Power conversion device

Abstract

A power conversion device includes: a first wiring (910) and a second wiring (920) connected to a power source (200); a first capacitor (520) connected to the first wiring and the second wiring; an electrical component (501) including a plurality of switches (511, 512) connected in parallel with the first capacitor via the first wiring and the second wiring; and a second capacitor (600) connected to one of the first wiring and the second wiring and connected to a reference potential section (700) with a constant potential, wherein the impedance of a first energizing path between the other side connection point (521, 522) of the first wiring and the power source, which is not through the first capacitor, is higher than the impedance of a second energizing path between the other side connection point and the second capacitor, which is through the first capacitor.

Description

[0001] Citation of relevant applications

[0002] This application is based on Japanese Patent Application No. 2020-152123, filed on September 10, 2020, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] The disclosure described in this specification relates to an electric power conversion device. Background Technology

[0004] In Patent Document 1, an inverter having a DC smoothing circuit connected to a battery, a three-phase AC conversion circuit connected to the DC smoothing circuit, and a smoothing capacitor is known.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2003-173952 Summary of the Invention

[0008] The DC smoothing circuit has two current paths connected to the battery. Each of these current paths contains a Y capacitor to remove current noise leaking from the three-phase AC converter circuit. Therefore, the number of components may increase.

[0009] The purpose of this invention is to provide a power conversion device that can suppress the increase in the number of components.

[0010] One aspect of the power conversion device disclosed herein has:

[0011] The first and second wirings connected to the power supply;

[0012] A first capacitor, wherein the first capacitor is connected to a first wiring and a second wiring;

[0013] Electrical components, including a plurality of switches connected in parallel with a first capacitor via a first wiring and a second wiring; and

[0014] The second capacitor is connected to one of the first wiring and the second wiring, and is also connected to a reference potential section with a constant potential.

[0015] The impedance of the first energizing path between the other side connection point of the first wiring and the second wiring, which is connected to the first capacitor, and the power source, which does not pass through the first capacitor, is higher than the impedance of the second energizing path between the other side connection point and the second capacitor, which passes through the first capacitor.

[0016] Therefore, the current noise generated on the first wiring side and the second wiring side, respectively, tends to flow to the second capacitor connected to one of the first wiring and the second wiring. Thus, even if the second capacitor is not connected separately to the first wiring and the second wiring, the current noise generated on the first wiring side and the second wiring side can be eliminated. This allows for a reduction in the number of components.

[0017] Furthermore, the reference numerals in the parentheses above only indicate the correspondence with the structures described in the embodiments described later, and do not limit the scope of the technology. Attached Figure Description

[0018] Figure 1 This is a circuit diagram representing an in-vehicle system.

[0019] Figure 2 This is a variation of the circuit diagram representing an onboard system.

[0020] Figure 3 This is a variation of the circuit diagram representing an onboard system.

[0021] Figure 4 This is a variation of the circuit diagram representing an onboard system. Detailed Implementation

[0022] Hereinafter, with reference to the accompanying drawings, various methods for implementing this disclosure will be described. In each method, sometimes the same reference numerals are used to denote parts corresponding to matters described in the preceding methods, and repeated descriptions are omitted. Where only a portion of the structure is described in each method, the previously described methods can be applied to the other parts of the structure.

[0023] Furthermore, not only combinations between parts that are explicitly shown to be specifically combinable in each embodiment, but also combinations between embodiments, embodiments and variations, and variations can be partially combined even without explicit indication, as long as they do not hinder the combination.

[0024] (First Implementation)

[0025] First, based on Figure 1 The following describes an on-board system 100 equipped with a power conversion device 300. This on-board system 100 constitutes a system for electric vehicles. The on-board system 100 includes a battery 200, a power conversion device 300, and an electric motor 400. The battery 200 acts as a power source. Furthermore, in the accompanying drawings, the battery 200 is abbreviated as "BATT".

