JP2015158474A - Current sensing coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current sensing coil which is less susceptible to influence of external magnetic fields, allows for increasing the number of windings of toroidal coils using a circuit board of a conventional size, and has a reduced number of through-holes, which improves yield.SOLUTION: A current sensing coil has a circuit substrate having an opening and comprising a plurality of conductive layers and a plurality of insulating layers alternately laminated, and toroidal coils formed surrounding the opening, the toroidal coils being a forward wound coil and a reverse wound coil, which are wound in opposite directions with respect to a magnetic field parallel to a lamination direction of the circuit board. Through-holes 61, 81 are formed alternately along two circles having large and small diameters at respective predetermined intervals. Pairs of portions 11a and 31a, 11b and 21b, 21a and 41a, 31b and 41b of conductive patterns formed on the plurality of conductive layers to form the forward wound coil and reverse wound coil overlap with each other when viewed in the lamination direction of the circuit board.

Description

The present invention relates to a current detection coil used as a current detection sensor in a distribution board or the like, and more particularly to a Rogowski coil.

Rogowski coils are used as current detection sensors in distribution boards, etc.
Energy saving is progressing in ED bulbs and other electrical equipment, and higher sensitivity is required so that less current can be detected. By the way, since the Rogowski coil is coreless, it has the merits that it does not saturate magnetically and there is no heat generation due to magnetic loss and no hysteresis error. Have.

The influence of the external magnetic field will be described with reference to FIG. In FIG. 11, (a)
Shows a configuration of a general CT (current transformer) in which a toroidal coil is wound around a toroidal core made of a magnetic material, and (b) shows a configuration of a coreless Rogowski coil. Further, (c) shows an area surrounded by a general CT with respect to an external magnetic field in a direction perpendicular to the paper surface. (D)
Indicates the area enclosed by the Rogowski coil with respect to the external magnetic field in the direction perpendicular to the paper surface.

As shown in FIG. 11 (a), in general CT, a conductor is spirally wound around a toroidal core and wound around the toroidal direction to finish winding, so a direction perpendicular to the toroidal direction (that is, paper surface) Is equivalent to a one-turn coil. Therefore, as shown in FIG. 11C, for an external magnetic field in a direction perpendicular to the toroidal direction, the cross section perpendicular to the toroidal direction of the toroidal coil is directly affected by the external magnetic field (left oblique hatching). Become. However, since a general CT has a magnetic core, the output S due to the magnetic field to be measured passing through the inside of the toroidal core is much larger than the noise N due to the external magnetic field. It doesn't matter. However, since the Rogowski coil is coreless, the output S due to the magnetic field to be measured is small and is easily affected by the external magnetic field, so that a decrease in S / N becomes a problem. Therefore, as shown in FIG. 11 (b), the conductor is spirally wound, and after making a round in the toroidal direction, the central portion of the toroidal coil is rewound by one turn in the opposite direction. Therefore, as shown in FIG. 11 (d), for an external magnetic field perpendicular to the toroidal direction, the cross section perpendicular to the toroidal direction of the toroidal coil in the winding advance direction is rewound for one turn in the unwinding direction. The area of the region (right oblique hatching) that is offset by the cross section of the coil and affected by the external magnetic field is small.

As a technique for increasing the S / N ratio of the Rogowski coil, it is conceivable to increase the number of turns of the toroidal coil. However, for example, a Rogowski coil of a type that forms a coil with conductive patterns and through holes (via holes) on both sides of a circuit board as described in Patent Document 1, the diameter of a processable through hole, the outer diameter of a land, and the like Due to this limitation, the number of turns of the coil is limited. Therefore, the Rogowski coil described in Patent Document 1 is further devised in the conductive pattern formed on the circuit board surface so as to cancel the influence of the external magnetic field.

FIG. 12 shows a conventional Rogowski coil 201 described in Patent Document 1, and FIG. 13 shows a conductive pattern and a through hole seen through in the stacking direction of the circuit board. In FIG. 12, the signs of the winding advance coil and the rewinding coil are shown at positions apart from each other in order to avoid the intersection of the lead wires.

