Power conversion device

Abstract

This power conversion device (101) comprises: a first power conversion unit (11) and a second power conversion unit (12) that are adjacent to each other in a first direction (DR1); and a first insulating housing (21) and a second insulating housing (22) that are adjacent to each other in the first direction. The first power conversion unit is supported by the first insulating housing. The second power conversion unit is supported by the second insulating housing. The first insulating housing and the second insulating housing respectively have wall parts (20A, 20B) disposed between the first power conversion unit and the second power conversion unit. The power conversion device further comprises at least one first coupling member (41) that passes through and couples the respective wall parts of the first insulating housing and the second insulating housing. Terminals (31, 32A) of the first power conversion unit and the second power conversion unit are electrically connected to each other via the at least one first coupling member.

Description

Power Conversion Device

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

[0002] A power conversion device including a plurality of sub-modules (power conversion units) and an insulating housing is known as a power conversion device used in high voltage direct current (HVDC) transmission and the like (see, for example, Japanese Patent No. 6995259 (Patent Document 1)). The insulating housing supports each of the plurality of power conversion units and is provided to insulate the plurality of power conversion units from each other and from grounded objects such as surrounding walls.

[0003] Patent No. 6995259

[0004] In the power conversion device described in Patent Document 1, an opening is formed in the insulating housing in front of each power conversion unit, and conductive members protruding from the opening to the outside of the insulating housing electrically connect adjacent power conversion units. In the above power conversion device, the electric field on the surface of the conductive members located outside the insulating housing is high, so there is room for improvement in terms of suppressing the occurrence of dielectric breakdown.

[0005] A primary object of the present disclosure is to provide a power conversion device capable of suppressing the occurrence of dielectric breakdown.

[0006] A power conversion device according to the present disclosure includes a plurality of power conversion units, each having a first power conversion unit and a second power conversion unit adjacent to each other in a first direction, and a plurality of insulating housings, each having a first insulating housing and a second insulating housing adjacent to each other in the first direction. The first power conversion unit is supported by the first insulating housing. The second power conversion unit is supported by the second insulating housing. Each of the first power conversion unit and the second power conversion unit has a terminal. Each of the first insulating housing and the second insulating housing has a wall portion disposed between the first power conversion unit and the second power conversion unit. The power conversion device further includes at least one first connecting member that penetrates and connects the wall portions of the first insulating housing and the second insulating housing. The terminals of the first power conversion unit and the second power conversion unit are electrically connected to each other via the at least one first connecting member.

[0007] According to the power conversion device of the present disclosure, it is possible to suppress the occurrence of dielectric breakdown.

[0008] 1 is a circuit diagram of a power conversion device 100 according to an embodiment of the present disclosure. FIG. 2 is a circuit diagram of a power conversion unit 10 shown in FIG. 1. FIG. 3 is a perspective view for explaining the basic configuration of one power conversion unit 10 and one insulating housing 20 supporting it. FIG. 4 is a plan view of a power conversion device 101 according to a first embodiment. FIG. 5 is a partially enlarged plan view of a connection portion between a first insulating housing 21 and a second insulating housing 22 adjacent to each other in the X direction in the power conversion device 101. FIG. 6 is a partially enlarged plan view of a connection portion between a first insulating housing 21 and a second insulating housing 22 adjacent to each other in the X direction in a power conversion device 102 according to a second embodiment. FIG. 7 is a partially enlarged cross-sectional view of a connection portion between a first insulating housing 21 and a second insulating housing 22 adjacent to each other in the X direction in a power conversion device 103 according to a third embodiment. FIG. 8 is a plan view of a power conversion device 104 according to a fourth embodiment. FIG. 9 is a plan view of a power conversion device 105 according to a fifth embodiment. FIG. 10 is a plan view showing a modified example of the power conversion device 105 according to the fifth embodiment. FIG. 11 is a plan view of a power conversion device 106 according to a sixth embodiment. 10 is a partially enlarged plan view showing a configuration example of a connection portion between a first insulating casing 21 and a second insulating casing 22 adjacent to each other in the Z direction in a power conversion device 106. FIG. 11 is a plan view of a power conversion device 107 according to embodiment 7. FIG. 12 is a plan view of a power conversion device 200 according to a comparative example.

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Hereinafter, the same or corresponding parts will be denoted by the same reference numerals, and redundant description will not be repeated. <Configuration of Power Conversion Device 100> The power conversion device 100 is, for example, an MMC (Multilevel Modular Converter) type HVDC (High Voltage DC) converter. However, the power conversion device 100 is not limited to this.

[0010] As shown in Fig. 1, the power conversion device 100 has a plurality of sets of upper arms 110 and lower arms 120. The upper arms 110 and the lower arms 120 are electrically connected in series. Each of the plurality of sets of upper arms 110 and lower arms 120 is electrically connected in parallel. A transformer 130 is connected between the upper arms 110 and the lower arms 120. Each of the upper arms 110 and the lower arms 120 has a plurality of power conversion units 10 and a connection line 140 that electrically connects each of the plurality of power conversion units 10 in series.

[0011] In addition, among a plurality of power conversion units 10 electrically connected in series, the potential of the power conversion unit 10 at the DC end is generally higher than the potential of the power conversion unit 10 at the AC end. The potential difference between the DC end and the AC end is divided by the number of power conversion units 10, and the potential difference between the power conversion units 10 that are directly and electrically connected is constant when expressed without taking into account ripples during operation, etc.

[0012] The power conversion device 100 may further include, for example, at least one of piping for cooling the power conversion unit 10, communication equipment, other electrical equipment, and mechanical support equipment, although illustrations and descriptions of these are omitted in the present disclosure.

[0013] As shown in FIG. 2, the power conversion unit 10 includes, for example, switching elements 1a and 1b, diodes 2a and 2b, a capacitor 3, and connection lines 4a and 4b.

[0014] The switching element 1a and the switching element 1b are, for example, insulated gate bipolar transistors (IGBTs), and are connected in series.

