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 Art

[0002] Accurate measurement of the current flowing through a power line is an important factor that enables maximizing power usage efficiency based on prediction and analysis of power demand, detecting fault current, and protecting the power system by quickly isolating the fault system.

[0003] Sensors for sensing the current flowing through a measured conductor are classified, according to their sensing methods, into a resistance detection method using a shunt resistor and a magnetic field detection method using the magnetic field around the conductor. Among them, the magnetic field detection method is further classified into a sensor using a current transformer (CT) and a sensor using a Hall element.

[0004] Since the CT element utilizes the principle of a transformer, it is mainly applied to the measurement of AC current whose current changes over time. When a current flows through a conductor, a magnetic field is formed around it. If the conductor is arranged to pass through the inside of an annular CT, an induced current will flow through the coil of the CT due to the magnetic field around the conductor.

[0005] The Hall element is an element that utilizes the Hall effect in which an electromotive force is generated in a direction orthogonal to both the current and the magnetic field when a magnetic field is applied in a direction orthogonal to the current. A sensor that utilizes such a Hall effect is called a Hall sensor, and a detection signal is generated by a change in the magnetic field of a magnetic object.

[0006] A Rogowski coil type current sensor, which is another form of the magnetic field detection method, measures the current by converting the voltage induced in an air-core coil by an alternating magnetic field generated around the measured current. That is, when the magnetic field generated by the alternating current flowing through the measured conductor (primary side) intersects with the air-core coil, an induced voltage is generated in the air-core coil. Since this induced voltage is the time derivative value of the measured current, a signal proportional to the measured current is output by passing it through an integrator.

[0007] Furthermore, in other methods, a current sensor is known in which a sensor unit is placed at a predetermined distance from a power conductor through which alternating current flows, and the alternating current is detected by measuring the electromagnetic waves generated at the sensor unit by the electromotive force induced by the alternating current flowing through the power conductor (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 [Overview of the project] [Problems that the invention aims to solve]

[0009] To miniaturize the current sensor, for example, it is possible to use the current sensor described in Patent Document 1 or a current sensor using a Hall element. However, the current sensor described in Patent Document 1 has a problem in that the sensor part is composed of a non-coiled measuring wire arranged alongside the power conductor, resulting in a significant decrease in measurement sensitivity at low currents (e.g., 1A or less).

[0010] Current sensors using Hall elements have limitations in miniaturization because they require a magnetic core (see, for example, Patent Document 2). Furthermore, they are highly sensitive to magnetic signals and therefore susceptible to noise. Unless the noise is completely shielded, induced magnetic fields generated from the active state of adjacent busbars can affect the measurement error as noise.

[0011] Furthermore, since magnetic field detection type current sensors almost always have power lines that penetrate the inside of the core, they are not easy to implement by simply attaching them to existing power lines, and they have the disadvantage of requiring a large mounting area.

[0012] From the perspective of mounting area, printed circuit boards with CT functionality have been disclosed to overcome the spatial constraints for mounting on power lines. However, since these target high-frequency power in the RF (Radio Frequency) band with frequencies ranging from several hundred kHz to several GHz, current detection is possible even if a metal shield 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 with a commercial frequency of 50Hz or 60Hz, unlike high-frequency power in the RF band, the level of induced current due to magnetic flux generated from the power line is not significantly different from the surrounding (atmospheric) noise level. Therefore, it is not easy to measure the current flowing through the power line in a structure such as the printed circuit board with CT function described in Patent Document 3.

[0014] This invention has been made in view of these points, and aims to provide a current sensor that minimizes the effects of noise while maintaining high sensitivity when measuring commercial frequency current, 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 can be clearly understood by those with ordinary skill in the art from the following description. [Means for solving the problem]

[0016] In at least one embodiment of the present invention, a current sensor is provided comprising: a sensor section including a substrate having an insulating layer and a conductor layer formed on both sides of the insulating layer, a plurality of via holes having a conductive film on their inner walls, and a line pattern formed in the conductor layer to electrically connect the plurality of via holes, a sensor section including at least one coil formed to penetrate the insulating layer and the conductor layer, a circuit section disposed in close proximity to the sensor section for outputting a detection signal from the sensor section to the outside, and a connection section for electrically connecting the sensor section and the circuit section, wherein the circuit section is disposed in close proximity to the sensor section such that the length of the line perpendicular to the central axis of the coil among the lines constituting the connection section is minimized.

