JP6827058B2 - Current sensor - Google Patents

Description

The present invention relates to a current sensor that detects a current flowing in a current path to be measured, and more particularly to a current sensor that detects a current flowing in a current path to be measured by using a magnetic conversion element.

A current sensor that is attached to the current path to be measured and detects the current flowing in the current path to be measured is well known for controlling and monitoring various electronic devices. As a current sensor of this type, a current sensor using a magnetoelectric conversion element such as a Hall element or a magnetoresistive element is known. A conversion element may be used.
In a current sensor using a plurality of magnetic-electric conversion elements in this way, a plurality of magnetic-electric conversion elements are arranged on a virtual circle around the current path to be measured according to the direction of the magnetic field generated around the current path to be measured. Was.

However, if the magnetic-electric conversion element is arranged on the virtual circle as described above, there is a problem that the current sensor cannot be installed when the current sensor becomes large and the distance between the current path to be measured and the neighboring current path is short.

In order to solve such a problem, the current sensor of Patent Document 1 is on a virtual ellipse centered on the position of the current path to be measured and whose short axis is the direction connecting the current path to be measured and the neighboring current path. A plurality of magnetic-electric conversion elements are arranged. Further, in the current sensor of Patent Document 2, a plurality of magnetron conversion elements are arranged 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 of the neighboring current path, and miniaturization can be achieved.

International release WO 2013/128993 International release WO 2015/122064

By the way, in recent years, due to the miniaturization of switchboards and inverters, the distance between adjacent electric wires has become even narrower.
Against this background, the current sensor can be installed even when the distance between the current path to be measured and the neighboring current path is even shorter, and stable current detection is possible without being significantly affected by the external magnetic field of the neighboring current path. There is a request to do.

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

In order to solve the above-mentioned problems of the prior art and achieve the above-mentioned object, the current sensor of the present invention is provided on the wiring board and the magnetism generated by the current flowing through the current path to be measured. A plurality of magnetic and electrical conversion elements to be detected are provided, and a notch for locating the current path to be measured is formed in the center of the virtual rectangle, and the plurality of magnetic and electrical conversion elements are 4 of the virtual rectangle. It has four first magnetic-electric conversion elements located at one apex and at least four second magnetic-electric conversion elements at point-symmetrical positions with respect to the center of the virtual rectangle, and the first magnetic-electric conversion. The direction of the sensitivity axis of the element is orthogonal to the attachment / detachment direction of the current path to be measured along the notch, and the direction of the sensitivity axis of the second magnetic-electric conversion element is parallel to the attachment / detachment direction. The directions of the sensitivity axes of the first magnetic-electric conversion elements and the second magnetic-electric conversion elements located at point-symmetrical positions with respect to the center of the virtual rectangle are parallel, and the second magnetic-electric conversion element is the virtual. It is located inside the rectangle.

According to this configuration, by arranging the second magnetron conversion element inside the virtual rectangle in which the first magnetron conversion element is located at the apex, the first magnetron conversion element and the second magnetron conversion are formed in a straight line. Compared with the case where the elements are arranged, the magnetic field of the neighboring current path generated in the first magnetron conversion element farther from the neighboring current path than the second magnetron conversion element can be strengthened. As a result, the absolute values of the sum of the + components and the sum of the-components according to the magnetic field of the neighboring current path can be matched and canceled with high accuracy.

Preferably, the plurality of the second magnetron conversion elements on one side and the plurality of the second magnetron conversion elements on the other side with respect to the center line passing through the center and parallel to the attachment / detachment direction. , Each arranged on a virtual straight line parallel to the center line.

According to this configuration, the position of the second magnetron conversion element may be adjusted on the virtual straight line, and the design for improving the measurement accuracy becomes easy.

Preferably, the plurality of second magnetron conversion elements on one side and the plurality of second magnetron conversion elements on the other side are arranged line-symmetrically with respect to the center line.

