JP2011221004A - Magnetic sensor and current sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic sensor and a current sensor which have a simple structure and are easily manufactured.SOLUTION: A magnetic sensor comprises: magnetic cores 4a and 4b having a same shape and opposed surfaces facing each other; an excitation coil 7 which is sandwiched between the opposed surfaces of the magnetic cores 4a and 4b and constituted by a first and second coil adjacent to each other; and a detection coil 6 arranged so as to surround at least a part of the magnetic cores 4a and 4b. The excitation coil 7 generates magnetic fields having components perpendicular to the opposed surfaces and opposed to each other in the first and second coils, respectively, when a current flows. The detection coil 6 is a magnetic sensor which is wound so as to generate a magnetic field therein having a component in the direction in which the first and second coils are arranged, when the current flows. Accordingly, the magnetic sensor which has a simple structure and is easily manufactured is obtained.

Description

  The present invention relates to a magnetic sensor and a current sensor that are simple in structure and easy to manufacture.

  A magnetic circuit comprising two spaced annular magnetic paths and two connecting magnetic paths connecting them, an exciting coil wound around the connecting magnetic path, and the two annular magnetic paths were wound so as to be integrally surrounded. A current sensor provided with a detection coil has been proposed (see, for example, Patent Document 1).

Japanese Patent No. 4310373

  However, the current sensor proposed in Patent Document 1 has a problem that the structure is complicated and it is difficult to manufacture.

  The present invention has been devised in view of such problems in the prior art, and an object thereof is to provide a magnetic sensor and a current sensor that are simple in structure and easy to manufacture.

  A first magnetic sensor according to the present invention is sandwiched between a pair of magnetic cores having the same shape having opposing surfaces facing each other and the pair of opposing surfaces of the pair of magnetic cores. An excitation coil comprising first and second coils arranged adjacent to each other, and a detection coil arranged to surround at least part of the pair of magnetic cores, the excitation coil Generates a magnetic field having components opposite to each other perpendicular to the opposing surface in the first and second coils when an electric current is applied. In this case, the detection coil is wound so as to generate a magnetic field having a component in the same direction as the direction in which the first and second coils are arranged.

  According to a second magnetic sensor of the present invention, in the configuration provided in the first magnetic sensor, the pair of magnetic cores are formed in an annular shape, and the circumferential direction of the ring of the pair of magnetic cores A plurality of the first and second coils are alternately arranged along the line.

  The first current sensor of the present invention includes the first magnetic sensor and a conductive path for flowing a current having a component in a direction perpendicular to the direction in which the first and second coils are arranged. It is characterized by.

  The second current sensor of the present invention includes the second magnetic sensor and a conductive path arranged so as to pass through the inside of the ring of the pair of magnetic cores. .

According to the first magnetic sensor of the present invention, since the structure of the magnetic core can be greatly simplified, a magnetic sensor that is simple in structure and easy to manufacture can be obtained.

  According to the second magnetic sensor of the present invention, the current that detects the current flowing through the conductive path is arranged at an arbitrary position inside the ring of the magnetic core so as to pass through the inside of the ring. Since it can function as a sensor, a magnetic sensor that can be used as a current sensor with a high degree of freedom during installation can be obtained.

  According to the first current sensor of the present invention, since the structure of the magnetic sensor can be simplified, a current sensor that is simple in structure and easy to manufacture can be obtained.

  According to the second current sensor of the present invention, since the conductive path can be arranged at an arbitrary position inside the ring of the magnetic core, the current having a high degree of freedom in the positional relationship between the magnetic core and the conductive path. A sensor can be obtained.

1 is an external perspective view schematically showing a magnetic sensor of a first example of an embodiment of the present invention. It is the disassembled perspective view which abbreviate | omitted the coil for a detection which shows typically the magnetic sensor shown in FIG. It is an external appearance perspective view which shows typically the current sensor of the 2nd example of embodiment of this invention. It is an external appearance perspective view which shows typically the magnetic sensor and electric current sensor of the 3rd example of embodiment of this invention. It is the disassembled perspective view which abbreviate | omitted the coil for a detection which shows typically the magnetic sensor and current sensor which are shown in FIG. It is a disassembled perspective view which shows typically the current sensor of the 4th example of embodiment of this invention. FIG. 7 is a plan view schematically showing the current sensor shown in FIG. 6.

