Noise filter and power conversion device

Abstract

A noise filter (30) comprises a first P busbar (41P), a first N busbar (41N), a second P busbar (42P), a second N busbar (42N), a third P busbar (43P), a third N busbar (43N), a P-side capacitor (60P), an N-side capacitor (60N), a P-side ground busbar, and an N-side ground busbar. The second P busbar (42P) branches and extends from the first P busbar (41P), and the second N busbar (42N) branches and extends from the first N busbar (41N), and the second P busbar and the second N busbar are disposed side by side. The third P busbar (43P) extends from the second P busbar (42P) to the opposite side from the second N busbar (42N). The third N busbar (43N) extends from the second N busbar (42N) to the opposite side from the second P busbar (42P). The P-side capacitor (60P) is connected to the third P busbar (43P) and the P-side ground busbar, and the N-side capacitor (60N) is connected to the third N busbar (43N) and the N-side ground busbar. The P-side ground busbar and the N-side ground busbar are connected to different positions of a ground member.

Description

Noise filter and power conversion device Cross-reference to related applications

[0001] This application is based on Japanese Patent Application No. 2025-068374 filed on April 17, 2025, and the entire content of the base application is incorporated herein by reference.

[0002] The disclosure in the present specification relates to a noise filter and a power conversion device.

[0003] Patent Document 1 discloses a power conversion device that can prevent overheating of a zero-phase core for electromagnetic noise control provided in the power conversion device, and can prevent damage to the core and the device.

[0004] Japanese Unexamined Patent Application Publication No. 2017-169414

[0005] Although Patent Document 1 discloses a circuit diagram of a power conversion device including a zero-phase core and a noise filter, it does not mention the structure of the noise filter such as how to assemble the components.

[0006] One object of the present disclosure is to provide a noise filter and a power conversion device capable of suppressing the influence of heat.

[0007] A noise filter according to one aspect of the disclosure includes: a first P bus bar that is an input line on a high potential side; a first N bus bar that is an input line on a low potential side; a second P bus bar that branches from the first P bus bar and is arranged to extend along a predetermined direction; a second N bus bar that branches from the first N bus bar and is arranged side by side with the second P bus bar so as to extend along the predetermined direction; a third P bus bar connected to the second P bus bar and arranged to extend on a side opposite to the second N bus bar with respect to the second P bus bar; a third N bus bar connected to the second N bus bar and arranged to extend on a side opposite to the second P bus bar with respect to the second N bus bar; a P-side capacitor having one end connected to the third P bus bar to remove electromagnetic noise; an N-side capacitor having one end connected to the third N bus bar to remove electromagnetic noise; a P-side ground bus bar that connects the other end of the P-side capacitor to a ground member that provides a ground potential; and an N-side ground bus bar that connects the other end of the N-side capacitor to the ground member, wherein the P-side ground bus bar and the N-side ground bus bar are connected to different positions on the ground member.

[0008] One aspect of the disclosure is a power converter comprising an inverter that converts power by switching operation and a noise filter, wherein the noise filter comprises a first P busbar which is a high-potential input line, a first N busbar which is a low-potential input line, a second P busbar which branches off from the first P busbar and is arranged to extend along a predetermined direction, a second N busbar which branches off from the first N busbar and is arranged alongside the second P busbar and extends along a predetermined direction, and a second N busbar which is connected to the second P busbar and extends on the opposite side of the second N busbar from the second P busbar. The system includes a third P busbar arranged as shown, a third N busbar connected to a second N busbar and arranged to extend on the opposite side of the second P busbar from the second N busbar, a P-side capacitor with one end connected to the third P busbar to remove electromagnetic noise, an N-side capacitor with one end connected to the third N busbar to remove electromagnetic noise, a P-side ground busbar that connects the other end of the P-side capacitor to a grounding member that provides ground potential, and an N-side ground busbar that connects the other end of the N-side capacitor to a grounding member, wherein the P-side ground busbar and the N-side ground busbar are connected to different positions on the grounding member.

[0009] According to the disclosed noise filter and power converter, the magnetic fluxes generated by the currents flowing through the second P busbar and the second N busbar cancel each other out, thereby reducing inductance. Furthermore, compared to the case where the P-side capacitor and the N-side capacitor are connected to the same busbar and grounded at the same location, the amount of current flowing through the busbar connected to the grounding member can be reduced, thereby suppressing the amount of heat generated in that busbar. In addition, by adjusting the lengths of the third P busbar and the third N busbar, heat can be dissipated evenly on both the P-side and N-side.

[0010] The reference numbers in parentheses above are merely examples of correspondences with specific configurations in the embodiments described later, and do not limit the technical scope in any way.

[0011] This figure shows a power conversion circuit and a drive system. This is a perspective view showing a noise filter according to the first embodiment. This is a perspective view showing a noise filter according to the first embodiment. This is a schematic plan view showing a noise filter according to the first embodiment. This is a cross-sectional view along the line V-V in Figure 2.

[0012] 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.

[0013] The noise filter of this embodiment is applied, for example, to a power conversion device for a mobile body that uses a rotating electric machine as its drive source. Examples of mobile bodies include electric vehicles (BEVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), flying vehicles such as electric vertical take-off and landing aircraft and drones, ships, construction machinery, and agricultural machinery. An example of its application to a vehicle will be described below.

[0014] (First Embodiment) First, the general configuration of the vehicle's drive system will be described based on Figure 1.

[0015] <Vehicle Drive System> As shown in Figure 1, the vehicle drive system 1 includes a DC power supply 2, a motor generator 3, and a power conversion circuit 4.

[0016] The DC power supply 2 is a DC voltage source composed of 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 conversion circuit 4 performs power conversion between the DC power supply 2 and the motor generator 3.

[0017] <Power Conversion Circuit> Figure 1 shows an example of a power conversion circuit 4. The illustrated power conversion circuit 4 includes a smoothing capacitor 5, an inverter 6, and a filter circuit 17.

[0018] The smoothing capacitor 5 primarily smooths the DC voltage supplied from the DC power supply 2. The smoothing capacitor 5 is connected to the high-potential input line, P line 7, and the low-potential input line, N line 8. P line 7 is connected to the positive terminal of the DC power supply 2, and N line 8 is connected to the negative terminal of the DC power supply 2. The positive terminal of the smoothing capacitor 5 is connected to P line 7 between the DC power supply 2 and the inverter 6. The negative terminal of the smoothing capacitor 5 is connected to N line 8 between the DC power supply 2 and the inverter 6. The smoothing capacitor 5 is connected in parallel to the DC power supply 2.

[0019] The inverter 6 is a DC-AC conversion circuit. The inverter 6 converts a DC voltage to a three-phase AC voltage according to switching control by a control circuit (not shown) 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 6 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 switching control by the control circuit and outputs it to the P line 7. In this way, the inverter 6 performs bidirectional power conversion between the DC power supply 2 and the motor generator 3.

