Current sensor

Abstract

To provide a power line mounting type current sensor capable of minimizing an influence of noise while maintaining high sensitivity when measuring current at a commercial frequency and reducing its size.SOLUTION: A current sensor comprises: a sensor section that is formed so as to pass through an insulating layer and a conductive layer of a board including the insulating layer, and the conductive layer formed on both the surfaces of the insulating layer, and includes multiple via holes having a conductive film on an inner wall, and at least one coil formed from line patterning formed so as to electrically connect the multiple via holes to the conductive layer; a circuit section that is disposed so as to be close to the sensor section and outputs a detection signal of the sensor section to the outside; and a connection section for electrically connecting the sensor section and the circuit section. The circuit section is disposed close to the sensor section so as to minimize the length of a line orthogonal to the center axis of the coil, of the lines that constitute the connection section.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a current sensor. [Background technology]

[0002] Accurate measurement of the current flowing through power lines is an important factor in maximizing the efficiency of power usage based on the prediction and analysis of power demand, and in protecting the power system through the detection of fault currents and the rapid isolation of faulty systems.

[0003] Sensors for detecting the current flowing through the conductor to be measured can be divided into resistance detection methods that use shunt resistors and magnetic field detection methods that use the magnetic field around the conductor. Of these, magnetic field detection methods can be divided into sensors that use current transformers (CTs) and sensors that use Hall elements.

[0004] CT elements use the principle of a transformer, so they are primarily used to measure AC currents, which change over time. When a current flows through a conductor, a magnetic field is generated around it, and if a conductor is placed inside a ring-shaped CT, an induced current will flow in the CT coil due to the magnetic field around the conductor.

[0005] A Hall element is an element that utilizes the Hall effect, whereby when a magnetic field is applied in a direction perpendicular to the current, an electromotive force is generated in a direction perpendicular to the current and the magnetic field.Sensors that utilize this Hall effect are called Hall sensors, and they generate a detection signal when the magnetic field of a magnetic object changes.

[0006] Rogowski coil current sensors, another type of magnetic field detection method, measure current by converting the voltage induced in an air-core coil by the AC magnetic field generated around the current being measured. That is, the magnetic field caused by the AC current flowing through the measurement conductor (primary side) interlinks with the air-core coil, generating an induced voltage in the air-core coil. This induced voltage is the time differential of the current being measured, so by passing it through an integrator, a signal proportional to the current being measured is output.

[0007] In yet another method, a current sensor is known in which a sensor unit is positioned at a predetermined distance from a power conductor through which an AC current flows, and the sensor unit measures electromagnetic waves generated by an induced electromotive force generated by the AC current flowing in the power conductor to detect the AC current (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Korean Patent Publication No. 10-1981640 [Patent Document 2] Korean Patent Publication No. 10-0897229 [Patent Document 3] Japanese Patent Publication No. 2015-200631 Summary of the Invention [Problem to be solved by the invention]

[0009] In order to miniaturize a current sensor, it is possible to use, for example, the current sensor described in Patent Document 1 or a current sensor that uses a Hall element. However, the current sensor described in Patent Document 1 has a sensor section that is made up of a non-coil measurement conductor arranged alongside the power conductor, which poses a problem of significantly reduced measurement sensitivity for low currents (for example, 1 A or less).

[0010] Current sensors that use Hall elements require a magnetic core, which limits their miniaturization (see, for example, Patent Document 2), and because they react sensitively to magnetic signals, they are vulnerable to noise. Unless noise is completely shielded, induced magnetism generated when adjacent bus bars are active can affect the sensor as noise, increasing measurement errors.

[0011] Furthermore, in most cases, magnetic field detection type current sensors have a configuration in which the power line passes through the inside of the core, making it difficult to mount them in a simple manner on existing power lines and requiring a large mounting area.

[0012] From the perspective of mounting area, a printed circuit board with a CT function has been disclosed to eliminate the spatial constraints of attaching it to a power line. However, since this is intended for high-frequency power in the RF (Radio Frequency) band, which has frequencies from several hundred kHz to several GHz, it is possible to detect current even if a metal shielding section is placed between the power line and the coil to block the electric field (see, for example, Patent Document 3).

[0013] However, in the case of low-frequency power having a commercial frequency (power frequency or commercial frequency) of 50 Hz or 60 Hz, unlike high-frequency power in the RF band, the level of the induced current due to the magnetic flux generated from the power line is not significantly different from the surrounding (atmospheric) noise level, so it is not easy to measure the current flowing in the power line using a structure such as the printed circuit board with CT function described in Patent Document 3.

[0014] The present invention has been made in consideration of these points, and aims to provide a current sensor that can minimize the effects of noise while maintaining high sensitivity when measuring commercial frequency currents, and that can reduce the size of the sensor itself.

[0015] The problems to be solved by the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by a person having ordinary skill in the art from the following description. [Means for solving the problem]

[0016] In at least one embodiment of the present invention, there is provided a current sensor comprising: a substrate including an insulating layer and conductor layers formed on both sides of the insulating layer; a sensor unit including a plurality of via holes having conductive films on their inner walls formed to penetrate the insulating layer and the conductor layer; and at least one coil formed by line patterning formed to electrically connect the plurality of via holes to the conductor layer; a circuit unit disposed adjacent to the sensor unit for outputting a detection signal of the sensor unit to the outside; and a connection unit for electrically connecting the sensor unit and the circuit unit, wherein the circuit unit is disposed adjacent to the sensor unit so as to minimize the length of the lines constituting the connection unit that are perpendicular to the central axis of the coil.

