Capacitor module and power conversion device

Abstract

A Y capacitor (40) includes capacitors (41, 42) connected in parallel between a power source conductor (20) and a base conductor (30). The capacitor (41) is mounted spaced apart from a location of connection with the power source conductor (20) on a coupling conductor (51), and constitutes a path (R1) along with the coupling conductor (51). The capacitor (42) is mounted spaced apart from a location of connection with the power source conductor (20) on a coupling conductor (52), and constitutes a path (R2) along with the coupling conductor (52). The paths (R1, R2) are cross-connected between the power source conductor (20) and the base conductor (30). The power source conductor (20) has connection sections (P1, N1) for connection with the path (R1), and connection sections (P2, N2) for connection with the path (R2) that is provided to a location close to an inverter (5). The base conductor (30) comprises a connecting section (B1) for connection with the path (R2), and a connecting section (B2) for connection with the path (R2) that is provided to a location spaced apart from the connection section (B1) so that there is an impedance between the connection section (B1) and the connecting section (B2).

Description

Capacitor Module and Power Conversion Device Cross - Reference to Related Applications

[0001] This application is based on Japanese Patent Application No. 2024 - 193338 filed in Japan on November 4, 2024, the content of which is incorporated herein by reference in its entirety.

[0002] The disclosure in this specification relates to a capacitor module and a power conversion device.

[0003] Patent Document 1 discloses a Y - capacitor. The description of the prior art document is incorporated herein by reference as an explanation of the technical elements in this specification.

[0004] Japanese Patent Application Laid - Open No. 2023 - 143709

[0005] The Y - capacitor includes two capacitors. The series circuit of the two capacitors is connected between the positive - side wiring line and the negative - side wiring line which are power conductors. The nodes of the two capacitors are connected to the ground potential which is the reference potential. When current flows, the power conductors generate heat. The heat of the power conductors affects the Y - capacitor. The heat of the power conductors causes, for example, shortening of the life of the Y - capacitor and deterioration of performance.

[0006] When the Y - capacitor is arranged at a position away from the power conductors to reduce the influence of heat, the impedance between the power conductors and the Y - capacitor increases, and the effect of the Y - capacitor decreases. From the above viewpoints or other viewpoints not mentioned, further improvements are required for the capacitor module and the power conversion device.

[0007] One object of the present disclosure is to provide a capacitor module and a power conversion device that can improve the effect of the Y - capacitor while reducing the heat influence.

[0008] A capacitor module in one aspect of the disclosure is a capacitor module connected to a power converter including a switching element, comprising: a positive electrode conductor connected to the DC positive electrode of the power converter; a negative electrode conductor connected to the DC negative electrode of the power converter; a base conductor connected to a grounding member that provides a reference potential; a Y capacitor including a first capacitor and a second capacitor connected in series between the positive electrode conductor and the negative electrode conductor, and connected in parallel between a power supply conductor which is at least one of the positive electrode conductor and the negative electrode conductor and the base conductor; a first connecting conductor electrically connected to the power supply conductor, with the first capacitor mounted at a position away from the connection point with the power supply conductor, and constituting a first path together with the first capacitor; a second connecting conductor electrically connected to the power supply conductor, with the second capacitor mounted at a position away from the connection point with the power supply conductor, and constituting a second path together with the second capacitor, wherein the first path and the second path are cross-connected between the power supply conductor and the base conductor. The power conductor has a first power connection to which a first path is connected, and a second power connection located closer to the power converter than the first power connection and to which a second path is connected. The base conductor has a first base connection to which a second path is connected, and a second base connection located away from the first base connection and to which the first path is connected, such that an impedance exists between the first base connection and the first base connection.

[0009] According to the disclosed capacitor module, the first and second Y-capacitors are positioned away from the power supply conductor. This reduces the effect of heat from the power supply conductor on the Y-capacitors. Furthermore, an impedance exists between the first and second base connections. Through cross-connection, the impedance between the first and second base connections, together with the impedance between the first and second power supply connections, the impedance of the first path, and the impedance of the second path, forms a Wheatstone bridge circuit. Therefore, by adjusting each impedance, the impedance of the first and second paths can be reduced, ideally to zero. Even while positioning the Y-capacitors away from the power supply conductor, the effect of the Y-capacitors can be improved by canceling out the impedances.

[0010] Another aspect of the disclosure is a power converter comprising: a power converter including a switching element; and a capacitor module connected to the power converter, wherein the capacitor module comprises: a positive conductor connected to the DC positive terminal of the power converter; a negative conductor connected to the DC negative terminal of the power converter; a base conductor connected to a grounding member that provides a reference potential; a Y capacitor including a first capacitor and a second capacitor connected in series between the positive and negative conductors and connected in parallel between a power supply conductor which is at least one of the positive and negative conductors and the base conductor; a first connecting conductor electrically connected to the power supply conductor, with the first capacitor mounted at a position away from the connection point with the power supply conductor, and constituting a first path together with the first capacitor; and a second connecting conductor electrically connected to the power supply conductor, with the second capacitor mounted at a position away from the connection point with the power supply conductor, and constituting a second path together with the second capacitor, wherein the first path and the second path are cross-connected between the power supply conductor and the base conductor. The power conductor has a first power connection to which a first path is connected, and a second power connection located closer to the power converter than the first power connection and to which a second path is connected. The base conductor has a first base connection to which a second path is connected, and a second base connection located away from the first base connection and to which the first path is connected, such that an impedance exists between the first base connection and the first base connection.

[0011] According to the disclosed power conversion device, the first and second capacitors, which are Y-capacitors, are placed at a distance from the power supply conductor. This reduces the effect of heat from the power supply conductor on the Y-capacitors. Furthermore, an impedance exists between the first and second base connections. Through cross-connection, the impedance between the first and second base connections, together with the impedance between the first and second power supply connections, the impedance of the first path, and the impedance of the second path, forms a Wheatstone bridge circuit. Therefore, by adjusting each impedance, the impedance of the first and second paths can be reduced, ideally to zero. Even while placing the Y-capacitors at a distance from the power supply conductor, the effect of the Y-capacitors can be improved by canceling out the impedances.

[0012] The various embodiments disclosed in this specification employ different technical means to achieve their respective objectives. The reference numerals in parentheses in the claims are illustrative in their correspondence with the embodiments described later and are not intended to limit the technical scope. The objectives, features, and effects disclosed in this specification will become clearer by referring to the subsequent detailed description and the accompanying drawings.

[0013] This figure shows an example of a capacitor module, power converter, and drive system according to the first embodiment. This figure illustrates the propagation path of common-mode noise. This is a circuit diagram showing a capacitor module. This figure shows a Wheatstone bridge circuit provided by the capacitor module. This figure shows an example of the structure of a capacitor module. This figure shows an example of the fixing structure of the base conductor. This figure shows another example of the fixing structure of the base conductor. This figure shows another example of the fixing structure of the base conductor. This figure shows another example of the fixing structure of the base conductor. This figure shows another example of the fixing structure of the base conductor. This figure shows a modified example of the structure of a capacitor module. This figure shows a modified example of the structure of a capacitor module. This figure shows a modified example of the structure of a capacitor module. This figure shows a circuit diagram showing an example of a capacitor module according to the second embodiment. This circuit diagram shows an example of a capacitor module according to the third embodiment. This circuit diagram shows an example of a capacitor module according to the fourth embodiment. This circuit diagram shows an example of a capacitor module according to the fifth embodiment. This figure shows a modified example.

[0014] Several embodiments will be described below with reference to the drawings. In each embodiment, the same reference numerals are used for corresponding components, and redundant explanations may be omitted. If only a part of the configuration is described in each embodiment, the configuration of other embodiments described earlier can be applied to the other parts of that configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations from multiple embodiments can be partially combined even if not explicitly stated, as long as there are no particular problems with the combination.

[0015] (First Embodiment) The capacitor module and power conversion device equipped with the capacitor module of this embodiment are applied, for example, to a mobile body that uses a rotating electric machine as a drive source. The mobile body is, for example, an electric vehicle such as an electric vehicle (BEV), a hybrid electric vehicle (HEV), or a plug-in hybrid electric vehicle (PHEV), an electric aircraft such as a drone or an electric vertical take-off and landing aircraft (eVTOL), a ship, construction machinery, or agricultural machinery. BEV is an abbreviation for Battery Electric Vehicle. HEV is an abbreviation for Hybrid Electric Vehicle. eVTOL is an abbreviation for electronic Vertical Take-Off and Landing aircraft. Examples of application to vehicles will be described below.

