JPWO2018116852A1 - Current sensor - Google Patents

Abstract

The four first magnetoelectric transducers 15a, 15b, 15c, 15d are disposed on the virtual rectangle L1 around the center PP of the measured current path CB, and the six second magnetoelectric transducers 17a are disposed on the inner side thereof. , 17b, 17c, 17d, 17e, 17f are disposed. The second magnetoelectric transducers 17a to 17c are located on the imaginary straight line L3, and the second magnetoelectric transducers 17d to 17f are located on the straight line L4. The imaginary straight lines L3 and L4 are line symmetrical with respect to the center line L2.

Description

  The present invention relates to a current sensor for detecting a current flowing in a current path to be measured, and more particularly to a current sensor for detecting a current flowing in a current path to be measured using a magnetoelectric conversion element.

BACKGROUND There are well-known current sensors attached to a measured current path and detecting a current flowing in the measured current path for control and monitoring of various electronic devices. As this type of current sensor, a current sensor using a magnetoelectric conversion element such as a Hall element or a magnetoresistance element is known. A plurality of magnetoelectric elements are used to improve the sensitivity of the magnetoelectric conversion element or to reduce the influence from an external magnetic field. Conversion elements may be used.
As described above, in the current sensor using a plurality of magnetoelectric conversion elements, the plurality of magnetoelectric conversion elements are disposed on a virtual circle around the current path to be measured in accordance with the direction of the magnetic field generated around the current path to be measured. Was.

  However, as described above, when the magnetoelectric conversion element is disposed on the virtual circle, there is a problem that the current sensor can not be installed when the current sensor is enlarged and the distance between the current path to be measured and the neighboring current path is short.

In order to solve such a problem, in the current sensor of Patent Document 1, on a virtual ellipse centering on the position of the current path to be measured and having a short axis a direction connecting the current path to the current and the neighboring current path. A plurality of magnetoelectric conversion elements are provided. Further, in the current sensor of Patent Document 2, a plurality of magnetoelectric conversion elements are disposed on a virtual rectangle or a virtual ellipse and a virtual rectangle.
According to the current sensor, stable current detection can be performed without being greatly affected by the external magnetic field in the neighboring current path, and downsizing can be achieved.

International Publication WO2013 / 128993 International Publication WO2015 / 122064

By the way, in recent years, the space between the adjacent electric wires has become narrower due to the miniaturization of the electronic board and the inverter.
From such a background, the current sensor can be installed even when the distance between the current path to be measured and the neighboring current path is further short, and stable current detection without being greatly affected by the external magnetic field of the neighboring current path. I have a request to do it.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a current sensor capable of performing stable current detection without being greatly affected by an external magnetic field in a nearby current path while achieving further downsizing. It is in.

  In order to solve the problems of the prior art described above and to achieve the above-described object, the current sensor of the present invention is provided on a wiring board and the wiring board, and generates magnetism generated by current flowing in a current path to be measured. A plurality of magnetoelectric conversion elements to be detected are provided, and a notch for positioning the measured current path is formed at the center of a virtual rectangle in the wiring substrate, and the plurality of magnetoelectric conversion elements are four of the virtual rectangles. The first magnetoelectric conversion element comprising four first magnetoelectric conversion elements located at two vertexes, and at least four second magnetoelectric conversion elements located at point-symmetrical positions with respect to the center of the virtual rectangle; The direction of the sensitivity axis of the element is orthogonal to the attaching / detaching direction of the current path to be measured along the notch, and the direction of the sensitivity axis of the second magnetoelectric conversion element is parallel to the attaching / detaching direction, Point symmetry to the center of the virtual rectangle The first electromagnetic element and between the orientation of the sensitivity axis between the second magnetoelectric transducer in location are parallel, the second of the electromagnetic element is positioned inside the imaginary rectangle.

  According to this configuration, the second magnetoelectric conversion element and the second magnetoelectric conversion element are arranged in a straight line by arranging the second magnetoelectric conversion element inside the virtual rectangle in which the first magnetoelectric conversion element is located at the vertex. Compared to the case where the element is arranged, the magnetic field of the neighboring current path generated in the first magnetoelectric conversion element farther from the neighboring current path than the second magnetoelectric conversion element can be strengthened. This makes it possible to make the absolute values of the sum of the + component and the sum of the component according to the magnetic fields of the neighboring current paths coincide with each other, and cancel them with high accuracy.

  Preferably, the plurality of second magnetoelectric conversion elements on one side and the plurality of second magnetoelectric conversion elements on the other side with respect to a center line passing the center and parallel to the mounting and demounting direction Each is disposed on a virtual straight line parallel to the center line.

