Power conversion device

Abstract

To provide a power conversion device capable of suppressing local heat generation even when a skin effect occurs in an AC bus bar.SOLUTION: A power conversion device that converts DC power into AC power includes a plurality of semiconductor modules, and an AC busbar that is commonly connected to output terminals of the plurality of semiconductor modules, in which the AC busbar has a multilayer structure divided into a plurality of parts in a thickness direction, and includes an insulating layer that is partially provided between an upper plate that is an upper side and a lower plate that is a lower side.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a power conversion device, and more particularly to a power conversion device in which three semiconductor modules are connected in parallel. [Background technology]

[0002] Half-bridge modules, which consist of two insulated gate bipolar transistors (IGBTs) connected in series, are used as basic units for converters and inverters, and multiple units may be connected in parallel to increase output power.

[0003] For example, Patent Document 1 discloses a configuration in which three half-bridge modules are connected in parallel to output AC currents of U phase, V phase, and W phase. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2024 / 048066 Summary of the Invention [Problem to be solved by the invention]

[0005] When DC current is converted to AC current using a half-bridge module in which IGBTs are connected in series, the high-speed switching operation of the IGBTs generates AC current with a superimposed high frequency, which causes a skin effect and causes localized heat generation on the surface of the AC bus bar, which serves as the output section, requiring thermal countermeasures. However, Patent Document 1 does not specifically disclose the problems associated with AC current with a superimposed high frequency.

[0006] The present disclosure has been made to solve the above-described problems, and aims to provide a power conversion device that can suppress localized heat generation even when the skin effect occurs in an AC bus bar. [Means for solving the problem]

[0007] The power conversion device according to the present disclosure is a power conversion device that converts DC power into AC power, and includes a plurality of semiconductor modules and an AC bus bar commonly connected to output terminals of the plurality of semiconductor modules, the AC bus bar having a multi-layer structure divided into a plurality of parts in the thickness direction, and an insulating layer partially provided between an upper plate that is an upper side and a lower plate that is a lower side. [Effects of the Invention]

[0008] According to the power conversion device of the present disclosure, an insulating layer is partially provided between the upper plate, which is the upper side, and the lower plate, which is the lower side. Therefore, by increasing the current paths for AC current, it is possible to reduce the influence of the skin effect in a pseudo manner, and it is possible to obtain a power conversion device that suppresses localized heat generation in the AC bus bar. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing the configuration of a power stack in which three semiconductor modules are connected in parallel. [Figure 2] FIG. 1 is a circuit diagram illustrating a typical three-phase AC inverter. [Figure 3] FIG. 2 is a waveform diagram showing an AC current on which a high frequency wave is superimposed. [Figure 4] 1 is a perspective view illustrating a configuration of an AC bus bar according to a first embodiment of the present disclosure. [Figure 5] FIG. 2 is an exploded perspective view of the AC bus bar according to the first embodiment of the present disclosure. [Figure 6] FIG. 1 illustrates the concept of skin effect. [Figure 7] FIG. 10 is an exploded perspective view of an AC bus bar according to a first modification of the first embodiment of the present disclosure. [Figure 8] FIG. 10 is an exploded perspective view of an AC bus bar according to a second modification of the first embodiment of the present disclosure. [Figure 9] FIG. 10 is an exploded perspective view of an AC bus bar according to a third modification of the first embodiment of the present disclosure. [Figure 10]FIG. 10 is a perspective view illustrating a configuration of an AC bus bar according to a second embodiment of the present disclosure. [Figure 11] FIG. 10 is a diagram schematically illustrating a current flow in an AC bus bar according to a second embodiment of the present disclosure. [Figure 12] FIG. 11 is a perspective view illustrating a configuration of an AC bus bar according to a third embodiment of the present disclosure. [Figure 13] FIG. 11 is a perspective view illustrating a configuration of an AC bus bar according to a third embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] <Introduction> Fig. 1 is a perspective view showing the configuration of a power stack PST in which three semiconductor modules SM are connected in parallel. As shown in Fig. 1, the power stack 1000 includes a housing BX that houses multiple smoothing capacitors SC, a DC bus bar DCB mounted on top of the housing BX, three semiconductor modules SM connected to the DC bus bar DCB, and an AC bus bar ACB commonly connected to the output terminals of the three semiconductor modules SM. The power stack PST is also provided with a cooling fan and input / output units for a cooling medium, but these are not particularly relevant to this disclosure and will not be described here.

