JP5840527B2 - Circuit board - Google Patents

Description

  The present invention relates to a circuit board provided with a shunt resistor.

  2. Description of the Related Art Conventionally, in a circuit board on which a circuit pattern is formed, a technique (1) is known in which when a high output such as a high voltage or a large current is realized, the wiring resistance is reduced by increasing the thickness of the circuit pattern. In addition, in a circuit board having circuit patterns formed on the front and back surfaces of an insulating plate, a technique for providing a through hole in a circuit pattern between components through which a large current flows, and soldering by inserting a jumper wire into the through hole (2) Is known (see, for example, Patent Document 1). Furthermore, a technique (3) for increasing a current capacity by connecting a conductor wire to a circuit pattern has been proposed.

Japanese Patent No. 3827158

However, when the thickness of the circuit pattern is increased (1), the amount of conductive material (for example, copper) used for the circuit pattern is increased, which increases the cost. Further, when soldering the jumper wires (2), a large number of through holes as current paths must be provided, and the circuit board becomes large. Further, in the circuit board in which a plurality of circuit components connected in parallel and a shunt resistor for current detection connected in series to these circuit components are connected to the circuit pattern, the plurality of circuit components and the shunt resistor are connected. When connecting the conductor wires to the resistor circuit pattern as described above (3), some of the conductor wires cannot be connected in a straight line, and the resistance between the plurality of circuit components and the shunt resistor is different. Current flowing from each circuit component to the shunt resistor becomes unbalanced, and as a result, current detection may not be performed accurately.
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a circuit board capable of preventing current imbalance.

In order to achieve the above object, the present invention provides a circuit board in which a conductor for increasing a current capacity of a circuit pattern is provided, and a shunt resistor for current detection is connected to the circuit pattern. A plurality of pairs of input terminals and output terminals connected to each other are provided, and the conductor is connected to a position where current density flowing into each input terminal of the shunt resistor or current density flowing out from each output terminal is made equal. It is characterized by that.
According to the above configuration, since a plurality of pairs of input terminals and output terminals are provided in the shunt resistor, for example, even when the shunt resistor is connected to a plurality of circuit components connected in parallel, the conductors are arranged linearly. Is possible. In addition, the resistance value of the shunt resistor increases if the current density flowing through the plurality of terminals is not uniform, but the current density flowing into each input terminal of the shunt resistor or the current density flowing out from each output terminal is made equal. Since the conductor is connected to the position, an increase in the apparent resistance value can be prevented.

In the above configuration, the shunt resistor may have a current path from the input terminal to the output terminal above the circuit pattern.
According to the above configuration, since the mounting area of the shunt resistor is reduced, the circuit board can be reduced in size.

The said structure WHEREIN: You may laminate | stack the board | substrate layer in which the said circuit pattern was formed, and the conductor layer in which the said conductor pattern was formed.
According to the above configuration, since the conductor can be provided on the circuit board by laminating the board layer and the conductor layer, the circuit board can be easily formed as compared with the case where the conductor is individually attached to the circuit board.

  According to the present invention, since a plurality of pairs of input terminals and output terminals are provided in the shunt resistor, for example, even when the shunt resistor is connected to a plurality of circuit components connected in parallel, the conductor is arranged in a straight line. This can prevent current imbalance. Further, since the conductor is connected at a position where the current density flowing into each input terminal of the shunt resistor or the current density flowing out from each output terminal is made equal, an increase in the apparent resistance value of the shunt resistor can be prevented.

  Further, since the shunt resistor has a current path from the input terminal to the output terminal above the circuit pattern, the mounting area of the shunt resistor is reduced, and the circuit board can be downsized.

  In addition, since the circuit board is configured by laminating a substrate layer on which a circuit pattern is formed and a conductor layer on which a conductor pattern is formed, the conductor is formed on the circuit board by laminating the substrate layer and the conductor layer. Since it can be provided, the circuit board can be easily formed as compared with the case where the conductors are individually attached to the circuit board.