According to this configuration, since the second magnetic field conversion element is arranged line-symmetrically with respect to the center line, the symmetry is maintained and a uniform external magnetic field such as geomagnetism can be canceled with high accuracy.

Preferably, the long side of the virtual rectangle is parallel to the centerline and its short side is orthogonal to the centerline.

According to this configuration, the short side of the virtual rectangle arranged at the apex of the first magnetic-electric conversion element is orthogonal to the central axis, so that it is necessary in the direction orthogonal to the central axis in which the magnetic-electric conversion element is arranged. 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 magnetron conversion elements are arranged on a virtual ellipse centered on the center of the virtual rectangle.

According to this configuration, the position of the second magnetron conversion element may be adjusted on the virtual ellipse centered on the center of the virtual rectangle, and the design for improving the measurement accuracy becomes easy. In addition, the distance between the current path to be measured and the neighboring current path can be narrowed.

Preferably, the first magnetron conversion element is oriented so that the sensitivity axes of the first magnetron conversion element and the second magnetron conversion element point in one direction along a closed path surrounding the center of the virtual rectangle. And the second magnetron conversion element is arranged.

According to this configuration, the direction of the sensitivity axis of the electromagnetic 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 improved.

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

According to the present invention, it is possible to provide a current sensor capable of further miniaturization and stable current detection without being significantly affected by an external magnetic field in a neighboring current path.

It is an exploded perspective view which shows the current sensor which concerns on embodiment of this invention. It is a perspective view which shows the current sensor which concerns on embodiment of this invention. It is a figure for demonstrating the arrangement of the magnetron conversion element of the current sensor which concerns on embodiment of this invention, and is the top view of the wiring board seen from the Z1 side shown in FIG. It is a figure for demonstrating the neighborhood current path of the current sensor shown in FIG. It is a figure for demonstrating the influence of the magnetic field from the neighborhood current path CN1 shown in FIG. 4 in the current sensor shown in FIG. It is a figure for demonstrating the 1st modification of the arrangement of the magnetron conversion element of the current sensor which concerns on embodiment of this invention, and is the top view of the wiring board seen from the Z1 side shown in FIG. It is a figure for demonstrating the 2nd modification of the arrangement of the magnetron conversion element of the current sensor which concerns on embodiment of this invention, and is the top view of the wiring board seen from the 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 the current sensor 101 according to the embodiment of the present invention. FIG. 3 is a diagram 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 magnetic-electric conversion elements 15 for detecting magnetism generated when a current flows through a current path CB to be measured, and a plurality of magnetic-electric conversion elements 15. It is configured to include a wiring board 16 on which the magnetic-electric conversion element 15 is arranged. Further, the current sensor 101 includes a housing 11 having a storage portion 11s for accommodating the wiring board 16, a connector 13 having an extraction terminal 13t for extracting an electric signal from the magnetic-electric conversion element 15, and a current path CB to be measured. It is provided with a holding member 14 for fixing and holding the.

The housing 11 is made of a synthetic resin material. The housing 11 is composed of a box-shaped case 31 having an opening at the top and a plate-shaped cover 41 that closes the opening of the case 31, and a storage portion for storing the wiring board 16 inside the case 31. 11s is formed.

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

In the present embodiment, the back wall 32a of the recess 32 is formed to be curved in an arc shape so as to correspond to the outer peripheral surface of the cylindrical current path CB to be measured. Further, notches 32c for locking the free end side of the clip spring 14K are formed at positions facing each other on the facing inner side wall 32b of the case 31 connected to the back wall 32a.

The notch 32c is notched downward from the upper end side of the inner side wall 32b, and the end surface on the entrance side is formed so as to incline outward. The current path CB to be measured is sandwiched by a clip spring 14K projecting from the notch 32c into the recess 32 with the back side of the outer peripheral surface in contact with the back wall 32a of the recess 32. It is held against the housing 11. The position sandwiched between the back wall 32a of the recess 32 and the clip spring 14K is the central PP of the current path CB to be measured with respect to the housing 11. In the present embodiment, the central PP is the central PP of the virtual rectangle L described later.

