Substrate unit and power conversion device

Abstract

To provide a substrate unit capable of suppressing variation in the accuracy of measuring a current flowing through a conductor pattern of the substrate unit.SOLUTION: A substrate unit 11 has a circuit board 20 and a conductor pattern 30 provided on one surface 21 in a thickness direction of the circuit board 20. The substrate unit 11 has: a current detection substrate 40 located on one side UP in the thickness direction with respect to the circuit board 20 and the conductor pattern 30; a non-contact current detection element 50 mounted on one surface 41 of the current detection substrate 40 in the thickness direction at a position overlapping the conductor pattern 30 when the circuit board 20 is viewed in the thickness direction; and a pressing portion 60 that presses the one surface 41 of the current detection substrate 40 in the thickness direction to the other side DW in the thickness direction such that the non-contact current detection element 50 approaches the conductor pattern 30.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This invention relates to a substrate unit having a conductive pattern and a power conversion device having the substrate unit.

Background Art

[0002] Techniques are known for non-contact detection of the current flowing through a conductive pattern of a printed circuit board or a bus bar electrically connected to the printed circuit board using a coreless magnetic sensor IC or the like. Specifically, the magnetic field generated by the current flowing through the conductive pattern is detected by a coreless magnetic sensor IC, and the current flowing through the conductive pattern can be calculated based on the detected magnetic field. For example, Patent Document 1 discloses a circuit board in which a magnetic induction element is disposed on a detection segment of a current trace through which the current of each phase flows when detecting a multi-phase input / output current. In the circuit board of Patent Document 1, the magnetic induction element is disposed such that the internal magnetic field detection direction of the magnetic induction element is parallel to the direction of the magnetic field generated by the current flowing through the detection segment of the current trace. Further, Patent Document 1 discloses fixing the magnetic induction element to the circuit board via an independent printed circuit board.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Disclosure of the Invention

Problems to be Solved by the Invention

[0004] Incidentally, as described in Patent Document 1, when measuring the current flowing through the conductive pattern of the circuit board using a current detection substrate on which a non-contact type current detection element is mounted, the measurement accuracy of the current is determined according to the distance between the current detection element and the conductive pattern. Specifically, when the current detection element is close to the conductive pattern, the measurement accuracy of the current is high, and when the current detection element is away from the conductive pattern, the measurement accuracy of the current decreases. Therefore, in order to accurately measure the current, it is desirable to bring the non-contact type current detection element as close as possible to the conductive pattern. Thus, it is desirable to make the thickness of the current detection substrate as thin as possible.

[0005] However, when the thickness of the current detection substrate becomes thin, the current detection substrate becomes more likely to bend. Therefore, when the thin and bendable current detection substrate is attached to the circuit board, there is a possibility that the contact state between the current detection substrate and the circuit board varies due to the bending of the current detection substrate.

[0006] When the contact state between the current detection substrate and the circuit board varies as described above, the distance between the current detection element and the conductive pattern may vary depending on the portion. The measurement accuracy of the current is locally high at a position where the interval is narrow, while it is low at a position where the interval is wide. For this reason, due to the variation in the contact state, the measurement accuracy of the current may differ depending on the position.

[0007] Therefore, in a configuration for measuring the current flowing through the conductive pattern using a non-contact type current detection element mounted on a current detection substrate, it is desired to suppress the variation in the measurement accuracy of the current.

[0008] An object of the present invention is to provide a substrate unit capable of suppressing variations in the accuracy of measuring the current flowing through the conductive pattern of a circuit board.

Means for Solving the Problems

[0009] The inventors have intensively studied a substrate unit capable of suppressing variations in the accuracy of measuring the current flowing through the conductive pattern of a circuit board. As a result, the inventors have conceived of the following configuration.

[0010] A substrate unit according to an embodiment of the present invention is a unit having a circuit board and a conductive pattern provided on one surface of the circuit board in the thickness direction. The substrate unit includes a current detection substrate positioned on one side in the thickness direction with respect to the circuit board and the conductive pattern, and a non-contact current detection element mounted on one surface of the current detection substrate in the thickness direction at a position overlapping the conductive pattern when the circuit board is viewed in the thickness direction, and capable of detecting the current flowing through the conductive pattern at the position. The substrate unit further includes a pressing portion that presses at least one surface of the non-contact current detection element or the current detection substrate in the thickness direction toward the other side in the thickness direction so that the non-contact current detection element approaches the conductive pattern.

[0011] In the above configuration, the pressing portion can press at least one surface of the non-contact current detection element mounted on the current detection substrate or the current detection substrate itself in the thickness direction toward the other side in the thickness direction. Therefore, even when the thickness of the current detection substrate is thin in order to improve the measurement accuracy of the current, warping of the current detection substrate can be suppressed. Accordingly, the non-contact current detection element can be brought closer to the conductive pattern.

