Electronic device

Abstract

To provide an electronic device capable of preventing occurrence of crosstalk caused by mutual coupling with a magnetic field generated around electric paths that make up a circuit, thereby improving current detection accuracy.SOLUTION: An electronic device 1 includes a current sensor 7 that is located opposite a bus bar 30, which is used as an electrical path constituting a circuit, and detects a current flowing through the bus bar 30 based on a magnetic field generated around the bus bar 30. The bus bar 30 has a first extension portion 31 extending in a first direction and a second extension portion 32 extending in a second direction different from the first direction and including a sensor area SA opposite to the current sensor 7.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to electronic devices. [Background technology]

[0002] Patent Document 1 describes an electronic device (power conversion device) in which a sensor unit that functions as an output terminal block holds multiple bus bars, and a coreless current detection sensor is placed inside the housing of the sensor unit in a position facing the bus bars. Such a non-contact current sensor can detect the current flowing through the bus bars based on the magnetic field that is generated around the bus bars when a current is passed through them. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-164244 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when an electric circuit formed by bus bars and the like extends linearly as in Patent Document 1, the magnetic field generated in the electric circuit by the passage of current is a concentric magnetic field centered on the electric circuit. Therefore, when other bus bars or wiring (signal lines) are arranged parallel to the electric circuit near the electric circuit, the magnetic fields generated around these bus bars or wiring are likely to be mutually coupled, causing crosstalk and potentially reducing the accuracy of current detection.

[0005] In consideration of the above, the present invention aims to provide an electronic device that can suppress the occurrence of crosstalk due to mutual coupling with magnetic fields generated around the electrical paths that make up the circuit, thereby improving the accuracy of current detection.

[0006] An electronic device according to a first aspect of the present invention is an electronic device comprising a current sensor arranged opposite an electric path that constitutes a circuit and that detects a current flowing in the electric path based on a magnetic field generated around the electric path, wherein the electric path has a first extension portion extending along a first direction and a second extension portion extending along a second direction different from the first direction and including a sensor area that faces the current sensor. [Effects of the Invention]

[0007] According to a first aspect of the present invention, the electronic device includes a current sensor disposed opposite an electric path constituting a circuit. The current sensor is configured to detect a current flowing through the electric path based on a magnetic field generated around the electric path. The electric path includes a first extension extending along a first direction and a second extension extending along a second direction different from the first direction, and a sensor region facing the current sensor is formed on the second extension. Therefore, the direction of the magnetic field generated around the electric path changes in the second extension where the sensor region is provided, to a direction different from that of the first extension. This reduces mutual coupling between the sensor region of the second extension and magnetic fields generated by surrounding bus bars, wiring, etc. arranged parallel to the first extension, thereby suppressing crosstalk. As a result, the current detection accuracy can be improved. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing a circuit configuration of an electronic device according to a first embodiment. [Figure 2] 1 is a plan view of the inside of a housing of an electronic device according to a first embodiment, viewed from above. [Figure 3] FIG. 3 is a partial cross-sectional view of the electronic device taken along line III-III in FIG. 2. [Figure 4] 3 is an enlarged plan view of the front part of the housing according to the first embodiment, viewed from above. FIG. [Figure 5] 1A is a partially enlarged plan view of a bus bar that constitutes an electrical path, and FIG. 1B is a partially enlarged side view of the bus bar. [Figure 6]FIG. 10 is an exploded perspective view of an electronic device according to a second embodiment. [Figure 7] FIG. 10 is a plan view of a substrate according to a second embodiment, viewed from above. [Figure 8] FIG. 10 is a partially enlarged side view of a substrate according to a second embodiment, showing terminal members and wiring patterns that form electrical paths. [Figure 9] 9A is a cross-sectional view taken along line 9A-9A in FIG. 8, and FIG. 9B is a cross-sectional view taken along line 9B-9B in FIG. [Figure 10] 5(B) is an enlarged side view showing a modification of the bus bar according to the first embodiment and corresponding to FIG. 5(B). [Figure 11] FIG. 10 is a diagram showing a modified example of the circuit configuration of the electronic device according to the first and second embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0009] First Embodiment An electronic device 1 according to a first embodiment of the present invention will be described below with reference to Figures 1 to 5. In the first embodiment, for convenience of explanation, the directions indicated by the up / down, left / right, and front / rear arrows shown appropriately in each figure will be defined as the up / down direction, left / right direction, and front / rear direction of the power control device, respectively.

[0010] Unless otherwise specified in the specification, each element is not limited to one, and may be present in plural. Furthermore, in the drawings, substantially identical elements are denoted by the same reference numerals, and redundant explanations in the specification will be omitted.

[0011] (Circuit configuration of electronic devices) FIG. 1 is a circuit diagram showing the circuit configuration of the electronic device 1. As an example, the electronic device 1 constitutes a power control device that controls the supply of power between a battery 2 (power source) and a three-phase AC motor 4 (power supply target) mounted on a vehicle. The three-phase AC motor 4 is used, for example, as a drive source for the vehicle. As an example of power control, the electronic device 1 converts DC voltage from the battery 2 into three-phase AC voltage for the three-phase AC motor 4. This allows the three-phase AC motor 4 to rotate with the power charged in the battery. The electronic device 1 includes, as its circuit configuration, a capacitor 3, an inverter circuit 5, a control unit 6, and a current sensor 7. These circuit elements are electrically connected by wiring 52 as an electrical path and a bus bar 30, which will be described later. Note that the circuit configuration of the electronic device 1 is not limited to this, and modifications and additions to the configuration are possible as appropriate.

