Power conversion device

Abstract

A power conversion device comprises: a semiconductor packing containing a semiconductor element; a printed circuit board containing a wiring layer connected to the semiconductor packing and having a pair of surfaces facing each other; a first heat dissipation element which is brought into contact with a heat dissipation surface of the semiconductor packing via a first thermal conductivity element; and a second heat dissipation element which is brought into contact with a surface formed on the same side as the heat dissipation surface of the semiconductor packing beneath the pair of surfaces of the printed circuit board via a second thermal conductivity element, wherein the first heat dissipation element and the second heat dissipation element are mounted in a state in which they are displaceable relative to each other, and the first thermal conductivity element and the second thermal conductivity element are arranged to partially overlap each other.

Description

Technical field

[0001] The present invention relates to a power conversion device. State of the art

[0002] A power conversion device that alternately converts direct current (DC) and alternating current (AC) power through the switching process of a semiconductor element exhibits a high conversion efficiency and is therefore widely used in consumer applications, in-vehicle applications, railway applications, substations, and the like. In this power conversion device, the semiconductor element generates heat during the switching process, and a printed circuit board (PCB) on which the semiconductor element and various components are mounted, and which incorporates a wiring layer, also generates heat when a large current flows through the wiring layer. Therefore, it is necessary to cool both the semiconductor element and the PCB, and a cooling structure capable of achieving this is required.

[0003] For example, a cooling structure described in PTL 1 was proposed as a cooling structure capable of cooling both the semiconductor element and the printed circuit board. PTL 1 describes a cooling structure for a power conversion device comprising a printed circuit board on which a plurality of circuit bodies, each containing a semiconductor element, are mounted. The AC and DC wiring connecting the plurality of circuit bodies on the printed circuit board are in contact with heat dissipation projections formed in a cooling water channel via an insulating film. List of patent literature

[0004] PTL 1: JP 2023-7184 A Summary of the invention: Technical problem

[0005] In the cooling structure described in PTL 1, a section that contacts the circuit body within the cooling water channel and a section of the heat dissipation protrusion that contacts the printed circuit board (PCB) containing the AC and DC wiring are integrally formed as a single cooling water channel. To achieve high heat dissipation performance by bringing the cooling water channel, circuit body, and PCB into close contact, while ensuring the necessary insulation distance between the cooling water channel, circuit body, and PCB, it is necessary to precisely match the shape of the cooling water channel to the distance between the circuit body surface and the PCB surface.

[0006] However, during the manufacturing process, variations occur in the shape of the cooling water channel and the distance between the circuit body surface and the printed circuit board surface, depending on their respective tolerances. Therefore, precise alignment is difficult, and a certain degree of error is introduced. Depending on the magnitude of this error, the cooling water channel may not be able to make close contact with the circuit body and the printed circuit board, and cooling performance can be impaired. Furthermore, attempting to force close contact creates excessive stress in the circuit body, insulating film, or printed circuit board, which can cause fractures or cracks.

[0007] The present invention was made with regard to the above problems and a main objective is to achieve a power conversion device that can improve reliability while efficiently cooling both a semiconductor element and a printed circuit board. Solution to the problem

[0008] A power conversion device according to the present invention comprises: a semiconductor packing containing a semiconductor element; a printed circuit board containing a wiring layer connected to the semiconductor packing and having a pair of surfaces facing each other; a first heat dissipation element which is brought into contact with a heat dissipation surface of the semiconductor packing via a first thermal conductivity element;and a second heat dissipation element, which is brought into contact with the surface via a second thermal conductivity element, which is formed on the same side as the heat dissipation surface of the semiconductor packing under the pair of surfaces of the printed circuit board, wherein the first heat dissipation element and the second heat dissipation element are mounted in a state in which they are displaceable relative to each other, and the first thermal conductivity element and the second thermal conductivity element are arranged such that they partially overlap each other. Advantageous effects of the invention

