Power conversion device

Abstract

In order to reduce the influence of noise generated from the power conversion module on the control substrate, a shield plate is used, and the shield plate is of a structure which is fastened to a resin member including a bus bar in a threaded manner from above. In the present invention, a DC bus bar positive electrode (6), a DC bus bar negative electrode (7), and a shield plate (9) are stacked by means of non-conductive members, each of which is mounted as a separate member, the number of components is increased, the number of assembly steps is reduced, and the size is reduced. A bus bar assembly (3) integrated with the AC bus bar (8) and the sensor core (10) is formed by resin (13), and the bus bar assembly (3) is disposed between the power conversion module (4) and the control substrate (2).

Description

Technical Field

[0001] The present application relates to a power conversion device. Background Art

[0002] Vehicles such as electric vehicles and hybrid vehicles are equipped with a power conversion device that performs power conversion between DC power and AC power. The power conversion device includes a power conversion module such as an IGBT (insulated gate bipolar transistor) that performs a conversion operation of converting DC power into three-phase AC power for energy regeneration. A structure is known in which a shielding plate is fastened from above to a resin member including a bus bar by screwing, and the shielding plate is used to reduce the influence of noise generated from the above power conversion module on the control substrate (for example, refer to Patent Document 1). Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Publication No. 2014-168360 Summary of the invention Technical problem to be solved by the invention

[0004] The shield plate, the bus bar, and the resin member are installed as separate components, which has problems in terms of an increase in the number of components, a reduction in the number of assembly steps, and miniaturization.

[0005] The present application has been made in view of the above-mentioned problems, and provides a power conversion device that is excellent in assemblability and can be miniaturized by reducing the number of components. Technical solutions adopted to solve technical problems

[0006] The power conversion device disclosed in the present application is characterized by comprising: A power conversion module, wherein the power conversion module has a switching element, and the power conversion between DC and AC is performed by closing and opening the switching element; a DC bus bar, which is connected to the DC terminal of the power conversion module and has a positive electrode and a negative electrode for inputting and outputting DC current; an AC bus bar, which is connected to the AC terminal of the power conversion module and is used for inputting and outputting AC current; a sensor core, which detects AC current; a shielding plate; and a control substrate, wherein the control substrate includes an electronic circuit for controlling the closing and opening of the power conversion module, wherein the DC bus bar is composed of a flat DC bus bar positive electrode and a flat DC bus bar negative electrode, and the DC bus bar positive electrode, the DC bus bar negative electrode and the shielding plate are stacked by non-conductive components, and together with the AC bus bar and the sensor core, constitute a bus bar assembly integrated by resin, and the bus bar assembly is arranged between the power conversion module and the control substrate. Effects of the Invention

[0007] According to the power conversion device disclosed in the present application, the shielding plate is integrally formed with the DC bus bar, the AC bus bar and the sensor core to form a bus bar assembly, so the threaded fastening of the shielding plate can be omitted, and the number of components can be reduced. In addition, by integrally forming with the bus bar, the height is reduced, thereby also achieving miniaturization. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a perspective view of the power conversion device according to the first embodiment. Figure 2 This is an exploded perspective view of the power conversion device according to the first embodiment. Figure 3 This is a perspective view of the bus bar assembly according to the first embodiment. Figure 4 This is a plan view of the bus bar assembly according to the first embodiment. Figure 5 This is an exploded perspective view of the bus bar assembly according to the first embodiment. Figure 6 This is a plan view of the power conversion module according to Embodiment 1. Figure 7 This is a plan view of the power conversion module according to Embodiment 1. Figure 8 This is a perspective view of the shielding plate according to the first embodiment. Fig. 9 This is a perspective view of the DC bus bar positive electrode according to the first embodiment. Fig.10 This is a perspective view of the negative DC bus bar according to the first embodiment. Fig.11 This is a perspective view of the AC bus bar according to the first embodiment. DETAILED DESCRIPTION

[0009] Hereinafter, preferred embodiments of the power conversion device of the present application will be described with reference to the accompanying drawings. The same reference numerals are used for the same contents and corresponding parts, and their detailed description will be omitted.

[0010] Implementation Method 1 Figure 1 is a perspective view of the power conversion device 1 according to the first embodiment. Figure 2 yes Figure 1 An exploded perspective view of the power conversion device 1 is shown. Figure 1 , Figure 2In the figure, the power conversion device 1 includes a power conversion module 4, a control substrate 2 and a bus bar assembly 3, wherein the power conversion module 4 is accommodated in a frame 5 and constitutes a power conversion unit, the control substrate 2 includes electronic circuits such as ICs (omitted in the figure) for controlling the closing and opening of switching elements such as IGBTs possessed by the power conversion module 4, and the bus bar assembly 3 is electrically connected to the power conversion module 4.

[0011] like Figure 2 As shown, the power conversion module 4 is disposed in the frame 5, and the bus bar assembly 3 is disposed on the power conversion module 4 so as to cover the power conversion module 4. The bus bar assembly 3 is fastened to the frame 5 by screws 15. The control board 2 is mounted on the upper part of the bus bar assembly 3.