[0012] Therefore, a substrate unit capable of suppressing variations in the accuracy of measuring the current flowing through the conductive pattern of the circuit board can be provided.

[0013] From another perspective, it is preferable that the substrate unit of the present invention includes the following configuration. The substrate unit has a plurality of the conductive patterns and a plurality of the non-contact current detection elements. The current detection substrate is arranged so as to straddle the plurality of conductive patterns. The plurality of non-contact current detection elements are mounted on one surface in the thickness direction of the current detection substrate at positions overlapping with respective ones of the conductive patterns when the circuit board is viewed in the thickness direction.

[0014] Thereby, the current flowing through each of the plurality of conductive patterns can be detected by one current detection substrate. Therefore, the current detection substrate can be miniaturized.

[0015] From another perspective, it is preferable that the substrate unit of the present invention includes the following configuration. Each of the plurality of conductive patterns has a first portion extending in one direction on one surface of the circuit board, a second portion extending in an intersecting direction intersecting the one direction and electrically connected to one end portion of the first portion in the one direction at one end portion in the intersecting direction, and a third portion extending in the one direction and electrically connected to the other end portion of the second portion in the intersecting direction at one end portion in the one direction. Each of the plurality of non-contact current detection elements includes a magnetic sensor. The current detection substrate has a detection region located at a position overlapping with the second portion of the conductive pattern when the circuit board is viewed in the thickness direction. The plurality of non-contact current detection elements including the magnetic sensors are mounted on the detection region of the current detection substrate so as to be able to detect a magnetic field generated by the current flowing through the second portion of the conductive pattern.

[0016] For example, in a configuration where a plurality of conductive patterns extend in one direction and are arranged in parallel in a direction orthogonal to the one direction, the directions in which the current flows are also parallel to each other. Further, when current flows through a plurality of conductive patterns extending in parallel to each other, in each of the plurality of conductive patterns, according to the right-hand screw rule, when viewed in the one direction in which the current flows, a magnetic field is generated in a clockwise or counterclockwise direction around the current path. In the above configuration, when the detection regions of each of the plurality of conductive patterns are located in the orthogonal direction, the magnetic fields generated by the currents flowing through each of the plurality of conductive patterns affect the current detection in each other's detection regions.

[0017] In the above-described configuration, the current detection substrate has a detection region located at a position overlapping with the second portion of the conductive pattern when viewed in the thickness direction of the circuit board.

[0018] Since the second portion extends intersecting the first portion and the third portion of the conductive pattern, in the second portion, it does not receive a magnetic field in a direction that interferes with the magnetic sensor from other conductive patterns. Therefore, the accuracy of current detection by the non-contact current detection element is improved.

[0019] From another viewpoint, it is preferable that the substrate unit of the present invention includes the following configuration. It further has a magnetic shield made of a magnetic material. The non-contact current detection element includes a magnetic sensor. The magnetic shield is located at a position overlapping with each of the non-contact current detection element and the conductive pattern when viewed in the thickness direction of the circuit board, and has a shape surrounding at least a part of the periphery of the conductive pattern and the non-contact current detection element when viewed in the direction in which the conductive pattern extends.

[0020] Thereby, a magnetic field that interferes with the magnetic sensor can be blocked by the magnetic shield made of a magnetic material. Therefore, the accuracy of current detection by the non-contact current detection element is improved.

[0021] The power conversion device according to an embodiment of the present invention includes the substrate unit. A power conversion circuit is formed on the circuit board included in the substrate unit.

[0022] According to the above configuration, the current of the power conversion circuit can be accurately detected.

[0023] The technical terms used in this specification are used for the purpose of defining only specific embodiments, and are not intended to limit the invention by said technical terms.

[0024] As used herein, "and / or" includes all combinations of one or more of the associated listed components.

[0025] As used herein, the use of "including", "comprising", or "having" and their variations identifies the presence of the described features, steps, operations, elements, components, and / or their equivalents, but may include one or more of steps, actions, elements, components, and / or their groups.

[0026] As used herein, "attached", "connected", "coupled", and / or their equivalents are used in a broad sense and include both "direct and indirect" attachment, connection, and coupling. Further, "connected" and "coupled" are not limited to physical or mechanical connections or couplings, and may include direct or indirect electrical connections or couplings.

[0027] Unless otherwise defined, all terms (including technical and scientific terms) used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0028] Terms defined in commonly used dictionaries should be interpreted to have meanings consistent with their meanings in the context of the relevant art and this disclosure, and should not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0029] In the description of the present invention, it is understood that several techniques and processes are disclosed. Each of these has individual benefits and can also be used together with one or more, or in some cases all, of the other disclosed techniques.

