JP2013113718A - Magnetic sensor and current sensor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic sensor capable of achieving a current sensor which can be set so as to able to detect current without cutting off a conductive path and has high accuracy, and a current sensor using the magnetic sensor.SOLUTION: The magnetic sensor has at least an annular magnetic path 51 formed separably in at least one cross section perpendicular to a circular direction and a coil 32 wound so as to surround at least a portion of the annular magnetic path 51, wherein the cross section area of a cross section where the annular magnetic path 51 is separable is larger than the cross section area of another cross section perpendicular to a circular direction of the annular magnetic path 51. The current sensor uses the magnetic sensor. It is possible to acquire the magnetic sensor which can achieve a current sensor that can be set in a state where the current sensor can detect current without cutting off a conductive path and has high accuracy, and a current sensor using the magnetic sensor.

Description

  The present invention relates to a magnetic sensor and a current sensor using the magnetic sensor.

  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). In addition, a current sensor having a separable annular magnetic path has been proposed in order to accommodate the conductive path through which the current to be measured flows inside the annular magnetic path without cutting (see, for example, Patent Document 2). ).

Japanese Patent No. 4310373 JP 2006-84176 A

  However, although the current sensor proposed in Patent Document 1 can measure current with high accuracy, there is a problem in that it cannot be accommodated inside the annular magnetic path without cutting the conductive path through which the current to be measured flows. It was. Further, when the annular magnetic path can be divided as in the current sensor proposed in Patent Document 2, the magnetic resistance of the annular magnetic path changes when a deviation occurs in the divided portion. There was a problem that the measurement accuracy was lowered.

  The present invention has been devised in view of such problems in the prior art, and an object of the present invention is to set the current in a detectable state without cutting the conductive path and to achieve accuracy. An object of the present invention is to provide a magnetic sensor capable of realizing a high current sensor and a current sensor using the same.

  The magnetic sensor of the present invention includes a first annular magnetic path formed so as to be separable in at least one cross section perpendicular to the circumferential direction, and a first annular magnetic path wound around at least a part of the first annular magnetic path. The cross-sectional area of the first annular magnetic path is separable from the cross-sectional area of another cross-section perpendicular to the circumferential direction of the first annular magnetic path. It is characterized by being large.

  The current sensor of the present invention includes the magnetic sensor, and a conductive path for passing a current to be measured is disposed so as to pass through the inside of the first annular magnetic path. .

  According to the magnetic sensor of the present invention, it is possible to obtain a magnetic sensor that can be set in a state where current can be detected without cutting the conductive path and can realize a highly accurate current sensor.

  According to the current sensor of the present invention, it is possible to set the current sensor in a state where the current can be detected without cutting the conductive path and to obtain a current sensor with high accuracy.

It is a perspective view which shows typically the current sensor of the example of embodiment of this invention. It is a perspective view which shows typically the current sensor of the example of embodiment of this invention.

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

  1 and 2 are perspective views schematically showing a current sensor according to an embodiment of the present invention. As shown in FIGS. 1 and 2, the current sensor of this example includes arc-shaped magnetic paths 11 to 14, connection magnetic paths 21 and 22, and coils 31 and 32. In FIG. 1, the arc-shaped magnetic paths 11 and 13 are arranged on the same circumference and joined together to form an annular magnetic path 51, and the arc-shaped magnetic paths 12 and 14 are arranged on the same circumference. In addition, the annular magnetic path 52 is formed by being joined to each other. And the conductive path 41 for flowing the electric current of a measuring object is arrange | positioned so that the inner side of the annular magnetic paths 51 and 52 may be passed. The current sensor of this example is a magnetic sensor that detects the magnetic field in the circumferential direction (θ direction, −θ direction in FIG. 1) of the annular magnetic path 51 and the annular magnetic path 52 when the conductive path 41 is not disposed. Function. 2 shows a state in which the annular magnetic path 51 is separated into the arc-shaped magnetic path 11 and the arc-shaped magnetic path 13, and the annular magnetic path 52 is separated into the arc-shaped magnetic path 12 and the arc-shaped magnetic path 14. The conductive path 41 is not shown.