[0015] The diode 2a and the diode 2b are electrically connected in parallel to the switching element 1a and the switching element 1b so as to be reverse-biased, respectively. The capacitor 3 is electrically connected in parallel to the switching element 1a and the switching element 1b, which are electrically connected in series.

[0016] The connection line 4a is connected to the emitter of the switching element 1a and the collector of the switching element 1b. The connection line 4b is connected to the emitter of the switching element 1b. The connection line 4a of one power conversion unit 10 is connected to the connection line 4b of another adjacent power conversion unit 10. In this way, the power conversion units 10 constitute a half-bridge type converter cell. Note that the power conversion units 10 may also constitute a full-bridge type converter cell.

[0017] In the power conversion device 100, each of the multiple power conversion units 10 is supported by an insulating housing.

[0018] 3 is a perspective view illustrating the basic configuration of one power conversion unit 10 and one insulating housing 20 supporting it in the power conversion device 100. Hereinafter, mutually orthogonal X, Y, and Z directions will be introduced. The X and Y directions correspond to the horizontal direction. The Z direction corresponds to the up-down direction.

[0019] 3, each power conversion unit 10 has a first side surface 10A, a second side surface 10B, a bottom surface 10C, a top surface 10D, a front surface 10E, and a back surface (not shown). The first side surface 10A, the second side surface 10B, the bottom surface 10C, the top surface 10D, the front surface 10E, and the back surface are surfaces of a case for the power conversion unit 10. This case is made of, for example, metal.

[0020] The first side surface 10A and the second side surface 10B of each power conversion unit 10 face one side and the other side in the X direction, respectively. The bottom surface 10C and the top surface 10D of each power conversion unit 10 face one side and the other side in the Z direction. The front surface 10E and the back surface of each power conversion unit 10 face one side and the other side in the Y direction. Hereinafter, the side facing the front surface 10E in the Y direction will be referred to as the front side, and the opposite side will be referred to as the back side.

[0021] The insulating housing 20 is made of an electrically insulating material, and may be made of any electrically insulating material, such as at least one selected from the group consisting of fiber reinforced plastic (FRP), glass epoxy resin, cast epoxy resin, polyethylene, vinyl chloride, silicone, fluorine-containing synthetic rubber, nylon, and electrically insulating ceramics.

[0022] Each insulating housing 20 has a first side wall portion 20A, a second side wall portion 20B, a bottom wall portion 20C, and an upper wall portion 20D. In each insulating housing 20, the first side wall portion 20A and the second side wall portion 20B face each other with a gap in the X direction. In each insulating housing 20, the bottom wall portion 20C and the upper wall portion 20D face each other with a gap in the Z direction. One end (lower end) of each of the first side wall portion 20A and the second side wall portion 20B in the Z direction is continuous with the bottom wall portion 20C. The other end (upper end) of each of the first side wall portion 20A and the second side wall portion 20B in the Z direction is continuous with the upper wall portion 20D.

[0023] Each insulating housing 20 defines a space defined by a first side wall 20A, a second side wall 20B, a bottom wall 20C, and an upper wall 20D. Each power conversion unit 10 is disposed within the space of each insulating housing 20. Note that a plurality of power conversion units 10 may be disposed within the space of a single insulating housing 20.

[0024] Each power conversion unit 10 is fixed to a corresponding insulating housing 20. The power conversion unit 10 may be fixed to the insulating housing 20 by any structure, but is fixed to the insulating housing 20 by, for example, adhesive, bolts, or the like.

[0025] The first side surface 10A is spaced apart from the first side wall portion 20A. The second side surface 10B is spaced apart from the second side wall portion 20B. The bottom surface 10C is in contact with the bottom wall portion 20C. The top surface 10D is spaced apart from the upper wall portion 20D. The front surface 10E is, for example, located rearward of the front surfaces of the first side wall portion 20A, the second side wall portion 20B, the bottom wall portion 20C, and the upper wall portion 20D of the insulating housing 20.

[0026] Each of the plurality of power conversion units 10 has a terminal electrically connected to the connection line 140 shown in FIG.

[0027] Hereinafter, power conversion devices 101 to 105 according to first to fifth embodiments will be described as configuration examples of the power conversion device 100 with reference to FIGS.

[0028] 4 and 5, a power conversion device 101 includes a plurality of power conversion units 10, a plurality of insulating housings 20, and a plurality of first connecting members 40. Each of the plurality of power conversion units 10 and the plurality of insulating housings 20 has the basic configuration shown in FIG.

[0029] The plurality of power conversion units 10 include a first power conversion unit 11 and a second power conversion unit 12 adjacent to each other in a first direction DR1.

[0030] The multiple power conversion units 10 further include, for example, a third power conversion unit 13 arranged to overlap the first power conversion unit 11 in a second direction DR2 perpendicular to the first direction DR1, and a fourth power conversion unit 14 adjacent to the second power conversion unit 12 in the first direction DR1.

[0031] In the power conversion device 101, the first direction DR1 is aligned along the X direction, and the second direction DR2 is aligned along the Z direction.

[0032] Each of the multiple power conversion units 10 has at least one terminal 30. The terminal 30 is provided, for example, on the front surface 10E of each power conversion unit 10. The terminal 30 is attached to the front surface 10E, for example, with bolts or adhesive. The terminal 30 may be made of any conductive material, including at least one selected from the group consisting of stainless steel, brass, copper, aluminum, titanium, nickel, iron, gold, platinum, silver, zirconium, Inconel, Hastelloy, molybdenum, and tungsten. The terminal 30 may be configured, for example, as a bus bar or an electric wire. The terminal 30 may have a coating film for improving at least one of voltage resistance, waterproofing, dustproofing, and rust prevention. The terminal 30 may have a coating film made of an electrically insulating material formed by lamination or the like, or a coating film made of a metal material formed by plating or the like.

[0033] The terminal 30 has a first portion 301 extending along the first direction DR1 and a second portion 302 extending along the second direction DR2. The second portion 302 is in contact with, for example, the first side wall portion 20A or the second side wall portion 20B of the insulating housing 20.

