ARRANGEMENT FOR THE POTENTIAL-FREE MEASUREMENT OF CURRENTS

• US 20100264905A1
• Filed: 12/18/2008
• Published: 10/21/2010
• Est. Priority Date: 12/22/2007
• Status: Active Grant

• Current Assignee: Sensitec GmbH
• Original Assignee: Sensitec GmbH
• Inventors: Schmitt, Jochen
• Granted Patent: US 8,680,856 B2
• Time in Patent Office: Days
• US Class Current: 324/126
• CPC Class Codes: G01R 15/205 using magneto-resistance devices, e.g. field plates
• CPC Class Codes: G01R 15/207 Constructional details independent of the type of device used
• CPC Class Codes: G01R 33/022 Measuring gradient
• CPC Class Codes: G01R 33/09 Magnetoresistive devices

Abstract

The invention relates to an arrangement for the potential-free measurement of current flowing in two primary conductors (13, 14) arranged in parallel in opposite directions of each other, wherein the magnetic differential field is detected by means of a differential field sensor (12). In order to reduce measuring errors, the primary conductors (13, 14) and the differential field sensor (12) are disposed between two metal parts that are configured as shield plates (1, 2) made of a highly permeable material, each having a web (3 or 6). The webs (3, 6) extend on both sides of the arrangement of the primary conductors (13, 14) substantially in the direction thereof parallel to the arrangement. At least one of the shield plates (1, 2) is configured in a U-shape in cross-sectional planes, having one pair of limbs (4, 5; 7, 8) each, which extend at a right angle in a longitudinal direction to the U-shaped cross-sectional planes. The two shield plates (1, 2) are disposed relative to each other such that at least one limp pair (4, 5; 7, 8) of one of the two shield plates (1,2) is aligned toward the other of the two shield plates (1, 2) on one of the two limbs (4, 5; 7, 8) while leaving an air gap (9, 10).

Claims

1. Arrangement for the potential-free measurement of currents flowing in two primary conductors (13, 14;

25, 26;

25′

, 26′

;

34, 35) arranged substantially in parallel, in opposite directions of each other, by detecting the magnetic differential field by means of a differential field sensor (12, 24, 24′

, 37), wherein for reducing measuring errors, said primary conductors (13, 14;

25, 26;

25′

, 26′

;

34, 35) and said (12, 24, 24′

, 37) are disposed between two metal parts,

characterized in

that the two metal parts are configurated as shield plates (1, 2;

15, 16;

15′

, 16′

;

27-30) made of highly permeable material each having a web (3 or 6, respectively), that said webs (3, 6) extend on both sides of the arrangement of the primary conductors (13, 14;

25, 26;

25′

, 26′

;

34, 35) substantially in the direction thereof parallel to the arrangement of the primary conductors (13, 14;

25, 26;

25′

, 26′

;

34, 35), that at least one of said shield plates (1, 2;

15, 16;

15′

, 16′

;

27-30) is configurated in a U-shape in cross-sectional planes having a pair of limbs (4, 5;

7, 8;

17-20;

19′

, 20′

) each of which extend at a right angle in a longitudinal direction to the U-shaped cross-sectional planes, that said two shield plates (1, 2;

15, 16;

15′

, 16′

;

27-30) are disposed relative to each other such that the at least one limb pair (4, 5;

7, 8;

17-20;

19′

, 20′

) of one of said two shield plates (1, 2;

15, 16;

15′

, 16′

;

27-30) is aligned towards the other of said two shield plates (1, 2;

15, 16;

15′

, 16′

, 27-30 while leaving one air gap each (9, 10;

21, 22;

21′

, 22′

;

39, 40) on one of said two limbs (4, 5;

7, 8;

17-20;

19′

, 20′

), and that said primary conductors (13, 14;

25, 26;

25′

, 26′

;

34, 35) extend in the longitudinal direction of said limbs (4, 5;

7, 8;

17-20;

19′

, 20′

).

