JPH0232577A - Current detection device - Google Patents

Abstract

PURPOSE:To obtain a stable output with a simplified and miniaturized structure by forming a spiral-shaped magnetic thin film on a non-magnetic round bar, and applying torsion stress to the round bar to drive a non-detection current, and thereby providing an AC magnetic field to generate pulse voltage. CONSTITUTION:In a detector element 1, a Fe-base amorphous magnetic film 3 is formed on the circumferential surface of a non-magnetic round bar into a spiral shape slanted about 45 with respect to a bar axis. Conductor thin films 4 are formed on opposite ends of the thin film 3 and connected to the thin film 3. Torsion stress is exerted on the round bar 2 circumferentially of the same. Once a current I to be detected is driven through a magnetizing coil 7 and an AC magnetic field is applied to the round bar 2 longitudinally of the thin film 3 by the shift of a magnetic wall, and pulse voltage is generated from the opposite ends of the thin film 3 owing to electric resistance of the thin film 3. The pulse voltage which depends on the magnitude and frequency of the current to be detected allows the magnitude of the current to be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a current detection device for detecting alternating current flowing in a conductor.

[Conventional technology]

2. Description of the Related Art Conventionally, a device for detecting an alternating current flowing through a conductor uses a magnetic sensor or a detection coil to detect a magnetic field created by the current. The outline of this configuration is to wind a coil around an iron core, pass a magnetic flux through this iron core, and install a magnetic sensor in the air gap provided in the iron core. Detects current from the voltage generated in the coil. Recently, however, a non-magnetic cylinder surrounding a conductor is being considered, in which soft magnetic ribbons such as Fe-based amorphous magnetic ribbons are spirally wound with an insulating layer interposed between them.

= I am n. When a tensile stress is applied to this soft magnetic ribbon, when the direction of magnetization of the magnetic ribbon is reversed by a single alternating current flowing through the conductor, a gusset effect occurs and a pulse voltage is generated. Since this voltage depends on the current in the conductor, the current can be detected from this voltage.

[Problem to be solved by the invention]

In a configuration in which a magnetic sensor or a detection coil detects a magnetic field created by an electric current, an iron core, a magnetic sensor, a detection coil, and the like are required, making it difficult to miniaturize the device. In addition, in a configuration in which a magnetic ribbon is wound around a non-magnetic cylinder, it is difficult to fix the cylinder and the magnetic ribbon, and when the voltage generated at both ends of the mother ribbon is led to the outside, lead wires must be soldered. As a result, magnetic ribbons, especially Fe-based amorphous magnetic ribbons that are commonly used, suffer from deterioration in magnetism or thermal distortion, resulting in unstable output. There have been problems such as difficulty in increasing the amount.

An object of the present invention is to provide a current detection fc device that is easy to manufacture, can be miniaturized, has stable output, and can increase output.

[Means to solve the problem]

In order to solve the above-mentioned problems, the current detection device of the present invention
An iB material was formed in a spiral shape as a thin film around the periphery, and a conductive thin film was formed on both ends of this mother thin film, which was made up of a connected non-magnetic round bar, and a torsional stress was applied in the circumferential direction of this non-magnetic round bar. A device comprising a detection element, a magnetized coil wound around the detection element to flow a current to be detected, and a detector connected between the conductor thin films to detect voltage, and detects the current based on an instruction from the detector. shall be. Note that sensitivity increases when a plurality of detection elements are connected in a zigzag pattern so as to receive the same magnetic field effect at the same time, and the magnetic thin films of adjacent detection elements are connected in series with a conductive thin film. Further, if the non-magnetic round bar is used as a non-magnetic conductor through which the current to be detected flows, the magnetizing coil can be omitted.

[Effect]

A soft magnetic material that tends to cause rapid domain wall movement is formed from a vapor state into a thin film around a non-magnetic round bar.

That is, it is formed by vapor deposition, sputtering, talling, ion grating, etc., and when torsional stress is applied in the circumferential direction of the round bar, tensile stress is generated in this direction. Therefore, if the magnetic thin film is a magnetic material with positive magnetostriction,
The direction of this tensile stress becomes the axis of easy magnetization, and when the magnetization is reversed by the alternating magnetic field, the magnetic flux in the direction of the magnetic field by the coil, that is, the length direction of the round bar, becomes dominant, so a current flows in the longitudinal direction of the magnetic thin film, and this longitudinal direction A sensing element is obtained in which a voltage is generated at both ends. This voltage depends on the strength of the magnetic field of this magnetization coil (magnitude of coil current) and the AC frequency, if the magnetic thin film is magnetized with a magnetization coil that is wound around the detection element and flows the current to be detected. Therefore, conductor thin film terminals are constructed on both ends of this magnetic thin film to derive this voltage and detect it with a detector.