  According to this configuration, it is sufficient to adjust the position of the second magnetoelectric conversion element on the imaginary straight line, which facilitates design for enhancing the measurement accuracy.

  Preferably, the plurality of second magnetoelectric conversion elements on one side and the plurality of second magnetoelectric conversion elements on the other side are disposed in line symmetry with respect to the center line.

  According to this configuration, since the second magnetoelectric conversion elements are disposed in line symmetry with respect to the center line, the symmetry is maintained, and a uniform extraneous magnetic field such as geomagnetism can be canceled with high accuracy.

  Preferably, the long side of the virtual rectangle is parallel to the center line, and the short side is orthogonal to the center line.

  According to this configuration, since the short side of the virtual rectangle in which the first magnetoelectric conversion element is disposed at the apex is orthogonal to the central axis, the necessity in the direction orthogonal to the central axis on which the magnetoelectric conversion element is disposed Distance can be shortened. That is, the distance between the current path to be measured and the neighboring current path can be narrowed.

  Preferably, the plurality of second magnetoelectric transducers are disposed on a virtual ellipse centered on the center of the virtual rectangle.

  According to this configuration, it is sufficient to adjust the position of the second magnetoelectric conversion element on the virtual ellipse centered on the center of the virtual rectangle, and the design for enhancing the measurement accuracy becomes easy. Also, the distance between the current path to be measured and the neighboring current path can be narrowed.

  Preferably, the first magnetoelectric conversion element is arranged such that the sensitivity axes of the first magnetoelectric conversion element and the second magnetoelectric conversion element turn in one direction along a closed path surrounding the center of the virtual rectangle. And the second magnetoelectric conversion element is disposed.

  According to this configuration, the directions of the sensitivity axis of the magnetoelectric conversion element and the magnetic field of the current path to be measured can be aligned, the magnetic field of the current path to be measured can be efficiently detected, and the measurement accuracy can be enhanced.

  Preferably, the first magnetoelectric conversion element and the second magnetoelectric conversion element have the same characteristics.

  According to the present invention, it is possible to provide a current sensor capable of performing stable current detection without being greatly affected by the external magnetic field of the adjacent current path while achieving further downsizing.

It is an exploded perspective view showing the current sensor concerning the embodiment of the present invention. It is a perspective view showing the current sensor concerning the embodiment of the present invention. It is a figure for demonstrating arrangement | positioning of the magnetoelectric conversion element of the current sensor which concerns on embodiment of this invention, Comprising: It is a top view of the wiring board seen from Z1 side shown in FIG. It is a figure for demonstrating the neighboring current path of the current sensor shown in FIG. FIG. 5 is a diagram for illustrating the influence of a magnetic field from a neighboring current path CN1 shown in FIG. 4 in the current sensor shown in FIG. 3. It is a figure for demonstrating the 1st modification of arrangement | positioning of the magnetoelectric conversion element of the current sensor which concerns on embodiment of this invention, Comprising: It is a top view of the wiring board seen from Z1 side shown in FIG. It is a figure for demonstrating the 2nd modification of arrangement | positioning of the magnetoelectric conversion element of the current sensor which concerns on embodiment of this invention, Comprising: It is a top view of the wiring board seen from Z1 side shown in FIG.

  FIG. 1 is an exploded perspective view showing a current sensor 101 according to an embodiment of the present invention. FIG. 2 is a perspective view showing a current sensor 101 according to an embodiment of the present invention. FIG. 3 is a view for explaining the current sensor 101 according to the embodiment of the present invention, and is a top view of the wiring board 16 seen from the Z1 side to the Z2 side shown in FIG.

  As shown in FIGS. 1 and 2, the current sensor 101 according to the embodiment of the present invention includes a plurality of magnetoelectric conversion elements 15 for detecting magnetism generated when a current flows in the measured current path CB, and a plurality of magnetoelectric conversion elements. And a wiring substrate 16 on which the magnetoelectric conversion element 15 is disposed. In addition, the current sensor 101 includes a housing 11 having a housing portion 11s for housing the wiring substrate 16, a connector 13 having a takeout terminal 13t for taking out an electric signal from the magnetoelectric conversion element 15, and a measured current path CB. And a holding member 14 for fixing and holding.

  The housing 11 is formed of a synthetic resin material. The housing 11 is composed of a box-like case 31 opened at the upper side and a plate-like cover 41 for closing the opening of the case 31, and a housing portion for housing the wiring board 16 inside the case 31. 11s is formed.