  Hereinafter, a magnetic sensor and a current sensor of the present invention will be described in detail with reference to the accompanying drawings.

(First example of embodiment)
FIG. 1 is an external perspective view schematically showing a magnetic sensor of a first example of an embodiment of the present invention. FIG. 2 is an exploded perspective view schematically showing the magnetic sensor shown in FIG. In FIG. 2, the detection coil 6 is not shown for easy viewing.

As shown in FIGS. 1 and 2, the magnetic sensor of this example includes input terminals 3a and 3b, output terminals 2a and 2b, a pair of magnetic cores 4a and 4b, an insulating plate 5, and a detection coil. 6 and an exciting coil 7. The magnetic cores 4a and 4b have the same shape and have opposing surfaces facing each other. The exciting coil 7 includes a first coil 7a and a second coil 7b arranged so as to be adjacent to each other, and the surface of the insulating plate 5 sandwiched between a pair of opposing surfaces of the magnetic cores 4a and 4b. And is sandwiched between a pair of opposing surfaces of the magnetic cores 4a and 4b together with the insulating plate 5. When the current is passed, the exciting coil 7 is perpendicular to the first coil 7a and the second coil 7b opposite to each other (the xy plane in the figure) (in the z-axis direction in the figure) and opposite to each other. A magnetic field having the following components is generated. The detection coil 6 is arranged so as to surround a part of the pair of magnetic cores 4a, 4b, and at least a part of the pair of magnetic cores 4a, 4b is located inside the coils. It is wound around a part of the pair of magnetic cores 4a and 4b. When the current is passed, the detection coil 6 generates a magnetic field having a component in the same direction as the direction in which the first and second coils are arranged in the detection coil 6 (the x-axis direction in the figure). It is wound to generate. Further, the input terminals 3 a and 3 b are electrically connected to both ends of the exciting coil 7, and the output terminals 2 a and 2 b are electrically connected to both ends of the detection coil 6.

  In the magnetic sensor 10 of this example having such a configuration, for example, when a current flows in the direction from the input terminal 3a to the output terminal 3b, the first coil 7a has a magnetic field directed in the -z direction in the figure. And a magnetic field directed in the z direction in the figure is generated in the second coil 7b. Thereby, in the magnetic core 4a, a magnetic flux having a component in the −x direction in the figure is generated so as to go from the second coil 7b to the first coil 7a, and in the magnetic core 4b, the first core A magnetic flux having a component in the x direction in the figure is generated from the coil 7a toward the second coil 7b. Therefore, when there is an external magnetic field indicated by H in FIG. 1 and directed in the x direction in the figure, in the magnetic core 4a, the magnetic flux generated by the current flowing in the exciting coil 7 and the magnetic flux by the external magnetic field H cancel each other, In the magnetic core 4b, the magnetic flux generated by the current flowing through the exciting coil 7 and the magnetic flux generated by the external magnetic field H are intensified, but the degree of strengthening and the degree of weakening are not equal. Thus, the magnitude of the external magnetic field H can be detected.

  That is, when a current is passed, the detection coil 6 generates a magnetic field having a component in the same direction as the direction in which the first and second coils are arranged in the coil (the x direction in the figure). It is rolled up. For this reason, if there is a change in magnetic flux in the direction in which the first and second coils are arranged in the coil (the x-axis direction in the figure), an induced electromotive force is generated in the detection coil 6. When the external magnetic field H is 0, even if an alternating current is applied to both ends of the exciting coil 7, the magnetic flux in the magnetic core 4a and the magnetic flux in the magnetic core 4b cancel each other. Does not occur. However, since the change in magnetic permeability of the magnetic body accompanying the change in the external magnetic field is not linear, when the external magnetic field H is not 0, the magnetic core 4a generated when an alternating current is passed through both ends of the exciting coil 7, Since the amount by which the magnetic flux in 4b is increased by the external magnetic field H is not equal to the amount by which the magnetic flux is decreased, an induced electromotive force corresponding to the magnitude of the external magnetic field H is generated in the detection coil 6. Therefore, the external magnetic field H that penetrates the magnetic sensor 10 can be detected by measuring the voltage between the output terminals 2a and 2b.

  According to the magnetic sensor 10 of this example having such a configuration, the structure of the magnetic cores 4a and 4b can be greatly simplified, so that the magnetic sensor 10 having a simple structure and easy to manufacture can be obtained.

