Noise filter, power control unit, vehicular drive device, vehicular drive system, and noise filter core

Abstract

The present invention provides a noise filter that can be made more compact. The noise filter comprises a core with a through hole. The noise filter comprises at least one conductive member passing through the through hole. The core comprises a plurality of magnetic sheets stacked along the axial direction of the through hole.

Description

Noise filter, power control unit, vehicle drive device, vehicle drive system, and noise filter core

[0001] This application claims priority to Japanese Patent Application No. 2024-110411, filed on July 9, 2024, the entire contents of which are incorporated herein by reference. The technology disclosed in this specification relates to noise filters and the like.

[0002] Japanese Patent Publication No. 2020-519222 discloses a noise filter including a bus bar that is a conductive member and an annular core that surrounds the periphery of the bus bar.

[0003] When the distance between the busbar and the core is reduced to make the noise filter more compact, the eddy currents flowing through the core increase. Eddy current loss reduces the permeability, which in turn reduces the inductance. As a result, it is difficult to make the core more compact.

[0004] The present specification discloses a noise filter including a core having a through hole, at least one conductive member passing through the through hole, and a plurality of magnetic sheets stacked along the axial direction of the through hole.

[0005] In the above configuration, the multiple magnetic sheets can increase the axial electrical resistance of the core, thereby reducing eddy currents flowing in the axial direction. This can also prevent a decrease in inductance, allowing for a more compact core.

[0006] 3 is a diagram showing a schematic configuration of a vehicle 1. FIG. 4 is a diagram showing specific configurations of a first drive unit 20 and a second drive unit 40. FIG. 5 is a perspective view of a first filter 28. FIG. 6 is a cross-sectional view taken along line IV-IV in FIG. 3. FIG. 7 is a cross-sectional view taken along line V-V in FIG. 3. FIG. 8 is a cross-sectional view of a third filter 29. FIG. 9 is a cross-sectional view illustrating a filter 128 of a comparative example. FIG. 10 is a top view of a first filter 228 of Example 2. FIG. 11 is a top view of a first filter 328 according to a modified example of Example 2.

[0007] The at least one conductive member may include a plurality of conductive members.

[0008] According to the above configuration, when common mode noise occurs in a plurality of conductive members, the common mode noise can be removed.

[0009] Each of the plurality of conductive members may have a plate shape, and the plurality of conductive members may be arranged in the through hole in a thickness direction of the plate shape.

[0010] Compared to arranging multiple conductive members in the width direction of the plate shape, arranging multiple conductive members in the thickness direction of the plate shape allows the width of the through hole to be smaller, thereby making it possible to reduce the width of the core.

[0011] Each of the plurality of magnetic sheets may be made of a nanocrystalline magnetic material.

[0012] According to the above-described configuration, the core can be made even more highly permeable, and the noise filter can be made even more compact.

[0013] The thickness of each of the plurality of magnetic sheets may be 30 micrometers or less.

[0014] According to the above configuration, by reducing the thickness of the magnetic sheet, the magnetic permeability in the high frequency band can be improved, and the noise reduction effect in the high frequency range can be enhanced.

[0015] The conductive member or the insulator integrally provided on the conductive member may have an edge or a surface that faces the end face of the core in the axial direction.

[0016] According to the above configuration, the core can be positioned by the edge or the surface.

[0017] A power control unit according to an embodiment of the present invention may include the noise filter and a power converter. The power converter may be electrically connected to an external device via a conductive member. The power converter may include at least one switching element.

[0018] According to the above configuration, the noise filter can prevent noise generated from the switching element from propagating to an external device.

[0019] At least one switching element may be a compound semiconductor device.

[0020] When compound semiconductor devices are used to increase the speed and frequency of switching elements, electromagnetic noise may increase in the high-frequency range. With the above configuration, the electromagnetic noise in the high-frequency range can be removed by the noise filter.

[0021] One aspect of the vehicle drive device disclosed in this specification may include the above-mentioned power control unit and an electric motor electrically connected to the power control unit and driving wheels with power supplied from the power control unit. A casing of the power control unit may be directly fixed to a casing of the electric motor.

[0022] When the casing of the power control unit and the casing of the electric motor are directly fixed together, the size can be reduced, but electromagnetic noise may increase. With the above configuration, the increase in electromagnetic noise can be effectively suppressed by the noise filter.