[0017] In at least one embodiment of the present invention, a current sensor is provided comprising: a sensor section including at least one coil formed by a circuit pattern in which a substrate having an insulating layer and a conductive layer formed on both sides of the insulating layer has a plurality of via holes having a conductive film on its inner wall and a plurality of via holes formed so as to electrically connect the plurality of via holes to the conductive layer, the sensor section being positioned close to the sensor section for outputting a detection signal from the sensor section to the outside, and a connection section for electrically connecting the signal output terminal of the sensor section to the 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 perpendicular to the central axis of the coil among the lines from the end of the coil to the signal input terminal of the circuit section.

[0018] In at least one embodiment of the present invention, there are provided a plurality of via holes formed to penetrate an insulating layer and conductor layers formed on both surfaces of the insulating layer of a substrate, each via hole having a conductive film on its inner wall, and at least one or more coils formed by line patterning to electrically connect the plurality of via holes to the conductor layer, a sensor unit including the coils, and signal output terminals for outputting a detection signal of the sensor unit. The signal output terminals are formed at positions that minimize the length of a line orthogonal to the central axis of the coil among the lines from the end of the coil to the signal output terminals, thereby providing a current sensor.

[0019] In at least one embodiment of the present invention, the current sensor further includes a circuit unit disposed close to the sensor unit for outputting the detection signal of the sensor unit to the outside, and a connection unit for electrically connecting the sensor unit and the circuit unit. The circuit unit is disposed close to the sensor unit so as to minimize the length of a line orthogonal to the central axis of the coil among the lines constituting the connection unit.

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

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

[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 so as to overlap each other in the normal direction.

[0024] In at least one embodiment of the present invention, the circuit unit 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, which is box-shaped and houses both the sensor unit and the circuit unit inside, and has a fastening portion for fastening to the power line on the outer surface.

[0026] In at least one embodiment of the present invention, the current sensor further includes a shielding case made of a conductive material, which is box-shaped and has an opening on the first side for housing both the sensor unit and the circuit unit inside.

[0027] In at least one embodiment of the present invention, the current sensor further includes a mounting member made of an insulating material, which is box-shaped with one side open so that the opening of the shielding case can be inserted, and has a fastening portion for fastening to the power line on the outer surface.

Advantages of the Invention

[0028] According to at least one embodiment of the present invention, there is an effect that a current sensor can be provided which minimizes the influence of noise while maintaining high sensitivity when measuring commercial frequency current and can miniaturize 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 should be clearly understood by those with ordinary knowledge in the technical field from the following description.

Brief Description of the Drawings

[0030] [Figure 1] It is a schematic diagram showing a state where a current sensor according to at least one embodiment of the present invention is mounted on a power line. [Figure 2] It is a schematic diagram showing a state where a current sensor according to at least one embodiment of the present invention is mounted on a power line. [Figure 3]This is a schematic diagram showing a current sensor according to at least one embodiment of the present invention attached to a power line. [Figure 4] This is a perspective view of the sensor portion of a current sensor according to at least one embodiment of the present invention. [Figure 5] This is a plan view showing the first and second surfaces of the sensor portion of a current sensor according to at least one embodiment of the present invention. [Figure 6] This is a perspective view showing the coil formation configuration of the sensor portion of a current sensor according to at least one embodiment of the present invention. [Figure 7] This is an exploded perspective view of a current sensor according to at least one embodiment of the present invention. [Figure 8] This is a perspective view showing the process of attaching a current sensor according to at least one embodiment of the present invention to a power line. [Figure 9] This is a perspective view showing a current sensor according to at least one embodiment of the present invention attached to a power line. [Figure 10] This is an exploded perspective view showing the assembly process of a current sensor according to at least one embodiment of the present invention. [Figure 11] This is a side cross-sectional view showing a current sensor according to at least one embodiment of the present invention attached to a power line. [Figure 12] This is a side view showing 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] This is a measurement graph for comparing the current sensing performance of a current sensor according to at least one embodiment of the present invention with that of a current sensor described in Patent Document 1. [Figure 14] This is a measurement graph showing the noise characteristics of a current sensor according to at least one embodiment of the present invention. [Figure 15] This is a measurement graph showing the non-saturation characteristics of a current sensor according to at least one embodiment of the present invention. [Figure 16] This is a perspective view showing the coil formation configuration of the sensor portion of a current sensor according to at least one embodiment of the present invention. [Figure 17]This is a perspective view showing the coil formation configuration of the sensor portion of a current sensor according to at least one embodiment of the present invention. [Modes for carrying out the invention]

[0031] A power line-mounted current sensor according to at least one embodiment of the present invention will be described in detail below with reference to the attached drawings.