[0020] The inverter 6 is configured with three phase upper and lower arm circuits 9. The upper and lower arm circuits 9 are sometimes referred to as legs. The upper and lower arm circuits 9 each have an upper arm 9H and a lower arm 9L. The upper arm 9H and lower arm 9L are connected in series between the P line 7 and the N line 8, with the upper arm 9H on the P line 7 side. Hereafter, the upper arm 9H and lower arm 9L may be simply referred to as arms 9H and 9L.

[0021] The connection point between the upper arm 9H and the lower arm 9L is connected to the corresponding phase winding 3a in the motor generator 3 via the output line 10. Of the upper and lower arm circuits 9, the U-phase upper and lower arm circuit 9U is connected to the U-phase winding 3a via the corresponding output line 10. The V-phase upper and lower arm circuit 9V is connected to the V-phase winding 3a via the corresponding output line 10. The W-phase upper and lower arm circuit 9W is connected to the W-phase winding 3a via the corresponding output line 10. At least a portion of each of the P line 7, N line 8, and output line 10 is made of a conductive member such as a busbar.

[0022] The number of switching elements constituting each arm 9H, 9L is not particularly limited. There may be one or more. In the example upper arm 9H, three switching elements are connected in parallel. In the lower arm 9L, three switching elements are connected in parallel. In other words, each of the six arms 9H, 9L of the three-phase upper and lower arm circuit 9 is composed of three switching elements connected in parallel to each other.

[0023] The example switching element is an n-channel type MOSFET 11. MOSFET is an abbreviation for Metal Oxide Semiconductor Field Effect Transistor. The three high-side MOSFETs 11 connected in parallel are turned on and off at the same timing by a common gate drive signal (drive voltage). The three low-side MOSFETs 11 connected in parallel are turned on and off at the same timing by a common gate drive signal (drive voltage).

[0024] Each MOSFET 11 has a freewheeling diode 12 connected in antiparallel. Diode 12 may be a parasitic diode (body diode) or an external diode. In the upper arm 9H, the drain of MOSFET 11 is connected to the P line 7. In the lower arm 9L, the source of MOSFET 11 is connected to the N line 8. The source of MOSFET 11 in the upper arm 9H and the drain of MOSFET 11 in the lower arm 9L are interconnected. The anode of diode 12 is connected to the source of the corresponding MOSFET 11, and its cathode is connected to the drain.

[0025] Note that the switching element is not limited to MOSFET 11. 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.

[0026] As illustrated in Figure 1, the power conversion circuit 4 includes a filter circuit 17. The filter circuit 17 is a circuit for reducing noise such as electromagnetic noise. The filter circuit 17 is sometimes called an EMI filter. EMI is an abbreviation for Electromagnetic Interference. The filter circuit 17 is connected in parallel to the smoothing capacitor 5 and the inverter 6. The filter circuit 17 is installed between the DC power supply 2 and the smoothing capacitor 5. The filter circuit 17 includes coils, capacitors, etc.

[0027] The example filter circuit 17 includes a choke coil 18 and a Y capacitor 19. The filter circuit 17 is, for example, an LCL filter. The choke coil 18 may also be called a common mode coil, filter core, EMI core, etc. The choke coil 18 and the Y capacitor 19 reduce common mode noise. The filter circuit 17 may also have an X capacitor or a normal mode coil to reduce normal mode noise.

[0028] The power conversion circuit 4 may further include a converter. The converter is a DC-DC converter that converts a DC voltage to, for example, a DC voltage of a different value. The converter is provided between the DC power supply 2 and the smoothing capacitor 5. The converter is configured, for example, with a reactor and the above-described up-and-down arm circuit 9. With this configuration, step-up and step-down voltage conversion is possible. The power conversion circuit 4 may also include a filter capacitor that removes power supply noise from the DC power supply 2. The filter capacitor is provided between the DC power supply 2 and the converter.

[0029] The power conversion circuit 4 may include a drive circuit for the switching elements that make up the inverter 6, etc. The drive circuit supplies a drive voltage to the gate of the corresponding arm's MOSFET 11 based on a drive command from the control circuit. The drive circuit drives the corresponding MOSFET 11, i.e., turns it on or off, by applying the drive voltage. The drive circuit is sometimes referred to as a driver.

[0030] The power conversion circuit 4 may include a control circuit for the switching element. The control circuit generates a drive command for operating the MOSFET 11 and outputs it to the drive circuit. The control circuit generates the drive command based on, for example, a torque request input from a higher-level ECU (not shown) and signals detected by various sensors. ECU is an abbreviation for Electronic Control Unit.

[0031] Various types of sensors include, for example, current sensors, rotation angle sensors, and voltage sensors. The current sensor detects the phase current flowing through the windings 3a of each phase. 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 5. 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 memory. PWM is an abbreviation for Pulse Width Modulation.

[0032] The power conversion circuit 4 may include a snubber circuit. The snubber circuit is connected in parallel to the upper and lower arm circuit 9. The snubber circuit reduces the inductance of the upper and lower arm circuit 9. The snubber circuit absorbs transient high voltages, so-called switching surges, that occur when the switching elements (MOSFETs 11) constituting the upper and lower arm circuit 9 are switched. By providing a snubber circuit, the inverter 6 can switch at high speed.

[0033] <Power Conversion Device> In the following, the three directions that are orthogonal to each other are referred to as the X direction, Y direction, and Z direction. The X direction is the direction in which the first P busbar 41P and the first N busbar 41N extend. The Z direction is the plate thickness direction of each busbar. The Y direction is the direction perpendicular to the X direction and the Z direction. The Y direction corresponds to a predetermined direction in which the second P busbar 42P and the second N busbar 42N extend.

[0034] The power converter 20 provides the power conversion circuit 4 described above. The power converter 20 comprises an inverter 6, a noise filter 30, a cooler 22, and a housing 21. For example, the inverter 6 and the noise filter 30 are housed in the housing 21. The inverter 6 may be housed in the housing 21, and the noise filter 30 may be housed in a separate housing.

[0035] The inverter 6 converts power through switching operation. The cooler 22 cools the inverter 6. The cooler 22 cools, for example, the power modules that make up the inverter 6. The cooler 22 is made of a metal material such as aluminum. The cooler 22 may be at least a part of the housing 21, or it may be provided separately from the housing 21. The example cooler 22 is part of the housing 21. The cooler 22 may be made of a single component, or it may be made by assembling multiple components.

[0036] The cooler 22 has a refrigerant flow path 23 through which the refrigerant flows. The refrigerant may be a phase-changing refrigerant such as water or ammonia, or a non-phase-changing refrigerant such as ethylene glycol. The refrigerant may also be LLC. LLC is an abbreviation for long life coolant. The cooler 22 may also be a heat sink. The heat sink may have fins on its back side.

