JPH10253665A - Current detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a current detector in which the output of an magnetoelectric conversion element is increased and in which the detecting accuracy of a current is enhanced. SOLUTION: A magnetoelectric conversion element 3 and an amplifier circuit 5 are mounted on the surface of a circuit board 2. A through hole 6 is formed in the mounted lower part of the magnetoelectric conversion element 3 in the circuit board 2. A magnetic body 7 is inserted into the through hole 6. The circuit board 2 is sandwiched by a magnetic core 1 in such a way that the magnetoelectric conversion element 2 becomes the magnetic gap part of a magnetic path. A conductor wire 4 trough which a current to be detected flows is wound on the magnetic core 1. Both ends of the conductor wire 4 are used as input terminals of the current to be detected. Input/output terminals are attached to the circuit board 2. By this constitution, a magnetic flux density which is generated in the magnetic gap is increased, and the output of the magnetoelectric element 3 can be, increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current detector for detecting a current by flowing a current to be detected through a conductor wire wound around a magnetic core and amplifying a detection output obtained through a magnetoelectric conversion element.

[0002]

2. Description of the Related Art A conventional current detector is mounted on a magnetic core having a magnetic gap in a part around which a conductor wire for flowing a current to be detected is wound, and on a surface of a circuit board arranged in the magnetic gap. It has been constituted by a magneto-electric conversion element and a circuit component for amplifying and outputting a detection output signal from the magneto-electric conversion element.

In this current detector, a magnetic field generated in a gap in a magnetic core is detected by a magneto-electric conversion element by a detected current flowing through a conductor wire, and an electric signal output in proportion to a magnetic flux density is amplified by a circuit component to obtain a current. It was the output of the detector. The circuit components constitute an amplifier circuit including an operational amplifier, fixed passive elements, and a trimming resistor. The trimming of the trimming resistor adjusts an amplification factor and removes a residual voltage component included in a detection output of a current detector. The accuracy of the detection output was improved.

[0004]

In a conventional current detector, a current to be detected is passed through a conductor wire, a magnetic field generated in a gap in a magnetic core is detected by a magnetoelectric conversion element, and an electric signal proportional to the magnetic field intensity is generated. When outputting, even when the current to be detected is small, it is necessary to increase the circuit magnification of the subsequent amplifier circuit in order to obtain an appropriate output as a current detector. However, a device that amplifies a minute change in an electric signal generated in a magnetoelectric conversion circuit at a high circuit magnification has a problem that the detection accuracy as a current detector is poor.

Accordingly, the present invention is to enable accurate current detection.

[0006]

According to the present invention, there is provided a magnetic core provided with a magnetic gap, wherein a magnetoelectric conversion element is mounted and arranged on a surface of a circuit board in the gap of the magnetic core. A current detector comprising an amplifying circuit that amplifies a detection output signal from the magneto-electric conversion element by winding a conductor wire around a core and flowing a current to be detected, and penetrates through a lower portion of the circuit board where the magneto-electric conversion element is mounted. A hole is provided, and a magnetic body is inserted into the through hole.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to a first aspect of the present invention, there is provided a magnetic core provided with a magnetic gap, wherein a magnetoelectric conversion element is mounted on a surface of a circuit board in the gap, and a conductor wire is provided on the magnetic core. In a current detector configured by an amplifier circuit that amplifies a detection output signal from the magnetoelectric conversion element by flowing a current to be detected, a through hole is provided in a lower part of the magnetoelectric conversion element mounting on the circuit board, A magnetic material is inserted into the through hole, and a magnetic flux density generated in a magnetic gap of the magnetic core can be increased.

According to a second aspect of the present invention, there is provided the current detector according to the first aspect, wherein the through-hole has a diameter smaller than that of the magneto-electric conversion element. It can be directly mounted and connected to the board.

Further, the invention according to claim 3 of the present invention is the current detector according to claim 1 or 2, wherein the through hole has a circular shape and the shape of the magnetic material is a cylindrical shape. The same effect as that of No. 2 can be obtained.

According to a fourth aspect of the present invention, there is provided the current detector according to the first or second aspect, wherein the through hole has a rectangular shape, and the magnetic body has a rectangular parallelepiped shape. The same effect as that of No. 2 can be obtained.

A fifth aspect of the present invention is a current detector according to any one of the first to fourth aspects, wherein the magnetic body is formed of a silicon steel plate. The effect can be obtained.

According to a sixth aspect of the present invention, there is provided a current detector according to any one of the first to fourth aspects, wherein the magnetic substance is formed of a ferrite magnetic substance. The effect of can be obtained.

According to a seventh aspect of the present invention, there is provided the current detector according to any one of the first to fourth aspects, wherein the magnetic material is formed of permalloy (a compound metal of nickel and iron). The same effects as in Items 1 to 4 can be obtained.

According to an eighth aspect of the present invention, there is provided the current detector according to any one of the first to seventh aspects, wherein the outer periphery of the magnetic body is roughened, wherein the outer peripheral surface area of the magnetic body is increased. By doing so, the bonding area between the magnetic body and the circuit board can be increased, and the magnetic body and the circuit board can be firmly bonded.