[0012] The capacitor 3 is connected between a first wiring 52P connected to the positive electrode of the battery 2 and a second wiring 52N connected to the negative electrode of the battery 2. The capacitor 3 is connected in parallel to the battery 2, and functions as a filter that removes noise from the DC voltage supplied from the battery 2 to an inverter circuit 5, which will be described later.

[0013] The inverter circuit 5 is a conversion circuit that converts DC voltage supplied from the battery 2 into AC voltage and supplies it to each phase of the three-phase AC motor 4. The inverter circuit 5 is composed of a switching circuit with multiple switching elements 54. The inverter circuit 5 has three upper and lower arms corresponding to the U, V, and W phases of the three-phase AC motor 4. Each upper arm is composed of multiple switching elements 54 (54UH, 54VH, 54WH) connected to a first wiring 52P on the high-voltage side (high side) that connects the positive electrode of the battery 2 and the three-phase AC motor. The three upper arms form a high-side circuit 5H of the inverter circuit 5. Each lower arm is composed of multiple switching elements 54 (54UL, 54VL, 54WL) connected to a second wiring 52N on the low-voltage side (low side) that connects the negative electrode of the battery 2 and the three-phase AC motor. The three lower arms form a low-side circuit 5L of the inverter circuit 5.

[0014] The high-side switching elements 54UH, 54VH, and 54WH corresponding to the U, V, and W phases are connected in series with the low-side switching elements 54UL, 54VL, and 54WL. The connection points between the high-side switching elements 54UH, 54VH, and 54WH and the low-side switching elements 54UL, 54VL, and 54WL are connected to the corresponding phases of the three-phase AC motor 4. Each switching element 54 is, for example, an nMOSFET (n-type metal-oxide-semiconductor field-effect transistor), and switches the power supplied to each phase of the three-phase AC motor 4.

[0015] The drain electrodes of the switching elements 54UH, 54VH, and 54WH that constitute the high-side circuit 5H are connected to the positive electrode side of the battery 2. The source electrodes of the switching elements 54UL, 54VL, and 54WL that constitute the low-side circuit 5L are connected to the negative electrode side of the battery 2. The gate electrodes of all the switching elements 54 are connected to signal lines for control signals output from a control unit 6, which will be described later.

[0016] The inverter circuit 5 converts the DC current between the first wiring 52P and the second wiring 52N into a three-phase AC current and supplies it to the three-phase AC motor 4.

[0017] The control unit 6 is a control circuit having a CPU (Central Processing Unit) (not shown) as a control IC and having the function of controlling the on / off states of multiple switching elements 54. The control unit 6 controls power conversion by controlling the operation of the multiple switching elements 54 based on current detected by a current sensor 7 (described later). As an example, the control unit 6 sets a fluctuation pattern of the current to be passed through each phase of the three-phase AC motor 4 based on an output torque request for the three-phase AC motor 4 from a host ECU of the vehicle. The control unit 6 feedback-controls the inverter circuit 5 so that the output current from the inverter circuit 5 to the three-phase AC motor 4 fluctuates in accordance with the set fluctuation pattern. That is, the control unit 6 drives each switching element 54 of the inverter circuit 5 based on the output current of the inverter circuit 5 detected by the current sensor 7.

[0018] The current sensor 7 is a device that detects the current flowing through the sensor area by detecting the strength of the magnetic field generated in the sensor area. The current sensor 7 is a non-contact current sensor that does not come into contact with the conductor to be measured, and is a sensor package that includes a semiconductor substrate on which a magnetoelectric conversion element such as a magnetoresistance effect element is formed. The current sensor 7 outputs a detection value as an electric signal that indicates, for example, the strength and direction of the magnetic field along a predetermined detection axis direction at its own position.

[0019] The circuit configuration of the electronic device 1 includes a plurality of current sensors 7, which are constituted by a first current sensor 7P, a second current sensor 7U, a third current sensor 7V, and a fourth current sensor 7W.

[0020] The first current sensor 7P detects the current flowing between the positive electrode of the battery 2 and the inverter circuit 5.

[0021] The second current sensor 7U, the third current sensor 7V, and the fourth current sensor 7W detect output currents flowing from the inverter circuit 5 to the U-phase, V-phase, and W-phase of the three-phase AC motor 4, and return currents output from the U-phase, V-phase, and W-phase of the three-phase AC motor 4. The second current sensor 7U, the third current sensor 7V, and the fourth current sensor 7W are electrically connected between the source electrodes of the switching elements 54 (54UH, 54VH, 54WH) constituting the high-side circuit 5H of each phase and the drain electrodes of the switching elements 54 (54UL, 54VL, 54WL) constituting the low-side circuit 5L.

[0022] Specifically, first connection wiring 53A and second connection wiring 53B are electrically connected between the source electrode of the switching element 54 constituting the high-side circuit 5H of each phase and the drain electrode of the switching element 54 constituting the low-side circuit 5L, and form part of wiring 52. The first connection wiring 53A electrically connects the source electrode of the switching element 54 constituting the high-side circuit 5H of each phase to the drain electrode of the switching element 54 constituting the low-side circuit 5L. The second connection wiring 53B electrically connects the first connection wiring 53A to input / output terminals (not shown) of each phase of the three-phase AC motor 4. Both output currents input from the inverter circuit 5 to the U, V, and W phases of the three-phase AC motor 4 and return currents output from the U, V, and W phases of the three-phase AC motor 4 flow through this second connection wiring 53B.

[0023] The second current sensor 7U, the third current sensor 7V, and the fourth current sensor 7W are arranged to detect the current flowing through the second connection wiring 53B.

[0024] It is not essential to provide the first current sensor 7P and detect the current flowing between the positive electrode of the battery 2 and the inverter circuit 5. The first current sensor 7P may be omitted.