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

The holding member 14 is a member for fixing and holding the measured current path CB, and the clip spring 14K that sandwiches and holds the outer edge of the measured current path CB and the measured current path CB are arranged in the central PP. After that, it is provided with a pushing member 14H that presses the clip spring 14K.

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

A multilayer printed wiring board (PCB) is used for the wiring board 16, 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 in a size that can be stored in the storage portion 11s of the case 31, and a notch 19 through which the current path CB to be measured is inserted and arranged is formed on one side portion thereof. That is, the wiring board 16 is formed in a shape similar to the bottom surface portion of the storage portion 11s, and a notch portion 17 having a complementary shape is formed with the recess 32 of the case 31.

As shown in FIGS. 1 and 3, a plurality of (10) magnetron conversion elements 15 are arranged in the vicinity of the notch 19 of the wiring board 16 and in the vicinity of the side portion facing the side portion in which the notch 19 is formed. Is provided with a connector 13. The detailed arrangement position of the magnetron conversion element 15 will be described later.

The connector 13 includes a plurality of terminals that are electrically connected to a mating connector (not shown), and has a take-out terminal 13t in the plurality of terminals for extracting an electric signal from the magnetron conversion element 15. ing. Further, the connector 13 includes an insulating base 13K for fitting with a mating connector (not shown). The insulating substrate 13K is formed in a box shape with an opening at the upper side, and a plurality of terminals including the take-out terminal 13t are held and stored in a box shape in which the terminals are insulated from each other. In the present embodiment, the connector 13 is used to extract the electric signal from the magnetron conversion element 15, but the connector 13 is not limited to the connector 13, and for example, a flexible printed circuit board (FPC) or the like may be used. good.

The magnetoelectric conversion element 15 is a current sensor element that detects magnetism generated when a current flows in the current path CB to be measured. For example, a magnetic detection element (GMR (Giant Magneto Resistive)) using a giant magnetoresistive effect. It is possible to use an element). Although detailed illustration of the magnetron conversion element 15 is omitted for the sake of simplicity, the GMR element is manufactured on a silicon substrate, and then the cut-out chip is packaged with a thermosetting synthetic resin to obtain a signal. The lead terminal for taking out is electrically connected to the GMR element. Then, the lead terminal is soldered to the wiring board 16.

As shown in FIG. 3, in the current sensor 101, four first magnetron conversion elements 15a, 15b, 15c, 15d and six second magnetron conversion elements are formed around the central PP of the current path CB to be measured. Elements 17a, 17b, 17c, 17d, 17e, 17f are arranged.
The first magnetron conversion elements 15a, 15b, 15c, 15d and the six second magnetron conversion elements 17a, 17b, 17c, 17d, 17e, 17f have the same magnetron conversion characteristics. This facilitates the design for improving 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 current path CB to be measured. The notch 19 has a shape capable of locating the center of the current path CB to be measured 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 magnetron conversion elements 15a and 15b and the second magnetron conversion elements 17a and 17b , 17c are arranged. Further, the first magnetron conversion elements 15c and 15d and the second magnetron conversion elements 17d, 17e and 17f are arranged 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. ing.

As shown in FIG. 3, when the virtual rectangle L1 centered on the center PP is defined, the first magnetron conversion elements 15a to 15d are located at the four vertices of the virtual rectangle L1.
Specifically, as shown in FIG. 3, when a center line L2 that passes through the center PP and is parallel to the attachment / detachment direction (Y1-Y2 direction) along the notch 32c of the current path CB to be measured is defined, it is a virtual rectangle. The long side of L1 is parallel to the center line L2, and its short side is orthogonal to the center line L2.

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

The first magnetron conversion element 15a, the second magnetron conversion elements 17a, 17b, 17c and the first magnetron conversion element 15b have the first magnetron conversion element 15c, respectively, with respect to the central PP of the first rectangle L1. It is arranged point-symmetrically with the second magnetron conversion elements 17d, 17e, 17f and the first magnetron conversion element 15d, respectively.