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

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

[0034] The current sensor 100 shown in Figure 1 consists of a substrate 110 including conductive layers formed on both sides of an insulating layer with an insulating layer in between, a sensor section 120 formed on the substrate 110, a circuit section 130 formed on the same substrate 110 as the sensor section 120 for receiving the output from the sensor section 120 and outputting a current signal representing the magnitude of the current flowing through the power line via predetermined signal processing, and a connection section 140 for electrically connecting the sensor section 120 and the circuit section 130.

[0035] When current flows through power line P, a magnetic field is formed around 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 power line P.

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

[0037] The lines constituting the internal lines or connection part 140 of the current sensor 100 may include lines perpendicular to the power line P, lines parallel to the power line P, and diagonal lines forming a predetermined angle with respect to the power line P. Here, "making the lines parallel to the power line P as short as possible" means "shortening the length of the vector component lines parallel to the power line P" when considering the diagonal lines forming a predetermined angle with respect to the power line P. In this specification, the vector components of lines parallel to the power line P and diagonal lines forming a predetermined angle with respect to the power line P are collectively referred to as "lines parallel to the power line P".

[0038] Therefore, "minimizing the length of the transmission line parallel to the power line P" or, as described below, "minimizing the length of the transmission line perpendicular to the central axis of the coil" means minimizing at least one of the following: (A) "the length of the transmission line parallel to the power line P or perpendicular to the central axis of the coil", (B) "the length of the vector component perpendicular to the central axis of the coil in the transmission line that is oblique to the power line P or the central axis of the coil", or "the sum of the lengths of (A) and (B)".

[0039] In other words, by minimizing the length of the output terminal line of the sensor unit 120 and the connection part 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 consists of a substrate 210 including conductive layers formed on both sides of an insulating layer with an insulating layer in between, a sensor section 220 formed on the substrate 210, a circuit section 230 formed on the same substrate 210 as the sensor section 220 for receiving the output from the sensor section 220 and outputting a current signal representing the magnitude of the current flowing through the power line via predetermined signal processing, and a connection section 240 for electrically connecting the sensor section 220 and the circuit section 230.

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

[0042] The current sensor 200 shown in Figure 2 requires more space on the side of the power line P because the current sensor itself (more precisely, the circuit section 230) is separated from the power line P. However, compared to the current sensor 100 shown in Figure 1, it is possible to reduce the number of lines parallel to the power line P, thereby improving the signal detection efficiency of the sensor section 220.

[0043] The current sensor 300 shown in Figure 3 consists of a first substrate 310 including conductive layers formed on both sides of an insulating layer with an insulating layer in between, a sensor portion 311 formed on the first substrate 310, a second substrate 320 including conductive layers formed on both sides of an insulating layer with an insulating layer in between, a circuit portion 321 formed on the second substrate 320 for receiving the output from the sensor portion 311 and outputting a current signal representing the magnitude of the current flowing in the power line via predetermined signal processing, and a connection portion 340 for electrically connecting the sensor portion 311 and the circuit portion 321.

[0044] While the current sensor 100 shown in Figure 1 and the current sensor 200 shown in Figure 2 have a structure in which the sensor part and the circuit part are formed on the same substrate, the current sensor 300 shown in Figure 3 has a structure in which the sensor part 311 and the circuit part 321 are formed on separate, independent substrates and are electrically connected by a connector part 340 so as to be stacked in one direction perpendicular to the longitudinal direction of the power line P. The connector part 340 can electrically connect the sensor part 311 and the circuit part 321 and at the same time serve to physically fix them in place.

[0045] In this way, by forming the sensor unit 311 and the circuit unit 321 on separate substrates and electrically connecting them with the connection unit 340 so that they are stacked in one direction perpendicular to the longitudinal direction of the power line P, the distance between the sensor unit 311 and the circuit unit 321 can be minimized 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 section 340 needs to be formed as short as possible (minimize its length) while electrically connecting the sensor section 311 and the circuit section 321, and at the same time fixing the first substrate 310 and the second substrate 320 so that they do not physically connect.