[0037] The noise filter 30 provides the filter circuit 17. The noise filter 30 suppresses electromagnetic noise. The noise filter 30 in this embodiment reduces common-mode noise. The cooler 22 and the noise filter 30 may be located in positions that overlap or do not overlap in the Z-direction view. In other words, the refrigerant flow path 23 and the noise filter 30 may or may not overlap in the Z-direction view. In this embodiment, for example, the refrigerant flow path 23 and the noise filter 30 do not overlap in the Z-direction view. The noise filter 30 will be described in detail later.

[0038] <Noise Filter> Figure 2 is a perspective view showing an example of a noise filter. Figure 3 is a perspective view of the noise filter of Figure 2 from the opposite side in the Z direction. Figure 4 is a schematic plan view showing the structure of the noise filter. Figure 5 is a view of the power converter 20 from the Y direction.

[0039] The noise filter 30 comprises a main body 31, a core 50, a P-side capacitor 60P, an N-side capacitor 60N, a P-side connector 45P, an N-side connector 45N, and busbars. The busbars include a first P-busbar 41P, a first N-busbar 41N, a second P-busbar 42P, a second N-busbar 42N, a third P-busbar 43P, a third N-busbar 43N, a P-side ground busbar 44P, and an N-side ground busbar 44N. In the following description, P-side and N-side components may be described together. For example, the first P-busbar 41P and the first N-busbar 41N may be described as first busbars 41P and 41N.

[0040] The main body 31 is made of, for example, resin. The main body 31 may be made of a single component or of multiple components assembled together. The main body 31 fixes the other elements that make up the noise filter 30. For example, the core 50, busbar, P-side connector 45P, and N-side connector 45N are fixed to the main body 31.

[0041] The core 50 and the first busbars 41P and 41N provide the choke coil 18. The core 50 is, for example, an annular member made of a magnetic material. Specific examples of magnetic materials include iron-based metals and ferrite. The core 50 has a through hole, and the first P busbar 41P and the first N busbar 41N pass through the core 50. The through hole in the core 50 penetrates, for example, in the X direction. The exemplary noise filter 30 has two cores, and the first P busbar 41P and the first N busbar 41N pass through the two cores 50. The number of cores 50 is not limited by this embodiment; there may be one or more.

[0042] The busbars are metal plates made of a metal with good conductivity, such as Cu. Each busbar is arranged such that, for example, its thickness direction is parallel to the Z direction. The first P busbar 41P and the first N busbar 41N are arranged to extend in the X direction. The first P busbar 41P is the input line on the high potential side. The first N busbar 41N is the input line on the low potential side. The first P busbar 41P and the first N busbar 41N are arranged side by side in the Y direction, for example. Here, for the first P busbar 41P and the first N busbar 41N to be arranged side by side in the Y direction, it is sufficient that at least a portion of each of the first P busbar 41P and the first N busbar 41N are aligned in the Y direction. The side surfaces of the first P busbar 41P and the first N busbar 41N face each other. The Z-direction positions of the first P busbar 41P and the first N busbar 41N are approximately the same.

[0043] The second P bus bar 42P branches off from the first P bus bar 41P and is arranged to extend along the Y direction. The second N bus bar 42N branches off from the first N bus bar 41N, and is arranged side by side with the second P bus bar 42P so as to extend along the Y direction. That is, the second P bus bar 42P and the second N bus bar 42N extend in the same direction and are arranged side by side. In the present embodiment, the second P bus bar 42P and the second N bus bar 42N are arranged between the two cores 50 in the X direction. The second P bus bar 42P and the second N bus bar 42N are arranged side by side in the X direction, for example. The side surface of the second P bus bar 42P and the side surface of the second N bus bar 42N face each other. The positions in the Z direction of the second P bus bar 42P and the second N bus bar 42N are substantially the same.

[0044] Here, the expression that the second P bus bar 42P and the second N bus bar 42N are arranged side by side means that at least a part of each of the second P bus bar 42P and the second N bus bar 42N only needs to be arranged side by side. In addition, the expression that the second P bus bar 42P and the second N bus bar 42N extend in the Y direction means that at least a part of each of the second P bus bar 42P and the second N bus bar 42N only needs to extend in the Y direction. That is, the second P bus bar 42P and the second N bus bar 42N may have portions extending in directions other than the Y direction. In the example shown in FIG. 2, the second P bus bar 42P and the second N bus bar 42N each have a portion extending in the Y direction and a portion extending in the X direction.

[0045] The third P bus bar 43P is connected to the second P bus bar 42P, and is arranged to extend to the side opposite to the second N bus bar 42N with respect to the second P bus bar 42P. That is, the third P bus bar 43P is connected to the second P bus bar 42P and extends in the direction away from the second N bus bar 42N. The third P bus bar 43P is connected to the portion of the second P bus bar 42P that extends in the Y direction.

[0046] The third N bus bar 43N is connected to the second N bus bar 42N, and is arranged to extend to the side opposite to the second P bus bar 42P with respect to the second N bus bar 42N. That is, the third N bus bar 43N is connected to the second N bus bar 42N and extends in the direction away from the second P bus bar 42P. The third N bus bar 43N is connected to the portion of the second N bus bar 42N that extends in the Y direction.

[0047] The third P bus bar 43P and the third N bus bar 43N each extend in a direction away from the connection point with the second P bus bar 42P and the second N bus bar 42N, respectively. As shown in FIG. 4, in the present embodiment, the third P bus bar 43P extends in the X direction. The third N bus bar 43N extends in the X direction on the side opposite to the direction in which the third P bus bar 43P extends. Note that the direction in which the third P bus bar 43P and the third N bus bar 43N extend is not limited to the X direction. Further, in the present embodiment, the directions in which the third P bus bar 43P and the third N bus bar 43N extend are parallel to each other. However, the directions in which the third P bus bar 43P and the third N bus bar 43N extend do not have to be parallel to each other.

[0048] The number of the third P bus bars 43P and the number of the third N bus bars 43N may each be one, or may each be a plurality. The numbers of the third P bus bars 43P and the third N bus bars 43N are, for example, equal. In the present embodiment, three third P bus bars 43P and three third N bus bars 43N are provided respectively. Each third P bus bar 43P extends, for example, in the same direction. The respective third P bus bars 43P are arranged side by side in the Y direction so as to be parallel to each other. Similarly, each third N bus bar 43N extends, for example, in the same direction. The respective third N bus bars 43N are arranged side by side in the Y direction so as to be parallel to each other. Note that the respective third P bus bars 43P may extend in directions different from each other. The respective third N bus bars 43N may extend in directions different from each other.

[0049] In the present embodiment, the length of each third P bus bar 43P is the same. The length of each third N bus bar 43N is the same. The lengths of the third P bus bar 43P and the third N bus bar 43N are the same. Note that the lengths of the respective third P bus bars 43P may be different from each other. The lengths of the respective third N bus bars 43N may be different from each other. The lengths of the third P bus bar 43P and the third N bus bar 43N may be different from each other.