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

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

On the other hand, in the case of the arrangement of the magnetron conversion element 15 according to the present embodiment, three second magnetron conversion elements 17a, 17b, 17c are arranged on the long side L31 of the second rectangle L3, and three pieces are arranged. The second magnetron conversion elements 17f, 17e, 17d are arranged on the long side L32 of the second rectangle L3.
Therefore, the distance in the X1-X2 direction (X direction) required for arranging the second magnetron conversion elements 17a, 17b, 17c and the second magnetron 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 can be narrowed.
As a result, the arrangement region of the magnetron conversion element can be reduced especially in the direction orthogonal to the forming direction of the notch 19 (X1-X2 direction), and the wiring substrate 16 can be downsized, that is, the current sensor 101 can be downsized. Is. In particular, in an application where a plurality of current paths are provided at intervals as narrow as possible, such as a switchboard, it is important that the widths of the left and right arm portions 18 of the notch 19 can be narrowed.

The orientation SJ of the sensitivity axes (directions for sensing magnetism) of the first magnetic-electric conversion elements 15a to 15d is parallel to the short side of the virtual rectangle L1, that is, the attachment / detachment direction of the current path CB to be measured to the notch 32c Y1-Y2. Is orthogonal to. This facilitates a design that enhances the measurement accuracy of the current sensor 101.
Specifically, the directions SJ of the sensitivity axes of the first magnetron conversion elements 15a and 15c are in the X1 direction, and the directions SJ of the sensitivity axes of the first magnetron conversion elements 15d and 15a are in the X2 direction.
The direction SJ of the sensitivity axes of the second magnetron conversion elements 17a, 17b, 17c is in the Y1 direction, and the direction SJ of the sensitivity axes of the second magnetron conversion elements 17d, 17e, 17f is in the Y2 direction.
In the first magnetron conversion elements 15a to 15d and the second magnetron conversion elements 17a to 17f, the direction SJ of their sensitivity axes is a closed path surrounding the center PP of the virtual rectangle L1 which is the center of the current path CB to be measured. It is arranged so as to face in one direction (clockwise in this embodiment) along the line.

As a result, in the second magnetron conversion elements 17a, 17b, 17, the directions SJ of the sensitivity axes are opposite to those of the second magnetron conversion elements 17d, 17e, 17f located at point-symmetrical positions about the center PP.
In the calculation circuit in the latter stage, the components corresponding to the magnetic field of the current path CB to be measured are accumulated by adding the outputs of the first magnetron conversion elements 15a to 15d and the outputs of the second magnetron conversion elements 17a to 17f. To activate and cancel the component corresponding to the magnetic field of the neighboring current path CN.

FIG. 4 is a diagram for explaining a nearby current path of the 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 magnetron conversion elements 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 directions of the sensitivity axes of the second magnetron conversion elements 17d, 17e, 17f and the direction of the magnetic field B1 from the neighboring current path CN1 are almost parallel. However, the directions of the sensitivity axes of the second magnetron conversion elements 17d, 17e, and 17f and the directions of the magnetic field B1 from the neighboring current path CN1 are substantially opposite directions. That is, the sensitivity axial component of the magnetic field B1 from the neighboring current path CN1 is opposite to the sensitivity axial direction. From the above, in the second magnetron conversion elements 17d, 17e, 17f, the magnetic field B1 from the neighboring current path CN1 is measured with a large absolute value of a negative sign.

The positions of the second electromagnetic conversion elements 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 axes of the second magnetron conversion elements 17a, 17b, 17c and the direction of the magnetic field B1 from the neighboring current path CN1 are almost parallel. The direction of the sensitivity axes of the second magnetron conversion elements 17a, 17b, 17c and the direction of the magnetic field B1 from the neighboring current path CN1 are substantially the same direction. From the above, in the second magnetron conversion elements 17a, 17b, 17c, the magnetic field B1 from the neighboring current path CN1 is measured with a small absolute value of a positive sign.

