Coreless current sensor

Abstract

To provide a coreless current sensor capable of having high detection sensitivity even when small-sized.SOLUTION: A coreless current sensor comprises a pair of pattern coils 11, 12 and a pair of pattern coils 13, 14, wherein the pattern coils 11 to 14 are so connected that induction currents due to magnetically detected induced electromotive force are summed up, and the pattern coils 12, 13 are so arranged between the center axis C3 of a current bar 3 and the center axis C4 of a current bar 4 as to cross a vertical plane PL1 at the same distance from the current bar 3 and current bar 4, and also arranged on the same plane PL2 passing the current bar 3 including a top surface 3a or a reverse surface 3b or the current bar 4 including a top surface 4a or a reverse surface 4b.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a coreless current sensor that can obtain high detection sensitivity even with a small size.

Background Art

[0002] Conventional current sensors have a U-shaped magnetic flux concentrating core that sandwiches a current bar, and a detection substrate with a magnetic detection coil interposed in the gap of this magnetic flux concentrating core is arranged. The structure of this current sensor is disclosed in, for example, Patent Document 1.

[0003] By using a magnetic flux concentrating core, this current sensor converges the magnetic flux generated from the current bar, so that a large amount of magnetic flux can be linked to the magnetic detection coil, the induced electromotive force can be increased, and high detection sensitivity can be ensured. Further, since this current sensor uses a magnetic flux concentrating core, the external magnetic field is absorbed by the magnetic flux concentrating core, so that the external magnetic field linked to the magnetic detection coil is reduced, and the influence of the external magnetic field can be reduced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, since conventional current sensors use a magnetic flux concentrating core, they have problems of large three-dimensional size and high cost.

[0006] The present invention has been made in view of the above, and an object thereof is to provide a coreless current sensor that can obtain high detection sensitivity even with a small size.

Means for Solving the Problems

[0007] In order to solve the above-described problems and achieve the object, the present invention includes a folded conductor bar in which a first current bar and a second current bar are arranged in parallel, and one end of the first current bar and one end of the second current bar are folded and connected. A coreless current sensor that detects the magnetism generated by the currents flowing through the first current bar and the second current bar and measures the current, and includes a pair of first pattern coils that magnetically detect the circumferential magnetic flux generated by at least the first current bar as the interlinking magnetic flux, and at least the second current bar. And a pair of second pattern coils that magnetically detect the circumferential magnetic flux generated as the interlinking magnetic flux, and each first pattern coil and each second pattern coil are connected so that induced currents caused by the induced electromotive force for magnetic detection are added. One of the pair of first pattern coils and one of the pair of second pattern coils are arranged between the central axis of the first current bar and the central axis of the second current bar so as to intersect a vertical plane in which the distances from the first current bar and the second current bar are equal, and It is arranged on the same plane passing through the first current bar including the upper surface or the lower surface and the second current bar including the upper surface or the lower surface.

[0008] Further, in the present invention, in the above invention, one winding center of the pair of first pattern coils and one winding center of the pair of second pattern coils arranged between the first current bar and the second current bar pass through the vertical plane. It is characterized by that.

[0009] Further, in the present invention, in the above invention, one of the pair of first pattern coils and one of the pair of second pattern coils arranged between the first current bar and the second current bar are arranged so as to overlap on the same plane. It is characterized by that.

[0010] Further, in the present invention, in the above invention, the pair of first pattern coils are arranged opposite to the first current bar and have opposite winding directions, the pair of second pattern coils are arranged opposite to the second current bar and have opposite winding directions, and the winding directions of the first pattern coil and the second pattern coil arranged between the first current bar and the second current bar are the same.

[0011] Further, in the present invention, in the above invention, a sensor substrate is fixedly arranged on the upper surface or the lower surface of the first current bar and the second current bar and provided on the same plane, and the pair of first pattern coils and the pair of second pattern coils are arranged on the sensor substrate.

[0012] Further, in the present invention, in the above invention, each of the first pattern coils and each of the second pattern coils is a pattern coil having a multilayer structure formed in the sensor substrate.

[0013] Further, in the present invention, in the above invention, the first current bar and / or the second current bar is bent, the distance between the first current bar and the second current bar is the same distance or different distances through the bent portion, and the pair of first pattern coils and the pair of second pattern coils are arranged longitudinally before and after the bent portion.

Advantages of the Invention

[0014] According to the present invention, high detection sensitivity can be obtained even with a small size.