[0017] In at least one embodiment of the present invention, there is provided a current sensor comprising: a substrate including an insulating layer and conductor layers formed on both sides of the insulating layer; a plurality of via holes having conductive films on their inner walls formed to penetrate the insulating layer and the conductor layer; and at least one coil formed by line patterning formed to electrically connect the plurality of via holes to the conductor layer; a circuit section disposed adjacent to the sensor section for outputting a detection signal of the sensor section to the outside; and a connection section for electrically connecting a signal output terminal of the sensor section to a signal input terminal of the circuit section, wherein the signal output terminal of the sensor section is formed at a position that minimizes the length of the line from an end of the coil to the signal input terminal of the circuit section, which is perpendicular to the central axis of the coil.

[0018] In at least one embodiment of the present invention, there is provided a current sensor comprising: a substrate including an insulating layer and conductor layers formed on both sides of the insulating layer; a sensor unit including a plurality of via holes having conductive films on their inner walls formed to penetrate the insulating layer and the conductor layer; and at least one coil formed by line patterning formed to electrically connect the plurality of via holes to the conductor layer; and a signal output terminal for outputting a detection signal from the sensor unit, wherein the signal output terminal is formed at a position that minimizes the length of the line from an end of the coil to the signal output terminal that is perpendicular to the central axis of the coil.

[0019] In at least one embodiment of the present invention, the current sensor further comprises a circuit section arranged in close proximity to the sensor section for outputting the detection signal of the sensor section to the outside, and a connection section for electrically connecting the sensor section and the circuit section, and the circuit section is arranged in close proximity to the sensor section so as to minimize the length of the lines constituting the connection section that are perpendicular to the central axis of the coil.

[0020] In at least one embodiment of the present invention, the sensor unit includes a plurality of coils connected in series or in parallel to each other, and the plurality of coils are arranged so as to minimize the length of the lines connecting the plurality of coils in series or in parallel that are perpendicular to the direction of the central axes of the plurality of coils.

[0021] In at least one embodiment of the present invention, the coil includes an iron core at its center.

[0022] In at least one embodiment of the present invention, the sensor unit and the circuit unit are formed on the same substrate.

[0023] In at least one embodiment of the present invention, the sensor unit and the circuit unit are formed on a first substrate and a second substrate, respectively, and the first substrate and the second substrate are arranged to overlap each other in a normal direction.

[0024] In at least one embodiment of the present invention, the circuit section includes at least a low-pass filter and an amplifier.

[0025] In at least one embodiment of the present invention, the current sensor further includes a mounting member made of an insulating material, configured in a box shape to accommodate both the sensor unit and the circuit unit therein, and having a fastening portion on its outer surface for fastening to the power line.

[0026] In at least one embodiment of the present invention, the current sensor further includes a box-shaped shielding case made of a conductive material and having an opening on a first side to accommodate both the sensor unit and the circuit unit therein.

[0027] In at least one embodiment of the present invention, the current sensor further includes a mounting member made of an insulating material, configured in a box shape with one open side so that the opening of the shielding case can be inserted therein, and having a fastening portion on an outer surface for fastening to the power line. [Effects of the Invention]

[0028] According to at least one embodiment of the present invention, it is possible to provide a current sensor that can minimize the influence of noise while maintaining high sensitivity when measuring power frequency current, and that can reduce the size of the sensor itself.

[0029] The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a schematic diagram illustrating a state in which a current sensor according to at least one embodiment of the present invention is attached to a power line. [Figure 2] 1 is a schematic diagram illustrating a state in which a current sensor according to at least one embodiment of the present invention is attached to a power line. [Figure 3]1 is a schematic diagram illustrating a state in which a current sensor according to at least one embodiment of the present invention is attached to a power line. [Figure 4] 1 is a perspective view of a sensor portion of a current sensor in accordance with at least one embodiment of the present invention; [Figure 5] 1 is a plan view showing a first surface and a second surface of a sensor part of a current sensor in accordance with at least one embodiment of the present invention. [Figure 6] 1 is a perspective view illustrating a coil configuration of a sensor portion of a current sensor in accordance with at least one embodiment of the present invention; [Figure 7] FIG. 1 is an exploded perspective view of a current sensor in accordance with at least one embodiment of the present invention. [Figure 8] 1 is a perspective view illustrating a process of attaching a current sensor according to at least one embodiment of the present invention to a power line; [Figure 9] 1 is a perspective view showing a state in which a current sensor according to at least one embodiment of the present invention is attached to a power line; [Figure 10] 1 is an exploded perspective view illustrating an assembly process of a current sensor according to at least one embodiment of the present invention. [Figure 11] 1 is a side cross-sectional view showing a state in which a current sensor according to at least one embodiment of the present invention is attached to a power line. [Figure 12] 1 is a side view illustrating a configuration in which a current sensor according to at least one embodiment of the present invention is attached to a power line; [Figure 13] 1 is a measurement graph for comparing the current sensing performance of a current sensor according to at least one embodiment of the present invention and a current sensor described in Patent Document 1. [Figure 14] 1 is a measurement graph illustrating noise characteristics of a current sensor in accordance with at least one embodiment of the present invention. [Figure 15] 1 is a measurement graph illustrating the non-saturation characteristics of a current sensor in accordance with at least one embodiment of the present invention. [Figure 16] 1 is a perspective view illustrating a coil configuration of a sensor portion of a current sensor in accordance with at least one embodiment of the present invention; [Figure 17]1 is a perspective view illustrating a coil configuration of a sensor portion of a current sensor in accordance with at least one embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0031] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A power line mounted current sensor according to at least one embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0032] FIG. 1 is a schematic diagram showing a state in which a current sensor 100 according to at least one embodiment of the present invention is attached to a power line (e.g., a busbar) P. FIG. 2 is a schematic diagram showing a state in which a current sensor 200 according to at least one embodiment of the present invention is attached to a power line P. FIG. 3 is a schematic diagram showing a state in which a current sensor 300 according to at least one embodiment of the present invention is attached to a power line P.

