JP6830214B2 - Power converter - Google Patents

Description

This disclosure relates to a power converter.

For example, the power conversion device disclosed in Patent Document 1 has a converter unit that converts alternating current into direct current with a switch element, a smoothing capacitor unit that smoothes direct current converted by the converter unit, and a smoothed direct current that is converted to alternating current by a switch element. It has an inverter unit for conversion. The smoothing capacitor section is composed of a converter-side smoothing capacitor, an inverter-side smoothing capacitor, and a central-side smoothing capacitor sandwiched between the converter-side capacitor and the inverter-side capacitor. The center side smoothing capacitor is an electrolytic capacitor, and the converter side smoothing capacitor and the inverter side smoothing capacitor are a film capacitor or a ceramic capacitor. That is, the smoothing capacitor section has two types of capacitors.

JP-A-2017-143647

The two types of capacitors in Patent Document 1 are supported by film capacitors as a countermeasure against ripples, and electrolytic capacitors are used to absorb regenerative energy and suppress voltage fluctuations. In addition, the surge was dealt with by a snubber.

However, when a large current is passed through the power converter, for example, when the switch element is switched at a frequency of 5 to 20 kHz, high-order harmonic noise caused by the switching of the large current is radiated to the outside as electromagnetic noise. However, in order to absorb this high frequency noise, it is necessary to separately install a large filter circuit on the power supply line, for example, near the connector. Therefore, there is a problem that the power conversion device becomes large due to both the capacitor and the filter for smoothing.

An object of the present disclosure is to provide a power conversion device capable of miniaturization.

The power conversion device according to this disclosure includes a substrate, a plurality of switch elements provided on the substrate, and a first capacitor electrically connected in parallel between a positive electrode and a negative electrode on the DC voltage side of the switch element. It includes a second capacitor and a third capacitor, the first capacitor is connected to a position closer to the switch element on the wiring path than the second capacitor and the third capacitor, and the third capacitor is compared with the second capacitor. The first capacitor is connected to a position far from the switch element on the wiring path, and the first capacitor has a smaller impedance in the frequency band from high frequency noise to surge that leads to electromagnetic interference than the second and third capacitors. , The impedance in the ripple frequency band is smaller than that of the first capacitor and the third capacitor, and the third capacitor has a smaller impedance in the frequency band lower than the ripple frequency band as compared with the first capacitor and the second capacitor.

The power conversion device according to one aspect of the present disclosure can be miniaturized.

FIG. 1 is a diagram illustrating an electric vehicle including the vehicle drive device according to the first embodiment. FIG. 2 is a circuit diagram of the vehicle drive device according to the first embodiment. FIG. 3 is a schematic correlation diagram of the capacitance per unit volume and the applicable frequency of each capacitor according to the first embodiment. FIG. 4 is a frequency characteristic diagram of the impedance of each capacitor according to the first embodiment. FIG. 5 is a plan view showing the layout of each switch element and each capacitor according to the first embodiment. FIG. 6 is a plan view showing the layout of each switch element and each capacitor according to the first modification. FIG. 7 is a perspective view showing a schematic configuration of the three-phase inverter circuit according to the second modification. FIG. 8 is a plan view showing a module according to the second modification. FIG. 9 is a plan view showing the layout of each switch element and each capacitor according to the modified example 3. FIG. 10 is a plan view showing a configuration in the vicinity of the switch element according to the third modification. FIG. 11 is a plan view showing the layout of each switch element and each capacitor according to the modified example 4. FIG. 12 is a plan view showing the layout of each switch element and each capacitor according to the modified example 5. FIG. 13 is a side view showing the layout of each switch element and each capacitor according to the modified example 6. FIG. 14 is a plan view showing the substrate according to the modified example 7. FIG. 15 is a plan view showing a schematic configuration of the three-phase inverter circuit according to the second embodiment. FIG. 16 is a perspective view showing an electrical connection structure according to the second embodiment. FIG. 17 is a cross-sectional view of the bus bar according to the second embodiment. FIG. 18 is a side view of the bus bar according to the second embodiment. FIG. 19 is a perspective view showing an electrical connection structure according to the third embodiment. FIG. 20 is a cross-sectional view of the bus bar 130 according to the third embodiment. FIG. 21 is a side view of the bus bar 130 according to the third embodiment. FIG. 22 is a plan view showing another layout of each switch element and each capacitor according to the first embodiment. FIG. 23 is a plan view showing another schematic configuration of the three-phase inverter circuit according to the second embodiment.

The power conversion device according to one aspect of the present disclosure is electrically connected in parallel between a substrate, a plurality of switch elements provided on the substrate, and a positive electrode and a negative electrode on the DC voltage side of the switch element, respectively. It includes one capacitor, a second capacitor and a third capacitor, the first capacitor is connected at a position closer to the switch element on the wiring path than the second capacitor and the third capacitor, and the third capacitor is the second capacitor. It is connected to a position farther from the switch element on the wiring path than the capacitor, the first capacitor has a smaller impedance in the frequency band from electromagnetic interference to surge than the second capacitor and the third capacitor, and the second capacitor has a smaller impedance. The impedance in the ripple frequency band is smaller than that of the first capacitor and the third capacitor, and the third capacitor has a smaller impedance in the frequency band lower than the ripple frequency band as compared with the first capacitor and the second capacitor.

According to this configuration, the first capacitor has a smaller impedance in the frequency band from high frequency noise to surge that leads to electromagnetic interference (hereinafter referred to as EMI) than other capacitors, and is a switch on the wiring path. It is located close to the element, and the parasitic inductance caused by the wiring path is small. As a result, the first capacitor closest to the switch element can suppress high frequency noise and surge in a high frequency band ranging from high frequency noise of several hundred MHz to surge of several MHz order, for example. In addition, the third capacitor farthest from the switch element has the smallest impedance compared to other capacitors in the frequency band (for example, up to several hundred Hz) in the pulsating current and abnormal current, which is lower than the ripple frequency band. While suppressing self-heating in this frequency band, it is possible to absorb and smooth a pulsating current that is significantly lower than surge or ripple, or to absorb an abnormal current. The third capacitor is arranged at a position farther from the switch element on the wiring path than the other capacitors, and the parasitic inductance caused by the wiring path becomes large. As a result, the ripple current in the ripple frequency band to the third capacitor is suppressed, so that the self-heating of the third capacitor due to the ripple current can also be suppressed. Further, since the impedance of the second capacitor arranged in the middle of the other capacitors on the wiring path is smaller than that of the other capacitors in the ripple frequency band (for example, 5 to 20 kHz), self-heating due to the ripple can be suppressed. .. The parasitic inductance of the second capacitor in the wiring path is an intermediate size between the first capacitor and the third capacitor, but since this parasitic inductance and the second capacitor act as a filter for transmitting the ripple current, the first capacitor It is possible to optimize self-heating in the second capacitor and the third capacitor.

In this way, by providing the first capacitor, the second capacitor, and the third capacitor suitable for each role, each capacitor can be made to have an appropriate size, as compared with the conventional case where each role is played by two types of capacitors (capacitors). It can be set to the number. Therefore, since the first capacitor suppresses high-frequency noise and surge, it is not necessary to separately provide a large filter circuit for EMI countermeasures, and the size can be reduced accordingly. Further, by determining the combination of the size and the number of each capacitor that minimizes the total volume of the first capacitor, the second capacitor, and the third capacitor, it is possible to reduce the size of the entire power conversion device.

Here, since the third capacitor has a larger impedance in each used frequency band than the other capacitors, the self-heating is also relatively large. Therefore, it is arranged at the farthest position on the wiring path. As a result, since the third capacitor is arranged away from the switch element which is a heat source, the possibility of receiving heat from the switch element in addition to self-heating is reduced. In addition, the third capacitor has a larger capacity than other capacitors, so its size is also large, but if it is located far from the switch element, the degree of freedom in space is high, and the third capacitor is placed at an appropriate position. It will be easier to place.

Further, the wiring path between the second capacitor and the third capacitor is configured to suppress the transmission of the ripple current in the ripple frequency band.

According to this configuration, it is possible to configure a filter that suppresses the ripple current to the third capacitor by utilizing the parasitic inductance of the wiring path from the second capacitor to the third capacitor. As a result, the third capacitor suppresses self-heating due to the ripple current, so that the third capacitor, which has been enlarged for the purpose of heat resistance, can be downsized.

Further, the wiring path between the second capacitor and the third capacitor is composed of a bus bar.

According to this configuration, the parasitic inductance of the wiring path can be adjusted by at least one of the shape, size and material of the bus bar, and the frequency characteristic of the filter composed of the parasitic inductance of the second capacitor, the third capacitor, and the bus bar. Is easy to match with the frequency band of the ripple.

Further, the bus bar is configured to suppress the transmission of the ripple current by adjusting at least one of the shape, size and material.

According to this, since the bus bar is configured to suppress the transmission of the ripple current by adjusting at least one of the shape, size and material of the bus bar, the transmission of the ripple current can be suppressed more reliably. Can be done.

Further, an inductor is electrically connected to the wiring path.

According to this, since the inductor is electrically connected to the wiring path, the inductance value of the combined inductor of the inductance value of the wiring path and the inductance value of the inductor is adjusted by adjusting the inductance value of the inductor. be able to. By adjusting the inductance value of the composite inductor, it is possible to suppress the transmission of ripple current.

The first capacitor is a ceramic capacitor, the second capacitor is a hybrid capacitor, and the third capacitor is an electrolytic capacitor.

According to this configuration, since the ceramic capacitor is the first capacitor, it is possible to effectively suppress high frequency noise and surge in the high frequency band in the above frequency band. Further, since the hybrid capacitor is the second capacitor, the ripple generated by the switching control of the motor can be effectively suppressed. Further, since the hybrid capacitor has a larger capacity per unit volume than the film capacitor, the volume for obtaining the capacity required for suppressing ripple is smaller than that of the film capacitor, and the size can be reduced. Further, even when an electrolytic capacitor having a relatively large amount of self-heating is used as the third capacitor, since it is located at the position farthest from the switch element which is a heat source on the wiring path, the switch element with respect to the electrolytic capacitor It can be less affected by the heat from. Furthermore, since the parasitic inductance in the wiring path is large, self-heating due to the ripple current is suppressed, and in the above-mentioned frequency band, suppression of low-frequency pulsating current and current absorption at the time of abnormality are effective. It can be realized.

Further, the plurality of the switch elements form a three-phase inverter circuit, and the plurality of the switch elements are a U-phase high-side switch element, a U-phase low-side switch element, a V-phase high-side switch element, and a V-phase low-side. The U-phase low-side switch element, which includes a switch element, a W-phase high-side switch element, and a W-phase low-side switch element, is arranged with respect to the first side of a virtual regular hexagon that fits within the substrate, and is a U-phase. The high-side switch element is arranged on the second side adjacent to the first side of the regular hexagon, and the V-phase low-side switch element is arranged on the third side adjacent to the second side of the regular hexagon. The V-phase high-side switch element is arranged with respect to the fourth side adjacent to the third side of the regular hexagon, and the W-phase low-side switch element is arranged with respect to the fifth side adjacent to the fourth side of the regular hexagon. The W-phase high-side switch element is arranged with respect to the sixth side adjacent to the fifth side of the regular hexagon.

According to this configuration, the high-side switch element and the low-side switch element of each phase are arranged on each side of the virtual regular hexagon that fits in the substrate, so that each switch element can be arranged evenly. it can. Therefore, the power conversion device can be made smaller.

Further, the third capacitor is arranged in the central portion of the substrate, and the first capacitor and the second capacitor are arranged in the outer peripheral portion of the substrate rather than the third capacitor.

According to this configuration, since the first capacitor and the second capacitor are arranged on the outer peripheral portion of the substrate and the third capacitor is arranged on the central portion of the substrate, the area is easily secured with respect to the central portion of the substrate. A third capacitor, which is larger than other capacitors, can be arranged. As a result, the area on the surface of the substrate can be effectively utilized.

Further, it has a first substrate, a second substrate and a third substrate separate from the substrate, the plurality of switch elements form a three-phase capacitor circuit, and the plurality of switch elements are U-phase high-side switch elements, U. A phase low-side switch element, a V-phase high-side switch element, a V-phase low-side switch element, a W-phase high-side switch element, and a W-phase low-side switch element are included. An element, a U-phase low-side switch element, and a first capacitor and a second capacitor electrically connected to the U-phase high-side switch element and the U-phase low-side switch element are provided, and a second substrate is provided. The V-phase high-side switch element, the V-phase low-side switch element, and the first capacitor and the second capacitor electrically connected to the V-phase high-side switch element and the V-phase low-side switch element. Is provided, and the third substrate is electrically connected to a W-phase high-side switch element, a W-phase low-side switch element, the W-phase high-side switch element, and a W-phase low-side switch element. A first capacitor and a second capacitor are provided, and a third capacitor is provided on the substrate, and a first substrate, a second substrate, and a third substrate are erected so as to surround the third capacitor. Has been done.