[0047] As shown in Figures 1 to 3, the current sensors 100, 200, and 300 are configured to be surface-mounted on a power line (e.g., a busbar) P and to detect (measure) the induced current caused by the change in magnetic flux that occurs 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 with a conductive film formed on their inner walls, which penetrate the insulating layer and conductive layer of the substrates 110, 210, and 310, and by a line pattern formed to connect the plurality of via holes to the conductive layer.

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

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

[0051] Figure 6 is a perspective view showing the coil formation configuration of the sensor portion 311 of the current sensor 300 according to at least one embodiment of the present invention. The sensor portion 120 of the current sensor 100 and the sensor portion 220 of the current sensor 200 can also be formed into coils in the same configuration as the sensor portion 311.

[0052] As shown in Figure 6, a conductive film 317 is applied inside multiple via holes 312 formed in two rows on the first substrate 310 in a zigzag or straight line in the first direction (y direction). If a line pattern 313 is formed so that the via holes 312 on both sides are electrically connected in a helical manner, a coil C1 is formed with a helical structure between a starting point S and an ending point E, having a length L and a major axis length a, as shown below the arrow in Figure 6. At this time, the minor axis length b of the coil C1 corresponds to the thickness of the first substrate 310.

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

[0054] In at least one embodiment of the present invention, the substrates 110, 210, 310, and 320 include a printed circuit board (PCB) in which an insulating layer and a conductive layer are laminated in the shape of a substrate, and a desired circuit can be formed by patterning the conductive layer.

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

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

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

[0058] i) When forming the line pattern for coil formation in the sensor section, the length of lines parallel to the power lines or lines perpendicular to the central axis of the coil (for example, lines like line 318 in Figure 6) is made as short as possible (or minimized). ii) Make the distance between the sensor and the circuit as short as possible (or minimize it). iii) When the sensor and circuit sections are formed on separate circuit boards, in order to minimize the influence of lines other than the coils when forming multiple coils, the output terminal of the sensor section should be positioned in the center of the multiple coils, or the output terminals should be positioned at opposite ends of the circuit board. In the latter case, the shortest distance between the sensor and circuit sections should be ensured on the circuit section side. iv) When the sensor unit and the circuit unit are formed on separate substrates, the sensor unit and the circuit unit are arranged to be close to each other in one direction that intersects (or is perpendicular to) the power lines. 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 comprises at least a low-pass filter and an amplifier.

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

[0060] In at least one embodiment of the present invention, the current sensor 700 further comprises a box-shaped shielding case 730 made of a conductive (e.g., metal) material having an opening 732 on the first side, as shown in Figure 7.

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

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

[0063] The shielding case 730 has recesses 731 on both sides facing the second direction of the opening 732 such that both sides of the first substrate 310 protruding in a second direction (the x-direction in Figure 6) perpendicular to the first direction are fitted into the recesses 731 of the opening 732. 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, thereby closing the opening 732.

[0064] Therefore, when the shielding case 730 is attached to the power line P such 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 acts as a shield on the power line P side.

[0065] In this structure, the magnetic flux generated when current flows through the power line P enters the coils C1 to C4 of the sensor unit 311, while shielding all four sides of the sensor unit 311. Therefore, it is desirable to set the width (length in the first direction) of the sensor unit 311 to be less than or equal to the width of the power line P.

[0066] In at least one embodiment of the present invention, the sensor unit 311 inside the shielding case 730 is positioned in a direction that best transmits the magnetic flux generated in the power line P, so that the magnetic flux generated in the power line P can be efficiently sensed.

[0067] In at least one embodiment of the present invention, 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 is inserted, as shown in Figure 7, and further comprises an insulating mounting member 720 having a fastening portion 721 on its outer surface so that a power line P is fitted into it.

[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] Figure 7 shows a configuration 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. However, if the shielding case 730 is not used, the first substrate 310 and the second substrate 320 can be mounted by pushing them all the way to the bottom of the mounting member 720. In this case, it is not necessary to form L-shaped grooves 316 at the four corners of the first substrate 310.