[0009] According to the present invention, it is possible to achieve a power conversion device that can improve reliability while efficiently cooling both the semiconductor element and the circuit board. Brief description of the drawings [ Fig. 1] Fig. Figure 1 is a diagram showing a cross-sectional structure of a power conversion device according to a first embodiment of the present invention. [ Fig. 2] Fig. Figure 2 is a diagram showing a cross-sectional structure of a power conversion device according to a second embodiment of the present invention. [ Fig. 3] Fig. Figure 3 is a diagram showing a cross-sectional structure of a power conversion device according to a third embodiment of the present invention. [ Fig. 4] Fig. Figure 4 is a diagram showing a cross-sectional structure of a power conversion device according to a fourth embodiment of the present invention. [ Fig. 5] Fig. Figure 5 is a diagram showing a cross-sectional structure of a power conversion device according to a fifth embodiment of the present invention. [ Fig. 6] Fig. Figure 6 is a diagram showing a cross-sectional structure of a power conversion device according to a sixth embodiment of the present invention. [ Fig. 7] Fig. Figure 7 is a cross-sectional view showing a first structural example of a first heat-conducting element. [ Fig. 8] Fig. Figure 8 is a cross-sectional view showing a second structural example of the first heat-conducting element. [ Fig. 9] Fig. Figure 9 is a cross-sectional view showing a third structural example of the first heat-conducting element. Description of embodiments

[0010] Embodiments of the present invention are described below with reference to the drawings. The following description and drawings are examples used to describe the present invention and have been omitted and simplified as appropriate for clarity of description. The present invention can be carried out in various other forms. Unless otherwise stated, each component can be singular or plural.

[0011] The position, size, shape, area, and the like of each component illustrated in the drawings may not represent the actual position, size, shape, area, and the like, for the purpose of facilitating understanding of the invention. Therefore, the present invention is not necessarily limited to the position, size, shape, area, and the like disclosed in the drawings. (First embodiment)

[0012] Fig. Figure 1 is a diagram showing a cross-sectional structure of a power conversion device according to a first embodiment of the present invention. A power conversion device 1, which is in Fig. As illustrated in Figure 1, the assembly comprises a plurality of semiconductor packings 10, a printed circuit board 20 having a plurality of holes on which the plurality of semiconductor packings 10 are mounted by fitting the semiconductor packings 10 into the respective holes, a first heat dissipation element 31 attached to a heat dissipation surface (a bottom surface in the drawing) of each semiconductor packing 10, a second heat dissipation element 32 attached to the printed circuit board 20, and a water channel cover 40 forming a water channel.

[0013] The semiconductor packing 10 is configured by integrally forming a semiconductor element 11, a first conductor section 12, and a second conductor section 13 with resin. The semiconductor element 11 contained in the semiconductor packing 10 is configured, for example, using an insulated-gate bipolar transistor (IGBT) or a metal-oxide-semiconductor field-effect transistor (MOSFET) and converts direct current power to alternating current power by performing a switching operation in response to a gate signal input from a gate driver circuit (not shown). The semiconductor element 11 has electrodes on both surfaces, and the semiconductor element 11 is electrically connected to the first conductor section 12 and the second conductor section 13 by connecting the electrodes to the first conductor section 12 and the second conductor section 13 via connecting elements 14 and 15, such as solder.

[0014] The printed circuit board 20 contains a plurality of wiring layers 21 and is connected to the first conductor section 12 and the second conductor section 13 via a connecting element 22. Accordingly, each wiring layer 21 is electrically connected to either the first conductor section 12 or the second conductor section 13.

[0015] The first heat dissipation element 31 is connected to the heat dissipation surface of the semiconductor packing 10 via a first thermal conductivity element 51. The first heat dissipation element 31 has a heat dissipation fin on a surface opposite the heat dissipation surface of the semiconductor packing 10, and the heat dissipation fin is located in the water channel formed by the water channel cover 40. This allows the first heat dissipation element 31 to be cooled by the cooling water flowing in the water channel. Accordingly, the heat generated by the switching operation of the semiconductor element 11 is dissipated to the cooling water via the first heat dissipation element 31. It should be noted that the first heat dissipation element 31 is preferably made of a material with water resistance and high thermal conductivity, such as aluminum or copper.

[0016] The first thermal interface element 51 is arranged between the semiconductor packing 10 and the first heat dissipation element 31 to improve the insulation properties and heat dissipation performance between the semiconductor packing 10 and the first heat dissipation element 31. The first thermal interface element 51 has a laminated structure comprising multiple layers.

[0017] The second heat dissipation element 32 is connected via a second thermal conductivity element 52 to a surface (a lower surface in the drawing) located on the same side as the heat dissipation surface of the semiconductor packing 10 of a pair of surfaces on the printed circuit board 20. The second heat dissipation element 32, together with the water channel cover 40, forms part of the water channel and is cooled by the cooling water flowing in the water channel, while preventing the cooling water from leaking out. Accordingly, the heat generated by the current flowing through the wiring layer 21 in the printed circuit board 20 is dissipated to the cooling water via the second heat dissipation element 32.