[0011] FIG. 2 is a circuit diagram illustrating a typical three-phase AC inverter. As shown in FIG. 2, IGBT Q1 and IGBT Q2 are connected in series between a main power supply line PL on the high potential side (P side) and a main power supply line NL on the low potential side (N side) to form a half-bridge module. Diodes D1 and D2 are connected in antiparallel to IGBT Q1 and IGBT Q2, respectively. The connection node between IGBT Q1 and IGBT Q2 forms a U terminal that outputs the U phase and is connected to an inductive load L such as a motor. Note that FIG. 2 also shows half-bridge modules that output the V phase and W phase, but their description will be omitted.

[0012] To obtain a three-phase AC inverter as shown in Fig. 2, three power stack PSTs as shown in Fig. 1 are required. In other words, the power stack PST in Fig. 1 corresponds to one phase of a half-bridge module.

[0013] As explained above, when DC current is converted to AC current using a half-bridge module in which IGBTs are connected in series, AC current with a superimposed high frequency is generated due to the inverter's high-speed switching frequency, which reaches several tens of kHz. Figure 3 is a waveform diagram showing AC current with a superimposed high frequency.

[0014] In Figure 3, the horizontal axis represents time [ms] and the vertical axis represents current [A]. As shown in Figure 3, high frequencies are superimposed on the AC waveforms of the U, V, and W phases, which have a frequency of about 100 Hz, and the waveforms are not smooth. When AC current with such high frequencies superimposed on it flows through a conductor, a skin effect occurs, in which current flows only on the surface of the conductor, causing localized heat generation.

[0015] In addition, in the following description, terms that indicate specific positions and directions, such as "top," "bottom," "side," "front," and "back," may be used. However, these terms are used for convenience to facilitate understanding of the contents of the embodiments, and are not related to the directions in which the embodiments are actually implemented.

[0016] Furthermore, the drawings are schematic, and the relative sizes and positions of images shown in different drawings are not necessarily accurately depicted and may be changed as appropriate. In the following description, similar components are denoted by the same reference numerals, and their names and functions are also the same. Therefore, detailed descriptions thereof may be omitted.

[0017] Hereinafter, in an embodiment according to the present disclosure, an AC bus bar that suppresses local heat generation will be described.

[0018] <First Embodiment> FIG. 4 is a perspective view showing a configuration of an AC busbar 100 according to a first embodiment of the present disclosure. The AC busbar 100 shown in FIG. 4 corresponds to the AC busbar ACB of the power stack PST described with reference to FIG. 1 and is commonly connected to output terminals (not shown) of the three semiconductor modules SM shown in FIG. 1. Although the semiconductor modules are not shown below for convenience, they are fastened to the output terminals of the respective semiconductor modules via a plurality of fastening holes IBH (first through holes) that serve as input portions provided on one long side of the portion of the AC busbar 100 that corresponds to the head of the T-shape in a plan view. In this example, three fastening holes IBH are arranged in a row for one semiconductor module, for a total of nine fastening holes IBH, but the number of fastening holes IBH is not limited to this. Fastening to the output terminals is performed using bolts or nuts.

[0019] At the end of the part corresponding to the leg of the T on the opposite side from the fastening holes IBH, a plurality of fastening holes OBH are provided as output parts for connecting to external wiring (not shown). In this example, four fastening holes OBH (second through holes) are provided, but the number of fastening holes OBH is not limited to this. Note that fastening to external wiring is performed using bolts or nuts.

[0020] The AC busbar 100 is constructed by stacking an upper plate 101 (first conductor plate) and a lower plate 102 (second conductor plate) made of a highly conductive material such as copper, and Figure 5 shows the two plates separated.

[0021] As shown in FIG. 5 , an insulator IS (insulating layer) is interposed between the upper plate 101 and the lower plate 102, which have a T-shaped planar shape. The insulator IS, like the upper plate 101 and the lower plate 102, has a T-shaped planar shape, but is sized and shaped so as not to cover the arrangement of the fastening holes IBH and the fastening holes OBH. The insulator IS may be, for example, an insulating sheet having a thickness of 0.5 mm, such as Nomex® paper. Alternatively, a liquid insulating material such as Humiseal®, which is used for insulating coatings on electronic circuit boards, may be applied to the insulator IS. The thickness of the insulator IS is not limited to 0.5 mm; it may be thinner as long as it can provide electrical insulation between the upper plate 101 and the lower plate 102.

