Power conversion device

Abstract

A power conversion device according to the present disclosure comprises: a capacitor including an electrode and a capacitor terminal electrically connected to the electrode; a power module having a power module terminal electrically connected to the capacitor terminal; a bus bar having a bus bar terminal electrically connected to the capacitor terminal or the power module terminal; and a terminal overlap part in which respective portions of the capacitor terminal, the power module terminal and the bus bar terminal overlap. The terminal overlap part includes a joint part in which the capacitor terminal, the power module terminal, and the bus bar terminal have been fused together.

Description

Power Conversion Device

[0001] The present disclosure relates to a power conversion device.

[0002] A power conversion device in which a power module and a capacitor are connected by a bus bar is known. The power conversion device includes, for example, an inverter or a converter, and converts power, such as from AC to DC, from DC to AC, or converts frequency.

[0003] For example, Patent Document 1 discloses an inverter unit having a power module, a smoothing capacitor module, and plate-shaped positive and negative bus bars that electrically connect the power module and the capacitor module.

[0004] Japanese Patent Application Laid-Open No. 2022-128662

[0005] The inverter unit of Patent Document 1 still has room for improvement in terms of reducing inductance.

[0006] The present disclosure provides a power conversion device capable of reducing inductance.

[0007] A power conversion device according to one aspect of the present disclosure comprises: a capacitor including an electrode and a capacitor terminal electrically connected to the electrode; a power module having a power module terminal electrically connected to the capacitor terminal; a busbar having a busbar terminal electrically connected to the capacitor terminal or the power module terminal; and a terminal overlapping portion in which the capacitor terminal, the power module terminal, and the busbar terminal partially overlap, wherein the terminal overlapping portion includes a joint portion in which the capacitor terminal, the power module terminal, and the busbar terminal are fused and integrated.

[0008] According to the present disclosure, it is possible to provide a power conversion device capable of reducing inductance.

[0009] 5 is an enlarged view of a region R2 of FIG. 2; FIG. 5 is an enlarged view of a region R3 of FIG. 5; FIG. 5 is a circuit diagram showing a configuration of the power conversion device of FIG. 1A; FIG. 1A is a diagram showing an example of a manufacturing process for the power conversion device of FIG. 1A; FIG. 1A is a diagram showing an example of a manufacturing process for the power conversion device of FIG. 1A; FIG. 1A is a diagram showing an example of a manufacturing process for the power conversion device of FIG. 1A;

[0010] (Background to the Disclosure) Some power conversion devices, such as inverter devices, are provided with a capacitor for smoothing DC current from a power source. For example, the inverter unit described in Patent Document 1 includes a power module, a capacitor module, and positive and negative bus bars. In the inverter unit of Patent Document 1, the power module converts DC power to AC power, and the capacitor module smoothes the DC voltage supplied from the DC power source. Furthermore, in the inverter unit of Patent Document 1, the positive and negative bus bars electrically connect the power module and the capacitor module.

[0011] In the inverter unit of Patent Document 1, the power module and the capacitor module are connected by a positive bus bar and a negative bus bar. Using bus bars to connect the power module and the capacitor module increases the distance from the power module to the capacitor module. As a result, the inverter unit of Patent Document 1 has a problem in that parasitic inductance between the power module and the capacitor module increases.

[0012] Surge voltages occur when the switching elements in a power module are turned off. If the parasitic inductance of a power conversion device is large, the surge voltage will increase and exceed the withstand voltage of the switching elements, increasing the risk of damage to the switching elements. Slowing down the switching speed can suppress surge voltages, but slowing down the switching speed can cause other issues such as switching loss and temperature rise.

[0013] Furthermore, if the parasitic inductance of the power conversion device is large, the oscillation of voltage and current that occurs during switching, known as ringing, becomes large, which causes a problem of noise being generated due to the ringing.

[0014] Therefore, the present inventors have studied a power conversion device that can reduce parasitic inductance, and have arrived at the following invention.

[0015] (First embodiment) [Overall configuration] Fig. 1A is a perspective view illustrating a power conversion device 1 according to a first embodiment of the present disclosure. Fig. 1B is a plan view illustrating the power conversion device 1 according to the first embodiment of the present disclosure. Fig. 2 is an A-A cross-sectional view of the power conversion device 1 of Fig. 1A. Fig. 3 is an enlarged view of a region R1 of Fig. 2. Fig. 4 is an enlarged view of a region R2 of Fig. 2. Fig. 5 is a B-B cross-sectional view of the power conversion device 1 of Fig. 1A. Fig. 6 is an enlarged view of a region R3 of Fig. 5. Fig. 7 is a circuit diagram illustrating a configuration of the power conversion device 1 of Fig. 1A. Note that the X, Y, and Z directions in the figure indicate the horizontal, vertical, and height directions of the power conversion device 1, respectively.