[0016] <Vehicle Drive System> Figure 1 shows an example of a capacitor module, power converter, and drive system according to this embodiment. The vehicle drive system 1 includes a DC power supply 2, a motor generator 3, and a power converter 4.

[0017] The DC power supply 2 is a DC voltage source configured to supply DC power. The DC power supply 2 is composed of, for example, a rechargeable secondary battery. The secondary battery is, for example, a lithium-ion battery or a nickel-metal hydride battery. The motor generator 3 is a three-phase AC rotating electric machine. The motor generator 3 functions as the vehicle's driving source, i.e., an electric motor. The motor generator 3 functions as a generator during regeneration. The power converter 4 performs power conversion between the DC power supply 2 and the motor generator 3. The power generated by the motor generator 3 is supplied to, for example, the DC power supply 2 via the power converter 4. This charges the DC power supply 2.

[0018] The drive system 1 may include a power supply switch, such as an SMR (System Main Relay), between the DC power supply 2 and the power converter 4. SMR is an abbreviation for System Main Relay. For example, turning the power supply switch on enables power supply from the DC power supply 2 to the motor generator 3, and turning the power supply switch off cuts off the power supply from the DC power supply 2 to the motor generator 3.

[0019] <Power Conversion Device> Figure 1 shows an example of a power conversion device 4. The example power conversion device 4 includes an inverter 5, a capacitor module 6, a smoothing capacitor 7, and a housing 8.

[0020] The inverter 5 converts the DC voltage to a three-phase AC voltage according to the switching control of the control circuit and outputs it to the motor generator 3. This drives the motor generator 3 to generate a predetermined torque. During regenerative braking of the vehicle, the inverter 5 converts the three-phase AC voltage generated by the motor generator 3 in response to the rotational force from the wheels to a DC voltage according to the switching control of the control circuit and outputs it to the DC power supply. In this way, the inverter 5 performs bidirectional power conversion between the DC power supply 2 and the motor generator 3. The inverter 5 is sometimes referred to as a power converter, power conversion module, or power module. Because the inverter 5 has semiconductor elements, that is, switching elements formed on a semiconductor substrate, it is sometimes referred to as a semiconductor module.

[0021] The inverter 5 comprises a power supply conductor 10, which consists of a positive conductor 10P and a negative conductor 10N, and an upper and lower arm circuit 11. The power supply conductor 10 forms part of the DC bus that is electrically connected to the DC power supply 2. The positive conductor 10P forms part of the high-potential DC bus (P bus) that is connected to the positive terminal of the DC power supply 2. The negative conductor 10N forms part of the low-potential DC bus (N bus) that is connected to the negative terminal of the DC power supply 2.

[0022] The upper and lower arm circuit 11 is connected to the positive conductor 10P and the negative conductor 10N. The upper and lower arm circuit 11 has an upper arm 11H and a lower arm 11L. The upper arm 11H and the lower arm 11L are connected in series between the positive conductor 10P and the negative conductor 10N, with the upper arm 11H on the positive conductor 10P side. The inverter 5 is configured to have three phases of upper and lower arm circuits 11. The upper and lower arm circuits 11 are sometimes referred to as legs. The connection point (node) between the upper arm 11H and the lower arm 11L is connected to the winding 3a of the corresponding phase in the motor generator 3 via the output conductor 12. The positive conductor 10P, the negative conductor 10N, and the output conductor 12 may be, for example, busbars made of metal plate material, or metal conductors (wiring patterns) arranged on an insulating substrate.

[0023] The inverter 5 has six arms. Each arm contains a switching element 13. The number of switching elements 13 constituting each arm is not particularly limited. There may be one or more. In the case of multiple switching elements 13, which are connected in parallel to each other, are turned on and off at the same timing by a common gate drive signal (drive voltage).

[0024] The example switching element 13 is an n-channel type MOSFET. MOSFET is an abbreviation for Metal Oxide Semiconductor Field Effect Transistor. In the upper arm 11H, the drain terminal of the MOSFET is connected to the positive conductor 10P. In the lower arm 11L, the source terminal of the MOSFET is connected to the negative conductor 10N. The source terminal of the MOSFET in the upper arm 11H and the drain of the MOSFET in the lower arm 11L are interconnected.

[0025] Each MOSFET has a freewheeling diode 14 connected in antiparallel. Diode 14 may be a parasitic diode (body diode) of the MOSFET, or it may be a separate diode. The anode terminal of diode 14 is connected to the source terminal of the corresponding MOSFET, and the cathode terminal is connected to the drain terminal.

[0026] Note that the switching element 13 is not limited to a MOSFET. For example, an IGBT may be used. IGBT is an abbreviation for Insulated Gate Bipolar Transistor. In the case of an IGBT, a freewheeling diode is also connected in antiparallel.

[0027] The smoothing capacitor 7 primarily smooths the DC voltage supplied from the DC power supply 2. The smoothing capacitor 7 is connected to the P bus and N bus as described above. The positive terminal of the smoothing capacitor 7 is connected to the P bus between the DC power supply 2 and the inverter 5. The negative terminal of the smoothing capacitor 7 is connected to the N bus between the DC power supply 2 and the inverter 5.

[0028] The housing 8 houses the other elements that constitute the power converter 4. The housing 8 includes metal components and is electrically connected to the body ground (GND), which is the reference potential of the vehicle. The housing 8 provides the case ground, which is the reference potential of the power converter 4. The housing 8 may be a metal housing formed using, for example, a metal material, or it may include an electrical insulating material such as resin and metal components.

[0029] The capacitor module 6 reduces high-frequency noise current, i.e., high-frequency noise, associated with the switching operation of the power converter. The example capacitor module 6 reduces high-frequency noise associated with the switching operation of the inverter 5. The capacitor module 6 reduces common-mode noise. In addition to common-mode noise, the capacitor module 6 can reduce normal-mode noise. Normal-mode noise is sometimes referred to as differential-mode noise. High frequency refers to, for example, several hundred kHz to several hundred MHz.

[0030] The capacitor module 6 comprises a positive conductor 20P and a negative conductor 20N, which are power supply conductors 20, a base conductor 30, a Y capacitor 40, and a connecting conductor 50. The positive conductor 20P, the negative conductor 20N, the base conductor 30, and the connecting conductor 50 may be, for example, busbars made of metal plate material, or metal conductors (wiring patterns) arranged on an insulating substrate.

[0031] The power conductor 20 forms part of the DC bus. The positive electrode conductor 20P forms part of the P bus. The negative electrode conductor 20N forms part of the N bus. The base conductor 30 is connected to a grounding member that provides a reference potential. In this example, the base conductor 30 is connected to the housing 8, which is the grounding member. The base conductor 30 is electrically connected to the body ground via the housing 8. The base conductor 30 may also be electrically connected to the body ground via a grounding member other than the housing 8.

[0032] The positive conductor 20P has positive terminals 21P and 22P. Positive terminal 21P is the terminal on the DC power supply 2 side, and positive terminal 22P is the terminal on the inverter 5 side. Positive terminal 21P is connected to the positive terminal of the DC power supply 2. Positive terminal 22P is connected to the positive terminal 15P of the positive conductor 10P. The negative conductor 20N has negative terminals 21N and 22N. Negative terminal 21N is the terminal on the DC power supply 2 side, and negative terminal 22N is the terminal on the inverter 5 side. Negative terminal 21N is connected to the negative terminal of the DC power supply 2. Negative terminal 22N is connected to the negative terminal 15N of the negative conductor 10N. Positive terminal 15P corresponds to the DC positive terminal of the power converter, and negative terminal 15N corresponds to the DC negative terminal.