[0050] The first P busbar 41P, the second P busbar 42P, and the third P busbar 43P may be a single unit, or they may be separate units connected by welding or fastening members. In this embodiment, the second P busbar 42P is separate from the first P busbar 41P and is welded to the first P busbar 41P. The second P busbar 42P and the third P busbar 43P are a single unit. Similarly, the first N busbar 41N, the second N busbar 42N, and the third N busbar 43N may be a single unit, or they may be separate units connected by welding or fastening members. In this embodiment, the second N busbar 42N is separate from the first N busbar 41N and is welded to the first N busbar 41N. The second N busbar 42N and the third N busbar 43N are a single unit.

[0051] The thicknesses of the first P busbar 41P, the second P busbar 42P, and the third P busbar 43P may be the same or different. Here, the thickness of each busbar refers to the length in the direction perpendicular to both the thickness direction of each busbar and the direction in which each busbar extends. Alternatively, the thickness of each busbar may refer to the cross-sectional area. In this embodiment, the third P busbar 43P is thinner than the second P busbar 42P. The second P busbar 42P is thinner than the first P busbar 41P.

[0052] Similarly, the thicknesses of the first N busbar 41N, the second N busbar 42N, and the third N busbar 43N may be the same or different. In this embodiment, the third N busbar 43N is thinner than the second N busbar 42N. The second N busbar 42N is thinner than the first N busbar 41N. The thicknesses of the first P busbar 41P and the first N busbar 41N are, for example, the same. The thicknesses of the second P busbar 42P and the second N busbar 42N are, for example, the same. The thicknesses of the third P busbar 43P and the third N busbar 43N are, for example, the same.

[0053] The P-side capacitor 60P and the N-side capacitor 60N provide the Y-capacitor 19. The P-side capacitor 60P and the N-side capacitor 60N each have a capacitor body 60a and a pair of terminals 60b. The pair of terminals 60b correspond to one end and the other end of the capacitors 60P and 60N. One terminal of the P-side capacitor 60P is connected to the third P-busbar 43P. The other terminal of the P-side capacitor 60P is connected to the P-side ground busbar 44P, which will be described later. One end of the P-side capacitor 60P is connected to the third P-busbar 43P to remove electromagnetic noise. Each terminal 60b of the P-side capacitor 60P is welded to the third P-busbar 43P and the P-side ground busbar 44P.

[0054] Similarly, one terminal of the N-side capacitor 60N is connected to the third N-busbar 43N. The other terminal of the N-side capacitor 60N is connected to the N-side ground busbar 44N, which will be described later. One end of the N-side capacitor 60N is connected to the third N-busbar 43N to remove electromagnetic noise. Each terminal 60b of the N-side capacitor 60N is welded to the third N-busbar 43N and the N-side ground busbar 44N.

[0055] The number of P-side capacitors 60P and N-side capacitors 60N may be one each or multiple each. The number of P-side capacitors 60P is equal to the number of third P busbars 43P. The number of N-side capacitors 60N is equal to the number of third N busbars 43N. As mentioned above, in this embodiment, three third P busbars 43P and three third N busbars 43N are provided. Therefore, in this embodiment, three P-side capacitors 60P and three N-side capacitors 60N are provided. As shown in Figure 3, the P-side capacitors 60P are arranged in a line in the Y direction. The N-side capacitors 60N are arranged in a line in the Y direction.

[0056] Of the multiple P-side capacitors 60P, at least one has a different capacitance from the other P-side capacitors. In this embodiment, the three P-side capacitors 60P each have different capacitances. The P-side capacitors 60P include the smallest capacitance, minimum P-side capacitor 61P, and the largest capacitance, maximum P-side capacitor 62P.

[0057] Similarly, at least one of the multiple N-side capacitors 60N has a different capacitance from the other N-side capacitors. In this embodiment, the three N-side capacitors 60N each have different capacitances. The N-side capacitors 60N include the smallest N-side capacitor 61N with the smallest capacitance and the largest N-side capacitor 62N with the largest capacitance.

[0058] The capacitance of each P-side capacitor 60P may be the same as the capacitance of each N-side capacitor. In other words, the capacitance of each P-side capacitor 60P may be the same as the capacitance of the corresponding N-side capacitor. For example, the capacitance of the smallest P-side capacitor 61P and the smallest N-side capacitor 61N are the same. Also, the capacitance of the largest P-side capacitor 62P and the largest N-side capacitor 62N are the same.

[0059] As shown in Figure 4, the distance L4 from the smallest P-side capacitor 61P to the first P-busbar 41P is shorter than the distance from the other P-side capacitors to the first P-busbar 41P. In other words, the shortest distance from each P-side capacitor 60P to the first P-busbar 41P is the distance L4 from the smallest P-side capacitor 61P to the first P-busbar 41P. Here, distance refers to the path length of the busbar. That is, the distance L4 from the smallest P-side capacitor 61P to the first P-busbar 41P refers to the path length from the smallest P-side capacitor 61P to the first P-busbar 41P. P-side capacitors 60P are placed closer to the first P-busbar 41P the smaller their capacitance is, for example. In other words, the distance from the P-side capacitor 60P to the first P-busbar 41P is shorter the smaller the capacitance of the capacitor.

[0060] Similarly, the distance L5 from the smallest N-side capacitor 61N to the first N-busbar 41N is shorter than the distance from any other N-side capacitor to the first N-busbar 41N. In other words, the shortest distance from each N-side capacitor 60N to the first N-busbar 41N is the distance L5 from the smallest N-side capacitor 61N to the first N-busbar 41N. Here, the distance L5 from the smallest N-side capacitor 61N to the first N-busbar 41N refers to the path length from the smallest N-side capacitor 61N to the first N-busbar 41N. N-side capacitors 60N are positioned closer to the first N-busbar 41N the smaller their capacitance, for example. In other words, the distance from the N-side capacitor 60N to the first N-busbar 41N is shorter the smaller the capacitance of the capacitor.

[0061] The P-side ground busbar 44P is connected to terminal 60b of the P-side capacitor 60P. The N-side ground busbar 44N is connected to terminal 60b of the N-side capacitor 60N. The number of P-side ground busbars 44P and N-side ground busbars 44N is equal to the number of P-side capacitors 60P and N-side capacitors 60N. As mentioned above, in this embodiment, three P-side capacitors 60P and three N-side capacitors 60N are provided. Therefore, in this embodiment, three P-side ground busbars 44P and three N-side ground busbars 44N are provided. The P-side ground busbar 44P connects the other end of the P-side capacitor to a grounding member that provides ground potential. The N-side ground busbar 44N connects the other end of the N-side capacitor to a grounding member that provides ground potential.

[0062] Multiple P-side ground busbars 44P are connected by P-side connecting portions 45P. Multiple N-side ground busbars 44N are connected by N-side connecting portions 45N. The P-side connecting portions 45P and N-side connecting portions 45N are made of, for example, a metal material with good conductivity. Multiple P-side ground busbars 44P and one P-side connecting portion 45P are integrally formed by press molding a single metal plate. Multiple N-side ground busbars 44N and N-side connecting portions 45N are similarly integrally formed.