Brief Description of the Drawings

[0015]

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Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

[0017] <Schematic Configuration> FIG. 1 is a schematic diagram showing the general configuration of a coreless current sensor 1 according to an embodiment of the present invention. Note that FIG. 1(a) is a schematic plan view of the coreless current sensor 1, and FIG. 1(b) is a schematic front view of the coreless current sensor 1. This coreless current sensor 1 uses planar pattern coils 11 to 14 wound in a spiral shape without using a magnetic core.

[0018] As shown in FIG. 1, the coreless current sensor 1 has a lead-in current line 2 drawn from a current line through which a current flows. The lead-in current line 2 has two current bars 3 and 4 arranged in parallel at a distance d, and a folded conductor bar 5 at one end of the current bars 3 and 4 where the lead-in current line 2 is folded back.

[0019] On the side of the current bar 3 which is the first current bar and on the side of the folded conductor bar 5, a pair of first pattern coils, i.e., pattern coils 11 and 12, are arranged opposite to the current bar 3. Also, on the side of the current bar 4 which is the second current bar and on the side of the original current line, a pair of second pattern coils, i.e., pattern coils 13 and 14, are arranged opposite to the current bar 4. The pattern coils 11 and 12 magnetically detect at least the circumferential magnetic flux φ1 generated by the current bar 3 as the linked magnetic flux. The pattern coils 13 and 14 magnetically detect at least the circumferential magnetic flux φ2 generated by the current bar 4 as the linked magnetic flux.

[0020] The pattern coils 11 to 14 are provided on a sensor substrate 7, and the sensor substrate 7 is in contact with the upper surfaces 3a of the current bar 3 and 4a of the current bar 4 and is fixedly arranged on the current bars 3 and 4. Therefore, the pattern coils 11 to 14 are arranged on the same plane PL2 of the sensor substrate 7.

[0021] The pattern coils 12 and 13 are arranged between the central axis C3 of the current bar 3 and the central axis C4 of the current bar 4 so as to intersect a vertical plane PL1 at an equal distance from the current bars 3 and 4, and are arranged on the same plane PL2 passing through the current bar 3 including the upper surface 3a or the lower surface 3b of the current bar 3 and the current bar 4 including the upper surface 4a or the lower surface 4b of the current bar 4.

[0022] Also, the winding centers PC2 and PC3 of the pattern coils 12 and 13 are formed on the vertical plane PL1, and the winding directions of the pattern coils 12 and 13 are the same. Note that the winding direction of the pattern coil 11 is opposite to that of the pattern coil 12, and the winding direction of the pattern coil 14 is opposite to that of the pattern coil 13.

[0023] The pattern coils 11 to 14 are connected such that the induced currents caused by the induced electromotive forces magnetically detected by the respective pattern coils 11 to 14 are added. Specifically, as shown in FIG. 1, when a current I flows from the current bar 3 side to the current bar 4 side, a clockwise current I1 flows through the pattern coil 11 as shown by the arrow in the figure, a counterclockwise current I2 flows through the pattern coil 12 as shown by the arrow in the figure, a counterclockwise current I3 flows through the pattern coil 13 as shown by the arrow in the figure, a clockwise current I4 flows through the pattern coil 14 as shown by the arrow in the figure, and a current IS obtained by adding the respective currents I1 to I4 is output to the current arithmetic unit 100 side.

[0024] Here, the current arithmetic unit 100 calculates the current I based on the relationship between the detected current IS and the current I flowing through the current bars 3 and 4. The current arithmetic unit 100 also has functions such as signal amplification processing and noise removal processing.

[0025] <Influence of External Magnetic Field> FIG. 2 is an explanatory diagram for explaining the influence of an external magnetic field due to the arrangement and winding direction of the pattern coils 11 to 14 shown in FIG. 1. FIG. 2 shows the state of induced currents flowing through the respective pattern coils 11 to 14 when there is an external magnetic field having a magnetic flux in the -Z direction. As shown in FIG. 2, when there is an external magnetic field having an external magnetic flux φ11 in the -Z direction, in the pattern coil 11, an induced current IE1 wound counterclockwise in the figure flows, and in the pattern coil 12, an induced current IE2 wound counterclockwise in the figure flows. However, since the winding directions of the pattern coils 11 and 12 are different, the induced current IE1 and the induced current IE2 cancel each other out. Similarly, in the pattern coil 13, an induced current IE3 wound counterclockwise in the figure flows, and in the pattern coil 14, an induced current IE4 wound counterclockwise in the figure flows. However, since the winding directions of the pattern coils 13 and 14 are different, the induced current IE3 and the induced current IE4 cancel each other out. As a result, the detection current obtained by the pattern coils 11 to 14 is less likely to be affected by the external magnetic field.