[0033] The Y capacitor 40 has multiple capacitors connected in series between the positive conductor 20P and the negative conductor 20N. The Y capacitor 40 also has multiple capacitors connected in parallel between at least one of the power supply conductors 20 and the base conductor 30. The example Y capacitor 40 has capacitors 41 and 42 connected in parallel between the power supply conductor 20 and the base conductor 30. The capacitances of all capacitors 41 and 42 are approximately equal to each other. Capacitor 41 corresponds to the first capacitor, and capacitor 42 corresponds to the second capacitor. Note that the capacitances of capacitors 41 and 42 may be different from each other.

[0034] Capacitor 41 includes capacitor 41H and capacitor 41L. Capacitor 42 includes capacitor 42H and capacitor 42L. Capacitors 41H and 42H are located on the positive conductor 20P side, and capacitors 41L and 42L are located on the negative conductor 20N side. Capacitors 41H and 41L are connected in series between the positive conductor 20P and the negative conductor 20N. Capacitors 42H and 42L are connected in series between the positive conductor 20P and the negative conductor 20N. Capacitors 41H and 42H are connected in parallel between the positive conductor 20P and the base conductor 30. Capacitors 41L and 42L are connected in parallel between the negative conductor 20N and the base conductor 30.

[0035] The connecting conductor 50, together with the Y capacitor 40, constitutes a path connecting the positive conductor 20P and the negative conductor 20N. The connecting conductor 50 also constitutes a path connecting the power supply conductor 20 and the base conductor 30. In this way, the connecting conductor 50, together with the Y capacitor 40, constitutes a bypass for the P bus and the N bus. The connecting conductor 50 is a branch line connected to the DC bus. The example connecting conductor 50 has connecting conductors 51 and 52. The connecting conductor 51, together with the capacitor 41 mounted on the connecting conductor 51, constitutes path R1. The connecting conductor 52, together with the capacitor 42 mounted on the connecting conductor 52, constitutes path R2. The connecting conductor 51 corresponds to the first connecting conductor, and the connecting conductor 52 corresponds to the second connecting conductor. Path R1 corresponds to the first path, and path R2 corresponds to the second path.

[0036] The connecting conductor 51 includes connecting conductor 51H and connecting conductor 51L. The connecting conductor 52 includes connecting conductor 52H and connecting conductor 52L. Path R1 includes path R1H and path R1L. Path R2 includes path R2H and path R2L. Connecting conductors 51H and 52H are located on the positive electrode conductor 20P side, and connecting conductors 51L and 52L are located on the negative electrode conductor 20N side. Connecting conductor 51H, together with capacitor 41H, forms path R1H connecting the positive electrode conductor 20P and the base conductor 30. Connecting conductor 52H, together with capacitor 42H, forms path R2H connecting the positive electrode conductor 20P and the base conductor 30. Connecting conductor 51L, together with capacitor 41L, forms path R1L connecting the negative electrode conductor 20N and the base conductor 30. The connecting conductor 52L, together with the capacitor 42L, forms a path R2L that connects the negative electrode conductor 20N and the base conductor 30.

[0037] The positive electrode conductor 20P has a connection point P1 to which path R1H is connected, and a connection point P2 to which path R2H is connected. The negative electrode conductor 20N has a connection point N1 to which path R1L is connected, and a connection point N2 to which path R2L is connected. The base conductor 30 has a connection point B1 to which paths R2H and R2L are connected, and a connection point B2 to which paths R1H and R1L are connected. Connection points B1, B2, N1, N2, P1, and P2 are connection points (nodes) between conductors. The base conductor 30 has a connection point B3 to the housing 8, which is a grounding member. Connection point B3 is sometimes referred to as a grounding point or grounding section.

[0038] Note that connection points P1 and N1 correspond to the first power supply connection points, and connection points P2 and N2 correspond to the second power supply connection points. Connection points B1 and B2 correspond to the base connection points. Connection point B1 corresponds to the first base connection point, and connection point B2 corresponds to the second base connection point. Connection point B3 corresponds to the grounding point.

[0039] Details of the capacitor module 6 will be described later. Note that the power converter 4 only needs to include a power converter and a capacitor module 6. The illustrated power converter 4 includes an inverter 5, which is a DC-AC converter, and a capacitor module 6. A smoothing capacitor 7 may be connected to the DC bus between the inverter 5 and the capacitor module 6. The power converter is not limited to the inverter 5. The power converter may be, for example, a DC-DC converter. The power converter 4 may include a DC-DC converter and a capacitor module 6. The power converter 4 may include an inverter 5, a converter, and a capacitor module 6.

[0040] The capacitor module 6 may include a smoothing capacitor 7. In this case, the positive terminal of the smoothing capacitor 7 is connected to the positive conductor 20P, and the negative terminal is connected to the negative conductor 20N. The capacitor module 6 may also include an X capacitor. The power converter 4 may include elements that constitute a filter device together with the capacitor module 6, such as a choke coil. The power converter 4 may also include a snubber circuit.

[0041] The power converter 4 may include a drive circuit for the switching elements that make up the inverter 5, etc. The drive circuit supplies a drive voltage to the gate of the corresponding arm's switching element based on a drive command from the control circuit. The drive circuit drives the corresponding switching element, i.e., turns it on or off, by applying the drive voltage. The drive circuit is sometimes referred to as a driver.

[0042] The power converter 4 may include a control circuit for the switching element. The control circuit generates drive commands for operating the switching element and outputs them to the drive circuit. The control circuit generates drive commands based on, for example, torque requests input from a higher-level ECU (not shown) and signals detected by various sensors. ECU is an abbreviation for Electronic Control Unit.

[0043] As various sensors, for example, there are a current sensor, a rotation angle sensor, and a voltage sensor. The current sensor detects the phase current flowing through each phase winding 3a. The rotation angle sensor detects the rotation angle of the rotor of the motor generator 3. The voltage sensor detects the voltage across the smoothing capacitor 7. The control circuit outputs, for example, a PWM signal as a drive command. The control circuit is configured to include, for example, a processor and a memory. PWM is an abbreviation for Pulse Width Modulation.

[0044] <High-frequency noise> Figure 2 is a diagram for explaining the propagation path of common-mode noise. In Figure 2, the common-mode noise is indicated by a solid arrow.

[0045] A parasitic capacitance 16 exists between the inverter 5 (switching element 13) and a metal member such as the housing 8. A parasitic capacitance 17 exists between the winding 3a of the motor generator 3 and a metal member such as the motor housing. The parasitic capacitances 16 and 17 are sometimes referred to as stray capacitances. The common-mode noise generated with the operation of the switching element 13 flows, for example, from the inverter 5 to the body ground (GND) through the parasitic capacitance 16 and the housing 8. The common-mode noise flows, for example, from the winding 3a to the body ground through the parasitic capacitance 17.

[0046] The power conversion device 4 includes a capacitor module 6 including a Y capacitor 40. The Y capacitor 40 has a low impedance in the high-frequency range. The path R1H including the capacitor 41H and the path R2H including the capacitor 42H bypass the common-mode noise between the positive conductor 20P (P bus) and the body ground. The path R1L including the capacitor 41L and the path R2L including the capacitor 42L bypass the common-mode noise between the negative conductor 20N (N bus) and the body ground.

[0047] The noise current flows through the path of body ground → connection part B3 of base conductor 30 → connection part B2 → path R1H → connection part P1 of positive conductor 20P → connection part P2 → positive terminal 22P. The noise current flows through the path of body ground → connection part B3 of base conductor 30 → connection part B2 → connection part B1 → path R2H → connection part P2 of positive conductor 20P → positive terminal 22P. The noise current flows through the path of body ground → connection part B3 of base conductor 30 → connection part B2 → path R1L → connection part N1 of positive conductor 20P → connection part N2 → negative terminal 22N. The noise current flows through the path of body ground → connection part B3 of base conductor 30 → connection part B2 → connection part B1 → path R2L → connection part N2 of negative conductor 20N → negative terminal 22N.

[0048] The Y capacitor 40 provides a path for the common-mode noise current to flow from the body ground through the Y capacitor 40 to the DC bus. The Y capacitor 40 bypasses the noise current. Thereby, the common-mode noise can be reduced. The Y capacitor 40 can suppress the flow of the noise current to the DC power supply 2 side. The Y capacitor 40 can reduce the loop of the noise current.

[0049] The Y capacitor 40 is connected in series between the P bus (positive conductor 20P) and the N bus (negative conductor 20N). Therefore, the Y capacitor 40 bypasses the normal-mode noise current. Thereby, the normal-mode noise can also be reduced.