[0063] There is one P-side connector 45P and one N-side connector 45N. Each P-side ground busbar 44P has one end connected to the terminal 60b of each P-side capacitor 60P and the other end connected to the P-side connector 45P. Each N-side ground busbar 44N has one end connected to the terminal 60b of each N-side capacitor 60N and the other end connected to the N-side connector 45N.

[0064] Each P-side grounding busbar 44P and P-side connecting portion 45P may be a single unit, or they may be separate and connected by welding or fastening members. Each N-side grounding busbar 44N and N-side connecting portion 45N may be a single unit, or they may be separate and connected by welding or fastening members.

[0065] The P-side connecting portion 45P connects a plurality of P-side grounding busbars 44P and has a P-side grounding portion 46P that is connected to a grounding member. The N-side connecting portion 45N connects a plurality of N-side grounding busbars 44N and has an N-side grounding portion 46N that is connected to a grounding member. In other words, the P-side grounding portion 46P is electrically connected to the P-side grounding busbars 44P and connected to the grounding member. The N-side grounding portion 46N is electrically connected to the N-side grounding busbars 44N and connected to the grounding member. There is one P-side grounding portion 46P and one N-side grounding portion 46N each. The grounding member is, for example, the housing 21. In this embodiment, the housing 21 corresponds to the grounding member that provides the ground potential. The P-side grounding portion 46P and the N-side grounding portion 46N are, for example, through holes.

[0066] As shown in Figure 5, the P-side grounding portion 46P and the N-side grounding portion 46N are connected to the housing 21 by fastening members such as bolts 47. In other words, each P-side capacitor 60P is connected to the housing 21 via each P-side grounding busbar 44P and P-side connecting portion 45P. Each N-side capacitor 60N is connected to the housing 21 via each N-side grounding busbar 44N and N-side connecting portion 45N. The P-side grounding portion 46P and the N-side grounding portion 46N are connected to different positions on the housing 21.

[0067] In this embodiment, the distance from the largest P-side capacitor 62P to the P-side ground point 46P is shorter than the distance from the other P-side capacitors to the P-side ground points 46P. In other words, the shortest distance from each P-side capacitor 60P to the P-side ground point 46P is the distance from the largest P-side capacitor 62P to the P-side ground point 46P.

[0068] Similarly, the distance from the largest N-side capacitor 62N to the N-side ground 46N is shorter than the distance from the other N-side capacitors to the N-side ground 46N. In other words, the shortest distance from each N-side capacitor 60N to the N-side ground 46N is the distance from the largest N-side capacitor 62N to the N-side ground 46N.

[0069] The distance from each P-side capacitor 60P to the P-side grounding point 46P is the shortest path length described below. In other words, it is the shortest path length along each P-side grounding busbar 44P and P-side connecting point 45P from the connection point between the terminal 60b of each P-side capacitor 60P and each P-side grounding busbar 44P to the P-side grounding point 46P. The distance from each N-side capacitor 60N to the N-side grounding point 46N is the shortest path length described below. In other words, it is the shortest path length along each N-side grounding busbar 44N and N-side connecting point 45N from the connection point between the terminal 60b of each N-side capacitor 60N and each N-side grounding busbar 44N to the N-side grounding point 46N.

[0070] Furthermore, as shown in Figure 2, the distance L1 from the P-side grounding point 46P to the refrigerant flow path 23 is shorter than the distance L2 from the first P busbar 41P to the refrigerant flow path 23. Here, distance refers to the straight-line distance. In other words, distance L1 is the shortest distance from the P-side grounding point 46P to the refrigerant flow path 23. Distance L2 is the shortest distance from the first P busbar 41P to the refrigerant flow path 23. Similarly, on the N side, the distance from the N-side grounding point 46N to the refrigerant flow path 23 is shorter than the distance from the first N busbar 41N to the refrigerant flow path 23. In other words, the shortest distance from the N-side grounding point 46N to the refrigerant flow path 23 is shorter than the shortest distance from the first N busbar 41N to the refrigerant flow path 23.

[0071] Furthermore, as shown in Figure 3, the distance L3 from the P-side condenser 60P to the refrigerant flow path 23 is shorter than the distance L2 from the first P busbar 41P to the refrigerant flow path 23. Here, the distance also refers to the straight-line distance. In other words, distance L3 is the shortest distance from the P-side condenser 60P to the refrigerant flow path 23. Similarly for the N-side, the distance from the N-side condenser 60N to the refrigerant flow path 23 is shorter than the distance from the first N busbar 41N to the refrigerant flow path 23. In other words, the shortest distance from the N-side condenser 60N to the refrigerant flow path 23 is shorter than the shortest distance from the first N busbar 41N to the refrigerant flow path 23.

[0072] The above-mentioned relationships between the various distances only need to hold true for at least one of the three capacitors 60P and 60N. In this embodiment, the above-mentioned conditions hold true for all P-side capacitors 60P and all N-side capacitors 60N. Each grounding section 46P and 46N is positioned, for example, between the refrigerant flow path 23 and the first busbars 41P and 41N when viewed in the Z direction. Each capacitor 60P and 60N is positioned, for example, between the refrigerant flow path 23 and the first busbar 41P when viewed in the Z direction.

[0073] <Effects of the First Embodiment> According to this disclosure, the noise filter 30 comprises a first P busbar 41P, a first N busbar 41N, a second P busbar 42P, a second N busbar 42N, a third P busbar 43P, a third N busbar 43N, a P-side ground busbar 44P, an N-side ground busbar 44N, a P-side capacitor 60P, and an N-side capacitor 60N. The second P busbar 42P and the second N busbar 42N are arranged side by side so as to extend in the Y direction. As a result, the magnetic fluxes generated by the currents flowing through the second P busbar 42P and the second N busbar 42N cancel each other out, thereby reducing the inductance.

[0074] Furthermore, the P-side ground busbar 44P and the N-side ground busbar 44N are connected to different positions on the grounding member. This reduces the amount of current flowing through the busbars connected to the grounding member compared to, for example, the case where the P-side capacitor 60P and the N-side capacitor 60N are connected to the same busbar and at the same position. In other words, the amount of heat generated by the busbars can be suppressed.

[0075] Furthermore, the third P busbar 43P is connected to the second P busbar 42P on the opposite side from the second N busbar 42N. The third N busbar 43N is connected to the second N busbar 42N on the opposite side from the second P busbar 42P. Therefore, by adjusting the lengths of the third P busbar 43P and the third N busbar 43N, heat can be dissipated evenly on the P side and the N side. Contrary to this disclosure, if the third P busbar 43P and the third N busbar 43N are placed on the same side, it becomes necessary to straddle the second P busbar 42P or the second N busbar 42N. Therefore, the arrangement of the third P busbar 43P and the third N busbar 43N tends to become complicated. According to this disclosure, the above problems can be solved. Furthermore, compared to the case where the third P busbar 43P and the third N busbar 43N are placed on the same side, dead space can be reduced and the noise filter 30 can be miniaturized.