[0025] In this embodiment, the capacitor 3, inverter circuit 5, control unit 6, and multiple current sensors 7 are housed inside a box-shaped housing 12 to form the electronic device 1. Furthermore, by assembling a terminal block 20 and a control board 60 to the housing 12 of the electronic device 1, the multiple current sensors 7 are arranged opposite the sensor area SA of the bus bar 30 through which the current to be detected flows. The mechanical configuration of the electronic device 1 will be described in detail below.

[0026] (Mechanical configuration of electronic device 1) FIG. 2 is a plan view of the inside of the housing of the electronic device 1, seen from above. FIG. 3 is a partial cross-sectional view of the electronic device 1. FIG. 4 is an enlarged plan view of the front of the housing 12, to which the terminal block 20 is attached, seen from above. As shown in FIGS. 2 to 4, the electronic device 1 has a box-shaped housing 12, a terminal block 20 fixed to the housing 12, and a plurality of bus bars 30 held by the terminal block 20. The electronic device 1 also has a switch board 50 and a control board 60 housed inside the housing 12. Note that in FIG. 2, for ease of understanding, only the outline of the control board 60 is shown by a two-dot chain line. The mechanical configuration of the electronic device 1 is not limited to this, and modifications and additions can be made as appropriate.

[0027] (Housing) The housing 12 is a rectangular box-shaped member made of metal and has an opening 13 that opens upward. The housing 12 includes a front wall 12A, a rear wall 12B, a left wall 12C, a right wall 12D, and a bottom wall 12E. The opening 13 of the housing 12 is closed by a lid-shaped cover member (not shown).

[0028] A terminal block mounting portion 16 for fixing the terminal block 20 is formed on the front wall portion 12A of the housing 12. The terminal block mounting portion 16 is a rectangular cutout hole that penetrates the front wall portion 12A and is open upward.

[0029] (terminal block) Terminal block 20 is a case member made of an insulating material such as resin, and has a case portion 22 that holds multiple bus bars 30 as electrical paths, and a flange portion 24 that protrudes from the outer peripheral surface of case portion 22. Case portion 22 is configured to hold each bus bar 30 and expose one end and the other end of each bus bar 30 in the longitudinal direction for connection to external wiring.

[0030] One longitudinal end of each bus bar 30 is exposed to the outside of the housing 12 while the terminal block 20 is fixed to the housing 12. This end is connected to a terminal (not shown) that is electrically connected to the battery 2 and the three-phase AC motor 4. As shown in FIG. 4 , the longitudinal end of each bus bar 30 and the terminal electrically connected to the battery 2 and the three-phase AC motor 4 are, for example, round terminals. The round terminals are connected to the longitudinal ends of the bus bars 30 by fastening members 42 such as bolts and nuts. For this reason, a plurality of partition walls 26 that protect the longitudinal ends of the bus bars 30 are integrally formed on the case portion 22 of the terminal block 20. Each partition wall 26 is disposed so as to separate two adjacent bus bars 30 and is provided on both sides of each bus bar 30. Each partition wall 26 functions as an insulating wall to ensure insulation between the bus bars 30. Furthermore, each partition wall 26 functions as a rotation stopper to prevent the bus bar 30 from rotating in the direction in which the fastening torque is input when one end of the bus bar 30 is fastened to the round terminal.

[0031] On the other hand, the other longitudinal end of each bus bar 30 is exposed inside the housing 12 with the terminal block 20 fixed to the housing 12. The other end is connected to wiring 52 provided on a switch board 50, which will be described later.

[0032] Furthermore, the flange portion 24 of the terminal block 20 has a groove portion 241 that fits onto the edge of the terminal block mounting portion 16. The terminal block 20 is configured so that, when inserted into the open end of the terminal block mounting portion 16, the groove portion 241 formed in the flange portion 24 fits onto the edge of the terminal block mounting portion 16. In other words, the terminal block 20 is fixed to the housing 12 via the flange portion 24.

[0033] (busbar) The bus bars 30 are arranged at predetermined intervals along the longitudinal direction (left-right direction in FIG. 2 and other figures) of the terminal block 20. Each bus bar 30 is made of a conductive material such as copper, and has a strip-like shape with its longitudinal direction extending in the front-to-rear direction of the housing 12.

[0034] As shown in Figures 5(A) and 5(B), each bus bar 30 has, as its main components, a first extending portion 31, a second extending portion 32, a third extending portion 33, a fourth extending portion 34, and a positioning portion 38.

[0035] The first extending portion 31 constitutes the base end side of the bus bar 30 and extends in the front-rear direction. The first extending portion 31 has a thickness direction in the up-down direction and a main surface facing the up-down direction. At least a portion of the first extending portion 31 is embedded in the terminal block 20 by insert molding or the like. The base end 31A of the first extending portion 31 constitutes one longitudinal end of the bus bar 30 and is disposed outside the housing 12. A connector of the battery 2 or the three-phase AC motor 4 is connected to the base end 31A of the first extending portion 31 by a fastening member 42. Note that one of a bolt and a nut constituting the fastening member 42 may be embedded in the terminal block 20 by insert molding or the like. Meanwhile, the tip 31B of the first extending portion 31 protrudes from the terminal block 20 and is disposed inside the housing 12. That is, the tip 31B of the first extending portion 31 extends from the terminal block 20 toward the housing 12.

[0036] The second extending portion 32 extends from the tip 31B of the first extending portion 31 in a direction different from that of the first extending portion 31. In a plan view, the second extending portion 32 is bent and extends diagonally rearward and left from the tip 31B of the first extending portion 31. Like the first extending portion 31, the second extending portion 32 has a thickness direction that is in the up-down direction, and has main surfaces that face in the up-down direction. One of the main surfaces of the second extending portion 32 forms a surface that faces the control board 60, which will be described later. A sensor area SA that faces the current sensor 7 is formed on this facing surface.