[0050] <Capacitor Module> Figure 3 is a circuit diagram showing a capacitor module. In the exemplary capacitor module 6, the capacitor 41H is mounted on the connecting conductor 51H at a position away from the connection part P1 of the positive conductor 20P. The capacitor 42H is mounted on the connecting conductor 52H at a position away from the connection part P2 of the positive conductor 20P. The capacitor 41L is mounted on the connecting conductor 51L at a position away from the connection part N1 of the negative conductor 20N. The capacitor 42L is mounted on the connecting conductor 52L at a position away from the connection part N2 of the negative conductor 20N. Thereby, the influence of the heat of the power conductor 20 due to energization on the Y capacitor 40 can be reduced.

[0051] The first path, path R1, and the second path, path R2, are connected in a cross-connection between the power conductor 20 and the base conductor 30. In the positive conductor 20P, connection point P2 is located closer to the inverter 5 than connection point P1. In the negative conductor 20N, connection point N2 is located closer to the inverter 5 than connection point N1. In the base conductor 30, connection point B2 is located at a different position from connection point B1 such that an impedance exists between it and connection point B1. In the example base conductor 30, connection point B1 is located further from connection point B3 than connection point B2. The potentials of connection points B1 and B2 are different.

[0052] Route R1H connects the connection point P1 on the DC power supply 2 side of the positive conductor 20P to the connection point B2 on the connection point B3 side of the base conductor 30. Route R2H connects the connection point P2 on the inverter 5 side of the positive conductor 20P to the connection point B1 on the base conductor 30, which is located further away from connection point B3 than from connection point B2. Route R1L connects the connection point N1 on the DC power supply 2 side of the negative conductor 20N to the connection point B2 on the connection point B3 side of the base conductor 30. Route R2L connects the connection point N2 on the inverter 5 side of the negative conductor 20N to the connection point B1 on the base conductor 30, which is located further away from connection point B3 than from connection point B2.

[0053] Figure 3 shows the inductance L and impedance Z. Inductance L1 is the parasitic inductance of the connection section 23P, which is the portion between connection section P1 and connection section P2 in the positive conductor 20P. Impedance Z1 is the impedance of connection section 23P. Inductance L2 is the parasitic inductance of the connection section 31, which is the portion between connection section B1 and connection section B2 in the base conductor 30. Impedance Z2 is the impedance of connection section 31. Inductance L3 is the parasitic inductance of the connection section 23N, which is the portion between connection section N1 and connection section N2 in the negative conductor 20N. Impedance Z3 is the impedance of connection section 23N.

[0054] Inductance L4 is the inductance between connections P1 and B2 in path R1H. Impedance Z4 is the impedance between connections P1 and B2. Inductance L5 is the inductance between connections P2 and B1 in path R2H. Impedance Z5 is the impedance between connections P2 and B1. Inductance L6 is the parasitic inductance between connections N1 and B2 in path R1L. Impedance Z6 is the impedance between connections N1 and B2. Inductance L7 is the parasitic inductance between connections N2 and B1 in path R2L. Impedance Z7 is the impedance between connections N2 and B1.

[0055] The inductances L4, L5, L6, and L7 include at least the parasitic inductance of the connecting conductor 50 in the corresponding paths R1 and R2. In addition to the parasitic inductance of the connecting conductor 50, the inductances L4, L5, L6, and L7 may also include the equivalent series inductance (ESL) of the mounted Y capacitor 40. The impedances Z4, Z5, Z6, and Z7 include at least the impedance of the connecting conductor 50 in the corresponding paths R1 and R2. In addition to the impedance of the connecting conductor 50, the impedances Z4, Z5, Z6, and Z7 may also include the impedance of the mounted Y capacitor 40.

[0056] The inductance L8 is the parasitic inductance of the connection section 32, which is the portion between connection section B2 and connection section B3 in the base conductor 30. The impedance Z8 is the impedance of the connection section 23. In the example capacitor module 6, the impedance Z8 is smaller than any of the impedances Z4, Z5, Z6, and Z7. The inductance L8 is smaller than any of the inductances L4, L5, L6, and L7. In the high-frequency region, the value obtained by multiplying the inductance by the frequency corresponds to the impedance. The frequency is the frequency of the current flowing through the conductor.

[0057] In the capacitor module 6, as described above, paths R1 and R2 are connected in a diagonal configuration between the power conductor 20 and the base conductor 30. This forms a Wheatstone bridge circuit in the capacitor module 6. The Wheatstone bridge circuit is sometimes referred to as a Wheatstone bridge circuit. Figure 4 shows an example of a Wheatstone bridge circuit provided in the capacitor module. Figure 4 shows the Wheatstone bridge circuit formed between the positive electrode conductor 20P and the base conductor 30. Connections P2 and B2 are located diagonally opposite each other, and connections P1 and B1 are located diagonally opposite each other. Connections P2 and B2 are located on the high-frequency source side.

[0058] In the example Wheatstone bridge circuit, when the product of impedance Z1 and impedance Z2 is equal to the product of impedance Z4 and impedance Z5, the potential difference (voltage) between connection point P1 and connection point B1 becomes zero. No current flows between connection point P1 and connection point B1, and the impedance Z0 between connection point P1 and connection point B1 becomes zero. Since the potential difference between connection point P1 and connection point B1 is zero, the potential difference between the positive conductor 20P and the base conductor 30 is approximately zero. Therefore, impedance Z4 can be made approximately zero. Also, impedance Z5 can be made approximately zero. In other words, impedances Z4 and Z5 can be canceled out. Inductances L4 and L5 can be canceled out.

[0059] Even if the product of impedance Z1 and impedance Z2 differs by about 50% from the product of impedance Z4 and impedance Z5, impedances Z4 and Z5 can still be reduced to some extent. Therefore, it is preferable to balance the impedances so that the difference between the product of impedance Z1 and impedance Z2 and the product of impedance Z4 and impedance Z5 is 50% or less. More preferably, the impedances should be balanced so that the product of impedance Z1 and impedance Z2 and the product of impedance Z4 and impedance Z5 are approximately the same. Approximately the same means that a manufacturing tolerance, for example, a few percent deviation, can be tolerated. Even more preferably, the impedances should be balanced so that the product of impedance Z1 and impedance Z2 and the product of impedance Z4 and impedance Z5 are perfectly the same.

[0060] Although not shown in the diagram, in the capacitor module 6, a Wheatstone bridge circuit is also formed between the negative conductor 20N and the base conductor 30, with connection points N2 and B2 positioned on the high-frequency source side. When the product of impedance Z3 and impedance Z2 is equal to the product of impedance Z3 and impedance Z7, the potential difference between connection point N1 and connection point B1 becomes zero. By balancing the impedances as described above, impedances Z6 and Z7 can be canceled out to a considerable extent.

[0061] Figure 5 shows an example of the structure of a capacitor module. Figure 5 shows an example of the arrangement of conductors and Y capacitors to balance impedance in a Wheatstone bridge circuit. In Figure 5, each conductor is shown as an example of a busbar. Figure 5 illustrates the current path of common-mode noise flowing on the positive conductor side.

[0062] In the example capacitor module 6, the positive conductor 20P and negative conductor 20N constituting the DC bus extend in the X direction. The positive conductor 20P and the negative conductor 20N run parallel to each other in the Y direction with a predetermined distance between them. The X direction and the Y direction are orthogonal to each other. The positive conductor 20P and the negative conductor 20N face each other in the Y direction. The connecting conductors 50 constituting branch lines branching off from the DC bus extend in the Y direction. The multiple connecting conductors 50 extend toward the same side of the power supply conductor 20 in the Y direction.

[0063] The connecting conductor 51H extends in the Y direction from the connection part P1 on the positive terminal 21P side. The connecting conductor 51L extends in the Y direction from the connection part N1 on the negative terminal 21N side. The connecting conductor 52H extends in the Y direction from the connection part P2 on the positive terminal 22P side. The connecting conductor 52L extends in the Y direction from the connection part N2 on the negative terminal 22N side. The connecting conductors 51H and 51L run parallel to each other with a predetermined distance between them in the X direction. The connecting conductors 51H and 51L face each other in the X direction. The connecting conductors 52H and 52L run parallel to each other with a predetermined distance between them in the X direction. The connecting conductors 52H and 52L face each other in the X direction.