[0018] The second thermal interface element 52 is arranged between the printed circuit board 20 and the second heat dissipation element 32 to improve the heat dissipation performance between the printed circuit board 20 and the second heat dissipation element 32. The second thermal interface element 52 is configured, for example, using a heat dissipation film or the like.

[0019] As in Fig. As shown in Figure 1, the first heat-conducting element 51 and the second heat-conducting element 52 are arranged so that they partially overlap each other. Accordingly, an insulating distance between the circuit board 20 and the first heat-dissipating element 31 can be ensured, and the insulating properties of the circuit board 20 can be improved with respect to the cooling water flowing around the first heat-dissipating element 31.

[0020] Additionally, as in Fig. Figure 1 shows the first heat dissipation element 31 and the second heat dissipation element 32 arranged so that they partially overlap each other, and a sealing element 33 is arranged in these overlapping sections. That is, the overlapping sections of the first heat dissipation element 31 and the second heat dissipation element 32 are in contact with each other, with the sealing element 33 positioned between them. The sealing element 33 is configured using a flexible, deformable element, such as a waterproof adhesive or a resin O-ring.Accordingly, this structure prevents cooling water from leaking between the first heat dissipation element 31 and the second heat dissipation element 32 and allows the first heat dissipation element 31 and the second heat dissipation element 32 to be offset relative to each other, i.e., allows an error in a relative positional relationship to be absorbed by deformation of the sealing element 33.

[0021] It should be noted that the first heat dissipation element 31 and the second heat dissipation element 32 can be arranged side by side in a lateral direction with a gap between them, so that they do not overlap, and the deformable sealing element 33 can be sandwiched within the gap. Even in this case, the sealing element 33 prevents the cooling water from leaking between the first heat dissipation element 31 and the second heat dissipation element 32, and the deformation of the sealing element 33 allows the first heat dissipation element 31 and the second heat dissipation element 32 to be offset relative to each other, thus making it possible to achieve a structure that can absorb errors in the relative positional relationship between them.In addition, as long as the first heat dissipation element 31 and the second heat dissipation element 32 have a structure that can be offset relative to each other, the first heat dissipation element 31 and the second heat dissipation element 32 can be attached to the heat dissipation surface of the semiconductor packing 10 and the surface of the printed circuit board 20 by any method to connect the power conversion device 1 with the structure as shown in . Fig. 1 shown, to form.

[0022] According to the first embodiment of the present invention described above, the power conversion device 1 comprises the semiconductor packing 10, which contains the semiconductor element 11, the printed circuit board 20, which contains the wiring layer 21, which is connected to the semiconductor packing 10 and has a pair of surfaces facing each other, the first heat dissipation element 31, which is brought into contact with the heat dissipation surface of the semiconductor packing 10 via the first thermal conducting element 51, and the second heat dissipation element 32, which is brought into contact with the surface formed on the same side as the heat dissipation surface of the semiconductor packing 10 under the pair of surfaces of the printed circuit board 20 via the second thermal conducting element 52.The first heat dissipation element 31 and the second heat dissipation element 32 are arranged in a position where they are displaceable relative to each other, and the first thermal conductivity element 51 and the second thermal conductivity element 52 are arranged so that they partially overlap. In this way, even if a defect occurs in the distance between the heat dissipation surface of the semiconductor packing 10 and the surface of the printed circuit board 20, the first heat dissipation element 31 and the second heat dissipation element 32 can be cooled by the cooling water, while the insulating properties of the printed circuit board 20 are ensured by the close contact between the first heat dissipation element 31 and the second heat dissipation element 32. Therefore, it is possible to achieve the power conversion device 1, which can efficiently cool both the semiconductor element 11 and the printed circuit board 20.Additionally, the second heat-conducting element 52 can act as a support element for the first heat-conducting element 51 to reduce deformation of the first heat-dissipating element 31 and the first heat-conducting element 51, thereby preventing breakage of the first heat-conducting element 51.