In this Rogowski coil 201, a toroidal coil is continuously formed in double in the winding direction and the unwinding direction, and 1 in the winding coil as viewed from the direction perpendicular to the circuit board 202 (the direction in which the current to be measured flows). Area S1 for turn and area S for one turn of rewinding coil
The conductive pattern is formed so that the areas of 2 are substantially equal. As a result, the influence of the winding coil from the external magnetic field is offset by the influence of the unwinding coil from the external magnetic field, and the S / N is further increased by reducing the noise component.

More specifically, the annular circuit board 202 has through holes 211... On the inner circumferential side at regular intervals on the same circumference along a circular opening 203 that penetrates the conductor through which the current to be measured flows. 231 ... are formed. Further, on the outer peripheral portion of the circuit board 202, through holes 221... 241... 241. On the surface of the circuit board 202, the conductive pattern 2 that extends radially from the through hole 211 constituting the winding coil toward the outer periphery and is dog-legged to the right near the outer periphery.
51 is formed. There is a through hole 2 at the tip of the conductive pattern 251 where the right dog leg is formed.
21 is formed. On the back surface of the circuit board 202, a conductive pattern that extends radially from the through hole 212 adjacent to the right of the through hole 211 toward the outer periphery and left dog leg (right dog leg when viewed from the back side) in the vicinity of the outer periphery. 252 is formed and further connected to the through hole 221. In this way, the coil is wound up by the conductive pattern 251 on the front surface, the through hole 221, the conductive pattern 252 on the back surface, and the through hole 212.
A turn is formed. Such a conductive pattern and through-hole have an annular circuit board 202.
It is formed so as to make a round in the toroidal direction and forms a winding advance coil.

On the surface of the circuit board 202, a conductive pattern 261 that extends simply radially toward the outer peripheral portion is formed from the through hole 231 constituting the rewinding coil, and a through hole 241 is formed at the tip of the conductive pattern 261. ing. The through hole 241 is formed on the inner concentric circle of the two concentric circles on the outer peripheral portion of the circuit base 202. Circuit board 2
On the back surface of 02, a short conductive pattern 262 is formed from the through hole 241 to the left dog leg (right dog leg when viewed from the back side) toward the outer concentric circle of the two concentric circles on the outer periphery of the circuit board 202, Through hole 242 formed on the outer concentric circumference
It is connected to the. On the surface of the circuit board 202, a short conductive pattern 263 is formed from the through hole 242 to the left concentric circle out of the two concentric circles on the outer periphery of the circuit board 202, and formed on the outer concentric circumference. Connected to the through hole 243. On the back surface of the circuit board 202, a conductive pattern 264 that simply extends radially from the through hole 243 toward the inner peripheral portion is formed and connected to the through hole 232. Thus, the conductive pattern 261 on the front surface, the through hole 241, the conductive pattern 262 on the back surface, the through hole 242, the conductive pattern 263 on the front surface, and the through hole 243.
Then, one turn of the rewinding coil is formed by the conductive pattern 264 on the back surface and the through hole 232. Such conductive patterns and through-holes are formed on the annular circuit board 202 so as to make a round in the toroidal direction, thereby forming a rewinding coil.

As is apparent from FIGS. 12 and 13, the circuit board 202 has only two conductive layers on which conductive patterns are formed, and the conductive patterns are formed on the back surface of the portions where the conductive patterns are formed on the front surface. Not the other way around, and vice versa. Therefore, the number of conductive patterns cannot be increased, and as a result, there is a limit to increasing the number of turns of the toroidal coil. Further, since the conductive pattern of the rewinding coil winds up and overcomes the conductive pattern of the coil, three through holes are required, so the number of through holes in the outer peripheral portion of the annular circuit board 202 is increased and the yield is reduced. It is the cause.

Further, as shown in FIG. 13, with respect to the rewinding coil, the winding direction of the coil that goes over the conductive pattern of the winding advance coil is reverse to the original magnetic field to be measured. Specifically, with respect to the magnetic field to be measured indicated by the arrow X, the conductive pattern 264, the through hole 2
31, one turn of the coil formed by the conductive pattern 261 and the through hole 241 and the winding direction of one turn of the coil formed by the through hole 241, the conductive pattern 262, the through hole 241, the conductive pattern 263, and the through hole 243 It is reversed. For this reason, the cross-sectional area of the reverse winding portion acts in the direction of canceling the current flowing through the rewinding coil as a signal, which is one of the causes of the S / N reduction.