[0064] The base conductor 30 extends in the Y direction. The base conductor 30 is positioned between the opposing portions of the connecting conductors 51H and 51L and the opposing portions of the connecting conductors 52H and 52L. The base conductor 30 is positioned between the connecting conductors 51H and 52H in the X direction. The base conductor 30 is positioned between the connecting conductors 52H and 52L in the X direction. The connection portion B3 of the base conductor 30 is located closer to the power conductor 20 in the Y direction than the connection portions B1 and B2. The connection portion B3 is located between the power conductor 20 and the connection portions B1 and B2. The connection portion B2 is located closer to the power conductor 20 in the Y direction than the connection portion B1. The connection portion B1 is located further from the power conductor 20 in the Y direction than the connection portions B1 and B3. Of the connection portions B1 and B2, connection portion B2 is connected to connection portion B3, which is the ground portion. In the example base conductor 30, a connection portion B3 is provided near one of the ends, and a connection portion B1 is provided near the other end.

[0065] With the above arrangement, the inductances L1, L2, L3, L4, L5, L6, L7, and L8 can be easily adjusted by adjusting, for example, the length, width, and thickness of the power supply conductor 20 and the connecting conductor 50, and the connection position (mounting position) of the Y capacitor 40. In other words, the impedances Z1, Z2, Z3, Z4, Z5, Z6, Z7, and Z8 can be easily adjusted. Note that the arrangement shown in Figure 5 is merely an example. For example, the lengths of the positive conductor 20P and the negative conductor 20N may be made different. The position of the end of the connecting conductor 50 that is away from the power supply conductor 20 may also be made different.

[0066] Figure 6 shows an example of a base conductor fixing structure. Figure 7 shows another example of a base conductor fixing structure. Figure 8 shows another example of a base conductor fixing structure. Figure 9 shows another example of a base conductor fixing structure. Figure 10 shows another example of a base conductor fixing structure. Figures 6 to 10 show several examples of fixing structures for the base conductor 30 that the capacitor module 6 can adopt.

[0067] In Figure 6, the base conductor 30 is fixed to the housing 8. Specifically, the base conductor 30 is fixed to the housing 8 by fastening members 60 such as bolts. The fastening member 60 has a head and a column portion connected to the head. The fastening member 60 fixes the base conductor 30 to the housing 8 by the column portion being inserted through the through hole in the base conductor 30 and screwed into the housing 8, and the head clamping the base conductor 30 between itself and the housing 8. Of the base conductor 30, the portion around the through hole, that is, the portion clamped by the head, is grounded to the housing 8 and forms the connection portion B3.

[0068] In Figure 6, a portion of the base conductor 30 is floating relative to the housing 8. There is space directly beneath the floating portion of the base conductor 30. In the base conductor 30 of Figure 6, a portion of the connection section 32 is bent relative to the portion including connection section B3 and extends in the Z direction. The Z direction is perpendicular to both the X and Y directions described above. Connection sections B1, B2 and the connection section 31 are bent relative to the portion of the connection section 32 extending in the Z direction and extend in the Y direction at a position away from the housing 8. Since connection section B1 and the connection section 31 are not in contact with the housing 8, it is easy to adjust the inductance L2 and, consequently, the impedance Z2. For example, it is easy to increase the inductance L2 and, consequently, the impedance Z2.

[0069] In Figure 7, a low-conductivity member 61 is positioned between the portion of the base conductor 30 that is floating relative to the housing 8 and the housing 8. The low-conductivity member 61 is a material with lower conductivity (electrical conductivity) than the base conductor 30. The low-conductivity member 61 is a material with lower conductivity than the housing 8, which is a grounding member. The low-conductivity member 61 may be composed of an electrically insulating material such as resin. The low-conductivity member 61 may be composed of a metallic material with lower conductivity than the base conductor 30. In a plan view in the Z direction, the low-conductivity member 61 is positioned to overlap almost the entire area of ​​the floating portion of the base conductor 30. The connection portion B1 and the connection portion 31 are positioned on the housing 8 via the low-conductivity member 61. The low-conductivity member 61 supports the base conductor 30 at a predetermined position away from the housing 8.

[0070] In Figure 8, the low-conductivity member 61 is positioned to overlap with a portion of the floating part of the base conductor 30. The low-conductivity member 61 supports the base conductor 30 at a predetermined position away from the housing 8. In the example, the low-conductivity member 61 supports the base conductor 30 near the end on the connection portion B1 side. The low-conductivity member 61 supports only a portion of the connection portion 31.

[0071] In Figure 9, a connection portion B2 is provided in the base conductor 30 in the portion extending in the Y direction on the housing 8. The connection portion 31 includes a portion extending in the Z direction and a portion extending in the Y direction at a position away from the housing 8. The connection portion 32 is located on the housing 8. Because the connection portion 32 is in contact with the housing 8, the inductance L8 and, consequently, the impedance Z8 can be reduced. In Figure 9, there is a space directly below the floating portion of the base conductor 30, but a low-conductivity member 61 may be placed there, as shown in Figures 7 and 8.

[0072] In Figure 10, an inductor component 33 is inserted in the middle of the base conductor 30. The inductor component 33 is mounted on the base conductor 30 between connection points 31. By mounting the inductor component 33, the degree of freedom in setting the inductance L2, and consequently the impedance Z2, between connection points 31 can be increased. For example, the inductance L2 can be increased, and consequently the impedance Z2 can be increased. In Figure 10, a low-conductivity member 61 is located directly below the floating portion of the base conductor 30, but a configuration with a space, as shown in Figure 6, is also possible.

[0073] <Summary of the First Embodiment> The capacitor module 6 of this embodiment comprises a positive electrode conductor 20P and a negative electrode conductor 20N which are power supply conductors 20, a base conductor 30 connected to a grounding member, a Y capacitor 40, a connecting conductor 51 which constitutes path R1, and a connecting conductor 52 which constitutes path R2. The Y capacitor 40 includes capacitors 41 and 42 connected in parallel between at least one of the power supply conductors 20 and the base conductor 30. Path R1 is composed of a connecting conductor 51 and a capacitor 41 mounted on the connecting conductor 51 at a position away from the connection point with the power supply conductor 20. Path R2 is composed of a connecting conductor 52 and a capacitor 42 mounted on the connecting conductor 52 at a position away from the connection point with the power supply conductor 20. Paths R1 and R2 are connected in a diagonal configuration between the power supply conductor 20 and the base conductor 30.

[0074] The power conductor 20 has connection points P1 and N1 to which path R1 is connected, and connection points P2 and N2 which are located closer to the inverter 5, which is a power converter, than connection points P1 and N1, and to which path R2 is connected. The base conductor 30 has a connection point B1 to which path R2 is connected, and a connection point B2 which is located away from connection point B1 and to which path R1 is connected, such that an impedance Z2 exists between connection point B1 and B1.

[0075] As described above, the capacitors 41 and 42, which constitute the Y capacitor 40, are positioned away from the power supply conductor 20 in the corresponding connecting conductors 51 and 52. By keeping the Y capacitor 40 away from the power supply conductor 20, which forms the DC bus, the effect of the heat generated by the power supply conductor 20 due to current flow on the Y capacitor 40 can be reduced.

[0076] On the other hand, if capacitors 41 and 42 are placed at a distance from the power supply conductor 20, the connecting conductors 51 and 52 become longer, increasing the parasitic inductance and, consequently, the impedance. When the impedance increases, the effect of the Y capacitor 40 in bypassing high-frequency noise decreases.

[0077] In this embodiment, the cross-connection allows the impedance Z2 between connection points B1 and B2 to form a Wheatstone bridge circuit together with, for example, the impedance Z1 between connection points P1 and P2, the impedance Z4 of path R1H (R1), and the impedance Z5 of path R2H (R2). Therefore, by adjusting each impedance Z1, Z2, Z4, and Z5, the impedances Z4 and Z5 can be reduced, ideally to zero. Even when the Y capacitor 40 is placed at a distance from the power supply conductor 20, the effect of the Y capacitor 40 can be improved by impedance cancellation. A power conversion device 4 equipped with a capacitor module 6 can also achieve the above-described effects.