[0016] As shown in FIGS. 1A and 1B , the power conversion device 1 includes a capacitor 10, a power module 20, and a bus bar 30. The power conversion device 1 smoothes DC power input from a DC power source (not shown) connected to input terminals 35 and 36 of the bus bar 30 using the capacitor 10, converts the power using the power module 20, and outputs the power from output terminals 23 of the power module 20. In this embodiment, as shown in FIG. 7 , the power conversion device 1 configures a three-phase inverter. Therefore, the power conversion device 1 includes three capacitors 10 and three power modules 20 corresponding to each phase. The number of each of the capacitors 10 and the power modules 20 is not limited to three, and may be one or two or more of each. Furthermore, the power conversion device 1 is not limited to an inverter, and may be any device that converts power, such as a device that converts an input current from AC to DC.

[0017] 2 and 5 , capacitor 10 includes electrodes 12 and 13 and capacitor terminals 14 and 15 electrically connected to electrodes 12 and 13. Electrodes 12 and 13 are end electrodes formed on both end surfaces of capacitor 10. In this embodiment, capacitor 10 is a capacitor module in which capacitor element 11, with capacitor terminals 14 and 15 connected to electrodes 12 and 13, is housed in case 16 and sealed with resin (not shown). Note that capacitor 10 may also be configured such that capacitor element 11 is not housed in case 16, and capacitor terminals 14 and 15 are connected to electrodes 12 and 13.

[0018] In this embodiment, the electrodes of capacitor 10 include, for example, a first electrode 12 which is a positive electrode and a second electrode 13 which is a negative electrode. In addition, in this embodiment, the capacitor terminals of capacitor 10 include, for example, a first capacitor terminal 14 connected to first electrode 12 and a second capacitor terminal 15 connected to second electrode 13.

[0019] As shown in Figures 2 to 4, the capacitor terminals 14, 15 have extensions 14a, 15a and contact portions 14b, 15b. The extensions 14a, 15a are electrically connected to the electrodes 12, 13 and extend from the first surface 10a of the capacitor 10. In other words, the extensions 14a, 15a extend from the electrodes 12, 13 of the capacitor 10 in the height direction (Z direction) of the power conversion device 1. In the example of Figure 2, the first surface 10a of the capacitor 10 is a plane parallel to the XY plane. The contact portions 14b, 15b extend in a bent manner from the ends of the extensions 14a, 15a. Therefore, the capacitor terminals 14, 15 are each formed in an L shape when viewed from the Y direction. When viewed from the direction in which the extensions 14a, 15a extend (Z direction), the contact portions 14b, 15b are arranged to overlap the first surface 10a. Therefore, when viewed from the height direction of the power conversion device 1 (Z direction), the capacitor terminals 14, 15 are arranged in positions that overlap the capacitor 10. Because the capacitor terminals 14, 15 overlap the capacitor 10 when viewed from the height direction of the power conversion device 1, the capacitor terminals 14, 15 can be arranged without protruding from the capacitor 10 in a plan view. This allows the power conversion device 1 to be made smaller.

[0020] The capacitor terminals 14 and 15 are formed of plate-shaped metal. In this embodiment, the capacitor terminals 14 and 15 are each formed of a copper plate.

[0021] Capacitor element 11 is, for example, a film capacitor composed of a laminate of dielectric films. Capacitor element 11 is formed by stacking dielectric films each having a metal vapor deposition film formed on its surface and then rolling them. In this embodiment, the rolled dielectric film is pressed into a flat shape, so that capacitor element 11 is formed into a columnar shape with an oval cross section, as shown in FIG. 5 . End electrodes 12 and 13 are provided on the end faces of capacitor element 11. Note that capacitor element 11 is not limited to a film capacitor and may be an electrolytic capacitor, a ceramic capacitor, or the like.

[0022] <Power Module> The power module 20 is configured by providing power module terminals 21 and 22 on a main body 24 that houses a semiconductor element (not shown). In this embodiment, the power module 20 also has an output terminal 23. The output terminal 23 is connected to an application such as a motor (not shown).

[0023] 1A and 1B , the power module terminals 21, 22 are arranged to protrude outward from one side of the main body 24, which is rectangular in plan view when viewed from the Z direction. The output terminal 23 is arranged to protrude outward from the side of the main body 24 opposite to the side on which the power module terminals 21, 22 are arranged. In other words, the power module terminals 21, 22 and the output terminal 23 are arranged to protrude on opposite sides from the main body 24.

[0024] The power module terminals 21, 22 are electrically connected to the capacitor terminals 14, 15 of the capacitor 10, respectively. In this embodiment, the power module terminals include a first power module terminal 21 connected to the first capacitor terminal 14 and a second power module terminal 22 connected to the second capacitor terminal 15.