[0026] In addition, in order to provide such a function of removing the influence of the external magnetic field, it is necessary to make the magnetic detection capabilities of the pattern coils 11 and 12 the same and make the magnetic detection capabilities of the pattern coils 13 and 14 the same. That is, it is necessary to make the shapes including the number of turns of the pattern coils 11 and 12 the same, and it is necessary to make the shapes including the number of turns of the pattern coils 13 and 14 the same.

[0027] <Improvement of Detection Sensitivity> FIG. 3 is a diagram showing an example in which the shapes of the pattern coils 11 to 14 shown in FIG. 1 are rectangles elongated in the longitudinal direction (±Y direction) of the current bars 3 and 4. As shown in FIG. 3, for the pattern coils 11 to 14, the width Y1 in the Y direction is made larger than the width X1 in the X direction of the pattern coils 11 to 14 so that the aspect ratio of the major and minor diameters of the pattern coils 11 to 14 exceeds 1. Since the width X1 in the X direction of the pattern coils 13 and 14 is limited by the current bars 3 and 4, by increasing the width of the width Y1 in the Y direction, more magnetic flux linked can be obtained, and the detection sensitivity can be improved.

[0028] In addition, in the present embodiment, since the pattern coil 12 has not only the circumferential magnetic flux φ1 of the current bar 3 but also the circumferential magnetic flux φ2 of the current bar 4 as the linked magnetic flux, the induced electromotive force increases and the detection sensitivity improves. Similarly, since the pattern coil 13 has not only the circumferential magnetic flux φ2 of the current bar 4 but also the circumferential magnetic flux φ1 of the current bar 3 as the linked magnetic flux, the induced electromotive force increases and the detection sensitivity improves.

[0029] FIG. 4 is an explanatory diagram for explaining the magnetic fluxes received by the pattern coils 11 to 14 from the current bars 3 and 4. FIG. 5 is an explanatory diagram for explaining the magnetic fluxes received by the conventional pattern coils 111 to 114 from the current bars 103 and 104. The pattern coils 111 to 114 are arranged in a row in the X direction. Note that the current bars 103 and 104 correspond to the current bars 3 and 4. Also, the pattern coils 11 to 14 and 111 to 114 have the same shape.

[0030] Here, consider the magnetic fluxes received by the pattern coils 11 to 14 from the current bars 3 and 4. The magnetic flux generated at the position where the distance between the current bars 3 and 4 and the central axes C11 to C14 of the pattern coils 11 to 14 in the X direction is (X1 + X2) / 2 is calculated as "1". Since the circumferential magnetic fluxes φ1 and φ2 generated by the current bars 3 and 4 are semi-proportional to the distances from the central axes C3 and C4 of the current bars 3 and 4, for example, when the distance is doubled, the magnetic flux becomes 1 / 2.

[0031] In the coreless current sensor of the present embodiment shown in FIG. 4, the magnetic fluxes received by the respective pattern coils 11 to 14 from the current bars 3 and 4 are Pattern coil 11: 1 - (1 / 3) = 2 / 3 Pattern coil 12: 1 + 1 = 2 Pattern coil 13: 1 + 1 = 2 Pattern coil 14: -(1 / 3) + 1 = 2 / 3 and the total magnetic flux is (2 / 3) + 2 + 2 + (2 / 3) = 16 / 3 = 80 / 15 as follows.

[0032] On the other hand, the magnetic fluxes received by the pattern coils 111 to 114 in the conventional coreless current sensor shown in FIG. 5 from the current bars 103 and 104 are as follows: Pattern coil 111: 1 - (1 / 5) = 4 / 5 Pattern coil 112: 1 + 1 / 3 = 4 / 3 Pattern coil 113: 1 / 3 + 1 = 4 / 3 Pattern coil 114: -(1 / 5) + 1 = 4 / 5 Therefore, the total magnetic flux is (4 / 5) + (4 / 3) + (4 / 3) + (4 / 5) = 64 / 15 That is.

[0033] Therefore, the coreless current sensor according to the present embodiment has a detection sensitivity improved by (80 / 15) / (64 / 15) = 1.25 times compared to the conventional coreless current sensor.

