Capacitor and power conversion device provided with same

Abstract

The capacitor includes: a first capacitor having a first electrode and a second electrode; and a second capacitor having a third electrode and a fourth electrode. The first bus bar has a first external connection terminal and is connected to the first electrode and the third electrode. The second bus bar has a second external connection terminal and is connected to the second electrode. The third bus bar has a third external connection terminal and is connected to the fourth electrode. The housing accommodates the first capacitor, the second capacitor, the first bus bar, the second bus bar, and the third bus bar in a state in which at least a portion of each of the first external connection terminal, the second external connection terminal, and the third external connection terminal is exposed to the outside from the opening. The first electrode is connected to the first bus bar at a position closer to the first external connection terminal than the third electrode.

Description

Technical Field

[0001] The present disclosure relates to a capacitor and a power conversion device including the capacitor. More specifically, the present disclosure relates to a capacitor including a plurality of capacitor elements housed in a casing and a power conversion device including the capacitor. Background Art

[0002] Patent document 1 discloses a capacitor assembly in which a filter capacitor element for removing noise and a smoothing capacitor element for smoothing current are sealed with a sealing resin material. The capacitor assembly is used in a power conversion device having a converter unit and an inverter unit. The filter capacitor element is connected between a DC power supply and a converter unit. The smoothing capacitor element is provided on the input side of the inverter unit.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-22655 Summary of the invention

[0006] A capacitor of one embodiment of the present disclosure comprises: a first capacitor having a first electrode and a second electrode; a second capacitor having a third electrode and a fourth electrode; a first bus bar; a second bus bar; a third bus bar; and a housing. The first bus bar has a first external connection terminal connected to the first electrode and the third electrode. The second bus bar has a second external connection terminal connected to the second electrode. The third bus bar has a third external connection terminal connected to the fourth electrode. The housing accommodates the first capacitor, the second capacitor, the first bus bar, the second bus bar, and the third bus bar in a state where at least a portion of each of the first external connection terminal, the second external connection terminal, and the third external connection terminal is exposed to the outside from an opening. The first electrode is connected to the first bus bar at a position closer to the first external connection terminal than the third electrode.

[0007] A power conversion device according to one embodiment of the present disclosure includes the capacitor, a converter circuit, and an inverter circuit. The converter circuit performs voltage conversion of a DC voltage input from a DC power supply. The inverter circuit converts the output voltage of the converter circuit into an AC voltage. The first external connection terminal and the second external connection terminal are connected to an input portion of the inverter circuit. The first external connection terminal and the third external connection terminal are connected to a connection portion between the DC power supply and the converter circuit.

[0008] According to the present disclosure, the inductance between the external connection terminal and the first capacitor can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a perspective view of the appearance of a capacitor block included in the capacitor according to the embodiment of the present disclosure.

[0010] Figure 2 This is a perspective view of the appearance of a capacitor block included in the capacitor according to the embodiment of the present disclosure.

[0011] Figure 3 This is an external perspective view of a capacitor according to an embodiment of the present disclosure, with a power input terminal plate of a capacitor block removed.

[0012] Figure 4 It is a perspective view of the appearance of a capacitor according to an embodiment of the present disclosure.

[0013] Figure 5 It is an exploded perspective view of a capacitor according to an embodiment of the present disclosure.

[0014] Figure 6 This is a schematic circuit diagram of a power conversion device including a capacitor according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0015] In the capacitor assembly of Patent Document 1, if the inductance of the conductive path between the smoothing capacitor element connected to the input side of the inverter unit and the switching element increases, there is a possibility that an excessive voltage will be generated in the switching element. Therefore, it is desirable to reduce the inductance of the conductive path connecting the smoothing capacitor element (first capacitor) and the inverter unit.

[0016] The present disclosure provides a capacitor capable of reducing the inductance between an external connection terminal and a first capacitor, and a power conversion device including the capacitor.

[0017] The figures described in the following embodiments are schematic diagrams, and the size of each component and the ratio of the thickness are not necessarily limited to the actual size ratio. In addition, the structure described in the following embodiments is only an example of the present disclosure. The present disclosure is not limited to the following embodiments, and various changes can be made to the design, etc. as long as the effects of the present disclosure can be achieved.

[0018] (Implementation Method)

[0019] (1) Summary

[0020] Figure 1 This is a perspective view of the appearance of a capacitor block 100 included in the capacitor 1 according to the present embodiment, as viewed from the front. Figure 2 This is a perspective view of the capacitor block 100 as seen from the rear. Figure 3This is a perspective view of the appearance of the capacitor block 100 with a pair of power input terminal plates 60 and 70 removed. Figure 4 1 is a perspective view of the capacitor 1 in a state where the capacitor block 100 is housed in the case 200 and sealed with the sealing resin 300. Figure 5 2 is an exploded perspective view of the capacitor 1 before the capacitor block 100 is housed in the housing 200. Figure 1 to Figure 5 The X direction is defined as the left-right direction, the Y axis direction is defined as the front-back direction (depth direction), and the Z axis direction is defined as the up-down direction. Furthermore, the positive direction of the X axis direction is defined as the right side, the positive direction of the Y axis direction is defined as the front side, and the positive direction of the Z axis direction is defined as the upper side. However, these directions are examples and do not limit the directions of the capacitor 1 when in use. In addition, the arrows indicating the directions in the drawings are only marked for explanation and are not accompanied by entities.

[0021] The capacitor 1 of the present embodiment includes a first capacitor C1, a second capacitor C2, a first bus bar 30, a second bus bar 40, a third bus bar 50, and a housing 200. The first capacitor C1 has a first electrode E1 and a second electrode E2. The second capacitor C2 has a third electrode E3 and a fourth electrode E4. The first bus bar 30 has a first external connection terminal T1 connected to the first electrode E1 and the third electrode E3. The second bus bar 40 has a second external connection terminal T2 connected to the second electrode E2. The third bus bar 50 has a third external connection terminal T3 connected to the fourth electrode E4. The housing 200 accommodates the first capacitor C1, the second capacitor C2, the first bus bar 30, the second bus bar 40, and the third bus bar 50 in a state where at least a portion of each of the first external connection terminal T1, the second external connection terminal T2, and the third external connection terminal T3 is exposed to the outside from the opening 201 (see FIG. 2 ). Figure 4 That is, at least a portion of each of the first external connection terminal T1, the second external connection terminal T2, and the third external connection terminal T3 is exposed from the opening 201 to the outside of the housing 200. The first electrode E1 is connected to the first bus bar 30 at a position closer to the first external connection terminal T1 than the third electrode E3.