  The case 31 is formed with a recessed portion (concave groove) 32 which is cut out toward the center side of the case 31 from one side thereof, and the current path CB to be measured is introduced and held in the recessed portion 32. It is configured. The back wall 32 a of the recess 32 is formed in a shape complementary to the outer peripheral surface of the current path to be measured CB.

  In the present embodiment, the back wall 32a of the recess 32 is curved in an arc so as to correspond to the outer peripheral surface of the cylindrical current path CB. In addition, notches 32c that lock the free end side of the clip spring 14K are formed at opposing positions on the opposing inner side wall 32b of the case 31 connected to the back wall 32a.

  The notch 32c is cut downward from the upper end portion side of the inner side wall 32b, and the end face on the inlet side is formed to be inclined outward. The measured current path CB is held by the clip spring 14 K which protrudes from the notch 32 c into the recess 32 while the back side of the outer peripheral surface is in contact with the back wall 32 a of the recess 32. It is held relative to the housing 11. The position held by the back wall 32 a of the recess 32 and the clip spring 14 K is the center PP of the measured current path CB with respect to the housing 11. In the present embodiment, the center PP is the center PP of a virtual rectangle L described later.

  In the cover 41, an opening 42 having the same shape is formed on one side so as to correspond to the recess 32 of the case 31, and the connector 13 is provided on the side opposite to the side on which the opening 42 is formed. An opening 43 for exposing the upper end portion of the housing 11 to the outside of the housing 11 is formed.

  The holding member 14 is a member for fixing and holding the current path CB to be measured, and the clip spring 14K sandwiching and holding the outer edge of the current path CB to be measured and the current path CB to be measured are disposed at the center PP. And a pressing member 14H for pressing the clip spring 14K.

  The pressing member 14H is formed in a substantially rectangular parallelepiped shape, and is manufactured in a size to be strongly fitted in the recess 32 formed in the case 31. The pressing member 14H is held in the recess 32 of the case 31 while holding the clip spring 14K.

  The wiring board 16 uses a multilayer printed wiring board (PCB), and a metal foil such as copper (Cu) provided on the wiring board is patterned to form a wiring pattern. The wiring board 16 is formed to have a size that can be stored in the housing portion 11s of the case 31, and a notch 19 in which the current path to be measured CB is inserted and disposed is formed on one side thereof. That is, the wiring board 16 is formed in a similar shape to the bottom surface portion of the housing portion 11s, and a cutout portion 17 having a complementary shape to the concave portion 32 of the case 31 is formed.

  As shown in FIGS. 1 and 3, a plurality of (ten) magnetoelectric conversion elements 15 are arranged in the vicinity of the notch 19 of the wiring substrate 16, and in the vicinity of the side opposite to the side where the cutout 19 is formed. The connector 13 is disposed. The detailed arrangement position of the magnetoelectric conversion element 15 will be described later.

  The connector 13 is provided with a plurality of terminals electrically connected to a mating connector (not shown), and among the plurality of terminals, an extraction terminal 13t is provided to extract an electric signal from the magnetoelectric conversion element 15. ing. Further, the connector 13 is provided with an insulating base 13K for fitting with a mating connector (not shown). The insulating base 13K is formed in a box shape having an open upper side, and a plurality of terminals including the takeout terminal 13t are held and stored in the inside in a state in which the terminals are insulated. In the present embodiment, the connector 13 is used to take out the electric signal from the magnetoelectric conversion element 15. However, the present invention is not limited to the connector 13. For example, even if a flexible printed circuit (FPC) or the like is used. good.

  The magnetoelectric conversion element 15 is a current sensor element that detects magnetism generated when a current flows in the measured current path CB, and for example, a magnetic detection element (GMR (Giant Magneto Resistive)) using a giant magnetoresistance effect. It is possible to use an element). Although this magnetoelectric conversion element 15 is not shown in detail for ease of explanation, after the GMR element is fabricated on a silicon substrate, the cut out chip is packaged with a thermosetting synthetic resin, and the signal is converted. A lead terminal for taking out is electrically connected to the GMR element. Then, the wiring board 16 is soldered by the lead terminals.

As shown in FIG. 3, in the current sensor 101, four first magnetoelectric conversion elements 15a, 15b, 15c, 15d and six second magnetoelectric conversion are provided around the center PP of the measured current path CB. Elements 17a, 17b, 17c, 17d, 17e and 17f are provided.
The first magnetoelectric conversion elements 15a, 15b, 15c, 15d and the six second magnetoelectric conversion elements 17a, 17b, 17c, 17d, 17e, 17f have the same magnetoelectric conversion characteristics. This facilitates design for enhancing the measurement accuracy of the current sensor 101.