JP 2007-155427 A

The present invention has been made in order to solve the above-described problems of the conventional example. The circuit having the same size as that of the conventional circuit is offset while the influence of the winding coil from the external magnetic field is offset by the influence of the winding coil from the external magnetic field. To provide a coil for current measurement that can increase the number of turns of a toroidal coil using a substrate, and further improve the yield by reducing the number of through-holes and the design of a coil with high output and high sensitivity. Objective.

In order to achieve the above object, a coil for current measurement according to the present invention has an opening through which a conductor through which a current to be measured flows penetrates at the center, and is formed by laminating a plurality of conductive layers and a plurality of insulating layers. A coil for current measurement in which a toroidal coil is formed on a circuit board so as to surround the opening, and a winding coil and a winding coil whose winding directions are opposite to each other with respect to a magnetic field parallel to the stacking direction of the circuit board. Each of the winding advance coil and the rewinding coil has a coil, and each of the plurality of conductive holes surrounds the opening, and has two through holes formed at predetermined intervals on two circumferences each having a large and small diameter. Conductive patterns formed on the layers and forming the winding advance coil and the rewinding coil overlap each other as seen through from the stacking direction of the circuit board.

Conductive patterns that form the winding advance coil, conductive patterns that form the rewinding coil, or conductive patterns that form the winding advance coil and the rewinding with respect to a magnetic field orthogonal to the stacking direction of the circuit board. The conductive patterns forming the coil are preferably overlapped so that currents flow in opposite directions.

The winding advance coil is formed by a winding advance conductive pattern formed in two conductive layers forming the circuit board and a through hole that electrically connects the winding advance conductive pattern formed in the two conductive layers. A toroidal coil, wherein the rewinding coil electrically connects a rewinding conductive pattern formed on the other two conductive layers forming the circuit board and a rewinding conductive pattern formed on the other two conductive layers. It is preferable that the toroidal coil is formed by a through hole connected to the.

Alternatively, the winding advance coil is formed by a winding advance conductive pattern formed in two conductive layers forming the circuit board and a through hole that electrically connects the winding advance conductive pattern formed in the two conductive layers. Preferably, the rewinding coil is a planar coil that is formed on another conductive layer that forms the circuit board and is formed so as to substantially go around the opening.

Two concentric circles having a plurality of through-holes formed in the stacking direction of the circuit board and electrically connecting the conductive patterns formed in the plurality of conductive layers have different diameters on the inner peripheral side close to the opening. It is preferable that every other one is formed at a predetermined interval on the circumference, and is formed at a predetermined interval on a single circumference on the outer peripheral side far from the opening.

The circuit board is preferably formed by stacking four conductive layers and three insulating layers, and all the through holes are formed so as to penetrate the four conductive layers and the three insulating layers.

Of the three insulating layers, the central insulating layer is preferably thicker than the other two insulating layers.

The first lead wire portion connected to the start point portion of the winding advance coil and the second lead wire portion connected to the end point portion of the rewind coil are formed in a pattern in which currents flow in opposite directions. Preferably it is.

It is preferable that the first lead line portion and the second lead line portion are respectively formed in different conductive layers of the circuit board.

According to the present invention, each of the winding advance coil and the rewinding coil surrounds an opening, and every other through hole is formed on the two circumferences having large and small diameters at predetermined intervals. This makes it possible to design a coil with high output and high sensitivity. In addition, the winding directions of the winding advance coil and the rewinding coil are opposite to each other, and the conductive patterns that respectively form the winding advance coil and the rewinding coil are seen through from the direction parallel to the stacking direction of the circuit board and overlap each other. Therefore, with respect to the magnetic field perpendicular to the circuit board stacking direction, currents flowing in the opposite direction flow in the overlapping parts, thereby canceling the influence of the external magnetic field, so that it is perpendicular to the circuit board stacking direction. A decrease in S / N due to a magnetic field can be prevented. Furthermore, since the conductive patterns that respectively form the winding advance coil and the rewinding coil are seen through from the direction parallel to the stacking direction of the circuit board, they overlap each other. Compared to a conventional example in which a conductive pattern is not formed (and vice versa), the number of turns of a toroidal coil can be increased using a circuit board of the same size. Further, since the conductive pattern of the winding advance coil and the conductive pattern of the rewinding coil are formed in different conductive layers, an extra through hole is provided to overcome the conductive pattern of the winding advance coil and the conductive pattern of the rewinding coil. This is not necessary, and the total number of through holes in the circuit board does not increase, and it is possible to prevent a decrease in yield.