[0026] Additionally, the vehicle system 100 has multiple ECUs (not shown). These ECUs are mounted on the base plate 800. These multiple ECUs send and receive signals to each other via bus wiring. The multiple ECUs cooperate to control the electric vehicle. Through the control of the multiple ECUs, the regeneration and power operation of the electric motor 400, corresponding to the SOC (State of Charge) of the battery 200, are controlled. SOC is an abbreviation for State of Charge. ECU is an abbreviation for Electronic Control Unit. Furthermore, in the accompanying drawings, the base plate 800 is abbreviated as "CB".

[0027] Battery 200 has multiple secondary cells. These multiple secondary cells form a battery pack connected in series. The state of charge (SOC) of this battery pack is equivalent to that of battery 200. Lithium-ion secondary cells, nickel-metal hydride secondary cells, and organic radical cells can be used as secondary cells.

[0028] <Power Conversion Device>

[0029] The power conversion device 300 includes an inverter 500 and a second capacitor 600. The power conversion device 300 performs power conversion between the battery 200 and the motor 400. The power conversion device 300 converts the direct current (DC) power from the battery 200 into alternating current (AC). The power conversion device 300 also converts the AC power generated by the electric motor 400 (regenerated power) into DC power.

[0030] Electric motor 400 is connected to the output shaft of an electric vehicle (not shown). The rotational energy of electric motor 400 is transmitted to the driving wheels of the electric vehicle via the output shaft. Conversely, the rotational energy of the driving wheels is transmitted to electric motor 400 via the output shaft.

[0031] The electric motor 400 operates powered by alternating current (AC) electricity supplied from the power conversion device 300. This provides propulsion to the driving wheels. Furthermore, the electric motor 400 regenerates power using rotational energy transferred from the driving wheels. The AC power generated by this regeneration is converted into direct current (DC) power by the power conversion device 300. This DC power is supplied to the battery 200. Additionally, the DC power is also supplied to various electrical loads installed in the electric vehicle.

[0032] <Inverter>

[0033] The inverter 500 includes an electrical component 501 and a first capacitor 520. The electrical component 501 includes a bridge branch group 510 composed of multiple switches. The inverter 500 is connected to a first power supply bus 910 and a second power supply bus 920, both of which are connected to the battery 200. The first power supply bus 910 is connected to the positive terminal of the battery 200. The second power supply bus 920 is connected to the negative terminal of the battery 200.

[0034] like Figure 1 As shown, an electrical component 501 and a first capacitor 520 are connected in parallel on the first power supply bus 910 and the second power supply bus 920. The first power supply bus 910 corresponds to the first wiring. The second power supply bus 920 corresponds to the second wiring.

[0035] The aforementioned bridge branch group 510 includes a U-phase bridge branch 513, a V-phase bridge branch 514, and a W-phase bridge branch 515. Each of these three-phase bridge branches has a first high-side switch 511 and a first low-side switch 512 as switches. Additionally, each of the three-phase bridge branches has a first high-side diode 511a and a first low-side diode 512a as diodes. The first high-side switch 511 and the first low-side switch 512 function as switches.

[0036] The cathode connection point of the first high-side diode 511a is connected to the collector of the first high-side switch 511. The anode connection point of the first high-side diode 511a is connected to the emitter of the first high-side switch 511. Thus, the first high-side diode 511a and the first high-side switch 511 are connected in reverse parallel.

[0037] The cathode connection point of the first low-side diode 512a is connected to the collector of the first low-side switch 512. The anode connection point of the first low-side diode 512a is connected to the emitter of the first low-side switch 512. Thus, the first low-side diode 512a and the first low-side switch 512 are connected in reverse parallel.

[0038] The switches and diodes included in each of the three-phase bridge branches are resin-sealed by a resin component (not shown). A portion of the collector terminal connected to the collector of the first high-side switch 511 is exposed from the resin component. A portion of the collector terminal is connected to the first power supply bus 910.

[0039] A portion of the emitter terminal connected to the emitter of the first low-side switch 512 is exposed from the resin component. A portion of the emitter terminal is connected to the second power supply bus 920.

[0040] A portion of the switch terminals, such as gate terminals or sensor terminals, which are connected to the gates of the first high-side switch 511 and the first low-side switch 512, are exposed from the resin component. The switch terminals are connected to the substrate 800.