[0034] The first power conversion unit 11 has a terminal 31. The second power conversion unit 12 has a terminal 32A and a terminal 32B. The fourth power conversion unit 14 has a terminal 34.

[0035] The insulating housings 20 include a first insulating housing 21 and a second insulating housing 22 adjacent to each other in the first direction DR1.

[0036] The first power conversion unit 11 is disposed in the space of the first insulating housing 21 and is supported by the first insulating housing 21. The first power conversion unit 11 is fixed to the bottom wall portion 20C of the first insulating housing 21. The terminals 30 of the first power conversion unit 11 are disposed in the space of the first insulating housing 21. The terminals 30 of the first power conversion unit 11 do not protrude outside the space of the first insulating housing 21.

[0037] The second power conversion unit 12 is disposed in the space of the second insulating housing 22 and is supported by the second insulating housing 22. The second power conversion unit 12 is fixed to the bottom wall portion 20C of the second insulating housing 22. The terminals 30 of the second power conversion unit 12 are disposed in the space of the second insulating housing 22. The terminals 30 of the second power conversion unit 12 do not protrude outside the space of the second insulating housing 22.

[0038] The first side wall 20A of the first insulating housing 21 faces the second side wall 20B of the second insulating housing 22. The first side wall 20A of the first insulating housing 21 is in contact with, for example, the second side wall 20B of the second insulating housing 22. The first side wall 20A of the first insulating housing 21 and the second side wall 20B of the second insulating housing 22 are disposed between the first power conversion unit 11 and the second power conversion unit 12 in the first direction DR1.

[0039] The top wall 20D of the first insulating housing 21 faces the bottom wall 20C of the third insulating housing 23. The top wall 20D of the first insulating housing 21 is in contact with, for example, the bottom wall 20C of the third insulating housing 23. The top wall 20D of the first insulating housing 21 and the bottom wall 20C of the third insulating housing 23 are disposed between the first power conversion unit 11 and the third power conversion unit 13.

[0040] Each of the multiple first connecting members 40 penetrates one first side wall portion 20A and the other second side wall portion 20B of two adjacent insulating housings 20 in the first direction DR1, connecting them. Each of the multiple first connecting members 40 is composed of a portion penetrating one first side wall portion 20A and the other second side wall portion 20B of two adjacent insulating housings 20 in the first direction DR1, a portion disposed within the space of the one insulating housing, and a portion disposed within the space of the other insulating housing. Each of the multiple first connecting members 40 does not have a portion protruding forward or backward from the space of each insulating housing 20. Each of the multiple first connecting members 40 does not have a bent portion, such as a U-shape. Note that each of the multiple first connecting members 40 may have a bent portion, such as a U-shape. The bent portion of each of the plurality of first connecting members 40 is disposed within the space of one of two adjacent insulating housings 20 in the first direction DR1. Two end portions of each of the plurality of first connecting members 40 located on the opposite side from the bent portion are disposed within the space of the other of the two adjacent insulating housings 20. In such a first connecting member 40, it is sufficient that the two portions disposed within the space of the other of the two adjacent insulating housings 20 are fastened together.

[0041] Each of the plurality of first connecting members 40 may have any structure capable of penetrating one first side wall portion 20A and the other second side wall portion 20B of two adjacent insulating housings 20 in the first direction DR1 and connecting them. Each of the plurality of first connecting members 40 may have a fastening structure including, for example, a bolt and a nut. Each of the plurality of first connecting members 40 may have an adhesive structure using an adhesive.

[0042] The material that constitutes each of the plurality of first connecting members 40 is a conductive material. The plurality of first connecting members 40 are arranged at intervals from one another in, for example, the second direction DR2.

[0043] The multiple first connecting members 40 include multiple first connecting members 41 that penetrate each of the first side wall portion 20A of the first insulating housing 21 and the second side wall portion 20B of the second insulating housing 22 to connect them, and multiple first connecting members 42 that penetrate each of the first side wall portion 20A of the second insulating housing 22 and the second side wall portion 20B of the fourth insulating housing 24 to connect them.

[0044] The terminal 31 of the first power conversion unit 11 and the terminal 32A of the second power conversion unit 12 are electrically and mechanically connected to each of the plurality of first coupling members 41. The terminal 31 of the first power conversion unit 11 and the terminal 32A of the second power conversion unit 12 are electrically connected to each other via each of the plurality of first coupling members 41.

[0045] The terminal 32B of the second power conversion unit 12 and the terminal 34 of the fourth power conversion unit 14 are electrically and mechanically connected to each of the plurality of first coupling members 42. The terminal 32B of the second power conversion unit 12 and the terminal 34 of the fourth power conversion unit 14 are electrically connected to each other via each of the plurality of first coupling members 42. Each of the plurality of first coupling members 41, 42 constitutes a connection line 140 shown in FIG. 1 .

[0046] 3 , the power conversion device 101 further includes a plurality of second coupling members 50. Each of the plurality of second coupling members 50 is provided to mechanically connect two adjacent insulating housings 20 that support two power conversion units 10 that are not electrically connected to each other. Each of the plurality of second coupling members 50 mechanically connects two adjacent insulating housings 20 in the second direction DR2, for example. The material constituting each second coupling member 50 may be a conductive material or an electrically insulating material.

[0047] Fig. 5 shows an example in which each of the plurality of first connecting members 41 has the above-described fastening structure. Each of the first connecting members 41 shown in Fig. 5 has a bolt 411 and a nut 412. The material that makes up the bolt 411 and the nut 412 is a conductive material.

[0048] The second portion 312 of the terminal 31 of the first power conversion unit 11 is in contact with, for example, the first side wall portion 20A of the first insulating housing 21. The second portion 322 of the terminal 32A of the second power conversion unit 12 is in contact with, for example, the second side wall portion 20B of the second insulating housing 22.