[0023] In addition, according to the first embodiment of the present invention described above, the first heat dissipation element 31 and the second heat dissipation element 32 are arranged such that sections of them overlap, and the sections are in contact with each other via the deformable sealing element 33. In this way, it is easy to achieve a structure in which, when the first heat dissipation element 31 and the second heat dissipation element 32 are displaceable relative to each other, the first heat dissipation element 31 and the second heat dissipation element 32 are in contact with the heat dissipation surface of the semiconductor packing 10 and the printed circuit board 20, respectively. (Second embodiment)

[0024] Fig. Figure 2 is a diagram showing a cross-sectional structure of a power conversion device according to a second embodiment of the present invention. In the present embodiment, an example is described in which the shape of the second heat dissipation element 32 differs from that of the second heat dissipation element 32 in the power conversion device 1. Fig. 1 differs, which is described in the first embodiment.

[0025] In the present embodiment, the second heat dissipation element 32 contains a section (a section defined by a dotted line 32a in Fig. 2 (surrounded), which is in contact with the circuit board 20 via the second thermal conducting element 52, extends more towards the circuit board 20 than the first thermal dissipation element 31. Accordingly, the second thermal dissipation element 32 is arranged closer to the circuit board 20 compared to the first embodiment, so that the heat dissipation performance of the circuit board 20 is further improved by the second thermal dissipation element 32.

[0026] According to the second embodiment of the present invention described above, the section of the second heat dissipation element 32, which is in contact with the printed circuit board 20 via the second thermal conductivity element 52, projects further towards the printed circuit board than the first heat dissipation element 31. In this way, the heat dissipation performance of the printed circuit board 20 can be further improved. (Third embodiment)

[0027] Fig. Figure 3 is a diagram showing a cross-sectional structure of a power conversion device according to a third embodiment of the present invention. In the present embodiment, an example is described in which the structure of the overlapping sections of the first heat dissipation element 31 and the second heat dissipation element 32 differs from that of the power conversion device 1 described in the first embodiment. Fig. 1. It should be noted that in Fig. 3 only shows a cross-sectional structure around a semiconductor packing 10 and the representation of other sections is omitted.

[0028] In the present embodiment, the second heat dissipation element 32 partially overlaps the first heat dissipation element 31 at a position closer to the circuit board 20 than the first heat dissipation element 31. In this overlapping section, the sealing element 33 is arranged between the first heat dissipation element 31 and the second heat dissipation element 32. Accordingly, the second heat dissipation element 32 and the water channel cover 40, which is attached to the second heat dissipation element 32, can be supported by the first heat dissipation element 31.

[0029] In addition, in the present embodiment, a through-hole 23, which penetrates the plurality of wiring layers 21, is provided in a section of the printed circuit board 20, with which the second heat dissipation element 32 is in contact via the second thermal conductivity element 52. A plating film is formed in the through-hole 23 between the wiring layers 21, and the wiring layers 21 are electrically connected to each other by the plating film. Accordingly, the heat from each wiring layer 21 can be dissipated by the through-hole 23, thus further improving the cooling efficiency of the printed circuit board 20. (Fourth embodiment)

[0030] Fig. Figure 4 is a diagram showing a cross-sectional structure of a power conversion device according to a fourth embodiment of the present invention. In the present embodiment, an example is described in which the power conversion device 1 of Fig. 1, as described in the first embodiment, the through-hole 23 in the circuit board 20 is designed similarly to the third embodiment. It should be noted that also in Fig. 4 similar Fig. 3 only shows a cross-sectional structure around a semiconductor packing 10 and the representation of other sections is omitted.

[0031] In the present embodiment, similar to the third embodiment, the through-hole 23, which penetrates the plurality of wiring layers 21, is provided in the section of the printed circuit board 20 with which the second heat dissipation element 32 is in contact via the second thermal conductivity element 52. Accordingly, the heat from each wiring layer 21 can be dissipated by the through-hole 23, thus further improving the cooling efficiency of the printed circuit board 20. (Fifth embodiment)

[0032] Fig. Figure 5 is a diagram showing a cross-sectional structure of a power conversion device according to a fifth embodiment of the present invention. In the present embodiment, an example is described in which the printed circuit board 20 and the second heat dissipation element 32 are fastened in the power conversion device 1, as described in the fourth embodiment, by a fastening element 24. It should be noted that also in Fig. 5 similar Fig. 3 and Fig. 4 only shows a cross-sectional structure around a semiconductor packing 10 and the representation of other sections is omitted.