  The annular magnetic path 51 has a substantially annular shape and is formed so as to be separable into the arc-shaped magnetic paths 11 and 13 in the cross sections 61 and 62 perpendicular to the circumferential direction (the θ direction and the −θ direction in FIG. 1). Has been. In the annular magnetic path 51, the cross-sectional areas of the separable cross sections 61 and 62 are larger than the cross-sectional areas of other cross sections perpendicular to the circumferential direction of the annular magnetic path 51 (the θ direction and the −θ direction in FIG. 1). It is supposed to be. That is, in the annular magnetic path 51, the cross-sectional area of the cross sections 61 and 62 perpendicular to the circumferential direction (the θ direction and the −θ direction in FIG. 1) in the separable portion has a circumferential direction ( The cross-sectional area of the cross section perpendicular to the θ direction and the −θ direction in FIG. 1 is made larger. That is, the annular magnetic path 51 has a shape in which the separable part is swollen more than the other part.

  The annular magnetic path 52 has the same shape and structure as the annular magnetic path 51, and generally faces the annular magnetic path 51 and is perpendicular to the circumferential direction (the θ direction and the −θ direction in FIG. 1). The separable cross sections 63 and 64 are separable into arc-shaped magnetic paths 12 and 14. The separable cross sections 63 and 64 of the annular magnetic path 52 are arranged at the same positions as the separable cross sections 61 and 62 of the annular magnetic path 51. In the annular magnetic path 52, the cross-sectional areas of the separable cross sections 63 and 64 are larger than the cross-sectional areas of other cross sections perpendicular to the circumferential direction of the annular magnetic path 52 (the θ direction and the −θ direction in FIG. 1). It is supposed to be. That is, in the annular magnetic path 52, the cross-sectional area of the cross sections 63 and 64 perpendicular to the circumferential direction (θ direction, −θ direction in FIG. The cross-sectional area of the cross section perpendicular to the θ direction and the −θ direction in FIG. 1 is made larger. That is, the annular magnetic path 52 has a shape in which the separable part is swollen more than the other part.

  The arc-shaped magnetic paths 11 to 14 have the same shape, and each has a substantially semicircular arc shape. The arc-shaped magnetic paths 11 and 12 are arranged so as to face each other with a predetermined interval. The first portions 71, which are central portions of the arc-shaped magnetic paths 11 and 12 and are opposed to each other, are connected by the connection magnetic path 21. The arc-shaped magnetic paths 13 and 14 are arranged so as to face each other with a predetermined interval. The second portions 72, which are central portions of the arc-shaped magnetic paths 13 and 14 and are opposed to each other, are connected by the connection magnetic path 22.

The arc-shaped magnetic paths 11 and 13 are arranged on the same circumference and joined together to form an annular magnetic path 51. More specifically, one end face 61 a of the arc-shaped magnetic path 11 and one end face 61 b of the arc-shaped magnetic path 13 are joined, and the other end face 62 a of the arc-shaped magnetic path 11 and the arc-shaped magnetic path 13 are connected. The other end face 62b is joined to form the annular magnetic path 51. Therefore, the joint surface between the end surface 61 a of the arc-shaped magnetic path 11 and the end surface 61 b of the arc-shaped magnetic path 13 becomes a separable cross section 61 in the annular magnetic path 51, and the end surface 62 a of the arc-shaped magnetic path 11 and the arc-shaped magnetic path 13 is a separable cross-section 62 in the annular magnetic path 51.

  Similarly, the arc-shaped magnetic paths 12 and 14 are arranged on the same circumference and joined together to form the annular magnetic path 52. More specifically, one end face 63 a of the arc-shaped magnetic path 12 and one end face 63 b of the arc-shaped magnetic path 14 are joined, and the other end face 64 a of the arc-shaped magnetic path 12 and the arc-shaped magnetic path 14 are joined. The other end face 64b is joined to form the annular magnetic path 52. Therefore, the joint surface between the end face 63a of the arc-shaped magnetic path 12 and the end face 63b of the arc-shaped magnetic path 14 becomes a separable cross section 63 in the annular magnetic path 52, and the end face 64a of the arc-shaped magnetic path 12 and the arc-shaped magnetic path 14 is a separable cross-section 64 in the annular magnetic path 52.

  In the annular magnetic paths 51 and 52, the first portion 71 is a portion not including the separable cross sections 61 to 64, and the second portion 72 is a portion not including the separable cross sections 61 to 64. This is a part different from the first part 71.