[0049] A through hole extending in the first direction DR1 is formed in each of the second portion 312 of the terminal 31, the first side wall portion 20A of the first insulating housing 21, the second side wall portion 20B of the second insulating housing 22, and the second portion 322 of the terminal 32A. The diameter of the through hole is larger than the outer diameter of the bolt 411 and smaller than the outer diameter of the nut 412. The bolt 411 is inserted through the through hole. The nut 412 is fastened to the tip of the bolt 411. The bolt 411 and the nut 412 face the first side surface 10A of the first power conversion unit 11 or the second side surface 10B of the second power conversion unit 12 with a gap therebetween.

[0050] <Effects of Power Conversion Device 101> The effects of the power conversion device 101 will be described based on a comparison with a comparative example 200 shown in FIG.

[0051] 14 , a conductive member 230 protruding to the outside from an opening formed in each of two adjacent insulating housings 220 electrically connects the power conversion units 210 housed in each insulating housing 220. Therefore, in the comparative example, even if a coating film made of an electrically insulating material is formed on the surface of the conductive member 230 by lamination or the like, electric field concentration is likely to occur at the tip of the protruding portion of the conductive member 230, and this portion of the conductive member 230 may become the starting point of discharge, causing a risk of dielectric breakdown.

[0052] Furthermore, in Comparative Example 200, when the connecting member connecting two adjacent insulating housings 220 has a conductive portion made of a conductive material, a floating potential occurs in the connecting member according to the potential difference between the power conversion unit 210 and the surrounding structure. This floating potential can reach several kV or more. In other words, the connecting member, which is electrically floating relative to each power conversion unit 210, is a portion where an electric field is likely to concentrate, and is likely to become a starting point for discharge.

[0053] Furthermore, in the comparative example 200, the conductive member 230 has a bent portion bent into a U-shape, so that the electric field lines are concentrated around the conductive member 230, and the electric field is likely to concentrate on the surface of the conductive member 230.

[0054] In contrast, in the power conversion device 101, the first connecting members 40 do not protrude outside the spaces of the insulating housings 20, and therefore the electric field on the surface of each first connecting member 40 is lower than in the comparative example 200. Therefore, in the power conversion device 101, electric field concentration is less likely to occur in the first connecting members 40 than in the comparative example 200, and the occurrence of dielectric breakdown with each first connecting member 40 as the starting point of discharge can be suppressed.

[0055] Furthermore, in the power conversion device 101, each first connecting member 40 is electrically connected to the terminal 30 of each power conversion unit 10, and therefore each first connecting member 40 is not electrically floating with respect to each power conversion unit 10. Therefore, in the power conversion device 101, the occurrence of dielectric breakdown with each first connecting member 40 as the starting point of discharge can be more effectively suppressed.

[0056] Furthermore, in the power conversion device 101, each first connecting member 41 does not need to have a U-shaped bent portion. The density of electric field lines generated around each first connecting member 41 that does not have a U-shaped bent portion is lower than that of electric field lines generated around the conductive member 230 of the comparative example 200. Therefore, in the power conversion device 101, the occurrence of dielectric breakdown with each first connecting member 40 as the starting point of discharge can be more effectively suppressed.

[0057] <Modifications of the power conversion device 101> The number of each of the power conversion units 10, insulating housings 20, terminals 30, and first connecting members 40 in the power conversion device 101 can be individually set as desired. The power conversion device 101 is required to include at least one first connecting member 40. If the power conversion device 101 is required to have high resistance to vibrations such as earthquakes, the number of each of the first connecting members 40 and second connecting members 50 connecting two adjacent insulating housings 20 may be more than two.

[0058] Preferably, each insulating housing 20 further has a front wall portion and a rear wall portion facing each other with a gap in the Y direction. The front ends of the first side wall portion 20A and the second side wall portion 20B are continuous with the front wall portion. The rear ends of the first side wall portion 20A and the second side wall portion 20B are continuous with the rear wall portion. Since the power conversion device 101 does not require openings for protruding to the outside of the space, each insulating housing 20 can be configured as a container for accommodating each power conversion unit 10. In this case, each insulating housing 20 is configured as a container for accommodating each power conversion unit 10. Preferably, the space defined by the first side wall portion 20A, the second side wall portion 20B, the bottom wall portion 20C, the top wall portion 20D, the front wall portion, and the rear wall portion of each insulating housing 20 may be filled with, for example, an insulating gas.

[0059] In the comparative example 200, the contact point between the conductive member 230 and the insulating housing 220 is a triple junction where air, a conductor, and an insulator come into contact with each other. Therefore, this area is also prone to electric field concentration and to becoming a starting point for discharge. In contrast, in this modified example, the triple junction is not formed, so that the occurrence of dielectric breakdown originating from the triple junction as a starting point for discharge can be suppressed.

[0060] Embodiment 2 Unless otherwise specified, the power conversion device according to embodiment 2 has the same configuration and effects as those of the above-described embodiment 1. Therefore, the same components as those of the above-described embodiment 1 are denoted by the same reference numerals, and description thereof will not be repeated.

[0061] As shown in Figure 6, in the power conversion device 102 of embodiment 2, in the second direction DR2, each first connecting member 40 and each terminal 31, 32A of the first power conversion unit 11 and the second power conversion unit 12 are positioned inside the outer peripheral edges of each of the first power conversion unit 11 and the second power conversion unit 12.

[0062] 6, height H1 indicates the height of the top surface 10D of the first power conversion unit 11 relative to the bottom surface 10C, and height H2 indicates the maximum height of the terminals 31 and the first connecting member 41 relative to the bottom surface 10C. The power conversion device 102 differs from the power conversion device 101 in that the height H2 is limited to be equal to or less than the height H1.

[0063] Similarly, in the power conversion device 102, the maximum height of the terminals 32A and the first connecting member 41 relative to the bottom surface 10C of the second power conversion unit 12 is equal to or less than the height of the top surface 10D relative to the bottom surface 10C of the second power conversion unit 12. The height of the top surface 10D relative to the bottom surface 10C of the second power conversion unit 12 is equal to, for example, the height H1. The maximum height of the terminals 32A and the first connecting member 41 relative to the bottom surface 10C of the second power conversion unit 12 is equal to, for example, the height H2.