As described above, the center PP of the virtual rectangle L1 is the center of the cross section (X, Y cross section) of the measured current path CB. The notch 19 has a shape that allows the center of the current path CB to be measured to be positioned at the center PP of the virtual rectangle L1 when the current sensor 101 is positioned with respect to the current path CB to be measured.
As shown in FIG. 3, on the surface of the wiring board 16 on the left side (X2 direction side) of the notch 19 with respect to the center line L2, the first magnetoelectric conversion elements 15a and 15b and the second magnetoelectric conversion elements 17a and 17b , 17c are provided. Further, on the surface of the wiring board 16 on the right side (X1 direction side) of the notch 19 when viewed from the Y1 direction, the first magnetoelectric conversion elements 15c and 15d and the second magnetoelectric conversion elements 17d, 17e and 17f are disposed. ing.

As shown in FIG. 3, when the virtual rectangle L1 centered on the center PP is defined, the first magnetoelectric transducers 15a to 15d are located at four vertices of the virtual rectangle L1.
Specifically, as shown in FIG. 3, a virtual rectangle is defined when a center line L2 passing through the center PP and parallel to the mounting / removing direction (Y1-Y2 direction) along the notch 32c of the measured current path CB is defined. The long side of L1 is parallel to the center line L2, and the short side thereof is orthogonal to the center line L2.

The second magnetoelectric transducers 17a to 17f are located inside the virtual rectangle L1 and point symmetric with respect to the center PP which is the center of the virtual rectangle L1.
Specifically, as shown in FIG. 3, the second magnetoelectric transducers 17a to 17c are located on the X2 side with respect to the center line L2, and the second magnetoelectric transducers 17d to 17f are located on the X1 side. .
In the example shown in FIG. 3, the second magnetoelectric conversion elements 17a to 17c are located on the imaginary straight line L3 parallel to the Y1-Y2 direction, and the second magnetoelectric conversion elements 17d to 17f are imaginary parallel to the Y1-Y2 direction. It is located on the straight line L4. The imaginary straight lines L3 and L4 are line symmetrical with respect to the center line L2.

  The first magnetoelectric conversion element 15c, the second magnetoelectric conversion elements 17a, 17b and 17c, and the first magnetoelectric conversion element 15b are respectively the first magnetoelectric conversion element 15c, with respect to the center PP of the first rectangle L1. The second magnetoelectric conversion elements 17d, 17e and 17f and the first magnetoelectric conversion element 15d are arranged point-symmetrically.

  When the magnetoelectric conversion elements are arranged at equal intervals on the circumference by arranging the first magnetoelectric conversion elements 15a to 15d and the second magnetoelectric conversion elements 17a to 17f in this manner (comparative example) Compared to the above, the arrangement space of the magnetoelectric conversion element can be reduced while the arrangement of the magnetoelectric conversion element through which the measured current path CB is inserted and disposed.

  That is, in the case of the magnetoelectric conversion element according to the comparative example, the magnetoelectric conversion elements are equally arranged at equal intervals in the circumferential direction centering on the arrangement position of the measured current path CB. Therefore, when the current path CB to be measured is introduced from between the magnetoelectric conversion elements and disposed at the installation position, it is necessary to secure at least a distance through which the current path CB to be measured can pass as the element distance between the magnetoelectric conversion elements Because of the presence, the arrangement area of all the magnetoelectric conversion elements becomes large, and the wiring board becomes larger accordingly.

On the other hand, in the case of the arrangement of the magnetoelectric conversion elements 15 according to the present embodiment, three second magnetoelectric conversion elements 17a, 17b and 17c are disposed on the long side L31 of the second rectangle L3 and three The second magnetoelectric transducers 17f, 17e and 17d are disposed on the long side L32 of the second rectangle L3.
Therefore, the distance in the X1-X2 direction (X direction) necessary for the arrangement of the second magnetoelectric conversion elements 17a, 17b, 17c and the second magnetoelectric conversion elements 17f, 17e, 17d can be shortened. That is, the distance between the current path CB to be measured and the adjacent current paths CN1 and CN2 adjacent to each other can be narrowed.
As a result, in particular, the arrangement region of the magnetoelectric conversion elements in the direction (X1-X2 direction) orthogonal to the formation direction of the notches 19 can be reduced, and the wiring substrate 16 can be miniaturized, that is, the current sensor 101 can be miniaturized. It is. It is important to be able to narrow the width of the left and right arms 18 of the notch 19 particularly in applications where it is desired to provide a plurality of current paths at as narrow intervals as possible, such as a switchboard.