[0033] In the present embodiment, the printed circuit board 20 is attached to the second heat dissipation element 32 via the second heat-conducting element 52 by means of the fastening element 24, which is arranged adjacent to the through-hole 23. The fastening element 24 is, for example, a screw and is screwed into a screw hole formed in the second heat dissipation element 32 in such a way that the printed circuit board 20 and the second heat-conducting element 52 are sandwiched between its head and the second heat dissipation element 32. Accordingly, the printed circuit board 20 is attached to the second heat dissipation element 32 by means of the second heat-conducting element 52, and the thickness of the second heat-conducting element 52 can be adjusted by the tightening of the fastening element 24.Therefore, the printed circuit board 20 and the second heat dissipation element 32 can be brought into closer contact with each other more reliably, and the heat from the wiring layer 21 near the through-hole 23 can be transferred via the mounting element 24 to the second heat dissipation element 32 and dissipated from it. As a result, the heat dissipation performance of the printed circuit board 20 can be further improved. (Sixth embodiment)

[0034] Fig. Figure 6 is a diagram showing a cross-sectional structure of a power conversion device according to a sixth embodiment of the present invention. In the present embodiment, an example is described in which a capacitor 60 is connected to the circuit board 20 in the power conversion device 1 described in the fifth embodiment. It should be noted that in Fig. Figure 6 shows only a cross-sectional structure around a semiconductor packing 10 and the capacitor 60, and the representation of other sections is omitted.

[0035] In the present embodiment, the circuit board 20 further comprises an additional through-hole 25, in addition to the through-hole 23 described above, which is formed in the section with which the second heat dissipation element 32 is in contact. By inserting a terminal extending from the capacitor 60 into the through-hole 25, the capacitor 60 is electrically connected to the circuit board 20. The capacitor 60 is provided, for example, in the power conversion device 1 to smooth the DC power input to the semiconductor element 11.

[0036] The printed circuit board 20 has the wiring layer 21 located adjacent to the through-hole 25, which is a connection point to the capacitor 60. The wiring layer 21 includes, for example, a positive electrode wiring and a negative electrode wiring, each connected to the positive and negative electrode sides of the capacitor 60, respectively. This improves the heat dissipation performance of the positive and negative electrode wiring while reducing their inductance.

[0037] Next, the following first to third structural examples for the structure of the first heat conducting element 51 in each of the first to sixth embodiments described above are described. (First structural example)

[0038] Fig. Figure 7 is a cross-sectional view showing a first structural example of the first heat-conducting element 51. Fig. Figure 7 shows an example of a cross-sectional structure of the first heat conduction element 51, which is installed between a semiconductor packing 10 and the first heat dissipation element 31 in the power conversion device 1, which is described in each of the first to sixth embodiments.

[0039] In the first structural example, the first thermal interface element 51 has a structure in which a first layer 51a, a second layer 51b, and a third layer 51c are laminated in that order from the side of the semiconductor packing 10 to the side of the first heat dissipation element 31. The first layer 51a is formed, for example, using a thermal interface material (TIM) that exhibits flexibility and insulating properties, such as heat dissipation grease or a gap filler. The second layer 51b is formed, for example, using an insulating ceramic plate or the like to improve the insulating properties between the semiconductor packing 10 and the first heat dissipation element 31. The third layer 51c is formed using a TIM similar to the first layer 51a, but may or may not exhibit insulating properties.For example, solder material, soldering compound, liquid metal, carbon foil or the like can be used for the third layer 51c as a material that does not have insulating properties.

[0040] In each of the first to sixth embodiments, it is possible to improve the heat dissipation performance of the semiconductor element 11 contained in the semiconductor packing 10 by using the first heat conducting element 51 of the first structural example, while ensuring the insulation property between the semiconductor packing 10 and the first heat dissipation element 31. (Second structural example)

[0041] Fig. Figure 8 is a cross-sectional view showing a second structural example of the first heat-conducting element 51. Similar to Fig. 7 represents Fig. Figure 8 also shows an example of a cross-sectional structure of the first heat conducting element 51, which is installed between a semiconductor packing 10 and the first heat dissipation element 31 in the power conversion device 1, which is described in each of the first to sixth embodiments.

[0042] In the second structural example, the first heat-conducting element 51 has a laminated structure similar to that of the first structural example, which is described with reference to Fig. However, as described in Figure 7, it differs in that the area of ​​the first layer 51a is smaller than the area of ​​the third layer 51c.

