JP2013160638A - Current detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a current flowing a target object without inserting the object through a coil.SOLUTION: A current detector 10 includes an annular current detecting coil 14 and a current line part 12 penetrating through the coil 14. The current line part 12 has mounting parts 12a, 12b disposed at both ends and connected to the object 100.

Description

  The present invention relates to a current detector having an annular current detection coil.

  Conventionally, a current detector having a coil formed in an annular shape, for example, a laminated Rogowski coil, is known. However, in this conventional configuration, it is necessary to pass a linear conductor, which is an object of current detection, inside the coil, and a circuit board on which the conductor is mounted is processed in order to pass the conductor inside the coil. There is a need to.

JP 2009-85620 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a current detector that can detect the current flowing through the current detection target without passing the current detection target through the inside of the coil. It is to provide.

  According to the present invention, the current line portion having the mounting portions connected to the current detection target object at both ends is passed through the annular current detection coil. According to this configuration, by connecting the current detection object to the mounting part, the current flowing through the current detection object can be passed through the current line part and detected by the coil. Thereby, the current flowing through the current detection object can be detected without passing the current detection object inside the coil.

The perspective view which shows 1st Embodiment of this invention and shows the external appearance of a current detector Longitudinal sectional view showing the internal configuration of the current detector The perspective view which shows the structure of a coil The figure which shows the relationship between the frequency of the electric current which flows through an electric current detection target object, and the passage characteristic of the magnetic field generated from an electric current detection target object FIG. 2 equivalent diagram according to the second embodiment FIG. 2 equivalent diagram according to the third embodiment. FIG. 2 equivalent diagram according to the fourth embodiment FIG. 2 equivalent diagram according to the fifth embodiment

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the current detector 10 has a configuration in which a current line portion 12 made of a linear conductor is built in a substrate portion 11 having a substantially rectangular plate shape as a whole. The current line portion 12 has mounting portions 12 a and 12 b at both end portions protruding outward from the side portion of the substrate portion 11. A land portion 13 made of, for example, copper foil is provided at a portion of the substrate portion 11 where the mounting portions 12a and 12b protrude.

Next, the internal configuration of the current detector 10 will be described with reference to FIGS. As shown in FIG. 2, the current detector 10 includes a current detection coil 14 and a magnetic shielding shield 15 in addition to the above-described current line portion 12 inside the substrate portion 11.
The substrate unit 11 has a configuration in which a plurality of, in this case, 12 insulating substrates 11 </ b> A to 11 </ b> L are stacked in the thickness direction of the current detector 10. That is, the substrate unit 11 is a laminated substrate in which a plurality of insulating substrates 11A to 11L are laminated.
The coil 14 is provided on the substrate portion 11 which is a laminated substrate, and as shown in FIG. 3, the coil 14 includes a plurality of coil forming pieces 14a, a plurality of through-hole pins 14b, and a return wire portion 14c. ing.

  The coil forming pieces 14a are each formed in an elongated plate shape. These coil forming pieces 14a are formed in any two layers among the plurality of insulating substrates 11A to 11L constituting the substrate portion 11, and in this case, outside the insulating substrate 11E constituting the intermediate layer. And the outer surface of the insulating substrate 11H. In this case, the outer surface of the insulating substrate 11E is the upper surface in FIG. 2, and the outer surface of the insulating substrate 11H is the lower surface in FIG. The plurality of coil forming pieces 14a are arranged in an annular shape and are arranged in a state of being oriented radially. The through-hole pins 14b are respectively inserted into a plurality of through-holes formed in the insulating substrates 11E to 11H constituting two arbitrary layers of the substrate portion 11, in this case, the intermediate four layers, and are arranged as described above. The plurality of coil forming pieces 14a are electrically connected. The coil forming piece 14 a and the through-hole pin 14 b configured as described above form a winding portion 14 d that is spirally wound in the circumferential direction of the current detector 10.

