JPH0682486A - Current detector - Google Patents

Abstract

PURPOSE:To enable current detection of high accuracy by reducing the influence of an external magnetic field on an electronic circuit board. CONSTITUTION:A current detector comprises an electronic circuit board 6 surrounded by the electrical closed loop 9 of a metallic plate. Since the metallic plate forms a closed loop, when downward magnetic flux is applied to the inside of the metallic plate 9, electromagnetic induction occurs and an induction electromotive force is generated in the direction for preventing change in the magnetic flux within the metallic plate 9 and an induced current flows rightwards. Since the magnetic flux within the metallic plate 9 is canceled out, the influence of an external magnetic field on the portion of the electronic circuit board 6 shielded by the metallic plate can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current detector in which an electric current is caused to flow in a ferromagnetic core and a magnetic flux generated at this time is detected by using a magnetic sensitive element, and in particular, an electric current which is improved in influence of an external magnetic field It concerns a detector.

[0002]

2. Description of the Related Art The structure of a conventional current detector will be described with reference to FIG. FIG. 5 shows, for example, the actual exploitation 64-
It is a figure which shows the external appearance side surface of the conventional current detector shown by 8668 gazette.

In FIG. 5, 1 is a magnetic gap, 2 is a ferromagnetic core, 3 is a magnetic sensing element such as a Hall element,
Reference numeral 4 is a magnetic flux, 5 is a primary conductor through which a current to be detected flows, 6 is an electronic circuit board, 7 is an output terminal, and 8 is a circuit component.

Next, the operation of the above-mentioned conventional current detector will be described. When the primary conductor 5 through which the detected current If flows is penetrated through the ferromagnetic core 2, a magnetic flux 4 proportional to the detected current If is generated in the magnetic gap 1 provided in the magnetic path of the ferromagnetic core 2. , The magnetic sensitive element 3 arranged in the magnetic gap 1 is penetrated.

Since the magnetic sensing element 3 converts this magnetic flux 4 into an electric output proportional to the strength of the magnetic flux, if this is taken out to the output terminal 7 by the electronic circuit board 6, as a result, the detected current If is obtained. A proportional output is obtained.

[0006]

In the conventional current detector as described above, when a conductor for flowing a large current (including a conductor for passing a current to be detected) or a magnet is arranged near the current detector. However, there is a problem that the electronic circuit board 6 is affected by the magnetic field and outputs an unnecessary output to the outside.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to reduce the influence of an external magnetic field on an electronic circuit board, which in turn makes it possible to detect a current with high accuracy. The purpose is to obtain a detector.

[0008]

A current detector according to claim 1 of the present invention comprises a ferromagnetic core having a magnetic gap provided in a part of an annular magnetic path, and a magnetic sensing element arranged in the magnetic gap. An element, a primary conductor through which a current to be detected flows, and an electronic circuit board having means for processing the output from the magnetic sensing element, based on the output of the magnetic sensing element sensitive to the magnetic flux generated in the magnetic gap In the current detector for detecting the value of the current flowing through the primary conductor, at least a part of the electronic circuit board is arranged in an electrically closed loop.

According to a second aspect of the present invention, a current detector has a ferromagnetic core having a magnetic gap in a part of an annular magnetic path, and a magnetic sensing element arranged in the magnetic gap.
The primary conductor includes a primary conductor through which a current to be detected flows and an electronic circuit board having means for processing an output from the magnetic sensing element, and the primary conductor is based on an output of the magnetic sensing element sensitive to a magnetic flux generated in the magnetic gap. A current detector for detecting a value of a current flowing through the electronic circuit board, wherein at least a part of the electronic circuit board is disposed in a first electrically closed loop, and
The electrically closed loop of is arranged in a second electrically closed loop having a different opening direction.

[0010]

In the current detector according to the first aspect of the present invention, at least a part of the electronic circuit board having means for processing the output of the magnetic sensing element is arranged in an electrically closed loop, so The influence of the magnetic field can be improved.

In the current detector according to the second aspect of the present invention, the electronic circuit board portion arranged in the electric closed loop is arranged in another electric closed loop. Since the opening directions of the electrically closed loops are arranged so as to be different from each other, the direction of the external magnetic field that can be effectively shielded is widened, and the shielding effect can be further enhanced.

[0012]

【Example】

Example 1. The configuration of the first embodiment of the present invention will be described with reference to FIG. First Embodiment FIG. 1 is a diagram showing a first embodiment of the present invention.

In FIG. 1, 1 is a magnetic gap, 2 is a ferromagnetic core, 3 is a magnetic sensing element such as a Hall element, 4 is a magnetic flux, and 5 is a primary conductor through which a detected current flows. Also, 6
Is an electronic circuit board, 7 is an output terminal, and 8 is an electronic circuit component.

Reference numeral 9 is an electrically closed loop, and its constituent material includes a metal plate, an electric wire, a conductive paint and the like.
In the first embodiment, a metal plate is used as an electrically closed loop, and almost the entire electronic circuit board 6 is covered.

In the current detector constructed as described above, the operating principle is exactly the same as the conventional technique.

The principle of shielding the external magnetic field will be described with reference to FIG. FIG. 2 is a detailed view of the electronic circuit board 6 and the metal plate portion in FIG. 1, in which 10a and 10b are magnetic fluxes penetrating the inside of the metal plate by an external magnetic field, and 11a and 11b are induced currents.