[0033] In Figures 1 to 3, (a) is a perspective view close to a plan view of the current sensor attached to the power line P as seen from above, and (b) is a side view of the current sensor attached to the power line P as seen from the side.

[0034] The current sensor 100 shown in Figure 1 is composed of a substrate 110 including conductor layers formed on both sides of an insulating layer with the insulating layer sandwiched therebetween, a sensor unit 120 formed on the substrate 110, a circuit unit 130 formed on the same substrate 110 as the sensor unit 120, which receives the output from the sensor unit 120 and outputs a current signal representing the magnitude of the current flowing in the power line after performing predetermined signal processing, and a connection unit 140 for electrically connecting the sensor unit 120 and the circuit unit 130.

[0035] When a current flows through the power line P, a magnetic field is formed around the power line P, and the sensor unit 120 detects the magnetic flux flowing along the magnetic field and outputs a signal representing the magnitude of the current flowing through the power line P.

[0036] At this time, the sensor unit 120 detects the magnetic flux caused by the low-frequency current flowing through the power line P, and the level of the detected signal is not significantly different from the level of noise (in the atmosphere) around the power line P. Therefore, in order to minimize the effect of noise on the signal level of the sensor unit 120, it is necessary to form a line parallel to the power line P inside the current sensor 100 as short as possible.

[0037] The lines inside current sensor 100 or the lines constituting connection portion 140 may be lines perpendicular to power line P, lines parallel to power line P, or diagonal lines forming a predetermined angle with respect to power line P. Here, "forming lines parallel to power line P as short as possible" means, taking into account diagonal lines forming a predetermined angle with respect to power line P, "shortening the length of the lines of vector components parallel to power line P," and in this specification, the lines parallel to power line P and the vector components of diagonal lines forming a predetermined angle with respect to power line P are collectively referred to as "lines parallel to power line P."

[0038] Therefore, "minimizing the length of the line parallel to the power line P" or "minimizing the length of the line perpendicular to the central axis of the coil" as described below includes minimizing at least one of (A) "the length of the line parallel to the power line P or the line perpendicular to the central axis of the coil," (B) "the length of the vector component perpendicular to the central axis of the coil on the power line P or the line diagonal to the central axis of the coil," or "the sum of the length of (A) and the length of (B)."

[0039] In other words, by minimizing the length of the output end line of the sensor unit 120 and the connection unit 140 that electrically connects the sensor unit 120 and the circuit unit 130 (by minimizing the distance from the sensor unit 120 to the circuit unit 130), the signal detection efficiency of the sensor unit 120 can be improved.

[0040] The current sensor 200 shown in Figure 2 is composed of a substrate 210 including conductor layers formed on both sides of an insulating layer with the insulating layer sandwiched therebetween, a sensor unit 220 formed on the substrate 210, a circuit unit 230 formed on the same substrate 210 as the sensor unit 220, which receives the output from the sensor unit 220 and outputs a current signal representing the magnitude of the current flowing in the power line after predetermined signal processing, and a connection unit 240 for electrically connecting the sensor unit 220 and the circuit unit 230.

[0041] While the current sensor 100 shown in FIG. 1 is composed of a sensor unit 120, a circuit unit 130, and a connection unit 140 for electrically connecting the sensor unit 120 and the circuit unit 130 in the longitudinal direction of the power line P, the current sensor 200 shown in FIG. 2 is similar in that the sensor unit 220 and the circuit unit 230 are formed on the same substrate 210, but the sensor unit 220 and the circuit unit 230 are arranged in a direction intersecting (or perpendicular to) the longitudinal direction of the power line P, and the connection unit 240 is configured to electrically connect the sensor unit 220 and the circuit unit 230 in a direction intersecting (or perpendicular to) the longitudinal direction of the power line P.

[0042] In the current sensor 200 shown in FIG. 2, the current sensor itself (more precisely, the circuit section 230) protrudes from the power line P, requiring more space on the side of the power line P, but since it can reduce the number of lines parallel to the power line P compared to the current sensor 100 shown in FIG. 1, it is possible to further improve the signal detection efficiency of the sensor section 220.

[0043] The current sensor 300 shown in Figure 3 is composed of a first substrate 310 including conductor layers formed on both sides of an insulating layer with the insulating layer sandwiched between them, a sensor unit 311 formed on the first substrate 310, a second substrate 320 including conductor layers formed on both sides of the insulating layer with the insulating layer sandwiched between them, a circuit unit 321 formed on the second substrate 320, which receives the output from the sensor unit 311 and outputs a current signal representing the magnitude of the current flowing in the power line after predetermined signal processing, and a connection unit 340 for electrically connecting the sensor unit 311 and the circuit unit 321.

[0044] 1 and current sensor 200 shown in Fig. 2 have a structure in which the sensor unit and the circuit unit are formed on the same substrate, whereas current sensor 300 shown in Fig. 3 has a structure in which sensor unit 311 and circuit unit 321 are formed on separate, independent substrates and are electrically connected by connecting unit 340 so that they are stacked in a direction perpendicular to the longitudinal direction of power line P. Connecting unit 340 can electrically connect sensor unit 311 and circuit unit 321 and also function to physically fix them together.

[0045] In this way, by forming the sensor unit 311 and the circuit unit 321 on separate substrates and electrically connecting them by the connection unit 340 so that they are stacked in a direction perpendicular to the longitudinal direction of the power line P, it is possible to minimize the distance between the sensor unit 311 and the circuit unit 321 while reducing the number of lines parallel to the longitudinal direction of the power line P, thereby further improving the signal detection efficiency of the sensor unit 311.