[0030] Therefore, for clarity, the description of the present invention refrains from repeating all possible combinations of the individual steps unnecessarily. However, this specification and the claims should be read with the understanding that all such combinations are within the scope of the present invention.

[0031] This specification describes embodiments of a substrate unit according to the present invention.

[0032] In the following description, numerous specific examples are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention can be practiced without these specific examples.

[0033] Thus, the following disclosure should be considered as illustrative of the present invention and is not intended to limit the present invention to the specific embodiments shown in the following drawings or description.

[0034] [Power conversion device] In this specification, a power conversion device is a device that converts and outputs input power. The power conversion device has a power conversion circuit that converts the input power. The power conversion circuit has, for example, a plurality of switching elements. The switching elements are driven and controlled by a control circuit formed on a control substrate. The power conversion circuit may be a circuit having components other than the switching elements as long as it has a configuration capable of converting power.

[0035] [Circuit board] In this specification, a circuit board is a board on which a conductor pattern is provided and electronic components are mounted. The circuit board is, for example, a board on which components for performing power conversion in a power conversion device are mounted. A power conversion circuit is formed on the circuit board. A control circuit may be formed on the circuit board. The control circuit may be formed on the circuit board or on a board separate from the circuit board.

[0036] [Conductor pattern] In this specification, a conductor pattern means the wiring of conductors formed on a circuit board. The conductor pattern constitutes an electronic circuit by being connected to electronic components mounted on the circuit board. The conductor pattern can be constituted by a conductor such as copper.

[0037] [Power conversion circuit] In this specification, a power conversion circuit means a circuit that converts and outputs input power. The power conversion circuit includes, for example, switching elements driven and controlled by a control circuit.

[0038] [Non-contact current detection element] In this specification, a non-contact current detection element means a current detection element that can detect the current flowing through the conductor pattern in a non-contact state with the conductor pattern. Examples of the non-contact current detection element include coreless magnetic sensors.

[0039] [Span across] In this specification, when a current detection board spans across a conductor pattern, it means that the current detection board extends above the conductor pattern in a direction intersecting the extending direction of the conductor pattern from one side to the other side of the conductor pattern.

[0040] [Magnetic sensor] In this specification, a magnetic sensor means a sensor that detects the magnitude and direction of a magnetic field generated by an electric current. The magnetic sensor may include, for example, a Hall element that detects a magnetic field by the Hall effect.

Advantages of the Invention

[0041] According to an embodiment of the present invention, it is possible to provide a substrate unit that can suppress variations in the accuracy of measuring the current flowing through the conductive pattern of a circuit board.

Brief Description of the Drawings

[0042]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Modes for Carrying Out the Invention

[0043] Hereinafter, embodiments will be described with reference to the drawings. In each figure, the same reference numerals are assigned to the same parts, and the description of the same parts will not be repeated. Note that the dimensions of the components in each figure do not faithfully represent the actual dimensions of the components and the dimensional ratios of the components.

[0044] Hereinafter, the arrow FR in the figure indicates one of the depth directions of the substrate units 11, 12, 13, 14, the circuit board 20, and the current detection boards 40, 400. The arrow RR in the figure indicates the other of the depth directions of the substrate units 11, 12, 13, 14, the circuit board 20, and the current detection boards 40, 400. The arrow LF in the figure indicates one of the width directions of the substrate units 11, 12, 13, 14, the circuit board 20, and the current detection boards 40, 400. The arrow RG in the figure indicates the other of the width directions of the substrate units 11, 12, 13, 14, the circuit board 20, and the current detection boards 40, 400. The depth direction and the width direction are orthogonal. The arrow UP in the figure indicates one of the thickness directions of the substrate units 11, 12, 13, 14, the circuit board 20, and the current detection boards 40, 400. The arrow DW in the figure indicates the other of the thickness directions of the substrate units 11, 12, 13, 14, the circuit board 20, and the current detection boards 40, 400. The thickness direction is orthogonal to the depth direction and the width direction.

[0045] [Embodiment 1] (Schematic Configuration) FIG. 1 is a plan view showing a schematic configuration of a substrate unit 11 according to Embodiment 1. FIG. 2 is a cross-sectional view taken along line II-II shown in FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III shown in FIG. 1.

[0046] As shown in FIGS. 1 to 3, the substrate unit 11 includes a circuit board 20, a conductive pattern 30, a current detection board 40, a non-contact current detection element 50, and a pressing portion 60.

[0047] The circuit board 20 is a plate-shaped base material that supports electronic components. The circuit board 20 may be a rigid board or a flexible board. The circuit board 20 may be configured, for example, by impregnating a paper base material or a glass base material with resin. The circuit board 20 can be composed of a resin plate, a resin film, or a metal plate such as aluminum.