[0070] In the examples shown in Figures 8 and 9, a plate-type busbar with a thickness of 2 mm and a width of 10 mm, bent into an L-shape, is used as the power line P. A fastening portion 721 is formed on the side surface of the mounting member 720, and the first substrate 310 and the second substrate 320, which are inserted into the mounting member 720, are attached to the power line P. However, this is merely one embodiment for illustrative purposes, and by forming the fastening portion 721 on the side or bottom surface of the mounting member 720, it can also be applied to straight busbars, annular busbars, or electric wires of a predetermined thickness.

[0071] In at least one embodiment of the present invention, the width of the mounting member 720 may be wider than the width of the power line P, but it is preferable that the widths of each of the coils C1 to C4 constituting the sensor portion 311 be 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. This arrangement is for connecting multiple via holes 312 in a helical coil shape via the track patterning 313. It is also possible to form multiple via holes 312 in two rows in a zigzag pattern or in a straight line, as long as they can be electrically connected in a helical coil shape via the track patterning 313.

[0073] In the example shown in Figure 6, multiple via holes 112 are arranged at a first position in the X direction, and multiple via holes 112 are arranged at a second position in the X direction. The positions of the multiple via holes 112 at the first position in the Y direction are different from the positions of the multiple via holes 112 at the second position in the Y direction, but their respective positions in the Y direction may coincide.

[0074] In other words, when multiple beer holes 312 are formed in two rows aligned in a straight line in the first direction, the number of beer holes in one row may be one more or one less as needed. In any case, the track patterning 313 connects the multiple beer holes 312 with diagonal lines on at least one side, hence the expression "zigzag." As long as they are formed in two rows side by side, the zigzag and straight configurations can be considered the same form.

[0075] In at least one embodiment of the present invention, the line patterning 313 is formed on the conductor layers on both sides of the insulating layer such that a plurality of via holes 312, which are arranged in two rows in the sense described above, are electrically connected in a helical manner, and the first direction is used as the central axis to form coils C1 to C4.

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

[0077] In other words, the current sensor according to at least one embodiment of the present invention can measure the current flowing through a power line without bypassing or cutting the power line, by mounting the sensor so that the first surface of the sensor is adjacent to and close to the power line in its original state.

[0078] In Figures 8 and 9, a plate-shaped busbar is shown as an example of the power line P for which the current is to be measured. However, the current sensor according to at least one embodiment of the present invention can be applied to any shape of power line, including plate-shaped or annular busbars, general-purpose conductors, and the like.

[0079] In at least one embodiment of the present invention, as shown in Figures 4 and 5, the sensor unit 311 includes a plurality of coils C1 to C4 whose central axes are formed substantially parallel to each other, and the plurality of 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 by the induced current induced in coils C1 to C4, so the greater the induced current, the higher the sensitivity. Therefore, sensitivity can be improved by increasing the induced current by connecting multiple coils C1 to C4, whose central axes are formed parallel to each other, in parallel, or by increasing the induced electromotive force by connecting them in series.

[0081] Figure 10 is an exploded perspective view showing the assembly process of a current sensor according to at least one embodiment of the present invention.

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

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

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

[0085] Therefore, when the first substrate 310 on which the sensor portion is formed and the second substrate 320 on which the circuit portion is mounted are physically and electrically connected using a predetermined fastening member (for example, a 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 into the inside of the shielding case 730, and the first substrate 310 is mounted in the shielding case 730 such that both sides protruding in the second direction are fitted into recesses 731 and close the opening 732.

[0086] That is, when the first substrate 310 is fitted into the recess 731 of the shielding case 730, as shown in Figure 10, the surface L1 of the opening 732 of the shielding case 730 and the outer surface L2 of the first substrate 310 become substantially the same plane.

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

[0088] The coils C1 to C4 of the current sensor are mounted in close proximity to the power line through which the current flows. This allows the magnetic field generated by the power line to enter the coil and produce a sinusoidal induced current.

[0089] The filter section functions to allow induced currents to pass through a low-pass filter, passing low-frequency signals and removing high-frequency signals based on a certain frequency. The signal that has passed through the amplifier section then passes through a high-pass filter, where DC component noise is removed and signals below a certain frequency are removed.

[0090] The amplifier section amplifies the signal, which has passed through a low-pass filter, using a differential amplifier (approximately 1000 times) to output a sine wave. The amplification factor can be set as needed.