[0046] Here, the connection portion 340 must be formed as short as possible (minimize the length) while electrically connecting the sensor portion 311 and the circuit portion 321 and fixing the first substrate 310 and the second substrate 320 so that they are not physically connected.

[0047] As shown in Figures 1 to 3, current sensors 100, 200, and 300 are configured to be surface-mounted on a power line (e.g., a bus bar) P and are configured to detect (measure) induced current due to changes in magnetic flux that occur when current flows through the power line P.

[0048] For this purpose, the current sensors 100, 200, and 300 are configured to include at least one coil formed by a plurality of via holes formed to penetrate the insulating layer and the conductive layer of the substrates 110, 210, and 310 and having a conductive film formed on the inner wall thereof, and a line pattern formed to connect the plurality of via holes to the conductive layer.

[0049] Figures 4 and 5 are actual images of the first substrate 310 manufactured in the form of the current sensor 300 shown in Figure 3, and show examples in which a coil C1 with 7 coils, a coil C2 with 5 coils, a coil C3 with 6 coils, and a coil C4 with 7 coils are formed using multiple via holes 312 and line patterning 313 on a PCB with a thickness of 2 mm and lengths of 7 mm and 22 mm in the y and x directions, respectively.

[0050] In the sensor unit 311 shown in Figures 4 and 5, the coils C1 to C4 are connected in series with each other and configured to maximize the detection of induced electromotive force due to magnetic flux generated by current flowing in the power line P in a substrate 310 of a given size.

[0051] 6 is a perspective view showing a coil formation form of the sensor unit 311 of the current sensor 300 according to at least one embodiment of the present invention. The sensor unit 120 of the current sensor 100 and the sensor unit 220 of the current sensor 200 may also have coils formed in the same form as the sensor unit 311.

[0052] 6, a conductive film 317 is applied inside a plurality of via holes 312 formed in two rows arranged in a zigzag or straight line in a first direction (y direction) on first substrate 310, and therefore, by forming line patterning 313 so that via holes 312 on both sides are electrically connected in a spiral, a coil C1 is formed with a spiral structure between start point S and end point E, having length L and major axis length a, as shown below the arrow in FIG. 6. In this case, the minor axis length b of coil C1 corresponds to the thickness of first substrate 310.

[0053] In at least one embodiment of the present invention, the coils C1 to C4 may include an iron core in the center. While a coil without a core has the characteristic of not saturating, a coil with an iron core has the disadvantage of saturating when the magnetic flux density of the iron core reaches its maximum, but has the advantage of increasing sensitivity.

[0054] In at least one embodiment of the present invention, the substrates 110, 210, 310, 320 include printed circuit boards (PCBs) in which insulating layers and conductive layers are stacked to form a substrate, and a desired circuit can be formed through patterning of the conductive layers.

[0055] In at least one embodiment of the present invention, the via holes are formed in two rows aligned in a first direction (the y direction in the example shown in FIG. 6) as shown in FIG.

[0056] Generally, in the case of low-frequency power with a commercial frequency of 50 Hz or 60 Hz, unlike high-frequency power in the RF band, the level of the induced current due to magnetic flux generated from the power line is not significantly different from the level of surrounding (atmospheric) noise, making it difficult to measure the current flowing through the power line.

[0057] To solve this problem, in at least one embodiment of the present invention, the signal detection efficiency of the sensor unit is increased to a commercial level through the following structure.

[0058] i) When forming a line pattern for forming a coil in the sensor section, the length of the line parallel to the power line or the line perpendicular to the central axis of the coil (for example, a line such as line 318 in FIG. 6) should be made as short as possible (or minimized). ii) The distance between the sensor section and the circuit section is made as short (or minimized) as possible. iii) When the sensor unit and the circuit unit are formed on separate substrates, the output terminal of the sensor unit should be located in the center of the coils or on both ends of the substrate to minimize the influence of lines other than the coils when forming multiple coils. In the latter case, it is sufficient to ensure the shortest distance between the sensor unit and the circuit unit on the circuit unit side. iv) When the sensor unit and the circuit unit are formed on separate substrates, the sensor unit and the circuit unit are arranged adjacent to each other in a direction that intersects (or is perpendicular to) the power line. v) Equipped with a metal box-shaped shielding case to minimize the influence of external noise. vi) Both the sensor unit and the circuit unit are housed in a shielded case. vii) The circuit section includes at least a low pass filter and an amplifier.

[0059] Fig. 7 is an exploded perspective view of a current sensor 700 according to at least one embodiment of the present invention. Fig. 8 is a perspective view showing a process of attaching the current sensor 700 according to at least one embodiment of the present invention to a power line P. Fig. 9 is a perspective view showing a state in which the current sensor 700 according to at least one embodiment of the present invention is attached to a power line P.

[0060] In at least one embodiment of the present invention, the current sensor 700 further includes a box-shaped shielding case 730 made of a conductive (eg, metal) material, with an opening 732 on a first side, as shown in FIG.

[0061] The shielding case 730 according to at least one embodiment of the present invention is a box-shaped member made of a conductive material to block external noise when detecting magnetic flux from a power line that transmits low-frequency (e.g., commercial frequency) power.

[0062] In at least one embodiment of the present invention, the first substrate 310 has L-shaped grooves 316 formed at the four corners of a rectangle, and is formed in a cross shape with the L-shaped grooves 316 protruding from opposite sides.

[0063] The shielding case 730 has recesses 731 on both sides facing the second direction of the opening 732 so that both sides of the first substrate 310 protruding in a second direction (x direction in Figure 6) perpendicular to the first direction are fitted into the recesses 731 of the opening 732, and is configured in such a way that when both sides of the first substrate 310 protruding in the second direction are fitted into the recesses 731 of the opening 732, both sides of the first substrate 310 in the first direction are inserted into the opening 732 and block the opening 732.