  Further, according to the magnetic sensor 10 of this example, the excitation coil 7 does not need to be wound around the magnetic cores 4a and 4b, and may be a flat coil. Therefore, the excitation coil 7 is formed with a conductor pattern formed on the insulating plate 5. Since the magnetic sensor 10 can be configured, the magnetic sensor 10 having a simpler structure and easier to manufacture can be obtained.

  In the magnetic sensor 10 of this example, the magnetic cores 4a and 4b can be formed using a ferromagnetic material such as iron, nickel, cobalt, and the like. Further, as described in Patent Document 1, a structure in which a magnetic fluid is enclosed may be used. In this case, the space in which the magnetic fluid is sealed functions as the magnetic cores 4a and 4b. The shape of the magnetic cores 4a and 4b may be any shape as long as it has an opposing surface that sandwiches the exciting coil 7 and the insulating plate 5, and may be rectangular or semi-cylindrical.

  The insulating plate 5 is preferably formed using a material that is not magnetized, so that the magnetic cores 4a and 4b can be stably opposed to each other at a minute interval. Further, when the exciting coil 7 is formed with a conductor pattern, it is desirable that the exciting coil 7 be an insulator or a dielectric. Therefore, for example, it can be formed using a synthetic resin, a dielectric ceramic, or the like.

(Second example of embodiment)
FIG. 3 is an external perspective view schematically showing a current sensor according to a second example of the embodiment of the present invention. In this example, parts different from the example of the embodiment described above will be described, and the same constituent elements will be denoted by the same reference numerals and redundant description will be omitted.

  As shown in FIG. 3, the current sensor of this example includes the first magnetic sensor 10 of the first example of the embodiment shown in FIGS. 1 and 2, and the first and second coils arranged. And a conductive path 8 through which a current i having a component in a direction (-z direction in the figure) perpendicular to the direction (x-axis direction in the figure) flows.

  According to the current sensor of this example having such a configuration, a magnetic field having a component in the x-axis direction of the figure in the detection coil 6 of the magnetic sensor 10 corresponding to the magnitude of the current i flowing through the conductive path 8. Will occur. Therefore, the distance between the magnetic sensor 10 and the conductive path 8 is measured in advance, and an AC voltage is applied to the input terminals 3a and 3b of the magnetic sensor 10 to measure the voltage between the output terminals 2a and 2b. A current sensor capable of measuring the magnitude of the current i flowing through the path 8 can be obtained.

  According to the current sensor of this example, since the magnetic sensor 10 having a simple structure is used, a direct current can be measured in the same manner as the current sensor described in Patent Document 1, and the structure is simple and manufactured. An easy current sensor can be obtained.

  In the current sensor of this example, the example in which the conductive path 8 is arranged so that the current flows in the z-axis direction in the figure is shown, but the direction in which the first and second coils are arranged (x in the figure). If the conductive path 8 is arranged so that the current flows in a direction perpendicular to the axial direction (an arbitrary direction in the yz plane in the figure), the current can be detected with the same sensitivity. Further, although the detection sensitivity is lowered, in principle, the current can be detected if the current has a component in an arbitrary direction in the yz plane of the drawing.

(Third example of embodiment)
FIG. 4 is an external perspective view schematically showing a magnetic sensor of a third example of an embodiment of the present invention and a current sensor using the same. FIG. 5 is an exploded perspective view schematically showing the magnetic sensor and the current sensor shown in FIG. In FIG. 5, the detection coil 6 is not shown for easy viewing. Moreover, in this example, a different part from the example of embodiment mentioned above is demonstrated, the same code | symbol is attached | subjected to the same component and the overlapping description is abbreviate | omitted.

  The current sensor of this example includes a magnetic sensor 10 and a conductive path 8 as shown in FIGS.

  In the magnetic sensor 10 of the present example, a pair of magnetic cores 4a and 4b are formed in an annular shape, and the first coil 7a and the first coil 7a are arranged along the circumferential direction of the ring of the pair of magnetic cores 4a and 4b. A plurality of second coils 7b are alternately arranged. The conductive path 8 is disposed so as to penetrate the center of the ring of the pair of magnetic cores 4a and 4b vertically (z-axis direction in the drawing).