[0023] One aspect of the vehicle drive system disclosed in this specification may include a first vehicle drive device that drives at least one first wheel, and a second vehicle drive device that drives at least one second wheel and is electrically connected to the first vehicle drive device. Each of the first vehicle drive device and the second vehicle drive device may be the vehicle drive device described above. A noise filter of the first vehicle drive device may be electrically interposed between a power conversion device of the first vehicle drive device and a power conversion device of the second vehicle drive device. A noise filter of the second vehicle drive device may be electrically interposed between a power conversion device of the second vehicle drive device and a power conversion device of the first vehicle drive device.

[0024] According to the above configuration, the noise filter of the first vehicle drive device and the noise filter of the second vehicle drive device can suppress resonance between the first vehicle drive device and the second vehicle drive device, making it possible to prevent noise generation due to resonance.

[0025] A core for a noise filter according to one aspect of the present invention includes a through hole configured to allow at least one conductive member to pass through, and the core includes a plurality of magnetic sheets stacked along the axial direction of the through hole.

[0026] According to the above configuration, the plurality of magnetic sheets can increase the electrical resistance of the core in the axial direction, and reduce eddy current loss, thereby making it possible to suppress a decrease in inductance.

[0027] (General Configuration of Vehicle 1) A vehicle 1 according to one embodiment will be described with reference to the general configuration diagram of Fig. 1 . The vehicle 1 is an electric vehicle. The vehicle 1 mainly includes a vehicle body 10, a pair of front wheels 11, a pair of rear wheels 12, a battery 15, an ECU 16, and a drive system 18. The drive system 18 includes a first drive unit 20 and a second drive unit 40. The first drive unit 20 is a unit that drives the front wheels 11. The second drive unit 40 is a unit that drives the rear wheels 12.

[0028] The first drive device 20 includes a first power control unit 21, a first electric motor 22, and a first gear unit 23. The first electric motor 22 is mechanically connected to the front wheels 11 via the first gear unit 23. The first electric motor 22 drives the front wheels 11 using power supplied from the first power control unit 21.

[0029] The first power control unit 21 is housed in a casing 21a. The first electric motor 22 is housed in a casing 22a. The first gear unit 23 is housed in a casing 23a. The casings 21a, 22a, and 23a are directly fixed to one another. This allows the first drive device 20 to be configured as an integrated unit, thereby making it possible to reduce the size of the device. Note that the direct fixing mode also includes a mode in which the casings are fixed via other components such as spacers. The direct fixing mode also includes a mode in which the casings are integrally formed. Furthermore, at least two of the casings 21a, 22a, and 23a may be directly fixed to one another.

[0030] Making the first drive device 20 an integrated unit may increase the amount of electromagnetic noise generated by the first drive device 20. However, the first drive device 20 is equipped with a first filter 28 and a third filter 29, which will be described later, and therefore can effectively suppress the radiation of electromagnetic noise.

[0031] The second drive device 40 includes a second power control unit 41, a second electric motor 42, and a second gear unit 43. The second electric motor 42 is mechanically connected to the rear wheel 12 via the second gear unit 43. The second electric motor 42 drives the rear wheel 12 using power supplied from the second power control unit 41. The second power control unit 41 is housed in a casing 41a. The second electric motor 42 is housed in a casing 42a. The second gear unit 43 is housed in a casing 43a. The casings 41a, 42a, and 43a are directly fixed to one another. This allows the second drive device 40 to be configured as an integrated unit, thereby making it possible to reduce the size of the device.

[0032] Battery 15 is a rechargeable battery that includes, but is not limited to, a plurality of lithium-ion cells. Battery 15 is electrically connected to connection nodes N1 and N2 via conductive members 71 and 72. Connection node N1 is connected to first power control unit 21 via conductive member 31 and to second power control unit 41 via conductive member 51. Similarly, connection node N2 is connected to first power control unit 21 via conductive member 32 and to second power control unit 41 via conductive member 52.

[0033] The ECU 16 controls the operations of the first power control unit 21 and the second power control unit 41 .

[0034] (Configuration of the first driving device 20 and the second driving device 40) Fig. 2 shows the specific configuration of the first driving device 20 and the second driving device 40. Note that in Fig. 2, the first gear unit 23 and the second gear unit 43 are omitted.

[0035] The configuration of the first drive device 20 will be described. The first drive device 20 includes a first power control unit 21 and a first electric motor 22. The first power control unit 21 includes a first inverter 26, a first DC-DC converter 27, a first filter 28, and a third filter 29. The first electric motor 22 is a three-phase motor generator having a U-phase, a V-phase, and a W-phase.