[0022] The capacitor 1 of the present embodiment is a composite capacitor including a first capacitor C1 and a second capacitor C2. In the present embodiment, the first electrode E1 of the first capacitor C1 is connected to the first bus bar 30 at a position closer to the first external connection terminal T1 than the third electrode E3 of the second capacitor C2. Therefore, the inductance of the conductive path between the first external connection terminal T1 and the first capacitor C1 can be reduced compared to the inductance of the conductive path between the first external connection terminal T1 and the second capacitor C2. For example, when the first capacitor C1 is connected to an inverter circuit as a switching power supply circuit, the inductance of the conductive path between the switching element of the inverter circuit and the first capacitor C1 can be reduced. As a result, in the capacitor 1 of the present embodiment, the voltage applied to the switching element when the switching element performs a switching action can be reduced, and the damage to the switching element can be reduced.

[0023] The capacitor 1 of this embodiment is used in a power conversion device 2 (refer to Figure 6 ). The power conversion device 2 converts the DC voltage input from the DC power supply 6 into, for example, a three-phase AC voltage, and supplies it to a load (for example, a three-phase AC motor 7). The power conversion device 2 includes the above-mentioned capacitor 1, the converter circuit 3, and the inverter circuit 4.

[0024] The converter circuit 3 performs voltage conversion of the DC voltage input from the DC power supply 6. The inverter circuit 4 converts the output voltage of the converter circuit 3 into an AC voltage. The first external connection terminal T1 and the second external connection terminal T2 are connected to the input portion of the inverter circuit 4. The first external connection terminal T1 and the third external connection terminal T3 are connected to the connection portion between the DC power supply 6 and the converter circuit 3. In addition, the power conversion device 2 is not limited to the one having Figure 6 The circuit configuration shown can be modified as appropriate. In addition, the use of the capacitor 1 is not limited to the power conversion device 2, and it can also be used in other applications.

[0025] (2) Structure

[0026] Below, reference Figure 1 to Figure 6The structure of the capacitor 1 involved in the present embodiment will be described in detail. As described above, the capacitor 1 includes a first capacitor C1, a second capacitor C2, a first bus bar 30, a second bus bar 40, a third bus bar 50, and a housing 200. The first bus bar 30 and the second bus bar 40 are connected to the first electrode E1 and the second electrode E2 of the first capacitor C1, respectively, and the first bus bar 30 and the third bus bar 50 are connected to the third electrode E3 and the fourth electrode E4 of the second capacitor C2, respectively, to form a capacitor block 100 in which the first capacitor C1 and the second capacitor C2 are integrated. The housing 200 accommodates the capacitor block 100. In addition, the capacitor 1 of the present embodiment further includes a pair of power input terminal plates 60, 70, and an insulating plate 80.

[0027] (2.1) First capacitor

[0028] The first capacitor C1 includes a plurality of first capacitor elements C11 connected in parallel. The plurality of first capacitor elements C11 are arranged along a second direction (e.g., an X-axis direction) intersecting a first direction (e.g., a Z-axis direction) in which the first capacitor C1 and the second capacitor C2 are arranged side by side. In the present embodiment, the first capacitor C1 includes, for example, seven first capacitor elements C11 connected in parallel. Each of the seven first capacitor elements C11 includes a main body 10, a first electrode E1, and a second electrode E2.

[0029] The main body 10 includes a material having dielectric properties. The material having dielectric properties is a dielectric or a material containing a dielectric. The dielectric is, for example, a resin such as polypropylene or polyethylene, or ceramics, but may also be air.

[0030] In this embodiment, the main body 10 is formed into a cylindrical shape by winding a dielectric film. The material of the dielectric film is, for example, polypropylene (biaxially oriented polypropylene, etc.), and can be PET (polyethylene terephthalate), PS (polystyrene), PEN (polyethylene naphthalate), etc. In this embodiment, as Figure 1 to Figure 3 As shown in the figure, the main body 10 is formed into a cylindrical shape (oblate cylindrical shape) with an oblate cross-sectional shape. In addition, the shape of the main body 10 is not limited to the oblate cylindrical shape, and may also be cylindrical, prism-shaped, or plate-shaped. In addition, the main body 10 may be formed, for example, by stacking dielectric sheets, or may be formed by sintering, injection molding, or the like.

[0031] A first electrode E1 is provided on one of two end surfaces (e.g., the rear end surface) of the main body 10 that are opposite to each other in the central axis direction, and a second electrode E2 is provided on the other end surface (e.g., the front end surface). Each of the first electrode E1 and the second electrode E2 is, for example, a vapor-deposited electrode formed by vapor-depositing a metal such as aluminum on the end surface of the main body 10.

[0032] The plurality of first capacitor elements C11 are each arranged inside the housing 200 so that the central axis of the main body 10 is parallel to the front-rear direction, the short side of the cross-sectional shape at a plane perpendicular to the central axis of the main body 10 is parallel to the up-down direction, and the long side of the cross-sectional shape of the main body 10 is parallel to the left-right direction. Here, the so-called "parallel" is not limited to a state where two directions are completely parallel, and may also include a state where they intersect at an angle of several degrees.

[0033] The first electrodes E1 of the plurality of first capacitor elements C11 are connected to the first bus bar 30, and the second electrodes E2 of the plurality of first capacitor elements C11 are connected to the second bus bar 40. That is, the plurality of first capacitor elements C11 are connected in parallel with each other. In addition, the first electrode E1 may be directly connected to the first bus bar 30, or may be electrically connected to the first bus bar 30 via other conductive members. Similarly, the second electrode E2 may be directly connected to the second bus bar 40, or may be electrically connected to the second bus bar 40 via other conductive members. In addition, the first electrodes E1 of the plurality of first capacitor elements C11 are connected to the first bus bar 30 at substantially the same position in the up-down direction. Similarly, the second electrodes E2 of the plurality of first capacitor elements C11 are connected to the second bus bar 40 at substantially the same position in the up-down direction.