[0048] The conductive pattern 30 is a conductor wiring formed on one surface 21 in the thickness direction of the circuit board 20. The conductive pattern 30 can be composed of a conductor such as a copper foil. The conductive pattern 30 has a first terminal 31, a detected portion 32, and a second terminal 33. The first terminal 31 and the second terminal 33 are connected to a power source (not shown), and current is supplied from the power source. The detected portion 32 connects the first terminal 31 and the second terminal 33. For example, as shown by the arrow in FIG. 1, current flows from the first terminal 31, through the detected portion 32, to the second terminal 33.

[0049] The current detection board 40 is a plate-shaped base material on which the non-contact current detection element 50 is mounted. The circuit board 20 may be a rigid board or a flexible board. The circuit board 20 may be configured, for example, by impregnating a paper base material or a glass base material with resin. The circuit board 20 can be composed of a member that transmits magnetic flux lines, such as a resin plate or a resin film. The current detection board 40 is located on one side UP in the thickness direction with respect to the circuit board 20 and the conductive pattern 30. As shown in FIG. 1, the current detection board 40 has an output terminal 45 that outputs an electric current signal output by the non-contact current detection element 50 to the outside, and a conductive pattern 42 that electrically connects the output terminal 45 and the non-contact current detection element 50.

[0050] The non-contact current detection element 50 is a current detection element that can detect the current flowing through the conductor pattern 30 in a non-contact state with the conductor pattern 30. The non-contact current detection element 50 has a magnetic sensor 51 for detecting a magnetic field. The magnetic sensor 51 can be constituted by a coreless magnetic sensor IC or the like. The non-contact current detection element 50 detects the magnetic field generated by the current flowing through the current path to be detected by the magnetic sensor 51, and calculates the current value based on the detected magnetic field. The non-contact current detection element 50 generates and outputs a current signal based on the calculated current value. The non-contact current detection element 50 is mounted on one surface 41 in the thickness direction of the current detection substrate 40 at a position overlapping the detected portion 32 of the conductor pattern 30 when viewed in the thickness direction of the circuit board 20. The non-contact current detection element 50 detects the current flowing through the conductor pattern 30 at the above position. Specifically, when a current flows from the first terminal 31 through the detected portion 32 to the second terminal 33 below the non-contact current detection element 50, according to the right-hand screw rule, as shown by the dashed arrow in FIG. 2, a magnetic field is generated in the counterclockwise direction with respect to the current path P1 of the current when viewed in the depth direction in which the current flows. The non-contact current detection element 50 outputs a current signal in response to the magnetic field generated along with the current flowing through the detected portion 32 of the conductor pattern 30. The current signal output by the non-contact current detection element 50 is output to the outside from the output terminal 45 via the conductor pattern 42.

[0051] The pressing portion 60 is a member that presses the current detection substrate 40 in the other direction DW in the thickness direction. The pressing portion 60 presses one surface 41 in the thickness direction of the current detection substrate 40 in the other direction DW in the thickness direction so that the non-contact current detection element 50 approaches the detected portion 32 of the conductor pattern 30.

[0052] As shown in FIG. 1, one side LF and the other side RG in the width direction of the current detection substrate 40 and the pressing portion 60 are fixed to the circuit board 20 by fixing portions 61, 62. The fixing portions 61, 62 can be constituted by, for example, screws or pins.

[0053] In the above configuration, as shown by the white arrows in FIGS. 2 and 3, the pressing portion 60 can press one surface 41 of the current detection substrate 40 in the thickness direction toward the other direction DW in the thickness direction. Therefore, even when the thickness of the current detection substrate 40 is thin in order to improve the measurement accuracy of the current, the warping of the current detection substrate 40 can be suppressed. Accordingly, the non-contact current detection element 50 can be brought closer to the detection portion 32 of the conductive pattern 30.

[0054] From the above, it is possible to provide the substrate unit 11 that can suppress variations in the accuracy of measuring the current flowing through the conductive pattern 30 of the circuit board 20.

[0055] Further, the pressing portion 60 is configured such that a space SP1 is formed above the non-contact current detection element 50. For this reason, the pressing portion 60 does not directly contact the upper surface of the non-contact current detection element 50. Therefore, it is possible to prevent unintentional pressure or vibration from being applied to the non-contact current detection element 50.

[0056] [Embodiment 2] (Schematic Configuration) FIG. 4 is a plan view showing a schematic configuration of a power conversion device 70 equipped with a substrate unit 12 according to Embodiment 2. FIG. 5 is an enlarged perspective view of a range V shown in FIG. 4. FIG. 6 is a cross-sectional view taken along line VI-VI shown in FIG. 5. FIG. 7 is an exploded perspective view of a part of the substrate unit 12 shown in FIG. 5. The substrate unit 12 according to Embodiment 2 is mounted on the power conversion device 70. Further, the substrate unit 12 detects the current values of three-phase alternating current of the U-phase, V-phase, and W-phase flowing through an output portion connected to an external load 75. For this reason, the substrate unit 12 is different from the substrate unit 11 according to Embodiment 1 in that it has a plurality of conductive patterns. In the following description of Embodiment 2, parts common to the substrate unit 11 according to Embodiment 1 are denoted by the same reference numerals and detailed description thereof will not be repeated.