[0036] The first DC-DC converter 27 is a power conversion device capable of stepping up and down voltage. As an example, the first DC-DC converter 27 includes an inductor L1, an upper-arm switching element Q13, a lower-arm switching element Q14, an upper-arm diode D13, and a lower-arm diode D14. The inductor L1 is connected to the high-potential end of the battery 15 via conductive members 31 and 71. The emitter terminal of the lower-arm switching element Q14 is connected to the low-potential end of the battery 15 via conductive members 32 and 72. The first core 61 is disposed to surround the conductive members 31 and 32. The conductive members 31 and 32 and the first core 61 form a first filter 28. The first filter 28 is configured to remove common-mode noise generated in the conductive members 31 and 32.

[0037] The first inverter 26 is a power conversion device that converts DC power from the first DC-DC converter 27 into AC power. The first inverter 26 has a plurality of switching elements Q1 to Q6 and a plurality of diodes D1 to D6. Each of the plurality of diodes D1 to D6 is connected in parallel to a corresponding one of the plurality of switching elements Q1 to Q6. The plurality of switching elements Q1 to Q6 are selectively turned on and off by the ECU 16. The plurality of switching elements Q1 to Q6 are compound semiconductor devices. Compound semiconductor devices are elements fabricated using a substrate of a compound semiconductor (e.g., SiC, GaN). By using compound semiconductor devices, it is possible to achieve higher speeds and higher frequencies for the switching elements Q1 to Q6 compared to devices fabricated using a silicon substrate.

[0038] Each of the midpoints 26u, 26v, and 26w is electrically connected to the first electric motor 22 via the conductive members 33, 34, and 35. The third core 63 is disposed so as to surround the conductive members 33, 34, and 35. The conductive members 33, 34, and 35 and the third core 63 form a third filter 29. The third filter 29 is configured to be able to remove common mode noise generated in the conductive members 33, 34, and 35.

[0039] The configuration of the second drive device 40 will be described. The second drive device 40 includes a second power control unit 41 and a second electric motor 42. The second power control unit 41 includes a second inverter 46, a second DC-DC converter 47, a second filter 48, and a fourth filter 49. The second electric motor 42 is a three-phase motor generator.

[0040] The second DC-DC converter 47 has an inductor L2, an upper-arm switching element Q15, a lower-arm switching element Q16, an upper-arm diode D15, and a lower-arm diode D16. The inductor L2 is connected to the high-potential end of the battery 15 via conductive members 51 and 71. The emitter terminal of the lower-arm switching element Q16 is connected to the low-potential end of the battery 15 via conductive members 52 and 72. The second core 62 is disposed to surround the conductive members 51 and 52. The conductive members 51 and 52 and the second core 62 form a second filter 48.

[0041] The second inverter 46 has a plurality of switching elements Q7 to Q12 and a plurality of diodes D7 to D12. The midpoints 46u, 46v, and 46w are electrically connected to the second electric motor 42 via conductive members 53, 54, and 55, respectively. The fourth core 64 is disposed so as to surround the conductive members 53, 54, and 55. The conductive members 53, 54, and 55 and the fourth core 64 form a fourth filter 49.

[0042] The specific details of the second driving device 40 are the same as those of the first driving device 20. Therefore, a detailed description of the second driving device 40 will be omitted.

[0043] The first power control unit 21 and the second power control unit 41 are electrically connected to each other by conductive members 31 and 51 (high-potential side wiring) and conductive members 32 and 52 (low-potential side wiring). A first filter 28 and a second filter 48 are electrically interposed between the first power control unit 21 and the second power control unit 41. The first filter 28 and the second filter 48 can suppress resonance between the first power control unit 21 and the second power control unit 41, making it possible to prevent noise generation due to resonance.

[0044] (Specific Configurations of First Filter 28 and Second Filter 48) Fig. 3 shows a perspective view of first filter 28. Fig. 4 shows a cross-sectional view taken along line IV-IV in Fig. 3. Fig. 5 shows a cross-sectional view taken along line V-V in Fig. 3. First filter 28 includes a first core 61 and conductive members 31 and 32.

[0045] The first core 61 has a through hole 61h. The through hole 61h has a central axis CA. In this specification, the axial direction of the central axis CA is defined as the x-direction. The first core 61 has a plurality of magnetic sheets 61s stacked along the axial direction (x-direction) of the through hole 61h. That is, the stacking direction LD1 of the plurality of magnetic sheets 61s is the axial direction (x-direction). Each of the plurality of magnetic sheets 61s has a ring shape centered on the central axis CA.