According to this configuration, the first substrate, the U-phase high-side switch element, the U-phase low-side switch element, the first capacitor, and the second capacitor are modularized. Similarly, the second substrate, the V-phase high-side switch element, the V-phase low-side switch element, the first capacitor, and the second capacitor are modularized. Further, the third substrate, the W-phase high-side switch element, the W-phase low-side switch element, the first capacitor and the second capacitor are modularized. Since each of these modules is erected with respect to the substrate so as to surround the third capacitor, the size can be reduced in the plan view of the substrate.

Further, the sizes of the first substrate, the second substrate and the third substrate are substantially the same.

According to this configuration, since the sizes of the first substrate, the second substrate, and the third substrate are substantially the same, each module can be made substantially the same size, and as a result, the power conversion device can be made smaller. Can be.

Further, the switch element and the first capacitor are provided on the first substrate, and the second capacitor and the third capacitor are provided on the second substrate facing the first substrate.

According to this configuration, the first substrate provided with the switch element and the first capacitor and the second substrate provided with the second capacitor and the third capacitor are arranged so as to face each other. The substrate and the second substrate overlap in a plan view. Therefore, the power conversion device can be made smaller.

Further, the plurality of switch elements are arranged along a virtual circle that fits in the substrate.

According to this, since a plurality of switch elements are arranged along a virtual circle that fits in the substrate, each switch element can be evenly arranged. Therefore, the power conversion device can be made smaller.

Further, the plurality of switch elements form a three-phase inverter circuit for driving the motor, and the substrate is arranged parallel to the plane orthogonal to the rotation axis of the motor and on the end face side of the motor.

According to this, since the substrate is arranged parallel to the end surface side of the motor in a plane orthogonal to the rotation axis of the motor, the substrate and the motor overlap in the axial direction. Therefore, the substrate and the motor can be arranged compactly, and the power conversion device can be made smaller.

Further, the bus bar is electrically connected to the first bus bar having a first connecting portion electrically connected to the substrate and a first standing portion erected from one end of the first connecting portion, and an electric bus bar to the substrate. A second bus bar having a second connecting portion to be specifically connected and a second standing portion erected from one end of the second connecting portion, and the first standing portion and the second standing portion are insulated from each other. It is provided with an insulating portion for holding the first bus bar and the second bus bar so as to face each other at a predetermined distance in the state, and one of the first bus bar and the second bus bar is electrically connected to the positive electrode of the DC power supply. , The other of the first bus bar and the second bus bar is electrically connected to the negative electrode of the DC power supply.

According to this, one of the first bus bar and the second bus bar is electrically connected to the positive electrode of the DC power supply, and the other of the first bus bar and the second bus bar is electrically connected to the negative electrode of the DC power supply. Therefore, the magnetic field caused by the current flowing through the first standing portion of the first bus bar and the magnetic field caused by the current flowing through the second standing portion of the second bus bar are in opposite directions. Since the first erection part and the second erection part face each other with a predetermined interval via the insulating part, the magnetic field generated in the first erection part and the second erection part The generated magnetic fields cancel each other out, and as a result, the inductance can be reduced. Therefore, in addition to high-density mounting by three-dimensional arrangement between substrates, it is possible to provide an electrical connection member capable of reducing inductance.

Further, one of the first connection portion and the second connection portion is connected to the conductive pattern on the positive electrode side provided on the substrate by soldering, and the other of the first connection portion and the second connection portion is on the substrate. It is connected to the conductive pattern on the negative electrode side provided in the above by soldering.

According to this, since both the first connection portion and the second connection portion are connected to the conductive pattern on the substrate by soldering, the first connection portion and the second connection portion are connected to the substrate. It is possible to easily connect to the above conductive pattern. Since both the first connection portion and the second connection portion are soldered to the conductive pattern without passing through the through holes, the connection area can be increased and the connection strength can also be increased.

The substrate is a metal substrate.

According to this, since the substrate is a metal substrate, the heat generated by the electrical connection member can be efficiently dissipated through the metal substrate.

Further, at least one convex portion is formed on one of the intermediate portion between the first connection portion and the second connection portion and the substrate in the insulating portion, and the intermediate portion and the other of the substrate have at least one convex portion. Is formed with at least one recess into which at least one convex is individually fitted.

According to this, since the convex portion provided on one of the intermediate portion and the substrate is fitted to the concave portion provided on the other side of the intermediate portion and the substrate, before the work of connecting to the conductive pattern Even if there is, the electrical connection member and the substrate can be stably held. Therefore, during the connection work, the electrical connection member is less likely to be displaced with respect to the substrate, and the connection work can be easily performed.

Further, at least one of the first capacitor and the second capacitor is held by the insulating portion and is arranged between the first standing portion and the second standing portion, and the first standing portion and the second capacitor are arranged. It is electrically connected to the upright part.

According to this, at least one of the second capacitor and the third capacitor arranged between the first standing part and the second standing part is relative to the first standing part and the second standing part. Since it is electrically connected, the ripple noise of the current flowing through the first bus bar and the second bus bar can be reduced.

Further, at least one of the second capacitor and the third capacitor is provided, and among the second capacitor and the third capacitor, the one provided with a plurality of the second capacitor and the third capacitor is at least one electrically in series, parallel, and series-parallel, respectively. It is connected in the form.

According to this, since the plurality of capacitors (at least one of the second capacitor and the third capacitor) are electrically connected in at least one form of series, parallel, and series-parallel, the plurality of capacitors are provided. The number of installations, the combination, and the connection form can be adjusted, and the desired capacitance value and withstand voltage value can be adjusted.

(Embodiment 1)
Hereinafter, the first embodiment will be specifically described with reference to the drawings. In addition, each of the first embodiment described below shows a comprehensive or concrete example. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, steps, the order of steps, and the like shown in the following embodiments are examples, and are not intended to limit the present invention. In addition, among the components in the following embodiments, the components not described in the independent claims indicating the embodiment according to the present disclosure will be described as arbitrary components. The embodiment of the present disclosure is not limited to the current independent claims, but may be expressed by other independent claims.

Further, each figure is a schematic view and is not necessarily exactly illustrated. Further, in each figure, the same components are designated by the same reference numerals.

Further, expressions indicating relative directions or postures such as parallel and orthogonal include cases where they are not strictly the directions or postures. For example, the fact that two directions are orthogonal not only means that the two directions are completely orthogonal, but also that they are substantially orthogonal, that is, a difference of, for example, about several percent. It also means to include.

[1. Vehicle drive]
First, a vehicle drive device including an inverter, which is a power conversion device according to the first embodiment, will be described.

FIG. 1 is a diagram illustrating an electric vehicle including the vehicle drive device according to the first embodiment. The electric vehicle 1 includes a drive wheel 2, a power transmission mechanism 3, a permanent magnet motor M1, an inverter 10, and a battery P1. Of these configurations, the vehicle drive device 5 is composed of a permanent magnet motor M1, an inverter 10, and a battery P1. Hereinafter, the permanent magnet motor M1 may be referred to as a motor M1.

The motor M1 is a three-phase AC motor that drives the drive wheels 2 of the electric vehicle 1, and for example, a motor such as an embedded magnet synchronous motor or a surface magnet synchronous motor is used.

The power transmission mechanism 3 is composed of, for example, a differential gear and a drive shaft, and transmits power between the motor M1 and the drive wheels 2. The rotational force of the motor M1 is transmitted to the drive wheels 2 via the power transmission mechanism 3. Similarly, the rotational force of the drive wheels 2 is transmitted to the motor M1 via the power transmission mechanism 3. The electric vehicle 1 does not have to include the power transmission mechanism 3, and may have a structure in which the motor M1 and the drive wheels 2 are directly connected.

The battery P1 is a DC power source such as a lithium ion battery. The battery P1 supplies and stores electric power for driving the motor M1.

The inverter 10 is an example of a power conversion device that converts the DC power supplied from the battery P1 into, for example, three-phase AC power, and supplies the AC power to the motor M1. As described above, the vehicle driving device 5 is configured to drive the three-phase AC motor M1 by using the electric power of the battery P1.

FIG. 2 is a circuit diagram of the vehicle drive device according to the first embodiment. The voltage Vp shown in FIG. 2 is the power supply voltage, and the voltage Vg is the ground voltage.

As shown in FIG. 2, the vehicle driving device 5 includes a motor M1, an inverter 10, and a battery P1.

[2. Inverter]
The inverter 10 includes a three-phase inverter circuit 40, a drive circuit 30, and a control circuit 20. The three-phase inverter circuit 40 is a circuit that converts the DC power supplied from the battery P1 into three-phase AC power by a switching operation, supplies the AC power to the motor M1, and drives the motor M1. The input side of the three-phase inverter circuit 40 is connected to the drive circuit 30, and the output side is connected to the motor M1.

Specifically, the three-phase inverter circuit 40 includes switch elements S1, S2, and S3 (high-side switch elements) provided in the upper arm group located on the upper side of FIG. 2, and a lower side located on the lower side of FIG. The switch elements S4, S5, and S6 (low-side switch elements) provided in the side arm group are provided. For example, the switch elements S1 to S6 are composed of a field effect transistor (FET), an insulated gate bipolar transistor (IGBT), or the like. Further, the switch elements S1 to S6 may be configured by using a wide bandgap semiconductor.

The switch elements S1, S2, and S3 are connected between the three output lines drawn from the three terminals of the motor M1 and the power supply line Lp connected to the positive electrode of the battery P1. The switch elements S4, S5, and S6 are connected between the above three output lines and the ground wire Lg connected to the negative electrode of the battery P1. Further, a freewheeling diode is connected in parallel to each of the switch elements S1 to S6. The freewheeling diode may be a parasitic diode parasitic on the switch elements S1 to S6. The switch elements S1 and S4 are electrically connected to the U phase of the motor M1, the switch element S1 is a U phase high side switch element, and the switch element S4 is a U phase low side switch element. The switch elements S2 and S5 are electrically connected to the V phase of the motor M1, the switch element S2 is a V phase high side switch element, and the switch element S5 is a V phase low side switch element. The switch elements S3 and S6 are electrically connected to the W phase of the motor M1, the switch element S3 is a W phase high side switch element, and the switch element S6 is a W phase low side switch element.

The switch elements S1 to S6 are connected to the drive circuit 30 and are driven by the signal output from the drive circuit 30. The motor M1 is driven in a state of power running, regeneration, coasting, or the like based on the driving of the switch elements S1 to S6.

Further, the inverter 10 is provided with a plurality of capacitors for smoothing the voltage applied to the three-phase inverter circuit 40. Here, the plurality of capacitors include a ceramic capacitor C1, a hybrid capacitor C2, and an electrolytic capacitor C3.

The ceramic capacitor C1 is an example of the first capacitor, one terminal is connected to the power supply line Lp, and the other terminal is connected to the ground wire Lg. The hybrid capacitor C2 is an example of a second capacitor, one terminal of which is connected to the power supply line Lp and the other terminal of which is connected to the ground wire Lg. The hybrid capacitor C2 is a capacitor in which a conductive polymer and an electrolytic solution are fused with an electrolyte. The hybrid capacitor C2 may be referred to as, for example, a conductive polymer hybrid aluminum electrolytic capacitor. The electrolytic capacitor C3 is an example of a third capacitor, one terminal of which is connected to the power supply line Lp and the other terminal of which is connected to the ground wire Lg.

As shown in FIG. 2, the ceramic capacitor C1 is connected to the hybrid capacitor C2 at a position closer to the switch elements S1 to S6 than the electrolytic capacitor C3 on the wiring path. Further, the electrolytic capacitor C3 is connected to a position farther from each switch element S1 to S6 on the wiring path than the hybrid capacitor C2. That is, from each switch element S1 to S6, the ceramic capacitor C1, the hybrid capacitor C2, and the electrolytic capacitor C3 are arranged side by side in this order. Therefore, the magnitude of the parasitic inductance in the wiring path increases in the order of the ceramic capacitor C1, the hybrid capacitor C2, and the electrolytic capacitor C3.

Here, the roles of the three types of capacitors of the present embodiment will be described with reference to FIG. FIG. 3 is a schematic correlation diagram of the capacitance per unit volume and the applicable frequency of each capacitor according to the first embodiment. In FIG. 3, the horizontal axis represents the capacity per unit volume, and the vertical axis represents the adaptive frequency (logarithm).

The roles of smoothing capacitors in power converters such as automobile drive inverters are (1) EMI countermeasures, (2) surge suppression to protect the withstand voltage of semiconductors that make up switch elements, and (3) stability of the DC system. There are ripple current suppression for conversion, (4) pulsating current and current absorption at the time of abnormality. Regarding the EMI countermeasure of (1), when a large current is passed through the inverter 10, for example, when the switch elements S1 to S6 are switched at a frequency of 5 to 20 kHz, high-order harmonic noise caused by the switching of the large current is generated. It is radiated to the outside as electromagnetic noise (high frequency noise), but its frequency is, for example, a maximum of several 100 MHz. Therefore, as a smoothing capacitor, high frequency characteristics on the order of several hundred MHz are required. In this case, less capacity is needed. The surge suppression of (2) is to suppress a surge of several MHz order, which is generated based on the parasitic inductance and current on the circuit when the switch elements S1 to S6 are switched at a frequency of, for example, 5 to 20 kHz. In addition, a smoothing capacitor with low impedance in the surge frequency band is required. In this case, a capacity is required more than the EMI countermeasure of (1), but a large capacity is not required.