[0076] Furthermore, according to this disclosure, multiple third P busbars 43P, third N busbars 43N, P-side ground busbars 44P, N-side ground busbars 44N, P-side capacitors 60P, and N-side capacitors 60N are provided. At least one of the multiple P-side capacitors 60P has a different capacitance from the other P-side capacitors. Also, at least one of the multiple N-side capacitors 60N has a different capacitance from the other N-side capacitors 60N. This allows for a noise bypass effect over a wide bandwidth. In addition, as mentioned above, since the second P busbar 42P and the second N busbar 42N are arranged side by side, the inductance can be reduced by canceling out the magnetic flux. In other words, a noise bypass effect can be achieved over a wide bandwidth while suppressing the increase in inductance.

[0077] Furthermore, according to this disclosure, a P-side connecting section 45P is provided, which connects a plurality of P-side grounding busbars 44P and has a P-side grounding section 46P that is connected to a grounding member. In addition, an N-side connecting section 45N is provided, which connects a plurality of N-side grounding busbars 44N and has an N-side grounding section that is connected to a grounding member. Conversely, if there are no connecting sections 45P and 45N, each of the plurality of grounding busbars 44P and 44N will be provided with a grounding section 46P and 46N. In contrast, according to this disclosure, compared to the case where multiple P-side grounding sections 46P and N-side grounding sections 46N are provided, the number of points where each grounding busbar 44P and 44N is connected to the grounding member can be reduced, thus improving the workability of the connection.

[0078] Furthermore, according to this disclosure, the distance from the maximum P-side capacitor 62P to the P-side grounding point 46P is shorter than the distance from other P-side capacitors to the P-side grounding point 46P. Also, the distance from the maximum N-side capacitor 62N to the N-side grounding point 46N is shorter than the distance from other N-side capacitors to the N-side grounding point 46N. Here, as the capacitance of the capacitor increases, the current flowing through it increases, so each maximum capacitor 62P, 62N tends to become hot. According to this disclosure, since the grounding member is connected near each maximum capacitor 62P, 62N, heat can be easily dissipated.

[0079] Furthermore, according to this disclosure, the distance from the smallest P-side capacitor 61P to the first P-busbar 41P is shorter than the distance from other P-side capacitors to the first P-busbar 41P. Also, the distance from the smallest N-side capacitor 61N to the first N-busbar 41N is shorter than the distance from other N-side capacitors to the first N-busbar 41N. Here, as the length of the busbar increases, the parasitic inductance increases and the resonant frequency changes. Capacitors with smaller capacitance are more susceptible to the above effects. According to this disclosure, since the smallest capacitors 61P and 61N are placed close to the first busbars 41P and 41N, the above effects can be suppressed.

[0080] Furthermore, according to this disclosure, the third P busbar 43P is narrower than the second P busbar 42P. The third N busbar 43N is narrower than the second N busbar 42N. Here, if there are multiple third busbars 43P and 43N, the current flowing through the second busbars 42P and 42N is branched to each of the third busbars 43P and 43N. In other words, if there are multiple third busbars 43P and 43N, the amount of current flowing through each of the third busbars 43P and 43N is smaller than the amount of current flowing through the second busbars 42P and 42N. Therefore, the third busbars 43P and 43N can be made narrower than the second busbars 42P and 42N. According to this disclosure, the amount of busbars used can be reduced, which can lead to miniaturization of the noise filter and cost reduction.

[0081] Furthermore, according to this disclosure, the second P busbar 42P is thinner than the first P busbar 41P. The second N busbar 42N is thinner than the first N busbar 41N. Here, a large DC current flows through the first busbars 41P and 41N, while only the AC component flows through the second busbars 42P and 42N. Therefore, the amount of current flowing through the second busbars 42P and 42N is smaller than the amount of current flowing through the first busbars 41P and 41N. As a result, the second busbars 42P and 42N can be made thinner than the first busbars 41P and 41N. This disclosure also reduces the amount of busbars used, enabling miniaturization of the noise filter and cost reduction.

[0082] Furthermore, according to this disclosure, the power converter 20 includes a cooler 22 having a refrigerant flow path 23 for cooling the inverter 6. The distance from the P-side grounding portion 46P to the refrigerant flow path 23 is shorter than the distance from the first P busbar 41P to the refrigerant flow path 23. Also, the distance from the N-side grounding portion 46N to the refrigerant flow path 23 is shorter than the distance from the first N busbar 41N to the refrigerant flow path 23. As a result, the P-side grounding portion 46P and the N-side grounding portion 46N can be cooled by the refrigerant flow path 23, and consequently the temperatures of the P-side capacitor 60P and the N-side capacitor 60N can be reduced.

[0083] Furthermore, according to this disclosure, the distance from the P-side condenser 60P to the refrigerant flow path 23 is shorter than the distance from the first P busbar 41P to the refrigerant flow path 23. Also, the distance from the N-side condenser 60N to the refrigerant flow path 23 is shorter than the distance from the first N busbar 41N to the refrigerant flow path 23. As a result, the P-side condenser 60P and the N-side condenser 60N can be cooled by the refrigerant flow path 23.

[0084] (Other Embodiments) The disclosures of this specification are not limited to the exemplary embodiments. The disclosures encompass the exemplary embodiments and variations thereof by those skilled in the art. For example, the disclosures are not limited to the combinations of parts and elements shown in the embodiments, but can be implemented in various variations. The disclosures can be implemented in a variety of combinations. The disclosures may have additional parts that can be added to the embodiments. The disclosures encompass embodiments in which parts and elements have been omitted. The disclosures encompass substitutions or combinations of parts and elements between one embodiment and another. The scope of the disclosed technical field is not limited to the descriptions of the embodiments. The scope of the disclosed technical field is indicated by the claims and should be understood to include all modifications within the meaning and scope equivalent to the claims.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] In the above embodiment, the third busbars 43P and 43N are thinner than the second busbars 42P and 42N. Also, the second busbars 42P and 42N are thinner than the first busbars 41P and 41N. However, the thicknesses of the first P busbar 41P, the second P busbar 42P, and the third P busbar 43P may be equal. Also, the thicknesses of the first N busbar 41N, the second N busbar 42N, and the third N busbar 43N may be equal. This makes it possible to reduce the resistance values ​​of the second busbars 42P and 42N and the third busbars 43P and 43N, thereby suppressing heat generation.

[0089] In the above embodiment, capacitors with smaller capacitances are placed closer to the first busbars 41P and 41N. That is, the path length from the capacitor to the first busbars 41P and 41N is shorter as the capacitance of the capacitor decreases. However, the placement of the capacitors is not limited to the above.