[0037] 5A shows the center line C1 of the first extending portion 31 and the center line C2 of the second extending portion 32 of the busbar 30. The angle θ1 formed between the center line C1 of the first extending portion 31 and the center line C2 of the second extending portion 32 corresponds to the inclination of the second extending portion 32 with respect to the first extending portion 31. The inclination of the second extending portion 32 is preferably set in consideration of the fact that, when the second extending portion 32 is viewed from a direction perpendicular to the center line C2 (see arrow A), the sensor area SA of the second extending portion 32 does not overlap with the sensor area SA of another adjacent busbar 30. From this perspective, the angle θ1 can be set, for example, between 0° and 90°, and is more preferably set to 90°. In this embodiment, the angle θ1 is set to 45°.

[0038] As shown in FIG. 5(A), the width W2 of the second extending portion 32 is set smaller than the width W1 of the first extending portion 31.

[0039] The third extending portion 33 extends from the tip of the second extending portion 32 in a direction different from that of the second extending portion 32. The third extending portion 33 extends leftward from the tip of the second extending portion 32 in a plan view. Like the first extending portion 31 and the second extending portion 32, the third extending portion 33 has a thickness direction that is vertical, and has a main surface that faces vertically. FIG. 5(A) shows the angle θ2 formed between the center line C3 of the third extending portion 33 and the center line C2 of the second extending portion 32. As an example, the angle θ2 is set to 45°. Therefore, the third extending portion 33 extends in a direction perpendicular to the first extending portion 31 in a plan view.

[0040] The fourth extending portion 34 extends from the tip of the third extending portion 33 in a direction different from that of the third extending portion 33. The fourth extending portion 34 extends rearward from the tip of the third extending portion 33 in a plan view. The fourth extending portion 34 has a main surface facing the left-right direction, with the left-right direction being the plate thickness direction. That is, the plane direction of the main surface of the fourth extending portion 34 is perpendicular to the main surfaces of the first extending portion 31, the second extending portion 32, and the third extending portion 33. FIG. 5A shows the angle θ3 formed between the center line C4 of the fourth extending portion 34 and the center line C3 of the third extending portion 33 in a plan view. The angle θ3 is set to 90°, for example. Therefore, the fourth extending portion 34 extends parallel to the first extending portion 31 in a plan view.

[0041] The positioning portion 38 is provided at the middle portion in the longitudinal direction of the fourth extending portion 34. The positioning portion 38 is formed as a protrusion that protrudes from the upper end portion of the fourth extending portion 34. A step portion 39 is formed at the middle portion in the protruding direction of the positioning portion 38. A control board 60, which will be described later, is placed on the upper surface of the step portion 39. The tip portion of the positioning portion 38 that protrudes upward beyond the step portion is fitted into a hole portion 62 provided in the control board 60, which will be described later.

[0042] In this embodiment, multiple bus bars 30 consisting of a first bus bar 30P, a second bus bar 30U, a third bus bar 30V, a fourth bus bar 30W, and a fifth bus bar 30N are arranged in this order along the longitudinal direction of the terminal block 20.

[0043] For example, one end of the first bus bar 30P is connected to a terminal extending from the positive electrode of the battery 2. Therefore, the current flowing through the first bus bar 30P corresponds to the current flowing between the positive electrode of the battery 2 and the inverter circuit 5.

[0044] For example, one end of the second bus bar 30U is connected to a terminal extending from the U phase of the three-phase AC motor 4. For example, one end of the third bus bar 30V is connected to a terminal extending from the V phase of the three-phase AC motor 4. For example, one end of the fourth bus bar 30W is connected to a terminal extending from the W phase of the three-phase AC motor 4. Therefore, the currents flowing through the second bus bar 30U, the third bus bar 30V, and the fourth bus bar 30W correspond to the currents output from the inverter circuit 5 to each phase of the three-phase AC motor 4.

[0045] For example, one end of the fifth bus bar 30N is connected to a terminal extending from the negative electrode of the battery 2. Therefore, the current flowing through the fifth bus bar 30N corresponds to the current flowing between the negative electrode of the battery 2 and the inverter circuit 5.

[0046] 3, a switch board 50 and a control board 60 are housed facing each other in the vertical direction inside the housing 12. A plurality of bus bars 30 extending from the terminal block 20 are arranged between the switch board 50 and the control board 60.

[0047] (switch board) An inverter circuit 5 is mounted on the switch substrate 50. The switch substrate 50 is made of a heat dissipation substrate, and wiring 52 is provided on a metal base substrate with high thermal conductivity via an insulating layer (see FIG. 2). The wiring 52 includes first wiring 52P and second wiring 52N that connect the circuit configuration of the electronic device 1. A plurality of switching elements 54 that form upper and lower arms of the inverter circuit 5 are connected to the wiring 52.

[0048] Furthermore, a plurality of connection terminals 40 standing upright on the surface of the switch board 50 are connected to the switch board 50. Tips of the plurality of connection terminals 40 are joined to the main surfaces of the fourth extension portions 34 of the corresponding bus bars 30 by welding or the like. As a result, the plurality of bus bars 30 held by the terminal block 20 are connected to the wiring 52 via the plurality of connection terminals 40.

[0049] (control board) The control board 60, which serves as the board on which the current sensor 7 is mounted, is configured, for example, as a rectangular printed wiring board. The control unit 6, which controls the operation of the multiple switching elements 54, is mounted on the control board 60. The control board 60 and the switch board 50 are connected in the vertical direction by conductor pins (not shown). The conductor pins electrically connect the signal lines of the control unit 6 to the wiring 52 of the switch board 50 (the gate electrodes of the switching elements 54).