[0034] <Modification Example 1> FIG. 6 is a schematic diagram showing a schematic configuration of Modification Example 1 of the coreless current sensor according to the present embodiment. Note that FIG. 6(a) is a schematic plan view of the coreless current sensor of Modification Example 1, and FIG. 6(b) is a cross-sectional view taken along line A-A of FIG. 6(a). In the above embodiment, the pair of pattern coils 11 and 12 and the pair of pattern coils 13 and 14 are arranged stepwise in the Y direction. However, in this Modification Example 1, the Y-direction positions of the pair of pattern coils 13 and 14 are made to coincide with the Y-direction positions of the pair of pattern coils 11 and 12, and the pattern coils 12 and 13 are arranged overlapping each other. As a result, the winding centers PC2 and PC3 of the pattern coils 12 and 13 coincide. The pattern coils 12 and 13 become one pattern coil 15 arranged in multiple layers.

[0035] In Modification Example 1, the size in the Y direction becomes shorter, and a more compact-sized coreless current sensor can be realized. Further, although the pattern coils 12 and 13 have a multilayer structure, the connection lines between the pattern coils 12 and 13 become shorter, and the influence by noise can be reduced.

[0036] <Modification Example 2> In the above-described embodiment, the pattern coils 11 to 14 were described as single-layer coils. However, in this Modification 2, each of the pattern coils 11 to 14 has a multilayer structure. Thereby, the detection sensitivity can be further enhanced.

[0037] FIG. 7 is a cross-sectional view showing the multilayer structure of the pattern coil. As shown in FIG. 7, the sensor substrate 7 has a four-layer structure including a first-layer coil layer L1, a second-layer coil layer L2, a third-layer coil layer L3, and a fourth-layer coil layer L4.

[0038] In this Modification 2, as shown in FIG. 8, bent portions 16 and 17 are provided in the middle of the longitudinal direction of the current bars 3 and 4, either on both or one of them. In FIG. 8(a), both of the current bars 3 and 4 have bent portions 16 and 17 that bend in one direction (+X direction) at the same Y-direction position. The distances between the current bars 3c and 3d and between the current bars 4c and 4d before and after the longitudinal direction of the bent portions 16 and 17 are the same. Thereby, while enhancing the detection sensitivity, the size in the X direction can be further reduced.

[0039] On the other hand, in FIG. 8(b), the bent portion 17 is provided only on the current bar 4. In this case, the distances between the current bars 3 and 4c and between the current bars 3 and 4d before and after the longitudinal direction of the bent portions 16 and 17 are different, and the distance between the current bars 3 and 4d becomes wider. Also in this case, while enhancing the detection sensitivity of the pair of pattern coils 11 and 12, the size in the X direction can be reduced. When widening the distance between the current bars 3 and 4d, for example, it is a case where it is desired to enhance the mountability of the lead-in current line 2 composed of the current bars 3 and 4 and the folded conductor bar 5.

[0040] <Details of the Multilayer Structure> Next, with reference to FIG. 9, the details of the multilayer structure of the coreless current sensor with respect to the configuration of the current bars 3 and 4 in FIG. 8(a) will be described. FIG. 9 is an explanatory diagram for explaining the details of the multilayer structure of the pattern coils 11 to 14 according to Modification 2. FIG. 9 shows the patterns from the coil layer L1 to the coil layer L4 in the sensor substrate 7. Note that the detailed winding states of the pattern coils in each coil layer are omitted.

[0041] As shown in FIG. 9, first, the pattern coil 11 is connected from the connection terminal T1 to the pattern coil 11 in the coil layer L1 via the connection line LA1, and then is sequentially connected to the pattern coils 11 in the lower layers via the vias V11, V13, and V12. The pattern coil 11 in the lowermost layer (coil layer L4) is connected to the pattern coil 12 in the coil layer L4 via the connection line LA2.

[0042] The pattern coil 12 in the coil layer L4 is then sequentially connected to the pattern coils 12 in the upper layers via the vias V21, V23, and V22. The pattern coil 12 in the uppermost layer (coil layer L1) is connected to the pattern coil 14 in the coil layer L1 via the connection line LA3 and is also connected to the ground connection terminal G.

[0043] The pattern coil 14 in the coil layer L1 is then sequentially connected to the pattern coils 14 in the lower layers via the vias V42, V43, and V41. The pattern coil 14 in the lowermost layer (coil layer L4) is connected to the pattern coil 13 in the coil layer L4 via the connection line LA4.