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

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

[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, as shown in Figure 7, the current sensor 700 is configured, as shown in Figure 8, the plate-shaped power line P is inserted into the rail-shaped groove, and as shown in Figure 9, the current sensor 700 is mounted on the power line P such that the sensor portion is close to the power line P.

[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 to be rotatable outwards, 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, it can be used not only for L-shaped busbars as shown in Figures 8 and 9, but also for straight 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 such that the inner length in a third direction perpendicular to the first and second directions (inner length from the opening to the bottom) is equal to the outer length in the third direction of the shielding case 730 (outer length from the opening to the bottom) (see Figures 7 and 8).

[0099] In this way, a current sensor 700 can be constructed in which the shielding case 730, which includes the sensor and circuit sections, 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 the third direction perpendicular to the first and second directions (inner length from the opening to the bottom) is shorter than the outer length in the third direction of the shielding case 730 (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 if a problem occurs in the fastening portion 721 of the mounting member 720, or in the sensor or circuit portion.

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

[0103] As shown in Figure 11, after mounting the first substrate 310, on which the sensor portion is formed, into the shielding case 730 so as to cover the opening 732, the shielding case 730 is inserted into the mounting member 720 so that the first substrate 310 faces inward, and the first substrate 310 is mounted on the power line P so as to be close to the power line P. When the magnetic flux M generated when current flows through the power line P passes through the coil C of the sensor portion formed on the first substrate 310, an induced current is generated. That is, the coil C of the sensor portion functions as an induction coil that induces the magnetic flux M generated when current flows through the power line P.

[0104] When alternating current flows through a power line P, the magnetic flux M generated around the power line P flows through 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 such an 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 such 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. 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 close the opening 732. Therefore, when the shielding case 730 is attached to the power line P so that the sensor part is close to the power line P, the shielding case 730 shields the outer surface of the sensor part (the side opposite the power line P), and the power line P itself plays the role of shielding the power line P side.

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

[0107] In 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 section is shielded on all four sides. Therefore, the width of the sensor section (length in the first direction) must be set to be less than or equal to the width of the power line P.

[0108] According to the configuration of the present invention described above, 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, thus minimizing the influence of external noise.

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

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

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

[0112] Specifically, Figure 12(b) shows a configuration in which a current sensor is configured using a control board 1210 on which an MCU 1211 is mounted for detecting the current flowing through the power line P and managing power, instead of the circuit board 110 shown in Figure 1.

[0113] Figure 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 with that of a current sensor described in Patent Document 1.

[0114] As shown in Figure 13, in both cases the sensor output increases linearly up to 300A without saturating. However, when we zoom in on the region below 1A, we can see that the current sensor according to at least one embodiment of the present invention still shows a linear increase in sensor output, whereas the current sensor described in Patent Document 1 shows no change in sensor output.

[0115] In other words, the current sensor according to at least one embodiment of the present invention exhibits a linear sensor output not only in terms of the slope of the sensor output with increasing current, but also in terms of low current range of 1A or less, and can be said to have a superior advantage in terms of sensitivity.

[0116] Figure 14 is a measurement graph showing the noise characteristics of a current sensor according to at least one embodiment of the present invention.

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

[0118] Figure 15 is a measurement graph showing the non-saturation characteristics of a current sensor according to at least one embodiment of the present invention.

[0119] The graph in Figure 15 compares the characteristics of a commercial current transformer (CT) with a rated specification of 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 demonstrate an example where a coil is formed using a PCB with multiple via holes and a conductive film on the inner wall, and through line patterning. However, the coil in the sensor part can also be formed using insulated wire.

[0121] Figures 16 and 17 are perspective views showing the coil formation configuration of the sensor portion of a current sensor according to at least one embodiment of the present invention.

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

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

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

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

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

[0127] In the sensor section shown in Figures 16 and 17, the lengths of the lines 1618 and 1718 parallel to the power lines are made as short as possible when forming the line pattern for forming the coil.