[0050] The lower surface of the front end of the control board 60 is an area facing the second extension portion 32 of the bus bar 30. A plurality of current sensors 7 are mounted in this facing area so as to face the sensor area SA of the second extension portion 32 (see FIG. 4). Each current sensor 7 is disposed facing the sensor area SA formed on the second extension portion 32 of the corresponding bus bar 30. The detection axis of each current sensor 7 is aligned along a direction perpendicular to the extension direction of the second extension portion 32 (the direction of arrow A in FIG. 5A). Therefore, the current sensor 7 detects a concentric magnetic field centered on the second extension portion 32 at a position facing the main surface of the second extension portion 32.

[0051] Specifically, the first current sensor 7P faces the sensor area SA of the first bus bar 30P and detects the current flowing between the positive electrode of the battery 2 and the inverter circuit 5. The second current sensors 7U to fourth current sensors 7W face the sensor areas SA of the second bus bar 30U to fourth bus bar 30W, respectively, and detect the current output from the inverter circuit 5 to each phase of the three-phase AC motor 4. The fifth current sensor 7N faces the sensor area SA of the fifth bus bar 30N and detects the current flowing between the negative electrode of the battery 2 and the inverter circuit 5.

[0052] Furthermore, a plurality of holes 62 are formed in the front end of the control board 60 near the mounting positions of the current sensors 7. The plurality of holes 62 are through-holes that penetrate the control board 60 in the board thickness direction, and correspond to the protrusions of the positioning portions 38 formed on the busbar 30. That is, the positioning portions 38 formed on the busbar 30 protrude toward the control board 60 and are inserted into the holes 62 that correspond to the control board 60. This allows the control board 60 to be positioned relative to the busbar 30 in the front-rear and left-right directions. Furthermore, the control board 60 is positioned relative to the busbar 30 in the up-down direction by being placed on the upper surface of a step portion 39 formed on the positioning portion 38. Since the control board 60 and the switch board 50 are connected in the vertical direction by a conductor pin (not shown), the step portion 39 is not essential. However, by providing the step portion 39, it is possible to perform vertical positioning near the corresponding hole portion 62 of the control board 60, thereby improving the positioning accuracy.

[0053] (Action and effect) As described above, the electronic device 1 according to the first embodiment includes a current sensor 7 that is disposed opposite an electric path that constitutes a circuit and that detects a current flowing in the electric path based on a magnetic field generated around the electric path. Specifically, the electronic device 1 includes a bus bar 30 that serves as an electric path held by a terminal block 20, and a current sensor 7 that is disposed opposite the bus bar 30. The current sensor 7 is configured to detect a current flowing in the bus bar 30 based on a magnetic field generated around the bus bar 30.

[0054] The busbar 30 includes a first extension portion 31 extending along a first direction (the direction of the center line C1) and a second extension portion 32 extending along a second direction (the direction of the center line C2) different from the first direction, and a sensor area SA facing the current sensor 7 is formed in the second extension portion 32. Therefore, the direction of the magnetic field generated around the busbar 30 changes to a direction different from that of the first extension portion 31 in the second extension portion 32 where the sensor area SA is provided.

[0055] 5(B), a concentric magnetic field M1 is generated around the first extension portion 31 of the busbar 30, with the first extension portion 31 at its center, while a concentric magnetic field M2 is generated around the second extension portion 32, with the second extension portion 32 at its center. Therefore, in the sensor area SA of the second extension portion 32, mutual coupling with magnetic fields generated by the first extension portions 31 of other busbars 30 arranged parallel to the first extension portion 31 and the wiring of the switch board 50 is less likely to occur, thereby suppressing crosstalk. As a result, the current detection accuracy of the current sensor 7 can be improved.

[0056] In addition, in this embodiment, the first extending portion 31 of the busbar 30 extends from the terminal block 20 toward the housing 12 in the first direction, and the second extending portion 32 is configured to bend and extend from the tip of the first extending portion 31. Therefore, the sensor area SA facing the current sensor 7 is formed in the vicinity of the first extending portion 31 supported by the housing 12 and the terminal block 20. This stabilizes the positioning of the sensor area SA of the busbar 30 relative to the current sensor 7 and makes it less likely to be misaligned, thereby effectively improving the current detection accuracy.

[0057] In this embodiment, the width W2 of the second extending portion 32 of the busbar 30 is set smaller than the width W1 of the first extending portion 31. Therefore, the width of the busbar 30 can be made smaller in the sensor region SA facing the current sensor 7 than in other regions, which effectively suppresses crosstalk due to mutual coupling with the surrounding magnetic field.

[0058] In this embodiment, a control board 60 is provided facing the busbar 30, and the current sensor 7 is mounted on the opposing area of ​​the control board 60. The busbar 30 has a positioning portion 38 formed as a protrusion that protrudes toward the control board 60. The positioning portion 38 fits into a hole 62 provided on the control board 60. This positions the current sensor 7 mounted on the control board 60 relative to the sensor area SA of the busbar 30 in the front-rear and left-right directions. Furthermore, a step portion 39 formed on the positioning portion 38 positions the current sensor 7 relative to the sensor area SA of the busbar 30 in the up-down direction. In this configuration, the positioning portion 38 is integral with the busbar 30, which reduces the influence of misalignment due to tolerances compared to when positioning is performed via a separate component. This improves the accuracy of positioning the sensor area SA of the busbar 30 relative to the current sensor 7.