It is a figure which shows the electrical constitution of the motor drive device using the circuit board which concerns on embodiment of this invention. It is a perspective view which shows a power drive unit from the upper surface side of a board | substrate. It is a perspective view which shows a power drive unit from the lower surface side of a board | substrate. It is a figure which shows shunt resistance, (A) is a front view, (B) is a side view, (C) is an expanded view. It is a schematic diagram which shows a part of circuit board. It is sectional drawing which shows a circuit board typically.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing an electrical configuration of a motor driving device using a circuit board according to the present embodiment.
This motor drive device 1 is an in-vehicle device mounted on an electric vehicle or a hybrid vehicle, and an electronic control unit (ECU) 10 that functions as a control device (active unit), and actually for driving a vehicle. A power drive unit (Power Drive Unit: PDU) 20 that functions as an active unit (also referred to as a power module) that drives the motor (drive source) 30 is provided. The electronic control unit 10 and the power drive unit 20 are connected in a plurality ( In this configuration, six harnesses (wirings) UH, UL, VH, VL, WH, WL are used.

The power drive unit 20 is a power conversion unit that drives a motor 30 as a drive source by current control using switching elements (transistors 31H and 31L) under the control of the electronic control unit 10, and is a high-voltage side input terminal on the input side. 13 and the low-voltage side input terminal 14 are connected to an external power supply 12 that is an in-vehicle battery, and a three-phase AC motor 30 is connected to the U-phase output terminal 15, V-phase output terminal 16, and W-phase output terminal 17 on the output side. Is connected.
The power drive unit 20 is provided between the high-voltage side input terminal 13 and the low-voltage side input terminal 14, and is supplied from the external power supply 12 and a smoothing capacitor 22 that smoothes the DC power supplied from the external power supply 12. An inverter circuit 23 that converts a direct current into an alternating current motor drive current and outputs it to the motor 30; and a gate drive substrate 25 on which a gate drive circuit 24 that drives the transistors 31H and 31L of the inverter circuit 23 are arranged. Yes.

The inverter circuit 23 is a PWM inverter based on pulse width modulation (PWM), and bridge-connects a high potential side transistor 31H and a low potential side transistor 31L that form a pair for each of the U phase, V phase, and W phase. The gate drive circuit 24 turns on / off the transistors 31H and 31L (six in this configuration).
For each of the transistors 31H and 31L, a switching transistor (switching element) such as an insulated gate transistor (IGBT) or MOSFET that is a power semiconductor is used.

The high potential side transistor 31H of each phase is connected to the high potential side to constitute a high side arm, and the low potential side transistor 31L of each phase is connected to the low potential side to constitute a low side arm.
The commutation diodes 32H and 32L are connected between the collectors and emitters of the transistors 31H and 31L. The commutation diodes 32H and 32L are connected to the collectors from the emitter side of the transistors 31H and 31L while the transistors 31H and 31L are off. It is comprised so that an electric current may flow into the side.

In the present embodiment, the transistor 31H and the commutation diode 32H, and the transistor 31L and the commutation diode 32L include power elements 33UH, 33UL, 33VH, 33VL, 33WH, and 33WL (hereinafter referred to as 33UH to 33WL) for each phase. ). Although not shown in FIG. 1, the power elements 33UH to 33WL are provided in plural (four in this embodiment).
Each phase is provided with a shunt resistor 40 for current detection.

  A control signal from the electronic control unit 10 is input to the gate drive circuit 24. More specifically, the gate drive circuit 24 is provided in pairs for each of the U-phase, V-phase, and W-phase, and the U-phase gate drive circuit 24 is connected to the U-phase via harnesses UH and UL. The V-phase gate drive circuit 24 receives the V-phase control signal via the harnesses VH and VL, and the W-phase gate drive circuit 24 passes the harnesses WH and WL. A W-phase control signal is input.

Each gate drive circuit 24 can supply a gate voltage to each of the transistors 31H and 31L, and controls the gate voltage of each of the transistors 31H and 31L to be on (Hi level) / off (Low level) by the input control signal. Thus, the transistors 31H and 31L are switched, the U-phase current is output from the U-phase output terminal 15, the V-phase current is output from the V-phase output terminal 16, and the W-phase current is output from the W-phase output terminal 17. Let
That is, two harnesses UH to WL are connected to the power drive unit 20 for each phase, and a pair of control signals are input to each phase via these harnesses UH to WL to generate and output a current for each phase. It has become so.