[0044] The pattern coil 13 in the coil layer L4 is then sequentially connected to the pattern coils 13 in the upper layers via the vias V32, V33, and V31. The pattern coil 13 in the uppermost layer (coil layer L1) is connected to the connection terminal T2 via the connection line LA5.

[0045] Thereby, the connection lines between the four-layer pattern coils 11 to 14 can be shortened, and the intrusion of noise can be prevented. The connection line LA3 is connected to the ground connection terminal G in order to use the ground connection terminal G as a reference potential at the midpoint and perform differential operation on the induced currents of the pattern coils 11 and 12 and the induced currents of the pattern coils 13 and 14 for noise removal.

[0046] <Application to a Wattmeter> For three-phase three-wire or single-phase three-wire watt-hour meters, two current sensors are used. When these two current sensors are current sensors using a magnetic flux concentrating core, the space for arranging the magnetic flux concentrating core is large, the method of drawing in the current bar becomes complicated, and furthermore, insulation measures are required. Here, by using one of the two current sensors as the above-mentioned coreless current sensor, the method of drawing in the current bar for the current sensor using one magnetic flux concentrating core becomes simple, and the overall size can be reduced.

[0047] FIG. 10 is a diagram showing an example in the case of using a current sensor 37 using a magnetic flux concentrating core and a sensor substrate 7 of a coreless current sensor as two current sensors used for a watt-hour meter. FIG. 10(a) shows a state before attaching the current sensor 37 and the sensor substrate 7 of the coreless current sensor, and FIG. 10(b) shows a state after attaching the current sensor 37 and the sensor substrate 7 of the coreless current sensor. Note that the current bars of the terminals 3S and 3L each have bent portions 16 and 17, and the sensor substrate 7 of the coreless current sensor shown in FIG. 9 is arranged between the current bar of the terminal 3S and the current bar of the terminal 3L.

[0048] Thereby, since the current detection of the current flowing through the terminals 3S and 3L is performed by the sensor substrate 7 of the coreless current sensor, the space for the current sensor using one magnetic flux concentrating core becomes available. In addition, the current bar 31 of the current sensor 37 in which the detection substrate 33 is attached to the magnetic flux concentrating core 32 only passes through the magnetic flux concentrating core 32 and linearly connects the terminals 1S and 1L, and the configuration of the current bar 31 becomes simple, and the insulation countermeasure components are reduced. Note that the relay 40 connects and disconnects the current bar.

[0049] On the other hand, FIG. 11 is a diagram showing an example in the case of using two coreless current sensors as two current sensors used for a watt-hour meter. FIG. 11(a) shows a state before attaching the sensor substrates 7 of the two coreless current sensors, and FIG. 11(b) shows a state after attaching the sensor substrates 7 of the two coreless current sensors.

[0050] As a result, the current detection of the current flowing through the terminals 3S and 3L and the current detection of the current flowing through the terminals 1S and 1L are both performed by the sensor substrate 7 of the coreless current sensor. Therefore, a large space for the current sensor using two magnetic cores is vacated, and the overall configuration size is significantly reduced. As shown in Fig. 11(b), the two sensor substrates 7 are fixed by a plurality of screws 7a with the terminals 3S and 3L and the terminals 1S and 1L as current bars, respectively. The screw 7a is fixed through the screw hole 21 shown in Fig. 9 and the screw hole 35 formed in the current bar corresponding to the position of the screw hole 21. An insulating sheet such as polycarbonate is attached to the current bar side of the sensor substrate 7. The fixing by the screw 7a is the same for the sensor substrate 7 in Fig. 10.

[0051] Note that the coreless current sensor and the current sensor using a magnetic core include the configuration of the current bar to be detected.

[0052] In the above embodiments and modifications, since the pattern coils 11 to 14 are formed on the sensor substrate 7, although the pattern coils 11 to 14 do not exist between the current bars 3 and 4, it can be said that they substantially exist between the current bars 3 and 4. In particular, in the case of a strip-shaped current bar, it can be said that the pattern coils 11 to 14 are substantially the same as those existing between the current bars 3 and 4. As shown in Fig. 12, sensor substrates 8a to 8d having the pattern coils 11 to 14 may be provided below the substrate 8 so that the pattern coils 11 to 14 are accommodated within the width W of the current bars 3 and 4. Of course, instead of the sensor substrates 8a to 8d, the pattern coils 11 to 14 may be formed on the lower surface of the substrate 8.