[0025] The power module terminals 21 and 22 are each formed of a metal plate. In this embodiment, the power module terminals 21 and 22 are each formed of a copper plate.

[0026] 2 and 3, the first power module terminal 21 is disposed so as to overlap the contact portion 14b of the first capacitor terminal 14 via a bus bar terminal 33 (described later). Similarly, the second power module terminal 22 is disposed so as to overlap the contact portion 15b of the second capacitor terminal 15 via a bus bar terminal 34 (described later) as shown in FIGS. 2 and 4 to 6.

[0027] <Busbars> The busbars 30 electrically connect the DC power supply to the capacitor 10 and the power module 20. In the present embodiment, the busbars 30 include a first busbar 31 on the positive electrode side and a second busbar 32 on the negative electrode side. The first busbar 31 includes a first busbar terminal 33 electrically connected to the first capacitor terminal 14 or the first power module terminal 21, and the second busbar 32 includes a second busbar terminal 34 electrically connected to the second capacitor terminal 15 or the second power module terminal 22.

[0028] The bus bar 30 is formed of a metal plate. In this embodiment, the bus bar 30 is formed of, for example, a copper plate.

[0029] 1A and 1B , the first bus bar 31 and the second bus bar 32 are arranged to overlap each other. In addition, insulating paper 60 is arranged between the first bus bar 31 and the second bus bar 32 to insulate the first bus bar 31 and the second bus bar 32. By arranging the first bus bar 31 and the second bus bar 32 to overlap each other, the electric field generated by the current flowing through the first bus bar 31 and the electric field generated by the current flowing through the second bus bar 32 cancel each other out, thereby reducing the parasitic inductance of the power conversion device 1.

[0030] 1A and 1B, in this embodiment, the first bus bar 31 has a first input terminal 35 arranged on the opposite side from the first bus bar terminal 33. Similarly, in this embodiment, the second bus bar 32 has a second input terminal 36 arranged on the opposite side from the second bus bar terminal 34.

[0031] As shown in Fig. 3 , in this embodiment, the first capacitor terminal 14, the first bus bar terminal 33, and the first power module terminal 21 are sequentially stacked in the thickness direction. More specifically, the first bus bar terminal 33 is stacked on the contact portion 14b of the first capacitor terminal 14, and the first power module terminal 21 is stacked on the first bus bar terminal 33 to form a first terminal overlapping portion 51. A first joint portion 41 is provided in the first terminal overlapping portion 51. The first joint portion 41 is formed by, for example, laser welding the portion where the first capacitor terminal 14, the first bus bar terminal 33, and the first power module terminal 21 overlap, i.e., the first terminal overlapping portion 51. In the first joint portion 41, the first capacitor terminal 14, the first bus bar terminal 33, and the first power module terminal 21 are fused and integrated. That is, the first joint portion 41 is a compatible portion where the first capacitor terminal 14, the first bus bar terminal 33, and the first power module terminal 21 are fused together as a single unit.

[0032] As shown in FIGS. 2 and 4 to 6 , in this embodiment, the second capacitor terminals 15, the second bus bar terminals 34, and the second power module terminals 22 are also similarly arranged in a stacked order in the thickness direction. More specifically, the second bus bar terminals 34 are stacked on the contact portions 15b of the second capacitor terminals 15, and the second power module terminals 22 are stacked on the second bus bar terminals 34 to form second terminal overlapping portions 52. A second joint portion 42 is provided in the second terminal overlapping portion 52. Similar to the first joint portion 41, the second joint portion 42 is formed by, for example, laser welding the portion where the second capacitor terminals 15, the second bus bar terminals 34, and the second power module terminals 22 overlap, i.e., the second terminal overlapping portion 52. In the second joint portion 42, the second capacitor terminals 15, the second bus bar terminals 34, and the second power module terminals 22 are fused and integrated. That is, the second joint portion 42 is a compatible portion formed by the second capacitor terminal 15, the second bus bar terminal 34, and the second power module terminal 22 being mixed and integrated together.

[0033] 1A and 1B, the first bonding portions 41 and the second bonding portions 42 are arranged side by side at intervals in the first direction (X direction). More specifically, the first bonding portions 41 and the second bonding portions 42 are arranged alternately at equal intervals in the first direction. Furthermore, as shown in FIG. 2, the first bonding portions 41 and the second bonding portions 42 are provided at positions that are approximately the same height from the bottom surface of the capacitor 10. Therefore, for example, when forming the bonding portions 41 and 42 by laser welding, the first bonding portion 41 and the second bonding portion 42 can be formed by scanning a laser in one direction, thereby simplifying the manufacturing process and reducing manufacturing costs.