[0022] When the upper plate 101 and the lower plate 102 are fastened together via the fastening holes IBH, the input portion of the upper plate 101 is electrically connected to the input portion of the lower plate 102. When the upper plate 101 and the lower plate 102 are fastened together via the fastening holes OBH, the output portion of the upper plate 101 is electrically connected to the output portion of the lower plate 102.

[0023] When assembling AC bus bar 100, insulator IS is placed or applied and dried on lower plate 102, and then upper plate 101 is placed on top of lower plate 102, whereby AC bus bar 100 can be obtained.

[0024] By inserting an insulator IS between the upper plate 101 and the lower plate 102, the upper plate 101 and the lower plate 102 are insulated in the area where the insulator IS is provided, and current flows separately between the upper plate 101 and the lower plate 102.

[0025] That is, the current flowing through the AC busbar 100 flows as follows. First, the current is input from the output terminal of the semiconductor module to the input section, which electrically connects the upper plate 101 and the lower plate 102. The current input from the input section is divided into a current flowing toward the output section via the upper plate 101 and a current flowing toward the output section via the lower plate 102 in the area where the insulator IS is provided. Here, in the area where the insulator IS is provided, the current flowing through the upper plate 101 and the current flowing through the lower plate 102 are in the same direction. Furthermore, the output section is electrically connected to the upper plate 101, and the current flowing through the upper plate 101 and the current flowing through the lower plate 102 join at the output section and flow to the external wiring. That is, the current flowing through the AC busbar 100 is input from the input section to the AC busbar 100, divided into a current flowing from the input section to the output section via the upper plate 101 and a current flowing from the input section to the output section via the lower plate 102, which join at the output section and are then output to the external wiring.

[0026] As explained above, when an AC current with a superimposed high frequency wave flows through a conductor, it generates a skin effect, in which the current flows only on the surface of the conductor. Fig. 6 is a diagram illustrating the concept of the skin effect. Fig. 6 is a partial cross section of the AC busbar 100 on line AA shown in Fig. 4, and schematically illustrates the portion where the insulator IS is provided between the upper plate 101 and the lower plate 102.

[0027] As shown in Figure 6, due to the presence of the insulator IS, the current IC flows separately between the upper plate 101 and the lower plate 102, and furthermore, it flows only on the top and bottom surfaces of the upper plate 101 and the lower plate 102, and does not flow in the central part sandwiched between the dashed lines. This is the skin effect. The skin depth for copper material is 0.65 mm at a frequency of 10 kHz, and becomes thinner as the frequency increases.

[0028] The region through which the current IC shown in FIG. 6 flows is the region defined by the skin depth. If the thickness of each of the upper plate 101 and the lower plate 102 is, for example, 6 mm, at a frequency of 10 kHz, the current IC will flow only in a region that is about 1 / 10 of the thickness.

[0029] If the insulator IS is not provided and the AC bus bar 100 is configured as a single plate, current flows only on the upper and lower surfaces of the single plate, resulting in high electrical resistance and current concentration.

[0030] However, by providing the insulator IS as shown in FIG. 6, the area of ​​the current path is doubled, the influence of the skin effect can be reduced in a pseudo manner, and the concentration of current inside the AC bus bar 100 can be reduced.

[0031] Although AC busbar 100 is made up of two overlapping plates, upper plate 101 and lower plate 102, the number of overlapping plates is not limited to two, but can be four, and if an insulator IS is inserted between each plate, the area of ​​the current path will be four times larger. The number of overlapping plates can be further increased.

[0032] If the thickness of each of upper plate 101 and lower plate 102 is, for example, 6 mm, the thickness of AC bus bar 100 will be approximately 12 mm. This is to keep the temperature change of the bus bar at 40°C or less, and if the thickness is about 10 to 15 mm, the temperature change of the bus bar can be kept at 40°C or less.