[0034] In the capacitor 1 of the present embodiment, the first external connection terminal T1 of the first bus bar 30 and the second external connection terminal T2 of the second bus bar 40 are connected to the input portion of the inverter circuit 4. That is, the first capacitor C1 is connected to the input portion of the inverter circuit 4 and serves as a capacitor for stabilizing the input voltage of the inverter circuit 4.

[0035] (2.2) Second capacitor

[0036] The second capacitor C2 includes a plurality of second capacitor elements C21 connected in parallel. The plurality of second capacitor elements C21 are arranged along a second direction (e.g., an X-axis direction) intersecting a first direction (e.g., a Z-axis direction) in which the first capacitor C1 and the second capacitor C2 are arranged side by side. In the present embodiment, the second capacitor C2 includes, for example, two second capacitor elements C21 connected in parallel. The second capacitor element C21 includes a main body 20, a third electrode E3, and a fourth electrode E4.

[0037] The main body 20 includes a material having dielectric properties. The material having dielectric properties is a dielectric or a material containing a dielectric. The dielectric is, for example, a resin such as polypropylene or polyethylene, ceramics, or air.

[0038] In this embodiment, the main body 20 is formed into a cylindrical shape by winding a dielectric film. The material of the dielectric film is, for example, polypropylene, but may also be PET, PS, PEN, etc. In this embodiment, as shown in FIG. Figure 1 to Figure 3 As shown in the figure, the main body 20 is formed into a cylindrical shape (oblate cylindrical shape) with an oblate cross-sectional shape. In addition, the shape of the main body 20 is not limited to the oblate cylindrical shape, and may also be cylindrical, prism-shaped, or plate-shaped. In addition, the main body 20 may be formed, for example, by stacking dielectric sheets, or may be formed by sintering, injection molding, or the like.

[0039] A third electrode E3 is provided on one of the two end surfaces (e.g., the end surface on the rear side) of the main body 20 that are opposite to each other in the central axis direction, and a fourth electrode E4 is provided on the other end surface (e.g., the end surface on the front side). Each of the third electrode E3 and the fourth electrode E4 is, for example, a vapor-deposited electrode formed by vapor-depositing a metal such as aluminum on the end surface of the main body 10.

[0040] Multiple second capacitor elements C21 are each arranged inside the shell 200 so that the central axis of the main body 20 is parallel to the front-to-back direction, the short side of the cross-sectional shape at the surface perpendicular to the central axis of the main body 20 is parallel to the up-down direction, and the long side of the cross-sectional shape at the surface perpendicular to the central axis of the main body 20 is parallel to the left-right direction.

[0041] The third electrodes E3 of the plurality of second capacitor elements C21 are connected to the first bus bar 30, and the fourth electrodes E4 of the plurality of second capacitor elements C21 are connected to the third bus bar 50. That is, the plurality of second capacitor elements C21 are connected in parallel. In addition, the third electrode E3 may be directly connected to the first bus bar 30, or may be electrically connected to the first bus bar 30 via other conductive members. Similarly, the fourth electrode E4 may be directly connected to the third bus bar 50, or may be electrically connected to the third bus bar 50 via other conductive members. In addition, the third electrodes E3 of the plurality of second capacitor elements C21 are connected to the first bus bar 30 at substantially the same position in the up-down direction. Similarly, the fourth electrodes E4 of the plurality of second capacitor elements C21 are connected to the third bus bar 50 at substantially the same position in the up-down direction.

[0042] In the capacitor 1 of the present embodiment, the first external connection terminal T1 of the first bus bar 30 and the third external connection terminal T3 of the third bus bar 50 are connected to the connection portion between the DC power supply 6 and the converter circuit 3. That is, the second capacitor C2 is connected to the connection portion between the DC power supply 6 and the converter circuit 3 and functions as a capacitor for stabilizing the input voltage from the DC power supply 6.

[0043] As described above, in the capacitor 1 of the present embodiment, the second capacitor C2 is connected to the connection portion between the DC power supply 6 and the converter circuit 3, and the first capacitor C1 is connected to the input portion of the inverter circuit 4. For this reason, the electrostatic capacitance of the first capacitor C1 is larger than the electrostatic capacitance of the second capacitor C2. In the capacitor 1 of the present embodiment, the inductance between the first capacitor C1 and the first external connection terminal T1 is made smaller than the inductance between the second capacitor C2 and the first external connection terminal T1, so that the possibility of applying an excessive voltage to the switching element of the inverter circuit 4 connected to the first capacitor C1 having a larger capacitance than the second capacitor C2 can be reduced.

[0044] (2.3) Bus bar No. 1

[0045] The first bus bar 30 is formed by, for example, pressing a sheet metal such as copper or a copper alloy. Figure 2 As shown, the first bus bar 30 has a horizontal piece 31 arranged to contact the rear surfaces of the plurality of first capacitor elements C11 arranged side by side in the left-right direction. The horizontal piece 31 is substantially L-shaped when viewed from the left-right direction and is arranged to contact the upper surfaces and rear surfaces of the plurality of first capacitor elements C11.

[0046] A plurality of (e.g., seven) first external connection terminals T1 protruding upward are provided at appropriate positions on the upper side of the horizontal piece 31. Each of the plurality of first external connection terminals T1 is formed into a rectangular plate shape and arranged so that the thickness direction is parallel to the front-rear direction. In addition, the plurality of first external connection terminals T1 are arranged side by side in the left-right direction.

[0047] In addition, a plurality of (eg, seven) connection terminals 32 protrude downward from the lower side of the horizontal piece 31 and are soldered to the first electrodes E1 of the first capacitor elements C11. The connection terminals 32 may be directly connected to the first electrodes E1 or may be electrically connected to the first electrodes E1 via other conductive members.

