Power converter

Abstract

This invention provides a power conversion device that achieves both low inductance and improved heat dissipation. [Solution] The power conversion device comprises a circuit body that performs power conversion, a circuit board having a conductive member on which the circuit body is mounted, a smoothing capacitor having a smoothing capacitor terminal portion connected to the conductive member and electrically connected in parallel with the circuit body, a housing that houses the circuit body, the circuit board, and the smoothing capacitor, and a pressing member fixed to the circuit board or the housing, which electrically connects the smoothing capacitor and the circuit board to each other by pressing the smoothing capacitor terminal portion against the conductive member with an insulating member in between.

Description

Technical Field

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

Background Art

[0002] For example, Patent Document 1 below discloses a configuration in which a smoothing capacitor terminal portion 4 connected to a smoothing capacitor 1 is electrically connected by a connecting member such as solder via a main circuit wiring member 3a of a main circuit portion 3.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In view of the structure of Patent Document 1, an object of the present invention is to provide a power conversion device that achieves both low inductance and improved heat dissipation.

Means for Solving the Problems

[0005] The power conversion device includes a circuit body that performs power conversion, a circuit board having a conductive member on which the circuit body is mounted, a smoothing capacitor having a smoothing capacitor terminal portion connected to the conductive member and electrically connected in parallel with the circuit body, a housing that houses the circuit body, the circuit board, and the smoothing capacitor, and a pressing member that is fixed to the circuit board or the housing and presses the smoothing capacitor terminal portion against the conductive member with an insulating member interposed therebetween to electrically connect the smoothing capacitor and the circuit board to each other.

Effects of the Invention

[0006] It is possible to provide a power conversion device that achieves both low inductance and improved heat dissipation. [Brief explanation of the drawing]

[0007] [Figure 1] An exploded perspective view illustrating a power conversion device according to one embodiment of the present invention. [Figure 2] A perspective view illustrating a power conversion device according to one embodiment of the present invention. [Figure 3] A perspective view illustrating the connection between a smoothing capacitor and a circuit board according to one embodiment of the present invention. [Figure 4] A cross-sectional view illustrating the connection between a pressing member having a protrusion and a smoothing capacitor terminal portion according to one embodiment of the present invention. [Figure 5] A perspective view illustrating the configuration of a pressing member according to one embodiment of the present invention. [Figure 6] An exploded perspective view illustrating a stress relaxation structure for a smoothing capacitor terminal according to one embodiment of the present invention. [Figure 7] A perspective view illustrating the connection of a cooler to a circuit board according to one embodiment of the present invention. [Figure 8] Figure 7 shows a cross-sectional view of the power converter as seen from the R direction. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to the drawings. The following description and drawings are illustrative for illustrating the present invention, and have been omitted and simplified as appropriate for clarity of explanation. The present invention can also be carried out in various other forms. Unless otherwise specified, each component may be singular or plural.

[0009] The positions, sizes, shapes, and ranges of the components shown in the drawings may not represent their actual positions, sizes, shapes, and ranges in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and ranges disclosed in the drawings.

[0010] (One embodiment and overall configuration) (Figure 1) The power conversion device 1 comprises a housing 2, a smoothing capacitor 3, a circuit board 4, a pressing member 5, an insulating member 6, a screw 8, and a circuit body (not shown). Each of the smoothing capacitors 3 has a smoothing capacitor terminal portion 9, which is the positive terminal and negative terminal of the smoothing capacitor 3. The smoothing capacitors 3 smooth the current input and output from the smoothing capacitor terminal portion 9. The circuit board 4 mounts a circuit body (not shown), which is a semiconductor device that performs power conversion. The circuit body converts the DC current input from a DC power supply (not shown) into AC current.

[0011] The pressing member 5 presses against the smoothing capacitor terminal portion 9. The insulating member 6 is positioned between the pressing member 5 and the smoothing capacitor terminal portion 9 to insulate them. The screw 8 is a component that fastens and fixes the pressing member 5 to the housing 2 or the circuit board 4. The screw 8 is inserted into the screw fastening portion 5b of the pressing member 5 (described later) and the column portion 2a of the housing 2 and fastened, so that the pressing member 5 can press the smoothing capacitor terminal portion 9 against the circuit board 4.

[0012] (Figure 2) The housing 2 is a component that houses the power conversion device 1, and houses a smoothing capacitor 3, a circuit board 4, a pressing member 5, an insulating member 6, a screw 8, and a circuit body (not shown). The smoothing capacitor terminal portion 9 (Figure 1) is pressed and crimped to the circuit board 4 by the pressing member 5 and fixed in place. As a result, the smoothing capacitor terminal portion 9 comes into contact with the circuit board 4 and is electrically connected to the circuit board 4. (Figure 3) The circuit board 4 comprises a positive electrode conductive member 4a and a negative electrode conductive member 4b. A circuit body (not shown) is mounted on the circuit board 4, but the circuit body is a conductive member to which the positive electrode conductive member 4a and the negative electrode conductive member 4b are mounted and electrically connected. The pressing member 5 is made of a metal such as stainless steel and has a spring-like deflection structure. The pressing member 5 can obtain a pressing and fixing force by applying the repulsive force generated by this deflection structure to the smoothing capacitor terminal portion 9.