[0034] By welding the capacitor terminals 14, 15, the bus bar terminals 33, 34, and the power module terminals 21, 22 together, they can be electrically connected to each other. In particular, as shown in Figures 3 and 4, the distances d1, d2 between the capacitor terminals 14, 15 and the power module terminals 21, 22 can be shortened, which enhances the effect of reducing the parasitic inductance of the power conversion device 1. In this embodiment, the distances d1, d2 between the capacitor terminals 14, 15 and the power module terminals 21, 22 are the distances corresponding to the thickness of the bus bar 30.

[0035] By reducing the parasitic inductance, surge voltages that occur when the switching elements of the power module 20 are turned off can be suppressed, preventing damage to the switching elements due to voltages exceeding their withstand voltages. Furthermore, suppressing surge voltages can improve the switching speed of the switching elements, thereby reducing switching losses and improving the conversion efficiency of the power conversion device 1. Furthermore, reducing switching losses can also suppress heat generation in the power conversion device 1 itself. Furthermore, ringing in voltage or current that occurs when the switching elements are switched can also be reduced, thereby enabling the power conversion device 1 to have lower noise levels. Furthermore, reducing heat generation or noise can reduce the number of cooling components or cooling materials, or noise suppression components, thereby enabling the power conversion device 1 to be made smaller, lighter, and less expensive.

[0036] 3 to 4 and 6, the joints 41, 42 are formed to penetrate the bus bar terminals 33, 34 and the power module terminals 21, 22, but terminate just before the surfaces 14c, 15c of the contact portions 14b, 15b of the capacitor terminals 14, 15 that are opposite the surfaces on which the power module terminals 21, 22 and the bus bar terminals 33, 34 are arranged. In other words, the joints 41, 42 do not penetrate the capacitor terminals 14, 15. By not having the joints 41, 42 penetrate the capacitor terminals 14, 15, it is possible to prevent the laser energy during welding from affecting the capacitor 10.

[0037] [Manufacturing Method] Figures 8 to 11 are diagrams showing an example of a manufacturing process for the power conversion device 1 of Figure 1A. An example of a manufacturing method for the power conversion device 1 will be described with reference to Figures 8 to 11.

[0038] First, the capacitors 10 are prepared as shown in Fig. 8. In this embodiment, the power conversion device 1 has three capacitors 10, and therefore the three capacitors 10 are arranged side by side in the first direction (X direction).

[0039] Next, as shown in Fig. 9, a bus bar 30 including a first bus bar 31 and a second bus bar 32 is arranged. Insulating paper 60 is placed between the first bus bar 31 and the second bus bar 32. At this time, the bus bar 30 is placed on the capacitor 10 so that the first bus bar terminal 33 of the first bus bar 31 is positioned at the contact portion 14b of the first capacitor terminal 14 of the capacitor 10, and the second bus bar terminal 34 of the second bus bar 32 is positioned at the contact portion 15b of the second capacitor terminal 15 of the capacitor 10. The bus bar 30 is fixed with a jig or the like to prevent misalignment between the capacitor terminals 14, 15 and the bus bar terminals 33, 34.

[0040] Next, as shown in FIG. 10 , the power modules 20 are arranged on the capacitors 10 and the bus bars 30. In this embodiment, the power conversion device 1 has three power modules 20, so three power modules 20 are prepared. The three power modules 20 are arranged so that the first power module terminal 21 of each power module 20 overlaps the contact portion 14b of the first capacitor terminal 14 of each capacitor 10. Similarly, the second power module terminal 22 of each power module 20 overlaps the contact portion 15b of the second capacitor terminal 15 of each capacitor 10. The three power modules 20 are also fixed with a jig or the like to prevent the capacitor terminals 14, 15, bus bar terminals 33, 34, and power module terminals 21, 22 from shifting from their overlapping states.

[0041] 11 , a region pa1 of the first terminal overlapping portion 51 where the first capacitor terminal 14, the first bus bar terminal 33, and the first power module terminal 21 overlap, and a region pa2 of the second terminal overlapping portion 52 where the second capacitor terminal 15, the second bus bar terminal 34, and the second power module terminal 22 overlap, are welded using a laser or the like. At this time, the laser is irradiated in the direction of arrow L1.

[0042] Laser welding in areas pa1 and pa2 of terminal overlapping portions 51 and 52 forms joints 41 and 42, completing the power conversion device 1 of Figures 1A and 1B. By moving a laser irradiation unit (not shown) in a first direction (X direction) and irradiating the laser downward (-Z direction), six joints 41 and 42 can be formed. Because areas pa1 and pa2 and capacitors 10 are each aligned in the first direction, multiple joints 41 and 42 can be formed by sliding the laser irradiation unit in one direction, simplifying the manufacturing process for power conversion device 1.