[0033] <Variation 1> Fig. 7 is an exploded perspective view showing the configuration of AC busbar 100A according to Variation 1 of Embodiment 1, and corresponds to the state in which upper plate 101 and lower plate 102 are separated as shown in Fig. 5. In Fig. 7, the same components as those in AC busbar 100 described using Fig. 5 are denoted by the same reference numerals, and redundant description will be omitted.

[0034] As shown in FIG. 7 , the AC bus bar 100A has a spacer SP1 (first spacer) and a spacer SP2 (second spacer) interposed between the upper plate 101 and the lower plate 102 in addition to the insulator IS. The spacers SP1 and SP2 are provided in an area where the insulator IS is not provided. The spacer SP1 is arranged in an area where nine fastening holes IBH are provided, has a long and narrow rectangular shape in a plan view, and has nine through holes ITH (third through holes) aligned with the fastening holes IBH. The spacer SP2 is arranged in an area where four fastening holes OBH are provided, has a rectangular shape in a plan view, and has four through holes OTH (fourth through holes) aligned with the fastening holes OBH.

[0035] The spacers SP1 and SP2 are formed of a conductor, for example, 0.5 mm thick. The same copper material as the busbars can be used, but any conductor is acceptable as long as galvanic corrosion is not an issue. Materials with high conductivity are preferable in terms of heat generation. The thickness is set to 0.5 mm to match the thickness of the insulator IS, but it can also be thinner than the insulator IS. The thinner the spacers SP1 and SP2, the more desirable the resistance component of the spacers can be reduced.

[0036] Furthermore, the inner surfaces of the through holes ITH and OTH of the spacers SP1 and SP2 can be made into insulating films by forming an oxide film or the like.

[0037] By inserting spacers SP1 and SP2 between the upper plate 101 and the lower plate 102, no gaps are created between the upper plate 101 and the lower plate 102 in the fastening area where fastening holes IBH and OBH are provided. For example, when fastening to the output terminal of a semiconductor module, the upper plate 101 and the lower plate 102 can be fastened without any gaps, thereby reducing contact resistance and decreasing the resistance component.

[0038] <Variation 2> Fig. 8 is an exploded perspective view showing the configuration of AC busbar 100B according to Modification 2 of Embodiment 1, and corresponds to the state in which upper plate 101 and lower plate 102 are separated as shown in Fig. 5. In Fig. 8, the same components as those in AC busbar 100A described using Fig. 7 are denoted by the same reference numerals, and redundant description will be omitted.

[0039] 8, the AC bus bar 100B does not have an insulator IS between the upper plate 101 and the lower plate 102, and only spacers SP1 and SP2 are inserted between them. The positions of the spacers SP1 and SP2 are the same as those of the AC bus bar 100A.

[0040] By providing only spacers SP1 and SP2 between the upper plate 101 and the lower plate 102, a gap, i.e., an air layer that serves as an insulating layer, exists in the area where the spacers SP1 and SP2 are not provided, i.e., the area where the insulator IS was provided, and current flows separately between the upper plate 101 and the lower plate 102, just as in the case where the insulator IS is provided. The area of ​​the current path is doubled, which effectively reduces the influence of the skin effect and reduces current concentration within the AC bus bar 100B.

[0041] Furthermore, since no insulator IS is provided, manufacturing costs can be reduced and assembly is easy.

[0042] <Variation 3> Fig. 9 is an exploded perspective view showing the configuration of AC busbar 100C according to Modification 3 of Embodiment 1, and corresponds to the state in which upper plate 101 and lower plate 102 are separated as shown in Fig. 5. Note that in Fig. 8, the same components as those in AC busbar 100 described using Fig. 5 are denoted by the same reference numerals, and redundant description will be omitted.

[0043] As shown in FIG. 9, the AC bus bar 100C has neither an insulator IS nor spacers SP1 and SP2 between the upper plate 101 and the lower plate 102, and the region of the lower plate 102 where the insulator IS was provided becomes a recess DP.

[0044] By providing the recess DP, a gap, i.e., air acting as an insulating layer, is formed between the upper plate 101 and the lower plate 102, and similarly to the case where the insulator IS is provided, the current flows separately between the upper plate 101 and the lower plate 102. The area of ​​the current path is doubled, which can effectively reduce the influence of the skin effect and reduce current concentration within the AC bus bar 100C.

