Orthogonal field magnetic DC current sensor

• US 20060097713A1
• Filed: 11/09/2004
• Published: 05/11/2006
• Est. Priority Date: 11/09/2004
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Brandt, Randy L.
• Granted Patent: US 7,176,672 B2
• Time in Patent Office: Days
• US Class Current: 324/117.00H
• CPC Class Codes: G01R 15/185 with compensation or feedback windings or interacting coils, e.g. 0-flux sensors using galvano-magnetic field sensors G01R15/20; conversion of DC into AC using transductors G01R19/20
• CPC Class Codes: G01R 19/20 using transductors , i.e. a magnetic core transducer the saturation of which is cyclically reversed by an AC source on the secondary side

Abstract

A DC current sensor has a core comprising a magnetically permeable material. A permeability measurement winding is formed around at least a portion of the core. The core is placed within a magnetic field of a conductor such that measurement of a permeability of the core via the permeability measurement winding facilitates determination of current flow through the conductor.

Claims

1. A DC current sensor comprising:

a core comprising a magnetically permeable material;

a permeability measurement winding formed around at least a portion of the core; and

wherein the core is placed within a magnetic field of a conductor such that measurement of a permeability of the core via the permeability measurement winding facilitates determination of current flow through the conductor.

2. The DC current sensor as recited in claim 1, wherein the core comprises soft iron.

3. The DC current sensor as recited in claim 1, wherein the core is generally planar in configuration.

4. The DC current sensor as recited in claim 1, wherein the core is configured so as to define a plate.

5. The DC current sensor as recited in claim 1, further comprising a flux concentrator configured to concentrate magnetic flux proximate the conductor onto the core.

6. The DC current sensor as recited in claim 1, further comprising a generally toroidal flux concentrator disposed proximate the conductor and configured to concentrate magnetic flux proximate the conductor onto the core.

7. The DC current sensor as recited in claim 1, further comprising a flux concentrator configured to concentrate magnetic flux proximate the conductor onto the core, the flux concentrator comprising a gap within which at least a portion of the core is disposed.

8. The DC current sensor as recited in claim 1, further comprising:

a voltage driver in electrical communication with the permeability measurement winding for applying a voltage thereto; and

a current measurement circuit in electrical communication with the permeability measurement winding for measuring current flow therethrough in response to application of the voltage.

9. The DC current sensor as recited in claim 1, further comprising a temperature compensation winding formed about at least a portion of the core.

10. The DC current sensor as recited in claim 1, further comprising a temperature compensation winding formed about at least a portion of the core, the temperature compensation winding being oriented approximately orthogonally with respect to the permeability measurement winding.

11. The DC current sensor as recited in claim 1, further comprising a temperature sensor formed upon the core.

12. The DC current sensor as recited in claim 1, further comprising:

a temperature compensation winding formed about at least a portion of the core;

a temperature sensor formed upon the core;

a temperature measurement circuit in electrical communication with the temperature sensor; and

a current source in electrical communication with the temperature measurement circuit and the temperature compensation winding, the current source being configured to receive a current control signal from the temperature measurement circuit and to provide current to the temperature compensation winding in response to the current control signal, so as to mitigate variations in a permeability of the core due to temperature variations thereof.

13. A DC current sensor comprising:

a core;

a permeability measurement winding formed about the core;

a voltage driver for applying a voltage to the permeability measurement winding; and

a current measurement circuit for measuring current flow though the permeability measurement winding.

14. A method of measuring DC current, the method comprising measuring an inductance of an inductor, wherein the inductance is dependent upon the DC current.

15. A method of measuring DC current in a conductor, the method comprising:

placing a core proximate the conductor such that a permeability of the core is affected by magnetic flux produced by current flow through the conductor; and

determining a permeability of the core.

16. The method of claim 15, wherein placing a core proximate a conductor comprises placing a soft iron core proximate the conductor.

17. The method of claim 15, wherein placing a core proximate a conductor comprises placing a generally planar core proximate the conductor.

18. The method of claim 15, wherein placing a core proximate a conductor comprises placing a core having a permeability measurement winding formed about a portion thereof proximate the conductor, the permeability measurement winding being oriented such that a magnetic field produced thereby is approximately orthogonal with respect to a magnetic field of the conductor.

19. The method of claim 15, wherein placing a core proximate a conductor comprises placing a core having a plurality of generally orthogonal windings formed thereabout proximate the conductor, the windings being oriented such that magnetic fields produced thereby are approximately orthogonal with respect to a magnetic field of the conductor, one of the windings varying an inductance of the core in a manner that compensates for temperature variations thereof.

20. The method of claim 15, further comprising placing a flux concentrator proximate the conductor, the core being placed at least partially within a gap of the flux concentrator.

21. The method of claim 15, further comprising placing a magnetically permeable toroid proximate the conductor, the core being placed at least partially within a gap of the toroid.

22. The method of claim 15, wherein determining a permeability of the core comprises applying a voltage to a winding of the core and determining a current flowing through the winding.

23. The method of claim 15, further comprising measuring a temperature of the core and varying the permeability of the core in a manner that tends to mitigate permeability variations therein due to temperature variations thereof.

24. The method of claim 15, further comprising measuring a temperature of the core and varying the permeability of the core via a temperature compensation winding in a manner that tends to mitigate permeability variations therein due to temperature variations thereof.