The return line portion 14c is formed in an elongated plate shape, one end portion thereof is electrically connected to one end portion of the winding portion 14d via the through-hole pin 14b, and the other end portion is configured as described above. The winding portion 14d extends in an annular shape in the circumferential direction. In this case, the return line portion 14c includes the inner surface of the insulating substrate 11F constituting the middle two layers of the plurality of insulating substrates 11A to 11L constituting the substrate portion 11 and the inner surface of the insulating substrate 11G. It is arranged between. In this case, the inner surface of the insulating substrate 11F is the lower surface in FIG. 2, and the inner surface of the insulating substrate 11G is the upper surface in FIG. The other end of the winding portion 14d and the other end of the return wire portion 14c are electrically connected to an external signal processing circuit (not shown). This signal processing circuit performs signal processing of the current detected by the coil 14 and specifies the current flowing through the current detection target 100 made of a conductor.
As described above, the substrate has a winding portion 14d spirally wound in the circumferential direction of the current detector 10 and a return line portion 14c extending in the circumferential direction in the winding portion 14d, and is a laminated substrate. The coil 14 provided in the part 11 is configured as a so-called laminated Rogowski coil.

  Inside the coil 14 configured in this manner, the substantially central portion of the current line portion 12 penetrates along the axial direction of the coil 14. Then, both end portions of the current line portion 12 extend from the portion penetrating the inside of the coil 14 to the upper and lower portions of the coil 14 in the radial direction of the coil 14, and project both end portions thereof to the outside of the substrate portion 11. Yes. And the current line part 12 makes the part protruded from the board | substrate part 11 the mounting parts 12a and 12b. A current detection object 100 made of, for example, a linear conductor is connected to the mounting portions 12a and 12b, for example, by soldering. As a result, the current flowing through the current detection object 100 flows through the current line portion 12. The current detection target 100 may be a board pattern mounted on a circuit board (not shown).

  The shield part 15 is made of a nonmagnetic material and covers the coil 14 configured as described above inside the substrate part 11. This shield portion 15 is provided between the current line portion 12 and the coil 14, and thereby, mainly, an external magnetic field and an external electric field, that is, elements other than the current line portion 12 to which the current detection target 100 is connected. Responsible for shielding the magnetic and electric fields generated from the. And this shield part 15 has the slit 15a in the part which covers the inner peripheral part of the coil 14. FIG. The slit 15 a extends in an annular shape along the circumferential direction of the coil 14, and opens between the coil 14 and the current line portion 12. That is, the shield portion 15 is configured to cover almost the entire coil 14 except for the inner peripheral portion of the coil 14, that is, a part of the portion facing the current line portion 12.

  The slit 15a is formed in the thickness direction of the current detector 10 within a range where the coil 14 exists, in other words, within a range where the insulating substrates 11E to 11H sandwiched between the coils 14 exist. Further, the slit 15a has an opening width in the thickness direction of the current detector 10 that is equal to or less than the thickness of the coil 14, in other words, equal to or less than the sum of the thicknesses of the insulating substrates 11E to 11H sandwiched between the coils 14. ing.

  According to the current detector 10 according to the present embodiment described above, the current flowing through the current detection object 100 penetrates the inside of the coil 14 by connecting the current detection object 100 to the mounting portions 12a and 12b. The current line section 12 flows. The magnetic field generated from the current line portion 12 acts on the coil 14 through the slit 15a of the shield portion 15 without being shielded. That is, the current flowing through the current detection object 100 can be passed through the current line portion 12 and detected by the coil 14, so that the current detection object 100 can be detected without passing the current detection object 100 inside the coil 14. Can be detected.

  FIG. 4 shows the relationship between the frequency of the current flowing through the current detection object and the detection sensitivity of the magnetic field generated from the current detection object. The detection sensitivity of the magnetic field generated from the current detection target is the magnitude of the induced electromotive force generated by the magnetic field generated from the current detection target acting on the coil 14, that is, the current detector 10 is the current detection target. The sensitivity to detect the current flowing through As shown in FIG. 4, the detection sensitivity of the magnetic field generated from the current detection target increases as the frequency of the current flowing through the current detection target increases. According to the experiment by the inventors, the current detection object is indirectly detected by connecting the current detection object to the configuration of the present embodiment, that is, the current line portion 12 that penetrates the coil 14. Even in the configuration, the same tendency as shown in FIG. 4 can be obtained in the configuration in which the current detection target is passed through the opening provided inside the coil and the current flowing through the current detection target is directly detected. Was confirmed.