[0064] In the second direction DR2, if each first connecting member 40 and each terminal 31, 32A of the first power conversion unit 11 and the second power conversion unit 12 have a portion that is located outside the outer peripheral edge of each of the first power conversion unit 11 and the second power conversion unit 12, there is a risk of insulation breakdown occurring with that portion as the starting point of discharge.

[0065] In the power conversion device 102, in the second direction DR2, each first connecting member 40 and each terminal 31, 32A of the first power conversion unit 11 and the second power conversion unit 12 are disposed inside the outer periphery of each of the first power conversion unit 11 and the second power conversion unit 12. Therefore, in the power conversion device 102, the occurrence of dielectric breakdown with each terminal 31, 32A and each first connecting member 41 as the starting point of discharge can be more effectively suppressed.

[0066] <Modifications of power conversion device 102> The power conversion device 102 can also be modified in the same way as the power conversion device 101. Third embodiment Unless otherwise specified, the power conversion device according to the third embodiment has the same configuration and effects as those of the first embodiment. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof will not be repeated.

[0067] As shown in Figure 7, the power conversion device 103 of embodiment 3 further includes a third connecting member 61 that connects the wall portions of the first insulating housing 21 and the second insulating housing 22 that are adjacent to each other in the first direction DR1.

[0068] The third connecting member 61 has an insulating portion 610. The insulating portion 610 electrically insulates between the terminal 31 of the first power conversion unit 11 and the terminal 32A of the second power conversion unit 12. The material constituting the insulating portion 610 may be any material having electrical insulation properties, and may include, for example, at least one selected from the group consisting of FRP, glass epoxy resin, cast epoxy resin, polyethylene, vinyl chloride, silicone, fluorine-containing synthetic rubber, nylon, and electrically insulating ceramics.

[0069] The insulating portion 610 is disposed, for example, in the space of the second insulating housing 22. The third connecting member 61 further includes, for example, a through-portion 611. The through-portion 611 penetrates the first side wall 20A of the first insulating housing 21 and the second side wall of the second insulating housing 22. The material forming the through-portion 611 may be a conductive material. In this case, the insulating portion 610 mechanically connects the terminal 32A and the through-portion 611 and electrically insulates the terminal 32A of the second power conversion unit 12 from the through-portion 611. The insulating portion 610 may be configured as an insulator, a terminal block, or a joint made of an electrically insulating material.

[0070] In the power conversion device 103, of the first connecting member 41 and the third connecting member 61 that connect the first insulating housing 21 and the second insulating housing 22, only the first connecting member 41 forms a part of the current path between the terminal 31 and the terminal 32A. According to the power conversion device 103, when the number of connecting members that connect the first insulating housing 21 and the second insulating housing 22 is increased, it is possible to prevent the number of main current paths from also increasing.

[0071] <Modifications of the power conversion device 103> The power conversion device 103 may include at least one third connecting member 61. The power conversion device 103 may have a configuration similar to that of the power conversion device 102, except for including at least one third connecting member 61. The power conversion device 103 can be modified in the same manner as the power conversion devices 101 and 102.

[0072] Embodiment 4 Unless otherwise specified, the power conversion device according to embodiment 4 has the same configuration and effects as those of the above-described embodiment 1. Therefore, the same components as those of the above-described embodiment 1 are denoted by the same reference numerals, and the description thereof will not be repeated.

[0073] As shown in FIG. 8 , the power conversion device 104 according to the fourth embodiment further includes a plurality of fixing members 70 for fixing the first power conversion unit 11 to the bottom wall portion 20C of the first insulating casing 21 .

[0074] A first protrusion 20E is formed on the bottom wall 20C of the first insulating housing 21. A first recess 10F is formed on the bottom surface 10C of the first power conversion unit 11. The first protrusion 20E is fitted into the first recess 10F.

[0075] The first recess 10F and the first protrusion 20E have, for example, a rail structure. For example, two protrusions are formed at the lower end of the first power conversion unit 11. The first recess 10F is formed between the two protrusions. The two protrusions extend along the extension direction of the first protrusion 20E. The two protrusions are arranged to sandwich the first protrusion 20E in a direction perpendicular to the extension direction of the first protrusion 20E. The bottom surface 10C of the first power conversion unit 11 is formed by the top surfaces of the two protrusions.

[0076] Each of the multiple fixing members 70 fixes the first recess 10F of the first power conversion unit 11 to the first protrusion 20E of the first insulating housing 21. Each of the multiple fixing members 70 has, for example, a portion that penetrates one of the two protrusions of the first power conversion unit 11 and a portion that screws into the first protrusion 20E. Each fixing member 70 is, for example, a bolt and has a male thread portion. The first protrusion 20E has a female thread portion that screws into the male thread portion of each fixing member 70.

[0077] Each fixing member 70 has, for example, a head 71, a shaft 72, and a tip 73. The head 71 contacts the side surface of one of the two protrusions of the first power conversion unit 11. The shaft 72 passes through one of the two protrusions of the first power conversion unit 11. The tip 73 is connected to the first protrusion 20E. The tip 73 has a male thread. The shaft 72 may also have a male thread.

[0078] Preferably, the head 71 of each fixing member 70 is disposed inward from the outer circumferential edge of the first power conversion unit 11 when viewed from the second direction DR2. The head 71 of each fixing member 70 does not protrude toward the first side wall portion 20A with respect to the first side surface 10A of the first power conversion unit 11.

[0079] The material constituting the fixing members 70 may be a conductive material. In the power conversion device 104, the fixing members 70 for fixing the first power conversion unit 11 to the first insulating housing 21 are arranged inside the first insulating housing 21. Therefore, in the power conversion device 104, electric field concentration is less likely to occur in each fixing member 70 compared to when each fixing member protrudes outside the above-mentioned space of each insulating housing 20, and the occurrence of dielectric breakdown with each fixing member 70 as the starting point of discharge can be suppressed.