On the other hand, the current absorption in (4), especially at the time of abnormality, is the place where the regenerative current goes when the relay of the battery is opened due to some trouble in the situation where the battery is being charged by the regenerative brake, for example. It will disappear and all will be charged to the smoothing capacitor. Therefore, the voltage of the smoothing capacitor rises sharply. At this time, even if the regeneration is stopped by the instruction of the control circuit of the inverter, the current stored in the motor winding remains, so a smoothing capacitor having a sufficient capacity is required to absorb the current. However, since this operation is slow, for example, several tens to several hundred milliseconds, the frequency band is, for example, several hundred Hz, and a capacitor having excellent high frequency characteristics is not required.

In addition, the ripple suppression in (3) has intermediate capacitance and frequency characteristics (for example) with respect to the EMI countermeasures in (1), the surge suppression in (2), and the pulsating current and current absorption in the event of an abnormality in (4). A smoothing capacitor of 5 to 20 kHz) is required.

From these facts, it can be seen that the ceramic capacitor C1 can be applied to the EMI countermeasure of (1) and the surge suppression of (2) with reference to FIG. Further, a film capacitor or a hybrid capacitor C2 can be applied to suppress the ripple in (3), but miniaturization can be achieved by applying a hybrid capacitor C2 having a large capacity per unit volume. It can be seen that the electrolytic capacitor C3 can be applied to the pulsating current of (4) and the current absorption at the time of abnormality.

Next, the frequency characteristics of the ceramic capacitor C1, the hybrid capacitor C2, and the electrolytic capacitor C3 will be described in more detail. FIG. 4 is a frequency characteristic diagram of the impedance of each capacitor (ceramic capacitor C1, hybrid capacitor C2, electrolytic capacitor C3) according to the first embodiment. In FIG. 4, the horizontal axis is frequency (logarithm) and the vertical axis is impedance. From FIG. 4, the ceramic capacitor C1 has a lower impedance than the hybrid capacitor C2 and the electrolytic capacitor C3 in the frequency band of high frequency noise and surge connected to EMI (for example, from several MHz order to several hundred MHz). The hybrid capacitor C2 has a lower impedance than the ceramic capacitor C1 and the electrolytic capacitor C3 in the ripple frequency band (for example, 5 to 20 kHz). The electrolytic capacitor C3 has a lower impedance than the ceramic capacitor C1 and the hybrid capacitor C2 in a frequency band lower than the ripple, that is, a frequency band of a pulsating current or a current generated from the motor M1 at the time of abnormality (for example, several hundred Hz). Therefore, by using the capacitor having the lowest impedance in the frequency band described above, it is possible to realize a smoothing function in which self-heating is suppressed in each frequency band.

Further, the impedance in the frequency band used of each capacitor (the region surrounded by the ellipse in FIG. 4) is larger in the order of the ceramic capacitor C1, the hybrid capacitor C2, and the electrolytic capacitor C3. Therefore, the electrolytic capacitor C3 has the largest self-heating as compared with other capacitors.

Based on these characteristics, each capacitor can be applied as follows.

The ceramic capacitor C1 (first capacitor) has a smaller impedance in the surge frequency band than the hybrid capacitor C2 and the electrolytic capacitor C3, and is arranged at a position closer to the switch element on the wiring path. The parasitic inductance caused by is also small. As a result, the ceramic capacitor C1 closest to the switch elements S1 to S6 can be applied to smoothing the high frequency band, and for example, high frequency noise of several hundred MHz and surge of several MHz order can be suppressed.

The electrolytic capacitor C3 (third capacitor) farthest from the switch elements S1 to S6 is a hybrid with the ceramic capacitor C1 in the frequency band (for example, up to several hundred Hz) in the pulsating current or the abnormal current, which is lower than the frequency band of the ripple. Since it has the smallest impedance compared to the capacitor C2, it smoothes pulsating currents that are significantly lower than high-frequency noise, surges, or ripples, and absorbs abnormal currents while suppressing self-heating in this frequency band. be able to. The electrolytic capacitor C3 is arranged at a position farther from the switch elements S1 to S6 on the wiring path than the ceramic capacitor C1 and the hybrid capacitor C2, and the parasitic inductance caused by the wiring path is large. As a result, the ripple current in the ripple frequency band is suppressed, so that the self-heating of the third capacitor due to the ripple current can also be suppressed. Further, since the electrolytic capacitor C3 has a larger impedance in each used frequency band than the ceramic capacitor C1 and the hybrid capacitor C2, the self-heating is also relatively large. Therefore, it is arranged at the farthest position on the wiring path. As a result, since the electrolytic capacitor C3 is arranged away from the switch elements S1 to S6 which are heat sources, the possibility of receiving heat from the switch elements S1 to S6 in addition to self-heating is reduced. ..

Further, the hybrid capacitor C2 (second capacitor) arranged between the ceramic capacitor C1 and the electrolytic capacitor C3 on the wiring path has an impedance in the ripple frequency band (for example, 5 to 20 kHz) of the ceramic capacitor C1 and the electrolytic capacitor C3. Since it is smaller, self-heating due to ripple can be suppressed. The parasitic inductance of the hybrid capacitor C2 in the wiring path is an intermediate size between the ceramic capacitor C1 and the electrolytic capacitor C3. Since the parasitic inductance and the hybrid capacitor C2 act as a filter for transmitting the ripple current, the hybrid capacitor C2 is hybrid. It is possible to optimize the self-heating of the capacitor C2 and the electrolytic capacitor C3.

An example of the combination in which the total volume of each capacitor is minimized according to the role of each capacitor and the capacity and size described above is shown below. Since the ceramic capacitor C1 has a small capacitance, its size is also extremely small as compared with the hybrid capacitor C2 and the electrolytic capacitor C3, so that it is ignored when calculating the total volume. Therefore, here, an example of minimizing the total volume of the hybrid capacitor C2 and the electrolytic capacitor C3 will be described.

First, regarding the size, it is assumed that the volume ratio of the hybrid capacitor C2 and the electrolytic capacitor C3 is 1: 5. That is, one electrolytic capacitor C3 has five times the volume of one hybrid capacitor C2. Next, it is assumed that the total required capacitance value of the hybrid capacitor C2 and the electrolytic capacitor C3 is constant.

Under this condition, the number of the hybrid capacitor C2 and the electrolytic capacitor C3 was varied, and the number of combinations having the minimum volume was obtained. As a result, the volume of the hybrid capacitor C2 and the electrolytic capacitor C3 became the minimum when the number ratio was 1: 3. A specific example configured with this ratio will be described later with reference to FIG. In addition, as a result of finding the volume for obtaining the required capacitance value only with the electrolytic capacitor C3, ignoring the ceramic capacitor, as a result of comparing with the case of being composed of two types of capacitors (electrolytic capacitor and ceramic capacitor) as in the conventional case, the above It was about twice the volume when the number ratio of the hybrid capacitor C2 and the electrolytic capacitor C3 was 1: 3. Therefore, the smoothing capacitor can be reduced to half the volume of the conventional one.

In this way, by particularly selecting the combination of the hybrid capacitor C2 and the electrolytic capacitor C3, the volume of the entire smoothing capacitor can be minimized, and the power conversion device can be miniaturized. Specific examples of the layout of each switch element S1 to S6 and each capacitor will be described later.

Further, the above result is an example, and since there are various sizes and capacities of each capacitor, the optimum number of combinations may be appropriately obtained according to each capacitor to be used.

Here, returning to FIG. 2, the drive circuit 30 is a circuit that drives the switch elements S1 to S6 of the three-phase inverter circuit 40 in order to execute the three-phase PWM control. The input side of the drive circuit 30 is connected to the control circuit 20, and the output side is connected to the three-phase inverter circuit 40. The drive circuit 30 may drive the switch elements S1 to S6 of the three-phase inverter circuit 40 in order to execute the three-phase short-circuit control.

The control circuit 20 is composed of a microprocessor that performs various operations and the like, and a memory that stores a program or information for operating the microprocessor.

The control circuit 20 acquires information detected by various sensors such as current sensors CSu, CSv, CSw that detect the current flowing through the motor M1 and a rotation position sensor RS that detects the magnetic pole position of the motor M1 and detects the rotation position. To do. The current sensors CSu, CSV, and CSw are sensors that detect current values in the U phase, V phase, and W phase of the motor M1. Further, the control circuit 20 acquires information regarding the voltage Vp in the power supply line Lp. Further, the control circuit 20 acquires control command information such as a torque command output from the outside of the control circuit 20, for example, the ECU (Engine Control Unit) of the electric vehicle 1.

The control circuit 20 converts the acquired information by calculation to obtain a control signal for controlling the motor M1. For example, in the control circuit 20, the torque of the motor M1 during operation of the vehicle drive device 5 becomes a target torque (for example, a torque corresponding to the operation amount of the accelerator pedal of the electric vehicle 1) indicated in the torque command information. Obtain the control signal. The control circuit 20 calculates a drive signal required to drive the motor M1 based on the obtained control signal, and outputs this drive signal to the drive circuit 30. The control circuit 20 outputs a drive signal for performing three-phase PWM control when the vehicle drive device 5 is normally operating.

In this way, the control circuit 20 outputs a drive signal for executing the three-phase PWM control to the drive circuit 30. In the drive circuit 30, the drive signal output from the control circuit 20 is output to the three-phase inverter circuit 40. The three-phase inverter circuit 40 drives the motor M1 based on the signal output from the drive circuit 30.

[3. Layout of each switch element and each capacitor]
Next, the layout of each switch element S1 to S6 and each capacitor will be described. FIG. 5 is a plan view showing the layout of each switch element and each capacitor according to the first embodiment.

As shown in FIG. 5, the three-phase inverter circuit 40 has, for example, a regular hexagonal substrate 80, and for this substrate 80, each switch element S1 to S6 and each capacitor (ceramic capacitor C1 and hybrid capacitor) C2) is provided.

Specifically, on one main surface of the substrate 80, a first conductive pattern 81, a second conductive pattern 82, a U-phase conductive pattern 83, a V-phase conductive pattern 84, and a W-phase conductive pattern 85 are formed. It is provided. The first conductive pattern 81 is a conductive pattern on the positive electrode side, and has a regular hexagonal outer shape. The first bus bar 71 connected to the power supply line Lp is electrically connected to the first conductive pattern 81 from the other main surface side of the substrate 80. An opening 811 is provided inside the first conductive pattern 81. The opening 811 has a central opening 812 located at the center of the substrate 80, and three overhangs 813, 814, and 815 protruding from the central opening 812.

A second conductive pattern 82 is arranged in the central opening 812. The second conductive pattern 82 is a conductive pattern on the negative electrode side, and is formed in a shape that does not come into contact with the first conductive pattern 81. A second bus bar 72 connected to the ground wire Lg is electrically connected to the second conductive pattern 82 from the other main surface side of the substrate 80. An electrolytic capacitor C3 is electrically connected to the first bus bar 71 and the second bus bar 72 at a position outside the substrate 80.

Here, the first bus bar 71 and the second bus bar 72 will be described. In the present embodiment, the wiring path between the hybrid capacitor C2 (second capacitor) and the electrolytic capacitor C3 (third capacitor) is configured to suppress the transmission of the ripple current in the ripple frequency band described above. doing. Specifically, the first bus bar 71 and the second bus bar 72 are used as the wiring route. Then, from the capacitance values of the hybrid capacitor C2 and the electrolytic capacitor C3 and the frequency band of the ripple, the first bus bar 71 has a value such that the parasitic inductance of the first bus bar 71 and the second bus bar 72 functions as a filter. And at least one of the shape, size, and material of the second bus bar 72 is determined. The shape is flat in the configuration of FIG. 5, but is not limited to this, and the value of the parasitic inductance can be set by making the longitudinal cross-sectional shape of each bus bar U-shaped or U-shaped. It may be adjusted in the direction of increasing. It is also possible to adjust the length as the shape of the bus bar. Generally, a bus bar is required to connect objects to each other at the shortest distance, but it is also possible to increase the value of the parasitic inductance by making the length of the bus bar longer than the shortest distance. As for the size, a desired parasitic inductance can be obtained depending on the length, width, and thickness of each bus bar. Further, as the material, an appropriate material may be selected from conductive materials having different resistance values. Examples of the conductive material that can be a bus bar include aluminum, copper, iron, brass, and alloys thereof. In this way, the parasitic inductance can be easily adjusted by adjusting at least one of the shape, size, and material of each bus bar.

By determining the shapes and sizes of the first bus bar 71 and the second bus bar 72 in this way, the ripple current to the electrolytic capacitor C3 is utilized by utilizing the parasitic inductance of the wiring path from the hybrid capacitor C2 to the electrolytic capacitor C3. It constitutes a filter that suppresses. As a result, the electrolytic capacitor C3 suppresses self-heating caused by the ripple current, so that the electrolytic capacitor C3, which has been enlarged for the purpose of heat resistance, can be downsized.