[0048] Here, the portion where the connection terminal 32 is connected to the first electrode E1 becomes the connection portion between the first electrode E1 of the first capacitor C1 and the first bus bar 30. Since the first capacitor C1 is composed of a plurality of first capacitor elements C11, the connection portions between the plurality of first electrodes E1 and the first bus bar 30 of the first capacitor C1 become the plurality of portions where the plurality of first electrodes E1 and the plurality of connection terminals 32 are connected, respectively. Therefore, the first dimension A1 between the connection portion between the first electrode E1 and the first bus bar 30 and the first external connection terminal T1 becomes the shortest dimension between the plurality of first electrodes E1 of the plurality of first capacitor elements C11 and the first external connection terminal T1. In the present embodiment, since the plurality of first electrodes E1 are connected to the plurality of connection terminals 32 at substantially the same position in the up-down direction, the dimensions (first dimension A1) between the plurality of connection portions where the plurality of first electrodes E1 and the plurality of connection terminals 32 are respectively connected and the first external connection terminal T1 become substantially the same value.

[0049] In addition, two vertical pieces 33 protrude downward from the central part in the left-right direction of the horizontal piece 31. The two vertical pieces 33 are provided corresponding to the two second capacitor elements C21, respectively. The two vertical pieces 33 are each provided with a connection terminal 34 of the third electrode E3 of the corresponding second capacitor element C21 brazed to the two second capacitor elements C21. In addition, the connection terminal 34 can be directly connected to the third electrode E3, or can be electrically connected to the third electrode E3 via other conductive members.

[0050] Here, the portion where the connection terminal 34 is connected to the third electrode E3 becomes the connection portion between the third electrode E3 of the second capacitor C2 and the first bus bar 30. Since the second capacitor C2 is composed of a plurality of second capacitor elements C21, the connection portions between the plurality of third electrodes E3 of the second capacitor C2 and the first bus bar 30 become the plurality of portions where the plurality of third electrodes E3 are connected to the plurality of connection terminals 34, respectively. Therefore, the second dimension A2 between the connection portion between the third electrode E3 and the first bus bar 30 and the first external connection terminal T1 becomes the shortest dimension between the plurality of third electrodes E3 of the plurality of second capacitor elements C21 and the first external connection terminal T1. In the present embodiment, since the plurality of third electrodes E3 are connected to the plurality of connection terminals 34 at substantially the same position in the up-down direction, the dimensions (second dimension A2) between the plurality of connection portions where the plurality of third electrodes E3 are connected to the plurality of connection terminals 34, respectively, and the first external connection terminal T1 become substantially the same value.

[0051] As described above, the first bus bar 30 is connected to the plurality of first electrodes E1 of the first capacitor C1 and the plurality of third electrodes E3 of the second capacitor C2. In the power conversion device 2, the plurality of first electrodes E1 of the first capacitor C1 and the plurality of third electrodes E3 of the second capacitor C2 are connected to the ground of the circuit. In addition, the second electrode E2 of the first capacitor C1 is connected to the input terminal on the high voltage side of the inverter circuit 4, and the fourth electrode E4 of the second capacitor C2 is connected to the high voltage side of the DC power supply 6.

[0052] (2.4) Bus bar No. 2

[0053] The second bus bar 40 is formed by, for example, pressing a sheet metal such as copper or a copper alloy. Figure 1 The horizontal piece 41 is arranged to contact the front surfaces of the plurality of first capacitor elements C11 arranged in the horizontal direction. The horizontal piece 41 is substantially L-shaped when viewed from the horizontal direction and is arranged to contact the upper surfaces and front surfaces of the plurality of first capacitor elements C11.

[0054] On the upper side of the horizontal piece 41, a plurality of (for example, 7) second external connection terminals T2 protruding upward are provided at appropriate positions. The plurality of second external connection terminals T2 are each formed into a rectangular plate shape, and are arranged so that the thickness direction is parallel to the front-back direction. In addition, the plurality of second external connection terminals T2 are arranged side by side in the left-right direction. In addition, the plurality of second external connection terminals T2 are each arranged at a position that does not overlap with the plurality of first external connection terminals T1 when viewed from the front-back direction.

[0055] In addition, multiple (for example, 7) connection terminals 42 protrude downward from the lower side of the horizontal piece 41 and are soldered to the second electrodes E2 of the first capacitor elements C11. The connection terminals 42 may be directly connected to the second electrodes E2 or may be electrically connected to the second electrodes E2 via other conductive members.

[0056] (2.5) Bus bar No. 3

[0057] The third bus bar 50 is formed, for example, by pressing a sheet metal of copper or a copper alloy. The third bus bar 50 has a horizontal piece 51 arranged to be in contact with the front surfaces of two second capacitor elements C21 arranged side by side in the left-right direction. Two connection terminals 52 protrude downward from the lower side of the horizontal piece 51 and are respectively soldered to the fourth electrodes E4 of the two second capacitor elements C21.

[0058] In addition, the longitudinal piece 53 having an L-shaped shape when viewed from the left and right directions protrudes upward from the upper side of the transverse piece 51. The longitudinal piece 53 is arranged along the front surface and the upper surface of the first capacitor element C11. A gap is provided between the longitudinal piece 53 and the front surface and the upper surface of the first capacitor element C11 so as not to contact the front surface and the upper surface of the first capacitor element C11. In addition, the third external connection terminal T3 protrudes upward from the rear end portion of the portion of the longitudinal piece 53 located on the upper side of the first capacitor element C11. The third external connection terminal T3 is formed into a rectangular plate shape and is arranged so that the thickness direction is parallel to the front-to-back direction. In addition, the third external connection terminal T3 is arranged at a position that does not overlap with each of the plurality of first external connection terminals T1 and the plurality of second external connection terminals T2 when viewed from the front-to-back direction.

[0059] Furthermore, the third external connection terminal T3 is arranged so that the second external connection terminal T2 located in the center among the plurality of second external connection terminals T2 is located between the first external connection terminal T1 located in the center among the plurality of first external connection terminals T1 and the third external connection terminal T3. Figure 1 to Figure 6 The arrangement of the first external connection terminal T1 , the second external connection terminal T2 , and the third external connection terminal T3 shown is an example and can be changed as appropriate.

[0060] (2.6) Insulation board

[0061] The insulating plate 80 is formed of an insulating synthetic resin such as PS or PPS (polyphenylene sulfide) and has a rectangular plate-shaped horizontal plate portion 81 inserted between the two second capacitor elements C21 and the plurality of first capacitor elements C11 located above the two second capacitor elements C21 .