[0043] According to the above-described manufacturing method, the capacitor terminals 14, 15, the bus bar terminals 33, 34, and the power module terminals 21, 22 can be welded together at one time, which simplifies the manufacturing process and reduces manufacturing costs.

[0044] Furthermore, since the capacitor terminals 14, 15, the bus bar terminals 33, 34, and the power module terminals 21, 22 can be welded at the same location, the area required for welding is reduced, allowing the bus bar size to be smaller. Furthermore, by reducing the number of welding locations, the manufacturing process is simplified, shortening manufacturing time and further reducing manufacturing costs.

[0045] [Effects] According to the above-described embodiment, the following effects can be achieved.

[0046] The power conversion device 1 according to the first embodiment includes a capacitor 10, a power module 20, a bus bar 30, and terminal overlapping portions 51 and 52. The capacitor 10 has electrodes 12 and 13 and capacitor terminals 14 and 15 electrically connected to the electrodes 12 and 13. The power module 20 has power module terminals 21 and 22 electrically connected to the capacitor terminals 14 and 15. The bus bar 30 is electrically connected to the capacitor terminals 14 and 15 or the power module terminals 21 and 22. The terminal overlapping portions 51 and 52 are portions where the capacitor terminals 14 and 15, the power module terminals 21 and 22, and the bus bar terminals 33 and 34 partially overlap with each other. The terminal overlapping portions 51 and 52 include joints 41 and 42 where the capacitor terminals 14 and 15, the power module terminals 21 and 22, and the bus bar terminals 33 and 34 are fused and integrated with each other.

[0047] With this configuration, the distance between the capacitor terminals 14, 15 and the power module terminals 21, 22 can be shortened, and the parasitic inductance of the power conversion device 1 can be reduced.

[0048] The bus bar terminals 33 and 34 may be arranged on the capacitor terminals 14 and 15 , and the power module terminals 21 and 22 may be arranged on the bus bar terminals 33 and 34 .

[0049] With this configuration, it is possible to provide a product in which the bus bar 30 is connected to the capacitor 10. Since the power module 20 can be connected later to a product in which the bus bar 30 is connected to the capacitor 10, this leads to diversification of product forms.

[0050] The joints 41, 42 may be provided to penetrate the power module terminals 21, 22 and the bus bar terminals 33, 34, and may terminate just before the surface of the capacitor terminals 14, 15 opposite to the surface on which the power module terminals 21, 22 and the bus bar terminals 33, 34 are arranged.

[0051] With this configuration, the joints 41 and 42 do not penetrate the capacitor terminals 14 and 15, so that the effect of laser energy on the capacitor during welding can be reduced.

[0052] The capacitor terminals 14, 15, the power module terminals 21, 22, and the bus bar terminals 33, 34 may have a plate shape and be arranged so as to overlap each other in the thickness direction.

[0053] With this configuration, the wiring distance between the capacitor 10 and the power module 20 can be shortened while ensuring the contact area of ​​each terminal.

[0054] The electrodes may include a first electrode 12 and a second electrode 13. The capacitor terminals may include a first capacitor terminal 14 connected to the first electrode 12 and a second capacitor terminal 15 connected to the second electrode 13. The power module terminals may include a first power module terminal 21 connected to the first capacitor terminal 14 and a second power module terminal 22 connected to the second capacitor terminal 15. The busbars 30 may include a first busbar 31 connected to the first capacitor terminal 14 or the first power module terminal 21, and a second busbar 32 connected to the second capacitor terminal 15 or the second power module terminal 22. The first busbar 31 may have a first busbar terminal 33. The second busbar 32 may have a second busbar terminal 34. The joints may include a first joint portion 41 provided in a first terminal overlap portion 51 where the first capacitor terminal 14, the first power module terminal 21, and the first bus bar terminal 33 overlap, and a second joint portion 42 provided in a second terminal overlap portion 52 where the second capacitor terminal 15, the second power module terminal 22, and the second bus bar terminal 34 overlap. The first joint portion 41 and the second joint portion 42 may be arranged at an interval in the first direction in a plan view.

[0055] With this configuration, the manufacturing process during laser welding can be simplified, thereby reducing manufacturing costs.

[0056] The power module 20 may further include an output terminal 23 disposed on the opposite side to the first power module terminal 21 and the second power module terminal 22 .

[0057] Such a configuration allows the size of the power conversion device 1 in the lateral direction (X direction) to be reduced, which contributes to the miniaturization of the power conversion device 1.

[0058] The first bus bar 31 may have a first input terminal 35 arranged opposite the first bus bar terminal 33, and the second bus bar 32 may have a second input terminal 36 arranged opposite the second bus bar terminal 34.