The direction SJ of the sensitivity axis (the direction of sensing magnetism) of the first magnetoelectric transducers 15a to 15d is parallel to the short side of the virtual rectangle L1, that is, the mounting / dismounting direction Y1-Y2 of the measured current path CB to the notch 32c. And orthogonal to This facilitates design for enhancing the measurement accuracy of the current sensor 101.
Specifically, the direction SJ of the sensitivity axis of the first magnetoelectric transducers 15a and 15c is the X1 direction, and the direction SJ of the sensitivity axis of the first magnetoelectric transducers 15d and 15a is the X2 direction.
The direction SJ of the sensitivity axis of the second magnetoelectric conversion elements 17a, 17b and 17c is the Y1 direction, and the direction SJ of the sensitivity axis of the second magnetoelectric conversion elements 17d, 17e and 17f is the Y2 direction.
The first magnetoelectric conversion elements 15a to 15d and the second magnetoelectric conversion elements 17a to 17f have closed sensitivity paths whose directions SJ of sensitivity axes surround the center PP of the virtual rectangle L1 which is the center of the current path CB to be measured. It is disposed so as to turn in one direction (clockwise direction in the present embodiment) along.

As a result, in the second magnetoelectric transducers 17a, 17b, 17 the direction SJ of the sensitivity axis is opposite to that of the second magnetoelectric transducers 17d, 17e, 17f located point-symmetrically with respect to the center PP.
In the arithmetic circuit of the latter stage, the components corresponding to the magnetic field of the measured current path CB are accumulated by adding the outputs of the first magnetoelectric transducers 15a to 15d and the outputs of the second magnetoelectric transducers 17a to 17f. And cancel the component corresponding to the magnetic field of the neighboring current path CN.

FIG. 4 is a diagram for describing a neighboring current path of current sensor 101 shown in FIG.
FIG. 5 is a diagram for explaining the influence of the magnetic field from the neighboring current path CN1 shown in FIG. 4 in the current sensor 101 shown in FIG.
As shown in FIG. 5, the positions of the second magnetoelectric transducers 17d, 17e and 17f are close to the neighboring current path CN1 on the X1 side, and the magnetic field from the magnetic field B1 from the neighboring current path CN1 is strong. Moreover, the direction of the sensitivity axis of the second magnetoelectric transducers 17d, 17e, 17f and the direction of the magnetic field B1 from the neighboring current path CN1 are close to parallel. However, the directions of the sensitivity axes of the second magnetoelectric transducers 17d, 17e and 17f and the direction of the magnetic field B1 from the neighboring current path CN1 are substantially opposite to each other. That is, the component in the sensitivity axis direction of the magnetic field B1 from the adjacent current path CN1 is opposite to the sensitivity axis direction. From the above, in the second magnetoelectric transducers 17d, 17e and 17f, the magnetic field B1 from the neighboring current path CN1 is measured with a large absolute value of negative sign.

  The positions of the second magnetoelectric transducers 17a, 17b and 17c on the X2 side are far from the neighboring current path CN1 on the X1 side, and the magnetic field from the magnetic field B1 from the neighboring current path CN1 is weak. The direction of the sensitivity axis of the second magnetoelectric transducers 17a, 17b and 17c and the direction of the magnetic field B1 from the adjacent current path CN1 are close to parallel. The direction of the sensitivity axis of the second magnetoelectric transducers 17a, 17b and 17c and the direction of the magnetic field B1 from the adjacent current path CN1 are substantially the same. As described above, in the second magnetoelectric transducers 17a, 17b, and 17c, the magnetic field B1 from the neighboring current path CN1 is measured at a small absolute value with a positive sign.

  The position of the first magnetoelectric transducers 15a and 15b on the X2 side is far from the neighboring current path CN1 on the X1 side, and the magnetic field from the magnetic field B1 from the neighboring current path CN1 is weak. The direction of the sensitivity axis of the first magnetoelectric transducers 15a and 15b and the direction of the magnetic field B1 from the neighboring current path CN1 are nearly orthogonal. However, the component in the sensitivity axis direction of the magnetic field B1 from the neighboring current path CN1 is the same as the sensitivity axis direction. From the above, in the first magnetoelectric transducers 15a and 15b, the magnetic field B1 from the neighboring current path CN1 is measured with a very small absolute value of positive sign.