[0053] Note that the pattern coils 11 and 12 and the pattern coils 13 and 14 may be provided on separate sensor substrates, respectively. Also, the pattern coils 11 and 14 do not necessarily need to be arranged opposite to the pattern coils 12 and 13, respectively. That is, the pattern coils 12 and 13 need to be arranged on the same plane PL2, but the pattern coils 11 and 14 do not necessarily need to be arranged on the same plane PL2.

[0054] Also, as shown in Modification 2, the X-direction positions of the winding centers PC2 and PC3 of the pattern coils 12 and 13 do not have to match.

[0055] Note that each configuration illustrated in the above embodiments and modifications is schematic in function, and does not necessarily have to be physically configured as shown in the drawings. That is, the form of distribution and integration of each device and component is not limited to that shown in the drawings, and all or part of them can be functionally or physically distributed and integrated in any unit according to various usage situations and the like.

Explanation of Reference Numerals

[0056] 1 Coreless current sensor 2 Incoming current line 3, 3c, 3d, 4, 4c, 4d, 31, 103, 104 Current bar 3a, 4a Upper surface 3b, 4b Lower surface 5 Conductor bar 7, 8a~8d Sensor substrate 7a Screw 8 Substrate 11~15, 111~114 Pattern coil 16, 17 Bending portion 21, 35 Screw hole 32 Magnetic flux concentrating core 33 Detection substrate 37 Current sensor 40 Relay 100 Current calculation unit C3, C4, C11~C14 Central axis G Ground connection terminal I, I1~I4, IE1~IE4, IS Current L1~L4 Coil layer LA1~LA5 Connection line PC2, PC3 Winding center PL1 Vertical plane PL2 Same plane T1, T2 Connection terminal V11~V13, V21~V23, V31~V33, V41~V43 Via X1, Y1, W width φ1, φ2 circumferential magnetic flux φ11 external magnetic flux

Claims

1. A coreless current sensor comprising a folded conductor bar in which a first current bar and a second current bar are arranged in parallel, and one end of the first current bar and one end of the second current bar are folded and connected, and detecting magnetism generated by currents flowing through the first current bar and the second current bar to measure the current, a pair of first pattern coils that magnetically detect the circumferential magnetic flux generated by at least the first current bar as the interlinked magnetic flux, a pair of second pattern coils that magnetically detect the circumferential magnetic flux generated by at least the second current bar as the interlinked magnetic flux, comprising: each first pattern coil and each second pattern coil are connected so that induced currents caused by the induced electromotive force for magnetic detection are added, one of the pair of first pattern coils and one of the pair of second pattern coils are arranged between the central axis of the first current bar and the central axis of the second current bar so as to intersect a vertical plane in which the distances from the first current bar and the second current bar are equal, and are arranged on the same plane passing through the first current bar including the upper or lower surface and the second current bar including the upper or lower surface. The coreless current sensor is characterized by this.

2. The coreless current sensor according to claim 1, wherein the winding center of one of the pair of first pattern coils and the winding center of one of the pair of second pattern coils arranged between the first current bar and the second current bar pass through the vertical plane.

3. The coreless current sensor according to claim 1, wherein one of the pair of first pattern coils and one of the pair of second pattern coils arranged between the first current bar and the second current bar are arranged overlappingly on the same plane.

4. The pair of first pattern coils are arranged opposite to the first current bar and have opposite winding directions, the pair of second pattern coils are arranged opposite to the second current bar and have opposite winding directions, The coreless current sensor according to claim 1, wherein the winding directions of the first pattern coil and the second pattern coil arranged between the first current bar and the second current bar are the same direction.

5. A sensor substrate is fixedly arranged on the upper or lower surface of the first current bar and the second current bar and provided on the same plane, The coreless current sensor according to claim 1, wherein the pair of first pattern coils and the pair of second pattern coils are arranged on the sensor substrate.

6. The coreless current sensor according to claim 4, wherein each of the first pattern coils and each of the second pattern coils is a pattern coil having a multilayer structure formed within the sensor substrate.

7. The first current bar and / or the second current bar is bent, and the distance between the first current bar and the second current bar is the same distance or different distances via the bent portion, The coreless current sensor according to claim 1, wherein the pair of first pattern coils and the pair of second pattern coils are arranged longitudinally before and after the bent portion.

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