[0059] Such a configuration allows the size of the power conversion device 1 in the lateral direction (X direction) to be reduced, which contributes to the miniaturization of the power conversion device 1.

[0060] The capacitor terminals 14, 15 may have extension portions 14a, 15a electrically connected to the electrodes 12, 13 and extending from the first surface 10a of the capacitor 10, and contact portions 14b, 15b that extend in a bent manner from the ends of the extension portions 14a, 15a and are positioned overlapping the first surface 10a when viewed from the direction in which the extension portions 14a, 15a extend.

[0061] With this configuration, the contact portions 14b and 15b are positioned to face the capacitor 10, so that the bus bar 30 and the power module 20 can be connected more stably.

[0062] The capacitor terminals 14, 15, the power module terminals 21, 22, and the bus bar terminals 33, 34 may be made of copper.

[0063] With this configuration, the thermal conductivity of each terminal can be improved, and a highly reliable power converter can be provided.

[0064] [Modification] In the above-described embodiment, the power conversion device 1 is a three-phase inverter, but is not limited to this. The power conversion device 1 may be a converter or other power electronics product that performs power conversion using the capacitor 10 and the power module 20.

[0065] In the above-described embodiment, an example in which the power conversion device 1 has three capacitors 10 and three power modules 20 has been described, but the present invention is not limited to this. The power conversion device 1 may include any number of capacitors 10 and power modules 20.

[0066] Fig. 12 is a perspective view showing a power conversion device 1A according to a first modification of the first embodiment. Fig. 13 is a CC cross-sectional view of the power conversion device 1A of Fig. 12. Fig. 14 is a DD cross-sectional view of the power conversion device 1A of Fig. 12. As shown in Figs. 12 to 14, power module terminals 21, 22 may be mounted on capacitor terminals 14, 15, and bus bar terminals 33, 34 may be mounted on the power module terminals 21, 22.

[0067] As shown in Figures 12 to 14, in the power conversion device 1A, the first power module terminal 21 is placed on the contact portion 14b of the first capacitor terminal 14, and the first bus bar terminal 33 is placed on the first power module terminal 21. Similarly, in the power conversion device 1A, the second power module terminal 22 is placed on the contact portion 15b of the second capacitor terminal 15, and the second bus bar terminal 34 is placed on the second power module terminal 22. Therefore, in the power conversion device 1A, the capacitor terminals 14, 15, the power module terminals 21, 22, and the bus bar terminals 33, 34 are stacked in this order at the terminal overlap portions 53, 54. This brings the capacitor terminals 14, 15 into direct contact with the power module terminals 21, 22, thereby further shortening the distance between the capacitor terminals 14, 15 and the power module terminals 21, 22. This further improves the effect of reducing parasitic inductance.

[0068] (Second embodiment) A power conversion device 1B according to a second embodiment of the present disclosure will be described. In the second embodiment, differences from the first embodiment will be mainly described. In the second embodiment, the same or equivalent configurations as those in the first embodiment will be denoted by the same reference numerals. Furthermore, in the second embodiment, descriptions that overlap with those in the first embodiment will be omitted.

[0069] Fig. 15 is a perspective view showing a power conversion device 1B according to the second embodiment. Fig. 16 is a cross-sectional view taken along the line E-E of the power conversion device 1B of Fig. 15. As shown in Figs. 15 and 16, the second embodiment differs from the first embodiment in that power module terminals 121, 122 are arranged to overlap some of the capacitor terminals 14, 15, and bus bar terminals 133, 134 are arranged to overlap other portions of the capacitor terminals 14, 15. The configurations of the capacitor 10, the power module 120, and the bus bar 130 are the same as those of the first embodiment, and therefore description thereof will be omitted.

[0070] 15 and 16 , in this embodiment, power module terminals 121 and 122 of the power module 20 are respectively arranged in parts of the contact portions 14b and 15b (see FIG. 2 ) of the capacitor terminals 14 and 15. A third joint portion 45 is formed in a third terminal overlap portion 55 where the capacitor terminals 14 and 15 and the power module terminals 121 and 122 overlap. Furthermore, in this embodiment, bus bar terminals 133 and 134 of the bus bar 130 are respectively arranged in other parts of the contact portions 14b and 15b (see FIG. 2 ) of the capacitor terminals 14 and 15. A fourth joint portion 46 is formed in a fourth terminal overlap portion 56 where the capacitor terminals 14 and 15 and the bus bar terminals 133 and 134 overlap.

[0071] In this embodiment, the third bonding portions 45 are arranged at equal intervals in the first direction (X direction), and the fourth bonding portions 46 are also arranged at equal intervals in the first direction. Furthermore, as shown in FIG. 16 , the third bonding portions 45 and the fourth bonding portions 46 are provided at the same height from the bottom surface of the capacitor 10.