The positions of the first magnetic electroconversion elements 15a and 15b 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 axes of the first magnetron conversion elements 15a and 15b and the direction of the magnetic field B1 from the neighboring current path CN1 are close to orthogonal. However, the sensitivity axial component of the magnetic field B1 from the neighboring current path CN1 is the same as the sensitivity axial direction. From the above, in the first magnetron conversion elements 15a and 15b, the magnetic field B1 from the neighboring current path CN1 is measured with a very small absolute value of a positive sign.

The positions of the first magnetic electric conversion elements 15c and 15d on the X1 side are slightly closer 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 slightly stronger. The orientation of the sensitivity axes of the first magnetron conversion elements 15a and 15b and the orientation of the magnetic field B1 from the neighboring current path CN1 are neither parallel nor orthogonal. However, the sensitivity axial component of the magnetic field B1 from the neighboring current path CN1 is the same as the sensitivity axial direction. From the above, in the first magnetron conversion elements 15c and 15d, the magnetic field B1 from the neighboring current path CN1 is measured with a slightly larger absolute value of a positive sign. Moreover, in the present invention, the measured value is increased by arranging the "first magnetron 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 by a total of three second magnetron conversion elements 17d, 17e, 17f with a negative sign. On the other hand, the magnetic field B1 from the neighboring current path CN1 is measured with a positive code by the total of seven first magnetron conversion elements 15a, 15b, 15c, 15d and the second magnetron conversion elements 17a, 17b, 17c.
As described above, the magnetic field B1 from the neighboring current path CN1 is largely measured by the second magnetron conversion elements 17d, 17e, 17f. The magnetic field B1 from the neighboring current path CN1 is measured small by the second magnetron conversion elements 17a, 17b, 17c. The magnetic field B1 from the neighboring current path CN1 is measured very small by the first magnetron conversion elements 15a and 15b. The magnetic field B1 from the neighboring current path CN1 is measured slightly larger by the first magnetron conversion elements 15c and 15d.

Therefore, "the total of the magnetic fields B1 from the neighboring current paths CN1 measured by the total of three second magnetron conversion elements 17d, 17e, 17f (the sign becomes negative)" and "the total of seven first magnetron conversions". The sum of the magnetic fields B1 from the neighboring current paths CN1 measured by the elements 15a, 15b, 15c, 15d and the second magnetron conversion elements 17a, 17b, 17c (the sign becomes positive) ”generally agrees. In the present embodiment, by moving the positions of the first magnetron conversion elements 15c and 15d closer to the neighboring current path CN1, all the magnetron conversion elements (first magnetron conversion elements 15a, 15b, 15c, 15d and second magnetron) are used. The total of the magnetic fields B1 from the neighboring current path CN1 measured by the conversion elements 17a, 17b, 17c, 17d, 17e, 17f) can be accurately approached to 0.

The first magnetron conversion elements 15a and 15b are in line-symmetrical positions with respect to the first magnetron conversion elements 15c and 15d and the center line L2. Therefore, when the first magnetron conversion elements 15c and 15d are brought closer to the neighboring current path CN1, the first magnetron conversion elements 15a and 15b are moved away from the neighboring current path CN1. Therefore, when the magnetic field B1 from the neighboring current path CN1 measured by the first magnetron conversion elements 15c and 15d is increased, the magnetic field B1 from the neighboring current path CN1 measured by the first magnetron conversion elements 15a and 15b becomes large. It becomes smaller. That is, considering only the magnitude of the change, the "neighboring current path CN1 measured by the first magnetron conversion elements 15c and 15d" due to changing the distance from the center line L2 of the first magnetron 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 neighboring current path CN1 measured by the first magnetron conversion elements 15a and 15b" cancel each other out.