According to a ninth aspect of the present invention, there is provided the current detector according to the eighth aspect, wherein the inner wall of the through hole is roughened, and the same effect as that of the eighth aspect can be obtained.

An embodiment of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, a current detector according to an embodiment of the present invention is configured such that a magnetoelectric conversion element 3 is mounted on a circuit board 2 by solder in the magnetic gap of a magnetic core 1 having a magnetic gap. A current detector is configured by an amplifier circuit 5 that amplifies a detection output signal from the magnetoelectric conversion element 3 by winding a conductor wire 4 around the magnetic core 1 and passing a current to be detected. In order to increase the output of the magneto-electric conversion element 3 mounted on the circuit board 2, a through hole 6 is provided on the circuit board 2 below the mounting of the magneto-electric conversion element 3, and the thickness of the circuit board 2 is A magnetic body 7 having substantially the same thickness as that of FIG.

Since the diameter of the through hole 6 is smaller than that of the magnetoelectric conversion element 3, the magnetoelectric conversion element 3 is not affected by the through hole 6,
It can be mounted and connected on the circuit board 2.

The shape of the through hole 6 is circular or square, and the shape of the magnetic body 7 is cylindrical or rectangular parallelepiped.

The magnetic body 7 is made of a silicon steel plate, a ferrite magnetic body or permalloy.

Although the magnetic body 7 is simply inserted into the through hole 6, the thickness of the magnetic body 7 is substantially the same as that of the through hole 6. Since the magnetoelectric conversion element 3 is fixed by soldering and the magnetic core 1 is adhered to the lower opening of the through hole 6, the magnetic substance 7 is consequently fixed in the through hole 6. I have.

Since the outer circumference of the magnetic body 7 and the inner wall of the through hole 6 are roughened, the outer circumference of the magnetic body 7 and the
Has a large surface area, so that when the magnetic body 7 and the inner wall of the through hole 6 are bonded with an adhesive, they can be firmly bonded.

That is, in the present embodiment, the magnetic material 7 can increase the magnetic flux density generated in the magnetic air gap of the magnetic core 1 and, as a result, the output of the magneto-electric conversion element 3 can be increased. Since it is not necessary to increase the circuit magnification, the accuracy of the current detector can be improved.

Reference numeral 8 shown in FIG. 2 is an input / output terminal of the current detector.

[0024]

As described above, according to the present invention, a magnetoelectric conversion element is mounted and arranged on a circuit board in the magnetic gap of the magnetic core provided with a magnetic gap, and a conductor wire is wound around the magnetic core. In a current detector configured to amplify a detection output signal from the magnetoelectric conversion element by passing a detection current by an amplifier circuit, a through hole is provided in a lower portion of the circuit board where the magnetoelectric conversion element is mounted, and the through hole is provided. A magnetic material is inserted into the magnetic core, and the magnetic flux density generated in the magnetic air gap of the magnetic core can be increased. As a result, the output of the magnetoelectric conversion element can be increased. As a result, it is not necessary to increase the circuit magnification of the amplifier circuit, so that a minute electric signal change generated in the amplifier circuit and the magnetoelectric conversion circuit does not affect the output of the current detector. As a result, The accuracy of the current detector can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention (A-
A cross section)

FIG. 2 is an external perspective view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic core 2 Circuit board 3 Magnetoelectric conversion element 4 Conductor wire 5 Amplification circuit 6 Through hole 7 Magnetic body 8 I / O terminal

Claims (9)

[Claims] A magneto-electric conversion element is mounted and arranged on a circuit board in a magnetic gap of a magnetic core having a magnetic gap, a conductor wire is wound around the magnetic core, and a current to be detected is passed through the magnetic core. In a current detector comprising an amplifier circuit for amplifying a detection output signal from a conversion element, a through-hole is provided in a lower portion of the circuit board where a magnetoelectric conversion element is mounted, and a magnetic body is inserted into the through-hole. And a current detector. 2. The current detector according to claim 1, wherein the diameter of the through hole is smaller than that of the magnetoelectric conversion element. 3. The current detector according to claim 1, wherein the through hole has a circular shape, and the magnetic body has a cylindrical shape. 4. The current detector according to claim 1, wherein the through hole has a rectangular shape, and the magnetic body has a rectangular parallelepiped shape. 5. The magnetic material according to claim 1, wherein the magnetic material is formed of a silicon steel plate.
5. The current detector according to any one of 4. 6. The current detector according to claim 1, wherein the magnetic material is formed of a ferrite magnetic material. 7. The current detector according to claim 1, wherein the magnetic body is formed of permalloy (a compound metal of nickel and iron). 8. The magnetic material according to claim 1, wherein the outer periphery of the magnetic material is a rough surface.
The current detector according to any one of the above. 9. The current detector according to claim 8, wherein the inner wall of the through hole has a rough surface.