1 is a front view showing a circuit board on which a Rogowski coil according to a first embodiment of the present invention is formed. The front view which shows the 1st conductive pattern formed in the 1st conductive layer of the circuit board in 1st Embodiment. The front view which shows the 2nd conductive pattern formed in the 2nd conductive layer of the circuit board in 1st Embodiment. The front view which shows the 3rd conductive pattern formed in the 3rd conductive layer of the circuit board in 1st Embodiment. The front view which shows the 4th conductive pattern formed in the 4th conductive layer of the circuit board in 1st Embodiment. The perspective view for demonstrating that the conductive pattern which forms the winding advance coil and rewinding coil in 1st Embodiment has overlapped so that an electric current may flow into the mutually opposite direction. The front view which shows the 1st conductive pattern formed in the 1st conductive layer of the circuit board in 2nd Embodiment. The front view which shows the 2nd conductive pattern formed in the 2nd conductive layer of the circuit board in 2nd Embodiment. The front view which shows the 3rd conductive pattern formed in the 3rd conductive layer of the circuit board in 2nd Embodiment. The front view which shows the 4th conductive pattern formed in the 4th conductive layer of the circuit board in 2nd embodiment. Comparison explanatory drawing of the influence by the external magnetic field of general CT and Rogowski coil. The top view which shows the conventional Rogowski coil. The perspective view which shows the structure of the conductive pattern and through-hole of the conventional Rogowski coil.

(First embodiment)
A Rogowski coil type current measurement coil according to the first embodiment of the present invention will be described. FIG. 1 shows a circuit board on which a Rogowski coil 1 according to the first embodiment is formed. In addition,
In FIG. 1, only the conductive patterns of the first conductive layer (solid line) and the second conductive layer (broken line) are shown for easy understanding. 2 to 5 show conductive patterns of the first to fourth conductive layers, respectively.

The Rogowski coil 1 according to the first embodiment is formed on a circuit board 2 formed by alternately laminating four conductive layers and three insulating layers. As shown in FIG. A circular opening 3 for penetrating a conductor through which a current to be measured flows is formed at the center. Further, along the circular opening 3, through holes 61..., 81... On the inner peripheral side are formed every other predetermined interval on the circumference of the two concentric circles C 1 and C 2. Further, in the outer peripheral portion of the circuit board 2, through holes 51,... 71,.
Is formed. Each through hole is formed so as to penetrate through four conductive layers and three insulating layers.

In the first embodiment, the winding advance coil and the rewinding coil are each formed as a toroidal coil. The winding coil mainly includes the second conductive pattern 20 of the second conductive layer,
4th conductive pattern 40 of the 4th conductive layer, outer peripheral side through-hole 51 ..., and it is comprised by the through-hole 61 ... formed on the concentric circumference with a small diameter among inner peripheral side through-holes. . The rewinding coil mainly includes the first conductive pattern 10 of the first conductive layer, the third conductive pattern 30 of the third conductive layer, the outer peripheral side through hole 71, and the inner peripheral side through hole. It is composed of through holes 81 formed on a concentric circumference having a large diameter.

The first lead wire portion 4 for taking out a signal is connected to the through hole 51 of the first conductive layer, which is the starting point portion of the winding coil shown in FIG. The through hole 51 is connected to the fourth conductive pattern 40 shown in FIG. 5 and is connected to the through hole 61 by the conductive pattern 41 formed in a crank shape of the fourth conductive pattern 40. The through hole 61 is connected to the second conductive pattern 20 shown in FIG. 3, and is connected to the through hole 52 by the conductive pattern 21 formed in a crank shape of the second conductive pattern 20. The through hole 52 is connected to the through hole 62 by the conductive pattern 42 shown in FIG. Thereafter, such a loop goes around the opening 3 clockwise to form a winding coil. The last through hole 6 x of the winding advance coil is connected to the linear conductive pattern 1 x of the first conductive pattern shown in FIG. 2, and the conductive pattern 1 x is connected to the through hole 71.