Further, as described above, the slit 15 a is preferably formed within the range where the coil 14 exists in the thickness direction of the current detector 10. Thereby, it can avoid that the detection sensitivity of the magnetic field by the coil 14 falls remarkably.
Further, as described above, the slit 15 a preferably has an opening width equal to or smaller than the thickness of the coil 14 in the thickness direction of the current detector 10. Thereby, the shielding effect of the external magnetic field and the external electric field by the shield part 15 can be sufficiently ensured. It has been confirmed by the inventor's experiment that the opening width of the slit 15a can be suppressed if the opening width of the coil 14 is at least 50 μm or more regardless of the thickness of the coil 14. If the type of current detection coil, current detection performance, shape, configuration, size, etc. are different, even if the opening width of the slit 15a is 50 μm or less, a decrease in magnetic field detection sensitivity due to the coil can be suppressed. There may be cases.

  In this embodiment, since the mounting parts 12a and 12b of the current line part 12 protrude outward from the side part of the board part 11, a current is supplied to a circuit board (not shown) on which the current detection object 100 is mounted. This is effective when the detector 10 is mounted vertically.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. Only the differences from the first embodiment will be described below. As shown in FIG. 5, the current detector 20 includes a current line unit 22 that replaces the current line unit 12 described above. The current line portion 22 is made of a linear conductor, and has mounting portions 22 a and 22 b at both ends protruding outward from the lower portion of the substrate portion 11.
According to this configuration, since the mounting portions 22a and 22b of the current line portion 22 protrude outward from the lower portion of the substrate portion 11, a current is supplied to a circuit board (not shown) on which the current detection target 100 is mounted. This is effective when the detector 20 is mounted horizontally.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. Only differences from the second embodiment will be described below. As shown in FIG. 6, the current detector 30 includes a current line portion 32 that replaces the current line portion 22 described above. The current line portion 32 is made of a linear conductor, and has mounting portions 32 a and 32 b at both ends protruding outward from the lower portion of the substrate portion 11. And the distance between these mounting parts 32a and 32b is provided shorter than the distance between the mounting parts 22a and 22b shown in 2nd Embodiment, In this case, the mounting part 22a is the center part of the current detector 30. Is located below the opening 30a provided so as to penetrate the inside of the coil 14 in the axial direction.

According to this configuration, since the mounting portions 32a and 32b of the current line portion 32 protrude outward from the lower portion of the substrate portion 11, a current is supplied to a circuit board (not shown) on which the current detection target 100 is mounted. This is effective when the detector 30 is mounted horizontally.
Furthermore, since the opening 30a is provided at the substantially central portion of the current detector 30 so as to face the mounting portion 32a located at the substantially central portion of the lower portion of the current detector 30, the user can pass through the opening 30a. The operation of soldering the mounting portion 32a can be performed. Thereby, even if it is the structure where the mounting part 32a exists in the substantially center part of the lower part of the current detector 30, ie, the position where soldering is difficult, the current detector 30 can be easily mounted.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIG. Only the differences from the first embodiment will be described below. As shown in FIG. 7, the current detector 40 includes a coil 44 that replaces the above-described coil 14 and a shield portion 45 that replaces the shield portion 15.
The dimension between the inner side and the outer side of the coil 44 is formed shorter than the dimension between the inner side and the outer side of the coil 14 of the first embodiment. Further, the shield portion 45 is also formed such that the dimension between the inner side and the outer side is the dimension between the inner side and the outer side of the shield portion 15 of the first embodiment along the entire circumference of the coil 44 formed smaller. It is formed shorter. The coil 44 also has a winding part 44d spirally wound in the circumferential direction of the current detector 40, and a return line part 44c extending in the circumferential direction inside the winding part 44d, and a laminated substrate. And is configured as a so-called laminated type Rogowski coil.

