JP6032534B2 - Magnetic shield and current detector provided with the same - Google Patents

Description

  The present invention relates to a coreless current detector that is constructed by integrating a magnetic shield and a bus bar, and that is manufactured at low cost while reducing the influence of highly accurate current detection and an external magnetic field.

    There is a current detector including a square cylindrical shield member on a U-shaped conductor without requiring a substantially U-shaped or C-shaped magnetic flux collecting core having an air gap so as to surround the current line to be measured. (For example, refer to Patent Document 1).

JP 2008-102116 A

  However, the cylindrical shield member made of a soft magnetic material installed so as to cover the U-shaped portion of the U-shaped conductor described in Patent Document 1 is affected by the magnetic field of the straight conductor connected to the U-shaped conductor. Therefore, there is a problem that it is difficult to reduce the cost because the shield member has to be thick in order to reduce the influence of an external magnetic field.

  In addition, there is a possibility that current measurement accuracy may be hindered by the influence of a magnetic field generated by a straight conductor connected to the U-shaped conductor.

  The current detector of the present invention is a magnetic shield provided with a bent U-shaped conductor and a branch made of a soft magnetic material, a magnetic detection device for detecting a magnetic field generated by the U-shaped conductor, and a signal of the magnetic detection device And a processing circuit unit.

  The magnetic shield is provided so as to cover a U-shaped conductor bent into a U-shape.

  Further, the magnetic shield has branches in at least two directions including a bending direction of a linear conductor extending in a current input / output direction from a conductor bent into a U shape.

  A magnetic detection device for detecting magnetism is provided in a space formed by a substantially parallel portion of a bent U-shaped conductor.

  As described above, according to the present invention, branch portions are provided in at least two directions including a U-shaped conductor bent into a U-shape and a bending direction of a linear conductor extending from the U-shaped conductor in the current input / output direction. In addition, a magnetic detection device is provided in a space formed by a substantially parallel portion of the U-shaped conductor, thereby reducing the influence of a magnetic field generated by a straight conductor extending from the U-shaped conductor in the current input / output direction. In addition, there is an effect that current detection can be performed with high accuracy.

  Further, the magnetic shield provided with the branch portion also has an effect of reducing the influence of a magnetic field generated outside without degrading highly accurate current detection performance.

  In addition, the magnetic shield provided with the branch portion can realize current detection with high accuracy even with a thin magnetic material, so that the cost can be reduced.

  Furthermore, the current detector having a plurality of phases by the magnetic shield having the branch portion reduces the mutual magnetic interference with the adjacent phase, thereby reducing the interval between the respective phases without degrading the highly accurate current detection performance. be able to. As a result, the current detector having a plurality of phases can be reduced in size, which also has an effect of reducing the cost.

It is a perspective view which shows the current detector by Embodiment 1 which concerns on this invention. It is AA '(XZ plane) sectional drawing in FIG. 1 of this invention. It is BB '(XY plane) sectional drawing in FIG. 1 of this invention. It is a perspective view which shows the electric current detector provided with the several phase by Embodiment 2 which concerns on this invention. It is a perspective view showing a current detector provided with a plurality of phases by Embodiment 3 concerning the present invention. It is BB '(XY plane) sectional drawing of FIG. 1 which shows the current detector by Embodiment 4 which concerns on this invention.

Embodiment 1. FIG.
FIG. 1 is a perspective view showing a current detector 1 according to Embodiment 1 of the present invention.
2 is a cross-sectional view taken along the line AA ′ (XZ plane) in FIG. 1 of the present invention.
In FIG. 2, the current detector 1 includes a U-shaped conductor 3 bent into a U-shape and a conductor 2 including a linear conductor 4 extending from the U-shaped conductor 3 in the current input / output direction. In addition, the magnetic detection device 5 is provided in a space formed by the substantially parallel portions 3 a and 3 b of the U-shaped conductor 3. Furthermore, the magnetic detection device 5 is provided with a substrate 6 positioned so as to be disposed at substantially the center of a space formed by the substantially parallel portions 3a and 3b of the U-shaped conductor 3, and the substrate 6 further includes the magnetic detection device. A processing circuit unit 7 for processing the signal 5 is also arranged.
The current detector 1 includes a magnetic shield 8 made of a soft magnetic material so as to cover the U-shaped conductor 3 of the conductor 2 and the magnetic detection device 5, and the magnetic shield 8 is in the direction of the straight conductor 4 of the conductor 2. The branch portion 9 is bent in at least two directions including.