[0045] By providing the recess DP in the lower plate 102, the upper plate 101 and the lower plate 102 have different shapes.

[0046] The recess DP can also be provided on the surface of the upper plate 101 facing the lower plate 102, in which case the upper plate 101 and the lower plate 102 will have the same shape. By making the upper plate 101 and the lower plate 102 have the same shape, it is no longer necessary to produce them separately, which reduces manufacturing costs and avoids the risk of mixing up the upper plate 101 and the lower plate 102 during assembly.

[0047] When the recess DP is provided in the lower plate 102, the depth of the recess DP can be, for example, 0.5 mm, but if the same recess is also provided on the surface of the upper plate 101 facing the lower plate 102, the depths of the recesses can be set so that a gap of 0.5 mm is formed in total. The width of the gap created by the recesses is not limited to 0.5 mm.

[0048] Furthermore, since the insulator IS and the spacers SP1 and SP2 are not provided, the manufacturing cost can be reduced and assembly is also facilitated.

[0049] <Embodiment 2> Fig. 10 is a perspective view showing the configuration of an AC busbar 200 according to a second embodiment of the present disclosure. The AC busbar 200 shown in Fig. 10 differs from the AC busbar 100 described with reference to Fig. 4 in that a notch portion NP having an elongated shape in a plan view is provided in the center of the portion corresponding to the head of the T and parallel to the arrangement of the fastening holes IBH. Note that in Fig. 10, the same components as those in the AC busbar 100 described with reference to Fig. 4 are denoted by the same reference numerals, and redundant description will be omitted.

[0050] The cutout portion NP is provided so as to penetrate the upper plate 201 and the lower plate 202, but when an insulator IS is interposed between the upper plate 201 and the lower plate 202 as in Fig. 5, the insulator IS is exposed in the cutout portion NP as shown in Fig. 10. Note that when the insulator IS is not provided as shown in Figs. 8 and 9, the cutout portion NP becomes a through hole that penetrates the upper plate 201 and the lower plate 202.

[0051] By providing the notched portion NP, it is possible to balance the current flowing from the output terminal of the semiconductor module SM (FIG. 1) of the power stack PST (FIG. 1).

[0052] Fig. 11 is a diagram schematically illustrating the flow of current when current flows into AC bus bar 200 through nine fastening holes IBH. Fig. 11 illustrates the ratio of current I1 flowing through AC bus bar 200, assuming that current I1 flows through three fastening holes IBH connected to one semiconductor module SM.

[0053] As shown in Figure 11, the current I1 that flows into the three central fastening holes IBH is split into currents of 0.5I1 each to the left and right. The current I1 that flows into each of the three left and right fastening holes IBH joins with the split 0.5I1 to become 1.5I1 each, which then join at the parts that correspond to the legs of the T to become 3I1 and flow into the four fastening holes OBH at the ends of the legs.

[0054] 11 shows the current flow in the upper plate 101, but the same current flows in the lower plate 102. Current flows in the same direction in the upper plate 101 and the lower plate 102, thereby maintaining current balance.

[0055] In this way, by providing the cutout portion NP, the current output from the three semiconductor modules SM flows evenly within the bus bar in a planar view, further suppressing current concentration and reducing localized heat generation within the bus bar.

[0056] The longitudinal length of the notch portion NP is at least longer than the arrangement length of the central three fastening holes IBH, and the longitudinal length of the notch portion NP is at least approximately the diameter of the fastening holes IBH.

[0057] <Third Embodiment> Fig. 12 is a perspective view showing a configuration of an AC busbar 300 according to a third embodiment of the present disclosure. In Fig. 12, the same components as those of the AC busbar 200 described with reference to Fig. 10 are denoted by the same reference numerals, and redundant description will be omitted.

[0058] The cutout portion NP is provided so as to penetrate the upper plate 301 and the lower plate 302, but when an insulator IS is interposed between the upper plate 301 and the lower plate 302 as in Fig. 5, the insulator IS is exposed in the cutout portion NP as shown in Fig. 12. Note that when the insulator IS is not provided as shown in Figs. 8 and 9, the cutout portion NP becomes a through hole that penetrates the upper plate 301 and the lower plate 302.

[0059] 12 differs from AC busbar 200 described with reference to FIG. 10 in that notch NP is provided not in the center of the T-shaped head but in a position closer to the arrangement of fastening holes IBH.