  In addition, the current detector 40 includes a current line unit 42 that replaces the current line unit 12 described above. The current line portion 42 is made of a linear conductor, and has mounting portions 42 a and 42 b at both end portions protruding outward from the side portion of the substrate portion 11. Further, the current line portion 42 has an approximately center portion along the inner side surface of the shield portion 45 covering the inside of the coil 44, and the inside of the coil 44 and the shield portion 45 is disposed inside the coil 44 and the shield portion 45. It penetrates along the axial direction. As a result, the current line portion 42 is formed such that the entire length thereof, that is, the distance between the mounting portions 42a and 42b is shorter than the entire length of the current line portion 12 described above. Further, the shield part 45 described above has a slit 45 a in a part covering the inner peripheral part of the coil 44. The slit 45 a extends in an annular shape along the circumferential direction of the coil 44, and opens between the coil 44 and the current line portion 42.

  Since the current line portion made of a conductor has an inductance component, it is preferable to make the inductance component of the current line portion as low as possible. According to this embodiment, by forming the coil 44 and the shield part 45 to be small, the current line part 42 can be shortened as much as possible, and thereby the inductance component of the current line part 42 can be kept low. The coil 44 can be reduced to a size that does not impair its current detection function, and the shield portion 45 can cover the coil 44 and does not impair the shielding function of the external magnetic field. Can be reduced to size.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to FIG. Only the differences from the first embodiment will be described below. As shown in FIG. 8, the current detector 50 includes a coil 54 that replaces the above-described coil 14, and a shield portion 55 that replaces the shield portion 15.
The coil 54 has a dimension between the inner side and the outer side in a part thereof shorter than a dimension between the inner side and the outer side in the other part, and between the inner side and the outer side of the coil 14 of the first embodiment. It is shorter than the dimension. That is, the coil 54 has a non-uniform dimension between the inside and the outside. Further, the shield portion 55 is also formed between the inner side and the outer side of the portion that covers a part of the coil 54, that is, the portion of the coil 54 that covers the shortest dimension between the inner side and the outer side. Is shorter than the dimension between the inner side and the outer side in the other part, and shorter than the dimension between the inner side and the outer side of the shield part 15 of the first embodiment. In other words, the shield portion 55 has a non-uniform dimension between the inside and the outside. The coil 54 also has a winding portion 54d that is spirally wound in the circumferential direction of the current detector 50, and a return line portion 54c that extends in the circumferential direction in the winding portion 54d. And is configured as a so-called laminated type Rogowski coil.

  Further, the current detector 50 includes a current line unit 52 instead of the above-described current line unit 12. The current line portion 52 is made of a linear conductor, and has mounting portions 52 a and 52 b at both ends protruding outward from the side portion of the substrate portion 11. Further, the current line portion 52 has a substantially central portion along the inner side surface of the shield portion 55 that covers the portion of the coil 54 where the dimension between the inner side and the outer side is the shortest. The inside of the portion 55 is penetrated along the axial direction of the coil 54 and the shield portion 55. Thereby, the current line part 52 is formed so that the total length thereof, that is, the distance between the mounting parts 52a and 52b is shorter than the total length of the current line part 12 described above. Further, the shield part 55 described above has a slit 55 a in a part covering the inner peripheral part of the coil 54. The slit 55 a extends in an annular shape along the circumferential direction of the coil 54, and opens between the coil 54 and the current line portion 52.