[0012] Figure 3 is a perspective view of the busbar assembly 3, Figure 4 : is a top view of the busbar assembly 3. The busbar assembly 3 includes: a DC busbar positive electrode 6 and a DC busbar negative electrode 7 for inputting and outputting DC current; an AC busbar 8 connected to a motor (not shown) and for inputting and outputting AC current converted by the power conversion module 4; a shielding plate 9 for shielding noise generated from the power conversion module 4 by switches such as IGBTs during power conversion; and a sensor core 10 for detecting AC current. For example, a capacitor (not shown) is connected to both ends of the DC busbar positive electrode 6 and the DC busbar negative electrode 7.

[0013] Figure 5 is an exploded perspective view of the busbar assembly 3, Figure 6 , Figure 7 is a top view of the power conversion module 4, Figures 8 to 11 : is a three-dimensional diagram of the components constituting the busbar assembly. When the DC busbar positive electrode 6, the DC busbar negative electrode 7, and the AC busbar 8 are arranged in a metal frame 5, if they are directly in contact with each other, they will form electrical connection points and damage will occur. Therefore, a non-conductive resin 13 (hereinafter referred to as "resin 13") with suitable insulation withstand voltage is used to form an integral body with the DC busbar positive electrode 6, the DC busbar negative electrode 7, and the AC busbar 8, so that the insulation between the DC busbar positive electrode 6, the DC busbar negative electrode 7, and the AC busbar 8 and the frame 5 can be maintained.

[0014] The shielding plate 9 is disposed between the DC bus bar positive electrode 6 and the DC bus bar negative electrode 7 and the control substrate 2 (see Figure 5 and Figure 2 ). In addition, it is arranged in an area on a portion extending from a planar portion of the power conversion module 4 facing the switch element 16. That is, Figure 6As shown, the plane portion 9a covering at least the range 17 of the power conversion module 4 where the switch element 16 is projected (the plane portion covering the predetermined range where the switch element 16 on the power conversion module 4 is located) is arranged on the extended portion of the range 17 of the power conversion module 4. Figure 7 As shown, although a portion of the shielding plate may be cut away and may not cover all of the individual switching elements 16 , there is no problem as long as the shielding plate covers a range sufficient to reduce the noise of the power conversion module 4 .

[0015] The shielding plate 9 is formed of aluminum material, such as Figure 8 As shown, the flat surface portion 9a facing the control substrate 2 has a plurality of bent portions 9b, which are covered with the resin 13 to prevent the resin 13 from falling off. A hole 9d for the screw 15 to pass through is formed in a part of the bent portion 9c. A metal ring 11 is overlapped corresponding to the hole 9d for passing through, and is connected to the frame 5 by the screw 15, so that the noise generated from the power conversion module 4 flows to the frame 5 connected to the vehicle body through the shielding plate 9, and the noise is reduced.

[0016] In addition, if Figure 5 As shown, since the DC bus positive pole 6 is arranged on the power conversion module 4, the DC bus negative pole 7 is arranged on the DC bus positive pole 6, and the shielding plate 9 is arranged on the DC bus negative pole 7 in a stacked manner (in the form of parallel plates), the heat from the power conversion module 4, the DC bus positive pole 6, and the DC bus negative pole 7 can be efficiently released to the frame 5.

[0017] In addition, in order to achieve corrosion resistance, a plating treatment may be applied to the surface of the shielding plate 9. When a pre-plated material is used, it is preferable to select a plating that can withstand the molding temperature. In addition, a hole may be provided to improve the molding performance of the plane portion 9a of the shielding plate 9 within a range that does not affect noise.

[0018] Next, the bus bar assembly 3 formed by integral molding using the resin 13 will be described in detail. When the two DC bus bar positive electrodes 6 and the DC bus bar negative electrodes 7 are integrated using the resin 13, Fig. 9 The DC bus positive pole 6 and Fig.10The DC busbar negative electrode 7 shown in the figure is covered with resin 13 over almost the entire four side surfaces of the extended portion 6a and the extended portion 7a, except for the extended portions 6b and 7b. In addition, the four side surfaces of the extended portion 6a and the extended portion 7a refer to two surfaces (planar portions of the extended portion 6a and 7a) that are opposite to each other in the thickness direction of the extended portion 6a and the extended portion 7a, and two surfaces (side surfaces of the extended portion 6a and 7a) that connect the above two surfaces in the thickness direction. Therefore, the extended portion 6a and the extended portion 7a penetrate the resin 13 in the longitudinal direction, and the resin 13 surrounds the four side surfaces of the extended portion 6a and the extended portion 7a.

[0019] Furthermore, the two DC bus positive electrodes 6 and DC bus negative electrodes 7 are kept parallel and separated from each other, with resin 13 interposed therebetween. The shielding plate 9 is also kept parallel and separated from the DC bus positive electrodes 6 and DC bus negative electrodes 7, with resin 13 interposed therebetween.