The through hole 71 is connected to the through hole 81 by the conductive pattern 31 formed in the crank shape of the third conductive pattern 30 shown in FIG. The through hole 81 is connected to the first conductive pattern 10 shown in FIG. 1 and is connected to the through hole 72 by the conductive pattern 11 formed in a crank shape of the first conductive pattern 10. The through hole 72 is connected to the through hole 82 by the conductive pattern 32 shown in FIG. Thereafter, such a loop is made around the opening 3 counterclockwise to form a rewinding coil. The last through hole 8x of the rewinding coil is connected to the linear conductive pattern 2x of the second conductive pattern shown in FIG. 3, and the conductive pattern 2x which is the end point of the rewinding coil is a second lead for extracting a signal. It is connected to the line part 5.

As can be seen by comparing FIG. 2 and FIG. 3, the first lead-out line portion 4 and the second lead-out line portion 5 are formed in the first conductive layer and the second conductive layer, respectively, through the through hole 6. The conductive pattern of the first conductive layer and the conductive pattern of the second conductive layer are electrically connected. The conductive pattern constituting the first lead wire portion 4 and the conductive pattern constituting the second lead wire portion 5 are partially overlapped so that current flows in opposite directions, and seen through from the stacking direction of the circuit board 2 It is formed in an intersecting pattern that is X-shaped (hereinafter abbreviated as front view).

Radial portions 11a outside the respective crank-shaped conductive patterns 11 of the first conductive pattern 10 shown in FIG. 2 and the respective crank-shaped conductive patterns 31 of the third conductive pattern 30 shown in FIG.
The outer radial portions 31a overlap each other when viewed from the front. Further, the second shown in FIG.
The outer radial portion 21a of each crank-shaped conductive pattern 21 ... of the conductive pattern 20 and the outer radial portion 41a of each crank-shaped conductive pattern 41 ... of the fourth conductive pattern 40 shown in FIG. They overlap each other visually. On the other hand, the radial portions 11a and 31a of the first conductive pattern 10 and the third conductive pattern 30 and the radial portions 21a and 41a of the second conductive pattern 20 and the fourth conductive pattern 40 do not overlap each other when viewed from the front. Adjacent.

Further, a circumferential portion 11b of each crank-shaped conductive pattern 11 of the first conductive pattern 10 shown in FIG. 2 and each crank-shaped conductive pattern 2 of the second conductive pattern 20 shown in FIG.
The circumferential portions 21b of 1... Overlap each other in a front view. Similarly, a circumferential portion 31b of each crank-shaped conductive pattern 31 of the third conductive pattern 30 shown in FIG.
And the circumferential portions 41b of the respective crank-like conductive patterns 41 of the fourth conductive pattern 40 shown in FIG. 5 overlap each other when viewed from the front. Further, the first conductive pattern 1 shown in FIG.
A radial portion 11c inside each crank-shaped conductive pattern 11 of 0 and the third shown in FIG.
The inner radial portions 31c adjacent to the respective crank-shaped conductive patterns 31 of the conductive pattern 30 overlap each other in a front view. Similarly, the radial portion 21c inside each crank-shaped conductive pattern 21 of the second conductive pattern 20 shown in FIG. 3 and each crank-shaped conductive pattern 41 of the fourth conductive pattern 40 shown in FIG. Next to the inner radial portion 41c
Are overlapped with each other when viewed from the front.

Thus, the circuit board 2 has four conductive layers on which conductive patterns are formed, and the conductive patterns forming the winding advance coil and the rewinding coil are seen through from the stacking direction of the circuit board 2, Therefore, compared to the conventional example shown in FIG. 12, the total number of turns of the Rogowski coil 1 can be increased, the voltage of the output signal can be increased, and the S / N can be increased. In addition, since the conductive pattern of the winding advance coil and the conductive pattern of the rewinding coil are formed in different conductive layers, an extra through hole is provided to overcome the conductive pattern of the winding advance coil and the conductive pattern of the rewinding coil. This is not necessary, and the total number of through holes in the circuit board 2 does not increase, and it is possible to prevent a decrease in yield. Furthermore, since the area surrounded by the winding coil and the area surrounded by the rewinding coil are almost equal to the magnetic field parallel to the stacking direction of the circuit board 2, it is offset by the influence from the external magnetic field, and the noise component is more The S / N can be further increased by decreasing the number.