[0060] That is, of the two long sides of the cutout portion NP, the length B from the edge of the first long side on the fastening hole IBH side to the edge of the AC busbar 200 on the fastening hole IBH side is shorter than the length A from the edge of the second long side on the fastening hole IBH side to the edge of the AC busbar 200 on the opposite side from the fastening hole IBH.

[0061] The optimum ratio of length A to length B varies depending on the number of parallel semiconductor modules SM (FIG. 1) connected to AC bus bar 300. That is, although three semiconductor modules SM are connected in parallel in FIG. 12, any number of semiconductor modules can be connected without being limited to three. In the case of three parallel semiconductor modules, for example, A:B=3:2 can be used.

[0062] The length B is set to a length that allows fastening members such as bolts, nuts, and washers to be in sufficient contact with the bus bars for fastening to the semiconductor module SM.

[0063] The current path through which current flows in a planar view is the same as that of the AC busbar 200 described using Figure 11, and by providing the cutout portions NP, the current output from the three semiconductor modules SM flows evenly within the busbar in a planar view, further suppressing current concentration and reducing localized heat generation within the busbar.

[0064] <Fourth Embodiment> Fig. 13 is a perspective view showing the configuration of AC busbar 400 according to a second embodiment of the present disclosure. Similar to AC busbar 200 described with reference to Fig. 10, AC busbar 400 shown in Fig. 13 has a configuration in which a notch portion NP having an elongated shape in a plan view is provided in the center of a portion corresponding to the head of the T and parallel to the arrangement of fastening holes IBH. Note that in Fig. 13, the same components as those in AC busbar 200 described with reference to Fig. 10 are denoted by the same reference numerals, and redundant description will be omitted.

[0065] The cutout portion NP is provided so as to penetrate the upper plate 401 and the lower plate 402, but when an insulator IS is interposed between the upper plate 401 and the lower plate 402 as in Fig. 5, the insulator IS is exposed in the cutout portion NP as shown in Fig. 13. Note that when the insulator IS is not provided as shown in Figs. 8 and 9, the cutout portion NP becomes a through hole that penetrates the upper plate 401 and the lower plate 402.

[0066] As shown in FIG. 13, AC bus bar 400 has two fastening holes OBH for connecting output wiring (not shown), which are not arranged in a row horizontally or vertically in a plan view, but are arranged at an angle oblique to the short side of the T-shaped leg.

[0067] By reducing the number of fastening holes OBH from four to two, the current carrying area can be increased and the concentration of current density can be reduced compared to when there are four holes.

[0068] That is, fastening holes IBH and OBH use fastening members such as bolts, nuts, and washers to fasten the semiconductor module SM (Fig. 1) and output wiring, but these are made of materials with higher resistance components than the busbars. For example, stainless steel, which has higher strength, is used for busbars made of copper. For this reason, increasing the number of fastening holes and fastening members improves the fastening force, but also increases the number of points where electricity flows through fastening members with high resistance, creating a trade-off in that the resistance component increases.

[0069] Regarding the fastening holes IBH, it is difficult to arbitrarily reduce the number due to the current inflow from the semiconductor module SM, but regarding the fastening holes OBH, by reducing the number, it is possible to reduce the number of fastening members and reduce the resistance component.

[0070] Furthermore, by providing the fastening holes OBH at an angle in plan view, the fastening force to the output wiring can be improved compared to when the fastening holes OBH are provided in a single horizontal or vertical row.

[0071] <Example of application to power stack> By applying the AC busbars of the first to fourth embodiments described above as the AC busbar ACB of the power stack PST described with reference to FIG. 1, the current balance in the AC busbar can be improved and local current concentration can be alleviated.

[0072] Furthermore, it is possible to reduce uneven heat distribution inside the busbar and the amount of heat generated, enabling efficient power conversion.

[0073] Furthermore, in a power stack PST in which three semiconductor modules SM are connected in parallel, the balance of the current flowing through each semiconductor module SM is improved, and the variations in the life span of the power devices can also be leveled out.

[0074] It should be noted that, within the scope of the present disclosure, the embodiments can be freely combined, modified, or omitted as appropriate.

[0075] The present disclosure described above will be summarized as an appendix.