  According to the magnetic sensor 10 of this example, since the magnetic cores 4a and 4b are formed in an annular shape, the magnetic cores 4a and 4b pass through the inside of the ring at any position inside the ring of the magnetic cores 4a and 4b. By disposing the conductive path 8, it can function as a current sensor that detects the current flowing through the conductive path 8, so that a magnetic sensor that can function as a current sensor with a high degree of freedom during installation can be obtained. it can.

According to the current sensor of this example, the conductive path 8 is located at an arbitrary position inside the ring of the magnetic cores 4a and 4b.
Therefore, a current sensor having a high degree of freedom in the positional relationship between the magnetic cores 4a and 4b and the conductive path 8 can be obtained.

  The conductive path 8 has the highest current detection sensitivity when passing vertically through the ring of the pair of magnetic cores 4a and 4b (in the z-axis direction in the figure), but the current flowing through the conductive path 8 is If it has a component in the direction (z-axis direction in the figure) perpendicular to the plane (xy plane in the figure) on which the rings of the magnetic cores 4a and 4b are located, the current can be detected.

(Fourth example of embodiment)
FIG. 6 is an exploded perspective view schematically showing a current sensor according to a fourth example of the embodiment of the present invention. FIG. 7 is a top view schematically showing the current sensor shown in FIG. In FIG. 6, the detailed illustration of the exciting coil 7 is omitted for the sake of clarity, and only a part of the second through conductor 61 constituting the detection coil 6 is shown. Moreover, in FIG. 7, the description of the exciting coil 7 is omitted. Note that in this example, a different part from the current sensor of the third example of the above-described embodiment will be described, and the same constituent elements will be denoted by the same reference numerals and redundant description will be omitted.

  As shown in FIGS. 6 and 7, the current sensor of this example is formed in a dielectric substrate 21 formed by laminating a plurality of dielectric layers 21 a to 21 e.

  The magnetic cores 4 a and 4 b are arranged in the dielectric substrate 21 with a gap in the thickness direction of the dielectric substrate 21. That is, the magnetic core 4a is disposed on the dielectric layer 21b, and the magnetic core 4b is disposed on the dielectric layer 21d.

  The exciting coil 7 is disposed at a position between the pair of magnetic cores 4 a and 4 b in the dielectric substrate 21. Specifically, it is formed by a conductor pattern disposed on the dielectric layer 21c located between the dielectric layer 21b and the dielectric layer 21d. Although the detailed illustration of the exciting coil 7 is omitted, both ends of the exciting coil 7 are connected to input terminals 3a and 3b arranged on the dielectric layer 21c. Current is supplied.

  The detection coil 6 includes a plurality of second through conductors 61a to 61m penetrating a part of the dielectric substrate 21 in the thickness direction, and a plurality of second conductor patterns arranged inside or on the surface of the dielectric substrate 21. 62a to 62n are connected to each other. Specifically, the second through conductors 61a to 61m and the second conductor patterns 62a to 62n are formed by 62a, 61a, 62b, 61b, 62c, 61c, 62d, 61d, 62e, 61e, 62f, 61f, 62g, 61g. , 62h, 61h, 62i, 61i, 62j, 61j, 62k, 61k, 62l, 61l, 62m, 61m, and 62n in this order. Further, both ends of the detection coil 6 are connected to output terminals 2a and 2b arranged on the upper surface of the dielectric substrate 21, and a current flowing through the conductive path 8 is caused by signals output from the output terminals 2a and 2b. To detect. In FIG. 6, only four second through conductors 61a, 61b, 61g, and 61h among the plurality of second through conductors 61a to 61m are illustrated, and the remaining second through conductors 61c are illustrated. , 61d, 61e, 61f, 61i, 61j, 61k, 61l and 61m are not shown.

  The conductive path 8 includes a first through conductor 81 penetrating a part of the dielectric substrate 21 in the thickness direction, and a plurality of first conductor patterns 82a and 82b arranged in or on the surface of the dielectric substrate 21. Connected and configured. Specifically, the first through conductor 81 and the first conductor patterns 82a and 82b are connected in the order of 82a, 81, and 82b. Further, both ends of the conductive path 8 are connected to a terminal 9a disposed on the upper surface of the dielectric substrate 21 and a terminal 9b disposed on the dielectric layer 21e, and the terminals 9a and 9b are connected from an external circuit (not shown). A current to be measured is passed through.