Now, when a magnetic flux is applied to the metal plate in the direction of 10a, since this metal plate is a closed loop, an induced electromotive force is generated in a direction to prevent the change of the magnetic flux in the metal plate by the electromagnetic induction action. , 11a, an induced current flows. The magnetic flux in the metal plate is canceled by this induced current, and the influence of the external magnetic field on the portion of the electronic circuit board 6 shielded by the metal plate can be improved.

Similarly, when a magnetic flux is applied in the direction of 10b, an induced current flows in the direction of 11b and the magnetic flux in the metal plate is canceled, so that the influence of the external magnetic field on the electronic circuit board 6 is improved. You can

Further, as shown in FIG. 2, the direction of the external magnetic field which can be effectively shielded by the electrically closed loop 9 is a direction perpendicular to the opening of the electrically closed loop 9. Therefore, the influence of the external magnetic field can be improved more efficiently by considering the arrangement of the electric closed loop 9 including the arrangement of the electronic circuit board 6 depending on the installation conditions of the current detector and the surrounding conditions.

The first embodiment of the present invention, as described above,
The electronic circuit board 6 is surrounded by an electrically closed loop 9 of a metal plate. Now, when a magnetic flux is applied to the metal plate 9 in the downward direction in the figure, the metal plate 9 is in a closed loop. Occurs, an induced current flows to the right in the figure. Therefore, the magnetic flux in the metal plate 9 is canceled, and the influence of the external magnetic field on the portion of the electronic circuit board 6 shielded by the metal plate can be improved. Similarly, when a magnetic flux is applied upward in the figure, an induced current flows leftward in the figure, and the influence of the external magnetic field can be improved.

Example 2. In the first embodiment described above, the electronic circuit board 6 is provided with the electric closed loop 9 almost entirely. However, as shown in FIG. 3, only the portion of the electronic circuit board 6 that is easily affected by the external magnetic field is shown. It goes without saying that the same effect can be expected by providing the electrically closed loop 9A.

Example 3. FIG. 4 is a diagram showing a third embodiment of the present invention. In the third embodiment, the electrically closed loop 9 configured as in the first embodiment is arranged in another electrically closed loop 9B, and two electrically closed loops 9,
9B are arranged so that the directions of the openings are different from each other, and the electronic circuit board 6 is arranged therein. With such a configuration, the direction of the external magnetic field that can be effectively shielded by the electrically closed loops 9 and 9B is widened, and the shielding effect can be further enhanced.

[0023]

As described above, according to the present invention, a ferromagnetic core having a magnetic gap in a part of an annular magnetic path, a magnetic sensing element arranged in the magnetic gap, and a detected current flow. A primary conductor and an electronic circuit board having a means for processing the output from the magnetic sensitive element are provided, and a current value flowing in the primary conductor is determined based on the output of the magnetic sensitive element sensitive to the magnetic flux generated in the magnetic gap. In the current detector for detection, since at least a part of the electronic circuit board is arranged in the electrically closed loop, it is possible to eliminate the influence of the external magnetic field.

The present invention, as explained above,
A ferromagnetic core in which a magnetic gap is provided in a part of the annular magnetic path, a magnetic sensitive element arranged in the magnetic gap, a primary conductor through which a current to be detected flows, and an output from the magnetic sensitive element are processed. An electronic circuit board having means, wherein at least one of the electronic circuit boards is a current detector for detecting a value of a current flowing through the primary conductor based on an output of the magnetic sensing element sensitive to a magnetic flux generated in the magnetic gap. Since the part is arranged in the first electric closed loop and in the second electric closed loop having an opening direction different from that of the first electric closed loop, the influence of the external magnetic field is exerted over a wide range. It has the effect of being eliminated.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a state of operation of the first embodiment of the present invention.

FIG. 3 is a perspective view showing a second embodiment of the present invention.

FIG. 4 is a diagram showing Embodiment 3 of the present invention.

FIG. 5 is a diagram showing a conventional current detector.

[Explanation of symbols]

 1 Magnetic Gap 2 Ferromagnetic Core 3 Magnetic Sensitive Element 5 Primary Conductor 6 Electronic Circuit Board 9 Electrically Closed Loop of Metal Plate 9A Electrically Closed Loop of Metal Plate 9B Electrically Closed Loop of Metal Plate

Claims (2)

[Claims] 1. A ferromagnetic core in which a magnetic gap is provided in a part of an annular magnetic path, a magnetic sensitive element arranged in the magnetic gap, a primary conductor through which a current to be detected flows, and the magnetic sensitive element. An electronic circuit board having a means for processing the output of the magnetic sensor, the current detector for detecting a value of a current flowing through the primary conductor based on an output of the magnetic sensing element sensitive to a magnetic flux generated in the magnetic gap, A current detector, wherein at least a part of the circuit board is arranged in an electrically closed loop. 2. A ferromagnetic core having a magnetic gap provided in a part of an annular magnetic path, a magnetic sensitive element arranged in the magnetic gap, a primary conductor through which a current to be detected flows, and the magnetic sensitive element. An electronic circuit board having a means for processing the output of the magnetic sensor, the current detector for detecting a value of a current flowing through the primary conductor based on an output of the magnetic sensing element sensitive to a magnetic flux generated in the magnetic gap, At least a portion of the circuit board is disposed in the first electrically closed loop and has a second opening direction different from that of the first electrically closed loop.
A current detector characterized by being arranged in an electrically closed loop of.