In other words, when using an Fe-based amorphous magnetic material as the best material to obtain the Machiushi effect, it should be noted that this material is sensitive to heat, and it should be made into a magnetic thin film instead of a magnetic ribbon.
A conductive thin film is formed on both ends of the membrane.

Connect it and use it as a terminal. In addition, unlike a magnetic ribbon, the magnetic thin film formed on the circumferential surface of the round bar does not have magnetic anisotropy if it is only treated with evaporated N, so in order to provide this, torsional stress is applied to the round bar to create a tensile stress on the surface. Using stress.

In this type of configuration, multiple detection elements are prepared, and when the detection elements with different winding directions of the magnetic thin film are connected in a zigzag pattern in a crosswise direction, each detection element within the same magnetized coil receives the same magnetic field effect. Since the voltages generated by each detection element are added together, ! Flow sensitivity improves.

Note that the non-magnetic round bar is a non-magnetic conductor through which the current to be detected flows.
When magnetizing a magnetic thin film with this non-maternal conductor, the magnetizing coil can be omitted. However, in this case, it is necessary that the magnetic thin films of the plurality of detection elements are all spirally wound in the same direction.

[Embodiment] FIGS. 1 to 6 show embodiments of the current detection device according to the present invention. In FIG. 1, the detection element 1 has an Fe-based amorphous magnetic thin film 3 formed in a vapor state in a spiral shape at an angle of about 45° to the rod axis on the surface of a non-magnetic circle $2, as shown in FIG. . Further, a conductor thin film 4 is formed on both ends of the magnetic thin film 3 and is connected to the magnetic thin film 3. A torsional stress δ is applied to the non-magnetic round bar 2 in the circumferential direction. Both conductive thin films 4 are led out through lead wires 5 and connected to a detector 6 for detecting voltage. A magnetized coil 7 is wound around the detection element 1 to allow a current to be detected to flow therethrough.

Note that the torsional stress δ is more effective when the round bar 2 is twisted while applying a tensile stress in the longitudinal direction. In such a detection element, the magnetic thin film 3 has a tensile stress δt approximately 45° to the longitudinal direction. Since this is given, this direction becomes the axis of easy magnetization.

Here, when a current to be detected ■ is applied to the magnetizing coil 7 and an alternating current magnetic field is applied in the longitudinal direction of the round bar 2, the magnetization vector generated in the magnetic thin film 3 is directed in a direction perpendicular to the longitudinal direction of the magnetic thin film 3 (
In order to generate a component φl in the width direction), a current is generated in the longitudinal direction of the magnetic thin film 3 due to domain wall movement, and a pulse voltage E is generated from both ends of the magnetic thin film 3 due to the electrical resistance of the magnetic thin film 3 as shown in FIG. do. The level 615 of this pulse voltage E
It depends on the flux φl and the moving speed of the domain wall. That is, since the pulse voltage E changes depending on the magnitude and frequency of the current to be detected, the magnitude of the current to be detected can be detected from this pulse voltage.

Next, in FIG. 4, the detection elements 1 shown in FIG. 2 are connected in a zigzag pattern, and the magnetic thin films 3a to 3e of the respective elements 13 to 1e are connected in series by the conductor thin films 4b to 4e, and the detection elements 1a to 1e are connected in series.
is inserted into the inside of the magnetizing coil 71, and the conductive thin films 4ae4f at both ends are led out with lead wires 5 and connected to the detector 6. Here, the spiral winding directions of the magnetic thin films of adjacent elements among the elements 1a to 1e are reversed, so that each of the magnetic thin films 33 to 3e is affected by the magnetic field in the same way, and the generated pulse voltage E is All are made to participate. Traditional φ
Since the function of generating the voltage E by l is the same as that described with reference to FIG. 1, this explanation will be omitted.

In this case, since the pulse voltage E theoretically increases by the number of elements 1a to 1e, the current sensitivity improves accordingly.