[0041] A portion of the output terminal, which is connected to the emitter of the first high-side switch 511 and the collector of the first low-side switch 512, is exposed from the resin component.

[0042] The U-phase bus 410 is connected to the output terminals of the emitter of the first high-side switch 511 and the collector of the first low-side switch 512, which are respectively connected to the U-phase bridge branch 513. The U-phase bus 410 is connected to the U-phase stator coil of the motor 400.

[0043] The V-phase bus 420 is connected to the output terminals of the emitter of the first high-side switch 511 and the collector of the first low-side switch 512 included in the V-phase bridge branch 514, respectively. The V-phase bus 420 is connected to the V-phase stator coil of the motor 400.

[0044] The W-phase bus 430 is connected to the output terminals of the emitter of the first high-side switch 511 and the collector of the first low-side switch 512 included in the W-phase bridge branch 515, respectively. The W-phase bus 430 is connected to the W-phase stator coil of the motor 400.

[0045] In this embodiment, an N-channel IGBT is used as the switch. However, MOSFETs can also be used instead of IGBTs as these switches. When using MOSFETs as switches, diodes may not be necessary.

[0046] These switches can be manufactured from semiconductors such as Si and wide-bandgap semiconductors such as SiC. There are no particular limitations on the constituent materials of semiconductor elements.

[0047] <The First Capacitor>

[0048] The first capacitor 520 is a smoothing capacitor that smooths the pulsating current generated when rectifying AC to DC.

[0049] The first capacitor 520 has two electrodes. One of these electrodes is connected to the first power supply bus 910 at the first capacitor connection point 521. The other of these electrodes is connected to the second power supply bus 920 at the second capacitor connection point 522.

[0050] <Second Capacitor>

[0051] The second capacitor 600 is a filter capacitor used to remove current noise flowing through the first power supply bus 910 and the second power supply bus 920. These power supply buses carry high-frequency current noise generated by the inverter 500, current noise caused by electromagnetic noise intruding into the power supply buses, and other noise.

[0052] The second capacitor 600 has two electrodes. One of these electrodes is connected to the first power supply bus 910 at the third capacitor connection point 601. The other electrode is connected to the vehicle body 700 at the fourth capacitor connection point 602. Alternatively, the fourth capacitor connection point 602 may not be connected to the vehicle body 700, as long as the second capacitor 600 is connected to a reference potential with a constant potential. The vehicle body 700 serves as the reference potential section.

[0053] In addition, the electrostatic capacitance of the second capacitor 600 is larger than the parasitic capacitance of the battery 200.

[0054] <First Power Supply Bus and Second Power Supply Bus>

[0055] As explained so far, electrical component 501 and first capacitor 520 are connected in parallel to the first power supply bus 910 and the second power supply bus 920. The first power supply bus 910 is connected to the positive terminal of battery 200. The second power supply bus 920 is connected to the negative terminal of battery 200.

[0056] The first capacitor connection point 521, to which the first capacitor 520 in the first power supply bus 910 is connected, is located between the first connection point 931 of the first power supply bus 910 connected to the battery 200 and the second connection point 932 of the first power supply bus 910 connected to the electrical component 501. The first capacitor connection point 521 is equivalent to a one-sided connection point.

[0057] The second capacitor connection point 522, to which the first capacitor 520 in the second power supply bus 920 is connected, is located between the third connection point 941 of the second power supply bus 920 connected to the battery 200 and the fourth connection point 942 of the second power supply bus 920 connected to the electrical component 501. The second capacitor connection point 522 corresponds to the connection point on the other side.

[0058] For ease of explanation, the portion between the first connection point 931 and the first capacitor connection point 521 in the first power supply bus 910 will be referred to as the first transmission portion 911. The portion between the first capacitor connection point 521 and the second connection point 932 in the first power supply bus 910 will be referred to as the second transmission portion 912. Furthermore, the first connection point 931 corresponds to the third connection point.