[0046] The magnetic sheet 61s may be made of a variety of materials. For example, nanocrystalline magnetic materials, electromagnetic steel sheets (e.g., 6.5Si-Fe materials), pure iron-based materials, etc., can be used. In this embodiment, the magnetic sheet 61s is made of a nanocrystalline magnetic material. A nanocrystalline magnetic material is a soft magnetic material with a structure in which nano-sized crystals are contained in an amorphous alloy. By using a nanocrystalline magnetic material, the first core 61 can have even higher magnetic permeability than when electromagnetic steel sheets or the like are used. This allows the first filter 28 to be made smaller.

[0047] As shown in FIG. 5 , each of the multiple magnetic sheets 61s has a thickness T in the axial direction. The smaller the value of the thickness T, the more eddy current loss can be reduced. Therefore, the smaller the thickness T, the more effective it is at reducing noise in the high frequency range. The thickness T is preferably 30 micrometers or less. If the material of the magnetic sheets 61s is a nanocrystalline magnetic material, the thickness T is more preferably 5 micrometers or less. Furthermore, if the material of the magnetic sheets 61s is an electromagnetic steel plate, the thickness T is more preferably 1 micrometer or less. Furthermore, if the material of the magnetic sheets 61s is a pure iron-based material, the thickness T is more preferably 0.5 micrometers or less.

[0048] The conductive members 31 and 32 extend in the axial direction and pass through the through hole 61h. A current flows through the conductive members 31 and 32 in the x-direction. The conductive members 31 and 32 are fixed to the first core 61 while being insulated from each other. Various methods may be used to fix the conductive members 31 and 32 to the first core 61. For example, they may be fixed using a resin case (not shown), or they may be fixed by adhesive. Furthermore, various methods may be used to insulate the conductive members 31 and 32 from the first core 61. For example, they may be insulated by a resin case, or they may be insulated by sandwiching insulating paper between them.

[0049] The conductive members 31 and 32 may have various shapes. In this embodiment, the conductive members 31 and 32 have a plate shape. That is, as shown in Figure 4, the cross section perpendicular to the direction in which the conductive members 31 and 32 extend is rectangular.

[0050] The conductive members 31 and 32 may be arranged in various ways within the through hole 61h. In this embodiment, the conductive members 31 and 32 are arranged in the thickness direction (z direction) of the plate shape. Compared to when the conductive members 31 and 32 are arranged in the width direction (y direction) of the plate shape, when the conductive members 31 and 32 are arranged in the thickness direction (z direction) of the plate shape, the width W of the through hole 61h can be made smaller. Therefore, it is possible to reduce the size of the first core 61 in the width direction.

[0051] The conductive members 31 and 32 may be made of various materials, but in this example, the conductive members 31 and 32 are made of copper.

[0052] The specific configuration of the second filter 48 is similar to the specific configuration of the first filter 28 described above, and therefore a detailed description thereof will be omitted.

[0053] (Specific Configurations of Third Filter 29 and Fourth Filter 49) FIG. 6 shows a cross-sectional view of the third filter 29. FIG. 6 is a cross-sectional view similar to FIG. 5. The third filter 29 includes a third core 63 and conductive members 33, 34, and 35. The third core 63 includes a through hole 63h. The through hole 63h has a central axis CA. The third core 63 includes a plurality of magnetic sheets 63s stacked along the axial direction (x direction) of the through hole 63h. Each of the plurality of magnetic sheets 63s has a thickness T in the axial direction. Note that the specific details of the third core 63 are the same as those of the first core 61 described above, and therefore a detailed description thereof will be omitted.

[0054] The conductive members 33, 34, and 35 have a plate shape and are arranged in the thickness direction (z direction) of the plate shape. Note that the specific details of the conductive members 33, 34, and 35 are the same as the specific details of the conductive members 31 and 32 described above, and therefore detailed description thereof will be omitted.

[0055] The specific configuration of the fourth filter 49 is similar to that of the third filter 29 described above, and therefore a detailed description thereof will be omitted.