[0064] Therefore, when the shielding case 730 is attached to the power line P so that the first substrate 310 is close to the power line P, the shielding case 730 shields the outer surface of the first substrate 310 (the side opposite the power line P), and the power line P itself serves to shield the power line P side.

[0065] With this structure, the sensor unit 311 is shielded on all four sides while allowing the magnetic flux generated when current flows through the power line P to enter the coils C1 to C4 of the sensor unit 311, so it is desirable to set the width (length in the first direction) of the sensor unit 311 to be equal to or smaller than the width of the power line P.

[0066] In at least one embodiment of the present invention, the sensor unit 311 is disposed inside the shielding case 730 in a direction in which the magnetic flux generated by the power line P is transmitted most efficiently, so that the magnetic flux generated by the power line P can be detected efficiently.

[0067] In at least one embodiment of the present invention, as shown in FIG. 7, the current sensor 700 is configured in a box shape with one side open so that the opening 732 side of the shielding case 730 can be inserted, and further includes an insulating mounting member 720 having a fastening portion 721 on its outer surface so that the power line P can be fitted therein.

[0068] The current sensor 700 shown in Figures 7 to 9 is explained using the structure of the current sensor 300 shown in Figure 3 as an example, but the structure of the current sensor 100 shown in Figure 1 or the current sensor 200 shown in Figure 2 can also be applied in the same way.

[0069] 7 shows a state in which the first substrate 310 and the second substrate 320 are fitted into the shielding case 730 and then the shielding case 730 is inserted into the mounting member 720, but if the shielding case 730 is not used, the first substrate 310 and the second substrate 320 can be mounted by pushing them to the bottom of the mounting member 720. In this case, it is not necessary to form the L-shaped grooves 316 at the four corners of the first substrate 310.

[0070] In the example shown in Figures 8 and 9, a plate-type bus bar bent into an L shape, 2 mm thick and 10 mm wide, is used as the power line P, and fastening portions 721 are formed on the side of the mounting member 720 to mount the first board 310 and the second board 320 inserted into the mounting member 720 to the power line P. However, this is merely one example for the purpose of explanation, and by forming fastening portions 721 on the side or bottom of the mounting member 720, it is also possible to apply this to a straight-shaped bus bar, a ring-shaped bus bar, or an electric wire having a predetermined thickness.

[0071] In at least one embodiment of the present invention, the width of the mounting member 720 may be formed wider than the width of the power line P, but it is preferable that the width of each of the coils C1 to C4 constituting the sensor unit 311 is formed to correspond to the width of the power line P.

[0072] Figure 6 shows a configuration in which multiple via holes 312 are formed in two rows arranged in a zigzag pattern in the first direction, but this is an arrangement for connecting the multiple via holes 312 to a spiral coil shape via the line patterning 313, and it is also possible to form the multiple via holes 312 in two rows arranged in a zigzag pattern or in a straight line, as long as the multiple via holes 312 can be electrically connected to a spiral coil shape via the line patterning 313.

[0073] 6, a plurality of via holes 112 are arranged at a first position in the X direction, and a plurality of via holes 112 are arranged at a second position in the X direction. The positions in the Y direction of the plurality of via holes 112 at the first position and the positions in the Y direction of the plurality of via holes 112 at the second position are different, but the positions in the Y direction may be the same.

[0074] In other words, when a plurality of via holes 312 are formed in two rows aligned in a straight line in the first direction, one of the rows may have one more or one less via hole as needed. In any case, the line patterning 313 connects the plurality of via holes 312 with diagonal lines on at least one side, so the term "zigzag" is used. However, as long as they are formed in two rows side by side, the zigzag and straight lines can be considered to be the same form.

[0075] In at least one embodiment of the present invention, the line patterning 313 is formed in the conductor layers on both sides of the insulating layer so as to electrically connect a plurality of via holes 312 formed in two rows aligned in the above sense in a spiral manner, and form coils C1 to C4 with the first direction as the central axis.

[0076] In at least one embodiment of the present invention, first substrate 310 including at least one coil C1-C4 formed by a plurality of via holes 312 and line patterning 313 is configured so that a first surface of first substrate 310 is mounted in proximity to power line P in a direction in which the central axes of coils C1-C4 intersect with the power line P, the power line being the object of current measurement. The "mounted in proximity" configuration is, for example, a configuration in which first substrate 310 is mounted in contact with the inner wall surface of current sensor 700 (or mounting member 720 shown in FIG. 7).

[0077] That is, the current sensor according to at least one embodiment of the present invention can measure the current flowing through a power line by bypassing or attaching the power line, which is the object of current measurement, to the power line in its natural state without cutting the power line, so that the first surface of the sensor unit is adjacent to the power line.

[0078] In Figures 8 and 9, a flat bus bar is illustrated as an example of the power line P, the object of which current is to be measured, but a current sensor according to at least one embodiment of the present invention can be applied to any type of power line, including a flat or annular bus bar, a general conductor, etc.

[0079] In at least one embodiment of the present invention, as shown in Figures 4 and 5, the sensor unit 311 includes multiple coils C1 to C4 whose central axes are formed approximately parallel to each other, and the multiple coils C1 to C4 are connected in parallel or in series.

[0080] The sensor unit 311 senses the amount of current flowing through the power line P based on the induced current induced in the coils C1 to C4, and the greater the amount of induced current, the higher the sensitivity. Therefore, the sensitivity can be improved by connecting multiple coils C1 to C4, each with its central axis parallel to one another, in parallel to increase the amount of induced current, or by connecting them in series to increase the induced electromotive force.