[0059] Similarly, the portion between the third connection point 941 and the second capacitor connection point 522 in the second power supply bus 920 is designated as the third transmission portion 921. The portion between the second capacitor connection point 522 and the fourth connection point 942 in the second power supply bus 920 is designated as the fourth transmission portion 922. Furthermore, the third connection point 941 corresponds to the first connection point. The fourth connection point 942 corresponds to the second connection point.

[0060] <Connection point of the second capacitor>

[0061] like Figure 1 As shown, in this embodiment, the connection point of the second capacitor 600 connected to the first power supply bus 910 is located at the first transmission section 911 of the first power supply bus 910. For ease of explanation, the connection point of the second capacitor 600 connected to the first power supply bus 910 is referred to as the third capacitor connection point 601.

[0062] In other words, the third capacitor connection point 601 is located between the first connection point 931 and the first capacitor connection point 521. Alternatively, the third capacitor connection point 601 may also be located at the second transmission section 912.

[0063] Alternatively, the second capacitor 600 can also be connected to the second power supply bus 920. In this case, the second capacitor 600 is connected to either the third transmission section 921 or the fourth transmission section 922 of the second power supply bus 920. In this case, the third capacitor connection point 601 is located at either the third transmission section 921 or the fourth transmission section 922.

[0064] <Current Noise and Impedance>

[0065] As described above, the electrical component 501 has multiple switches. DC power is converted to AC power and vice versa by PWM control of these switches. Due to this PWM control, high-frequency current noise is generated from the multiple switches. This current noise flows from the electrical component 501 to the second transmission section 912 and the fourth transmission section 922, respectively.

[0066] The frequency of this current noise is higher than the AC power flowing through the first power supply bus 910 and the second power supply bus 920. In the frequency band of this current noise, the impedance of the first energized path 901 between the second capacitor connection point 522 and the third connection point 941 is higher than the impedance of the second energized path 902 between the second capacitor connection point 522 and the third capacitor connection point 601.

[0067] Due to the magnitude of the impedance, the impedance of the first capacitor 520 is naturally lower than the impedance of the first energized path 901.

[0068] In the frequency band of this current noise, the impedance of the third energizing path 903 between the first capacitor connection point 521 and the third capacitor connection point 601 is lower than the impedance of the fourth energizing path 904 between the first capacitor connection point 521 and the third connection point 941.

[0069] The first power path 901 to the fourth power path 904 shown above are in Figure 1 The arrowhead is indicated by a solid line. For example... Figure 1 As shown, the first energizing path 901 includes a third transmission section 921. The second energizing path 902 includes a first capacitor 520 and a portion of the first transmission section 911. The third energizing path 903 includes a portion of the first transmission section 911. The fourth energizing path 904 includes a first capacitor 520 and the third transmission section 921.

[0070] <Components of an Electricity Conversion Device>

[0071] In addition to the circuit components described so far, the power conversion device 300 also includes a housing 502. The inverter 500 is housed within the housing 502. Figure 1 As shown, a portion of the first transmission section 911 and a portion of the third transmission section 921 protrude from the housing 502. A second capacitor 600 is connected to a portion of the first transmission section 911 protruding from the housing 502. The second capacitor 600 is disposed outside the housing 502.

[0072] A portion of the first transmission section 911 exposed from the housing 502 is covered by a shielding section 940 made of a component with high magnetic permeability. The shielding section 940 covers the first transmission section 911 exposed from the housing 502, thereby easily suppressing electromagnetic noise from the outside from entering the first transmission section 911.

[0073] <Effects>

[0074] As explained so far, in the current noise frequency band, the impedance of the first energized path 901 is higher than that of the second energized path 902. Therefore, the current noise generated by the electrical component 501 on the second power supply bus 920 side is more likely to flow to the second energized path 902 than that generated by the first energized path 901.

[0075] Furthermore, in the current noise frequency band, the impedance of the third energizing path 903 is lower than that of the fourth energizing path 904. Therefore, compared to the fourth energizing path 904, the current noise generated by the electrical component 501 on the first power supply bus 910 side is more likely to pass through the third energizing path 903.