  The magnetic detection device 5 is arranged at the approximate center of the space formed by the substantially parallel portions 3a and 3b of the U-shaped conductor 3, so that the magnetic field to be measured is a combination of the magnetic fields generated by the approximately parallel portions 3a and 3b. A sufficient measurement magnetic field can be obtained without requiring a general magnetic collecting core. This magnetic detection device may use a Hall element or a magnetoresistive effect element such as AMR or GMR.

  The magnetic shield 8 is arranged to suppress a magnetic field generated outside the current detector 1, is made of a soft magnetic material, and is arranged so as to cover the U-shaped conductor 3 and the magnetic detection device 5. . Further, the branch portion 9 constituting the magnetic shield 8 has an effect of shielding the magnetic field generated from the straight conductor 4 of the conductor 2, and the magnetic detection device 5 generates a magnetic field generated in the substantially parallel portions 3 a and 3 b of the U-shaped conductor 3. This has the effect of improving the measurement accuracy.

3 is a cross-sectional view taken along the line BB ′ (XY plane) in FIG. 1 of the present invention.
In FIG. 3, the current detector 1 includes a U-shaped conductor bent into a U-shape and a conductor 2 composed of a straight conductor 4 extending from the U-shaped conductor in the current input / output direction. In addition, a magnetic detection device 5 having a maximum detection sensitivity with a magnetic field in the Y direction is provided in a space formed by the substantially parallel portions 3a and 3b of the U-shaped conductor. Furthermore, the magnetic detection device 5 is disposed in the approximate center of the space formed by the substantially parallel portions 3 a and 3 b of the U-shaped conductor 3.
The current detector 1 includes a magnetic shield 8 made of a soft magnetic material so as to cover the U-shaped conductor 3 of the conductor 2 and the magnetic detection device 5, and the magnetic shield 8 is in the direction of the straight conductor 4 of the conductor 2. The branch portion 9 is bent in at least two directions including.

  In the magnetic shield 8, the substantially parallel portions 3a and 3b of the U-shaped conductor disposed in the magnetic shield 8 are magnetized by the generated magnetic fields 10a and 10b acting in opposite directions to cancel the generated magnetic field. Although the magnetic saturation of the shield 8 can be suppressed, the magnetic field generated by the straight conductor 4 acts on the surfaces 8a and 8b of the magnetic shield 8 when there is no branch portion 9 of the magnetic shield 8, and the magnetic shield 8 is likely to be saturated. It becomes difficult to reduce the thickness.

  However, since the magnetic field generated by the straight conductor 4 is shielded by the branch portion 9 of the magnetic shield 8 and the influence on the surfaces 8a and 8b can be suppressed, the magnetic shield 8 can be thinned and the cost can be reduced.

  Further, even if the magnetic shield 8 is thinned, the magnetic shield 8 is not magnetically saturated with the magnetic field generated by the substantially parallel portions 3a, 3b and the straight conductor 4, so that the magnetic shielding ability is not reduced and the magnetic field generated outside is affected. On the other hand, it has a sufficient reduction effect.

Embodiment 2. FIG.
FIG. 4 is a perspective view showing a current detector having a plurality of phases according to Embodiment 2 of the present invention.
Similar to the first embodiment, a U-shaped conductor 3 bent into a U-shape and a conductor 2 including a linear conductor 4 extending from the U-shaped conductor 3 in the current input / output direction are provided. In addition, the magnetic detection device 5 is provided in a space formed by the substantially parallel portions 3 a and 3 b of the U-shaped conductor 3. Furthermore, the magnetic detection device 5 is disposed in the approximate center of the space formed by the substantially parallel portions 3 a and 3 b of the U-shaped conductor 3.
Further, a magnetic shield 8 made of a soft magnetic material is provided so as to cover the U-shaped conductor 3 of the conductor 2 and the magnetic detection device 5, and the magnetic shield 8 includes at least two directions including the direction of the straight conductor 4 of the conductor 2. The A phase 11 of the current detector, the B phase 12 of the current detector, and the C phase 13 of the current detector are provided.
Further, the linear conductors 4, 14, 15 of each phase are arranged substantially in parallel, and the magnetic detection device of each phase has a sensitivity direction perpendicular to the linear conductors 4, 14, 15 of each phase, and Located on position 16.

The A phase 11 of the current detector can reduce the influence of magnetic fields generated by the magnetic shield 8 from the B phase 12 of the current detector and the C phase 13 of the current detector, which are adjacent phases. The magnetic field generated by its own straight conductor 4 due to the shielding effect has the effect of reducing the influence on the B phase 12 of the current detector of the adjacent phase and the C phase 13 of the current detector, thereby reducing the mutual magnetic interference of each phase. , Current measurement accuracy is improved.