[0076] (Appendix 1) A power conversion device that converts DC power into AC power, a plurality of semiconductor modules; an AC bus bar commonly connected to the output terminals of the plurality of semiconductor modules, The AC bus bar is It has a multi-layer structure divided into multiple sections in the thickness direction, A power conversion device having an insulating layer partially provided between an upper plate serving as an upper side and a lower plate serving as a lower side.

[0077] (Appendix 2) The upper plate and the lower plate are each having an input section connected to a plurality of semiconductor modules and an output section connected to an external device; 2. The power conversion device according to claim 1, wherein the upper plate and the lower plate are electrically connected in the input section and the output section.

[0078] (Appendix 3) The upper plate and the lower plate are each having an input section connected to a plurality of semiconductor modules and an output section connected to an external device; 2. The power conversion device according to claim 1, wherein the input section and the output section are provided on opposite sides to each other in a plan view.

[0079] (Appendix 4) The upper plate is a first conductive plate having a T-shape in plan view, The lower plate is a second conductor plate having a T-shape in plan view, The input unit a plurality of first through holes provided on one long side of a portion corresponding to a head of the T-shape and penetrating the first conductive plate and the second conductive plate in a thickness direction; The output unit 4. The power conversion device according to claim 2 or 3, having a plurality of second through holes provided at the ends of the portions corresponding to the legs of the T and penetrating the first conductor plate and the second conductor plate in the thickness direction.

[0080] (Appendix 5) The insulating layer is an insulator interposed between the first conductive plate and the second conductive plate, The insulator is 5. The power conversion device according to claim 4, having a T-shaped planar shape and a size and shape that does not cover the arrangement of the plurality of first through holes and the arrangement of the plurality of second through holes.

[0081] (Appendix 6) the first conductive plate and the second conductive plate further include first and second spacers made of conductive material, which are inserted in regions of the first conductive plate and the second conductive plate, respectively, where the array of the plurality of first through holes and the array of the plurality of second through holes are provided; The first spacer and the second spacer are 6. The power conversion device according to claim 5, further comprising a plurality of third through holes and a plurality of fourth through holes corresponding to the plurality of first through holes and the plurality of second through holes, respectively.

[0082] (Appendix 7) a first spacer and a second spacer made of a conductor are inserted in regions of the first conductor plate and the second conductor plate, respectively, where the array of the plurality of first through holes and the array of the plurality of second through holes are provided; The first spacer and the second spacer are a plurality of third through holes and a plurality of fourth through holes corresponding to the plurality of first through holes and the plurality of second through holes, respectively; The insulating layer is 5. The power conversion device according to claim 4, wherein the power conversion device is configured with an air layer present in a gap formed in an area where the first spacer and the second spacer are not provided.

[0083] (Appendix 8) At least one of the first conductive plate and the second conductive plate is a recess formed in a region where the insulating layer is to be provided; the recess has a T-shape in a plan view, and has a size and shape that does not reach the array of the plurality of first through holes and the array of the plurality of second through holes; The insulating layer is 5. The power conversion device according to claim 4, wherein the recess is configured to form an air layer in a gap between the first conductive plate and the second conductive plate.

[0084] (Appendix 9) The first conductive plate and the second conductive plate are 9. The power conversion device according to any one of claims 4 to 8, having a notch portion having an elongated shape in a planar view, the notch portion being arranged to penetrate the center of a portion corresponding to the head of the T and being parallel to the arrangement of the plurality of first through holes.

[0085] (Appendix 10) The first conductive plate and the second conductive plate are 9. The power conversion device according to any one of appendices 4 to 8, having a notch portion having an elongated shape in a planar view, the notch portion being arranged to penetrate closer to the plurality of first through holes than the center of the portion corresponding to the head of the T, and being parallel to the arrangement of the plurality of first through holes.

[0086] (Appendix 11) The plurality of second through holes are 5. The power conversion device according to claim 4, wherein the electrodes are arranged in a row at an angle oblique to the short sides of the legs.

[0087] (Appendix 12) 5. The power conversion device according to claim 4, wherein the first conductor plate and the second conductor plate have the same shape.