[0076] As described above, a portion of the first transmission section 911 is included in the second power path 902 and the third power path 903. The second capacitor 600 is connected to a portion of the first transmission section 911 at the third capacitor connection point 601.

[0077] As a result, the current noise generated on the first power supply bus 910 side and the second power supply bus 920 side of the electrical component 501 can easily flow to the second capacitor 600.

[0078] Therefore, even if the second capacitor 600 is not individually connected to the first power supply bus 910 and the second power supply bus 920 respectively, it is possible to remove current noise generated on the first power supply bus 910 side and the second power supply bus 920 side of the electrical component 501. As a result, the number of components can be reduced.

[0079] As explained so far, the second capacitor 600 is disposed outside the housing 502. This makes it difficult to restrict the arrangement of the electrical component 501 and the first capacitor 520 inside the housing 502. It easily increases the design freedom of the electrical component 501 and the first capacitor 520 inside the housing 502.

[0080] As explained so far, the electrostatic capacitance of the second capacitor 600 is larger than the parasitic capacitance of the battery 200. Therefore, current noise flowing through the first transmission section 911 can be easily removed by the second capacitor 600.

[0081] (First variation)

[0082] like Figure 2 As shown, in addition to the bridge branch group 510, the electrical component 501 may also include a reactor 530, a connecting busbar 531, an A-phase bridge branch 518, and a third capacitor 540. The A-phase bridge branch 518 includes two second high-side switches 516 and a second low-side switch 517 connected in series. The second high-side switch 516 is equivalent to an auxiliary switch.

[0083] In addition to the first transmission section 911 and the second transmission section 912, the first power supply bus 910 also has a fifth transmission section 913 connected to the second transmission section 912 via a reactor 530 and a second high-side switch 516. Furthermore, the reactor 530 and the second high-side switch 516 constitute a portion of the first power supply bus 910 that connects the second transmission section 912 and the fifth transmission section 913.

[0084] like Figure 2 As shown, one end of reactor 530 is connected to one end of the second transmission section 912. The other end of reactor 530 is connected to one end of connecting bus 531. The other end of connecting bus 531 is connected to the midpoint of the second high-side switch 516 and the second low-side switch 517 included in the A-phase bridge branch 518. Furthermore, the connection point between one end of the second transmission section 912 and one end of reactor 530 corresponds to the second connection point 932.

[0085] Furthermore, the collector of the second high-side switch 516 is connected to the fifth transmission section 913. The emitter of the second low-side switch 517 is connected to the fourth transmission section 922. The emitter of the second high-side switch 516 is connected to the collector of the second low-side switch 517. Thus, the second high-side switch 516 and the second low-side switch 517 are connected in series from the fifth transmission section 913 toward the fourth transmission section 922.

[0086] At the fifth transmission section 913 and the fourth transmission section 922, in addition to the A-phase bridge branch 518, a third capacitor 540 and the aforementioned bridge branch group 510 are also connected. The A-phase bridge branch 518, the third capacitor 540, and the bridge branch group 510 are connected in parallel between the fifth transmission section 913 and the fourth transmission section 922. The bridge branch group 510 is connected to the fifth transmission section 913 at the first switch connection point 551. The bridge branch group 510 is connected to the fourth transmission section 922 at the second switch connection point 552.

[0087] The third capacitor 540 has two electrodes. One of these electrodes is connected to the fifth transmission section 913 at the fifth capacitor connection point 541. The other of these electrodes is connected to the fourth transmission section 922 at the sixth capacitor connection point 542.

[0088] The impedance between the fifth capacitor connection point 541 and the first connection point 931 is likely to be higher than the impedance between the fifth capacitor connection point 541 and the third connection point 941 via the third capacitor 540.

[0089] Therefore, the current noise generated on the fifth transmission section 913 side of the bridge branch group 510 can easily flow to the fourth transmission section 922 through the third capacitor 540.

[0090] Furthermore, current noise generated at the fourth transmission section 922 of the bridge branch group 510 also tends to flow to the fourth transmission section 922. As described above, the first capacitor 520 is connected to the second power supply bus 920 at the second capacitor connection point 522. Current noise generated in the bridge branch group 510 tends to pass through the fourth transmission section 922 and flow to the second capacitor connection point 522.