[0062] The front end of the horizontal plate portion 81 is provided with a strip-shaped flange portion 82 protruding upward and downward from the front end of the horizontal plate portion 81. In addition, the insulating plate 80 includes a vertical piece 83 protruding upward from the flange portion 82 and arranged between the third bus bar 50 and the first capacitor element C11.

[0063] In a state where the insulating plate 80 is disposed between the two second capacitor elements C21 and the plurality of first capacitor elements C11, the convex edge portion 82 of the insulating plate 80 is disposed in front of the second electrode E2 and the fourth electrode E4. In addition, the vertical piece 83 of the insulating plate 80 is disposed between the third bus bar 50 and the first capacitor element C11 and the second bus bar 40. Thus, the electrical insulation between the second electrode E2 of the first capacitor element C11 and the fourth electrode E4 of the second capacitor element C21 can be improved.

[0064] (2.7) Shell

[0065] The housing 200 is formed of an insulating synthetic resin such as PPS into a box shape having an opening 201 on the upper surface. The housing 200 contains a capacitor block 100, which includes a first capacitor C1 and a second capacitor C2, and a first bus bar 30, a second bus bar 40, and a third bus bar 50 connected to the first electrode E1 to the fourth electrode E4 of the first capacitor C1 and the second capacitor C2. In addition, an insulating plate 80 is installed between the first capacitor C1 and the second capacitor C2 in the capacitor block 100.

[0066] Inside the housing 200, the first capacitor C1 and the second capacitor C2 are housed side by side in one direction, and the first capacitor C1 is arranged between the second capacitor C2 and the opening 201. In the present embodiment, inside the housing 200, the first capacitor C1 and the second capacitor C2 are arranged in two layers in the vertical direction (one direction). In addition, the direction in which the first capacitor C1 and the second capacitor C2 are arranged side by side (the vertical direction) is the first direction, and the plurality of first capacitor elements C11 and the plurality of second capacitor elements C21 are arranged along the second direction (the horizontal direction) intersecting the first direction.

[0067] Thus, in the direction in which the first capacitor C1 and the second capacitor C2 are arranged side by side, the first dimension A1 between the connection point of the first electrode E1 and the first bus bar 30 and the first external connection terminal T1 is shorter than the second dimension A2 between the connection point of the third electrode E3 and the first bus bar 30 and the first external connection terminal T1. Here, the connection point of the first electrode E1 and the first bus bar 30 is a point in the first electrode E1 where the connection terminal 32 of the first bus bar 30 is connected directly or via another conductive member. In addition, the connection point of the third electrode E3 and the first bus bar 30 is a point in the third electrode E3 where the connection terminal 34 of the first bus bar 30 is connected directly or via another conductive member. Since the first capacitor C1 and the second capacitor C2 are arranged so that the first dimension A1 is shorter than the second dimension A2, the inductance between the first capacitor C1 and the first external connection terminal T1 can be made smaller than the inductance between the second capacitor C2 and the first external connection terminal T1. Therefore, when the first capacitor C1 is connected to the input portion of the inverter circuit 4, the inductance of the conductive path between the switching elements Q3 to Q8 of the inverter circuit 4 and the first capacitor C1 can be reduced. Therefore, in the capacitor 1 of the present embodiment, the voltage applied to the switching elements Q3 to Q8 when the switching elements Q3 to Q8 perform a switching operation can be reduced, and damage to the switching elements Q3 to Q8 can be reduced.

[0068] Here, inside the housing 200, the second capacitor C2 is arranged on the lower side, and the first capacitor C1 is arranged on the upper side. Since the electrostatic capacitance of the second capacitor C2 is smaller than the electrostatic capacitance of the first capacitor C1, the number of the second capacitor elements C21 constituting the second capacitor C2 can be made smaller than the number of the first capacitor elements C11 constituting the first capacitor C1. Therefore, since the width dimension of the second capacitor C2 in the left-right direction is smaller than the width dimension of the first capacitor C1 in the left-right direction, the lower part of the housing 200 is formed to a size that can accommodate the second capacitor C2, and therefore, the width dimension of the lower part of the housing 200 in the left-right direction becomes smaller than that of the upper part. Therefore, compared with the case where the left-right dimensions of the upper part and the lower part of the housing 200 are the same, the housing 200 can be miniaturized.

[0069] With the capacitor block 100 accommodated in the housing 200, a sealing resin 300 such as epoxy resin is filled inside the housing 200. The sealing resin 300 is cured to fix the capacitor block 100 inside the housing 200. In addition, with the capacitor block 100 accommodated in the housing 200 and the sealing resin 300 filled inside the housing 200, substantially all of the first external connection terminal T1, the second external connection terminal T2, and the third external connection terminal T3 are exposed from the surface of the sealing resin 300.

[0070] A terminal block 205 (see FIG. 2 ) having screw terminals 61 and 71 disposed at the ends of a pair of power input terminal blocks 60 and 70 is integrally provided on the front surface of the housing 200. Figure 4 ). Screw parts 63 and 73 on which terminal screws are installed are provided in the screw terminal parts 61 and 71 arranged on the terminal block 205. By clamping a conductive member such as an electric wire or a conductive strip between the screw terminal parts 61 and 71 and the terminal screws installed on the screw parts 63 and 73, the conductive member is connected to the power input terminal boards 60 and 70 respectively, and the power input terminal boards 60 and 70 are connected to the DC power supply 6 via the conductive member. In addition, a partition wall 206 arranged between the screw terminal parts 61 and 71 is provided on the terminal block 205.

[0071] In addition, a plurality of ribs 203 are provided on the outer surface of the housing 200. The ribs 203 are provided with through holes 202 for inserting screws for fixing the housing 200. Therefore, the housing 200 can be fixed to the fixing object using fastening members such as bolts passing through the through holes 202 of the ribs 203.

[0072] (2.8) Power input terminal board

[0073] The capacitor 1 further includes a pair of power input terminal plates 60 and 70 connected to the first external connection terminal T1 and the third external connection terminal T3 , respectively. The first external connection terminal T1 and the third external connection terminal T3 are connected to the DC power supply 6 via the pair of power input terminal plates 60 and 70 .

