about an electrical conductor in a contact-free manner, the current sensor comprising

a coil assembly with a coil conductor;

a circuit connected to the coil conductor;

a conductive ground member;

a coil shield at least partially surrounding at least a portion of the coil assembly and

a cooling body arranged to cool the coil shield;

wherein the coil shield and the circuit are connected to the conductive ground member at respective, spaced apart ground connections;

flowing an electrical current along the conductor; and

measuring the flowing current with the sensor.

16. An electric current sensor comprising

a coil assembly with a coil conductor;

a circuit connected to the coil conductor;

a conductive circuit shield arranged to shield the circuit;

a conductive coil shield at least partially surrounding at least a portion of the coil assembly;

a conductive ground member; and

a cooling body arranged to cool the coil shield;

wherein the coil shield and the circuit shield are connected to the conductive ground member at respective, spaced apart ground connections.

17. The current sensor of claim 16, wherein the conductive ground member is a common ground plate to which the coil shield and the circuit are independently connected.

18. The current sensor of claim 16, wherein the conductive ground member comprises two interconnected ground plates, the coil shield and the circuit each connected to a respective one of the ground plates.

19. The current sensor of claim 16, wherein the circuit includes a circuit shield connected to the ground member, the circuit being arranged inside the circuit shield.

20. The current sensor of claim 16, wherein the coil assembly is substantially circular.

21. The current sensor of claim 16, wherein the coil shield is substantially circular.

22. The current sensor of claim 16, wherein the coil conductor is wrapped about a non-ferromagnetic carrier.

23. The current sensor of claim 16, wherein the circuit comprises an impedance connected across the coil.

24. The current sensor of claim 16, wherein the circuit has at least one measurement connection configured for connection to an evaluation device.