  Also in this embodiment, the current line part 52 can be shortened as much as possible by forming a part of the coil 54 and a part of the shield part 55 covering the part so that the inductance component of the current line part 52 can be reduced. Can be kept low. A part of the coil 54 can be reduced to a size that does not impair the current detection function, and a part of the shield part 55 that covers the part is between the inner side and the outer side of the coil 54. The portion with the shortest dimension can be covered, and the size can be reduced to a size that does not impair the shielding function of the external magnetic field. In particular, in this embodiment, since only a part of the coil 54 is formed to be small, a part of the coil 54 is formed smaller than the coil 44 of the fourth embodiment while maintaining the current detection function of the coil 54 as a whole. Is possible. Further, since only a part of the shield part 55 is formed to be small, a part of the shield part 55 is formed smaller than the shield part 45 of the fourth embodiment while maintaining the external magnetic field shielding function as the whole shield part 55. It is possible. Therefore, the current line part 52 can be made shorter than the current line part 42 of the fourth embodiment, and thereby the inductance component of the current line part 52 can be further reduced.

(Other embodiments)
The present invention is not limited to the above-described embodiments, and can be applied to various embodiments without departing from the gist thereof. For example, the present invention can be modified or expanded as follows.
The coils 14, 44, 54 are not limited to so-called Rogowski coils, and various coils can be adopted. For example, a current transformer may be used. In short, any coil may be used as long as it is formed in an annular shape and can detect a current flowing through a current line portion penetrating the inside. The coils 14, 44, 54 are not limited to an annular shape, and may be formed in an elliptical shape, a rectangular shape, or a polygonal shape, for example.
The number of insulating substrates constituting the substrate unit 11 is not limited to twelve. In short, it is preferable that the substrate unit 11 is composed of a laminated substrate in which a plurality of substrates are laminated.
A plurality of slits 15a, 45a, and 55a may be provided in portions of the shield portions 15, 45, and 55 that cover the inner portions of the coils 14, 44, and 45, respectively.

The opening widths of the slits 15a, 45a, and 55a can be appropriately changed and set according to the type of the current detection coil, the current detection performance, the shape, the configuration, the size, and the like.
The slits 15a, 45a, 55a are, in short, extending annularly along the coils 14, 44, 54 in the portions of the shield portions 15, 45, 55 that cover the inner portions of the coils 14, 44, 54. , 44, 54 and the current line portions 22, 42, 52 can be used in various configurations.
You may implement combining several embodiment mentioned above.

  In the drawings, 10, 20, 30, 40 and 50 are current detectors, 11 is a substrate portion (laminated substrate), 12, 22, 32, 42 and 52 are current line portions, 12a and 12b are mounting portions, and 22a and 22b. Is a mounting part, 32a and 32b are mounting parts, 42a and 42b are mounting parts, 52a and 52b are mounting parts, 14, 44 and 54 are coils, 14c, 44c and 54c are return wire parts, and 14d, 44d and 54d are windings. The line part is shown.

Claims (6)

A current detection coil (14, 44, 54) formed in an annular shape;
A current line portion (12, 22) having a mounting portion (12a, 12b, 22a, 22b, 32a, 32b, 42a, 42b, 52a, 52b) at both ends that penetrates the inside of the coil and is connected to the current detection object. , 32, 42, 52),
A current detector.   The current detector according to claim 1, wherein the current line portion is provided so as to pass through an inner side of the coil and to shorten a distance between the both mounting portions. The coil (44) is formed with a short dimension between the inner side and the outer side over its entire circumference,
The said current line part (42) is provided so that the distance between both said mounting parts (42a, 42b) may become short by penetrating the said coil along the inner side of this coil. The current detector described in 1. The coil (54) is formed such that the dimension between the inner side and the outer side in a part thereof is shorter than the dimension between the inner side and the outer side in other parts,
The said current line part (52) penetrates the said coil so that the dimension between the inner side and the outer side among these coils may become the shortest, and the said mounting parts (52a, 52b) The current detector according to claim 2, which is provided so that a distance therebetween is shortened. The coil (14, 44, 54)
A winding portion (14d, 44d, 54d) spirally wound in the circumferential direction;
A return line portion (14c, 44c, 54c) extending in the circumferential direction in the winding portion;
The current detector according to claim 1, comprising:   The current detector according to any one of claims 1 to 5, wherein the coil is provided on a laminated substrate (11) in which a plurality of substrates are laminated.

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