[0057] The power conversion device 70 is a device that converts input power and outputs it. The power conversion device 70 has a substrate unit 12 in which a power conversion circuit for converting input power is formed.

[0058] The substrate unit 12 is, for example, a plate-shaped substrate having a circuit that converts and outputs the input power. For example, a power conversion circuit having switching elements is formed on the substrate unit 12. The substrate unit 12 converts the DC power supplied from a power source 73 such as a battery into AC power in response to the drive control of the switching elements by a control circuit (not shown), and outputs it to an external load 75. The external load 75 is, for example, a motor or the like. The control circuit may be included in the substrate unit 12 or may be included in a control board separate from the substrate unit 12.

[0059] As shown in FIGS. 4 to 8, the substrate unit 12 includes a circuit board 20, a U-phase conductor pattern U30, a V-phase conductor pattern V30, a W-phase conductor pattern W30, an upper arm switching unit 71, a lower arm switching unit 72, a first power supply terminal 741, a second power supply terminal 742, a current detection board 400, non-contact current detection elements U50, V50, W50, and a pressing unit 600.

[0060] The U-phase conductor pattern U30, the V-phase conductor pattern V30, the W-phase conductor pattern W30, the upper arm switching unit 71, the lower arm switching unit 72, the first power supply terminal 741, and the second power supply terminal 742 constitute the power conversion circuit.

[0061] The upper arm switching unit 71 and the lower arm switching unit 72 have a plurality of switching elements. The upper arm switching unit 71 drives the plurality of switching elements in response to the control signal of the control circuit, so that the output currents of the three-phase AC of the U-phase, V-phase, and W-phase flow through the U-phase conductor pattern U30, the V-phase conductor pattern V30, and the W-phase conductor pattern W30. As the driving method of the plurality of switching elements, a conventional technique can be adopted.

[0062] The U-phase conductor pattern U30, the V-phase conductor pattern V30, and the W-phase conductor pattern W30 constitute an output section connected to the external load 75. That is, the U-phase output current flows through the U-phase conductor pattern U30. The V-phase output current flows through the V-phase conductor pattern V30. The W-phase output current flows through the W-phase conductor pattern W30. The U-phase conductor pattern U30, the V-phase conductor pattern V30, and the W-phase conductor pattern W30 each have a first portion 301, a second portion 302, and a third portion 303.

[0063] The current detection substrate 400 is arranged so as to straddle the U-phase conductor pattern U30, the V-phase conductor pattern V30, and the W-phase conductor pattern W30 as a plurality of conductor patterns. The current detection substrate 400 extends in the width direction so as to intersect the U-phase conductor pattern U30, the V-phase conductor pattern V30, and the W-phase conductor pattern W30. A plurality of non-contact current detection elements U50, V50, and W50 as non-contact current detection elements are mounted on one surface 41 of the current detection substrate 400. The non-contact current detection elements U50, V50, and W50 are mounted at positions overlapping the U-phase conductor pattern U30, the V-phase conductor pattern V30, and the W-phase conductor pattern W30, respectively, when viewed in the thickness direction of the circuit board 20.

[0064] Thereby, the current flowing through each of the plurality of conductor patterns of the U-phase conductor pattern U30, the V-phase conductor pattern V30, and the W-phase conductor pattern W30 can be detected by one current detection substrate 400. Therefore, the current detection substrate 400 can be miniaturized.

[0065] As shown in FIG. 7, the output terminals 41 of the current detection substrate 400 are electrically connected to the non-contact current detection elements U50, V50, and W50, respectively, by the conductor pattern 42. The method of current detection in the current detection substrate 400 will be described later.

[0066] As shown in FIG. 7, the pressing portion 600 presses the pressing region R60 on one surface 41 in the thickness direction of the current detection substrate 40 in the other direction DW in the thickness direction. The pressing region R60 indicated by hatching in FIG. 7 may be located, for example, between the non-contact current detection element U50 and the non-contact current detection element V50 and between the non-contact current detection element V50 and the non-contact current detection element W50.

[0067] (Current Detection in Current Detection Substrate) Among the three phases of U-phase, V-phase, and W-phase, the configuration of current detection of the V-phase will be typically described. As shown in FIGS. 6 and 7, between the first portion 301 and the second portion 302 of the V-phase conductor pattern V30, a slit 306 extending from one edge 304 in the width direction LG of the V-phase conductor pattern V30 to the other width direction RG is provided. Between the second portion 302 and the third portion 303 of the V-phase conductor pattern V30, a slit 307 extending from the other edge 305 in the width direction RG of the V-phase conductor pattern V30 to the one width direction LG is provided.