  The coil 31 is wound so as to surround the connection magnetic path 21. The coil 32 is wound so as to collectively surround the annular magnetic paths 51 and 52 (the arc-shaped magnetic paths 13 and 14). 1 and 2 show an example in which the coil 32 is wound around a part of the arc-shaped magnetic paths 13 and 14 that are a part of the annular magnetic paths 51 and 52, but in order to increase the sensitivity of the sensor. It is desirable that the coil 32 is wound around the entire annular magnetic paths 51 and 52. That is, it is desirable that the coil 32 is wound around the entire arc-shaped magnetic paths 11 and 12 and the entire arc-shaped magnetic paths 13 and 14. Similarly, the coil 31 is preferably wound around the entire connection magnetic path 21. Further, terminals 31 a and 31 b are provided at both ends of the coil 31, and terminals 32 a and 32 b are provided at both ends of the coil 32.

  In the current sensor of this example, an alternating current is passed through the coil 31. For example, when a current flows in a direction from the terminal 31a to the terminal 31b at a certain moment, a magnetic field in the z direction in FIG. 1 is generated in the coil 31, and thereby, in the connection magnetic path 21 in FIG. A magnetic flux is generated in the z direction. This magnetic flux is separated into the θ direction and the −θ direction in FIG. 1 in the first portion 71 of the annular magnetic path 51 and merged in the second portion 72 of the annular magnetic path 51, and then the connection magnetic path 22 in FIG. -Z direction. Then, after the second portion 72 of the annular magnetic path 52 is separated again in the θ direction and the −θ direction of FIG. 1 and merged again in the first portion 71 of the annular magnetic path 52, the connection magnetic path 21 is illustrated in FIG. Heading in the z direction of 1. Thus, the magnetic flux flows through the magnetic path constituted by the annular magnetic paths 51 and 52 and the connecting magnetic paths 21 and 22.

  At this time, when no current is flowing through the conductive path 41, a magnetic flux is present in the annular magnetic path 51 in the θ direction in FIG. 1 and the annular magnetic path 52 is in the coil 32. There is a magnetic flux toward the -θ direction in FIG. Since the two magnetic fluxes in the opposite directions are equal, the magnetic fluxes that cancel each other and penetrate the coil 32 are zero. When the direction of the current flowing through the coil 31 is reversed, the direction of the magnetic flux in each magnetic path is also reversed, but similarly, the magnetic flux passing through the coil 32 is zero. Therefore, even if an alternating current is passed through the coil 31, no induced electromotive force is generated between the terminals 32a and 32b at both ends of the coil 32.

When the current i flowing in the z direction in FIG. 1 flows through the conductive path 41, a magnetic field in the θ direction in FIG. 1 is generated around the conductive path 41, and thereby, in both the annular magnetic paths 51 and 52, as shown in FIG. Magnetic flux in the θ direction is generated. On the other hand, as described above, the magnetic flux generated by the alternating current flowing through the coil 31 is reversed between the annular magnetic path 51 and the annular magnetic path 52. For this reason, on one of the annular magnetic paths 51 and 52, the direction of the magnetic flux due to the alternating current flowing through the coil 31 and the direction of the magnetic flux due to the current flowing through the conductive path 41 coincide with each other to increase the magnetic flux. On the other hand, the direction of the magnetic flux due to the alternating current flowing through the coil 31 and the direction of the magnetic flux due to the current flowing through the conductive path 41 are reversed, and the magnetic flux decreases.

  However, since the change in magnetic permeability of the magnetic material due to the change in the external magnetic field is not linear, the magnetic flux generated by the current i flowing in the conductive path 41 is caused by the magnetic flux in the annular magnetic paths 51 and 52 generated by the alternating current flowing in the coil 31. The amount of increase and decrease is not equal to each other. As a result, an induced electromotive force corresponding to the magnitude of the current i flowing through the conductive path 41 is generated in the coil 32. Therefore, the magnitude of the current i flowing through the conductive path 41 can be obtained by measuring the voltage between the terminals 32 a and 32 b provided at both ends of the coil 32. In this way, the current sensor of this example functions as a current sensor.

  In addition, the current sensor of this example can separate the arc-shaped magnetic path 11 and the arc-shaped magnetic path 13 and can separate the arc-shaped magnetic path 12 and the arc-shaped magnetic path 14. Therefore, the current sensor of this example can be set to a state in which the measured current flowing through the conductive path 41 can be detected without cutting the conductive path 41.