[0090] In the above embodiment, the distance from the largest capacitors 62P, 62N to the ground points 46P, 46N is shorter than the distance from the other capacitors 60P, 60N to the ground points 46P, 46N. However, the positions of the P-side ground point 46P and the N-side ground point 46N are not limited to the above. For example, the P-side ground point 46P may be located near the P-side capacitor that is closest to the first P-busbar 41P. In other words, the distance from the P-side capacitor that is closest to the first P-busbar 41P to the P-side ground point 46P may be shorter than the distance from the other P-side capacitors to the P-side ground point 46P. In the example shown in Figure 3, the smallest P-side capacitor 61P corresponds to the P-side capacitor that is closest to the first P-busbar 41P. Similarly, on the N side, the distance from the N-side capacitor 60N that is closest to the first N-busbar 41N to the N-side ground point 46N may be shorter than the distance from the other N-side capacitors to the N-side ground point 46N.

[0091] Here, a large current flows through the first P busbar 41P and the first N busbar 41N, making them prone to overheating. As a result, capacitors placed near the first P busbar 41P and the first N busbar 41N are susceptible to the effects of this heat. As described above, by providing grounding points 46P and 46N near the capacitors, heat can be easily dissipated.

[0092] In the above embodiment, the distance from the grounding points 46P and 46N to the refrigerant flow path 23 is shorter than the distance from the first busbars 41P and 41N to the refrigerant flow path 23. Also, the distance from the condensers 60P and 60N to the refrigerant flow path 23 is shorter than the distance from the first busbars 41P and 41N to the refrigerant flow path 23. However, the distance from the first P busbar 41P to the refrigerant flow path 23 may be shorter than the distance from the P-side grounding point 46P to the refrigerant flow path 23. Also, the distance from the first P busbar 41P to the refrigerant flow path 23 may be shorter than the distance from the P-side condenser 60P to the refrigerant flow path 23. The same applies to the N side.

[0093] As described above, the first P busbar 41P and the first N busbar 41N tend to generate heat because large currents flow through them. As shown in the structure above, by arranging the first P busbar 41P and the first N busbar 41N near the refrigerant flow path 23, heat can be easily dissipated.

[0094] In the above embodiment, the noise filter 30 includes a P-side connecting section 45P that connects a plurality of P-side ground busbars 44P and has a P-side grounding section 46P. However, the P-side connecting section 45P is not required. That is, each of the plurality of P-side ground busbars 44P may have a P-side grounding section that is connected to a grounding member. Similarly, the N-side connecting section 45N is not required for the N-side. That is, each of the plurality of N-side ground busbars 44N may have an N-side grounding section that is connected to a grounding member. Also, if there is only one P-side ground busbar 44P, a P-side grounding section 46P may be provided on the P-side ground busbar 44P. Similarly, if there is only one N-side ground busbar 44N, an N-side grounding section 46N may be provided on the N-side ground busbar 44N.

[0095] (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.

[0096] (Technical Concept 1) A first P busbar (41P) which is an input line on the high potential side, a first N busbar (41N) which is an input line on the low potential side, a second P busbar (42P) which branches off from the first P busbar and is arranged to extend along a predetermined direction, a second N busbar (42N) which branches off from the first N busbar and is arranged alongside the second P busbar and extends along the predetermined direction, a third P busbar (43P) which is connected to the second P busbar and is arranged to extend on the opposite side of the second N busbar relative to the second P busbar, a third N busbar (43N) which is connected to the second N busbar and is arranged to extend on the opposite side of the second P busbar relative to the second N busbar, a P-side capacitor (60P) which has one end connected to the third P busbar to remove electromagnetic noise, and an N-side capacitor (60N) which has one end connected to the third N busbar to remove electromagnetic noise. A noise filter comprising a P-side ground busbar (44P) connected to a grounding member (21) that provides a ground potential, to which the other end of the P-side capacitor is connected, and an N-side ground busbar (44N) connected to the other end of the N-side capacitor is connected to the grounding member, wherein the P-side ground busbar and the N-side ground busbar are connected to different positions on the grounding member.

[0097] (Technical Concept 2) The noise filter according to Technical Concept 1, wherein a plurality of the third P busbar, the third N busbar, the P-side ground busbar, the N-side ground busbar, the P-side capacitor, and the N-side capacitor are provided, at least one of the plurality of P-side capacitors has a different capacitance from the other P-side capacitors, and at least one of the plurality of N-side capacitors has a different capacitance from the other N-side capacitors.

[0098] (Technical Concept 3) A noise filter according to Technical Concept 2, comprising: a P-side connecting section (45P) that connects a plurality of P-side ground busbars and has a P-side ground section (46P) connected to the grounding member; and an N-side connecting section (45N) that connects a plurality of N-side ground busbars and has an N-side ground section (46N) connected to the grounding member.

[0099] (Technical idea 4) A noise filter as described in technical idea 3, wherein the P-side capacitor with the largest capacitance among the multiple P-side capacitors is designated as the maximum P-side capacitor (62P), the N-side capacitor with the largest capacitance among the multiple N-side capacitors is designated as the maximum N-side capacitor (62N), the distance from the maximum P-side capacitor to the P-side ground is shorter than the distance from the other P-side capacitors to the P-side ground, and the distance from the maximum N-side capacitor to the N-side ground is shorter than the distance from the other N-side capacitors to the N-side ground.

[0100] (Technical Idea 5) A noise filter according to any one of Technical Ideas 2 to 4, wherein the P-side capacitor with the smallest capacitance among the plurality of P-side capacitors is designated as the minimum P-side capacitor (61P), the N-side capacitor with the smallest capacitance among the plurality of N-side capacitors is designated as the minimum N-side capacitor (61N), the distance from the minimum P-side capacitor to the first P-busbar is shorter than the distance from the other P-side capacitors to the first P-busbar, and the distance from the minimum N-side capacitor to the first N-busbar is shorter than the distance from the other N-side capacitors to the first N-busbar.

[0101] (Technical Idea 6) A noise filter according to any one of Technical Ideas 2 to 5, wherein the third P busbar is thinner than the second P busbar, and the third N busbar is thinner than the second N busbar.

[0102] (Technical Idea 7) A noise filter according to any one of Technical Ideas 1 to 6, wherein the second P busbar is thinner than the first P busbar, and the second N busbar is thinner than the first N busbar.

[0103] (Technical Idea 8) A noise filter according to any one of Technical Ideas 1 to 5, wherein the thickness of the first P busbar, the second P busbar, and the third P busbar are equal, and the thickness of the first N busbar, the second N busbar, and the third N busbar are equal.

[0104] (Technical Concept 9) A power conversion device having an inverter (6) that converts power by switching operation and a noise filter (30), wherein the noise filter includes a first P busbar (41P) which is an input line on the high potential side, a first N busbar (41N) which is an input line on the low potential side, a second P busbar (42P) which branches off from the first P busbar and is arranged to extend along a predetermined direction, a second N busbar (42N) which branches off from the first N busbar and is arranged alongside the second P busbar and extends along the predetermined direction, a third P busbar (43P) which is connected to the second P busbar and is arranged to extend on the opposite side of the second N busbar relative to the second P busbar, and a third N busbar (43N) which is connected to the second N busbar and is arranged to extend on the opposite side of the second P busbar relative to the second N busbar, A power converter comprising: a P-side capacitor (60P) with one end connected to the third P-busbar to remove electromagnetic noise; an N-side capacitor (60N) with one end connected to the third N-busbar to remove electromagnetic noise; a P-side ground busbar (44P) to which the other end of the P-side capacitor is connected to a grounding member (21) that provides a ground potential; and an N-side ground busbar (44N) to which the other end of the N-side capacitor is connected to the grounding member, wherein the P-side ground busbar and the N-side ground busbar are connected to different positions on the grounding member.