[0080] Furthermore, in the power conversion device 104, if the head 71 of each fixing member 70 does not protrude toward the first side wall portion 20A relative to the first side surface 10A of the first power conversion unit 11, electric field concentration at the head 71 of each fixing member 70 can be suppressed.

[0081] <Modification of power conversion device 104> The power conversion device 104 may include at least one fixing member 70. One fixing member 70 may include, for example, a bolt that passes through each of the two protrusions and the first protrusion 20E, and a nut that is fastened to the bolt.

[0082] The power conversion device 104 may have a configuration similar to that of the power conversion device 102 or the power conversion device 103, except that the power conversion device 104 includes at least one fixing member 70. The power conversion device 104 can be modified in the same manner as the power conversion devices 101 to 103.

[0083] Embodiment 5 Unless otherwise specified, the power conversion device according to embodiment 5 has the same configuration and effects as those of embodiment 1. Therefore, the same components as those of embodiment 1 are denoted by the same reference numerals, and the description thereof will not be repeated.

[0084] As shown in FIG. 9 , in the power conversion device 105 according to the fifth embodiment, a second convex portion 20F protruding outward is formed on the top wall portion 20D of the first insulating housing 21. A second concave portion 20G is formed on the bottom wall portion 20C of the third insulating housing 23. The second convex portion 20F is fitted into the second concave portion 20G. The second convex portion 20F and the second concave portion 20G mechanically connect two adjacent insulating housings 20 that support two power conversion units 10 that are not electrically connected to each other. In other words, the second convex portion 20F and the second concave portion 20G function as a second connecting member 50 made of an electrically insulating material. The power conversion device 105 does not include a second connecting member 50 made of a conductive material.

[0085] According to the power conversion device 105, since it does not have a second connecting member 50 that is made of a conductive material and penetrates and connects the first insulating housing 21 and the third insulating housing 23, the occurrence of insulation breakdown caused by the second connecting member 50 can be suppressed.

[0086] <Modification of power conversion device 105> The second convex portion 20F may be provided to be screwed into the second concave portion 20G. The second convex portion 20F may have a male thread portion, and the second concave portion 20G may have a female thread portion.

[0087] 10 , in the power conversion device 105, the third power conversion unit 13 and the third insulating housing 23 may have, for example, the same configuration as the first power conversion unit 11 and the first insulating housing 21, respectively, in the power conversion device 104. The power conversion device 105 further includes, for example, a plurality of fixing members 70.

[0088] The second recess 20G has a protruding portion that protrudes inward from the bottom wall portion 20C of the third insulating housing 23. The protruding portion of the second recess 20G corresponds to the first protruding portion 20E of the power conversion device 104.

[0089] The third power conversion unit 13 has a third recess formed therein that corresponds to the first recess 10F of the power conversion device 104. The protruding portion 20E of the second recess 20G of the third insulating housing 23 is fitted into the third recess 10F of the third power conversion unit 13.

[0090] Each of the multiple fixing members 70 fixes the third recess 10F of the third power conversion unit 13 to the above-mentioned protruding portion 20E of the second recess 20G of the third insulating housing 23, and fixes the second recess 20G of the third insulating housing 23 to the second protruding portion 20F of the first insulating housing 21.

[0091] Each fixing member 70 has, for example, a portion that penetrates the third power conversion unit 13 and the protruding portion 20E of the second recess 20G of the third insulating housing 23, and a portion that screws into the second convex portion 20F of the first insulating housing 21.

[0092] In the power conversion device 105 shown in Figure 10, the fixing member 70 can fix the third power conversion unit 13 to the bottom wall portion 20C of the third insulating housing 23, and can also fix the bottom wall portion 20C of the third insulating housing 23 to the upper wall portion 20D of the first insulating housing 21, so that it has higher resistance to vibration than the power conversion device 105 shown in Figure 9.

[0093] The power conversion device 105 may have the same configuration as any of the power conversion devices 102 to 104, except that a second convex portion 20F is formed on the top wall portion 20D of the first insulating housing 21 and a second concave portion 20G is formed on the bottom wall portion 20C of the third insulating housing 23. The power conversion device 105 can be modified in the same manner as the power conversion devices 101 to 104.

[0094] Embodiment 6 Unless otherwise specified, the power conversion device according to embodiment 6 has the same configuration and effects as those of the above-described embodiment 1. Therefore, the same components as those of the above-described embodiment 1 are denoted by the same reference numerals, and description thereof will not be repeated.

[0095] 11 , in the power conversion device 106 according to the sixth embodiment, the first direction DR1 is along the Z direction, and the second direction DR2 is along the X direction. That is, the terminals 30 of two power conversion units 10 adjacent to each other in the Z direction are electrically connected to each other via at least one first coupling member 40.

[0096] The top wall portion 20D of the first insulating housing 21 faces the bottom wall portion 20C of the second insulating housing 22. The top wall portion 20D of the first insulating housing 21 is in contact with the bottom wall portion 20C of the second insulating housing 22. The top wall portion 20D of the first insulating housing 21 and the bottom wall portion 20C of the second insulating housing 22 are disposed between the first power conversion unit 11 and the second power conversion unit 12 in the first direction DR1.

[0097] The first side wall 20A of the first insulating housing 21 faces the second side wall 20B of the third insulating housing 23. The top wall 20D of the second insulating housing 22 faces the bottom wall 20C of the fourth insulating housing 24.

[0098] The second portion 302 extending along the second direction DR2 in the terminal 30 of each power conversion unit 10 is spaced apart from, for example, the bottom wall portion 20C or the top wall portion 20D of the insulating housing 20.

[0099] The multiple first connecting members 40 include multiple first connecting members 41 that penetrate each of the upper wall portion 20D of the first insulating housing 21 and the bottom wall portion 20C of the second insulating housing 22 to connect them, and multiple first connecting members 42 that penetrate each of the upper wall portion 20D of the second insulating housing 22 and the bottom wall portion 20C of the fourth insulating housing 24 to connect them.