However, as described above, the "magnitude of the magnetic field B1 from the neighboring current path CN1 measured by the first magnetron conversion elements 15a and 15b" is very small. Therefore, "change in the magnitude of the magnetic field B1 from the neighboring current path CN1 measured by the first magnetron conversion elements 15c and 15d" and "the neighborhood current path measured by the first magnetron conversion elements 15a and 15b". The "change in the magnitude of the magnetic field B1 from CN1" is not completely canceled. Therefore, by changing the distance from the center line of the first magnetron conversion elements 15a to 15d, all the magnetron conversion elements (first). The total of the magnetic fields B1 from the neighboring current path CN1 measured by the magnetron conversion elements 15a, 15b, 15c, 15d and the second magnetron conversion elements 17a, 17b, 17c, 17d, 17e, 17f) can be made almost 0. ..

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

When the current sensor 101 is sandwiched between two neighboring current paths CN1 and neighboring current paths CN2 as shown in FIG. 4, the superposition theory holds. Therefore, if the current paths CN1, CN, and CN2 are arranged at equal intervals, the effects of the magnetic fields of the two neighboring current paths CN1 and the neighboring current paths CN2 can be canceled out with high accuracy.

Further, according to the current sensor 101, as shown in FIG. 3, the first magnetron conversion elements 15a to 15d and the second magnetron conversion elements 17a to 17f are arranged, so that the arrangement area of the magnetron conversion elements is in the X direction. The width can be minimized, and the distance between the current path CB to be measured and the neighboring 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 arm portions 18 of the notch 19 can be narrowed.

Further, according to the current sensor 101, as shown in FIG. 3, the magnetron conversion element is formed by defining the direction SJ of the sensitivity axes of the first magnetron conversion elements 15a to 15d and the second magnetron conversion elements 17a to 17f. Compared with the case where they are arranged at equal intervals on the circumference (comparative example), when each magnetron conversion element is mounted on the wiring board 16, it can be easily mounted, and the wiring board 16 and the first The positional relationship between the magnetron conversion elements 15a to 15d of 1 and the magnetron conversion elements 17a to 17f of the second magnetron conversion elements 17a to 17f can be easily designed. Therefore, the accuracy of the mounting angle, mounting position, etc. of the current path CB to be measured can be improved, so that the measurement accuracy can be improved.

In the current sensor 101, the second magnetic-electric conversion elements 17a to 17f are arranged on the two rows of virtual straight lines L3 and L4 on both sides of the notch 19, and the first magnetic-electric conversion elements 15a are formed at the four vertices of the virtual rectangle L. The position of ~ 15d may be adjusted, and the design for improving the measurement accuracy becomes easy.

The present invention is not limited to the embodiments described above.
That is, one of ordinary skill in the art may make various changes, combinations, sub-combinations, and alternatives with respect to the components of the above-described embodiments within the technical scope of the present invention or the equivalent thereof.

FIG. 6 is a diagram for explaining a first modification of the arrangement of the magnetron conversion element of the current sensor according to the embodiment of the present invention, and is a top view of the wiring board seen from the Z1 side shown in FIG. ..
As shown in FIG. 6, the direction SJ of the sensitivity axis of the first magnetron conversion element 15d is set to the X1 direction opposite to that of the first magnetron conversion element 15a, and the direction of the sensitivity axis of the first magnetron conversion element 15c. The SJ is in the X2 direction opposite to that of the first magnetron conversion element 15b, and the direction of the sensitivity axes of the second magnetron conversion elements 17d, 17e, 17f is the same Y1 direction as the second magnetron conversion elements 17a, 17b, 17c. May be.

