Device for measuring current

• US 20070164727A1
• Filed: 01/16/2007
• Published: 07/19/2007
• Est. Priority Date: 01/19/2006
• Status: Active Grant

• Current Assignee: Melexis Tessenderlo NV
• Original Assignee: Sentron AG (Sensinnovat BVBA)
• Inventors: Racz, Robert, Gloor, Markus, Huber, Samuel
• Granted Patent: US 7,545,136 B2
• Time in Patent Office: Days
• US Class Current: 324/142
• 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 15/202 using Hall-effect devices Hall elements in arrangements for measuring electrical power G01R21/08
• CPC Class Codes: G01R 15/207 Constructional details independent of the type of device used

Abstract

A device for measuring current comprises a magnetic field sensor (2) for measuring the magnetic field produced by a current I flowing through a current conductor (1) and a yoke (3) of a magnetic material with a relative permeability of at least 100. The magnetic field sensor (2) preferably comprises a semiconductor chip with at least one Hall element and an electronic circuit for the operation of the Hall element. Two magnetic field concentrators (7, 8) separated by an air gap (6) are arranged on a surface of the semiconductor chip such that field lines (9) of the magnetic field (see FIG. 3) that issue from the first magnetic field concentrator (7) in the vicinity of the air gap (6) and impinge on the second magnetic field concentrator (8) in the vicinity of the air gap (6) pass through the at least one Hall element. The yoke (3) consists of an oblong piece of sheet metal or a laminate of sheet metals with two ends (10, 11) that has been brought by bending into a form with which the front sides of the ends (10, 11) of the yoke (3) lie opposite each other and are separated by an air gap (14). The ends (10, 11) of the yoke (3) are tapered so that a width of the ends of the yoke is less than a width of the yoke.

Claims

1. A device for measuring current, comprising a magnetic field sensor for measuring a magnetic field produced by a current flowing through a current conductor, the magnetic field sensor encapsulated into a housing, and a yoke of a magnetic material with a relative permeability of at least 100, wherein the yoke has two ends separated by an air gap and with front sides that lie opposite each other, wherein the yoke has two sidewalls and is formed such that it borders the current conductor with the exception of the air gap completely, wherein the housing with the magnetic field sensor is placed inside the yoke and outside the air gap of the yoke, and wherein a length of the yoke measured at right angles to the current conductor and parallel to the air gap of the yoke is at least the same size as a height of the yoke measured perpendicularly to the air gap.

2. The device of claim 1, wherein the ends of the yoke are tapered.

3. The device of claim 1, wherein the ends of the yoke are enlarged or provided with a recess or are enlarged and provided with a recess.

4. The device of claim 1, wherein the magnetic field sensor comprises a semiconductor chip with at least one Hall element, wherein two magnetic field concentrators separated by a further air gap are arranged on a surface of the semiconductor chip, wherein field lines of the magnetic field that issue from the first magnetic field concentrator in the vicinity of the air gap and impinge on the second magnetic field concentrator in the vicinity of the air gap pass through the at least one Hall element.

5. The device of claim 2, wherein the magnetic field sensor comprises a semiconductor chip with at least one Hall element, wherein two magnetic field concentrators separated by a further air gap are arranged on a surface of the semiconductor chip, wherein field lines of the magnetic field that issue from the first magnetic field concentrator in the vicinity of the air gap and impinge on the second magnetic field concentrator in the vicinity of the air gap pass through the at least one Hall element.

6. The device of claim 3, wherein the magnetic field sensor comprises a semiconductor chip with at least one Hall element, wherein two magnetic field concentrators separated by a further air gap are arranged on a surface of the semiconductor chip, wherein field lines of the magnetic field that issue from the first magnetic field concentrator in the vicinity of the air gap and impinge on the second magnetic field concentrator in the vicinity of the air gap pass through the at least one Hall element.

7. The device of claim 1, wherein the magnetic field sensor is placed on the side of the current conductor facing the air gap of the yoke and that a further magnetic field sensor is placed on the side of the current conductor that does not face the air gap of the yoke.

8. The device of claim 2, wherein the magnetic field sensor is placed on the side of the current conductor facing the air gap of the yoke and that a further magnetic field sensor is placed on the side of the current conductor that does not face the air gap of the yoke.

9. The device of claim 3, wherein the magnetic field sensor is placed on the side of the current conductor facing the air gap of the yoke and that a further magnetic field sensor is placed on the side of the current conductor that does not face the air gap of the yoke.

10. The device of claim 4, wherein the magnetic field sensor is placed on the side of the current conductor facing the air gap of the yoke and that a further magnetic field sensor is placed on the side of the current conductor that does not face the air gap of the yoke.

11. The device of claim 5, wherein the magnetic field sensor is placed on the side of the current conductor facing the air gap of the yoke and that a further magnetic field sensor is placed on the side of the current conductor that does not face the air gap of the yoke.

12. The device of claim 6, wherein the magnetic field sensor is placed on the side of the current conductor facing the air gap of the yoke and that a further magnetic field sensor is placed on the side of the current conductor that does not face the air gap of the yoke.

13. The device of claim 1, further comprising an essentially u-shaped screen of a magnetic material with a relative permeability of at least 100 that borders the yoke on three sides, wherein the screen has three sections of which the middle section runs parallel to the air gap of the yoke.

14. The device of claim 2, further comprising an essentially u-shaped screen of a magnetic material with a relative permeability of at least 100 that borders the yoke on three sides, wherein the screen has three sections of which the middle section runs parallel to the air gap of the yoke.

15. The device of claim 3, further comprising an essentially u-shaped screen of a magnetic material with a relative permeability of at least 100 that borders the yoke on three sides, wherein the screen has three sections of which the middle section runs parallel to the air gap of the yoke.

16. The device of claim 4, further comprising an essentially u-shaped screen of a magnetic material with a relative permeability of at least 100 that borders the yoke on three sides, wherein the screen has three sections of which the middle section runs parallel to the air gap of the yoke.

17. The device of claim 7, further comprising an essentially u-shaped screen of a magnetic material with a relative permeability of at least 100 that borders the yoke on three sides, wherein the screen has three sections of which the middle section runs parallel to the air gap of the yoke.

18. The device of claim 13, further comprising an essentially u-shaped screen of a magnetic material with a relative permeability of at least 100 that borders the yoke on three sides, wherein the screen has three sections of which the middle section runs parallel to the air gap of the yoke.

19. A device for measuring current, comprising a magnetic field sensor for measuring a magnetic field produced by a current flowing through a current conductor, the magnetic field sensor encapsulated into a housing, and a yoke of a magnetic material with a relative permeability of at least 100, wherein the yoke has two ends separated by an air gap and with front sides that lie opposite each other, wherein the yoke has two sidewalls and is formed such that it borders the current conductor with the exception of the air gap completely, wherein the housing with the magnetic field sensor is placed inside the yoke and outside the air gap of the yoke, and wherein a length of the yoke measured at right angles to the current conductor and parallel to the air gap of the yoke is at least the same size as a height of the yoke measured perpendicularly to the air gap and wherein the magnetic field sensor is placed on the side of the current conductor that does not face the air gap of the yoke.

20. The device of claim 19, further comprising an essentially unshaped screen of a magnetic material with a relative permeability of at least 100 that borders the yoke on three sides, wherein the screen has three sections of which the middle section runs parallel to the air gap of the yoke.