[0088] (Appendix 13) In a portion where the insulating layer is provided between the upper plate and the lower plate, 13. The power conversion device according to any one of claims 1 to 12, wherein the direction of current flowing through the upper plate and the direction of current flowing through the lower plate are the same. [Explanation of symbols]

[0089] 100, 100A, 100B, 100C, 200, 300, 400 AC busbar, 101 upper plate, 102 lower plate, DP recess, IBH, OBH fastening hole, ITH, OTH through hole, IS insulator, NP notch, SM semiconductor module.

Claims

1. A power conversion device that converts DC power into AC power, a plurality of semiconductor modules; an AC bus bar commonly connected to the output terminals of the plurality of semiconductor modules, The AC bus bar is It has a multi-layer structure divided into multiple sections in the thickness direction, A power conversion device having an insulating layer partially provided between an upper plate serving as an upper side and a lower plate serving as a lower side.

2. The upper plate and the lower plate are each having an input section connected to a plurality of semiconductor modules and an output section connected to an external device; The power conversion device according to claim 1 , wherein the upper plate and the lower plate are electrically connected in the input section and the output section.

3. The upper plate and the lower plate are each having an input section connected to a plurality of semiconductor modules and an output section connected to an external device; The power conversion device according to claim 1 , wherein the input section and the output section are provided on opposite sides to each other in a plan view.

4. The upper plate is a first conductor plate having a T-shape in plan view, The lower plate is a second conductor plate having a T-shape in plan view, The input unit a plurality of first through holes provided on one long side of a portion corresponding to a head of the T-shape and penetrating the first conductive plate and the second conductive plate in a thickness direction; The output unit 4. The power conversion device according to claim 2, further comprising a plurality of second through holes provided at ends of portions corresponding to legs of a T and penetrating the first conductor plate and the second conductor plate in a thickness direction.

5. The insulating layer is an insulator interposed between the first conductive plate and the second conductive plate, The insulator is The power conversion device according to claim 4 , wherein the power conversion device has a T-shape in plan view and has a size and shape such that it does not cover the array of the first through holes and the array of the second through holes.

6. the first conductive plate and the second conductive plate further include first and second spacers made of a conductor, which are inserted in regions of the first conductive plate and the second conductive plate, respectively, where the array of the plurality of first through holes and the array of the plurality of second through holes are provided; The first spacer and the second spacer are The power conversion device according to claim 5 , further comprising a plurality of third through holes and a plurality of fourth through holes corresponding to the plurality of first through holes and the plurality of second through holes, respectively.

7. a first spacer and a second spacer made of a conductor are inserted in regions of the first conductor plate and the second conductor plate, respectively, where the array of the plurality of first through holes and the array of the plurality of second through holes are provided; The first spacer and the second spacer are a plurality of third through holes and a plurality of fourth through holes corresponding to the plurality of first through holes and the plurality of second through holes, respectively; The insulating layer is The power conversion device according to claim 4 , wherein the spacer is formed by an air layer existing in a gap formed in an area where the first spacer and the second spacer are not provided.

8. At least one of the first conductive plate and the second conductive plate is a recess formed in a region where the insulating layer is to be provided; the recess has a T-shape in a plan view, and has a size and shape that does not reach the array of the plurality of first through holes and the array of the plurality of second through holes; The insulating layer is The power converter according to claim 4 , wherein the recess is formed by an air layer existing in a gap between the first conductive plate and the second conductive plate.

9. The first conductive plate and the second conductive plate are The power conversion device according to claim 4 , further comprising a notch having an elongated shape in a plan view, the notch being provided so as to penetrate a central portion of the portion corresponding to the head of the T and being parallel to the arrangement of the plurality of first through holes.

10. The first conductive plate and the second conductive plate are 5. The power conversion device according to claim 4, further comprising a notch portion having an elongated shape in a planar view, the notch portion being arranged to penetrate closer to the plurality of first through holes than the center of the portion corresponding to the head of the T, and being parallel to the arrangement of the plurality of first through holes.

11. The plurality of second through holes include: The power conversion device according to claim 4 , wherein the electrodes are arranged in a row at an angle oblique to the short sides of the legs.

12. The power converter according to claim 4 , wherein the first conductive plate and the second conductive plate have the same shape.

13. In a portion where the insulating layer is provided between the upper plate and the lower plate, The power conversion device according to claim 1 , wherein the direction of the current flowing through said upper plate is the same as the direction of the current flowing through said lower plate.

Images