[0074] Of the pair of power input terminal boards 60 and 70 , the power input terminal board 60 is electrically connected to the positive electrode of the DC power supply 6 , and the power input terminal board 70 is electrically connected to the negative electrode of the DC power supply 6 .

[0075] The power input terminal board 70 is connected to the first external connection terminal T1 located in the center among the plurality of first external connection terminals T1. The power input terminal board 60 is connected to the third external connection terminal T3, and the third external connection terminal T3 is arranged adjacent to the second external connection terminal T2 located in the center among the plurality of second external connection terminals T2.

[0076] The power input terminal plates 60 and 70 are formed by pressing a plate of copper or copper alloy. As described above, the power input terminal plates 60 and 70 include the screw terminal portions 61 and 71 disposed on the terminal block 205 of the housing 200 .

[0077] The power input terminal board 60 has a screw terminal portion 61 at one end. In addition, the power input terminal board 60 has a terminal piece 62 arranged to overlap with the third external connection terminal T3 at the other end. In the power input terminal board 60, an intermediate portion 64 between the screw terminal portion 61 and the terminal piece 62 is arranged along the outer wall of the housing 200.

[0078] The power input terminal board 70 has a screw terminal portion 71 at one end. In addition, the power input terminal board 70 has a terminal piece 72 at the other end that is overlapped with the first external connection terminal T1 at the center among the seven first external connection terminals T1. In the power input terminal board 70, an intermediate portion 74 between the screw terminal portion 71 and the terminal piece 72 is arranged along the outer wall of the housing 200.

[0079] In the present embodiment, a pair of power input terminal plates 60, 70 are arranged outside the housing 200. It is not necessary for the capacitor 1 to have a pair of power input terminal plates 60, 70, and they can be omitted as appropriate. In addition, since the pair of power input terminal plates 60, 70 are arranged outside the housing 200, a pair of power input terminal plates 60, 70 can also be added to the capacitor 1.

[0080] (3) Assembly steps of capacitors

[0081] The capacitor 1 of the present embodiment is assembled, for example, by the following steps. The assembly steps described below are just examples and can be modified as appropriate.

[0082] First, the first electrodes E1 of the first capacitor elements C11 are connected to the connection terminals 32 of the first bus bar 30 by, for example, soldering, and the third electrodes E3 of the second capacitor elements C21 are connected to the connection terminals 34 of the first bus bar 30 by, for example, soldering.

[0083] Next, the lateral plate portion 81 of the insulating plate 80 is inserted between the plurality of second capacitor elements C21 and the plurality of first capacitor elements C11 .

[0084] Then, the second electrodes E2 of the plurality of first capacitor elements C11 are connected to the plurality of connection terminals 42 of the second bus bar 40 by, for example, soldering, and the fourth electrodes E4 of the plurality of second capacitor elements C21 are connected to the plurality of connection terminals 52 of the third bus bar 50 by, for example, soldering. Thus, a capacitor block 100 is formed in which the plurality of first capacitor elements C11 and the plurality of second capacitor elements C21 are integrated via the first bus bar 30, the second bus bar 40, and the third bus bar 50.

[0085] Furthermore, the first external connection terminal T1 located in the center among the plurality of first external connection terminals T1 is joined to the terminal piece 72 of the power input terminal board 70 by an appropriate method, and the third external connection terminal T3 is joined to the terminal piece 62 of the power input terminal board 60 by an appropriate method.

[0086] Next, the capacitor block 100 with the pair of power input terminal plates 60 and 70 mounted thereon is housed in the case 200 through the opening 201 , the case 200 is filled with the sealing resin 300 , and the sealing resin 300 is cured, thereby completing the assembly of the capacitor 1 .

[0087] At this time, since the first external connection terminal T1, the second external connection terminal T2, and the third external connection terminal T3 are exposed to the outside from the opening 201 of the housing 200, wiring can be connected to the first external connection terminal T1, the second external connection terminal T2, and the third external connection terminal T3.

[0088] Furthermore, since the screw terminal portions 61 , 71 of the pair of power input terminal blocks 60 , 70 are disposed on the terminal block 205 of the housing 200 , the conductive member from the DC power supply 6 can be connected to the screw terminal portions 61 , 71 .

[0089] (4) Power conversion device

[0090] The capacitor 1 of the present embodiment is used in a power conversion device 2 . Figure 6This is a schematic circuit diagram of the power conversion device 2. As described above, the power conversion device 2 includes a capacitor 1, a converter circuit 3, and an inverter circuit 4. In addition, the power conversion device 2 also includes a third capacitor C3 for noise removal called a Y capacitor, and a control circuit 5.

[0091] The second capacitor C2 is connected to the connection portion between the DC power source 6 and the converter circuit 3. Furthermore, the third capacitor C3 is connected in parallel with the DC power source 6 between the DC power source 6 and the second capacitor C2.

[0092] The converter circuit 3 is a boost converter including an inductor L1 and a pair of switching elements Q1 and Q2. The pair of switching elements Q1 and Q2 are, for example, semiconductor switching elements such as IGBT (Insulated Gate Bipolar Transistor) or MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). The switching operation of the pair of switching elements Q1 and Q2 is controlled by the control circuit 5, and the converter circuit 3 outputs a DC voltage of a given voltage value obtained by boosting the input voltage from the DC power supply 6.

[0093] The first capacitor C1 is connected to a connection portion between the converter circuit 3 and the inverter circuit 4. That is, the first capacitor C1 is connected to an input portion of the inverter circuit 4.

[0094] The inverter circuit 4 is a three-phase inverter circuit in which a series circuit of a pair of switching elements Q3 and Q4, a series circuit of a pair of switching elements Q5 and Q6, and a series circuit of a pair of switching elements Q7 and Q8 are connected in parallel between both ends of the first capacitor C1. For example, the connection point of the pair of switching elements Q3 and Q4 is connected to the U terminal of the three-phase AC motor 7, the connection point of the pair of switching elements Q5 and Q6 is connected to the V terminal of the three-phase AC motor 7, and the connection point of the pair of switching elements Q7 and Q8 is connected to the W terminal of the three-phase AC motor 7. The switching operation of the switching elements Q3 to Q8 is controlled by the control circuit 5, and the inverter circuit 4 converts the input voltage from the converter circuit 3 into a three-phase AC voltage and outputs it to the three-phase AC motor 7.