FIG. 2 is a perspective view showing the power drive unit 20 from the upper surface side. FIG. 3 is a perspective view showing the power drive unit 20 from the lower surface side. 4A and 4B are diagrams showing the shunt resistor 40. FIG. 4A is a front view, FIG. 4B is a side view, and FIG. 4C is a development view.
The power drive unit 20 includes a substantially rectangular circuit board 21 on which electronic components such as a smoothing capacitor 22, power elements 33UH to 33WL, and a shunt resistor 40 are arranged. Although not shown in the figure, the circuit board 21 is connected to devices such as a control device and a vehicle driving motor. 2 and 3, the front side of the short side of the circuit board 21 is the front side, the back side is the rear side, the left side of the long side is the left side, and the right side is the right side.

  The smoothing capacitor 22 includes a plurality (five in the present embodiment) of electrolytic capacitors 26 and one film capacitor 27. The plurality of electrolytic capacitors 26 are arranged in a line along the longitudinal direction of the circuit board 21 at a substantially central portion in the short-side direction of the circuit board 21. Two electrolytic capacitors 26 are disposed adjacent to one side (front side) in the short direction of the circuit board 21 and adjacent to the other side (rear side) in the short direction of the circuit board 21. The film capacitor 27 is disposed at one corner located on the rear side of the circuit board 21. The electrolytic capacitor 26 and the film capacitor 27 are each formed in a substantially cylindrical shape. The electrolytic capacitor 26 is disposed on the circuit board 21 with the axis directed in the vertical direction and the film capacitor 27 oriented in the horizontal direction (left-right direction). Yes.

  On one side (left side) of the arranged film capacitors 27, power elements 33VH, 33WH, 33UH on the high potential side from the front side of the circuit board 21 are arranged, and on the other side (right side) of the film capacitors 27 from the front side. Low-potential side power elements 33VL, 33WL, and 33UL are arranged. The power elements 33 </ b> UH to 33 </ b> WL are formed in a substantially plate shape, and are arranged vertically so that the flat portion 33 extends along the longitudinal direction of the circuit board 21. As a result, the mounting area of the power elements 33UH to 33WL is reduced as compared with the case where the power elements are placed flat on the circuit board 21, so that the circuit board 21 can be downsized.

Of the four power elements 33UH, the two power elements 33UH are integrally provided adjacent to each other, and the remaining two power elements 33UH are integrally provided adjacent to the two power elements 33UH. Since the power elements 33VH, 33WH, 33UL, 33VL, and 33WL have the same arrangement configuration as that of the power element 33UH, description thereof is omitted.
On the downstream side (ground side) of the power elements 33UL, 33VL, and 33WL (hereinafter referred to as 33UL to 33WL), a shunt resistor 40 is disposed substantially perpendicular to the power elements 33UL to 33WL. More specifically, one shunt resistor 40 is disposed between the power elements 33VL and 33WL, the second shunt resistor 40 is disposed between the power elements 33WL and 33UL, and the third shunt resistor 40 includes the power element 33UL and the circuit board 21. It is arranged between the rear short side.

  As shown in FIG. 4, the shunt resistor 40 includes an arch-shaped main body 41, a plurality of (in this embodiment, five) input terminals 42 at one end of the main body 41, and a plurality ( In the present embodiment, five output terminals 43 are attached. As shown in FIG. 3, the shunt resistor 40 is vertically arranged so that the flat portion 44 of the main body 41 is along the short direction of the circuit board 21.

  Since the circuit board 21 has a configuration in which the shunt resistor is arranged on the ground side, if a general plate-like shunt resistor (about 10 W) is placed flat on the circuit board 21, the length of the circuit board 21 is increased. As the direction dimension increases, the dead space of the circuit board 21 increases. Therefore, in the present embodiment, as described above, the shunt resistor 40 is arched so that the current path from the input terminal 42 to the output terminal 43 passes over the component mounting surface (the front and back surfaces of the circuit board 21). Since the circuit board 21 is vertically arranged on the circuit board 21, the mounting area of the shunt resistor 40 in the longitudinal direction of the circuit board 21 can be reduced, and the circuit board 21 can be downsized. In addition, since the current path can be secured by making the shunt resistor 40 arched, a large current and a high heat dissipation can be realized. Further, since a through hole as a current path becomes unnecessary, the circuit board 21 can be reduced in size.