[0056] (Effects) First, a comparative filter 128 will be described using FIG. 7 . FIG. 7 is a cross-sectional view similar to FIG. 5 . The comparative filter 128 includes a core 161. The core 161 includes a continuous magnetic sheet 161s wound around a central axis CA. That is, the stacking direction LD0 of the magnetic sheet 161s is perpendicular to the central axis CA. When current flows through the conductive members 31 and 32, eddy currents are generated in the core 161. The current density of the eddy currents is maximized at the inner circumferential surface 161i of the through hole 161h due to the skin effect. In the comparative core 161, the magnetic sheet 161s is continuously arranged in the axial direction (x direction) on the inner circumferential surface 161i. Therefore, the electrical resistance of the core 161 is smaller in the axial direction (x direction) than in the direction perpendicular to the axial direction. As a result, the eddy current EC0 flowing in the axial direction increases, resulting in increased eddy current loss. The eddy current loss reduces the magnetic permeability, which reduces the common-mode inductance, making it difficult to reduce the size of the core 161.

[0057] On the other hand, in the first filter 28 of this embodiment, as shown in FIG. 5, the magnetic sheets 61s are stacked in the axial direction (x direction). As a result, the current path in the axial direction (x direction) is divided into multiple parts by the lamination interfaces. Therefore, the electrical resistance of the first core 61 is greater in the axial direction (x direction) than in the direction perpendicular to the axial direction. As a result, the eddy current EC1 flowing in the axial direction can be made smaller than the eddy current EC0 in the comparative example. Since eddy current loss can be reduced, the decrease in common-mode inductance can be suppressed. This allows the core to be made smaller.

[0058] As the frequency of the current flowing through the conductive members 31 and 32 increases, the skin effect increases, resulting in a higher eddy current density on the inner circumferential surface. Therefore, common-mode inductance decreases as the frequency increases, making it difficult to ensure filter performance. Meanwhile, recent power conversion devices have become increasingly sensitive to higher frequencies and faster switching speeds, resulting in increased noise in the high-frequency band. Therefore, filter cores are required to have improved common-mode inductance in the high-frequency band. As described above, the first core 61 of this embodiment can increase the electrical resistance in the axial direction (x-direction) on the inner circumferential surface 61i. This effectively suppresses the increase in eddy current EC1 in the high-frequency band. Therefore, it is possible to improve common-mode inductance in the high-frequency band.

[0059] In Example 2, the configuration of the first filter is different from that of Example 1. Components common to Examples 1 and 2 are denoted by the same reference numerals, and descriptions thereof will be omitted. Fig. 8 shows a top view of a first filter 228 of Example 2. The first filter 228 mainly includes first cores 61_1 and 61_2, conductive members 31 and 32, a resin case 65, and a Y capacitor substrate 66.

[0060] The first cores 61_1 and 61_2 have the same structure as the first core 61 of the first embodiment. The resin case 65 is an insulator integrally provided with the conductive members 31 and 32. The resin case 65 is a member that fixes the conductive members 31 and 32 and the first cores 61_1 and 61_2 in a mutually insulated state. The resin case 65 has a center portion 65c and end portions 65e1 and 65e2. The end portion 65e1 passes through the through hole 61_1h of the first core 61_1. The end portion 65e2 passes through the through hole 61_2h of the first core 61_2.

[0061] In the region between the first cores 61_1 and 61_2, an extended conductive portion 31o protrudes from the conductive member 31, and an extended conductive portion 32o protrudes from the conductive member 32. The extended conductive portions 31o and 32o are electrically connected to a Y capacitor substrate 66. A Y capacitor for removing common mode noise is disposed on the Y capacitor substrate 66.

[0062] A bent conductive portion 31e1 is connected to the end of the conductive member 31 in the −x direction, and a bent conductive portion 31e2 is connected to the end of the conductive member 31 in the +x direction. The bent conductive portions 31e1 and 31e2 protrude in the −y direction from the conductive member 31. The bent conductive portions 31e1 and 31e2 may be connected by various methods, such as welding.

[0063] An opposing surface 65s1 is formed at the boundary between the central portion 65c and the end portion 65e1. The opposing surface 65s1 faces the end surface 61_1s on the +x-direction side of the first core 61_1 in the axial direction (x-direction). The opposing surface 65s1 contacts the end surface 61_1s, thereby enabling the first core 61_1 to be positioned in the x-direction. Similarly, an opposing surface 65s2 is formed at the boundary between the central portion 65c and the end portion 65e2. The opposing surface 65s2 faces the end surface 61_2s on the −x-direction side of the first core 61_2 in the axial direction. The opposing surface 65s2 contacts the end surface 61_2s, thereby enabling the first core 61_2 to be positioned in the x-direction.