[0059] Furthermore, in this embodiment, at least some of the multiple current sensors 7 measure the current flowing between the power supply (battery 2) and the power supply target (three-phase AC motor 4) between the source electrodes of the high-side switching elements 54UH, 54VH, and 54WH and the drain electrodes of the low-side switching elements 54UL, 54VL, and 54WL. Therefore, the output current to the three-phase AC motor 4 can be detected at a position where the influence of loss due to the switching elements 54 is small, thereby improving the current detection accuracy.

[0060] Second Embodiment An electronic device 70 according to the second embodiment will be described below with reference to Figs. 6 to 9(B). This electronic device 70 is characterized in that a first extension 91 included in an electric path 90 constituting a circuit is configured by a terminal member 82 mounted on a substrate 80, and a second extension 92 included in the electric path 90 is configured by a wiring pattern 84 formed on the substrate. Note that the circuit configuration of the electronic device 70 is the same as the circuit configuration of the electronic device 1 of the first embodiment described above (see Fig. 1), and therefore a detailed description thereof will be omitted. Furthermore, in the following description, the same components as those of the first embodiment will be assigned the same reference numerals, and a detailed description thereof will be omitted.

[0061] 6 is an exploded perspective view of the electronic device 70. As shown in this figure, the electronic device 70 has a configuration in which a substrate 80 is housed inside a flat box-shaped housing 72.

[0062] The housing 72 includes a heat dissipation plate 74 that forms the bottom of the electronic device 70, and a lid member 76 that covers the heat dissipation plate 74 from above. The heat dissipation plate 74 is formed in a plate shape using a highly heat-dissipating material such as metal, and has an upper surface 74A that is formed as a flat surface, and a lower surface 74B that is integrally formed with a plurality of fins 75. A substrate 80, which will be described later, is placed on the upper surface 74A.

[0063] The cover member 76 is bathtub-shaped and opens downward, and is made of a material such as metal or resin. The cover member 76 and the heat dissipation plate 74 are joined at their outer peripheries via fastening members 77 such as bolts and nuts. The top surface of the cover member 76 is formed with a plurality of terminal openings 761 through which first extension portions 92 (described later) are inserted, and at least one connector opening 762. A connector 78 mounted on a circuit board 80 (described later) is inserted into the connector opening 762. A connector (not shown) electrically connected to the battery 2 and the three-phase AC motor 4 is connected to the connector 78.

[0064] (substrate) 7 is a plan view of a substrate 80 on which a current sensor 7 is mounted. The substrate 80 is, for example, a multilayer printed wiring board. The circuit components mounted on the substrate 80 are a capacitor 3, an inverter circuit 5, a control unit 6, and a current sensor 7 (see FIG. 1). These circuit elements are electrically connected by an electrical path 90 made up of terminal members, wiring patterns, etc.

[0065] (Electric circuit) Fig. 8 is a partially enlarged perspective view of the substrate 80, showing an enlarged view of the terminal members 82 and wiring pattern 84 that make up the electrical circuit 90. Fig. 9(A) is a cross-sectional view taken along line 9A-9A in Fig. 8, and Fig. 9(B) is a cross-sectional view taken along line 9B-9B in Fig. 8. As shown in Figs. 8 to 9(B), the electrical circuit 90 has a plurality of terminal members 82 mounted on the substrate 80 and a wiring pattern 84 formed on the substrate 80.

[0066] (Terminal material) Each terminal member 82 is configured, for example, by a cylindrical screw terminal. The terminal member 82 has a small-diameter protrusion 821 that is inserted into a through-hole 86 of the circuit board 80, and a large-diameter protrusion 822 that stands upright from the upper surface of the circuit board 80. A female screw 823 is formed on the upper part of the large-diameter protrusion 822, and the female screw 823 is configured to be threadedly engaged with a screw member 102 that is inserted into a round terminal 101 extending from the battery 2 and the three-phase AC motor 4. This electrically connects the positive and negative electrodes of the battery 2 and each phase of the three-phase AC motor 4 to the multiple terminal members 82.

[0067] The multiple terminal members 82 are arranged in a row along one of the four sides of the substrate 80 that constitutes the rear edge. Each terminal member 82 is erected on the surface of the substrate 80 and extends in the thickness direction of the substrate 80. This terminal member 82 constitutes a first extending portion 91 of the electric circuit 90 of the electronic device 70 that extends along the thickness direction of the substrate 80. In this embodiment, the thickness direction of the substrate 80 is an example of the first direction of the electric circuit 90.

[0068] (wiring pattern) Next, the wiring pattern 84 will be described. A portion of the wiring pattern 84 constitutes a second extending portion 92, a third extending portion 93, a fourth extending portion 94, and a fifth extending portion 95 of the electrical path 90. The second extending portion 92, the third extending portion 93, the fourth extending portion 94, and the fifth extending portion 95 are wiring patterns whose main surfaces are in the vertical direction of the substrate 80.

[0069] The second extension portion 92 is a wiring pattern 84 formed on the upper surface of the substrate 80 and extends in the left-right direction along the rear edge of the substrate 80. A right end of the second extension portion 92 is connected to the terminal member 82 constituting the first extension portion 91. In this embodiment, the left-right direction of the substrate 80 is an example of the second direction of the electric path 90 and is a direction perpendicular to the thickness direction of the substrate 80. That is, in this embodiment, the second extension portion 92 extends in a direction perpendicular to the first extension portion 91. Therefore, similar to the busbar 30 of the first embodiment, the direction of the magnetic field generated around the electric path 90 when energized is configured to be different between the first extension portion 91 and the second extension portion 92. Therefore, crosstalk due to coupling between the magnetic field generated around the first extension portion 91 (M3 shown in FIG. 9A) and the magnetic field generated around the second extension portion 92 (M4 shown in FIG. 9A) when energized is suppressed.