[0068] In the above configuration, the first portion 301 extends in the depth direction (one direction) on one surface 21 of the circuit board 20.

[0069] The second portion 302 extends in the width direction (intersecting direction) intersecting the depth direction and is electrically connected to one end in the depth direction of the first portion 301 at one end in the width direction.

[0070] The third portion 303 is electrically connected to the other end in the width direction of the second portion 302 at one end in the depth direction and extends in the depth direction.

[0071] Therefore, when current flows from the first portion 301, through the second portion 302, to the third portion 303, as indicated by the arrow in FIG. 7, the current flows from the first portion 301 to the second portion 302 in the direction of the other side RR in the depth direction, in the second portion 302, it flows in the direction of one side LG in the width direction, and from the second portion 302 to the third portion 303, it flows in the direction of the other side RR in the depth direction. Therefore, when current flows from the first portion 301, through the second portion 302, to the third portion 303, according to the right-hand screw rule, in the second portion 302, as shown by the dashed arrow in FIG. 6, a magnetic field is generated in the counterclockwise direction with respect to the current path P1 when viewed in the width direction in which the current flows.

[0072] As shown in FIGS. 6 and 7, the current detection substrate 400 has a detection region R40, which is a position for detecting the V-phase current, at a position overlapping with the second portion 302 of the V-phase conductor pattern (conductor pattern) V30 when viewed in the thickness direction of the circuit board 20. The non-contact current detection element V50 including a magnetic sensor is mounted on the detection region R40 of the current detection substrate 400 so as to be able to detect the magnetic field generated by the current flowing through the second portion 302 of the V-phase conductor pattern V30. The non-contact current detection element V50 outputs a current signal based on the magnetic field generated along with the current flowing through the second portion 302. Note that the configurations for detecting the U-phase and W-phase currents are the same as the above-described V-phase configuration.

[0073] According to the above configuration, the detection regions R40 for the U-phase current, the V-phase current, and the W-phase current are located at positions overlapping with the second portions 302 of the U-phase conductor pattern U30, the V-phase conductor pattern V30, and the W-phase conductor pattern W30, respectively. Thereby, it is possible to avoid the detection regions R40 for the U-phase current, the V-phase current, and the W-phase current from being arranged in the direction in which a magnetic field is generated in the second portion. For this reason, in the detection regions R40 for the U-phase current, the V-phase current, and the W-phase current, it is possible to suppress the generation of a magnetic field that interferes with each other in the current detection by the magnetic sensors of the non-contact current detection elements U50, V50, and W50. Therefore, the accuracy of current detection by the non-contact current detection elements U50, V50, and W50 is improved.

[0074] In the above-described configuration, a power conversion circuit is formed on the circuit board 20 of the substrate unit 12. Therefore, the current of the power conversion circuit can be accurately detected.

[0075] [Embodiment 3] (Schematic Configuration) FIG. 8 is a perspective view showing a part of a power conversion device 70 equipped with a substrate unit 13 according to Embodiment 3. FIG. 9 is an exploded perspective view of the substrate unit 13 shown in FIG. 8. The substrate unit 13 according to Embodiment 3 is different from the substrate unit 12 according to Embodiment 2 in that the pressing portion 620 presses the pressing region R61 on one surface UP in the thickness direction of the non-contact current detection elements U50, V50, W50 toward the other surface DW in the thickness direction. In the following description of Embodiment 3, parts common to the substrate unit 12 according to Embodiment 2 are denoted by the same reference numerals and detailed description will not be repeated.

[0076] As shown in FIGS. 8 and 9, the substrate unit 13 includes a circuit board 20, a U-phase conductor pattern U30, a V-phase conductor pattern V30, a W-phase conductor pattern W30, an upper arm switching portion 71, a current detection board 400, non-contact current detection elements U50, V50, W50, and a pressing portion 620. Although not shown in FIGS. 8 and 9, the substrate unit 13 has a lower arm switching portion 72, a first power supply terminal 741, and a second power supply terminal 742, similar to the substrate unit 12 according to the above-described Embodiment 2.

[0077] The pressing portion 620 has a pressing protrusion 621. The pressing protrusion 621 protrudes from the upper portion in the thickness direction of the pressing portion 620 toward the other side DW in the thickness direction. The pressing protrusion 621 is located at a position overlapping the non-contact current detection elements U50, V50, and W50 when viewed in the thickness direction. Therefore, the pressing portion 620 presses the pressing region R61 on the surface of the non-contact current detection elements U50, V50, and W50 on one side UP in the thickness direction toward the other side DW in the thickness direction by the pressing protrusion 621. Since the pressing protrusion 621 presses the pressing region R61 indicated by the hatching in FIG. 9 toward the other side DW in the thickness direction, the non-contact current detection elements U50, V50, and W50 can be brought closer to the U-phase conductor pattern U30, the V-phase conductor pattern V30, and the W-phase conductor pattern W30.