[0013] The pressing member 5 is fixed to the circuit board 4 or the housing 2 (the column portion 2a described later), and applies pressure to press the smooth capacitor terminal portion 9 toward the positive electrode conductive member 4a and the negative electrode conductive member 4b through the insulating member 6 interposed therebetween. As a result, the smooth capacitor terminal portion 9 comes into contact with the positive electrode conductive member 4a and the negative electrode conductive member 4b of the circuit board 4 and is electrically connected, so that the smooth capacitor 3 and the circuit body mounted on the circuit board 4 are electrically connected in parallel.

[0014] With the configuration of such an embodiment of the present invention, the following effects are achieved. Conventionally, the circuit board and the smooth capacitor terminals were electrically connected by fixing them by soldering. However, for example, it was necessary to pass through through-holes provided in the circuit board, and it was necessary to perform processing such as bending the smooth capacitor terminal portion and extending it to the circuit board. Due to such processing, the terminal portion of the smooth capacitor becomes long, resulting in a problem that the inductance increases by that length. In addition, in order to solve this problem, when shortening the smooth capacitor terminals, heat easily moves from the substrate to the smooth capacitor, resulting in a problem that the temperature of the smooth capacitor rises.

[0015] However, with the configuration of an embodiment of the present invention, the step of inserting the smooth capacitor terminal portion 9 into the circuit board 4 for electrical connection becomes unnecessary, and electrical connection to the circuit board 4 can be achieved by pressing with the pressing member 5. Therefore, there is no need to insert the terminal portion 9 into the through-hole of the circuit board 4 as described above. Along with this, terminal processing, soldering processes, welding processes, etc. for passing through the through-hole also become unnecessary. Therefore, since the length of the smooth capacitor terminal portion 9 can be formed shorter than before, reduction of inductance can be realized. As a result, when mounting an EMC filter circuit or a smooth capacitor to suppress noise that increases due to high frequency or large current in the power conversion device 1, problems occurring in the soldering process or welding process can be solved.

[0016] Further, the pressing member 5 is made of a metal material and is fixed to the housing 2 with screws 8, so that the heat of the circuit board 4 and the smoothing capacitor terminal portion 9 can be dissipated to the housing 2. Note that the power conversion device 1 is equipped with a plurality of smoothing capacitors 3, but the number of smoothing capacitors 3 may be plural or singular.

[0017] (Figs. 4, Fig. 5) In Fig. 5, the overall structure of the pressing member 5 is shown, and in Fig. 4, a part of the pressing member 5 is shown. The reference numerals in Fig. 5 encode the portions used for each smoothing capacitor 3, and the other configurations are the same. The pressing member 5 includes a convex portion 5a that can press the smoothing capacitor terminal portion 9 against the circuit board 4. Further, the pressing member 5 includes a screw fastening portion 5b for screwing to the housing 2 or the circuit board 4. The pressing member 5 also includes a plate-like portion 5c formed in the horizontal direction. The convex portion 5a is formed to project from the plate-like portion 5c in the direction of pressing the smoothing capacitor terminal portion 9.

[0018] The insulating member 6 is disposed between the pressing member 5 and the smoothing capacitor terminal portion 9 in order to insulate the convex portion 5a of the pressing member 5 and the smoothing capacitor terminal portion 9, thereby preventing the pressing member 5 and the smoothing capacitor terminal portion 9 from being electrically conductive. The convex portion 5a improves the force with which the pressing member 5 presses against each of the smoothing capacitor terminal portions 9. By having the convex portions 5a in this way, even when there are height variations among the smoothing capacitor terminal portions 9, they can be pressed against the circuit board 4 with uniform pressure without being affected by the tolerance, and each of the smoothing capacitor terminal portions 9 can be reliably pressed. Further, this enables batch fixing and electrical connection of the plurality of smoothing capacitors 3 to the circuit board 4.

[0019] (Fig. 6) The smoothing capacitor terminal portion 9 is equipped with a stress-relieving portion 9a that has an arc shape in the direction in which the pressing member 5 presses against the smoothing capacitor terminal portion 9. The stress-relieving portion 9a is not in contact with the circuit board 4. This structure of the stress-relieving portion 9a of the smoothing capacitor terminal portion 9 allows for the relaxation of stress applied to the smoothing capacitor terminal portion 9 and the dispersion of stress concentration when the smoothing capacitor terminal portion 9 is pressed down by the pressing member 5.

[0020] (Figures 7 and 8) The cooler 7 is constructed of a material with excellent thermal conductivity, and cooling water supplied from the outside flows inside it. By being in contact with the circuit board 4, the cooler 7 cools the circuit board 4 with the refrigerant inside, and also cools the circuit components mounted on the circuit board. The cooler 7 may be placed on the top and bottom surfaces of the circuit board 4, or it may be provided on at least one of the top or bottom surfaces of the circuit board 4.