According to the current sensor of this example having such a configuration, since the current sensor can be formed in the dielectric substrate 21, a current sensor that is small and easy to manufacture can be obtained. In addition, since the mutual positional relationship among the magnetic cores 4a and 4b, the excitation coil 7, the detection coil 6 and the conductive path 8 can be fixed, a highly accurate current sensor can be obtained.

  In the current sensor of this example, the magnetic cores 4a and 4b are composed of a ferromagnetic pattern disposed on the dielectric layer 21c. For example, iron, nickel, cobalt, ferrite, or the like can be used as the ferromagnetic material. Alternatively, the magnetic cores 4a and 4b may be formed by forming a region made of a ferromagnetic material in the dielectric layer 21c.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and improvements can be made without departing from the scope of the present invention.

  For example, in the example of the embodiment described above, the first coil 7a and the second coil 7b adjacent to each other are wound in opposite directions and electrically connected in series. However, the present invention is not limited to this. For example, they may be wound in the same direction and electrically connected in parallel so that current flows in the opposite direction.

  Moreover, in the 1st and 2nd example of embodiment mentioned above, the example which has the 1st coil 7a and the 2nd coil 7b one by one is shown, and in the 3rd example, the 1st coil 7a However, the present invention is not limited to this, and a large number of first coils 7a and second coils 7b may be formed. However, in order to reduce the leakage magnetic field, it is desirable that the magnetic field generated by the first coil 7a and the magnetic field generated by the second coil 7b are equal, so the first coil 7a and the second coil 7b are The same shape and number are desirable.

  Furthermore, in the example of the embodiment described above, the example in which the exciting coil 7 is configured by the conductor pattern formed on the surface of the insulating plate 5 is shown, but the present invention is not limited to this. For example, you may make it comprise with the conductor pattern formed in the inside of the insulating board 5. FIG. Moreover, the exciting coil 7 may be an air-core coil disposed between the magnetic cores 4a and 4b.

  Furthermore, in the second example of the embodiment described above, an example in which the magnetic cores 4a and 4b are rectangular parallelepiped shapes is shown, and in the third example of the embodiment, the magnetic cores 4a and 4b are true. Although an example of a circular ring is shown, the present invention is not limited to this. For example, hexagonal or octagonal polygonal magnetic cores 4a and 4b may be used.

4a, 4b: Magnetic core 6: Coil for detection 7: Excitation coil 8: Conducting path
10: Magnetic sensor
21: Dielectric substrate
61a to 61m: second through conductor
62a to 62n: second conductor pattern
81: First through conductor
82a, 82b: first conductor pattern

Claims (5)

A pair of magnetic cores having the same shape and facing each other;
An exciting coil composed of first and second coils sandwiched between the pair of opposing surfaces of the pair of magnetic cores and disposed adjacent to each other;
A detection coil arranged to surround at least a part of the pair of magnetic cores,
The excitation coil generates a magnetic field having components opposite to each other perpendicular to the facing surface in the first and second coils when a current is passed therethrough,
The detection coil is wound so as to generate a magnetic field having a component in the same direction as the direction in which the first and second coils are arranged in the detection coil when a current is passed. Magnetic sensor characterized by the above.   The pair of magnetic cores are formed in an annular shape, and a plurality of the first and second coils are alternately arranged along the circumferential direction of the ring of the pair of magnetic cores. The magnetic sensor according to claim 1.   A current sensor comprising: the magnetic sensor according to claim 1; and a conductive path for flowing a current having a component in a direction perpendicular to a direction in which the first and second coils are arranged.   3. A current sensor comprising: the magnetic sensor according to claim 2; and a conductive path disposed so as to pass through the inside of the ring of the pair of magnetic cores. The pair of magnetic cores are disposed in the dielectric substrate at intervals in the thickness direction of the dielectric substrate,
The exciting coil is disposed at a position between the pair of magnetic cores in the dielectric substrate;
The conductive path is connected to a first through conductor that penetrates at least a part of the dielectric substrate in a thickness direction, and a plurality of first conductor patterns arranged inside or on the surface of the dielectric substrate. Configured,
The detection coil includes a plurality of second through conductors penetrating at least a part of the dielectric substrate in a thickness direction, and a plurality of second conductor patterns arranged inside or on the surface of the dielectric substrate. The current sensor according to claim 4, wherein the current sensor is connected.

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