[0091] As explained so far, in the current noise band, the impedance of the first energized path 901 is higher than that of the second energized path 902. Current noise flowing through the second capacitor connection point 522 is more likely to flow to the second energized path 902 than to the first energized path 901.

[0092] As a result, current noise tends to flow to the second capacitor 600. Even if the second capacitor 600 is not separately connected to the first power supply bus 910 and the second power supply bus 920, it can still remove the current noise generated in the bridge branch group 510.

[0093] (Second variation)

[0094] In the first variation, such as Figure 2The diagram illustrates how the third capacitor connection point 601 is located between the first connection point 931 and the first capacitor connection point 521. However, it is also possible to maintain the circuit structure described in the first modified example while... Figure 3 As shown, the third capacitor connection point 601 is positioned between the second capacitor connection point 522 and the sixth capacitor connection point 542.

[0095] In this situation, the current noise generated in the aforementioned bridge branch group 510 and A-phase bridge branch 518 and flowing towards the fourth transmission section 922 easily flows through the third capacitor connection point 601 before passing through the second capacitor connection point 522. The current noise can be removed by the second capacitor 600 before passing through the second capacitor connection point 522.

[0096] Additionally, the first energizing path 901 includes a first transmission section 911. The second energizing path 902 includes a first capacitor 520 and a portion of a fourth transmission section 922. The second capacitor connection point 522 corresponds to a connection point on one side. Correspondingly, the first capacitor connection point 521 corresponds to a connection point on the other side. The first connection point 931 corresponds to a first connection point. The second connection point 932 corresponds to a second connection point. The third connection point 941 corresponds to a third connection point. The first switch connection point 551 corresponds to a switch connection point on the other side. The second switch connection point 552 corresponds to a switch connection point on one side.

[0097] As mentioned so far, the impedance of the first energizing path 901 is higher than that of the second energizing path 902. Therefore, even if the current noise generated at the fifth transmission section 913 of the bridge branch group 510 and the A-phase bridge branch 518 flows to the first capacitor connection point 521, it is more likely to flow to the second energizing path 902 than to the first energizing path 901.

[0098] As a result, the current noise tends to flow to the second capacitor 600. Even if the second capacitor 600 is not separately connected to the first power supply bus 910 and the second power supply bus 920, it is able to remove the current noise generated in the bridge branch group 510 and the A-phase bridge branch 518.

[0099] Alternatively, although not shown, the second capacitor 600 may also be located between the third connection point 941 and the second capacitor connection point 522. In this case, the second energizing path 902 includes a portion of the first capacitor 520 and the third transmission section 921.

[0100] (Third variation)

[0101] In addition to the circuit components described so far, the power conversion device 300 also includes, for example: Figure 4As shown, it also includes a resistor 801 and a discharge resistor 950. Resistor 801 is mounted on the base plate 800 along with the aforementioned ECU. Discharge resistor 950 is connected to the first power supply bus 910 and the second power supply bus 920. The impedance of resistor 801 is higher than the impedance of discharge resistor 950.

[0102] like Figure 4 As shown, in addition to the ECU and resistor 801, a second capacitor 600 is also mounted on the substrate 800. The second capacitor 600 is connected to resistor 801.

[0103] In addition to the transmission section described so far, the first power supply bus 910 also has a substrate transmission section 914 connected to the substrate 800. The substrate transmission section 914 is connected to the second capacitor 600 and the resistor 801, respectively. Therefore, the current noise generated from the bridge branch group 510 flows through the second capacitor 600 and the resistor 801, respectively.

[0104] As mentioned above, the impedance of resistor 801 is higher than that of discharge resistor 950. Therefore, current noise is more likely to actively flow to the second capacitor 600 side compared to the resistor 801 side. This allows for a reduction in the capacitance of the second capacitor 600, making it easier to reduce its size.

[0105] In addition, although not shown in the figure, the inverter 500 may include the A-phase bridge branch 518 and reactor 530, in addition to the bridge branch group 510 and the first capacitor 520.