2. Arrangement according to claim 1,

characterized in

that said two shield plates (1, 2;

15, 16;

27-20) are configurated with one limb pair (4, 5;

7, 8;

17-20) each between which one of said webs (3,6) each is disposed, and that said shield plates (1, 2;

15, 16;

27-30) are arranged relative to each other such that said two limb pairs (4, 5;

7, 8;

17-20) of said shield plates (1, 2;

15, 16;

27-30) are aligned toward each other while leaving one air gap (9, 10;

21, 22;

39, 40) each between two of said limbs (4, 5;

7, 8;

17-20).

3. Arrangement according to claim 1 or 2,

characterized in

that said primary conductors (13, 14;

25, 26;

25′

, 26′

;

34, 35) are substantially arranged between said limbs (4, 5;

7, 8;

17-20;

19′

20′

) of one of said two shield plates (1, 2;

15, 16;

15′

, 16′

;

27-30).

4. Arrangement according to claim 1 or 2,

characterized in

that said effective sensor plane (11, 23, 36) is disposed outside of said limbs (7, 8;

19-20) of said shield plate (2, 16, 28, 30) between which limbs (7, 8;

19-20) said primary conductors (13, 14, 25, 26, 35, 36) are arranged.

5. Arrangement according to claims 1-4,

characterized in

that said limbs (4, 5;

7, 8;

17-20) of said two shield plates (1, 2, 15, 16, 27-30) are equally long and

that said two shield plates (1, 2;

15, 16;

27-30) are symmetrically disposed relative to an effective sensor plane (11, 23, 36).

6. Arrangement according to claims 1-4,

characterized in

that said limbs (17, 18;

19, 20) of one of said shield plates (15, 16) each are equally long,

that said limb pairs (4, 5;

19, 20) of said shield plates (15, 16) have different lengths, and

that said primary conductors (25, 26) are substantially arranged between said longer limbs (19, 20) of one of said two shield plates (15, 16).

7. Arrangement according to one of claims 1-6,

characterized in

that said shield plates (1, 2;

15, 16;

15′

, 16′

;

27-30) extend in the longitudinal direction of the limbs thereof (4, 5;

7;

8;

17-20;

19′

20′

) substantially above said differential field sensor (12, 24, 24′

, 36).

8. Arrangement according to one of the foregoing claims,

characterized in

that said two parallel primary conductors (13, 14;

25, 26;

25′

, 26′

, 34, 35) constitute the limbs of a substantially U-shaped conductor unit.

9. Arrangement according to one of the claims 1-7,

characterized in

that said two parallel primary conductors (13, 14;

25, 26;

25′

26′

, 35, 36) are the to and fro conductor of an electric consuming device.

10. Arrangement according to claim 8,

characterized in

that said shield plates (1, 2;

15, 16;

15′

, 16′

;

27-30) extend in the longitudinal direction of the limbs thereof (4, 5, 7, 17-20) substantially over the length of said limbs (4, 5;

7, 8;

17-20;

19′

, 20′

) of said U-shaped conductor unit in the direction of the current.

11. Arrangement according to one of the foregoing claims,

characterized in

that said shield plates (1, 2;

15, 16;

15′

, 16′

;

27-30) consist of mumetal.

12. Arrangement according to one of claims 1-10,

characterized in

that said shield plates are electric sheets.

13. Arrangement according to one of the foregoing claims,

characterized in

that for the establishment of the magnetic differential field in the effective sensor plane (11, 23, 36) at least one soft magnetic insert part (31-33) is used which is arranged with the said two shield plates (1, 2;

15, 16;

27-30).

14. Arrangement according to claim 13,

characterized in

that the at least one insert part (31-33) is disposed between said effective sensor plane (11, 23, 36) and said primary conductors (13, 14;

25, 26;

34, 35).

15. Arrangement according to claim 14,

characterized in

that between each of said primary conductors (34, 35) and said effective sensor plane (36) one insert part each (31, or 32, respectively) is disposed.

16. Arrangement according to claim 14,

characterized in

that between said two primary conductors (34, 35) and the effective sensor plane (36) only one insert part (33) is disposed symmetrically to a middle plane (38) between said primary conductors (34, 35).

17. Arrangement according to claim 14,

characterized in

that the at least one insert part is disposed between said active sensor plane and the nearest neighboring shield plate.

18. Arrangement according to one of the foregoing claims,

characterized in

that said air gaps (39-42) are adjustable on or between, respectively, said limbs of said shield plates (27, 28;

29, 30).