[0020] In addition, as an alternative to sandwiching the resin 13 between the DC bus positive electrode 6 and the DC bus negative electrode 7, between the shielding plate 9 and the DC bus positive electrode 6, or between the shielding plate 9 and the DC bus negative electrode 7, it is also possible to Figure 5 As shown, the non-conductive molded members 14 a and 14 b are interposed between the DC bus positive electrode 6 and the DC bus negative electrode 7 , between the shielding plate 9 and the DC bus positive electrode 6 , or between the shielding plate 9 and the DC bus negative electrode 7 .

[0021] In this way, the DC bus bar positive electrode 6 and the DC bus bar negative electrode 7 are arranged on the lower side of the shielding plate 9, and are integrally molded together with the AC bus bar 8 and the sensor core 10 by non-conductive resin 13 except for the flat portion 9a of the shielding plate 9 facing the control substrate 2.

[0022] about Fig.11 The three AC busbars 8 for inputting and outputting AC current are covered with resin 13 over almost the entire four sides of the extended portion 8a, similarly to the DC busbar positive electrode 6 and the DC busbar negative electrode 7. An AC connecting portion 8b is provided at one end of the AC busbar 8. In addition, in the present embodiment, there are three AC busbars 8, but the number is not particularly limited.

[0023] From the viewpoint of power efficiency, copper is preferably used as the material of the DC bus bar positive electrode 6, the DC bus bar negative electrode 7, and the AC bus bar 8. In addition, by making the linear expansion coefficient of the resin 13 close to the thermal expansion coefficient of the DC bus bar positive electrode 6, the DC bus bar negative electrode 7, and the AC bus bar 8, it is possible to eliminate resin peeling or cracking caused by temperature increase in at least one of the DC bus bar positive electrode 6, the DC bus bar negative electrode 7, and the AC bus bar 8.

[0024] According to the above-mentioned structure, since the shielding plate 9 is formed into an integrally molded busbar assembly 3 together with the DC busbar positive electrode 6, the DC busbar negative electrode 7, the AC busbar 8 and the sensor core 10, the threaded fastening of the shielding plate 9 can be omitted, and the number of components can be reduced. Therefore, since the installation process can be simplified, the working efficiency can be improved and the yield rate can be increased. In addition, by integrally molding with the busbar, the height is reduced, thereby miniaturization can also be achieved. In addition, the resin 13 can also cover the shielding plate 9 within a range that does not affect the components installed on the control substrate 2.

[0025] As described above, the screw 15 is used as a fixing method for the control substrate 2, so the nut 12 can be used as a terminal block by integrally molding with the resin 13. In addition, the metal ring 11 can also be integrally molded with the DC bus positive electrode 6, the DC bus negative electrode 7, the AC bus 8, the shielding plate 9, and the sensor core 10. The resin 13 is fastened and fixed to the frame 5 by the screw 15 in a state of facing or contacting with the frame 5. With the above structure, it is possible to withstand vehicle vibration.

[0026] Although the present application describes exemplary embodiments, various features, modes, and functions described in the embodiments are not limited to application to specific embodiments but may be applied to the embodiments alone or in various combinations. Therefore, it is considered that numerous modifications not shown in the examples are also included in the technical scope disclosed in the specification of the present application. Explanation of symbols

[0027] 1: power conversion device, 2: control substrate, 3: busbar assembly, 4: power conversion module, 5: frame, 6: DC busbar positive pole, 7: DC busbar negative pole, 8: AC busbar, 9: shielding plate, 10: sensor core, 11: metal ring, 12: nut, 13: resin, 14a, 14b: non-conductive molded components, 15: screw, 16: switch element.

Claims

1. A power conversion device, It is characterized in that include: A power conversion module, wherein the power conversion module has a switch element, and performs direct current and alternating current power conversion by closing and opening the switch element; A DC bus bar, the DC bus bar is connected to the DC terminal of the power conversion module and has a positive pole and a negative pole for inputting and outputting DC current; an AC bus bar, the AC bus bar being connected to the AC terminal of the power conversion module and being used for inputting and outputting AC current; A sensor core, wherein the sensor core detects the alternating current; Shielding plate; as well as a control substrate, the control substrate comprising an electronic circuit for controlling the closing and opening of the power conversion module, The DC busbar is composed of a flat DC busbar positive electrode and a flat DC busbar negative electrode. The DC busbar positive electrode, the DC busbar negative electrode and the shielding plate are stacked by non-conductive components, and together with the AC busbar and the sensor core, they constitute a busbar assembly integrated by non-conductive resin. The busbar assembly is arranged between the power conversion module and the control substrate.

2. The power conversion device according to claim 1, It is characterized in that The shield plate has a planar portion that covers a predetermined range on the power conversion module where the switch element is located, so that noise generated by the power conversion module flows to the frame.

3. The power conversion device according to claim 2, It is characterized in that The shield plate has a bent portion at an end portion, the bent portion is covered with the non-conductive resin, and a surface of the shield plate facing the control board is exposed from the non-conductive resin.

4. The power conversion device according to any one of claims 1 to 3, It is characterized in that The shielding plate is connected to the frame through a metal ring.

5. The power conversion device according to claim 4, It is characterized in that The metal ring is integrated with the bus bar assembly through the non-conductive resin.

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