[0043] In each of the first to sixth embodiments, by using the first thermal interface element 51 of the second structural example, similar to the first structural example, it is possible to improve the heat dissipation performance of the semiconductor element 11 contained in the semiconductor packing 10, while ensuring the insulating properties between the semiconductor packing 10 and the first thermal interface element 31. Since the amount of TIM used for the first layer 51a can be reduced compared to the first structural example, additional cost reductions and improved reliability can be achieved. (Third structural example)

[0044] Fig. Figure 9 is a cross-sectional view showing a third structural example of the first heat-conducting element 51. Similar to Fig. 7 and Fig. 8 represents Fig.Figure 9 also shows an example of a cross-sectional structure of the first heat conducting element 51, which is installed between a semiconductor packing 10 and the first heat dissipation element 31 in the power conversion device 1, which is described in each of the first to sixth embodiments.

[0045] In the third structural example, the first thermal interface 51 comprises only the first layer 51a and the second layer 51b and does not include the third layer 51c. That is, in the third structural example, the first layer 51a is connected to the heat dissipation surface of the semiconductor packing 10 and the second layer 51b is connected to the first thermal interface 31.

[0046] Since the third layer 51c can be reduced compared to the first and second structural examples by using the first thermal conducting element 51 of the third structural example, a reduction in cost and an improvement in heat dissipation performance can be achieved in each of the first to sixth embodiments.

[0047] It should be noted that the present invention is not limited to the embodiments described above and includes various modifications. For example, the embodiments described above have been described in detail for ease of understanding of the present invention and are not necessarily limited to those that have all the described configurations. Additionally, a part of the configuration of a particular embodiment can be replaced by the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of a particular embodiment. Furthermore, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

[0048] It should be noted that the present invention is not limited to the embodiments described above and various modifications can be made without deviating from the core of the present invention. Reference symbol list 1 Power conversion device 10 semiconductor pack 11 Semiconductor element 12 first ladder section 13 second ladder section 20 circuit boards 21 Wiring layer 23 Through hole 24 Fastening element 31 first heat dissipation element 32 second heat dissipation element 33 Sealing element 40 Water channel cover 51 first heat conducting element 52 second heat-conducting element QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2023-7184 A

[0004]

Claims

[1] Power conversion device comprising: a semiconductor packing containing a semiconductor element; a printed circuit board containing a wiring layer connected to the semiconductor packing and having a pair of surfaces facing each other; a first heat dissipation element which is brought into contact with a heat dissipation surface of the semiconductor packing via a first thermal conductivity element; and a second heat dissipation element which is brought into contact with the surface via a second thermal conducting element, which is formed on the same side as the heat dissipation surface of the semiconductor packing under the pair of surfaces of the printed circuit board, wherein the first heat dissipation element and the second heat dissipation element are installed in a state in which they are movable relative to each other, and The first heat-conducting element and the second heat-conducting element are arranged in such a way that they partially overlap each other. [2] Power conversion device according to claim 1, wherein the first heat dissipation element and the second heat dissipation element are arranged such that sections of them overlap and the sections are in contact with each other via a deformable element. [3] Power conversion device according to claim 1, wherein a section of the second heat dissipation element, which is in contact with the circuit board via the second heat conducting element, protrudes more than the first heat dissipation element in the direction of the circuit board. [4] Power conversion device according to claim 2, wherein the second heat dissipation element partially overlaps the first heat dissipation element at a position that is closer to the circuit board than the first heat dissipation element. [5] Power conversion device according to claim 1, wherein the circuit board has a through hole formed at a position which is in contact with the second heat conducting element via the second heat dissipation element. [6] Power conversion device according to claim 5, wherein the circuit board is attached to the second heat dissipation element via the second heat conducting element by means of a fastening element which is arranged adjacent to the through-hole. [7] Power conversion device according to claim 1, comprising: a capacitor connected to the circuit board, wherein The circuit board has the wiring layer at a position adjacent to a connection point with the capacitor. [8] Power conversion device according to claim 1, wherein the first heat dissipation element is formed by laminating a first layer made of a thermal interface material (TIM), a second layer made of an insulator, and a third layer made of a TIM. [9] Power conversion device according to claim 8, wherein the first heat dissipation element is arranged such that the first layer is in contact with the heat dissipation surface of the semiconductor packing and the third layer is in contact with the first heat conducting element, and an area of ​​the first layer is smaller than an area of ​​the third layer. [10] Power conversion device according to claim 1, wherein the first heat dissipation element is formed by laminating a first layer made of a thermal interface material (TIM) and a second layer made of an insulator.

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