On the other hand, the area surrounded by one turn in the poloidal direction of the toroidal coil is affected by the external magnetic field orthogonal to the stacking direction of the circuit board 2. However, the Rogowski coil 1 is formed on the circuit board 2 in which the conductive layer and the insulating layer are laminated. As described above, the conductive patterns that form the winding coil and the conductive pattern that forms the rewinding coil. Or the conductive pattern forming the winding coil and the conductive pattern forming the rewinding coil overlap so that currents flow in opposite directions. More specifically, FIG.
As shown in FIG. 4, the radial portions 11 of the conductive pattern 11 connected through the through holes 71
a and the radial portion 31a of the conductive pattern 31 overlap each other when viewed from the front, and even when affected by the external magnetic field in the direction of arrow A, the current flowing in the radial portion 11a of the conductive pattern 11 and the radial portion 31a of the conductive pattern 31 The directions of the currents flowing through are reversed and cancel each other. The same applies to the radial portion 21 a of the conductive pattern 21 and the radial portion 41 a of the conductive pattern 41 connected through the through hole 52.

As described above, the winding advance coil and the rewinding coil are connected to each other, and the winding direction of the coil is reversed. Therefore, when affected by the external magnetic field in the direction of arrow B, the circumferential portion 11b of the conductive pattern 11 and the circumferential portion 21b of the conductive pattern 21 overlap each other in front view. The directions of the currents flowing in the circumferential portion 11b and the circumferential portion 21b of the conductive pattern 21 are reversed and cancel each other. The same applies to the circumferential portion 31b of the conductive pattern 31 and the circumferential portion 41b of the conductive patterns 41. Further, the radial portion 11 c inside the conductive pattern 11 and the inner radial portion 31 c next to the conductive pattern 31, and the radial portion 21 c inside the conductive pattern 21 and the inner radial portion 41 c next to the conductive pattern 41 are used. Is the same.

As described above, the winding advance coil and the rewinding coil respectively surround the opening 3 and have two holes C1 and C2 each having a large and small diameter, and every other through hole 61 and 81 at a predetermined interval.
Therefore, it is possible to design a coil with high output and high sensitivity by making the conductive pattern (coil pattern) dense. Further, with respect to an external magnetic field orthogonal to the stacking direction of the circuit board 2, 1
Since the current flowing in the conductive pattern formed in one conductive layer is canceled by the current flowing in the conductive pattern formed in the adjacent conductive layer, the S / N can be reduced by reducing the noise component. It can be even higher. In particular, an external magnetic field generated by a current other than the current to be measured has a greater influence as it is closer to the current, and therefore, it is preferable to cancel the currents flowing in the conductive pattern formed in the closer conductive layer.

Regarding the first lead-out line portion 4 and the second lead-out line portion 5 also, the conductive pattern constituting the first lead-out line portion 4 and the conductive pattern constituting the second lead-out line portion 5 are such that currents flow in opposite directions. , Partially intersecting, and formed in an intersecting pattern that is X-shaped when viewed from the front. Therefore, the current flowing through the first lead line portion 4 and the current flowing through the second lead line portion 5 cancel each other against the influence of the external magnetic field, so the first lead line portion 4 and the second lead line portion 5 It is possible to prevent the S / N from being lowered.

(Second Embodiment)
Next, the Rogowski coil according to the second embodiment of the present invention will be described. The Rogowski coil 1 according to the second embodiment is also formed on the circuit board 2 formed by alternately stacking four conductive layers and three insulating layers, and the case of the first embodiment shown in FIG. Similarly, a circular opening for passing a conductor through which a current to be measured flows is formed in the center of the circuit board 2 (not shown). 7 to 10 show conductive patterns of the first to fourth conductive layers of the circuit board 2 in the second embodiment, respectively. Further, along the circular opening, through-holes 161 on the inner peripheral side are formed at every other interval on the circumference of the two concentric circles C1 and C2. Further, in the outer peripheral portion of the circuit board 2, through holes 151 on the outer peripheral side at predetermined intervals on the circumference of a single circumference C3.
It is the same that is formed. Further, each through hole is formed so as to penetrate through the four conductive layers and the three insulating layers.