[0105] (Technical Concept 10) A power conversion device according to Technical Concept 9, comprising a cooler (22) having a refrigerant flow path (23) for cooling the inverter, wherein the noise filter has a P-side grounding portion (46P) electrically connected to the P-side grounding busbar and connected to the grounding member, and an N-side grounding portion (46N) electrically connected to the N-side grounding busbar and connected to the grounding member, wherein the distance from the P-side grounding portion to the refrigerant flow path is shorter than the distance from the first P-busbar to the refrigerant flow path, and the distance from the N-side grounding portion to the refrigerant flow path is shorter than the distance from the first N-busbar to the refrigerant flow path.

[0106] (Technical Concept 11) The power conversion device according to Technical Concept 9, comprising a cooler (22) having a refrigerant flow path (23) for cooling the inverter, wherein the distance from the P-side condenser to the refrigerant flow path is shorter than the distance from the first P busbar to the refrigerant flow path, and the distance from the N-side condenser to the refrigerant flow path is shorter than the distance from the first N busbar to the refrigerant flow path.

Claims

1. A first P busbar (41P) which is an input line on the high potential side; a first N busbar (41N) which is an input line on the low potential side; a second P busbar (42P) which branches off from the first P busbar and is arranged to extend along a predetermined direction; a second N busbar (42N) which branches off from the first N busbar and is arranged alongside the second P busbar and extends along the predetermined direction; a third P busbar (43P) which is connected to the second P busbar and is arranged to extend on the opposite side of the second N busbar to the second P busbar; a third N busbar (43N) which is connected to the second N busbar and is arranged to extend on the opposite side of the second P busbar to the second N busbar; a P-side capacitor (60P) with one end connected to the third P busbar to remove electromagnetic noise; and an N-side capacitor (60N) with one end connected to the third N busbar to remove electromagnetic noise. A noise filter comprising a P-side ground busbar (44P) connected to a grounding member (21) that provides a ground potential, to which the other end of the P-side capacitor is connected, and an N-side ground busbar (44N) connected to the other end of the N-side capacitor is connected to the grounding member, wherein the P-side ground busbar and the N-side ground busbar are connected to different positions on the grounding member.

2. The noise filter according to claim 1, wherein a plurality of the third P busbar, the third N busbar, the P-side ground busbar, the N-side ground busbar, the P-side capacitor, and the N-side capacitor are provided, at least one of the plurality of P-side capacitors has a different capacitance from the other P-side capacitors, and at least one of the plurality of N-side capacitors has a different capacitance from the other N-side capacitors.

3. A noise filter according to claim 2, comprising: a P-side connecting section (45P) that connects a plurality of P-side ground busbars and has a P-side ground section (46P) connected to the ground member; and an N-side connecting section (45N) that connects a plurality of N-side ground busbars and has an N-side ground section (46N) connected to the ground member.

4. The noise filter according to claim 3, wherein, among the plurality of P-side capacitors, the P-side capacitor with the largest capacitance is designated as the maximum P-side capacitor (62P), among the plurality of N-side capacitors, the N-side capacitor with the largest capacitance is designated as the maximum N-side capacitor (62N), the distance from the maximum P-side capacitor to the P-side ground is shorter than the distance from the other P-side capacitors to the P-side ground, and the distance from the maximum N-side capacitor to the N-side ground is shorter than the distance from the other N-side capacitors to the N-side ground.

5. A noise filter according to any one of claims 2 to 4, wherein the P-side capacitor with the smallest capacitance among the plurality of P-side capacitors is designated as the minimum P-side capacitor (61P), the N-side capacitor with the smallest capacitance among the plurality of N-side capacitors is designated as the minimum N-side capacitor (61N), the distance from the minimum P-side capacitor to the first P-busbar is shorter than the distance from the other P-side capacitors to the first P-busbar, and the distance from the minimum N-side capacitor to the first N-busbar is shorter than the distance from the other N-side capacitors to the first N-busbar.

6. The noise filter according to any one of claims 2 to 4, wherein the third P busbar is thinner than the second P busbar, and the third N busbar is thinner than the second N busbar.

7. The noise filter according to any one of claims 1 to 4, wherein the second P busbar is thinner than the first P busbar, and the second N busbar is thinner than the first N busbar.

8. The noise filter according to any one of claims 1 to 4, wherein the thickness of the first P busbar, the second P busbar, and the third P busbar are equal, and the thickness of the first N busbar, the second N busbar, and the third N busbar are equal.

9. A power conversion device comprising an inverter (6) that converts power by switching operation, and a noise filter (30), wherein the noise filter includes: a first P busbar (41P) which is a high-potential input line; a first N busbar (41N) which is a low-potential input line; a second P busbar (42P) which branches off from the first P busbar and is arranged to extend along a predetermined direction; a second N busbar (42N) which branches off from the first N busbar and is arranged alongside the second P busbar and extends along the predetermined direction; a third P busbar (43P) which is connected to the second P busbar and is arranged to extend on the opposite side of the second N busbar to the second N busbar; and a P-side capacitor (60P) which has one end connected to the third P busbar to remove electromagnetic noise. A power converter comprising: an N-side capacitor (60N) with one end connected to the third N busbar to remove electromagnetic noise; a P-side ground busbar (44P) to which the other end of the P-side capacitor is connected to a grounding member (21) that provides a ground potential; and an N-side ground busbar (44N) to which the other end of the N-side capacitor is connected to the grounding member, wherein the P-side ground busbar and the N-side ground busbar are connected to different positions on the grounding member.

10. The power conversion device according to claim 9, comprising a cooler (22) having a refrigerant flow path (23) for cooling the inverter, wherein the noise filter has a P-side grounding portion (46P) electrically connected to the P-side grounding busbar and connected to the grounding member, and an N-side grounding portion (46N) electrically connected to the N-side grounding busbar and connected to the grounding member, wherein the distance from the P-side grounding portion to the refrigerant flow path is shorter than the distance from the first P-busbar to the refrigerant flow path, and the distance from the N-side grounding portion to the refrigerant flow path is shorter than the distance from the first N-busbar to the refrigerant flow path.

11. The power conversion device according to claim 9, comprising a cooler (22) having a refrigerant flow path (23) for cooling the inverter, wherein the distance from the P-side condenser to the refrigerant flow path is shorter than the distance from the first P busbar to the refrigerant flow path, and the distance from the N-side condenser to the refrigerant flow path is shorter than the distance from the first N busbar to the refrigerant flow path.

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