  The positions of the first magnetoelectric transducers 15c and 15d on the X1 side are slightly close to the neighboring current path CN1 on the X1 side, and the magnetic field from the magnetic field B1 from the neighboring current path CN1 is somewhat strong. The direction of the sensitivity axis of the first magnetoelectric transducers 15a and 15b and the direction of the magnetic field B1 from the neighboring current path CN1 are neither parallel nor orthogonal. However, the component in the sensitivity axis direction of the magnetic field B1 from the neighboring current path CN1 is the same as the sensitivity axis direction. From the above, in the first magnetoelectric transducers 15c and 15d, the magnetic field B1 from the neighboring current path CN1 is measured with a slightly larger absolute value of the positive sign. Moreover, in the present invention, the measured value is increased by arranging “the first magnetoelectric conversion elements 15c and 15d on the X1 side” close to the neighboring current path CN1 side (X1 side).

As described above, the magnetic field B1 from the neighboring current path CN1 is measured with a negative sign by a total of three second magnetoelectric transducers 17d, 17e, 17f. On the other hand, the magnetic field B1 from the adjacent current path CN1 is measured with a positive sign by a total of seven first magnetoelectric transducers 15a, 15b, 15c, 15d and second magnetoelectric transducers 17a, 17b, 17c.
As described above, the second magnetoelectric conversion elements 17d, 17e, 17f measure the magnetic field B1 from the neighboring current path CN1 to a large extent. The magnetic field B1 from the neighboring current path CN1 is measured to be small by the second magnetoelectric conversion elements 17a, 17b, 17c. The magnetic field B1 from the neighboring current path CN1 is measured to be very small by the first magnetoelectric conversion elements 15a and 15b. The magnetic field B1 from the neighboring current path CN1 is measured to be somewhat large by the first magnetoelectric transducers 15c and 15d.

  Therefore, "the sum of the magnetic field B1 from the adjacent current path CN1 measured by the total of three second magnetoelectric transducers 17d, 17e, 17f (sign becomes negative)", and "the total of seven first magnetoelectric conversions" The sum (sign becomes positive) of the magnetic field B1 from the adjacent current path CN1 measured by the elements 15a, 15b, 15c, 15d and the second magnetoelectric conversion elements 17a, 17b, 17c substantially agree with each other. In the present embodiment, all the magnetoelectric transducers (the first magnetoelectric transducers 15a, 15b, 15c, 15d, and the second magnetoelectric transducer are obtained by bringing the positions of the first magnetoelectric transducers 15c and 15d closer to the neighboring current path CN1. The total of the magnetic field B1 from the adjacent current path CN1 measured by the conversion elements 17a, 17b, 17c, 17d, 17e, 17f) can be brought close to zero accurately.

  The first magnetoelectric conversion elements 15a and 15b are in line symmetry with the first magnetoelectric conversion elements 15c and 15d with respect to the center line L2. Therefore, when the first magnetoelectric conversion elements 15c and 15d are brought close to the neighboring current path CN1, the first magnetoelectric conversion elements 15a and 15b move away from the neighboring current path CN1. Therefore, when the magnetic field B1 from the neighboring current path CN1 measured by the first magnetoelectric conversion elements 15c and 15d is increased, the magnetic field B1 from the neighboring current path CN1 measured by the first magnetoelectric conversion elements 15a and 15b is It becomes smaller. That is, considering only the magnitude direction of the change, the proximity current path CN1 measured by the first magnetoelectric conversion elements 15c and 15d is obtained by changing the distance from the center line L2 of the first magnetoelectric conversion elements 15a to 15d. The change in the magnitude of the magnetic field B1 from the above and the change in the magnitude of the magnetic field B1 from the adjacent current path CN1 measured by the first magnetoelectric transducers 15a and 15b cancel each other.

However, as described above, “the magnitude of the magnetic field B1 from the neighboring current path CN1 measured by the first magnetoelectric transducers 15a and 15b” is very small. Therefore, "change in magnitude of the magnetic field B1 from the adjacent current path CN1 measured by the first magnetoelectric conversion elements 15c and 15d" and "nearly current path measured by the first magnetoelectric conversion elements 15a and 15b. The change in the magnitude of the magnetic field B1 from CN1 is not completely offset. Therefore, all the magnetoelectric conversion elements (the first change in the distance from the center line of the first magnetoelectric conversion elements 15a to 15d) Of the magnetic field B1 from the adjacent current path CN1 measured by the magnetoelectric conversion elements 15a, 15b, 15c, 15d and the second magnetoelectric conversion elements 17a, 17b, 17c, 17d, 17e, 17f). .