In the present embodiment, the wiring path from the hybrid capacitor C2 to the electrolytic capacitor C3 is configured by a bus bar, but the wiring path is not limited to that, and the pattern shape and length of the first conductive pattern 81 and the second conductive pattern 82 are not limited thereto. Thereby, the parasitic inductance may be adjusted. However, since the first conductive pattern 81 and the second conductive pattern 82 are formed on a flat surface, the patterns become long in order to obtain a desired parasitic inductance. In order to reduce the size of the power conversion device, it is desirable to apply a bus bar capable of three-dimensional wiring to the wiring path.

Each of the three overhanging portions 813, 814, and 815 extends along a virtual regular hexagon H arranged in the main surface of the substrate 80. The virtual regular hexagon H is preferably concentric with the substrate 80. Each side of the virtual regular hexagon H is defined as a first side h1, a second side h2, a third side h3, a fourth side h4, a fifth side h5, and a sixth side h6. In FIG. 5, the second side h2, the third side h3, the fourth side h4, the fifth side h5, and the sixth side h6 are arranged counterclockwise in this order with respect to the first side h1. ..

A U-phase conductive pattern 83 is arranged in the overhanging portion 813. The U-phase conductive pattern 83 is electrically connected to the U-phase of the motor M1. The U-phase conductive pattern 83 is formed in a shape along the first side h1 and the second side h2 so as not to come into contact with the first conductive pattern 81 and the second conductive pattern 82. In the U-phase conductive pattern 83, a switch element S1 which is a U-phase high-side switch element and a switch element S4 which is a U-phase low-side switch element are electrically connected. Specifically, the switch element S1 is arranged so that the arrangement direction of the drain terminal and the source terminal intersects the first side h1. In the switch element S1, the drain terminal is electrically connected to the first conductive pattern 81, and the source terminal is electrically connected to the U-phase conductive pattern 83. The gate terminal of the switch element S1 is separated from the U-phase conductive pattern 83 and is non-conductive from the U-phase conductive pattern 83. For example, the U-phase conductive pattern 83 and the gate terminal may be made non-conductive by providing a notch in the U-phase conductive pattern 83 and connecting the gate terminal to the gate conductive pattern (see, for example, FIG. 8). ), The gate terminal may be floated from the U-phase conductive pattern 83 to make it non-conductive. This is the same for the other switch elements S2 to S6. In the present embodiment, the conductive pattern is provided with a notch and the gate terminal is connected to the conductive pattern for the gate to make the conductive pattern and the gate terminal non-conductive. However, in FIG. 5, the drawing is complicated. In order to avoid this, the notch portion of the conductive pattern and the conductive pattern for the gate are omitted. In addition, in FIGS. 6, 11, and 12, which will be described below, the cutout portion of the conductive pattern is omitted as in FIG. Further, also in FIGS. 6 and 8 to 12, the conductive pattern for the gate is omitted as in FIG.

The switch element S4 is arranged so that the arrangement direction of the drain terminal and the source terminal intersects the second side h2. In the switch element S4, the drain terminal is electrically connected to the U-phase conductive pattern 83, and the source terminal is electrically connected to the second conductive pattern 82. The gate terminal of the switch element S4 is separated from the second conductive pattern 82 and is non-conductive from the second conductive pattern 82.

A V-phase conductive pattern 84 is arranged in the overhanging portion 814. The V-phase conductive pattern 84 is electrically connected to the V-phase of the motor M1. The V-phase conductive pattern 84 is formed in a shape along the third side h3 and the fourth side h4 so as not to come into contact with the first conductive pattern 81 and the second conductive pattern 82. The switch element S2, which is a V-phase high-side switch element, and the switch element S5, which is a V-phase low-side switch element, are electrically connected to the V-phase conductive pattern 84. Specifically, the switch element S2 is arranged so that the arrangement direction of the drain terminal and the source terminal intersects the third side h3. In the switch element S2, the drain terminal is electrically connected to the first conductive pattern 81, and the source terminal is electrically connected to the V-phase conductive pattern 84. The gate terminal of the switch element S2 is separated from the V-phase conductive pattern 84 and is non-conductive from the V-phase conductive pattern 84. The switch element S5 is arranged so that the arrangement direction of the drain terminal and the source terminal intersects the fourth side h4. In the switch element S5, the drain terminal is electrically connected to the V-phase conductive pattern 83, and the source terminal is electrically connected to the second conductive pattern 82. The gate terminal of the switch element S5 is separated from the second conductive pattern 82 and is non-conductive from the second conductive pattern 82.

A W-phase conductive pattern 85 is arranged in the overhanging portion 815. The W-phase conductive pattern 85 is electrically connected to the W-phase of the motor M1. The W-phase conductive pattern 85 is formed in a shape along the fifth side h5 and the sixth side h6 so as not to come into contact with the first conductive pattern 81 and the second conductive pattern 82. A switch element S3, which is a W-phase high-side switch element, and a switch element S6, which is a W-phase low-side switch element, are electrically connected to the W-phase conductive pattern 85. Specifically, the switch element S3 is arranged so that the arrangement direction of the drain terminal and the source terminal intersects the fifth side h5. In the switch element S3, the drain terminal is electrically connected to the first conductive pattern 81, and the source terminal is electrically connected to the W-phase conductive pattern 85. The gate terminal of the switch element S3 is separated from the W-phase conductive pattern 85 and is non-conductive from the W-phase conductive pattern 84. The switch element S6 is arranged so that the arrangement direction of the drain terminal and the source terminal intersects the sixth side h6. In the switch element S6, the drain terminal is electrically connected to the W-phase conductive pattern 85, and the source terminal is electrically connected to the second conductive pattern 82. The gate terminal of the switch element S6 is separated from the second conductive pattern 82 and is non-conductive from the second conductive pattern 82.

Further, the U-phase switch elements S1 and S4, the V-phase switch elements S2 and S5, and the W-phase switch elements S3 and S6 are arranged so as to be substantially uniform in the circumferential direction of the substrate 80.

Further, the substrate 80 is provided with three pairs of ceramic capacitors C1. The ceramic capacitors C1 of each pair are arranged so as to sandwich the switch elements S1, S2, and S3, which are high-side switch elements, in the circumferential direction. Each pair of ceramic capacitors C1 is electrically connected to the first conductive pattern 81 and the second conductive pattern 82.

The substrate 80 is provided with three hybrid capacitors C2. The hybrid capacitors C2 are arranged at positions facing the switch elements S1, S2, and S3, which are high-side switch elements. Each hybrid capacitor C2 is electrically connected to the first conductive pattern 81 and the second conductive pattern 82.

Here, at least one ceramic capacitor C1 of the pair of ceramic capacitors C1 is located closer to a set of switch elements (low-side switch element and high-side switch element) on the wiring path than the corresponding hybrid capacitor C2. Have been placed.

Here, the periphery of the U-phase conductive pattern 83 will be described as an example. The relationship described below is the same for the V phase and the W phase.

For example, of the pair of ceramic capacitors C1 sandwiching the switch element S4, the ceramic capacitor C1 on the switch element S1 side is closer to the set of switch elements S1 and S4 on the wiring path than the hybrid capacitor C2 facing the switch element S1. It is placed in a position. Specifically, the distance on the wiring path of the ceramic capacitor C1 on the switch element S1 side is represented by the total value of the shortest distance L1 with the switch element S1 and the shortest distance L2 with the switch element S4. On the other hand, the distance on the wiring path of the hybrid capacitor C2 is represented by the total value of the shortest distance L11 with the switch element S1 and the shortest distance L12 with the switch element S4. The smaller of these total values is arranged at a position closer to the set of switch elements S1 and S4.

On the other hand, the electrolytic capacitor C3 is electrically connected to the first conductive pattern 81 and the second conductive pattern 82 via the first bus bar 71 and the second bus bar 72. Therefore, the electrolytic capacitor C3 is arranged on the wiring path at a position farthest from the ceramic capacitor C1 and the hybrid capacitor C2 with respect to the set of switch elements. As a result, the electrolytic capacitor C3 is less susceptible to the heat from the switch elements S1 to S6.

Further, in the configuration of FIG. 5, the number of the hybrid capacitor C2 and the electrolytic capacitor C3 described above is 1: 3. As described above, the precondition is that the volume ratio of the hybrid capacitor C2 and the electrolytic capacitor C3 is 1: 5. In FIG. 5, the diameter of the electrolytic capacitor C3 is close to the diameter of the hybrid capacitor C2, but the volume ratio is 1: 5 because the height of the electrolytic capacitor C3 is larger than the height of the hybrid capacitor C2. Since it is configured in this way, the total volume of the required hybrid capacitor C2 and electrolytic capacitor C3 can be minimized, so that the power conversion device can be miniaturized.

Of the pair of ceramic capacitors C1 sandwiching the switch element S4, the ceramic capacitor C1 that is not on the switch element S1 side, that is, sandwiched between the switch element S4 and the switch element S2, has the shortest distance from the switch element S1 and the switch. The total value of the shortest distance to the element S4 is larger than the total value of the shortest distance L11 and the shortest distance L12 in the hybrid capacitor C2. Therefore, it is not necessary that all of the ceramic capacitors C1 are arranged closer to the pair of switch elements S1 and S4 than the hybrid capacitors C2, and at least one of the pair of ceramic capacitors C1 is a ceramic capacitor. It suffices that C1 is arranged at a position closer to the pair of switch elements S1 and S4 than the hybrid capacitor C2.

[4. Effect etc.]
As described above, the power conversion device (inverter 10) according to the present embodiment includes the substrate 80, the plurality of switch elements S1 to S6 provided on the substrate 80, and the DC voltage side of the switch elements S1 to S6. A first capacitor (ceramic capacitor C1), a second capacitor (hybrid capacitor C2) and a third capacitor (electrolytic capacitor C3), which are electrically connected in parallel between the positive electrode and the negative electrode, are provided. It is connected to a position closer to the switch elements S1 to S6 on the wiring path than the second capacitor and the third capacitor, and the third capacitor is located farther from the switch elements S1 to S6 on the wiring path than the second capacitor. The first capacitor has a smaller impedance in the frequency band from high frequency noise to surge, which leads to electromagnetic interference, than the second and third capacitors, and the second capacitor has a smaller impedance than the first and third capacitors. The impedance in the ripple frequency band is small, and the third capacitor has a smaller impedance in the frequency band lower than the ripple frequency band as compared with the first capacitor and the second capacitor.

According to this, the first capacitor has a smaller impedance in the frequency band from high frequency noise leading to electromagnetic interference (EMI) to surge than other capacitors, and is located closer to the switch element on the wiring path. It is arranged and the parasitic inductance caused by the wiring path is small. As a result, the first capacitor closest to the switch element can suppress high frequency noise and surge in a high frequency band ranging from high frequency noise of several hundred MHz to surge of several MHz order, for example. In addition, the third capacitor farthest from the switch element has the smallest impedance compared to other capacitors in the frequency band (for example, up to several hundred Hz) for pulsating current and current absorption at the time of abnormality, which is lower than the frequency band of ripple. Therefore, while suppressing self-heating in this frequency band, it is possible to absorb and smooth a pulsating current having a frequency significantly lower than that of a surge or ripple, or to absorb an abnormal current. The third capacitor is arranged at a position farther from the switch element on the wiring path than the other capacitors, and the parasitic inductance caused by the wiring path becomes large. As a result, the ripple current in the ripple frequency band is suppressed, so that the self-heating of the third capacitor due to the ripple current can also be suppressed. Further, since the impedance of the second capacitor arranged in the middle of the other capacitors on the wiring path is smaller than that of the other capacitors in the ripple frequency band (for example, 5 to 20 kHz), self-heating due to the ripple can be suppressed. .. The parasitic inductance of the second capacitor in the wiring path is an intermediate size between the first capacitor and the third capacitor, but since this parasitic inductance and the second capacitor act as a filter for transmitting the ripple current, the first capacitor It is possible to optimize self-heating in the second capacitor and the third capacitor.

In this way, by providing the first capacitor, the second capacitor, and the third capacitor suitable for each role, each capacitor is set to an appropriate size and number as compared with the conventional case where each role is played by two types of capacitors. can do. Therefore, since the first capacitor suppresses high-frequency noise and surge, it is not necessary to separately provide a large filter circuit for EMI countermeasures, and the size can be reduced accordingly. Further, the size of the inverter 10 itself can be reduced by determining the combination of the size and the number of each capacitor that minimizes the total volume of the first capacitor, the second capacitor, and the third capacitor.

Here, since the third capacitor has a larger impedance in each used frequency band than the other capacitors, the self-heating is also relatively large. Therefore, it is arranged at the farthest position on the wiring path. As a result, since the third capacitor is arranged away from the switch elements S1 to S6 which are heat sources, the possibility of receiving heat from the switch element in addition to self-heating is reduced. Further, the third capacitor has a large capacity as compared with other capacitors, and therefore has a large size. However, if the third capacitor is located away from the switch elements S1 to S6, the degree of freedom in space is increased, and the third capacitor is placed at an appropriate position. It becomes easy to arrange three capacitors.

Further, the wiring path between the second capacitor and the third capacitor is configured to suppress the transmission of the ripple current in the ripple frequency band.

According to this configuration, it is possible to configure a filter that suppresses the ripple current to the third capacitor by utilizing the parasitic inductance of the wiring path from the second capacitor to the third capacitor. As a result, the third capacitor suppresses self-heating due to the ripple current, so that the third capacitor, which has been enlarged for the purpose of heat resistance, can be downsized.