  Further, in the current sensor of this example, the cross-sectional areas of the separable cross sections 61 to 64 in the annular magnetic paths 51 and 52 are in the circumferential direction (the θ direction in FIG. 1, − It is larger than the cross-sectional area of the cross section perpendicular to the (θ direction). As a result, even when a misalignment occurs in the separable cross sections 61 to 64, the cross sectional area at the joint surface (cross sections 61 to 64) is smaller than the cross sectional areas at the other portions of the annular magnetic paths 51 and 52. Can be made difficult to occur. Thereby, since the increase in the magnetic resistance of the annular magnetic paths 51 and 52 due to the displacement of the joint surfaces (cross sections 61 to 64) can be reduced, a highly accurate current sensor can be obtained. Therefore, according to the current sensor of this example, it is possible to set the current sensor in a state where the current can be detected without cutting the conductive path and to obtain a highly accurate current sensor.

  In the current sensor of this example, the arc-shaped magnetic paths 11 to 14 and the connection magnetic paths 21 and 22 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 portions where the magnetic fluid exists function as arc-shaped magnetic paths 11 to 14 and connection magnetic paths 21 and 22. Furthermore, the arc-shaped magnetic paths 11 to 14 and the connection magnetic paths 21 and 22 may be configured using a solid superparamagnetic material.

(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, an example in which the coil 31 is wound around the connection magnetic path 21 is shown, but the present invention is not limited to this. For example, the coil 31 may be wound around both the connection magnetic paths 21 and 22. In this case, it is necessary to reverse the direction of the magnetic flux generated in the connection magnetic path 21 and the direction of the magnetic flux generated in the connection magnetic path 22.

  Moreover, in the example of embodiment mentioned above, although each of the annular magnetic paths 51 and 52 showed the example which has two separable cross sections, it is not limited to this. Each of the annular magnetic paths 51 and 52 may have only one separable cross section, and each of the annular magnetic paths 51 and 52 may have three or more separable cross sections.

  Furthermore, in the example of the embodiment described above, an example in which the conductive path 41 for flowing the current to be measured is disposed so as to pass through the annular magnetic paths 51 and 52 and used as a current sensor. Although shown, it is not limited to this. You may use as a magnetic sensor which detects the magnetic field of the circumference direction (theta direction of FIG. 1,-(theta) direction) of the annular magnetic paths 51 and 52. FIG.

  Furthermore, in the example of embodiment mentioned above, although the example which has the annular magnetic paths 51 and 52, the connection magnetic paths 21 and 22, and the coils 31 and 32 was shown, it is not limited to this. . For example, it may be a magnetic sensor or a current sensor constituted only by the annular magnetic path 51 and the coil 32 wound so as to surround it. In that case, a conductive path 41 for passing a current to be measured may be disposed so as to pass inside the annular magnetic path 51.

21, 22: Connection magnetic path 31, 32: Coil 41: Conduction path 51, 52: Annular magnetic path 61, 62, 63, 64: Separable cross section 71: First part 72: Second part

Claims (4)

A first annular magnetic path formed so as to be separable in at least one cross section perpendicular to the circumferential direction;
And at least a first coil wound around at least a part of the first annular magnetic path,
A magnetic sensor characterized in that a cross-sectional area of the separable cross section of the first annular magnetic path is larger than a cross-sectional area of another cross section perpendicular to the circumferential direction of the first annular magnetic path. The first annular magnetic path has the same shape and structure, and is generally opposed to the first annular magnetic path and has a separable cross-section capable of separating the first annular magnetic path. A second annular magnetic path arranged to be at the same position as the cross section;
In the first and second annular magnetic paths, a first connecting magnetic path that connects the first parts that are parts that are opposed to each other and that do not include the separable cross section;
A second part of the first and second annular magnetic paths that are opposed to each other and that does not include the separable cross section and connects second parts that are different from the first part. Connecting magnetic path,
A second coil wound so as to surround at least a part of the first connection magnetic path,
The magnetic sensor according to claim 1, wherein the first coil is wound so as to collectively surround at least a part of the first and second annular magnetic paths.   A current sensor comprising the magnetic sensor according to claim 1, wherein a conductive path for passing a current to be measured is disposed so as to pass through the inside of the first annular magnetic path.   A current sensor comprising the magnetic sensor according to claim 2, wherein a conductive path for passing a current to be measured is disposed so as to pass through the inside of the first and second annular magnetic paths. .

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