  As described above, according to the current sensor 101, the influence of the magnetic field from the neighboring current path CN1 can be canceled accurately, and the current in the measured current path CB can be detected accurately. As a result, the size can be further reduced without degrading the detection accuracy of the current sensor 101.

  When the current sensor 101 is sandwiched between two neighboring current paths CN1 and CN2 as shown in FIG. 4, the principle of superposition is established. For this reason, if the current paths CN1, CN, CN2 are arranged at equal intervals, the effects of the magnetic fields of the two adjacent current paths CN1 and CN2 can both be canceled accurately.

  Further, according to the current sensor 101, as shown in FIG. 3, by arranging the first magnetoelectric conversion elements 15a to 15d and the second magnetoelectric conversion elements 17a to 17f, the X direction of the arrangement area of the magnetoelectric conversion elements is obtained. The width can be minimized, and the distance between the measured current path CB and the adjacent current paths CN1 and CN2 can be narrowed. As a result, the wiring board 16 can be miniaturized, that is, the current sensor 101 can be miniaturized. In particular, the width of the left and right arms 18 of the notch 19 can be narrowed.

  Further, according to the current sensor 101, as shown in FIG. 3, by defining the direction SJ of the sensitivity axes of the first magnetoelectric conversion elements 15a to 15d and the second magnetoelectric conversion elements 17a to 17f, the magnetoelectric conversion elements can be obtained. As compared with the case where they are arranged at equal intervals on the circumference (comparative example), when mounting the magnetoelectric conversion elements on the wiring board 16, they can be easily mounted, and The positional relationship between the first magnetoelectric conversion elements 15a to 15d and the second magnetoelectric conversion elements 17a to 17f can be easily designed. Therefore, the accuracy of the mounting angle, the mounting position, and the like of the current path CB to be measured can be enhanced, so that the measurement accuracy can be improved.

  In the current sensor 101, the second magnetoelectric conversion elements 17a to 17f are disposed on the two lines of virtual straight lines L3 and L4 on both sides of the notch 19, and the first magnetoelectric conversion element 15a is formed at four vertices of the virtual rectangle L. It is sufficient to adjust the position of ~ 15d, which facilitates the design for enhancing the measurement accuracy.

The present invention is not limited to the embodiments described above.
That is, those skilled in the art may make various modifications, combinations, subcombinations, and substitutions within the technical scope of the present invention or equivalent components thereof regarding the components of the embodiments described above.

FIG. 6 is a view for explaining a first modified example of the arrangement of the magnetoelectric conversion elements of the current sensor according to the embodiment of the present invention, and is a top view of the wiring board viewed from the Z1 side shown in FIG. .
As shown in FIG. 6, the direction SJ of the sensitivity axis of the first magnetoelectric conversion element 15d is the X1 direction opposite to that of the first magnetoelectric conversion element 15a, and the direction of the sensitivity axis of the first magnetoelectric conversion element 15c. The direction SJ of the sensitivity axis of the second magnetoelectric transducers 17d, 17e, 17f is the same Y1 direction as the second magnetoelectric transducers 17a, 17b, 17c, with SJ being the X2 direction opposite to the first magnetoelectric transducer 15b. It may be

  In this case, in the arithmetic circuit in the subsequent stage, the first magnetoelectric conversion elements 15c and 15d and the second magnetoelectric conversion are performed from the outputs of the first magnetoelectric conversion elements 15a and 15b and the second magnetoelectric conversion elements 17a, 17b and 17c. By subtracting the outputs of the elements 17d, 17e and 17f, components corresponding to the magnetic field of the measured current path CB are accumulated and validated, and components corresponding to the magnetic field of the neighboring current path CN are canceled.

FIG. 7 is a view for explaining a second modification of the arrangement of the magnetoelectric conversion elements of the current sensor according to the embodiment of the present invention, and is a top view of the wiring board viewed from the Z1 side shown in FIG. .
As shown in FIG. 7, when the virtual rectangle L1 centered on the center PP is defined, the first magnetoelectric transducers 15a to 15d are located at four vertices of the virtual rectangle L1.
The second magnetoelectric transducers 17a to 17f are located inside the virtual rectangle L1 and point symmetric with respect to the center PP which is the center of the virtual rectangle L1.

Specifically, as shown in FIG. 6, the second magnetoelectric transducers 17a to 17f are positioned on the imaginary ellipse L5, and the second magnetoelectric transducers 17a to 17c are located on the X2 side with respect to the center line L2. The second magnetoelectric transducers 17d to 17f are located on the X1 side.
The second magnetoelectric conversion elements 17a to 17c and the second magnetoelectric conversion elements 17d to 17f are located in line symmetry with respect to the center line L2.
Also according to the configuration of FIG. 7, the component corresponding to the magnetic field of the neighboring current path CN can be canceled accurately.