In this case, in the subsequent arithmetic circuit, from the outputs of the first magnetron conversion elements 15a and 15b and the second magnetron conversion elements 17a, 17b and 17c, the first magnetron conversion elements 15c and 15d and the second magnetron conversion By subtracting the outputs of the elements 17d, 17e, and 17f, the components corresponding to the magnetic field of the current path CB to be measured are accumulated and activated, and the 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 magnetron conversion element of the current sensor according to the embodiment of the present invention, and is a top view of the wiring board seen 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 magnetron conversion elements 15a to 15d are located at the four vertices of the virtual rectangle L1.
Further, the second magnetron conversion elements 17a to 17f are located inside the virtual rectangle L1 and are point-symmetrical to the center PP which is the center of the virtual rectangle L1.

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

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

Further, in the above-described embodiment, the case where all of the first magnetron conversion elements 15a to 15d and the second magnetron conversion elements 17a to 17f are arranged on one surface of the wiring board 16 has been illustrated, but some of them or All magnetron conversion elements may be arranged on the other surface.

Further, in the above-described embodiment, the number of magnetron-converting elements is not particularly limited as long as the first magnetron-converting element has four and the second magnetron-converting element has four or more.

Further, the distance between the magnetron conversion elements is not particularly limited.

Further, in the above-described embodiment, the GMR element is preferably used as the magnetoelectric conversion element, but any magnetic detection element capable of detecting the direction of magnetism may be used, and MR (Magneto Resistive) element, 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 is different from the sensitivity axis of the GMR element or MR element, it is necessary to devise the mounting according to the sensitivity axis of the Hall element to be used.

101 ... Current sensor 11 ... Housing 13 ... Connector 15a to 15d ... First magnetic-electric conversion element 16 ... Wiring board 17a to 17f ... Second magnetic-electric conversion element 31 ... Case BB ... Center CB ... Current path to be measured CN1, CN2 ... Neighborhood current path L1 ... Virtual rectangle L2 ... Center line L3, L4 ... Virtual straight line L5 ... Virtual ellipse

Claims (8)

Wiring board and
It is provided on the wiring board and is provided with a plurality of magnetic-electric conversion elements for detecting magnetism generated by a current flowing through a current path to be measured.
A notch for locating the current path to be measured is formed in the center of the virtual rectangle on the wiring board.
The plurality of magnetron conversion elements
When viewed from the extending direction of the current path to be measured, the four first magnetron conversion elements whose centers are located at each of the four vertices of the virtual rectangle,
When viewed from the extending direction of the current path to be measured , it has at least four second magnetron conversion elements whose centers are point-symmetrical with respect to the center of the virtual rectangle.
The direction of the sensitivity axis of the first magnetron conversion element is orthogonal to the attachment / detachment direction of the current path to be measured along the notch.
The direction of the sensitivity axis of the second magnetron conversion element is parallel to the attachment / detachment direction.
The directions of the sensitivity axes of the first magnetron conversion elements and the second magnetron conversion elements located at point-symmetrical positions with respect to the center of the virtual rectangle are parallel.
A current sensor characterized in that , when viewed from the extending direction of the current path to be measured , the centers of the second magnetron conversion elements are located inside the virtual rectangle. The first aspect of claim 1, wherein the plurality of second magnetron conversion elements on one side and the plurality of second magnetron conversion elements on the other side are arranged line-symmetrically with respect to the center line. Current sensor. The plurality of second magnetic-electric conversion elements on one side and the plurality of second magnetic-electric conversion elements on the other side of the center line passing through the center and parallel to the attachment / detachment direction are the centers, respectively. The current sensor according to claim 2, which is arranged on a virtual straight line parallel to the line. The current sensor according to claim 2, wherein the long side of the virtual rectangle is parallel to the center line, and the 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 a plurality of neighboring current paths are arranged in a straight line at equal intervals. The current sensor according to claim 2, wherein the second magnetron conversion element is arranged on a virtual ellipse centered on the center of the virtual rectangle. The first magnetron conversion element and the second magnetron conversion element so that the sensitivity axes of the first magnetron conversion element and the second magnetron conversion element point 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 magnetron conversion element is provided. The current sensor according to any one of claims 1 to 7, wherein the first magnetron conversion element and the second magnetron conversion element have the same characteristics.

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