[0064] The second filter 48, the third filter 29, and the fourth filter 49 described in the first embodiment may also have the configuration described in the second embodiment.

[0065] (Modification of Example 2) Fig. 9 shows a first filter 328 according to a modification of Example 2. Fig. 9 is a top view similar to Fig. 8. In the region between the first cores 61_1 and 61_2, an extended conductive portion 31o protrudes from the conductive member 31, and an extended conductive portion 32o protrudes from the conductive member 32.

[0066] The edge 31s in the -x direction of the extended conductive portion 31o faces an end face 61_1s on the +x direction side of the first core 61_1 in the axial direction. Also, the edge 31e1s in the +x direction of the bent conductive portion 31e1 faces an end face 61_1f on the -x direction side of the first core 61_1 in the axial direction. This allows the first core 61_1 to be positioned in the x direction.

[0067] Similarly, the +x-direction edge 32s of the extended conductive portion 32o faces the -x-direction end face 61_2s of the first core 61_2 in the axial direction. Also, the -x-direction edge 31e2s of the bent conductive portion 31e2 faces the +x-direction end face 61_2f of the first core 61_2 in the axial direction. This allows the first core 61_2 to be positioned in the x direction.

[0068] Although the embodiments have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings simultaneously achieves multiple objectives, and achieving one of these objectives itself has technical utility.

[0069] (Modification) The number of conductive members passing through the through hole of the core is not limited to a plurality of members, and may be one. In this case, a normal mode filter can be configured.

[0070] The shape of the conductive member is not limited to a plate shape, but may be, for example, a bar shape with a circular cross section.

[0071] The technology described in this specification is not limited to electric vehicles, but can also be applied to hybrid vehicles, plug-in hybrid vehicles, and other vehicles that use an electric motor for at least part of their travel, such as fuel cell vehicles.

[0072] The technology of this specification is not limited to vehicles, but can also be applied to various other applications such as home power control systems.

[0073] The wheels driven by the first electric motor 22 and the second electric motor 42 are not limited to a combination of the front and rear wheels, but may be a combination of the left and right wheels, for example.

[0074] The first inverter 26 and the first DC-DC converter 27 are an example of a power conversion device. The battery 15 and the first electric motor 22 are an example of an external device.

Claims

1. A noise filter comprising: a core having a through hole; and at least one conductive member passing through the through hole, wherein the core comprises a plurality of magnetic sheets stacked along the axial direction of the through hole.

2. The noise filter according to claim 1, wherein said at least one conductive member comprises a plurality of conductive members.

3. The noise filter according to claim 2, wherein each of the plurality of conductive members has a plate shape, and the plurality of conductive members are arranged in the thickness direction of the plate shape within the through hole.

4. A noise filter according to any one of claims 1 to 3, wherein each of the plurality of magnetic sheets is made of a nanocrystalline magnetic material.

5. A noise filter according to any one of claims 1 to 4, wherein the thickness of each of the plurality of magnetic sheets is 30 micrometers or less.

6. A noise filter according to any one of claims 1 to 5, wherein the conductive member or an insulator integrally formed with the conductive member has an edge or surface that faces the end face of the core in the axial direction.

7. A power control unit comprising: a noise filter according to any one of claims 1 to 6; and a power conversion device, wherein the power conversion device is electrically connected to an external device via the conductive member, and the power conversion device comprises at least one switching element.

8. The power control unit of claim 7, wherein said at least one switching element is a compound semiconductor device.

9. A vehicle drive device comprising: a power control unit according to claim 7 or 8; and an electric motor electrically connected to said power control unit and driving wheels with power supplied from said power control unit, wherein the casing of said power control unit is directly fixed to the casing of said electric motor.

10. A vehicle drive system comprising: a first vehicle drive device that drives at least one first wheel; and a second vehicle drive device that drives at least one second wheel and is electrically connected to the first vehicle drive device, wherein each of the first vehicle drive device and the second vehicle drive device is the vehicle drive device described in claim 9, and the noise filter of the first vehicle drive device is electrically interposed between the power conversion device of the first vehicle drive device and the power conversion device of the second vehicle drive device, and the noise filter of the second vehicle drive device is electrically interposed between the power conversion device of the second vehicle drive device and the power conversion device of the first vehicle drive device.

11. A core for a noise filter, comprising a through hole configured to allow at least one conductive member to pass therethrough, and a plurality of magnetic sheets laminated along the axial direction of the through hole.

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