[0021] The cooler 7 is equipped with screw fastening portions 8a provided in the planar direction. The housing 2 is made of metal and is equipped with column portions 2a that act as bosses. The cooler 7 and the pressing member 5 are fastened together with screws 8 to the circuit board 4 or the column portions 2a (housing 2), thereby fixing them together. With this structure, when current flows through the smoothing capacitor terminal portion 9, the heat generated in the circuit board 4 according to the parasitic resistance is dissipated to the cooler 7, which is fastened together with the pressing member 5. Figure 8 illustrates the heat dissipation path, showing the heat paths 7a to 7c in order of heat transfer.

[0022] The heat generated from the circuit board 4 is transferred to the cooler 7 as shown in the heat path 7a. Next, the heat transferred to the cooler 7 is dissipated by moving within the cooler 7 as shown in the heat path 7b. Then, the heat transferred from the cooler 7 to the column 2a via the screws 8 is transferred from the column 2a to the housing 2 as shown in the heat path 7c. In this way, the transfer and inflow of heat generated in the circuit board 4 to the smoothing capacitor 3 is reduced, improving the heat resistance performance of the smoothing capacitor 3 and improving the heat dissipation performance of both the smoothing capacitor 3 and the circuit board 4 compared to conventional designs. Furthermore, by using the same screws to fasten the cooler 7 and the pressing member 5, and combining them into a single screw 8 as shown, the number of parts can be reduced, resulting in cost reduction.

[0023] In the above-described embodiment of the present invention, the cooling structure was explained using a cooler 7. However, even without using a cooler 7, heat transfer to the smoothing capacitor 3 can be suppressed by heat transfer via the screw 8.

[0024] According to the embodiments of the present invention described above, the following effects and advantages are achieved.

[0025] (1) The power conversion device 1 comprises a circuit body that performs power conversion, a circuit board 4 having conductive members 4a and 4b on which the circuit body is mounted, a smoothing capacitor 3 having a smoothing capacitor terminal portion 9 connected to the conductive members 4a and 4b and electrically connected in parallel with the circuit body, a housing 2 that houses the circuit body, the circuit board 4 and the smoothing capacitor 3, and a pressing member 5 fixed to the circuit board 4 or the housing 2, which electrically connects the smoothing capacitor 3 and the circuit board 4 to each other by pressing the smoothing capacitor terminal portion 9 against the conductive members 4a and 4b with an insulating member 6 in between. In this way, a power conversion device 1 with low inductance can be provided.

[0026] (2) The pressing member 5 has a plate-shaped portion 5c formed in the horizontal direction and a protrusion 5a that protrudes from the plate-shaped portion 5c in the direction that presses the smoothing capacitor terminal portion 9 against it. This allows the smoothing capacitor terminal portion 9 to be pressed with uniform pressure.

[0027] (3) The smoothing capacitor terminal portion 9 has a stress-relieving portion 9a which has an arc shape in the direction in which the pressing member 5 presses against the smoothing capacitor terminal portion 9. This makes it possible to alleviate stress concentration in the smoothing capacitor terminal portion 9.

[0028] (4) The device is equipped with a cooler 7 for cooling the circuit body, and the cooler 7 and the pressing member 5 are fastened together to the circuit board 4 or the housing 2. This improves heat resistance and reduces costs.

[0029] It should be noted that the present invention is not limited to the embodiments described above, and various modifications and combinations of other configurations can be made without departing from the spirit of the invention. Furthermore, the present invention is not limited to having all the configurations described in the embodiments described above, and may also include configurations in which some of those configurations are omitted. [Explanation of Symbols]

[0030] 1. Power converter 2 cabinets 2a Pillar 3. Smoothing Capacitor 4 Circuit boards 4a Positive electrode conductive material 4b Negative electrode conductive material 5 Pressing member 5a Convex part 5b Screw fastening section 5c Plate-shaped part 6. Insulating material 7 Cooler 7a~7c Heat path 8 screws 8a Screw tightening section 9. Smoothing Capacitor Terminal Section 9a Stress relaxation section

Claims

1. A circuit that performs power conversion, A circuit board having conductive members on which the aforementioned circuit body is mounted, A smoothing capacitor having a smoothing capacitor terminal portion connected to the conductive member and electrically connected in parallel with the circuit body, A housing that houses the circuit body, the circuit board, and the smoothing capacitor, The circuit board or housing is fixed to the aforementioned circuit board, and a pressing member is provided to electrically connect the smoothing capacitor and the circuit board to each other by pressing the smoothing capacitor terminal portion against the conductive member with an insulating member in between. Power converter.

2. The pressing member has a plate-like portion formed in the horizontal direction and a protrusion that extends from the plate-like portion in a direction that presses against the smoothing capacitor terminal portion. The power conversion device according to claim 1.

3. The smoothing capacitor terminal portion has a stress-relieving portion that has an arc shape in the direction in which the pressing member presses against the smoothing capacitor terminal portion. The power conversion device according to claim 2.

4. The circuit body is equipped with a cooler, The cooler and the pressing member are fastened together to the circuit board or the housing. The power conversion device according to claim 3.

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