[0095] Thus, the power conversion device 2 converts the DC voltage from the DC power supply 6 into a three-phase AC voltage and outputs the voltage to the three-phase AC motor 7, thereby rotating the three-phase AC motor 7 at a desired rotation speed or rotation torque.

[0096] The power conversion device 2 of this embodiment is mounted on a car, for example, and is used to drive a three-phase AC motor 7 mounted on the car. In addition, the power conversion device 2 is not limited to being used in a car, and can also be used in a mobile body such as a train, a ship, and an aircraft. In addition, the power conversion device 2 can also be used as a power supply circuit of an electrical device installed in a facility, or a power supply circuit of a portable electrical device.

[0097] (5) Modification

[0098] The above embodiment is only one of various embodiments of the present disclosure. As long as the above embodiment can achieve the purpose of the present disclosure, various changes can be made to the design, etc. Below, the modified examples of the above embodiment are listed. The modified examples described below can be used in combination as appropriate.

[0099] In the above-described capacitor 1 , the first capacitor C1 is constituted by seven first capacitor elements C11 arranged in the left-right direction and connected in parallel to each other, but the number and arrangement of the first capacitor elements C11 constituting the first capacitor C1 can be changed as appropriate.

[0100] In the above capacitor 1, the second capacitor C2 is constituted by two second capacitor elements C21 arranged in the left-right direction and connected in parallel to each other, but the number and arrangement of the second capacitor elements C21 constituting the second capacitor C2 can be changed as appropriate.

[0101] In addition, in the above-mentioned capacitor 1 , a third capacitor C3 may be further accommodated in the case 200 .

[0102] (Summarize)

[0103] The following aspects are disclosed from the above-described embodiments and the like.

[0104] A capacitor (1) of the first embodiment comprises: a first capacitor (C1) having a first electrode (E1) and a second electrode (E2); a second capacitor (C2) having a third electrode (E3) and a fourth electrode (E4); a first bus bar (30); a second bus bar (40); a third bus bar (50); and a housing (200). The first bus bar (30) has a first external connection terminal (T1) connected to the first electrode (E1) and the third electrode (E3). The second bus bar (40) has a second external connection terminal (T2) connected to the second electrode (E2). The third bus bar (50) has a third external connection terminal (T3) connected to the fourth electrode (E4). The housing (200) accommodates a first capacitor (C1), a second capacitor (C2), a first bus bar (30), a second bus bar (40), and a third bus bar (50) in a state where at least a portion of each of a first external connection terminal (T1), a second external connection terminal (T2), and a third external connection terminal (T3) is exposed to the outside from an opening (201). The first electrode (E1) is connected to the first bus bar (30) at a position closer to the first external connection terminal (T1) than the third electrode (E3).

[0105] According to this embodiment, the inductance between the first external connection terminal (T1) and the first capacitor (C1) can be reduced compared to the inductance between the first external connection terminal (T1) and the second capacitor (C2). For example, when the first capacitor (C1) is connected to an inverter circuit as a switching power supply circuit, the inductance between the switching element provided in the inverter circuit and the first capacitor (C1) can be reduced, and the voltage applied to the switching element when performing a switching operation can be reduced.

[0106] In a capacitor (1) of a second embodiment, based on the first embodiment, a first capacitor (C1) and a second capacitor (C2) are housed side by side inside a housing (200) so that the first capacitor (C1) is arranged between the second capacitor (C2) and the opening (201).

[0107] According to this aspect, the inductance between the first external connection terminal (T1) and the first capacitor (C1) can be reduced compared to the inductance between the first external connection terminal (T1) and the second capacitor (C2).

[0108] In a capacitor (1) of the third embodiment, based on the second embodiment, in the first direction in which the first capacitor (C1) and the second capacitor (C2) are arranged side by side, a first dimension (A1) between a connection point where the first bus bar (30) is connected to the first electrode (E1) and a first external connection terminal (T1) is shorter than a second dimension (A2) between a connection point where the first bus bar (30) is connected to the third electrode (E3) and the first external connection terminal (T1).

[0109] According to this aspect, the inductance between the first external connection terminal (T1) and the first capacitor (C1) can be reduced compared to the inductance between the first external connection terminal (T1) and the second capacitor (C2).

[0110] A capacitor (1) according to a fourth embodiment is used in a power conversion device (2) having a converter circuit (3) and an inverter circuit (4) based on any one of the first to third embodiments. The converter circuit (3) performs voltage conversion of a DC voltage input from a DC power supply (6). The inverter circuit (4) converts the output voltage of the converter circuit (3) into an AC voltage. The first external connection terminal (T1) and the second external connection terminal (T2) are connected to an input portion of the inverter circuit (4). The first external connection terminal (T1) and the third external connection terminal (T3) are connected to a connection portion between the DC power supply (6) and the converter circuit (3).

[0111] According to this embodiment, the inductance between the first external connection terminal (T1) and the first capacitor (C1) can be reduced compared to the inductance between the first external connection terminal (T1) and the second capacitor (C2). Therefore, the inductance between the switching element of the inverter circuit (4) connected to the first capacitor (C1) and the first capacitor (C1) can be reduced, and the voltage applied to the switching element when performing a switching operation can be reduced.

[0112] The capacitor (1) of the fifth aspect is based on the fourth aspect, and further includes a pair of power input terminal plates (60, 70). The first external connection terminal (T1) is connected to the DC power supply (6) via one of the pair of power input terminal plates (60, 70). The third external connection terminal (T3) is connected to the DC power supply (6) via the other of the pair of power input terminal plates (60, 70).

[0113] According to this embodiment, a pair of power input terminal boards (60, 70) can be used to connect a DC power supply (6) to a power conversion device (2).

[0114] A capacitor (1) according to a sixth aspect is the capacitor according to the fifth aspect, wherein a pair of power input terminal plates (60, 70) are arranged outside a housing (200).

[0115] According to this method, it is also possible to easily handle the further sliding and addition of a pair of power input terminal plates (60, 70).

[0116] In a seventh aspect of the capacitor (1), in any one of the first to sixth aspects, the first capacitor (C1) includes a plurality of first capacitor elements (C11) connected in parallel. The plurality of first capacitor elements (C11) are arranged along a second direction intersecting with a first direction in which the first capacitor (C1) and the second capacitor (C2) are arranged side by side.