[0100] A plurality of through holes extending in the first direction DR1 are formed in each of the top wall portion 20D of the first insulating housing 21 and the bottom wall portion 20C of the second insulating housing 22. Each of the first connecting members 41 is inserted through each of the through holes.

[0101] The terminal 31 of the first power conversion unit 11 and the terminal 32A of the second power conversion unit 12 are electrically and mechanically connected to each of the plurality of first coupling members 41. The terminal 31 of the first power conversion unit 11 and the terminal 32A of the second power conversion unit 12 are electrically connected to each other via each of the plurality of first coupling members 41.

[0102] The terminal 32B of the second power conversion unit 12 and the terminal 34 of the fourth power conversion unit 14 are electrically and mechanically connected to each of the plurality of first coupling members 42. The terminal 32B of the second power conversion unit 12 and the terminal 34 of the fourth power conversion unit 14 are electrically connected to each other via each of the plurality of first coupling members 42.

[0103] In the power conversion device 106 as well, the structure of each of the plurality of first connecting members 41 is not particularly limited.

[0104] FIG. 12 shows an example of a power converter 106 in which each of the plurality of first connecting members 41 has the above-described fastening structure.

[0105] Each first connecting member 41 has, for example, a shaft portion 413 having a male thread portion and a female thread portion 414 .

[0106] The shaft portion 413 has, for example, a third portion 413A and two fourth portions 413B. The third portion 413A is inserted through the through-hole formed in each of the top wall portion 20D of the first insulating housing 21 and the bottom wall portion 20C of the second insulating housing 22, and through-holes formed in each of the second portion 312 of the terminal 31 and the second portion 322 of the terminal 32A. Each of the two fourth portions 413B protrudes outward from the through-hole formed in each of the second portion 312 of the terminal 31 and the second portion 322 of the terminal 32A. One of the two fourth portions 413B is connected to the lower end of the third portion 413A. The other of the two fourth portions 413B is connected to the upper end of the third portion 413A. Each of the two fourth portions 413B is formed as a male thread portion that screws into the female thread portion 414.

[0107] The first connecting member 41 can keep the relative positions of the first insulating casing 21 and the second insulating casing 22 constant.

[0108] 11 , each first coupling member 40 and a portion of each terminal 31, 32A of the first power conversion unit 11 and the second power conversion unit 12 may be disposed outside the first side surface 10A and the second side surface 10B of each of the first power conversion unit 11 and the second power conversion unit 12 when viewed from the Y direction. Preferably, as shown in FIG. 12 , each first coupling member 40 and each terminal 31, 32A of the first power conversion unit 11 and the second power conversion unit 12 are disposed entirely inside the outer periphery of each of the first power conversion unit 11 and the second power conversion unit 12 when viewed from the Y direction. According to this power conversion device 106, similar to the power conversion device 102 according to the second embodiment, it is possible to more effectively suppress the occurrence of dielectric breakdown originating from each terminal 31, 32A and each first coupling member 41 as a discharge starting point.

[0109] The through holes formed in each of the first side wall portion 20A of the first insulating housing 21 and the second side wall portion 20B of the second insulating housing 22 may be formed as female thread portions. The third portion 413A of the shaft portion 413 may be provided so as to threadably engage with the female thread portions formed in each of the first side wall portion 20A of the first insulating housing 21 and the second side wall portion 20B of the second insulating housing 22.

[0110] <Modifications of power conversion device 106> The power conversion device 106 may have the same configuration as any of the power conversion devices 102 to 105, except that the first direction DR1 is along the Z direction and the second direction DR2 is along the X direction. The power conversion device 106 can be modified in the same manner as the power conversion devices 101 to 105.

[0111] Embodiment 7 Unless otherwise specified, the power conversion device according to embodiment 7 has the same configuration and effects as those of the above-described embodiment 6. Therefore, the same components as those of the above-described embodiment 6 are denoted by the same reference numerals, and description thereof will not be repeated.

[0112] 13 , in a power conversion device 107 according to the seventh embodiment, a fourth recess 20H is formed in the first side wall 20A of the first insulating housing 21. A third protrusion 20I is formed in the second side wall 20B of the third insulating housing 23. The third protrusion 20I is fitted into the fourth recess 20H.

[0113] The third convex portion 20I is provided to screw into, for example, the fourth recess 20H. The third convex portion 20I has a male thread portion. The fourth recess 20H has a female thread portion. The third convex portion 20I and the fourth recess 20H mechanically connect two adjacent insulating housings 20 that support two power conversion units 10 that are not electrically connected to each other. In other words, the third convex portion 20I and the fourth recess 20H act as a second connecting member 50 made of an electrically insulating material. The power conversion device 107 does not have a second connecting member 50 made of a conductive material.

[0114] According to the power conversion device 107, since it does not have a second connecting member 50 that is made of a conductive material and penetrates and connects the first insulating housing 21 and the third insulating housing 23, the occurrence of insulation breakdown caused by the second connecting member 50 can be suppressed.

[0115] <Modification of power conversion device 107> The third convex portion 20I may be formed on either the first side wall portion 20A of the first insulating housing 21 or the second side wall portion 20B of the third insulating housing 23. The fourth concave portion 20H may be formed on the other of the first side wall portion 20A of the first insulating housing 21 or the second side wall portion 20B of the third insulating housing 23.

[0116] The power converter 107 may have the same configuration as any of the power converters 102 to 105, except that the first direction DR1 is along the Z direction and the second direction DR2 is along the X direction. The power converter 107 can be modified in the same manner as the power converters 101 to 105.

[0117] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, and it is intended to include all modifications within the meaning and scope of the claims.