Further, the wiring path between the second capacitor and the third capacitor is composed of a bus bar.

According to this configuration, the parasitic inductance of the wiring path can be adjusted according to the shape and size of the bus bar, and the frequency characteristics of the filter composed of the second capacitor, the third capacitor, and the parasitic inductance of the bus bar can be adjusted in the ripple frequency band. It becomes easy to match with.

The first capacitor is a ceramic capacitor C1, the second capacitor is a hybrid capacitor C2, and the third capacitor is an electrolytic capacitor C3.

According to this, since the ceramic capacitor is the first capacitor, it is possible to effectively suppress high frequency noise and surge in the high frequency band in the above frequency band. Further, since the hybrid capacitor is the second capacitor, the ripple generated by the switching control of the motor can be effectively suppressed. Further, since the hybrid capacitor has a larger capacity per unit volume than the film capacitor, the volume for obtaining the capacity required for suppressing ripple is smaller than that of the film capacitor, and the size can be reduced. Further, even when an electrolytic capacitor having a relatively large amount of self-heating is used as the third capacitor, since it is located at the position farthest from the switch element which is a heat source on the wiring path, the switch element with respect to the electrolytic capacitor It can be less affected by the heat from. Furthermore, since the parasitic inductance in the wiring path is large, self-heating due to the ripple current is suppressed, and in the above-mentioned frequency band, suppression of low-frequency pulsating current and current absorption at the time of abnormality are effective. It can be realized.

Further, the plurality of switch elements S1 to S6 form a three-phase inverter circuit 40, and the plurality of switch elements S1 to S6 are a U-phase high-side switch element, a U-phase low-side switch element, and a V-phase high-side switch element. , V-phase low-side switch element, W-phase high-side switch element, and W-phase low-side switch element are included, and the U-phase high-side switch element (switch element S1) is a virtual regular hexagon H that fits in the substrate 80. The low-side switch element (switch element S4) of the U phase is arranged with respect to the first side h1 of the regular hexagon H1 with respect to the second side h2 adjacent to the first side h1 of the regular hexagon H, and is arranged with respect to the high side of the V phase. The switch element (switch element S2) is arranged with respect to the third side h3 adjacent to the second side h2 of the regular hexagon H, and the V-phase low side switch element (switch element S5) is the third side of the regular hexagon H. The W-phase high-side switch element (switch element S3) is arranged with respect to the fourth side h4 adjacent to h3, and is arranged with respect to the fifth side h5 adjacent to the fourth side h4 of the regular hexagon H. The phase low-side switch element (switch element S6) is arranged with respect to the sixth side h6 adjacent to the fifth side h5 of the regular hexagon H.

According to this, the high-side switch elements (switch elements S1 to S3) and the low-side switch elements (switch elements S4 to S6) of each phase are used for each side h1 to h6 of the virtual regular hexagon H that fits in the substrate. Are arranged, so that the switch elements S1 to S6 can be evenly arranged. Therefore, the inverter 10 can be made smaller.

Further, since a pair of ceramic capacitors C1 are provided in each of the U phase, the V phase, and the W phase, it is possible to further suppress the surge suppressing effect of the ceramic capacitor C1 on each phase. In this case, it is desirable that each of the pair of ceramic capacitors C1 is arranged at a position closer to the set of switch elements (low-side switch element and high-side switch element) on the wiring path than the corresponding hybrid capacitor C2. ..

[5. Modification example]
Next, a modified example of the first embodiment will be described. In the following description, the same reference numerals may be given to the parts equivalent to those in the first embodiment, and the description thereof may be omitted.

(Modification example 1)
FIG. 6 is a plan view showing the layout of each switch element and each capacitor according to the first modification.

In the first embodiment, a case where each pair of ceramic capacitors C1 are arranged so as to sandwich the high-side switch elements S1, S2, and S3 in the circumferential direction is illustrated. In this modification 1, one ceramic capacitor C1 is provided for each of the set of switch elements S1 and S4, the set of switch elements S2 and S5, and the set of switch elements S3 and S6. To do. Each ceramic capacitor C1 is arranged between each switch element S1, S2, S3 which is a high side switch element and each switch element S4, S5, S6 which is a low side switch element in each phase. Further, a hybrid capacitor C2 is newly provided at the position of the ceramic capacitor C1 excluded from the first embodiment. That is, a pair of hybrid capacitors C2 are provided in each phase. Also in this case, the ceramic capacitor C1 is arranged at a position closer to, for example, a pair of switch elements S1 and S4 on the wiring path than the pair of hybrid capacitors C2.

Further, in the first modification, the electrolytic capacitor C3 is provided in the central portion of the substrate 80. The electrolytic capacitor C3 is electrically connected to the second conductive pattern 82 and the bus bar (not shown) electrically connected to the first conductive pattern 81. Specifically, for example, in FIG. 6, the electrolytic capacitor C3 is arranged so as to stand upright with respect to the second conductive pattern 82. Then, the negative electrode of the electrolytic capacitor C3 and the second conductive pattern 82 are electrically connected. On the other hand, the positive electrode on the tip end side of the electrolytic capacitor C3 arranged upright is electrically connected to the first conductive pattern 81 by, for example, a bus bar having a crank shape. This bus bar is also configured to suppress the transmission of the ripple current in the ripple frequency band, as described in FIG. Even in this case, the electrolytic capacitor C3 is arranged at the position farthest from the ceramic capacitor C1 and the hybrid capacitor C2 on the wiring path with respect to the set of switch elements. The modified example 1 is an example of a combination in which the total volume is minimized when the number ratio of the hybrid capacitor C2 and the electrolytic capacitor C3 is 6: 1.

As described above, in the modification 1, the electrolytic capacitor C3 is arranged in the central portion of the substrate 80, and the ceramic capacitor C1 and the hybrid capacitor C2 are arranged in the outer peripheral portion of the substrate 80 rather than the electrolytic capacitor C3.

According to this, since the electrolytic capacitor C3 is arranged in the central portion of the substrate, the electrolytic capacitor C3 larger than the other capacitors can be arranged with respect to the central portion of the substrate 80 where the area can be easily secured. As a result, the area on the surface of the substrate 80 can be effectively utilized.

(Modification 2)
In the first embodiment, the case where the switch elements S1 to S6, the ceramic capacitor C1 and the hybrid capacitor C2 are directly provided on the substrate 80 has been illustrated. In this modification 2, the case where the switch elements S1 to S6, the ceramic capacitor C1 and the hybrid capacitor C2 are not directly provided on the substrate 80 will be described.

FIG. 7 is a perspective view showing a schematic configuration of the three-phase inverter circuit according to the second modification. As shown in FIG. 7, the three-phase inverter circuit 40B according to the second embodiment is provided so that U-phase, V-phase, and W-phase modules 91, 92, and 93 are erected with respect to the substrate 80b. .. The U-phase, V-phase, and W-phase modules 91, 92, and 93 are electrically connected to each phase of the motor M1 via bus bars 74, 75, and 76, respectively. Since the modules 91, 92, and 93 have basically the same configuration, the U-phase module 91 will be specifically described here by exemplifying the U-phase module 91.

FIG. 8 is a plan view showing a U-phase module according to the second modification. As shown in FIG. 8, the U-phase module 91 has a rectangular substrate 911 (first substrate) different from the substrate 80b. The substrate 921 provided in the V-phase module 92 is the second substrate, and the substrate 931 provided in the W-phase module 93 is the third substrate. The sizes of the substrates 911, 921, and 931 are substantially the same.

The substrate 911 is provided with three conductive patterns 912, 913, and 914. The conductive patterns 912 and 914 are arranged in parallel, and the conductive pattern 913 is arranged on one side of the conductive patterns 912 and 914. In the switch element S101, which is a U-phase high-side switch element, the drain terminal is electrically connected to the conductive pattern 912, and the source terminal is electrically connected to the conductive pattern 913. The conductive pattern 912 is electrically connected to the power supply line Lp via the conductive pattern on the substrate 80b. The conductive pattern 913 is formed with a notch 9131 for making the gate terminal g101 of the switch element S101 non-conductive. Since the gate terminal g101 is arranged in the notch 9131, it does not come into contact with the conductive pattern 913 and is non-conducting.

In the switch element S104, which is a U-phase low-side switch element, the drain terminal is electrically connected to the conductive pattern 913, and the source terminal is electrically connected to the conductive pattern 914. The conductive pattern 914 is electrically connected to the ground wire Lg via the conductive pattern on the substrate 80b. The conductive pattern 914 is formed with a notch 9141 for making the gate terminal g104 of the switch element S104 non-conductive. Since the gate terminal g104 is arranged in the notch 9141, it does not come into contact with the conductive pattern 914 and is non-conducting.

The ceramic capacitor C1 and the hybrid capacitor C2 are electrically connected to the conductive patterns 912 and 914. The ceramic capacitor C1 is arranged at a position closer to the conductive pattern 913 than the hybrid capacitor.

As shown in FIG. 7, the substrate 80b is a circular substrate, and the electrolytic capacitor C3 is arranged at the center thereof. The modules 91, 92, and 93 are arranged on the substrate 80b so as to surround the electrolytic capacitor C3. The electrolytic capacitor C3 is electrically connected in parallel to each of the modules 91, 92, and 93 via a conductive pattern on the substrate 80b. Therefore, the electrolytic capacitor C3 has a wiring pattern longer than that of the ceramic capacitors C1 and the hybrid capacitors C2 of each phase and the switch elements S101 and S104, and is therefore arranged at a distant position. Therefore, in FIG. 7, the parasitic inductance in the wiring path from the hybrid capacitor C2 to the electrolytic capacitor C3 is obtained without using the bus bar.

As described above, the power conversion device according to the second modification has a first substrate (board 911), a second substrate (board 921), and a third substrate (board 931) different from the substrate 80b, and has a plurality of capacitors. The switch element forms a three-phase inverter circuit, and the plurality of switch elements are a U-phase high-side switch element S101, a U-phase low-side switch element S104, a V-phase high-side switch element, a V-phase low-side switch element, and W. A phase high-side switch element and a W-phase low-side switch element are included, and the first substrate includes a U-phase high-side switch element, a U-phase low-side switch element, the U-phase high-side switch element, and the U. A first capacitor (ceramic capacitor C1) and a second capacitor (hybrid capacitor C2) that are electrically connected to the low-side switch element of the phase are provided, and a V-phase high-side switch element and a second substrate are provided. , A V-phase low-side switch element, a first capacitor and a second capacitor electrically connected to the V-phase high-side switch element and the V-phase low-side switch element are provided, and the third substrate is provided. Is a W-phase high-side switch element, a W-phase low-side switch element, and a first capacitor and a second capacitor electrically connected to the W-phase high-side switch element and the W-phase low-side switch element. The substrate 80b is provided with a third capacitor (electrolytic capacitor C3), and a first substrate, a second substrate, and a third substrate are erected so as to surround the third capacitor.

According to this, the first substrate (board 911), the U-phase high-side switch element (switch element S101), the U-phase low-side switch element (switch element S104), the first capacitor (ceramic capacitor C1), and the second capacitor. (Hybrid capacitor C2) is modularized. Similarly, the second substrate, the V-phase high-side switch element, the V-phase low-side switch element, the first capacitor, and the second capacitor are modularized. Further, the third substrate, the W-phase high-side switch element, the W-phase low-side switch element, the first capacitor and the second capacitor are modularized. Since each of these modules 91, 92, and 93 is erected with respect to the substrate 80b so as to surround the electrolytic capacitor C3, the size of the modules 91, 92, and 93 can be reduced in a plan view of the substrate 80b.

Further, the sizes of the first substrate (board 911), the second substrate (board 921), and the third substrate (board 931) are substantially the same.

According to this, since the sizes of the substrates 911, 921, and 931 of the modules 91, 92, and 93 are substantially the same, the sizes of the modules 91, 92, and 93 can be made substantially equal, and as a result. The inverter 10 can be made smaller.

(Modification 3)
In the first embodiment, the case where the switch elements S1 to S6 of each phase are arranged substantially evenly with respect to the substrate 80 is illustrated. In this modification 3, the case where the switch elements of each phase are unevenly arranged with respect to the substrate 80c will be illustrated.

FIG. 9 is a plan view showing the layout of each switch element and each capacitor according to the modified example 3.

As shown in FIG. 9, in the modified example 3, the switch elements S of each phase are non-uniformly arranged with respect to the rectangular substrate 80c. Specifically, in FIG. 9, a plurality of U-phase switch elements are arranged in the right end region of the substrate 80c, and a plurality of W-phase switch elements are arranged in the left end region. , A plurality of V-phase switch elements are arranged in the region shifted to the right from the center. In each phase, a plurality of ceramic capacitors C1 and a plurality of hybrid capacitors C2 are provided. In FIG. 9, a plurality of ceramic capacitors C1 are omitted.