[0128] As described above, according to at least one embodiment of the present invention, it is possible to provide a current sensor that minimizes the effects of noise while maintaining high sensitivity when measuring commercial frequency current, 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 or improvements can be made to the above embodiments. It will be clear from the claims that such modified or improved forms may also be included in the technical scope of the present invention. [Explanation of symbols]

[0130] 100, 200, 300, 700: Current sensor 110, 210: Circuit board 120, 220, 311: Sensor section 130, 230, 321: Circuit section 140, 240, 340: Connection part 310: First board 320: Second board 312: Beer hall 313: Track Patterning 314: Sensor output terminal 316: L-shaped groove 317: Conductive film 322: Signal output terminal 323: Power supply terminal 720: Mounting component 730: Shielding case 731: Recess 1200: Control Board 1211:MCU 1610, 1710: Circuit board 1612, 1712: Through hole 1613, 1713: Insulated coated wire C, C1, C2, C3, C4: coil M: Magnetic flux P:Power line

Claims

1. A current sensor for measuring the current flowing through a power line, A sensor portion comprising a substrate including an insulating layer and a first conductor layer and a second conductor layer formed on both sides of the insulating layer, a plurality of via holes having a conductive film on their inner walls formed so as to penetrate the insulating layer and the first and second conductor layers, and a line pattern formed to electrically connect the plurality of via holes to the first and second conductor layers, and a sensor portion comprising at least one helical coil, A circuit section is positioned in close proximity to the sensor section and outputs the detection signal from the sensor section to the outside. A connection section for electrically connecting the sensor section and the circuit section, Equipped with, The width of the sensor portion and the width of the circuit portion in the short direction of the power line, which is perpendicular to the longitudinal direction of the power line in which the current flows, are formed to be less than or equal to the width of the power line that is the object of current measurement, and the circuit portion overlaps with the power line. The sensor unit and the circuit unit are arranged side by side along the longitudinal direction of the power line. Current sensor.

2. A current sensor for measuring the current flowing through a power line, A sensor portion comprising a substrate including an insulating layer and a first conductor layer and a second conductor layer formed on both sides of the insulating layer, a plurality of via holes having a conductive film on their inner walls formed so as to penetrate the insulating layer and the first and second conductor layers, and a line pattern formed to electrically connect the plurality of via holes to the first and second conductor layers, and a sensor portion comprising at least one helical coil, A circuit section is positioned in close proximity to the sensor section and outputs the detection signal from the sensor section to the outside. A connection section for electrically connecting the sensor section and the circuit section, Equipped with, The width of the sensor portion and the width of the circuit portion in the short direction of the power line, which is perpendicular to the longitudinal direction of the power line in which the current flows, are formed to be less than or equal to the width of the power line that is the object of current measurement. The sensor unit and the circuit unit are arranged side by side along the shorter direction of the power line. Current sensor.

3. A current sensor for measuring the current flowing through a power line, A sensor portion comprising a first substrate including an insulating layer and a conductive layer formed on both sides of the insulating layer, a plurality of via holes having a conductive film on their inner walls formed so as to penetrate the insulating layer and the conductive layer, and a line pattern formed in the conductive layer to electrically connect the plurality of via holes, and a sensor portion comprising at least one helical coil, A second board having a circuit section for outputting the detection signal from the sensor section to the outside, A connection section for electrically connecting the sensor section and the circuit section, Equipped with, The width of the sensor portion and the width of the circuit portion in the short direction of the power line, which is perpendicular to the longitudinal direction of the power line in which the current flows, are formed to be less than or equal to the width of the power line that is the object of current measurement, and the circuit portion overlaps with the power line. The first substrate and the second substrate are arranged so as to overlap each other in the direction normal to each other. Current sensor.

4. The coil includes an iron core at its center along the central axis of the coil. The current sensor according to any one of claims 1 to 3.

5. The circuit section includes at least a low-pass filter and an amplifier. The current sensor according to any one of claims 1 to 3.

6. The mounting member is made of an insulating material and is configured in a box shape to house both the sensor unit and the circuit unit inside, and has a fastening portion on its outer surface for fastening the sensor unit to the power line. The current sensor according to any one of claims 1 to 3.

7. To house both the sensor unit and the circuit unit, the device further includes a shielding case made of a conductive material, which is box-shaped and has an opening on the first side. The current sensor according to any one of claims 1 to 3.

8. The mounting member is made of insulating material and is configured in a box shape with one side open so that the opening side of the shielding case can be inserted into it, and has a fastening portion on its outer surface for fastening the sensor part to the power line. The current sensor according to claim 7.

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