[0081] FIG. 10 is an exploded perspective view illustrating the assembly process of a current sensor in accordance with at least one embodiment of the present invention.

[0082] In at least one embodiment of the present invention, the current sensor is mounted on the second substrate 320, electrically connected to the sensor unit formed on the first substrate 310, and further includes a circuit unit for receiving outputs from the coils C1 to C4 and outputting a current signal representing the magnitude of the current flowing through the power line through predetermined signal processing.

[0083] The example shown in Figure 10 shows a case where the sensor includes a circuit unit mounted on a separate second substrate 320, electrically connected to the sensor unit, receiving outputs from coils C1 to C4, and outputting a current signal representing the magnitude of the current flowing through the power line through predetermined signal processing.

[0084] Here, the second substrate 320 is formed to have the same size as the first substrate 310 excluding both sides protruding in the second direction, and is fastened to the first substrate 310 with a predetermined fastening member and inserted into the shielding case 730.

[0085] Therefore, when the first substrate 310 on which the sensor unit is formed and the second substrate 320 on which the circuit unit is mounted are physically and electrically connected using a predetermined fastening member (e.g., connecting portion 340) and inserted into the shielding case 730 in the direction of the arrow shown in Figure 10, the second substrate 320 is inserted inside the shielding case 730, and the first substrate 310 is attached to the shielding case 730 so that both sides protruding in the second direction are fitted into the recesses 731 and block the opening 732.

[0086] That is, when the first substrate 310 is fitted into the recess 731 of the shielding case 730, the surface L1 of the opening 732 of the shielding case 730 and the outer surface L2 of the first substrate 310 become substantially flush with each other, as shown in FIG.

[0087] In at least one embodiment of the present invention, the current sensor includes a sensor unit including coils C1 to C4 for sensing the current flowing through the power line, a filter unit connected to the output terminal of the sensor unit for removing noise, and a circuit unit including an amplifier unit for amplifying the signal that has passed through the filter unit.

[0088] The coils C1 to C4 of the current sensor are installed close to the power lines through which current flows, and are current sensing units that detect the magnetic field generated by the power lines and output a sinusoidal induced current when it enters the coils.

[0089] The filter section passes the induced current through a low pass filter, which passes low frequency signals based on a certain frequency and removes high frequency signals. The signal that passes through the amplifier section passes through a high pass filter, which removes DC noise and removes signals below a certain frequency.

[0090] The amplifier section amplifies the signal that has passed through the low-pass filter (approximately 1000 times) using a differential amplifier and outputs a sine wave. The amplification rate can be set as needed.

[0091] In at least one embodiment of the present invention, a signal output terminal 322 for outputting a signal from the circuit unit to the outside and a power supply terminal 323 for supplying power to the circuit unit are electrically connected to the first substrate 310 or the second substrate 320.

[0092] In at least one embodiment of the present invention, the shielding case 730 includes a power supply port (not shown) for passing a power line to supply power to the circuit unit, and a signal output port (not shown) for passing a signal output line from the circuit unit.

[0093] In at least one embodiment of the present invention, the fastening portion 721 of the mounting member 720 has a rail-shaped groove into which the power line P is inserted and fastened. That is, the current sensor 700 is configured as shown in Fig. 7, and the plate-shaped power line P is inserted into the rail-shaped groove as shown in Fig. 8, and the current sensor 700 is attached to the power line P so that the sensor portion is close to the power line P as shown in Fig. 9.

[0094] In at least one embodiment of the present invention, the fastening portion 721 of the mounting member 720 has a clip-shaped groove into which the power line P is inserted and fastened.

[0095] This structure is configured so that it can rotate outward, for example, by forming a bent portion (not shown) where the L-shaped portion that supports the power line P from the outside at the fastening portion 721 of the mounting member 720 shown in Figure 7 meets the mounting member 720.

[0096] Therefore, for example, instead of the L-shaped busbars shown in FIGS. 8 and 9, it can also be used in the case of straight-shaped busbars or ring-shaped busbars.

[0097] In at least one embodiment of the present invention, the width of the mounting member 720 corresponds to the width of the power line P, and the width of the first substrate 310 in the first direction is formed to be narrower than the width of the power line P.

[0098] In at least one embodiment of the present invention, the mounting member 720 is formed so that the inner length in a third direction perpendicular to the first and second directions (the inner length from the opening to the bottom) is equal to the outer length in the third direction of the shielding case 730 (the outer length from the opening to the bottom) (see Figures 7 and 8).

[0099] In this way, it is possible to configure the current sensor 700 in which the shielding case 730 including the sensor section and the circuit section and the mounting member 720 are integrated.

[0100] In at least one embodiment of the present invention, the mounting member 720 is formed such that the inner length in a third direction perpendicular to the first and second directions (the inner length from the opening to the bottom) is shorter than the outer length in the third direction of the shielding case 730 (the outer length from the opening to the bottom).

[0101] This structure has the advantage that the shielding case 730 and the mounting member 720 can be easily separated when a problem occurs in the fastening portion 721 of the mounting member 720 or in the sensor portion or circuit portion.

[0102] 11 is a side cross-sectional view showing a state in which a current sensor according to at least one embodiment of the present invention is attached to a power line P. In the example shown in FIG. 11, for convenience of explanation, only the first substrate 310 is shown.

[0103] 11, first substrate 310 having a sensor unit formed thereon is mounted in shielding case 730 so as to cover opening 732, and then shielding case 730 is inserted into mounting member 720 so that first substrate 310 faces inward. When first substrate 310 is mounted on power line P so that it is close to power line P, an induced current is generated when magnetic flux M generated when current flows through power line P passes through coil C of the sensor unit formed on first substrate 310. In other words, coil C of the sensor unit functions as an induction coil that induces magnetic flux M generated when current flows through power line P.