FIG. 10 is a plan view showing a configuration in the vicinity of the pair of switch elements according to the third modification. FIG. 10 is an enlarged view of the alternate long and short dash line region R in FIG. As shown in FIG. 10, in the switch element S1 which is a U-phase high-side switch element, the drain terminal is electrically connected to the first conductive pattern 81b, and the source terminal is electrically connected to the U-phase conductive pattern 83b. ing. In the switch element S4, which is a U-phase low-side switch element, the drain terminal is electrically connected to the U-phase conductive pattern 83b, and the source terminal is electrically connected to the second conductive pattern 82b. The ceramic capacitor C1 and the two hybrid capacitors C2 are electrically connected in parallel to the first conductive pattern 81b and the second conductive pattern 82b. The ceramic capacitor C1 is arranged at a position closer to the switch elements S1 and S4 than the two hybrid capacitors C2.

As shown in FIG. 9, the electrolytic capacitor C3 is arranged at a position farther from the switch elements S1 and S4 than the ceramic capacitor C1 and the hybrid capacitor C2 on the wiring path. In FIG. 9, the size (diameter) of the electrolytic capacitor C3 is not the actual size but the mounting position.

(Modification example 4)
In the first embodiment, a case where a pair of switch elements is provided in each phase is illustrated. In this modification 4, a case where four pairs of switch elements are provided in each phase will be described.

FIG. 11 is a plan view showing the layout of each switch element and each capacitor according to the modified example 4. As shown in FIG. 11, in the modified example 4, four pairs of switch elements are provided for each phase. Specifically, in the U phase, four pairs of a switch element S1 which is a U-phase high-side switch element and a switch element S4 which is a U-phase low-side switch element are provided, and these are electrically connected in parallel. It is connected to the. Further, four U-phase hybrid capacitors C2 are provided, and each is arranged at a position facing each switch element S1.

In the V phase, four pairs of a switch element S2, which is a V-phase high-side switch element, and a switch element S5, which is a V-phase low-side switch element, are provided, and these are electrically connected in parallel. .. Further, four V-phase hybrid capacitors C2 are provided, and each is arranged at a position facing each switch element S2.

In the W phase, four pairs of a switch element S3 which is a W phase high side switch element and a switch element S6 which is a W phase low side switch element are provided, and these are electrically connected in parallel. .. Further, four W-phase hybrid capacitors C2 are provided, and each is arranged at a position facing each switch element S3.

Also in this case, the electrolytic capacitors (not shown) are the first bus bar (not shown) electrically connected to the first conductive pattern 81 and the second bus bar 72 electrically connected to the second conductive pattern 82. It is electrically connected to. Therefore, the electrolytic capacitor is arranged at the position farthest from each switch element on the wiring path than the ceramic capacitor C1 and the hybrid capacitor C2.

(Modification 5)
In the fourth modification, the case where the first conductive pattern 81 is provided along the entire circumference of the outer periphery of the substrate 80 is illustrated. In this modification 5, the case where the first conductive pattern is provided only in the vicinity of the high side switch element of each phase will be described.

FIG. 12 is a plan view showing the layout of each switch element and each capacitor according to the modified example 5. As shown in FIG. 12, in the modified example 5, the first conductive pattern 81d is divided into three, and each first conductive pattern 81d is in the vicinity of the switch elements S1, S2, and S3, which are high-side switch elements of each phase. Is located in. Each first conductive pattern 81d is electrically connected from the back surface side of the substrate 80 by a bus bar 75. An electrolytic capacitor is electrically connected to the bus bar 75 and a bus bar (not shown) electrically connected to the second conductive pattern 82. Therefore, the electrolytic capacitor is arranged at the position farthest from each switch element on the wiring path than the ceramic capacitor C1 and the hybrid capacitor C2.

(Modification 6)
In the first embodiment, the case where the switch elements S1 to S6, the ceramic capacitor C1 and the hybrid capacitor C2 are directly provided on the substrate 80 has been illustrated. In this modification 6, a case where each circuit component is mounted on the first substrate and the second substrate arranged so as to face each other will be described.

FIG. 13 is a side view showing the layout of each switch element and each capacitor according to the modified example 6. As shown in FIG. 13, the first substrate 81e is provided with at least one switch element S and at least one ceramic capacitor C1. On the other hand, the second substrate 82e is provided with at least one hybrid capacitor C2, at least one electrolytic capacitor C3, and a control IC 99. The first substrate 81e and the second substrate 82e are electrically connected to each other. With reference to each switch element S, the ceramic capacitor C1 is arranged at the closest position on the wiring path, the hybrid capacitor C2 is arranged at the next closest position, and the electrolytic capacitor C3 is arranged at the farthest position.

As described above, in the modification 6, the switch element S and the ceramic capacitor C1 (first capacitor) are provided on the first substrate 81e, and the hybrid capacitor C2 (second capacitor) and the electrolytic capacitor C3 (third capacitor) are provided. Is provided on the second substrate 82e facing the first substrate 81e.

According to this, the first substrate 81e provided with the switch element S and the ceramic capacitor C1 and the second substrate 82e provided with the hybrid capacitor C2 and the electrolytic capacitor C3 are arranged so as to face each other. The first substrate 81e and the second substrate 82e overlap in a plan view. Therefore, the converter can be made smaller.

(Modification 7)
In the first embodiment, the regular hexagonal substrate 80 has been illustrated and described. In this modification 7, the circular substrate 80f will be illustrated and described.

FIG. 14 is a plan view showing the substrate 80f according to the modified example 7. As shown in FIG. 14, the substrate 80f has a circular shape in a plan view, and the first conductive pattern 81f, the second conductive pattern 82, the U-phase conductive pattern 83, the V-phase conductive pattern 84, and W on one main surface. A phase conductive pattern 85 is provided. The first conductive pattern 81f is a conductive pattern on the positive electrode side and has a circular outer shape. In FIG. 14, the alternate long and short dash line is a virtual circle Cf that fits within the substrate 80. The virtual circle Cf, the outer shape of the substrate 80, and the outer shape of the first conductive pattern 81f are concentric circles. A plurality of switch elements S1 to S6 are arranged along the virtual circle Cf. Specifically, the plurality of switch elements S1 to S6 are positioned so as to overlap the virtual circle Cf, and are arranged at equal intervals in the circumferential direction.

Since the plurality of switch elements S1 to S6 are arranged along the virtual circle Cf that fits in the substrate 80 in this way, the switch elements S1 to S6 can be evenly arranged from the center of the substrate 80. Therefore, the power conversion device can be made smaller.

Although the case where the virtual circle Cf and the outer shape of the substrate 80 are concentric circles is illustrated here, the virtual circle Cf may be any virtual circle that fits in the substrate 80. Therefore, the outer shape of the substrate 80 may be a shape other than the circular shape.

(Embodiment 2)
In the second embodiment, a three-phase inverter circuit to which a bus bar capable of three-dimensional wiring is applied will be described. FIG. 15 is a plan view showing a schematic configuration of the three-phase inverter circuit 40G according to the second embodiment. Specifically, FIG. 15 is a diagram corresponding to FIG.

As shown in FIG. 15, the three-phase inverter circuit 40G according to the second embodiment includes a bus bar 130 as an electrical connection member. The bus bar 130 electrically connects the first conductive pattern 81 and the second conductive pattern 82.

The bus bar 130 according to the second embodiment will be described below with reference to FIGS. 16 to 18. The arrangement direction of the mounting board 110, the bus bar 130, and the board 80 is defined as the Z-axis direction. The Z-axis direction may be referred to as a vertical direction. The X-axis direction and the Y-axis direction are orthogonal to each other and are also orthogonal to the Z-axis direction.

[Constitution]
FIG. 16 is a perspective view showing 100 g of the electrical connection structure according to the second embodiment. In FIG. 16, the substrate 80 is cut along the XVI-XVI cutting line shown in FIG. 15, and the portion is enlarged and shown in a perspective view. As shown in FIG. 16, the electrical connection structure 100 g includes a mounting board 110, a board 80, and a bus bar 130 mounted on the board 80. Note that FIG. 16 shows a state before the mounting board 110 and the board 80 are assembled.

The mounting board 110 is, for example, a printed circuit board or a metal board, and is a plate-shaped member parallel to the XY plane. The mounting board 110 is electrically connected to the bus bar 130 in a state of facing the board 80. Specifically, the connector 11 connected to the bus bar 130 is mounted on the main surface of the mounting board 110 on the board 80 side (plus side in the Z-axis direction). Although not shown, the electrolytic capacitor C3 is electrically arranged on the mounting board 110 so as to be conductive on the connector 11. As a result, the electrolytic capacitor C3 is connected to a position farther from the switch elements S1 to S6 on the wiring path than the hybrid capacitor C2.

The substrate 80 is a printed circuit board or a metal substrate, but in the present embodiment, a case where the substrate 80 is a metal substrate is illustrated. The substrate 80 is a plate-shaped member parallel to the XY plane. The substrate 80 is formed on a flat metal layer 21, an insulating layer 22 laminated on the entire surface of the main surface of the metal layer 21 on the mounting substrate 110 side, and a first surface of the insulating layer 22 on the mounting substrate 110 side. It includes a conductive pattern 81 and a second conductive pattern 82. As a result, the mounting board 110 and the board 80 are three-dimensionally arranged via the bus bar 130 and the connector 11 connected to the bus bar 130. As a result, the mounting board 110 and the board 80 can be mounted at high density.

A heat radiating portion (not shown) is attached to the main surface of the metal layer 21 on the side opposite to the second substrate 120 side (minus side in the Z-axis direction) in a heat conductive state. Examples of the heat radiating unit include heat radiating fins, a water cooler, an air cooler, an oil cooler, and the like.

The first conductive pattern 81 and the second conductive pattern 82 are arranged at predetermined intervals in the X-axis direction. Each of the first conductive pattern 81 and the second conductive pattern 82 is electrically connected to a DC power supply. Of the first conductive pattern 81 and the second conductive pattern 82, the first conductive pattern 81 arranged on the negative side in the X-axis direction is the conductive pattern on the negative electrode side, and the second conductive pattern arranged on the positive side in the X-axis direction. The pattern 82 is a conductive pattern on the positive electrode side. A bus bar 130 is electrically connected to the first conductive pattern 81 and the second conductive pattern 82 via solder portions 25 and 26.

Further, a pair of recesses 27 and 28 are formed on the main surface of the substrate 80 on the mounting substrate 110 side with respect to the region between the first conductive pattern 81 and the second conductive pattern 82. The pair of recesses 27, 28 are arranged along the Y-axis direction. The pair of recesses 27, 28 may be through holes or holes having a bottom.

Next, the details of the bus bar 130 will be described. FIG. 17 is a cross-sectional view of the bus bar 130 according to the second embodiment. FIG. 18 is a side view of the bus bar 130 according to the second embodiment. In FIG. 18, only the substrate 80 is shown in cross-sectional view.

As shown in FIGS. 16 to 18, the bus bar 130 includes a first bus bar 31, a second bus bar 32, and an insulating portion 33. In this embodiment, the case where the first bus bar 31 and the second bus bar 32 are common parts will be illustrated. Therefore, in the following description, the first bus bar 31 will be described in detail.

As shown in FIG. 17, the first bus bar 31 is a metal sheet metal formed in an L-shape in cross section. Specifically, the first bus bar 31 integrally includes a first connecting portion 311 which is an L-shaped short side portion and a first standing portion 312 which is an L-shaped long side portion. ..

The first connecting portion 311 is a flat plate-shaped portion parallel to the XY plane, and is electrically connected to the first conductive pattern 81 of the second substrate 120 via the solder portion 25. The first erecting portion 312 is a flat plate-shaped portion parallel to the YZ plane, and is erected from one end (the end on the positive side in the X-axis direction) of the first connecting portion 311 toward the positive side in the Z-axis direction. ing. As shown in FIG. 18, the upper end portion of the first standing portion 312 has a shape that tapers toward the upper side. Specifically, the upper end surface 313 of the first standing portion 312 is flat, and each pair of portions sandwiching the upper end surface 313 is an inclined portion 314. Although the inclined portion 314 exemplifies the case where it is curved in a concave shape in FIG. 18, it may be curved in a convex shape or inclined in a straight line.

The second bus bar 32 is a part common to the first bus bar 31, that is, a part having the same shape as the first bus bar 31. The posture (orientation) of the second bus bar 32 at the time of installation is different from that of the first bus bar 31. The correspondence between each part of the second bus bar 32 and each part of the first bus bar 31 is such that the first connection part 311 and the second connection part 321 correspond to each other, and the first standing part 312 and the second standing part 322. Corresponds, the upper end surface 313 corresponds to the upper end surface 323, and the inclined portion 314 corresponds to the inclined portion 324.

The insulating portion 33 is a member that insulates the first bus bar 31 and the second bus bar 32 and holds the first bus bar 31 and the second bus bar 32. Specifically, the insulating portion 33 is, for example, a substantially rectangular parallelepiped insulating resin, and covers a part of the first bus bar 31 and the second bus bar 32. For example, the insulating portion 33 is formed by insert molding together with the first bus bar 31 and the second bus bar 32.