[0070] Here, a sensor area SA facing the current sensor 7 mounted on the underside of the substrate 80 is provided in the middle of the second extension portion 92 in the extension direction (see FIG. 9A). That is, the sensor area SA of the second extension portion 92 faces the current sensor 7 via the insulating layer 801 of the substrate 80. In this embodiment, the four second extension portions 92 are arranged in a row along one of the four sides of the substrate 80 that constitutes the rear edge. Furthermore, four current sensors 7 (7P, 7U, 7V, 7W) are arranged on the underside of the substrate 80 so as to face the sensor areas SA of the four second extension portions 92. In this configuration, adjacent second extension portions 92 are not arranged parallel to each other, thereby suppressing crosstalk between adjacent second extension portions 92 due to coupling between surrounding magnetic fields (M4 shown in FIG. 9A). This improves the current detection accuracy of the current sensor 7.

[0071] Furthermore, a notch 921 narrowed in the width direction is formed in the sensor region SA of the second extending portion 92 (see FIG. 8). Therefore, the width W4 of the sensor region SA is set smaller than the width W3 of the other region of the second extending portion 92. This allows the width of the second extending portion 92 to be smaller in the sensor region SA facing the current sensor 7 than in the other region, thereby effectively suppressing the occurrence of crosstalk due to mutual coupling with the surrounding magnetic field.

[0072] The third extension portion 93 of the electrical circuit 90 is a wiring pattern 84 formed on the upper surface of the substrate 80, and extends from the other end of the second extension portion 92 in a direction different from that of the second extension portion 92. In this embodiment, the third extension portion 93 extends from the left end of the second extension portion 92 toward the front side in a direction perpendicular to the second extension portion 92.

[0073] Furthermore, the fourth extension portion 93 of the electrical path 90 is a wiring pattern 84 formed on the upper surface of the substrate 80, and extends from the front end of the third extension portion 93 in a direction different from that of the third extension portion 93. In this embodiment, the fourth extension portion 94 extends from the front end of the third extension portion 93 toward the right in a direction perpendicular to the third extension portion 93.

[0074] Furthermore, the fifth extension portion 95 of the electrical circuit 90 is a wiring pattern 84 formed on the lower surface of the substrate 80, and extends from a middle portion in the extension direction of the fourth extension portion 94 in a direction different from that of the fourth extension portion 94 (see FIG. 9(B)). In this embodiment, the fifth extension portion 94 is connected to the fourth extension portion 94 via a through hole 88 formed in the substrate 80, and extends forward from the fourth extension portion 94 in a direction perpendicular to the fourth extension portion 94.

[0075] A plurality of switching elements 54 constituting the inverter circuit 5 as a switching circuit are electrically connected to the fifth extension portion 95. That is, a plurality of switching elements 54 are mounted on the lower surface of the substrate 80. Each switching element 54 has a heat dissipation portion 54A that exposes a heat sink, and the heat dissipation portion 54A is disposed facing the upper surface 74A of the heat dissipation plate 74. In this embodiment, the heat dissipation portion 54A abuts against the upper surface 74A of the heat dissipation plate 74 via an insulating sheet (not shown). This allows heat generated in the switching elements 54 when current is applied to be quickly dissipated to the outside via the heat dissipation plate 74. Note that the small-diameter protrusions 821 of the terminal members 82 may abut against the upper surface 74A of the heat dissipation plate 74 via an insulating sheet (not shown).

[0076] (Action and effect) As described above, the electronic device 70 according to the second embodiment includes a current sensor 7 disposed opposite an electric circuit 90 constituting a circuit and configured to detect a current flowing through the electric circuit 90 based on a magnetic field generated around the electric circuit 90. Specifically, the electronic device 70 includes a substrate 80 on which a plurality of current sensors 7 are mounted. The first extension 91 of the electric circuit 90 is formed by a terminal member 82 erected on the surface of the substrate 80 and extending in the thickness direction of the substrate 80. The second extension 92 is formed by a wiring pattern 84 formed on the substrate 80 and extending in a direction perpendicular to the thickness direction of the substrate 80. As a result, the direction of the magnetic field generated around the electric circuit 90 is changed in the second extension 92, where the sensor area SA is provided, from the direction of the first extension 91. This reduces mutual coupling with magnetic fields generated by surrounding terminal members, wiring, and the like arranged parallel to the first extension 91, thereby suppressing crosstalk. As a result, the current detection accuracy of the current sensor 7 can be improved.

[0077] In addition, in this embodiment, the current sensor 7 is disposed opposite the sensor area SA of the second extension portion 92 via the insulating layer 801 of the substrate 80. Therefore, since the second extension portion 90 and the current sensor 7 are provided on the same substrate 80, the positioning accuracy between the sensor area SA and the current sensor 7 is improved and the number of connection terminals can be reduced.

[0078] In addition, in this embodiment, the width W4 of the sensor region SA is set smaller than the width W3 of the other region of the second extending portion 92. This makes it possible to effectively suppress the occurrence of crosstalk due to mutual coupling with the surrounding magnetic field.

[0079] Furthermore, in this embodiment, the substrate 80 has a plurality of second extending portions 92 arranged in a row along one side (second direction) that constitutes the rear edge of the four sides of the substrate 80. This prevents crosstalk from occurring between adjacent second extending portions 92.

[0080] In addition, the electronic device 70 according to the second embodiment basically follows the configuration of the electronic device 1 according to the first embodiment, and therefore can achieve the same effects.

[0081] The electronic device 1 according to the first embodiment and the electronic device 70 according to the second embodiment have been described above, but the present invention is not limited to these. Modifications of the above embodiments are listed below. Each modification basically follows the configuration of the electronic device according to the above embodiments, and therefore can achieve the same functions and effects.