In the second embodiment, the winding advance coil electrically converts the winding advance conductive pattern formed in the first conductive layer and the fourth conductive layer forming the circuit board 2 and the winding advance conductive pattern formed in these two conductive layers. A toroidal coil formed by connecting through holes, and the rewinding coil is a planar coil formed on the second conductive layer forming the circuit board 2 and formed so as to substantially go around the opening. . As shown in FIG. 9, the third conductive pattern 130 of the third conductive layer is formed with only the conductive patterns constituting the first lead line portion 4 and the second lead line portion 5 for extracting signals. In addition, the conductive pattern of the other part constituting the first lead line part 4 and the second lead line part 5 is also formed in the fourth conductive pattern 140 of the fourth conductive layer.

As can be seen by comparing FIG. 9 and FIG. 10, the first lead line portion 4 and the second lead line portion 5 are
The third conductive pattern 130 of the third conductive layer and the fourth conductive pattern 140 of the fourth conductive layer are electrically connected through the through hole 6. Similar to the first embodiment, the conductive pattern constituting the first lead wire portion 4 and the conductive pattern constituting the second lead wire portion 5 are partially overlapped so that currents flow in opposite directions, and the front surface It is formed in an intersecting pattern that looks X-shaped.

As shown in FIG. 7, in the first conductive pattern 110, except for the through holes 15 x and 16 x, there is a gap between the outer peripheral through hole 151... And the inner peripheral through hole 161. Crank-shaped conductive pattern 111 having substantially the same shape except for the length of the radial portion of the portion
... are connected. As shown in FIG. 9, the first lead wire portion 4 is connected to the through hole 151 of the third conductive layer, and the through hole 151 is connected to the first conductive pattern 1 shown in FIG.
10 and through hole 1 by conductive pattern 111 of first conductive pattern 110.
61 is connected. The through hole 161 is connected to the fourth conductive pattern 140 shown in FIG. 10, and is connected to the through hole 152 by the conductive pattern 141 formed radially of the fourth conductive pattern 140. The through hole 152 is connected to the through hole 162 by the conductive pattern 112 shown in FIG. Hereinafter, such a loop is rotated around the opening clockwise to form a winding advance coil.

The last through hole 15x of the winding advance coil is connected to the linear conductive pattern 121 in the radial direction of the second conductive pattern 120 shown in FIG. The conductive pattern 121 is connected to an annular conductive pattern 122 that makes a round in the counterclockwise direction so as to surround the inner through-holes 161. The end of the annular conductive pattern 122 is connected to the through hole 16x, and as shown in FIG. 10, the linear conductive pattern 14x of the fourth conductive pattern 140 is formed.
The conductive pattern 14x is connected to the second lead line portion 5 for extracting a signal.

In the second embodiment, in the first conductive pattern 110, in order to reduce the pitch of the conductive patterns 111..., The shape of the crank-shaped portion is not a circumferential direction but a predetermined angle with respect to the circumferential direction. It is formed diagonally so as to form Also in the second embodiment, in order to satisfy the condition that the conductive patterns forming the winding advance coil and the rewinding coil overlap each other as seen through from the direction parallel to the stacking direction of the circuit board, the second conductive pattern 12
A zero-shaped conductive pattern 122 is formed in a sawtooth shape. Thereby, the same effect as in the case of the first embodiment can be obtained.

According to the configuration of the second embodiment, the toroidal coil has the first conductive pattern 11 of the first conductive layer.
0 and the fourth conductive pattern 140 of the fourth conductive layer, and through holes 151..., 161. Therefore, the cross-sectional area in the poloidal direction of the toroidal coil for detecting the original current to be measured is increased, and the output voltage can be increased.

In addition, this invention is not limited to description of the said embodiment, A various deformation | transformation is possible. For example, among the three insulating layers, the thickness of the central insulating layer may be larger than the thickness of the other two insulating layers. Thereby, the cross-sectional area of the toroidal coil in the poloidal direction can be increased, the output voltage can be further increased, and the S / N can be further improved. It is also possible to form a plurality of Rogowski coils on a single circuit board using a built-up board. Thereby, the output voltage can be further increased, and the S / N can be further improved.