[0106] (Other variations)

[0107] In this embodiment, an example is shown where the power conversion device 300 is included in an on-board system 100 for an electric vehicle. However, the application of the power conversion device 300 is not particularly limited to the example described above. For example, a structure in which the power conversion device 300 is included in a hybrid power system including an electric motor 400 and an internal combustion engine may also be adopted.

[0108] In this embodiment, an example of one motor 400 connected to the power conversion device 300 is shown. However, a structure in which multiple motors 400 are connected to the power conversion device 300 can also be used. In this case, the power conversion device 300 has multiple three-phase switching modules for constituting the inverter 500.

[0109] While this disclosure has been described based on embodiments, it should be understood that this disclosure is not limited to the above embodiments and structures. This disclosure also includes various modifications and equivalent variations. Furthermore, although various combinations and arrangements are shown in this disclosure, further combinations and arrangements of only a single element, or more or less thereof, also fall within the scope and spirit of this disclosure.

Claims

1. A power conversion device, comprising: The first and second wirings connected to the power supply; A first capacitor is connected to the first wiring and the second wiring; An electrical component, the electrical component including a plurality of switches connected in parallel with the first capacitor via the first wiring and the second wiring; The second capacitor is connected to one of the first wiring and the second wiring, and is also connected to a reference potential section with a constant potential. as well as A housing that houses the electrical components and the first capacitor. The impedance of the first power-carrying path is higher than the impedance of the second power-carrying path. The first power-carrying path is the path between the other side connection point of the first wiring and the second wiring (connected to the first capacitor) and the power source, without passing through the first capacitor. The second power-carrying path is the path between the other side connection point and the second capacitor, passing through the first capacitor. The second capacitor is disposed outside the housing.

2. A power conversion device, comprising: The first and second wirings connected to the power supply; A first capacitor is connected to the first wiring and the second wiring; An electrical component, the electrical component including a plurality of switches connected in parallel with the first capacitor via the first wiring and the second wiring; The second capacitor is connected to one of the first wiring and the second wiring, and is also connected to a reference potential section with a constant potential. A substrate, the substrate including a portion of one of the first wiring and the second wiring; A resistor, which is mounted on the substrate and has one end connected to one of the first wiring and the second wiring; as well as A discharge resistor, which is connected to the first wiring and the second wiring. The impedance of the first power-carrying path is higher than the impedance of the second power-carrying path. The first power-carrying path is the path between the other side connection point of the first wiring and the second wiring (connected to the first capacitor) and the power source, without passing through the first capacitor. The second power-carrying path is the path between the other side connection point and the second capacitor, passing through the first capacitor. The impedance of the resistor is higher than the impedance of the discharge resistor. The second capacitor is mounted on the substrate and connected to a portion of either the first wiring or the second wiring included in the substrate.

3. The power conversion device as described in claim 1 or 2, characterized in that, The other connection point is located between the first connection point and the second connection point. The first connection point connects the other of the first wiring and the second wiring to the power supply, and the second connection point connects the other of the first wiring and the second wiring to the electrical component.

4. The power conversion device as described in claim 3, characterized in that, The third capacitor connection point of one of the first wiring and the second wiring, which is connected to the second capacitor, is located between the third connection point and the first-side connection point. The third connection point connects one of the first wiring and the second wiring to the power supply, and the first-side connection point connects one of the first wiring and the second wiring to the first capacitor.

5. The power conversion device as described in claim 4, characterized in that, In addition to the plurality of switches, the electrical components also include reactors and auxiliary switches arranged from one side connection point toward one side switch connection point, the one side switch connection point connecting one of the first wiring and the second wiring to the plurality of switches.

6. The power conversion device as described in claim 3, characterized in that, In addition to the plurality of switches, the electrical components also include reactors and auxiliary switches arranged from the other side connection point toward the other side switch connection point, the other side switch connection point connecting the other side of the first wiring and the second wiring to the plurality of switches.

7. The power conversion device as described in claim 1 or 2, characterized in that, The electrostatic capacitance of the second capacitor is larger than the parasitic capacitance of the power source.

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