[0078] [Embodiment 4] (Schematic Configuration) FIG. 10 is a plan view showing a part of the schematic configuration of the substrate unit 14 according to Embodiment 4. FIG. 11 is a cross-sectional view taken along line XI-XI shown in FIG. 10. The substrate unit 14 according to Embodiment 4 is different from the substrate unit 11 according to Embodiment 1 in that it has a magnetic shield 77. In the following description of Embodiment 4, the same reference numerals are given to the parts common to the substrate unit 11 according to Embodiment 1, and detailed descriptions thereof will not be repeated.

[0079] As shown in FIGS. 10 and 11, the substrate unit 14 includes a circuit board 20, a conductor pattern 30, a current detection board 40, a non-contact current detection element 50, a pressing portion 60, and a magnetic shield 77.

[0080] The magnetic shield 77 is made of a magnetic material such as ferrosilicon (FeSi). The magnetic shield 77 is located at a position overlapping each of the non-contact current detection element 50 and the detected portion 32 of the conductor pattern 30 when the circuit board 20 is viewed in the thickness direction. The magnetic shield 77 has a shape surrounding at least a part of the periphery of the conductor pattern 30 and the non-contact current detection element 50 when viewed in the direction in which the conductor pattern 30 extends. More specifically, as shown in FIG. 11, the magnetic shield 77 includes a first side wall portion 771, a second side wall portion 772, and a connecting portion 773.

[0081] The first side wall portion 771 is located on one side LF in the width direction of the conductive pattern 30 and the non-contact current detection element 50. The first side wall portion 771 penetrates the circuit board 20 in the thickness direction and extends in the thickness direction.

[0082] The second side wall portion 772 is located on the other side RG in the width direction of the conductive pattern 30 and the non-contact current detection element 50. The second side wall portion 772 penetrates the circuit board 20 in the thickness direction and extends in the thickness direction.

[0083] The connecting portion 773 is located on the other side DW in the thickness direction of the circuit board 20 and extends in the width direction. The connecting portion 773 is connected to the lower end portion of the first side wall portion 771 at the end on one side LF in the width direction, and is connected to the lower end of the second side wall portion 772 at the end on the other side RG in the width direction.

[0084] The magnetic shield 77 can block a magnetic field that interferes with the magnetic sensor 51 of the non-contact current detection element 50. Therefore, the accuracy of current detection by the non-contact current detection element 50 is improved.

[0085] [Other Embodiments] The embodiments of the present invention have been described above, but the above-described embodiments are merely examples for implementing the present invention. Therefore, the present invention is not limited to the above-described embodiments, and the above-described embodiments can be appropriately modified and implemented without departing from the spirit thereof.

[0086] In each of the above embodiments, although not particularly described, the power conversion device 70 is attached to an attachment target such as a moving body, for example. However, the power conversion device may be attached to other devices or structures, etc., or may be used alone without being attached to other devices or structures, etc.

[0087] In each of the above embodiments, one side LF and the other side RG in the width direction of the current detection substrates 40 and 400 and the pressing portions 60, 600, and 620 are supported and fixed to the circuit board 20 by fixing portions 61 and 62 such as screws or pins. However, the method of fixing the current detection substrate and the pressing portion to the circuit board is not limited to this. An engaging portion may be provided on either the current detection substrate and the pressing portion or the circuit board, and an engaged portion may be provided on the other, so that the current detection substrate and the pressing portion and the circuit board may be fixed. Further, the current detection substrate and the pressing portion may be separately fixed to the circuit board.

[0088] In Embodiments 1, 2, and 4, the pressing portions 60 and 600 press one surface 41 in the thickness direction of the current detection substrates 40 and 400 in the other direction DW in the thickness direction. Further, in Embodiment 3, the pressing portion 620 presses the pressing region R61 on one surface UP in the thickness direction of each of the non-contact current detection elements U50, V50, and W50 in the other direction DW in the thickness direction. However, the pressing portion may press both the current detection substrate and the non-contact current detection element.

[0089] In Embodiment 3, the pressing portion 620 presses the non-contact current detection elements U50, V50, and W50. However, each of the plurality of non-contact current detection elements may be separately pressed by a respective pressing portion.

[0090] In Embodiments 2 and 3, the current detection substrate 400 detects the current value flowing through the output portion connected to the external load 75. However, the current detection substrate may be used to detect the current value of another portion. For example, the current detection substrate may detect the current value flowing through the input portion of the power supply.