  Furthermore, the mutual magnetic interference of each said phase falls, and the space | interval between each phase can be narrowed. As a result, the current detector having a plurality of phases can be reduced in size, and the cost can be reduced.

Embodiment 3. FIG.
FIG. 5 is a perspective view showing a current detector having a plurality of phases according to Embodiment 3 of the present invention.
As shown in FIG. 5, the A phase 11 of the current detector, the B phase 12 of the current detector, and the C phase 13 of the current detector are arranged so that the linear conductors 4, 14, 15 of each phase are arranged substantially in parallel. In order to further reduce the magnetic interference, each phase of the magnetic detection device has a sensitivity direction perpendicular to the linear conductors 4, 14, 15 of each phase and is staggered like positions 17, 18, 19 of the magnetic detection device. You may arrange.

Embodiment 4 FIG.
6 is a cross-sectional view taken along the line BB ′ (XY plane) of FIG. 1 showing a current detector according to Embodiment 4 of the present invention.
In FIG. 6, the current detector 1 includes a U-shaped conductor bent into a U-shape and a conductor 2 composed of a linear conductor 4 extending from the U-shaped conductor in the current input / output direction. In addition, a magnetic detection device 5 having a maximum detection sensitivity with a magnetic field facing each other in the X direction is provided in a space formed by the substantially parallel portions 3a and 3b of the U-shaped conductor. Furthermore, the magnetic detection device 5 is disposed in the approximate center of the space formed by the substantially parallel portions 3 a and 3 b of the U-shaped conductor 3.
Moreover, the current detector 1 includes a magnetic shield 8 made of a soft magnetic material so as to cover the U-shaped conductor of the conductor 2 and the magnetic detection device 5, and the magnetic shield 8 extends in the direction of the straight conductor 4 of the conductor 2. The branch part 9 bent in at least two directions is included.

  Further, the magnetic device is disposed at an end portion in the open direction of a space formed by the substantially parallel portions 3a and 3b of the U-shaped conductor, and the magnetic fields 10a and 10b generated at the substantially parallel portions 3a and 3b are opposed to each other. The detection sensitivity is maximized.

  Furthermore, since the magnetic device 5 has a maximum detection sensitivity due to the magnetic fields facing each other, it cancels out the magnetic field 20 generated outside and becomes insensitive to the magnetic field 21 generated outside. There is an effect that the magnetic field generated by the external magnetic field can be further reduced.

DESCRIPTION OF SYMBOLS 1 ... Current detector, 2 ... Conductor, 3 ... U-shaped conductor, 4, 14, 15 ... Linear conductor, 5 ... Magnetic detection device, 6 ... Substrate, 7 ...・ Processing circuit part, 8 ... magnetic shield, 9 ... branch part, 10a, 10b, 20, 21 ... magnetic field, 11 ... A phase of current detector, 12 ... current detector B phase, 13 ... C phase of current detector, 16, 17, 18, 19 ... position of magnetic detection device

Claims (3)

A U-shaped conductor (3) bent into a U-shape and a conductor (2) consisting of a linear conductor (4) extending in the current input / output direction from the U-shaped conductor (3), A space in which the magnetic detection device (5) is provided in a space formed by the substantially parallel portions (3a, 3b), and the magnetic detection device (5) is formed by the substantially parallel portions (3a, 3b) of the U-shaped conductor (3). The substrate (6) is positioned so as to be disposed in the approximate center of the substrate, and the substrate (6) further includes a processing circuit unit (7) for processing a signal of the magnetic detection device (5).
A magnetic shield (8) made of a soft magnetic material is provided so as to cover the U-shaped conductor (3) of the conductor (2) and the magnetic detection device (5), and the magnetic shield (8) is a conductor (2). A current detector comprising a branch portion (9) bent in at least two directions including the direction of the straight conductor (4). 2. The current detector according to claim 1 , further comprising a magnetic detection device at a substantially center of a space formed by the substantially parallel portions (3 a) and (3 b) of the U-shaped conductor (3) of the current detector. . Magnetic detection device (5) in which the detection sensitivity is maximized by a magnetic field facing each other at the end in the open direction of the space formed by the substantially parallel portions (3a) and (3b) of the U-shaped conductor (3) of the current detector. The current detector according to claim 1 , further comprising:

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