[0078] As illustrated, the impedance Z8 between connection B2 and ground connection B3 in the base conductor 30 may be made smaller than, for example, the impedances Z4 and Z6 of path R1. The impedance Z8 may also be made smaller than the impedances Z5 and Z7 of path R2. The connection section 32, which is the portion between connection B2 and B3, forms part of the noise current path. By making the impedance Z8 smaller, the impedance of the entire bypass including the Y capacitor 40 is reduced. Therefore, the common-mode noise reduction effect of the Y capacitor 40 can be improved.

[0079] As illustrated, connection point B1 may be positioned further away from connection point B3 than connection point B2. This makes it easier to increase the inductance L2 of the connection point 31, which is the portion between connection points B1 and B2. In other words, it makes it easier to increase the impedance Z2. This makes it easier to balance the impedances in the Wheatstone bridge circuit. In other words, it makes it easier to cancel out the impedances Z4, Z5, Z6, and Z7 of the paths R1 and R2.

[0080] As illustrated, it is preferable to make the connection B1 and the space between the connection points 31 in the base conductor 30 non-contact with the housing 8, which is the grounding member. This makes it easier to increase the inductance L2 between the connection points 31. In other words, it makes it easier to increase the impedance Z2. This makes it easier to balance the impedances in the Wheatstone bridge circuit. In other words, it makes it easier to cancel out the impedances Z4, Z5, Z6, Z7 of the paths R1 and R2.

[0081] As illustrated, the connection portion B1 and the space between the connection portions 31 may be arranged on the housing 8 via a low-conductivity member 61. This allows the base conductor 30 to be stably positioned on the housing 8 while achieving the above-mentioned effects.

[0082] As illustrated, an inductor component 33 may be mounted between the connection points B1 and B2 in the base conductor 30. The inductor component 33 makes it easier to adjust the inductance L2 and, consequently, the impedance Z2. This makes it easier to balance the impedance in the Wheatstone bridge circuit. In other words, it makes it easier to cancel out the impedances Z4, Z5, Z6, and Z7 of the paths R1 and R2.

[0083] As illustrated, in a configuration where the power conductor 20 extends in a predetermined direction X, the base conductor 30 may be placed between the connecting conductors 51 and 52 in the X direction. This makes it easier to cross-connect the path R1 including the connecting conductor 51 and capacitor 41, and the path R2 including the connecting conductor 52 and capacitor 42. In other words, it makes it easier to form a Wheatstone bridge circuit. The size of the capacitor module 6 that forms the Wheatstone bridge circuit can be reduced.

[0084] As illustrated, the connecting conductors 51 and 52 may be configured to extend in a direction different from the X direction from the power supply conductor 20. For example, the connecting conductors 51 and 52 may be configured to extend in the Y direction. This configuration reduces the influence of the heat of the power supply conductor 20 on the Y capacitor 40 compared to the configuration in which they extend along the power supply conductor 20.

[0085] As illustrated, the connecting conductors 51 and 52 may be configured to extend toward the same side relative to the power supply conductor 20. This allows for a reduction in the size of the capacitor module 6 in the Y direction.

[0086] As illustrated, the grounding connection B3 may be positioned closer to the power conductor 20 than the connection parts B1 and B2. This makes it easier to cross-connect the paths R1 and R2 compared to a configuration where the connection B3 is positioned further away from the power conductor 20 than the connection parts B1 and B2. In other words, it makes it easier to form a Wheatstone bridge circuit. The size of the capacitor module 6 can be reduced.

[0087] <Modification> The structure of the capacitor module is not limited to the example shown in Figure 5. For example, as shown in Figure 11, the connection part B1 may be provided at a position away from the end in the extending direction (Y direction) of the base conductor 30. The base conductor 30 extends beyond the connection part B1. The other configurations are the same as in Figure 5. Note that in Figure 11, the lengths of the connecting conductors 51H and 51L may be made shorter than the lengths of the connecting conductors 52H and 52L so that the capacitors 41H and 41L are connected near the ends of the connecting conductors 51H and 51L.

[0088] As shown in Figure 12, connection part B3 may be provided such that the power conductor 20 is located between connection part B3 and connection parts B1 and B2. The base conductor 30 crosses the power conductor 20. Connection part B3 is located on the opposite side of the power conductor 20 from connection parts B1 and B2. Connection part B3 is located closer to the power conductor 20 than connection parts B1 and B2. The other configurations are the same as in Figure 5. This configuration improves the flexibility of the wiring. Connection part B3 can be secured even when it is difficult to provide connection part B3 on the connecting conductor 50 side.

[0089] As shown in Figure 13, the connecting conductors 51 and 52 may be configured to extend to opposite sides of the power supply conductor 20. The base conductor 30 is located between the connecting conductors 51 and 52 in the X direction. The base conductor 30 crosses the power supply conductor 20. The power supply conductor 20 is located between the connection parts B1 and B2 in the Y direction. Connection part B1 is located on the opposite side of the power supply conductor 20 from connection part B2. Connection part B3 is provided on the connection part B2 side of the power supply conductor 20. The capacitor 42 and connecting conductor 52 are located on the opposite side of the power supply conductor 20 from the capacitor 41 and connecting conductor 51. With this configuration, it is easier to increase the inductance L2. The configuration shown in Figure 5 makes it easier to reduce the size. Note that connection part B3 may be provided at the end of connection part B2 instead of between connection parts B1 and B2.

[0090] As shown in Figure 14, the base conductor 30 may include a portion that extends in the same direction as the power supply conductor 20. The example base conductor 30 has a roughly L-shape in plan. The connection section 31 extends in the X direction, and the connection section 32 extends in the Y direction. A connection section B1 is provided at one end of the connection section 31, and a connection section B2 is provided at the other end. The other configurations are the same as in Figure 5. With this configuration, the distance between the connecting conductor 51 and the connecting conductor 52 becomes longer. That is, the connection sections P1 and P2 are separated. Similarly, the connection sections N1 and N2 are separated. Therefore, the inductances L1 and L3 can be increased, and consequently the impedances Z1 and Z3 can be increased. In addition, the size in the Y direction can be reduced.

[0091] (Second Embodiment) This embodiment is a modification based on the preceding embodiment, and the description of the preceding embodiment can be used by reference. In the preceding embodiment, of the connecting parts B1 and B2, connecting part B2 was connected to connecting part B3. Alternatively, of the connecting parts B1 and B2, connecting part B1 may be connected to connecting part B3.

[0092] Figure 15 is a circuit diagram showing an example of a capacitor module according to this embodiment. Figure 15 corresponds to Figure 3. In Figure 15, connection part B1 is connected to connection part B3. The inductance between connection parts B1 and B3 is L8, and the impedance between connection parts B1 and B3 is Z8. The other configurations are the same as those described in the prior embodiment.

[0093] In this embodiment as well, paths R1 and R2 are connected in a cross-connection between the power conductor 20 and the base conductor 30. As a result, a Wheatstone bridge circuit is formed in the capacitor module 6. In the Wheatstone bridge circuit, when the product of impedance Z1 and impedance Z2 is equal to the product of impedance Z4 and impedance Z5, the potential difference (voltage) between connection point P2 and connection point B2 becomes zero. By balancing the impedances, impedances Z4 and Z5 can be canceled out to a considerable extent. Therefore, the effect of the Y capacitor 40 can be improved while reducing the thermal effect.

[0094] (Third Embodiment) This embodiment is a modification based on the preceding embodiment, and the description of the preceding embodiment can be used by reference. In the preceding embodiment, the base conductor 30 had an impedance Z8 (inductance L8). Alternatively, the base conductor 30 may be configured not to have an impedance Z8 (inductance L8).

[0095] Figure 16 is a circuit diagram showing an example of a capacitor module according to this embodiment. Figure 16 corresponds to Figure 3. In Figure 16, connection part B2 is connected to connection part B3. However, there is no impedance Z8 between connection parts B2 and B3. The impedance Z8 is almost zero. The impedance Z8 is smaller than the impedances Z4 and Z5. There is no inductance L8 between connection parts B2 and B3. The inductance L8 is almost zero. Connection part B2 is provided almost coincidentally with connection part B3. The other configurations are the same as those described in the prior embodiment.