[0072] [Effects] According to the above-described embodiment, the following effects can be achieved.

[0073] The capacitor terminals 14, 15 can be brought into direct contact with the power module terminals 121, 122, and the capacitor terminals 14, 15 can be brought into direct contact with the bus bar terminals 133, 134. This shortens the distance between the capacitor terminals 14, 15 and the power module terminals 121, 122, improving the effect of reducing parasitic inductance. Furthermore, because the capacitor terminals 14, 15 can be brought into direct contact with the bus bar terminals 133, 134, the power module 120 can be retrofitted to a product in which the capacitor 10 and the bus bar 130 are connected, thereby diversifying product forms.

[0074] (Summary of Embodiments) (1) A power conversion device according to the present disclosure includes a capacitor including an electrode and a capacitor terminal electrically connected to the electrode, a power module having a power module terminal electrically connected to the capacitor terminal, a busbar having a busbar terminal electrically connected to the capacitor terminal or the power module terminal, and a terminal overlap portion in which the capacitor terminal, the power module terminal, and the busbar terminal overlap with each other in part, and the terminal overlap portion includes a joint portion in which the capacitor terminal, the power module terminal, and the busbar terminal are fused together.

[0075] (2) In the power conversion device of (1), bus bar terminals may be mounted on the capacitor terminals, and power module terminals may be mounted on the bus bar terminals.

[0076] (3) In the power conversion device of (1), power module terminals may be mounted on the capacitor terminals, and bus bar terminals may be mounted on the power module terminals.

[0077] (4) In the power conversion device of any one of (1) to (3), the joint may be provided to penetrate the power module terminal and the bus bar terminal and terminate just before the surface of the capacitor terminal opposite to the surface on which the power module terminal and the bus bar terminal are arranged.

[0078] (5) In the power conversion device according to any one of (1) to (4), the capacitor terminal, the power module terminal, and the bus bar terminal may have a plate-like shape and be arranged so as to overlap each other in the thickness direction.

[0079] (6) In the power conversion device of any one of (1) to (5), the electrodes may include a first electrode and a second electrode, the capacitor terminals may include a first capacitor terminal connected to the first electrode and a second capacitor terminal connected to the second electrode, the power module terminals may include a first power module terminal connected to the first capacitor terminal and a second power module terminal connected to the second capacitor terminal, the busbars may include a first busbar connected to the first capacitor terminal or the first power module terminal and a second busbar connected to the second capacitor terminal or the second power module terminal, the first busbar has first busbar terminals, and the second busbar has second busbar terminals, the joints may include a first joint provided at a first terminal overlapping portion where the first capacitor terminal, the first power module terminal, and the first busbar terminal overlap, and a second joint provided at a second terminal overlapping portion where the second capacitor terminal, the second power module terminal, and the second busbar terminal overlap, and the first joint and the second joint may be arranged side by side at an interval in the first direction in a plan view.

[0080] (7) In the power conversion device of (6), the power module may further include an output terminal disposed on the opposite side to the first power module terminal and the second power module terminal.

[0081] (8) In the power conversion device of (6) or (7), the first bus bar may further have a first input terminal arranged on the opposite side to the first bus bar terminal, and the second bus bar may further have a second input terminal arranged on the opposite side to the second bus bar terminal.

[0082] (9) A power conversion device includes: a capacitor including an electrode and a capacitor terminal electrically connected to the electrode; a power module having a power module terminal electrically connected to the capacitor terminal; a busbar having a busbar terminal electrically connected to the capacitor terminal; a third terminal overlapping portion in which a part of the capacitor terminal and the power module terminal are overlapped; and a fourth terminal overlapping portion in which another part of the capacitor terminal and the busbar terminal are overlapped, wherein the third terminal overlapping portion includes a third joint portion in which the capacitor terminal and the power module terminal are fused together, and the fourth terminal overlapping portion includes a fourth joint portion in which the capacitor terminal and the busbar terminal are fused together.

[0083] (10) In any one of the power conversion devices (1) to (9), the capacitor terminal may have an extension portion electrically connected to the electrode and extending from the first surface of the capacitor, and a contact portion that bends and extends from the end of the extension portion and is positioned overlapping the first surface when viewed from the direction in which the extension portion extends.

[0084] (11) In the power conversion device according to any one of (1) to (10), the capacitor terminals, the power module terminals, and the bus bar terminals may be made of copper.

[0085] The present invention is useful for power conversion devices used in various electronic devices, electrical devices, industrial devices, vehicle devices, etc.