In the state of being held by the insulating portion 33, the first bus bar 31 and the second bus bar 32 are arranged at predetermined intervals in the X-axis direction in a posture of facing backward with respect to a plane parallel to the XZ plane. There is. Specifically, in the first bus bar 31, the first connecting portion 311 faces the minus side in the X-axis direction, and the first standing portion 312 faces the plus side in the X-axis direction. On the contrary, in the second bus bar 32, the second connecting portion 321 faces the plus side in the X-axis direction, and the second standing portion 322 faces the minus side in the X-axis direction. As a result, the first erection portion 312 and the second erection portion 322 face each other with a predetermined interval. An insulating portion 33 is filled between the first erection portion 312 and the second erection portion 322 to insulate the portion. The portion of the insulating portion 33 filled between the first standing portion 312 and the second standing portion 322 is referred to as an intermediate portion 331.

The upper portion of the first standing portion 312 and the upper portion of the second standing portion 322 project from the upper surface of the insulating portion 33. The connector 11 is fitted into the upper part of the first upright portion 312 and the upper part of the second upright portion 322 to be electrically connected.

The tip of the first connecting portion 311 projects from the side surface of the insulating portion 33 on the minus side in the X-axis direction. The peripheral portion of the first connecting portion 311 protruding from the insulating portion 33 is soldered to the first conductive pattern 81 by the solder portion 25 over the entire circumference. The lower surface of the first connecting portion 311 is flush with the lower surface of the insulating portion 33 and is exposed from the insulating portion 33. The lower surface of the first connecting portion 311 is electrically connected to the first conductive pattern 81 by soldering with the solder portion 25.

The tip of the second connecting portion 321 protrudes from the side surface of the insulating portion 33 on the positive side in the X-axis direction. The peripheral portion of the second connecting portion 321 protruding from the insulating portion 33 is soldered to the second conductive pattern 82 by the solder portion 26 over the entire circumference. The lower surface of the second connecting portion 321 is flush with the lower surface of the insulating portion 33 and is exposed from the insulating portion 33. The lower surface of the second connecting portion 321 is electrically connected to the second conductive pattern 82 by soldering with the solder portion 26.

As shown in FIGS. 17 and 18, a pair of downwardly projecting convex portions 332 and 333 are formed on the lower surface of the intermediate portion 331 of the insulating portion 33. The pair of convex portions 332 and 333 may have any shape as long as they have a shape that fits the pair of concave portions 27 and 28. For example, when the pair of recesses 27 and 28 are columnar recesses, the pair of convex portions 332 and 333 are also columnar convex portions. Since the pair of convex portions 332 and 333 fit into the pair of concave portions 27 and 28, the bus bar 130 can be stabilized on the substrate 80 even before soldering. In particular, in the present embodiment, since the plurality of convex portions (convex portions 332 and 333) are fitted into the plurality of concave portions (concave portions 27 and 28), the rotation of the bus bar 130 on the substrate 80 is restricted. The bus bar 130 can be made more stable. The number of recesses and protrusions to be installed may be one or more.

Next, the electrical action on the first bus bar 31 and the second bus bar 32 will be described. When each of the first bus bar 31 and the second bus bar 32 is held by the insulating portion 33, the first standing portion 312 and the second standing portion 322 are insulated by the intermediate portion 331. They face each other at a predetermined interval. In the first bus bar 31, the first connecting portion 311 is electrically connected to the first conductive pattern 81 on the negative electrode side, and in the second bus bar 32, the second connecting portion 321 is connected to the second conductive pattern 82 on the positive electrode side. Since they are electrically connected, the directions of the currents flowing through the first bus bar 31 and the second bus bar 32 are opposite to each other. Therefore, the magnetic field caused by the current flowing through the first standing portion 312 of the first bus bar 31 and the magnetic field caused by the current flowing through the second standing portion 322 of the second bus bar 32 cancel each other out. As a result, the inductance of the bus bar 130 as a whole is reduced.

The distance H between the first standing portion 312 of the first bus bar 31 and the second standing portion 322 of the second bus bar 32 may be any distance as long as the magnetic fields can cancel each other out. Specifically, the length L of the first connection portion 311 or the second connection portion 321 may be smaller than the length L, and more specifically, the length may be 1 mm or less.

[Effects, etc.]
As described above, the bus bar 130 according to the present embodiment has a first connecting portion 311 electrically connected to the substrate 80 and a first standing portion erected from one end of the first connecting portion 311. A first bus bar 31 having a 312, a second connecting portion 321 electrically connected to the substrate 80, and a second standing portion 322 erected from one end of the second connecting portion 321. An insulating portion that holds the first bus bar 31 and the second bus bar 32 so that the second bus bar 32, the first standing portion 312, and the second standing portion 322 face each other with a predetermined interval in an insulated state. 33, one of the first bus bar 31 and the second bus bar 32 is electrically connected to the positive electrode of the DC power supply, and the other of the first bus bar 31 and the second bus bar 32 is electrically connected to the negative electrode of the DC power supply. ing.

According to this, one of the first bus bar 31 and the second bus bar 32 is electrically connected to the positive electrode of the DC power supply, and the other of the first bus bar 31 and the second bus bar 32 is electrically connected to the negative electrode of the DC power supply. ing. Therefore, the magnetic field caused by the current flowing through the first standing portion 312 of the first bus bar 31 and the magnetic field caused by the current flowing through the second standing portion 322 of the second bus bar 32 are in opposite directions. .. Since the first erection part 312 and the second erection part 322 face each other with a predetermined interval via the insulating part 33, the magnetic field generated in the first erection part 312 and the second The magnetic fields generated in the upright portion 322 cancel each other out, and as a result, the inductance can be reduced. Therefore, in addition to high-density mounting due to the three-dimensional arrangement of the mounting board 110 and the board 80, indentance can be reduced.

Further, one of the first connection portion 311 and the second connection portion 321 is connected to the first conductive pattern 81 on the negative electrode side provided on the substrate 80 by soldering, and the first connection portion 311 and the second connection portion are connected. The other side of the 321 is connected to the second conductive pattern 82 on the positive electrode side provided on the substrate 80 by soldering.

According to this, both the first connecting portion 311 and the second connecting portion 321 are connected to the first conductive pattern 81 and the second conductive pattern 82 on the substrate 80 by soldering. The one connection portion 311 and the second connection portion 321 can be easily connected to the first conductive pattern 81 and the second conductive pattern 82 on the substrate 80. Since both the first connection portion 311 and the second connection portion 321 are soldered to the first conductive pattern 81 and the second conductive pattern 82 without passing through the through holes, the connection area can be increased and the connection strength can be increased. Is possible.

The substrate 80 is a metal substrate.

According to this, since the substrate 80 is a metal substrate, the heat generated by the bus bar 130 can be efficiently dissipated through the metal substrate. As a result, it is possible to prevent the switching elements S1 to S6 from running out of control due to the heat from the bus bar 130, and it is possible to more reliably suppress the increase in voltage of the switching elements S1 to S6.

Further, at least one convex portions 332 and 333 are formed on one of the intermediate portion 331 between the first connection portion 311 and the second connection portion 321 of the insulating portion 33 and the substrate 80, and the intermediate portion is intermediate. At least one recesses 27 and 28 into which at least one convex portions 332 and 333 are individually fitted are formed on the other side of the portion 331 and the substrate 80.

According to this, the convex portions 332 and 333 provided on one of the intermediate portion 331 and the substrate 80 are fitted to the recesses 27 and 28 provided on the other side of the intermediate portion 331 and the substrate 80. Therefore, the bus bar 130 and the substrate 80 can be stably held even before the work of connecting to the first conductive pattern 81 and the second conductive pattern 82. Therefore, during the connection work, the bus bar 130 is less likely to be displaced with respect to the substrate 80, and the connection work can be easily performed.

(Embodiment 3)
Next, the bus bar 130h according to the third embodiment will be described. The bus bar 130h according to the third embodiment is different from the bus bar 130 according to the above embodiment in that an electrolytic capacitor C3 is installed between the first bus bar 31 and the second bus bar 32. That is, in the third embodiment, the electrolytic capacitor C3 is removed from the mounting board 110. In the following description, the same parts as those in the above embodiment may be designated by the same reference numerals and the description thereof may be omitted.

FIG. 19 is a perspective view showing the electrical connection structure 100h according to the third embodiment. FIG. 20 is a cross-sectional view of the bus bar 130h according to the third embodiment. FIG. 21 is a side view of the bus bar 130h according to the third embodiment. In FIG. 21, only the substrate 80 is shown in cross-sectional view.

As shown in FIGS. 19 to 21, an electrolytic capacitor C3 is arranged between the first standing portion 312 of the first bus bar 31 and the second standing portion 322 of the second bus bar 32.

In the present embodiment, a plurality of electrolytic capacitors C3 are provided, but one may be provided. Specifically, six electrolytic capacitors C3 are provided, and are held between the first standing portion 312 and the second standing portion 322 by the intermediate portion 331 of the insulating portion 33. The plurality of electrolytic capacitors C3 are electrically connected to the first erection portion 312 and the second erection portion 322 in parallel. As a result, the ripple noise can be reduced because the plurality of electrolytic capacitors C3 smooth the current.

As described above, the bus bar 130h according to the present embodiment is first erected in a state of being held by the insulating portion 33 and arranged between the first erection portion 312 and the second erection portion 322. It has an electrolytic capacitor C3 that is electrically connected to the portion 312 and the second upright portion 322.

According to this, the electrolytic capacitor C3 arranged between the first standing portion 312 and the second standing portion 322 is electrically connected to the first standing portion 312 and the second standing portion 322. Therefore, the ripple noise of the current flowing through the first bus bar 31 and the second bus bar 32 can be reduced.

Further, since the electrolytic capacitor C3 is arranged between the first bus bar 31 and the second bus bar 32, the wiring path to the electrolytic capacitor C3 can be shortened. Therefore, it is possible to further reduce the inductance.

Further, a plurality of electrolytic capacitors C3 are provided, and the plurality of electrolytic capacitors C3 are electrically connected in at least one form of series, parallel and series-parallel.

According to this, since the plurality of electrolytic capacitors C3 are electrically connected in at least one form of series, parallel and series-parallel, it is possible to adjust the number, combination and connection form of the plurality of electrolytic capacitors C3. It can be adjusted to a desired capacitance value and withstand voltage value.

A hybrid capacitor C2 is arranged between the first standing section 312 and the second standing section 322 instead of the electrolytic capacitor C3, and the hybrid capacitor C2 is placed between the first standing section 312 and the second standing section 312. It may be electrically connected to the installation unit 322. In this case, the wiring path for the hybrid capacitor C2 can be shortened. Further, also in the hybrid capacitor C2, a plurality of hybrid capacitors C2 can be arranged between the first standing portion 312 and the second standing portion 322. In this case, the plurality of hybrid capacitors C2 are electrically connected in at least one form of series, parallel and series-parallel. Thereby, the number, combination, and connection form of the plurality of hybrid capacitors C2 can be adjusted, and the desired capacitance value and withstand voltage value can be adjusted.

Here, when only the hybrid capacitor C2 is arranged between the first upright portion 312 and the second upright portion 322, the electrolytic capacitor C3 may be electrically arranged on the mounting board 110 and on the connector 11. .. As a result, the electrolytic capacitor C3 is connected to a position farther from the switch elements S1 to S6 on the wiring path than the hybrid capacitor C2.

Further, when both the hybrid capacitor C2 and the electrolytic capacitor C3 are arranged between the first standing portion 312 and the second standing portion 322, the electrolytic capacitor C3 is arranged at a position far from the substrate 80, and the hybrid capacitor is arranged. C2 may be arranged at a position close to the substrate 80. As a result, the electrolytic capacitor C3 is connected to a position farther from the switch elements S1 to S6 on the wiring path than the hybrid capacitor C2.

(Other)
The power conversion device according to the present disclosure has been described above based on each of the above-described embodiments and modifications, but the present disclosure is not limited to the above-described embodiments and modifications.

For example, in the first embodiment, the inverter 10 is exemplified as the power conversion device, but the power conversion device may be any device as long as it has a function of converting power. Examples of the power conversion device other than the inverter 10 include a converter.

Further, in the above embodiment, the case where the substrate 80 has a regular hexagonal shape or a circular shape in a plan view is illustrated, but the plan view shape of the substrate may be arbitrary. Examples of the plan view shape of the substrate include polygonal shapes other than regular hexagons and elliptical shapes other than circular shapes. Regardless of the shape of the board, if a virtual regular hexagon or circle can be created in the board, each switch element can be arranged on each side of the regular hexagon or along the circle. Is.

Further, in the above embodiment, the ceramic capacitor C1 is exemplified as the first capacitor, the hybrid capacitor C2 is exemplified as the second capacitor, and the electrolytic capacitor C3 is exemplified as the third capacitor. However, as long as the condition that the first capacitor has a higher impedance than the second capacitor and the third capacitor and the third capacitor has a lower impedance than the second capacitor is satisfied, any type of each capacitor can be used. Good. For example, a film capacitor may be added to a ceramic capacitor, a hybrid capacitor, and an electrolytic capacitor to form a combination of these four types of capacitors that satisfies the above-mentioned conditions.

Further, the inductor may be electrically connected to the wiring path between the hybrid capacitor C2 and the electrolytic capacitor C3. Specifically, the inductor may be connected in series at the position P shown in FIG. If the inductor is electrically connected in series with the wiring path, the inductance value of the combined inductor of the inductance value of the wiring path and the inductance value of the inductor can be adjusted by adjusting the inductance value of the inductor. .. By adjusting the inductance value of the composite inductor, it is possible to further suppress the transmission of ripple current. The inductor may be connected in parallel with the wiring path.