[0118] 1a, 1b Switching elements, 2a, 2b Diodes, 3 Capacitors, 4a, 4b, 140 Connecting wires, 10 Power conversion unit, 10A First side surface, 10B Second side surface, 10C Bottom surface, 10D Top surface, 10E Front surface, 10F First recess, Third recess, 11 First power conversion unit, 12 Second power conversion unit, 13 Third power conversion unit, 14 Fourth power conversion unit, 20 Insulating housing, 20A First side wall portion, 20B Second side wall portion, 20C Bottom wall portion, 20D Top wall portion, 20E First convex portion, Protruding portion, 20F Second convex portion, 20G Second recess, 20H Fourth recess, 20I Third convex portion, 21 First insulating housing, 22 Second insulating housing, 23 Third insulating housing, 24 Fourth insulating housing, 30, 31, 32A, 32B, 34 Terminal, 40, 41, 42 First connecting member, 50 Second connecting member, 61 Third connecting member, 70 Fixing member, 71 Head, 72 Shaft portion, 73 Tip portion, 100, 101, 102, 103, 104, 105, 106, 107 Power conversion device, 110 Upper arm, 120 Lower arm, 130 Transformer, 301 First portion, 302, 312, 322 Second portion, 411 Bolt, 412 Nut, 413 Shaft portion, 413A Third portion, 413B Fourth portion, 413C Fifth portion, 414 Female thread portion, 610 Insulating portion, 611 Penetrating portion.

Claims

1. A power conversion device comprising: a plurality of power conversion units having a first power conversion unit and a second power conversion unit adjacent to each other in a first direction; and a plurality of insulating housings having a first insulating housing and a second insulating housing adjacent to each other in the first direction, wherein the first power conversion unit is supported by the first insulating housing, and the second power conversion unit is supported by the second insulating housing, each of the first power conversion unit and the second power conversion unit has a terminal, each of the first insulating housing and the second insulating housing has a wall portion disposed between the first power conversion unit and the second power conversion unit in the first direction, and further comprising at least one first connecting member penetrating and connecting the wall portions of the first insulating housing and the second insulating housing, and the terminals of each of the first power conversion unit and the second power conversion unit are electrically connected to each other via the at least one first connecting member.

2. The power conversion device described in claim 1, wherein each of the multiple insulating housings has a first side wall portion and a second side wall portion facing each other with a gap in the first direction, and a bottom wall portion and a top wall portion facing each other with a gap in a second direction perpendicular to the first direction, each of the multiple insulating housings has a space defined by the first side wall portion, the second side wall portion, the bottom wall portion and the top wall portion, each of the multiple insulating housings is disposed within the space of each of the multiple insulating housings, the wall portion of the first insulating housing is the first side wall portion of the first insulating housing, and the wall portion of the second insulating housing is the second side wall portion of the second insulating housing adjacent to the first side wall portion of the first insulating housing in the first direction.

3. A power conversion device as described in claim 2, wherein a first convex portion is formed on the bottom wall portion of the first insulating housing, a first concave portion is formed on the first power conversion unit, the first concave portion is fitted with the first convex portion, and the power conversion device further comprises at least one fixing member that fixes the first concave portion of the first power conversion unit to the first convex portion of the first insulating housing.

4. The power conversion device according to claim 2, wherein the plurality of power conversion units further includes a third power conversion unit adjacent to the first power conversion unit in the second direction, the plurality of insulating housings further includes a third insulating housing adjacent to the first insulating housing in the second direction, a space is formed in the third insulating housing defined by the first side wall portion, the second side wall portion, the bottom wall portion and the top wall portion, the third power conversion unit is disposed in the space of the third insulating housing, the bottom wall portion of the third insulating housing is in contact with the top wall portion of the first insulating housing, a second convex portion protruding outward is formed on the top wall portion of the first insulating housing, and a second concave portion mated with the second convex portion is formed on the bottom wall portion of the third insulating housing.

5. A power conversion device as described in claim 4, wherein the second recess has a protruding portion that protrudes inward further than the bottom wall portion of the third insulating housing, the third power conversion unit is formed with a third recess that fits with the protruding portion, and the power conversion device further comprises at least one fixing member that fixes the third recess of the third power conversion unit to the protruding portion of the second recess of the third insulating housing and fixes the second recess of the third insulating housing to the second convex portion of the first insulating housing.

6. A power conversion device as described in any one of claims 2 to 5, wherein in the second direction, the at least one first connecting member and the terminals of each of the first power conversion unit and the second power conversion unit are positioned inside the outer circumferential edges of each of the first power conversion unit and the second power conversion unit.

7. The power conversion device described in claim 1, wherein each of the multiple insulating housings has a first side wall portion and a second side wall portion facing each other with a gap therebetween, a bottom wall portion connected to lower ends of the first side wall portion and the second side wall portion, and an upper wall portion connected to upper ends of the first side wall portion and the second side wall portion, each of the multiple insulating housings has a space defined by the first side wall portion, the second side wall portion, the bottom wall portion and the upper wall portion, each of the multiple power conversion units is disposed in the space of each of the multiple insulating housings, the wall portion of the first insulating housing is the upper wall portion of the first insulating housing, and the wall portion of the second insulating housing is the bottom wall portion of the second insulating housing adjacent to the upper wall portion of the first insulating housing in the first direction.

8. The power conversion device according to claim 7, wherein the plurality of power conversion units further includes a third power conversion unit adjacent to the first power conversion unit in a second direction perpendicular to the first direction, the plurality of insulating housings further includes a third insulating housing adjacent to the first insulating housing in the second direction, a space is formed in the third insulating housing defined by the first side wall portion, the second side wall portion, the bottom wall portion and the top wall portion, the third power conversion unit is disposed in the space of the third insulating housing, the second side wall portion of the third insulating housing is in contact with the first side wall portion of the first insulating housing, a third convex portion is formed on one of the first side wall portion of the first insulating housing and the second side wall portion of the third insulating housing, and a fourth concave portion into which the third convex portion is fitted is formed on the other of the first side wall portion of the first insulating housing and the second side wall portion of the third insulating housing.

9. A power conversion device as described in any one of claims 1 to 8, further comprising at least one third connecting member connecting the wall portions of the first insulating housing and the second insulating housing, the at least one third connecting member having an insulating portion that electrically insulates between the terminal of the first power conversion unit and the terminal of the second power conversion unit.

Images