[0086] REFERENCE SIGNS 1, 1A, 1B Power conversion device 10 Capacitor 10a First surface 12 Electrode (first electrode) 13 Electrode (second electrode) 14 Capacitor terminal (first capacitor terminal) 14a Extension portion 14b Contact portion 15 Capacitor terminal (second capacitor terminal) 15a Extension portion 15b Contact portion 20, 120 Power module 21, 121 Power module terminal (first power module terminal) 22, 122 Power module terminal (second power module terminal) 23, 123 Output terminal 30, 130 Bus bar 31, 131 First bus bar 32, 132 Second bus bar 33, 133 Bus bar terminal (first bus bar terminal) 34, 134 Bus bar terminal (second bus bar terminal) 35, 135 Input terminal (first input terminal) 36, 136 Input terminal (second input terminal) 41 Joint portion (first joint portion) 42 Joint portion (second joint portion) 45 Third joint portion 46 Fourth joint portion 51, 53 Terminal overlap portion (first terminal overlap portion) 52, 54 Terminal overlap portion (second terminal overlap portion) 55 Third terminal overlap portion 56 Fourth terminal overlap portion 120 Power module

Claims

1. A power conversion device comprising: a capacitor including an electrode and a capacitor terminal electrically connected to the electrode; a power module having a power module terminal electrically connected to the capacitor terminal; a busbar having a busbar terminal electrically connected to the capacitor terminal or the power module terminal; and a terminal overlapping portion in which the capacitor terminal, the power module terminal, and the busbar terminal overlap each other, wherein the terminal overlapping portion includes a joint where the capacitor terminal, the power module terminal, and the busbar terminal are fused together.

2. The power conversion device according to claim 1, wherein the bus bar terminals are mounted on the capacitor terminals, and the power module terminals are mounted on the bus bar terminals.

3. The power conversion device according to claim 1, wherein the power module terminals are mounted on the capacitor terminals, and the bus bar terminals are mounted on the power module terminals.

4. A power conversion device according to any one of claims 1 to 3, wherein the joint portion is provided so as to penetrate the power module terminal and the bus bar terminal, and terminates just before a surface of the capacitor terminal opposite to a surface on which the power module terminal and the bus bar terminal are arranged.

5. The power conversion device according to any one of claims 1 to 4, wherein the capacitor terminals, the power module terminals, and the bus bar terminals have a plate-like shape and are arranged overlapping each other in their thickness directions.

6. The electrodes include a first electrode and a second electrode, the capacitor terminals include a first capacitor terminal connected to the first electrode and a second capacitor terminal connected to the second electrode, the power module terminals include a first power module terminal connected to the first capacitor terminal and a second power module terminal connected to the second capacitor terminal, the busbars include a first busbar connected to the first capacitor terminal or the first power module terminal and a second busbar connected to the second capacitor terminal or the second power module terminal, the first busbar has a first busbar terminal, and the second busbar has a second busbar terminal, the joints include a first joint provided in a first terminal overlapping portion where the first capacitor terminal, the first power module terminal, and the first busbar terminal overlap, and a second joint provided in a second terminal overlapping portion where the second capacitor terminal, the second power module terminal, and the second busbar terminal overlap, and the first joint and the second joint are arranged side by side with a gap in a first direction in a plan view. The power conversion device according to claim 1 .

7. The power conversion device according to claim 6, wherein the power module further has an output terminal arranged on the opposite side to the first power module terminal and the second power module terminal.

8. A power conversion device as described in claim 6 or 7, wherein the first bus bar further has a first input terminal arranged opposite the first bus bar terminal, and the second bus bar further has a second input terminal arranged opposite the second bus bar terminal.

9. A power conversion device comprising: a capacitor having an electrode and a capacitor terminal electrically connected to the electrode; a power module having a power module terminal electrically connected to the capacitor terminal; a busbar having a busbar terminal electrically connected to the capacitor terminal; a third terminal overlapping portion in which a part of the capacitor terminal and the power module terminal are arranged overlapping; and a fourth terminal overlapping portion in which another part of the capacitor terminal and the busbar terminal are arranged overlapping, wherein the third terminal overlapping portion includes a third joint portion where the capacitor terminal and the power module terminal are melted and integrated, and the fourth terminal overlapping portion includes a fourth joint portion where the capacitor terminal and the busbar terminal are melted and integrated.

10. A power conversion device as claimed in any one of claims 1 to 9, wherein the capacitor terminal has an extension portion electrically connected to the electrode and extending from a first surface of the capacitor, and a contact portion that extends in a bent manner from an end of the extension portion and is positioned overlapping with the first surface when viewed from the direction in which the extension portion extends.

11. The power conversion device according to any one of claims 1 to 10, wherein the capacitor terminals, the power module terminals, and the bus bar terminals are made of copper.

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