[0091] In Embodiments 2 and 3, the current detection substrate 400 detects the current values flowing through the U-phase conductor pattern U30, the V-phase conductor pattern V30, and the W-phase conductor pattern W30. However, each of the current values of the U-phase conductor pattern, the V-phase conductor pattern, and the W-phase conductor pattern may be detected by separate current detection substrates. Further, a plurality of current detection substrates may be pressed by one pressing portion or may be pressed by a plurality of pressing portions.

[0092] In the second embodiment, the second portion 302 is orthogonal to the first portion 301 and the third portion 303. However, the second portion may be connected to intersect with the first portion and the third portion.

[0093] In the fourth embodiment, the magnetic shield 77 has a shape that surrounds at least a part of the periphery of the conductor pattern 30 and the non-contact current detection element 50 when viewed in the direction in which the conductor pattern 30 extends. Also, the first side wall portion 771 of the magnetic shield 77 and the second side wall portion 772 are connected by a connecting portion 773. However, the magnetic shield may have a shape that surrounds the entire circumference of the conductor pattern and the non-contact current detection element. Also, the first side wall portion and the second side wall portion of the magnetic shield may not be connected. Also, the first side wall portion and the second side wall portion may extend in a direction different from the thickness direction. For example, the first side wall portion and the second side wall portion may extend in the width direction.

Description of Reference Numerals

[0094] 11, 12, 13, 14 Substrate unit 20 Circuit board 21 One surface 30 Conductor pattern 31 First terminal 32 Portion to be detected 33 Second terminal 301 First portion 302 Second portion 303 Third portion 304, 305 Edge 306, 307 Slit 40, 400 Current detection substrate 41 One surface 42 Conductor pattern 45 Output terminal 50 Non-contact current detection element 51 Magnetic sensor 60, 600, 620 Pressing portion 61, 62 Fixing portion 621 Pressing projection 70 Power conversion device 71 Upper arm switching section 72 Lower arm switching section 73 Power supply 741 First power supply terminal 742 Second power supply terminal 75 External load 77 Magnetic shield 771 First side wall portion 772 Second side wall portion 773 Connecting portion P1 Current path R40 Detection region R60, R61 Pressing region SP1 Space U30 U-phase conductor pattern U50 Non-contact current detection element V30 V-phase conductor pattern V50 Non-contact current detection element W30 W-phase conductor pattern W50 Non-contact current detection element

Claims

1. A substrate unit having a circuit board and a conductive pattern provided on one surface of the circuit board in the thickness direction, a current detection substrate located on one side in the thickness direction with respect to the circuit board and the conductive pattern, a non-contact current detection element mounted on one surface of the current detection substrate in the thickness direction at a position overlapping the conductive pattern when viewed in the thickness direction of the circuit board, and capable of detecting the current flowing through the conductive pattern at the position, a pressing portion that presses at least one of the non-contact current detection element or the current detection substrate on one surface in the thickness direction toward the other side in the thickness direction so that the non-contact current detection element approaches the conductive pattern, and having, a substrate unit.

2. In the substrate unit according to Claim 1, the substrate unit has, a plurality of the conductive patterns, a plurality of the non-contact current detection elements, and having, the current detection substrate is arranged so as to straddle the plurality of conductive patterns, the plurality of non-contact current detection elements are mounted on one surface of the current detection substrate in the thickness direction at positions overlapping the respective conductive patterns when viewed in the thickness direction of the circuit board, a substrate unit.

3. In the substrate unit according to Claim 1 or Claim 2, each of the plurality of conductive patterns has, on the one surface of the circuit board, a first portion extending in one direction, a second portion extending in an intersecting direction intersecting the one direction and electrically connected to one end portion of the first portion in the one direction at one end portion in the intersecting direction, and a third portion extending in the one direction and electrically connected to the other end portion of the second portion in the intersecting direction at one end portion in the one direction, each of the plurality of non-contact current detection elements includes a magnetic sensor, the current detection substrate has a detection region located at a position overlapping the second portion of the conductive pattern when viewed in the thickness direction of the circuit board, the plurality of non-contact current detection elements including the magnetic sensor are mounted on the detection region of the current detection substrate so as to be able to detect a magnetic field generated by the current flowing through the second portion of the conductive pattern, a substrate unit.

4. In the substrate unit according to any one of Claims 1 to 3, further having a magnetic shield made of a magnetic material, the non-contact current detection element includes a magnetic sensor, The magnetic shield is positioned at a position overlapping each of the non-contact current detection element and the conductor pattern when viewing the circuit board in the thickness direction, and has a shape surrounding at least a part of the periphery of the conductor pattern and the non-contact current detection element when viewing in the direction in which the conductor pattern extends, a substrate unit. **Claim 5** A power conversion device having the substrate unit according to any one of Claims 1 to 4, wherein a power conversion circuit is formed on the circuit board included in the substrate unit, a power conversion device.

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