[0096] According to this embodiment, since there is no impedance Z8, that is, impedance Z8 is zero, the impedance of the entire bypass including the Y capacitor 40 is further reduced. Therefore, the common-mode noise reduction effect of the Y capacitor 40 can be further improved.

[0097] Alternatively, the connection part B1 may be connected to the connection part B3, and the configuration may not have an impedance Z8 (inductance L8).

[0098] (Fourth Embodiment) This embodiment is a modification based on the preceding embodiment, and the description of the preceding embodiment can be used by reference. In the preceding embodiment, one of the connection parts B1 and B2 was connected to connection part B3. In other words, it was grounded on one side. Alternatively, each of the connection parts B1 and B2 may be connected to connection part B3. In other words, it may be grounded on both sides of the connection parts B1 and B2.

[0099] Figure 17 is a circuit diagram showing an example of a capacitor module according to this embodiment. Figure 17 corresponds to Figure 3. In Figure 17, connection parts B1 and B2 are connected to connection part B3. Connection part B3 includes connection parts B31 and B32. Connection part B2 is connected to connection part B31. Connection part B1 is connected to connection part B32. Connection parts B31 and B32 are connected to different positions in the housing 8. That is, their grounding positions are different. In Figure 17, there is no impedance between connection parts B2 and B31. There is no impedance between connection parts B1 and B32. The impedance is almost zero. The other configurations are the same as those described in the prior embodiment.

[0100] According to this embodiment, even in a configuration where grounding is performed on both sides of the connection parts B1 and B2, the impedance between the power conductor 20 and the base conductor 30 can be canceled by the cross-connection of path R1 and path R2. Therefore, the effect of the Y capacitor 40 can be improved while reducing the thermal influence.

[0101] Furthermore, a configuration in which impedance exists between connection parts B2 and B31 is also possible. A configuration in which impedance exists between connection parts B1 and B32 is also possible. In the case of a configuration in which grounding is performed on both sides of connection parts B1 and B2, for example, in the fixing structure of the base conductor 30 illustrated in Figures 6 to 10, a fixing structure to the housing 8 (grounding member) similar to that on the connection part B2 side may be provided on the connection part B1 side as well.

[0102] (Fifth Embodiment) This embodiment is a modification based on the preceding embodiment, and the description of the preceding embodiment can be referenced. In the preceding embodiment, paths R1H and R2H were connected in a cross configuration between the positive electrode conductor 20P and the base conductor 30, and paths R1L and R2L were connected in a cross configuration between the negative electrode conductor 20N and the base conductor 30. Alternatively, paths R1 and R2 may be connected in a cross configuration between one of the positive electrode conductors 20P and the negative electrode conductor 20N and the base conductor 30, and paths R1 and R2 may not be connected in a cross configuration between the other positive electrode conductor 20P and the negative electrode conductor 20N and the base conductor 30.

[0103] Figure 18 is a circuit diagram showing an example of a capacitor module according to this embodiment. Figure 18 corresponds to Figure 3. In Figure 18, paths R1 and R2 are connected in a cross configuration between the positive conductor 20P and the base conductor 30. There is no cross configuration between the negative conductor 20N and the base conductor 30. Similar to Figure 16, there is no impedance Z8 between the connection points B2 and B3. The impedance Z8 is almost zero. The other configurations are the same as those described in the prior embodiment.

[0104] In this embodiment, paths R1 and R2 are cross-connected between the positive conductor 20P and the base conductor 30, forming a Wheatstone bridge circuit. Therefore, impedance balance can be achieved, and impedances Z4 and Z5 can be reduced, ideally to zero. Although the effect is halved because the negative conductor 20N side is not cross-connected, the effect of the Y capacitor 40 can be improved by impedance cancellation even when the Y capacitor 40 is placed at a distance from the power supply conductor 20.

[0105] Note that grounding is not limited to the connection part B2 side. As in Figure 15, grounding may be done on the connection part B1 side. As shown in Figure 19, grounding may be done on both sides of connection parts B1 and B2. Impedance may exist between connection part B2 and connection part B3. Impedance may exist between connection part B1 and connection part B3.

[0106] Although not shown in the diagram, the paths R1 and R2 may be connected in a cross configuration between the negative electrode conductor 20N and the base conductor 30, but not between the positive electrode conductor 20P and the base conductor 30.

[0107] (Other Embodiments) The disclosures in this specification and drawings are not limited to the exemplary embodiments. The disclosures include the exemplary embodiments and variations thereof by those skilled in the art. For example, the disclosures are not limited to combinations of parts and / or elements shown in the embodiments. The disclosures are implementable in a variety of combinations. The disclosures may have additional parts that can be added to the embodiments. The disclosures include those in which parts and / or elements of an embodiment have been omitted. The disclosures include substitutions or combinations of parts and / or elements between one embodiment and another. The scope of the disclosed technical areas is not limited to the descriptions of the embodiments. Some of the scope of the disclosed technical areas are indicated by the descriptions of the claims and should be understood to include all modifications within the meaning and scope equivalent to the descriptions of the claims.

[0108] The disclosures in the specification and drawings are not limited by the claims. The disclosures in the specification and drawings encompass the technical ideas described in the claims and extend to a wider and more diverse range of technical ideas than those described in the claims. Therefore, a variety of technical ideas can be extracted from the disclosures in the specification and drawings without being bound by the claims.

[0109] When an element or layer is referred to as “on top of,” “connected to,” “linked to,” or “joined,” it may be directly on top of, connected to, or joined to another element or layer, and there may also be an intervening element or layer. In contrast, when an element is referred to as “directly on top of,” “directly connected to,” “directly linked to,” or “directly joined to” another element or layer, there is no intervening element or layer. Other words used to describe relationships between elements should be interpreted in a similar manner (e.g., “between” vs. “directly between,” “adjacent” vs. “directly adjacent,” etc.). As used in this specification, the term “and / or” includes any combination and all combinations relating to one or more of the enumerated items in question. That is, the statement A and / or B means at least one of A and B.

[0110] Spatially relative terms such as “inside,” “outside,” “back,” “below,” “low,” “above,” and “high” are used here to facilitate descriptions of the relationship between one element or feature and other elements or features, as illustrated. Spatially relative terms may be intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the drawings. For example, if the device in the drawing is turned upside down, an element described as “below” or “directly below” another element or feature will be oriented “above” the other element or feature. Thus, the term “below” can encompass both up and down orientations. The device may also be oriented in other directions (it may be rotated 90 degrees or in other directions), and the spatially relative descriptors used in this specification will be interpreted accordingly.

[0111] (Disclosure of Technical Ideas) This specification discloses several technical ideas as described in the following paragraphs. Some paragraphs may be written in a multiple dependent form, where subsequent paragraphs optionally refer to preceding paragraphs. Furthermore, some paragraphs may be written in a multiple dependent form, where they refer to other multiple dependent forms. These paragraphs written in multiple dependent forms define several technical ideas.

[0112] <Technical Concept 1> A capacitor module connected to a power converter (5) including a switching element, comprising: a positive electrode conductor (20P) connected to the DC positive terminal of the power converter; a negative electrode conductor (20N) connected to the DC negative terminal of the power converter; a base conductor (30) connected to a grounding member that provides a reference potential; a Y capacitor (40) including a first capacitor (41) and a second capacitor (42) connected in parallel between a power supply conductor (20) which is at least one of the positive electrode conductor and the negative electrode conductor, and the base conductor; a first connecting conductor (51) electrically connected to the power supply conductor, with the first capacitor mounted at a position away from the connection point with the power supply conductor, and constituting a first path (R1) together with the first capacitor; a second connecting conductor (52) electrically connected to the power supply conductor, with the second capacitor mounted at a position away from the connection point with the power supply conductor, and constituting a second path (R2) together with the second capacitor; A capacitor module comprising: the first path and the second path are connected in a cross-over manner between the power supply conductor and the base conductor; the power supply conductor has a first power supply connection part (P1, N1) to which the first path is connected, and a second power supply connection part (P2, N2) located closer to the power converter than the first power supply connection part and to which the second path is connected; and the base conductor has a base connection part, a first base connection part (B1) to which the second path is connected, and a second base connection part (B2) located away from the first base connection part and to which the first path is connected, such that an impedance exists between the first base connection part and the first base connection part.