Figure 5 shows an embodiment different from Figures 1 and 4.
The detection element 11 is constructed by using the nonmagnetic circle 412 as a nonmagnetic conductor 8 such as a copper wire. The other configurations of the Fe-based amorphous magnetic thin film and the conductive thin film are the same as those shown in Figure @4, so their explanation will be omitted. A current is applied to the non-magnetic conductor 8. At this time, the magnetic field due to the current is applied to the non-magnetic conductor 8.
is generated in the circumferential direction and acts on the magnetic thin film 3. Therefore, the direction of the magnetic field on the magnetic thin film 3 differs by exactly 900 degrees from the embodiments shown in FIGS. The effect on the magnetic thin film 3 is almost the same, and the detected current I is equal to the conductor weight 1g1 provided at both ends of the magnetic thin film 3.
4 is detected by a detector 6 via a lead wire 5 connected to the lead wire 5 .

FIG. 6 shows an embodiment different from the above three embodiments, in which each nonmagnetic conductor 8a to 8e is coated with Fe-based amorphous magnetic thin films 33 to 8e.
Detecting elements 11a to 11ie in which 3e is formed in a spiral shape are connected in a zigzag shape, and the magnetic thin film 33 of each element 8a to 8e is connected in a zigzag manner.
3e are connected in series through conductive thin films 4b to 4e, and thin films 4a and 4f at both ends of the series magnetic thin films 3a to 3e are connected to a detector 6 through a lead wire 5. Here, the adjacent elements of each magnetic thin film 3a to 3e are different from the case of FIG. 1 is broken.

In this case, for example, the magnetic field that element 11a receives is element LLa
Not only due to the current flowing in the
It is also affected by the current flowing through 1e, but this effect is small.

In this way, the current sensitivity is improved over that shown in FIG. 5 by approximately the number of detection elements 1a to 1e.

〔Effect of the invention〕

The current detecting device according to the present invention has a magnetic thin film spirally formed on a non-magnetic round part or a non-magnetic conductor as the main part for detecting current, and twisting stress is applied to this round bar or crosspiece to form a magnetic thin film. When a tensile stress is applied diagonally to the length direction and an alternating magnetic field is applied to this magnetic thin film, a pulse voltage that depends on the strength of the magnetic field and the moving speed of the domain wall is generated at both ends of the magnetic thin film, so this alternating magnetic field is applied to the magnetizing coil. Alternatively, this current can be detected if it is generated by a current to be detected passed through a conductor. In addition, since conductor thin films are formed as terminals at both ends of this magnetic thin film, a material such as an Fe-based amorphous magnetic thin film, which tends to cause rapid domain wall movement but is susceptible to thermal deterioration, can be used as the magnetic material, increasing detection sensitivity. I can do it. In addition, it becomes easy to connect the respective mother thin films lσ in series with conductive thin films, which is highly effective in increasing current sensitivity and downsizing.

[Brief explanation of the drawing]

1 to 6 show an embodiment of a current detection device according to the present invention, FIG. 1 is a wiring diagram showing one embodiment, and FIG. 2 shows a detection element used in the embodiment shown in FIG. 1. Fig. 3 is a waveform diagram showing the relationship between the magnetic flux of the component force generated in the magnetic thin film and the pulse voltage, Fig. 4 is a wiring diagram showing an embodiment different from Fig. 1, and Figs. Figure 6 is Figure 1 or Figure 4, respectively.
It is a wiring diagram showing an example different from the figure. 1, la, 1e, 11.11a to 11e: detection element, 2
: Non-magnetic round bar, 3.3a-3e: Amorphous magnetic thin film, 4.4a-4f: 24-body thin film, 6: Detector, 7, 7
1: a-coil, 8: non-magnetic conductor.

Claims (1)

[Claims] 1) A non-magnetic round bar with a magnetic material spirally formed around it as a thin film, and a conductive thin film formed on both ends of the magnetic thin film and connected to each other in the circumferential direction of the non-magnetic round bar. The detector comprises a detection element to which torsional stress is applied, a magnetized coil wound around the detection element to flow a current to be detected, and a detector connected between the two conductor thin films to detect a voltage. A current detection device characterized by detecting current from an instruction. 2) In the current detection device according to claim 1, the plurality of detection elements are configured to receive the same magnetic field effect at the same time and are connected in a zigzag shape, and the magnetic thin films of adjacent detection elements are connected in series with a conductive thin film. A current detection device characterized by: 3) The current detection device according to claim 1 or 2, wherein the non-magnetic round bar is a non-magnetic conductor through which a current to be detected flows, and a magnetized coil is omitted.