[0117] According to this aspect, the electrostatic capacitance of the first capacitor (C1) can be easily adjusted by the number of first capacitor elements (C11).

[0118] In the capacitor (1) of the eighth aspect, in any one of the first to seventh aspects, the second capacitor (C2) includes a plurality of second capacitor elements (C21) connected in parallel. The plurality of second capacitor elements (C21) are arranged along a second direction intersecting with a first direction in which the first capacitor (C1) and the second capacitor (C2) are arranged side by side.

[0119] According to this aspect, the electrostatic capacitance of the second capacitor (C2) can be easily adjusted by the number of the second capacitor elements (C21).

[0120] In the capacitor (1) of the ninth aspect, in addition to any one of the first to eighth aspects, the electrostatic capacitance of the first capacitor (C1) is larger than the electrostatic capacitance of the second capacitor (C2).

[0121] According to this aspect, the inductance between the first capacitor (C1) having a larger electrostatic capacitance than the second capacitor (C2) and the first external connection terminal (T1) can be reduced compared to the inductance between the second capacitor (C2) and the first external connection terminal (T1).

[0122] The power conversion device (2) of the tenth embodiment comprises: a capacitor (1) of any one of the first to ninth embodiments; a converter circuit (3); and an inverter circuit (4). The converter circuit (3) performs voltage conversion of a DC voltage input from a DC power supply (6). The inverter circuit (4) converts the output voltage of the converter circuit (3) into an AC voltage. The first external connection terminal (T1) and the second external connection terminal (T2) are connected to the input portion of the inverter circuit (4). The first external connection terminal (T1) and the third external connection terminal (T3) are connected to the connection portion between the DC power supply (6) and the converter circuit (3).

[0123] According to this embodiment, the inductance between the first external connection terminal (T1) and the first capacitor (C1) can be reduced compared to the inductance between the first external connection terminal (T1) and the second capacitor (C2). Therefore, the inductance between the switching element of the inverter circuit (4) connected to the first capacitor (C1) and the first capacitor (C1) can be reduced, and the voltage applied to the switching element when performing a switching operation can be reduced.

[0124] The structures according to the second to ninth aspects are not essential structures of the capacitor (1) and can be omitted as appropriate.

[0125] Description of Reference Numerals

[0126] 1 Capacitor

[0127] 2 Power conversion device

[0128] 3 Converter circuit

[0129] 4 Inverter circuit

[0130] 6 DC power supply

[0131] 30 Bus Bar 1

[0132] 40 Bus Bar 2

[0133] 50 Bus Bar 3

[0134] 60, 70 Power input terminal board

[0135] 200 Shell

[0136] 201 Opening

[0137] A1 1st size

[0138] A2 2nd size

[0139] C1 Capacitor 1

[0140] C2 Second capacitor

[0141] C11 1st capacitor element

[0142] C21 Second capacitor element

[0143] E1 Electrode 1

[0144] E2 Second electrode

[0145] E3 Electrode 3

[0146] E4 4th electrode

[0147] T1 1st external connection terminal

[0148] T2 2nd external connection terminal

[0149] T3 The third external connection terminal.

Claims

1. A capacitor having: A first capacitor having a first electrode and a second electrode; A second capacitor having a third electrode and a fourth electrode; a first bus bar having a first external connection terminal connected to the first electrode and the third electrode; a second bus bar having a second external connection terminal connected to the second electrode; a third bus bar having a third external connection terminal connected to the fourth electrode; and a housing for accommodating the first capacitor, the second capacitor, the first bus bar, the second bus bar, and the third bus bar in a state where at least a portion of each of the first external connection terminal, the second external connection terminal, and the third external connection terminal is exposed to the outside from the opening, The first electrode is connected to the first bus bar at a position closer to the first external connection terminal than the third electrode.

2. The capacitor according to claim 1, wherein The first capacitor and the second capacitor are housed side by side inside the housing so that the first capacitor is disposed between the second capacitor and the opening.

3. The capacitor according to claim 2, wherein: In the first direction in which the first capacitor and the second capacitor are arranged side by side, a first dimension between a connection point where the first bus bar is connected to the first electrode and the first external connection terminal is shorter than a second dimension between a connection point where the first bus bar is connected to the third electrode and the first external connection terminal.

4. The capacitor according to claim 1, wherein The capacitor is used in a power conversion device having a converter circuit for converting a DC voltage input from a DC power supply, and an inverter circuit for converting an output voltage of the converter circuit into an AC voltage. The first external connection terminal and the second external connection terminal are connected to an input portion of the inverter circuit. The first external connection terminal and the third external connection terminal are connected to a connection portion between the DC power supply and the converter circuit.

5. The capacitor according to claim 4, wherein: The capacitor also has a pair of power input terminal boards. The first external connection terminal is connected to the DC power supply via one of the pair of power input terminal boards. The third external connection terminal is connected to the DC power supply via the other of the pair of power input terminal blocks.

6. The capacitor according to claim 5, wherein: The pair of power input terminal boards are arranged outside the housing.

7. The capacitor according to claim 1, wherein The first capacitor includes a plurality of first capacitor elements connected in parallel, The plurality of first capacitor elements are arranged along a second direction intersecting a first direction in which the first capacitors and the second capacitors are arranged side by side.

8. The capacitor according to claim 1, wherein The second capacitor includes a plurality of second capacitor elements connected in parallel, The plurality of second capacitor elements are arranged along a second direction intersecting a first direction in which the first capacitors and the second capacitors are arranged side by side.

9. The capacitor according to claim 1, wherein: The electrostatic capacitance of the first capacitor is larger than the electrostatic capacitance of the second capacitor.

10. A power conversion device comprising: The capacitor according to any one of claims 1 to 9; a converter circuit that performs voltage conversion of a DC voltage input from a DC power supply; and an inverter circuit, which converts the output voltage of the converter circuit into an AC voltage, The first external connection terminal and the second external connection terminal are connected to an input portion of the inverter circuit. The first external connection terminal and the third external connection terminal are connected to a connection portion between the DC power supply and the converter circuit.

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