  In FIG. 7, the second magnetoelectric transducers 17b and 17e partially extend out of the virtual rectangle L1. However, in the present invention, the position of the magnetoelectric conversion element means the position of the center of the magnetoelectric conversion element. For this reason, even if a part of the package of the second magnetoelectric conversion elements 17a to 17f protrudes from the virtual rectangle L1 connecting the centers of the first magnetoelectric conversion elements 15a to 15d, it is included in the present invention.

  In the above-described embodiment, the case where all of the first magnetoelectric conversion elements 15a to 15d and the second magnetoelectric conversion elements 17a to 17f are disposed on one surface of the wiring board 16 is exemplified. All the magnetoelectric conversion elements may be disposed on the other side.

  In the embodiment described above, the number of magnetoelectric conversion elements is not particularly limited as long as the number of first magnetoelectric conversion elements is four and the number of second magnetoelectric conversion elements is four or more.

  Also, the distance between the magnetoelectric conversion elements is not particularly limited.

  In the embodiment described above, the GMR element is suitably used as the magnetoelectric conversion element, but any magnetic detection element capable of detecting the direction of magnetism may be used, such as a MR (Magneto Resistive) element, an AMR (Anisotropic Magneto Resistive) element, It may be a TMR (Tunnel Magneto Resistive) element, a Hall element or the like. However, in the case of a Hall element or the like, since it differs from the sensitivity axis of the GMR element or MR element, it is necessary to devise mounting in accordance with the sensitivity axis of the Hall element to be used.

Reference Signs List 101 current sensor 11 housing 13 connector 15a to 15d first magnetoelectric conversion element 16 wiring board 17a to 17f second magnetoelectric conversion element 31 case BB central CB to be measured current path CN1, CN2 ... Neighboring current path L1 ... virtual rectangle L2 ... center line L3, L4 ... virtual straight line L5 ... virtual ellipse

Claims (8)

A wiring board,
And a plurality of magnetoelectric conversion elements provided on the wiring board and detecting magnetism generated by a current flowing through the current path to be measured.
The wiring substrate is formed with a notch for positioning the current path to be measured at the center of a virtual rectangle;
The plurality of magnetoelectric conversion elements are
First four magnetoelectric conversion elements located at four vertices of the virtual rectangle;
At least four second magneto-electric transducers at point-symmetrical positions with respect to the center of the virtual rectangle;
The direction of the sensitivity axis of the first magnetoelectric conversion element is orthogonal to the mounting and demounting direction of the measured current path along the notch,
The direction of the sensitivity axis of the second magnetoelectric conversion element is parallel to the mounting and demounting direction,
The directions of the sensitivity axes of the first magnetoelectric conversion elements and the second magnetoelectric conversion elements at point-symmetrical positions with respect to the center of the virtual rectangle are parallel,
A second sensor characterized in that the second magnetoelectric conversion element is located inside the virtual rectangle. The plurality of second magnetoelectric conversion devices on one side and the plurality of second magnetoelectric conversion devices on the other side are disposed in line symmetry with respect to the center line. Current sensor. The plurality of second magnetoelectric conversion elements on one side and the plurality of second magnetoelectric conversion elements on the other side with respect to a center line passing through the center and parallel to the mounting and demounting direction are respectively the centers The current sensor according to claim 2, disposed on a virtual straight line parallel to the line. The current sensor according to claim 2, wherein a long side of the virtual rectangle is parallel to the center line, and a short side thereof is orthogonal to the center line.   The current sensor according to any one of claims 1 to 4, wherein the current path to be measured and the plurality of neighboring current paths are arranged on a straight line at equal intervals. The current sensor according to claim 2, wherein the plurality of second magnetoelectric conversion elements are disposed on a virtual ellipse centered on the center of the virtual rectangle. The first magnetoelectric conversion element and the second magnetoelectric conversion element are arranged such that the sensitivity axes of the first magnetoelectric conversion element and the second magnetoelectric conversion element are directed in one direction along a closed path surrounding the center of the virtual rectangle. The current sensor according to any one of claims 1 to 6, wherein the magnetoelectric conversion element of (1) is disposed. The current sensor according to any one of claims 1 to 7, wherein the first magnetoelectric conversion element and the second magnetoelectric conversion element have the same characteristic.

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