[0082] (First Modification) Although not shown, in the first embodiment, the number of bus bars 30 held by the terminal block 20 may be one or five or more. In the second embodiment, the number of terminal members 82 mounted on the substrate 80 may be one or five or more.

[0083] (Second Modification) As shown in Fig. 6, in the first embodiment, a configuration may be adopted in which multiple positioning portions 38 are provided on the bus bar 30. In Fig. 6, two positioning portions 38 are formed on the fourth extension portion 34 of the bus bar 30. By forming multiple positioning portions 38, even if the number of bus bars 30 held by the terminal block 20 is small, it is possible to control the rotational deviation of the control board 60 relative to the bus bars 30, and it is possible to stabilize the positioning of the bus bars 30 and the control board 60.

[0084] (Third Modification) In the first embodiment, the busbar 30 is configured to include the first extending portion 31, the second extending portion 32, the third extending portion 33, and the fourth extending portion 34, but is not limited to this. One or both of the third extending portion 33 and the fourth extending portion 34 may be omitted. In this case, the positioning portion 38 may be provided on at least one of the first extending portion 31 and the second extending portion 32.

[0085] (Fourth Modification) In the first embodiment, the positioning portion 38 is provided on the fourth extending portion 34 of the busbar 30, but this is not limiting. The positioning portion 38 may be provided on at least one of the first extending portion 31, the second extending portion 32, and the third extending portion 33.

[0086] (Fifth Modification) In the first embodiment, the positioning portion 38 of the bus bar 30 is configured to fit into the hole 62 that penetrates the control board 60, but this is not limiting. Although not shown, a recess may be formed by recessing the surface of the control board 60, and the protrusion of the positioning portion 38 may fit into the recess.

[0087] (Sixth Modification) In the first and second embodiments, three current sensors 7U, 7V, and 7W are provided on the second connection wiring 53B to detect the output current flowing from the inverter circuit 5 to each phase of the three-phase AC motor 4 and the return current output from each phase of the three-phase AC motor 4. However, the present invention is not limited to this.

[0088] 11 , current sensors 7U, 7V, and 7W may be connected to first connection wiring 53A that electrically connects the source electrodes of switching elements 54 constituting high-side circuits 5H and drain electrodes of switching elements 54 constituting low-side circuits 5L for each phase of a three-phase AC motor 4. In this case, current sensors 7 may be disposed on both sides of a connection point between first connection wiring 53A and second connection wiring 53B for each layer. This makes it possible to detect both the output current to the three-phase AC motor 4 and the return current from the three-phase AC motor 4. That is, in the U phase, current sensor 7U1 is provided on the higher potential side of the connection point with second connection wiring 53B, and current sensor 7U2 is provided on the lower potential side of the connection point with second connection wiring 53B. Similarly, in the V phase, a current sensor 7V1 is provided on the high potential side and a current sensor 7V2 is provided on the low potential side, and in the W phase, a current sensor 7W1 is provided on the high potential side and a current sensor 7W2 is provided on the low potential side. [Explanation of symbols]

[0089] 1 Electronic equipment 2 Battery (power source) 4 Three-phase AC motor (power supply target) 5 Inverter circuit (switching circuit) 5H High side circuit 5L Low-side circuit 12. Case 20 Terminal block 30 Busbar (electrical circuit) 31 1st extension part 32 Second extension part 38 Positioning part 54 Switching element 60 Control board (board) 62 Hole C1 1st direction C2 2nd direction SA sensor area W1 Width of the first extension W2 Width of the second extension

Claims

1. An electronic device including a current sensor that is disposed opposite an electric path that constitutes a circuit and detects a current flowing through the electric path based on a magnetic field generated around the electric path, The electronic device, wherein the electrical path has a first extension portion extending along a first direction and a second extension portion extending along a second direction different from the first direction and including a sensor area facing the current sensor.

2. The housing and a terminal block fixed to the housing; a bus bar as the electric path held by the terminal block; an electronic device including the current sensor disposed opposite the bus bar and configured to detect a current flowing through the bus bar based on a magnetic field generated around the bus bar, wherein the bus bar has the first extension portion extending from the terminal block toward the housing along the first direction, and the second extension portion bending from a tip of the first extension portion and extending along the second direction different from the first direction, The electronic device of claim 1 .

3. The width of the second extending portion of the bus bar is set smaller than the width of the first extending portion.

3. The electronic device of claim 2.

4. a substrate facing the bus bar and on which the current sensor is mounted; the bus bar has at least one positioning portion formed in a protrusion that protrudes toward the substrate, that fits into a recess or a hole formed in the substrate, and that positions the sensor region relative to the current sensor; The electronic device according to any one of claims 1 to 3.

5. a substrate on which the current sensor is mounted; the first extension portion is formed by a terminal member that is erected on the surface of the substrate and extends in a thickness direction of the substrate, the second extension portion is formed on the substrate and is configured by a wiring pattern extending in a direction perpendicular to the thickness direction, the current sensor is disposed opposite the sensor region of the second extension portion via an insulating layer of the substrate; The electronic device of claim 1 .

6. The width of the sensor region is set smaller than the width of the other region of the second extension portion.

6. The electronic device of claim 5.

7. The substrate has a direction along one of four sides of the substrate as the second direction, and a plurality of second extension portions are arranged in a row along the one side.

7. The electronic device according to claim 5 or 6.

8. a detection target of the current sensor is a switching circuit that controls the supply of power between a power source and a power supply target, and has a high-side circuit connected to a positive electrode side of the power source with respect to the power supply target, and a low-side circuit connected to a negative electrode side of the power source with respect to the power supply target; the electrical path is electrically connected between a source electrode of a switching element constituting the high-side circuit and a drain electrode of a switching element constituting the low-side circuit; The electronic device of claim 1 .

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