[0104] When an AC current flows through the power line P, magnetic flux M generated around the power line P flows inside the coil C, and the resulting change in magnetic flux inside the coil C is converted into an induced current or induced electromotive force and output. Therefore, the amount of current flowing through the power line P can be measured by calculating this induced current or induced electromotive force.

[0105] In at least one embodiment of the present invention, the shielding case 730 has recesses 731 on both sides facing the second direction of the opening 732 so that both sides protruding in a second direction perpendicular to the first direction of the first substrate 310 are fitted into the recesses 731 of the opening 732, and when both sides protruding in the second direction of the first substrate 310 are fitted into the recesses 731 of the opening 732, both sides in the first direction are inserted into the opening 732 and block the opening 732.Therefore, when the shielding case 730 is attached to the power line P so that the sensor unit is close to the power line P, the shielding case 730 shields the outer surface of the sensor unit (the opposite side of the power line P), and the power line P itself serves to shield the side of the power line P.

[0106] That is, the current sensor according to at least one embodiment of the present invention has a structure in which, when the first substrate 310 is attached to the shielding case 730, which is then inserted into the mounting member 720 and attached to the power line P, the shielding case 730 and the power line P shield the sensor unit in all directions with the bottom surface of the mounting member 720 in between.

[0107] With this structure, the magnetic flux M generated when current flows through the power line P enters the coil C, and at the same time, the sensor unit is shielded on all four sides, so the width of the sensor unit (length in the first direction) must be set to be equal to or smaller than the width of the power line P.

[0108] According to the above-described configuration of the present invention, electromagnetic noise transmitted from outside the power line P is blocked by the shielding case 730, and magnetic changes generated from the power line P are mainly transmitted to the sensor unit inside the shielding case 730, thereby minimizing the influence of external noise.

[0109] FIG. 12 is a side view showing a manner in which a current sensor according to at least one embodiment of the present invention is attached to a power line P.

[0110] (a) of Figure 12 shows a configuration in which the first substrate 310 and the second substrate 320 are electrically connected by the connection part 340, as shown in Figure 9, and the first substrate 310 is mounted so as to be parallel to the power line P and closer to the power line P than the second substrate 320.

[0111] (b) of Figure 12 shows a configuration in which the power line P passes through a through hole formed in a control board 1210 on which an MCU (Micro Controller Unit) 1211 and other components are mounted, and a first substrate 1220 having a sensor unit, a second substrate 1230 having a circuit unit, and a connection portion 1240 for electrically connecting the first substrate 1220 and the second substrate 1230 are formed on the control board 1210.

[0112] That is, (b) of Figure 12 shows a form in which a current sensor is configured using a control board 1210 equipped with an MCU 1211 for detecting the current flowing through the power line P and performing power management, instead of the substrate 110 shown in Figure 1.

[0113] FIG. 13 is a measurement graph for comparing the current sensing performance of a current sensor according to at least one embodiment of the present invention and a current sensor described in Patent Document 1.

[0114] As shown in Figure 13, the sensor output for both sensors increases linearly up to 300 A without saturating. However, when the range below 1 A is enlarged, it can be seen that the sensor output of the current sensor according to at least one embodiment of the present invention continues to increase linearly, whereas the sensor output of the current sensor described in Patent Document 1 does not change.

[0115] In other words, the current sensor according to at least one embodiment of the present invention not only exhibits a linear sensor output as the current increases, but also exhibits a linear sensor output even in the low current range of 1 A or less, and therefore has superior advantages in terms of sensitivity.

[0116] FIG. 14 is a measurement graph illustrating noise characteristics of a current sensor in accordance with at least one embodiment of the present invention.

[0117] The graph shown in Figure 14 shows the output voltage waveform of a current sensor attached to a power line, measured with an oscilloscope when currents of 0 A and 10 A flow through the power line. Generally, current sensors applied to bus bars contain noise so large that it is difficult to identify the shape of a sine wave when the current is 0 A. However, the current sensor according to at least one embodiment of the present invention outputs a clear sine wave even when the current is 0 A, indicating that it is hardly affected by noise.

[0118] FIG. 15 is a measurement graph illustrating the non-saturation characteristics of a current sensor in accordance with at least one embodiment of the present invention.

[0119] The graph shown in Fig. 15 compares the characteristics of a commercial CT rated at 40 / 5A and a current sensor according to at least one embodiment of the present invention. When the current flowing through the power line is increased, the current sensor according to at least one embodiment of the present invention exhibits non-saturation characteristics, while the CT exhibits saturation characteristics from around 50A.

[0120] The current sensors shown in Figures 4 to 6 use a PCB to form a coil through multiple via holes with a conductive film formed on the inner walls and line patterning, but the coil in the sensor section can also be formed from an insulating-coated conductor.

[0121] 16 and 17 are perspective views showing coil configurations of a sensor portion of a current sensor in accordance with at least one embodiment of the present invention.

[0122] As shown in Figure 16, a current sensor according to at least one embodiment of the present invention comprises a substrate 1610 made of an insulating material, two rows of through holes 1612 formed side by side in a first direction (y direction) on the substrate 1610, and a sensor unit including at least one coil C1 formed by spirally winding an insulating coated conductor 1613 through the two rows of through holes 1612 and having a central axis in the first direction.

[0123] A current sensor according to at least one embodiment of the present invention can have the same structure as the current sensor shown in Figures 1 to 12, except that the coil used in the sensor section is formed from an insulating-coated conductor rather than from via holes and line patterning.