  Note that the terminals 22A, 33A, 42, and 43 of the electronic components such as the smoothing capacitor 22, the power elements 33UH to 33WL, and the shunt resistor 40 are inserted through the insertion holes 22B, 33B, 42B, and 43B of the circuit board 21, respectively. A THD (Through Hole Mount Device) type component to be mounted. These electronic components are fixed to the circuit board 21 by being soldered to lands 58 (see FIG. 5) formed around the insertion holes 22B, 33B, 42B, and 43B.

FIG. 5 is a schematic diagram showing a part of the circuit board 21. FIG. 6 is a cross-sectional view schematically showing the circuit board 21.
The circuit board 21 is configured by laminating, for example, substrate layers 52A and 52B such as copper foil between a plurality (three in the present embodiment) of insulating layers 51 and on the outer surface. A circuit pattern 53 is formed on each of the substrate layers 52A and 52B, and a conductor wire (conductor) 56 is connected to the inner substrate layer 52A. The insulating layer 51 on the side facing the inner substrate layer 52A is formed with a plurality of recesses 54 at positions corresponding to the conductor wires 56. By stacking the insulating layer 51 and the substrate layer 52A, the recesses 54 are formed. The conductor wire 56 is disposed in the 54. Depending on the thickness of the conductor wire 56, the thickness of the insulating layer 51 in the portion where the concave portion 54 is formed becomes thin. Therefore, the insulating layer 51 may be thickened as necessary. As described above, since the conductor wire 56 is provided in the inner layer of the circuit board 21, the component mounting surface is not used for mounting the conductor wire 56, and the current capacity is increased while suppressing an increase in size of the circuit board 21. be able to.
The soldering lands 58 described above are formed on the substrate layer 52B on the outer surface. The land 58 is electrically connected to the circuit pattern 53 of the other substrate layer 52B, and the electronic components such as the smoothing capacitor 22, the power elements 33UH to 33WL, and the shunt resistor 40 have terminals 22A, 33A, 42, and 43 on the land 58. By being soldered, it is electrically connected to the circuit pattern 53 of the other substrate layer 52B.

  The conductor wire 56 is a thin foil-like conductor that increases the current capacity of the circuit pattern 53, and is configured using, for example, a copper thin plate-like wire. In FIG. 5, the conductor wire 56 and the land 58 are shown on the same plane and the pattern of the conductor wire 56 is shown by shading for the sake of explanation. 5 illustrates the arrangement configuration of the conductor wire 56 related to the shunt resistor 40 arranged on the downstream side of the power element 33UL, the conductor related to the shunt resistor 40 arranged on the downstream side of the power elements 33VL and 33WL. Since the wire 56 has substantially the same configuration, the description thereof is omitted. Furthermore, the conductor wires 56 that increase the capacity of the current flowing from each power element 33UL to the shunt resistor 40 are labeled with the conductor wires 56A to 56D to distinguish them.

  As shown in FIG. 5, the conductor wires 56 </ b> A to 56 </ b> D are arranged in parallel with the arrangement direction of the power elements 33 UL (the longitudinal direction of the circuit board 21). As described above, the power elements 33UH to 33WL are vertically disposed along the longitudinal direction of the circuit board 21, and the shunt resistor 40 is disposed substantially at right angles to the power elements 33UL to 33WL. By arranging the elements 33UL to 33WL in parallel with the arrangement direction of the elements, a circuit can be configured with a minimum component mounting area, and thus the circuit board 21 can be reduced in size.

  In addition, since the shunt resistor 40 is provided with a plurality of pairs of the input terminal 42 and the output terminal 43, the conductor wires 56A to 56D can be linearly provided from the power elements 33UL to the shunt resistor 40. As a result, the resistance between each power element 33UL and the input terminal 42 of the shunt resistor 40 can be made substantially equal as compared with the case where any of the conductor wires 56A to 56D is arranged in a curved line or a broken line. The current density entering the resistor 40 can be equalized, and the current can be detected accurately.