[0113] <Technical Concept 2> The capacitor module according to Technical Concept 1, wherein at least one of the base connection portions is connected to a ground portion (B3) which is a connection portion of the base conductor to the grounding member, and the impedance between the ground portion and the base connection portion connected to the ground portion is smaller than the impedances of the first path and the second path, respectively.

[0114] <Technical Concept 3> The capacitor module according to Technical Concept 2, wherein one of the base connection parts is connected to the grounding part, and the other base connection part is located further from the grounding part than the base connection part connected to the grounding part.

[0115] <Technical Concept 4> The capacitor module according to any one of Technical Concepts 1 to 3, wherein the portion of the base conductor between the first base connection portion and the second base connection portion is not in contact with the grounding member.

[0116] <Technical Concept 5> The capacitor module according to technical concept 4, wherein the portion between the first base connection portion and the second base connection portion is arranged on the grounding member via a low-conductivity member (61) having lower conductivity than the base conductor.

[0117] <Technical Concept 6> A capacitor module according to any one of Technical Concepts 1 to 5, wherein an inductor component (33) is mounted between the first base connection portion and the second base connection portion in the base conductor.

[0118] <Technical Concept 7> A capacitor module according to any one of Technical Concepts 1 to 6, wherein the power supply conductor extends in a predetermined direction, and the base conductor is located between the first connecting conductor and the second connecting conductor in the predetermined direction.

[0119] <Technical Concept 8> The capacitor module according to Technical Concept 7, wherein the first connecting conductor and the second connecting conductor extend from the power supply conductor in a direction different from the predetermined direction.

[0120] <Technical Concept 9> The capacitor module according to technical concept 8, wherein the first connecting conductor and the second connecting conductor extend toward the same side relative to the power supply conductor.

[0121] <Technical Concept 10> A capacitor module according to any one of Technical Concepts 7 to 9, wherein the connection portion of the base conductor with the grounding member is located closer to the power supply conductor than the first base connection portion and the second base connection portion.

[0122] <Technical Concept 11> The capacitor module according to technical concept 7, wherein the base conductor includes a portion extending in the predetermined direction.

[0123] <Technical Concept 12> A power conversion device comprising: a power converter (5) including a switching element; and a capacitor module (6) connected to the power converter, wherein the capacitor module comprises: a positive electrode conductor (20P) connected to the DC positive electrode terminal of the power converter; a negative electrode conductor (20N) connected to the DC negative electrode terminal of the power converter; a base conductor (30) connected to a grounding member that provides a reference potential; a Y capacitor (40) including a first capacitor (41) and a second capacitor (42) connected in series between the positive electrode conductor and the negative electrode conductor, and connected in parallel between a power supply conductor (20) which is at least one of the positive electrode conductor and the negative electrode conductor and the base conductor; and a first connecting conductor (51) electrically connected to the power supply conductor, with the first capacitor mounted at a position away from the connection point with the power supply conductor, and constituting a first path (R1) together with the first capacitor. A power converter comprising: a second connecting conductor (52) electrically connected to the power conductor, the second capacitor mounted at a position away from the connection point with the power conductor, and together with the second capacitor constituting a second path (R2); the first path and the second path are connected in a diagonal manner between the power conductor and the base conductor; the power conductor has a first power connection section (P1, N1) to which the first path is connected, and a second power connection section (P2, N2) provided at a position closer to the power converter than the first power connection section and to which the second path is connected; and the base conductor has a first base connection section (B1) to which the second path is connected, and a second base connection section (B2) to which the first path is connected at a position away from the first base connection section such that an impedance exists between the first base connection section and the second base connection section.

Claims

A capacitor module connected to a power converter (5) including a switching element, A positive electrode conductor (20P) connected to the DC positive terminal of the power converter, The negative electrode conductor (20N) connected to the DC negative terminal of the power converter, A base conductor (30) connected to a grounding member that provides a reference potential, A Y capacitor (40) is connected in series between the positive conductor and the negative conductor, and includes a first capacitor (41) and a second capacitor (42) connected in parallel between the power supply conductor (20), which is at least one of the positive conductor and the negative conductor, and the base conductor, The first connecting conductor (51) is electrically connected to the power supply conductor, and the first capacitor is mounted at a position away from the connection point with the power supply conductor, and together with the first capacitor, constitutes a first path (R1), A second connecting conductor (52) is electrically connected to the power supply conductor, and the second capacitor is mounted at a position away from the connection point with the power supply conductor, and together with the second capacitor, the second connecting conductor (52) constitutes a second path (R2), Equipped with, The first path and the second path are connected in a cross-over configuration between the power conductor and the base conductor. The power conductor has a first power connection section (P1, N1) to which the first path is connected, and a second power connection section (P2, N2) located closer to the power converter than the first power connection section and to which the second path is connected. The capacitor module comprises a base conductor having a first base connection (B1) to which the second path is connected, and a second base connection (B2) to which the first path is connected at a position away from the first base connection, such that an impedance exists between the first base connection and the second base connection. 　 At least one of the base connection portions is connected to a grounding portion (B3) which is a connection portion of the base conductor to the grounding member, The capacitor module according to claim 1, wherein the impedance between the grounding portion and the base connection portion connected to the grounding portion is smaller than the impedances of the first path and the second path, respectively. 　 One of the base connection parts is connected to the grounding part, The capacitor module according to claim 2, wherein the other base connection portion is located further away from the ground portion than the base connection portion connected to the ground portion. 　 The capacitor module according to claim 2 or 3, wherein the portion of the base conductor between the first base connection portion and the second base connection portion is not in contact with the grounding member. 　 The capacitor module according to claim 4, wherein the portion between the first base connection portion and the second base connection portion is arranged on the grounding member via a low-conductivity member (61) having lower conductivity than the base conductor. 　 The capacitor module according to claim 2 or 3, wherein an inductor component (33) is mounted between the first base connection portion and the second base connection portion in the base conductor. 　 The power conductor extends in a predetermined direction, The capacitor module according to claim 1, wherein the base conductor is located between the first connecting conductor and the second connecting conductor in the predetermined direction. 　 The capacitor module according to claim 7, wherein the first connecting conductor and the second connecting conductor extend from the power supply conductor in a direction different from the predetermined direction. 　 The capacitor module according to claim 8, wherein the first connecting conductor and the second connecting conductor extend toward the same side relative to the power supply conductor. 　 The capacitor module according to claim 8 or 9, wherein the connection portion of the base conductor with the grounding member is located closer to the power conductor than the first base connection portion and the second base connection portion. 　 The capacitor module according to claim 7, wherein the base conductor includes a portion extending in the predetermined direction. 　 A power converter (5) including a switching element, A capacitor module (6) connected to the power converter, A power conversion device comprising, The aforementioned capacitor module is A positive electrode conductor (20P) connected to the DC positive terminal of the power converter, The negative electrode conductor (20N) connected to the DC negative terminal of the power converter, A base conductor (30) connected to a grounding member that provides a reference potential, A Y capacitor (40) is connected in series between the positive conductor and the negative conductor, and includes a first capacitor (41) and a second capacitor (42) connected in parallel between the power supply conductor (20), which is at least one of the positive conductor and the negative conductor, and the base conductor, The first connecting conductor (51) is electrically connected to the power supply conductor, and the first capacitor is mounted at a position away from the connection point with the power supply conductor, and together with the first capacitor, constitutes a first path (R1), A second connecting conductor (52) is electrically connected to the power supply conductor, and the second capacitor is mounted at a position away from the connection point with the power supply conductor, and together with the second capacitor, the second connecting conductor (52) constitutes a second path (R2), Equipped with, The first path and the second path are connected in a cross-over configuration between the power conductor and the base conductor. The power conductor has a first power connection section (P1, N1) to which the first path is connected, and a second power connection section (P2, N2) located closer to the power converter than the first power connection section and to which the second path is connected. The power converter has a base conductor having a base connection portion, which includes a first base connection portion (B1) to which the second path is connected, and a second base connection portion (B2) to which the first path is connected at a position away from the first base connection portion such that an impedance exists between the first base connection portion and the second base connection portion.

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