[0124] As shown in Figure 17, a current sensor according to at least one embodiment of the present invention is composed of a sensor unit including at least one coil formed on a substrate 1710 as shown in Figure 6 or Figure 16 (in the example shown in Figure 17, two rows of through holes 1712 formed side by side in a first direction on the substrate 1710 and at least one coil C1 formed by spirally winding an insulating coated conductor 1713 through the two rows of through holes 1712 with the first direction as the central axis).

[0125] In at least one embodiment of the present invention, the sensor unit comprises a coil C1 that functions as an induction coil, and may optionally include an iron core 1750. While a coreless coil has the characteristic of not saturating, a coil with an iron core has the disadvantage of saturating when the magnetic flux density of the iron core reaches its maximum, but has the advantage of higher sensitivity.

[0126] The iron core 1750 may be formed, for example, when forming the insulating layers of the substrate 1710, by inserting an iron core member between two insulating layers in accordance with the pattern of the coil C1 and then crimping the two insulating layers together, or by forming a sensor section as shown in Figure 6 or Figure 16, and then drilling a hole inside the coil C1 from the side and inserting the iron core member into the hole.

[0127] In the sensor unit shown in FIGS. 16 and 17, when forming a line pattern for forming a coil, the length of the lines 1618 and 1718 parallel to the power lines is made as short as possible.

[0128] As described above, according to at least one embodiment of the present invention, it is possible to provide a current sensor that can minimize the influence of noise while maintaining high sensitivity when measuring power frequency currents, and that can reduce the size of the sensor itself.

[0129] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention. [Explanation of symbols]

[0130] 100, 200, 300, 700: Current sensor 110, 210: Substrate 120, 220, 311: Sensor section 130, 230, 321: Circuit section 140, 240, 340: Connection part 310: First substrate 320: Second board 312: Via Hole 313: Line patterning 314: Sensor output terminal 316: L-shaped groove 317: Conductive film 322: Signal output terminal 323: Power supply terminal 720: Mounting material 730: Shielding case 731: Recess 1200: Control board 1211:MCU 1610, 1710: PCB 1612, 1712: Through holes 1613, 1713: Insulated conductor wire C, C1, C2, C3, C4: Coils M: magnetic flux P:Power line

Claims

1. a sensor unit including a substrate including an insulating layer and conductive layers formed on both sides of the insulating layer, a plurality of via holes having conductive films on inner walls formed to penetrate the insulating layer and the conductive layer, and at least one coil formed by line patterning formed to electrically connect the plurality of via holes to the conductive layer; a circuit section disposed adjacent to the sensor section for outputting a detection signal from the sensor section to an external device; A connection portion for electrically connecting the sensor portion and the circuit portion Equipped with the circuit unit is disposed close to the sensor unit so as to minimize the length of the line that constitutes the connection unit and is perpendicular to the central axis of the coil; Current sensor.

2. a sensor unit including a substrate including an insulating layer and conductive layers formed on both sides of the insulating layer, a plurality of via holes having conductive films on inner walls formed to penetrate the insulating layer and the conductive layer, and at least one coil formed by line patterning formed to electrically connect the plurality of via holes to the conductive layer; a circuit section disposed adjacent to the sensor section for outputting a detection signal from the sensor section to an external device; A connection portion for electrically connecting the signal output terminal of the sensor portion and the signal input terminal of the circuit portion. Equipped with the signal output terminal of the sensor unit is formed at a position that minimizes the length of a line from an end of the coil to the signal input terminal of the circuit unit that is perpendicular to the central axis of the coil; Current sensor.

3. a sensor unit including a substrate including an insulating layer and conductive layers formed on both sides of the insulating layer, a plurality of via holes having conductive films on inner walls formed to penetrate the insulating layer and the conductive layer, and at least one coil formed by line patterning formed to electrically connect the plurality of via holes to the conductive layer; a signal output terminal for outputting a detection signal from the sensor unit Equipped with the signal output terminal is formed at a position that minimizes the length of a line from an end of the coil to the signal output terminal that is perpendicular to the central axis of the coil; Current sensor.

4. a circuit section disposed adjacent to the sensor section for outputting a detection signal from the sensor section to an external device; A connection portion for electrically connecting the sensor portion and the circuit portion Furthermore, the circuit unit is disposed close to the sensor unit so as to minimize the length of the line that constitutes the connection unit and is perpendicular to the central axis of the coil; The current sensor according to claim 3 .

5. the sensor unit includes a plurality of coils connected in series or in parallel with each other, the plurality of coils are arranged so as to minimize the length of lines connecting the plurality of coils in series or in parallel, the lines being orthogonal to the direction of the central axes of the plurality of coils; 4. The current sensor according to claim 1.

6. The coil includes an iron core at its center.

4. The current sensor according to claim 1.

7. The sensor unit and the circuit unit are formed on the same substrate.

5. The current sensor of claim 1, 2, or 4.

8. the sensor unit and the circuit unit are formed on a first substrate and a second substrate, respectively; The first substrate and the second substrate are arranged to overlap each other in a normal direction.

5. The current sensor of claim 1, 2, or 4.

9. The circuit section includes at least a low-pass filter and an amplifier.

5. The current sensor of claim 1, 2, or 4.

10. The sensor further includes a mounting member made of an insulating material, the mounting member having a box shape that accommodates both the sensor unit and the circuit unit therein and a fastening portion on an outer surface for fastening to a power line through which the sensor unit detects current.

5. The current sensor of claim 1, 2, or 4.

11. a box-shaped shielding case made of a conductive material and having an opening on a first side thereof, for accommodating both the sensor unit and the circuit unit therein; 5. The current sensor of claim 1, 2, or 4.

12. the mounting member is made of an insulating material and has a box-like shape with one side open so that the opening of the shielding case can be inserted therein, and has a fastening portion on an outer surface for fastening to a power line that is the target of current detection by the sensor unit. The current sensor of claim 11.

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