  As shown in FIG. 6, the conductor wire 56 is electrically connected to the substrate layer 52 </ b> A through the connection point 60. The connection point 60 is a conductor portion in which the circuit pattern 53 and the conductor wire 56 are electrically connected, for example, by welding at a portion where the circuit pattern 53 and the conductor wire 56 overlap each other.

By the way, referring to FIG. 5, when the distance between the junction points P of the currents flowing out from the plurality of output terminals 43 is different, the shunt resistor 40 has a difference in the current density of the current flowing out from each output terminal 43. . More specifically, the longer the distance from the output terminal 43 to the merge point P, the less the current flows.
Therefore, in the present embodiment, a connection point 60A is provided near the terminal far from the merge point P (in the vicinity of the two insertion holes 42B1 far from the merge point P in the example of FIG. 5), and the conductor wire 56 is connected. Yes. Thus, since the connection point 60 is provided at a position where the current density of the current flowing out from the output terminal 43 of the shunt resistor 40 is equal, an increase in the apparent resistance value of the shunt resistor 40 can be prevented.

  As described above, according to the present embodiment, the shunt resistor 40 is provided with a plurality of pairs of the input terminal 42 and the output terminal 43 connected to the circuit pattern 53, and flows into each input terminal 42 of the shunt resistor 40. The conductor wire 56 is connected to a position where the current density of the current flowing out from the output terminals 43 is equalized. Since the shunt resistor 40 is provided with a plurality of pairs of the input terminal 42 and the output terminal 43, for example, even when the shunt resistor 40 is connected to a plurality of circuit components (33UL to 33WL) connected in parallel, the conductor wire 56 is straight. Therefore, it is possible to prevent the current flowing through the plurality of input terminals 42 and output terminals 43 from being unbalanced. Further, the shunt resistor 40 has a large resistance value if the current density is not uniform, but the position where the current density flowing into each input terminal 42 of the shunt resistor 40 or the current density flowing out from each output terminal 43 is made equal. Since the conductor wire 56 is connected to the shunt resistor 40, an increase in the apparent resistance value of the shunt resistor 40 can be prevented.

  Further, according to the present embodiment, the shunt resistor 40 has a current path from the input terminal 42 to the output terminal 43 above the circuit pattern 53 (component mounting surface), so that the mounting area of the shunt resistor 40 is reduced. Therefore, the circuit board 21 can be reduced in size.

However, the above embodiment is an aspect of the present invention, and it is needless to say that the embodiment can be appropriately changed without departing from the gist of the present invention.
For example, in the above embodiment, the through hole 61 is formed in the circuit board 21, and the connection point 60 for connecting the circuit pattern 53 and the conductor wire 56 is formed using the through hole 61. If the conductor wire 56 is connected, it is not always necessary to penetrate the circuit board 21. Although the circuit pattern 53 and the conductor wire 56 are connected by welding, the connection between the circuit pattern 53 and the conductor wire 56 is not limited to this.

  In the above embodiment, the conductor wire 56 is welded to the substrate layer 52A. However, the substrate layers 52A and 52B on which the circuit pattern 53 is formed and the conductor layer on which the pattern of the conductor wire 56 is formed are laminated. It is good also as composition to do. With this configuration, since the conductor wires 56 can be provided on the circuit board 21 by laminating the substrate layers 52A and 52B and the conductor layers, the circuit board 21 can be compared with the case where the conductor wires 56 are individually attached to the circuit board 21. Can be easily formed.

DESCRIPTION OF SYMBOLS 1 Motor drive device 20 Power drive unit 21 Circuit board 40 Shunt resistor 42 Input terminal 43 Output terminal 53 Circuit pattern 56 Conductor wire (conductor)

Claims (2)

In a circuit board provided with a conductor that increases the current capacity of the circuit pattern, and a shunt resistor for current detection is connected to the circuit pattern,
The shunt resistor is provided with a plurality of pairs of input terminals and output terminals connected to the circuit pattern, and the current density flowing into each input terminal of the shunt resistor or the current density flowing out from each output terminal is equal. A circuit board characterized in that the conductor is connected to a position to be operated.   The circuit board according to claim 1, wherein the shunt resistor has a current path from the input terminal to the output terminal above the circuit pattern.

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