Further, in the first embodiment, for example, as shown in FIG. 5, the directions of the terminals of the switch elements S1 to S6 are in the direction toward the center of the substrate 80 or in the direction away from the center of the switch elements S1 to S1. Although S6 is arranged, it is not limited to such an arrangement configuration. For example, FIG. 22 is a plan view showing another layout of each switch element and each capacitor according to the first embodiment. As shown in FIG. 22, the switch elements S1 to S6 are arranged so that the directions of the terminals of the switch elements S1 to S6 are the same as (parallel) to each side of the plan view regular hexagonal shape of the substrate 80. ing. With such a configuration, for example, the distance between the switch element S1, the switch element S4, and the ceramic capacitor C1 and the distance between the switch element S1, the switch element S4, and the hybrid capacitor C2 can all be set. Since it can be made shorter than in the case of FIG. 5, it is possible to further suppress surges and ripples. In addition, since the distance is shortened, the substrate 80 can be miniaturized. By adopting the same configuration as described above, the circular substrate 80f of FIG. 14 can also suppress surges and ripples and can be miniaturized.

Further, in the second embodiment, the case where the first bus bar 31 is L-shaped in cross section, that is, the angle formed by the first connecting portion 311 and the first standing portion 312 is approximately 90 degrees. However, if the first erection part 312 is erected with respect to the first connection part 311, the angle between the first connection part and the first erection part is other than 90 degrees. May be good. Further, the first erection portion may be erected in a curved shape even if it is not erected in a straight line in cross section. This also applies to the second bus bar.

Further, in the second embodiment, the case where the first bus bar 31 and the second bus bar 32 have the same shape is illustrated, but the first bus bar and the second bus bar may have different shapes.

Further, in the second embodiment, the case where the first connecting portion 311 and the second connecting portion 321 are soldered to the first conductive pattern 81 and the second conductive pattern 82 is illustrated. However, the connection form between the first connection portion and the second connection portion and the conductive pattern may be arbitrary. Other connection forms include, for example, a connection form by mechanical fastening such as caulking and screwing, and a connection form by welding such as resistance welding or laser welding.

Further, in the second embodiment, the case where the substrate 80 is a metal substrate has been illustrated, but the substrate may be a substrate formed of a material other than metal.

Further, in the second embodiment, the case where the convex portions 332 and 333 are formed on the insulating portion 33 and the concave portions 27 and 28 are formed on the substrate 80 is illustrated, but the concave portion is formed on the insulating portion and the second A convex portion that fits into the concave portion may be formed on the substrate.

Further, in the second embodiment, the case where the insulating portion 33 is formed by insert molding together with the first bus bar 31 and the second bus bar 32 is illustrated, but the insulating portion 33 is the first bus bar 31. Any manufacturing method may be used as long as it is filled between the one standing portion 312 and the second standing portion 322 of the second bus bar 32 to insulate them. For example, the insulating portion may be a sheet-shaped insulating body interposed between the first standing portion and the second standing portion.

Further, in the above embodiment, the case where the connector 11 mounted on the mounting board 110 is connected to the bus bar 130 is illustrated, but the connector connected to the cable may be connected to the bus bar. Connection terminals (screws, etc.) other than connectors may be connected to the bus bar.

Further, in the second embodiment, for example, as shown in FIG. 15, the directions of the terminals of the switch elements S1 to S6 are in the direction toward the center of the substrate 80 or in the direction away from the center. Although S6 is arranged, it is not limited to such an arrangement configuration. For example, FIG. 23 is a plan view showing another schematic configuration of the three-phase inverter circuit according to the second embodiment. As shown in FIG. 23, the switch elements S1 to S6 are arranged so that the directions of the terminals of the switch elements S1 to S6 are the same as (parallel) to each side of the plan view regular hexagonal shape of the substrate 80. ing. Then, the bus bar 130 is electrically connected to the first conductive pattern 81 and the second conductive pattern 82. With such a configuration, for example, the distance between the switch element S1, the switch element S4, and the ceramic capacitor C1 and the distance between the switch element S1, the switch element S4, and the hybrid capacitor C2 can all be set. Since it can be made shorter than in the case of FIG. 15, it is possible to further suppress surges and ripples. In addition, since the distance is shortened, the substrate 80 can be miniaturized.

Further, the substrate 80 may be arranged parallel to the surface orthogonal to the rotation axis of the motor M1 and on the end surface side of the motor M1. Specifically, the substrate 80 may be arranged on the end surface side of the motor M1 opposite to the rotation axis and parallel to the surface orthogonal to the rotation axis. Further, the substrate 80 may be arranged on the end surface side of the motor M1 where the rotation axis is located, in parallel with the surface orthogonal to the rotation axis. In this case, it is desirable that the substrate 80 is provided with a through hole through which the rotating shaft penetrates.

In either case, the substrate 80 and the motor M1 overlap each other in the axial direction. Therefore, the substrate 80 and the motor M1 can be arranged compactly, and the power conversion device can be made smaller.

In addition, it is realized by arbitrarily combining the embodiments obtained by applying various modifications to the embodiments that can be conceived by those skilled in the art, and the embodiments and the components and functions in each modification without departing from the spirit of the present disclosure. The form to be used is also included in the present disclosure.

As described above, this disclosure is useful as a power conversion device provided in a vehicle drive device.

1 Electric vehicle 2 Drive wheels 3 Power transmission mechanism 5 Vehicle drive device 10 Inverter (electric power converter)
11 Conductor 20 Control circuit 21 Metal layer 22 Insulation layer 25, 26 Solder part 27, 28 Recessed part 30 Drive circuit 31, 71 First bus bar 32, 72 Second bus bar 33 Insulation part 40, 40B Three-phase inverter circuit 74, 75, 76 , 130, 130h Bus bar 80, 80b, 80c Substrate 81, 81b, 81d First conductive pattern 81e First substrate 82, 82b Second conductive pattern 82e Second substrate 83, 83b U-phase conductive pattern 84 V-phase conductive pattern 85 W-phase Conductive pattern 91, 92, 93 Module 99 Control IC
100g, 100h Electrical connection structure 110 Mounting board 311 First connection part 312 First standing part 313, 323 Upper end surface 314, 324 Inclined part 321 Second connection part 322 Second standing part 331 Intermediate part 332, 333 Convex part 811 Opening 812 Central opening 813, 814, 815 Overhang 911 Substrate (first substrate)
912, 913, 914 Conductive pattern 921 substrate (second substrate)
931 board (third board)
9131 Notch 9141 Notch C1 Ceramic Capacitor (First Capacitor)
C2 hybrid capacitor (second capacitor)
C3 electrolytic capacitor (third capacitor)
Cf virtual circle CSu, CSv, CSw Current sensor g101 Gate terminal g104 Gate terminal H Interval h1 First side h2 Second side h3 Third side h4 Fourth side h5 Fifth side h6 Sixth side L Length Lg Ground wire Lp Power supply Wire M1 Permanent magnet motor (motor)
P1 Battery RS Rotation Position Sensor S, S1, S2, S3, S4, S5, S6, S101, S104 Switch Element

Claims (19)

With the board
A plurality of switch elements provided on the substrate and
A first capacitor, a second capacitor, and a third capacitor, which are electrically connected in parallel between the positive electrode and the negative electrode on the DC voltage side of the switch element, are provided.
The first capacitor is connected to a position closer to the switch element on the wiring path than the second capacitor and the third capacitor.
The third capacitor is connected to a position farther from the switch element on the wiring path as compared with the second capacitor.
The first capacitor has a smaller impedance in the frequency band from high frequency noise to surge, which leads to electromagnetic interference, than the second capacitor and the third capacitor.
The second capacitor has a smaller impedance in the ripple frequency band than the first capacitor and the third capacitor.
The third capacitor is a power conversion device having a smaller impedance in a frequency band lower than the frequency band of the ripple as compared with the first capacitor and the second capacitor. The power conversion device according to claim 1, wherein the wiring path between the second capacitor and the third capacitor is configured to suppress the transmission of the ripple current in the frequency band of the ripple. The power conversion device according to claim 2, wherein the wiring path between the second capacitor and the third capacitor is composed of a bus bar. The power conversion device according to claim 3, wherein the bus bar is configured to suppress transmission of the ripple current by adjusting at least one of a shape, a size, and a material. The power conversion device according to claim 2, wherein an inductor is electrically connected to the wiring path. The first capacitor is a ceramic capacitor
The second capacitor is a hybrid capacitor and
The power conversion device according to claim 1, wherein the third capacitor is an electrolytic capacitor. The plurality of switch elements form a three-phase inverter circuit.
The plurality of switch elements include a U-phase high-side switch element, a U-phase low-side switch element, a V-phase high-side switch element, a V-phase low-side switch element, a W-phase high-side switch element, and a W-phase low-side switch. Including the element
The U-phase low-side switch element is arranged with respect to the first side of a virtual regular hexagon that fits within the substrate.
The U-phase high-side switch element is arranged with respect to a second side adjacent to the first side of the regular hexagon.
The V-phase low-side switch element is arranged with respect to a third side adjacent to the second side of the regular hexagon.
The V-phase high-side switch element is arranged with respect to the fourth side adjacent to the third side of the regular hexagon.
The W-phase low-side switch element is arranged with respect to the fifth side adjacent to the fourth side of the regular hexagon.
The power conversion device according to any one of claims 1 to 6, wherein the W-phase high-side switch element is arranged with respect to a sixth side adjacent to the fifth side of the regular hexagon. The third capacitor is arranged in the center of the substrate.
The power conversion device according to claim 7, wherein the first capacitor and the second capacitor are arranged on the outer peripheral portion of the substrate more than the third capacitor. It has a first substrate, a second substrate, and a third substrate that are different from the substrate.
The plurality of switch elements form a three-phase inverter circuit.
The plurality of switch elements include a U-phase high-side switch element, a U-phase low-side switch element, a V-phase high-side switch element, a V-phase low-side switch element, a W-phase high-side switch element, and a W-phase low-side switch. Including the element
The U-phase high-side switch element, the U-phase low-side switch element, the U-phase high-side switch element, and the U-phase low-side switch element are electrically connected to the first substrate. A first capacitor and the second capacitor are provided, and
The second substrate is electrically connected to the V-phase high-side switch element, the V-phase low-side switch element, the V-phase high-side switch element, and the V-phase low-side switch element. A first capacitor and the second capacitor are provided, and
The third substrate is electrically connected to the W-phase high-side switch element, the W-phase low-side switch element, the W-phase high-side switch element, and the W-phase low-side switch element. A first capacitor and the second capacitor are provided, and
Any of claims 1 to 6, wherein the third substrate is provided on the substrate, and the first substrate, the second substrate, and the third substrate are erected so as to surround the third capacitor. The power conversion device according to item 1. The power conversion device according to claim 9, wherein the sizes of the first substrate, the second substrate, and the third substrate are substantially the same. The switch element and the first capacitor are provided on the first substrate.
The power conversion device according to any one of claims 1 to 6, wherein the second capacitor and the third capacitor are provided on a second substrate facing the first substrate. The power conversion device according to any one of claims 1 to 6, wherein the plurality of switch elements are arranged along a virtual circle that fits in the substrate. The plurality of switch elements form a three-phase inverter circuit for driving a motor.
The power conversion device according to any one of claims 1 to 12, wherein the substrate is arranged parallel to a surface orthogonal to the rotation axis of the motor and on the end surface side of the motor. The bus bar
A first bus bar having a first connecting portion electrically connected to the substrate and a first standing portion erected from one end of the first connecting portion.
A second bus bar having a second connecting portion electrically connected to the substrate and a second standing portion erected from one end of the second connecting portion.
The first bus bar and the insulating portion holding the second bus bar are provided so that the first standing portion and the second standing portion face each other at a predetermined interval in an insulated state.
3. One of the first bus bar and the second bus bar is electrically connected to the positive electrode of the DC power supply, and the other of the first bus bar and the second bus bar is electrically connected to the negative electrode of the DC power supply. Or the power conversion device according to 4. One of the first connection portion and the second connection portion is connected to a conductive pattern on the positive electrode side provided on the substrate by soldering.
The power conversion device according to claim 14, wherein the other of the first connection portion and the second connection portion is connected to a conductive pattern on the negative electrode side provided on the substrate by soldering. The power conversion device according to claim 14 or 15, wherein the substrate is a metal substrate. At least one convex portion is formed on one of the intermediate portion between the first connecting portion and the second connecting portion and the substrate in the insulating portion.
The power conversion device according to any one of claims 14 to 16, wherein at least one concave portion into which the at least one convex portion is individually fitted is formed on the other side of the intermediate portion and the substrate. .. The first erection is held in a state where at least one of the second capacitor and the third capacitor is held by the insulating portion and is arranged between the first erection portion and the second erection portion. The power conversion device according to any one of claims 14 to 17, which is electrically connected to the unit and the second erection unit. A plurality of the second capacitor and at least one of the third capacitors are provided.
The power conversion device according to claim 18, wherein a plurality of the second capacitor and the third capacitor are electrically connected in at least one form of series, parallel, and series-parallel, respectively.

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