DESCRIPTION OF SYMBOLS 1 Rogowski coil 2 Circuit board 3 Opening 4 1st lead-out line part 5 2nd lead-out line part 6 Through hole 10 1st conductive pattern (of 1st Embodiment) 11, 21, 31, 41, 1x, 2x, 3x Conductivity Patterns 11a, 21a, 31a, 41a Radial portions 11b, 21b, 31b, 41b (conductive patterns) Radial portions 11c, 21c, 31c, 41c Radial portions 20 (first conductive patterns) Second conductive pattern 30 (of the first embodiment) Third conductive pattern 40 (of the first embodiment) Fourth conductive pattern (of the first embodiment) 51, 52, 53, 61, 62, 71, 81, 82, 6x, 8x Through hole 110 First conductive pattern 120 (of the second embodiment) Second conductive pattern 130 (of the second embodiment) 130th (of the second embodiment) Conductive patterns 140 (the second embodiment) The fourth conductive patterns 111, 112, 121, 122 conductive pattern 151,152,161,162,15x, 16x through hole

Claims (9)

A current in which a toroidal coil is formed on a circuit board formed by laminating a plurality of conductive layers and a plurality of insulating layers in a central portion so as to penetrate a conductor through which a current to be measured flows. A measuring coil,
A winding coil and a winding coil whose winding directions are opposite to each other with respect to a magnetic field parallel to the stacking direction of the circuit board;
Each of the winding advance coil and the rewinding coil surrounds the opening, and on the two circumferences having large and small diameters, every other through hole is formed at predetermined intervals.
The current measuring coil, wherein the conductive patterns formed on the plurality of conductive layers and forming the winding advance coil and the rewinding coil overlap each other as seen through from the stacking direction of the circuit board. Conductive patterns that form the winding advance coil, conductive patterns that form the rewinding coil, or conductive patterns that form the winding advance coil and the rewinding with respect to a magnetic field orthogonal to the stacking direction of the circuit board. The current measuring coil according to claim 1, wherein the conductive patterns forming the coil overlap so that currents flow in opposite directions. The winding advance coil is formed by a winding advance conductive pattern formed in two conductive layers forming the circuit board and a through hole that electrically connects the winding advance conductive pattern formed in the two conductive layers. A toroidal coil,
The rewinding coil is a through hole that electrically connects a rewinding conductive pattern formed on the other two conductive layers forming the circuit board and a rewinding conductive pattern formed on the other two conductive layers. The current measuring coil according to claim 1, wherein the current measuring coil is a toroidal coil formed by: The winding advance coil is formed by a winding advance conductive pattern formed in two conductive layers forming the circuit board and a through hole that electrically connects the winding advance conductive pattern formed in the two conductive layers. A toroidal coil,
The rewinding coil is a planar coil formed in another conductive layer forming the circuit board and formed so as to substantially go around the opening. The coil for current measurement according to 2. Two concentric circles having a plurality of through-holes formed in the stacking direction of the circuit board and electrically connecting the conductive patterns formed in the plurality of conductive layers have different diameters on the inner peripheral side close to the opening. 5. Every other circumference is formed at a predetermined interval, and is formed at a predetermined interval on a single circumference on the outer peripheral side far from the opening. The coil for current measurement according to item. The circuit board is formed by stacking four conductive layers and three insulating layers, and all the through holes are formed to penetrate the four conductive layers and the three insulating layers. The current measuring coil according to claim 5. 7. The current measuring coil according to claim 1, wherein, of the three insulating layers, the thickness of the central insulating layer is thicker than the thicknesses of the other two insulating layers. . The first lead wire portion connected to the start point portion of the winding advance coil and the second lead wire portion connected to the end point portion of the rewind coil are formed in a pattern in which currents flow in opposite directions. The current measurement coil according to claim 1, wherein the current measurement coil is a current measurement coil. 9. The current measuring coil according to claim 8, wherein the first lead line portion and the second lead line portion are formed in different conductive layers of the circuit board, respectively.

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