Filter unit, power converter

Abstract

The capacitor elements that make up the filter unit are selectively cooled. [Solution] The filter unit 1 is housed in a housing and comprises a molded busbar 20 having a housing portion 23 formed of resin, a first capacitor element 11 mounted on the housing and having a substantially rectangular shape in plan view, a second capacitor element 12 housed in the housing portion and having a substantially rectangular shape in plan view, and a printed circuit board 4 connected to the busbar, the first capacitor element, and the second capacitor element, wherein the long side of the first capacitor element faces the molded busbar and the short side of the second capacitor element faces the molded busbar.

Description

Technical Field

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

Background Art

[0002] Power conversion devices are required not only to be small and highly efficient but also to have good heat dissipation. In Patent Document 1, there is provided a DC power supply terminal to which DC power is supplied, a capacitor circuit unit that smoothes the DC power and supplies the smoothed DC power to a power conversion circuit unit, a power supply-side conductor that connects the DC power supply terminal and the capacitor circuit unit, a core member that surrounds a part of the power supply-side conductor, and a base that houses the power supply-side conductor and the core member. The power supply-side conductor has a positive electrode-side conductor and a negative electrode-side conductor. The positive electrode-side conductor and the negative electrode-side conductor each have a first conductor portion and a second conductor portion formed by a side surface and a main surface having a larger area than the side surface. The first conductor portions of the positive electrode-side conductor and the negative electrode-side conductor are disposed on one surface of the base via an insulating member. The second conductor portions of the positive electrode-side conductor and the negative electrode-side conductor penetrate the core member with their main surfaces facing each other. The width in a direction orthogonal to the direction in which current flows of the portion of the first conductor portion of each of the positive electrode-side conductor and the negative electrode-side conductor that contacts the insulating member is formed larger than the width in a direction orthogonal to the direction in which current flows of the portion disposed in the core member of each of the second conductor portions of the positive electrode-side conductor and the negative electrode-side conductor. A power conversion device is disclosed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the invention described in Patent Document 1, there is room for improvement in the cooling of the capacitor element. [Means for solving the problem]

[0005] A filter unit according to a first aspect of the present invention is a filter unit housed in a housing, comprising: a molded busbar having a housing portion formed of a resin, a first capacitor element mounted on the housing and having a substantially rectangular shape in plan view, a second capacitor element housed in the housing portion and having a substantially rectangular shape in plan view, and a printed circuit board connected to the busbar, the first capacitor element, and the second capacitor element, wherein the long side of the first capacitor element faces the molded busbar, and the short side of the second capacitor element faces the molded busbar. A power conversion device according to a second aspect of the present invention comprises the above-described filter unit, a power conversion circuit electrically connected to the filter unit, a housing housing the filter unit and the power conversion circuit, and a potting resin filling the gap between the filter unit and the housing, wherein the first capacitor element is mounted on the housing via the potting resin, the second capacitor element is fixed to the molded busbar via the potting resin while housed in the housing, and the molded busbar is mounted on the housing. [Effects of the Invention]

[0006] According to the present invention, the capacitor elements constituting the filter unit can be selectively cooled. [Brief explanation of the drawing]

[0007] [Figure 1] Perspective view of a power converter [Figure 2] Exploded perspective view of a power converter. [Figure 3] Perspective view of the filter unit [Figure 4] Deconstructed perspective view of the filter unit [Figure 5] Side view of the filter unit [Figure 6] Figure 5, section VI-VI [Figure 7] Diagram showing the arrangement of the first and second capacitor elements. [Figure 8] Plan view of a power converter [Figure 9] Figure 8: Cross-sectional view of section IX-IX [Modes for carrying out the invention]

[0008] —First Embodiment— The embodiments of the filter unit and power converter will be described below with reference to Figures 1 to 9.

[0009] Figure 1 is a perspective view of the power converter 100, and Figure 2 is an exploded perspective view of the power converter 100. In this embodiment, mutually orthogonal XYZ axes are shown together to clearly show the correlation between the drawings. In the following description, the Z-axis direction may be referred to as "height," but there are no restrictions on the XYZ axes or the direction of gravity, and the power converter 100 may be positioned in any orientation.

[0010] The power converter 100 comprises a filter unit 1, a power conversion circuit 80, and a housing 90. The housing 90 houses the filter unit 1 and the power conversion circuit 80. The main composition of the housing 90 is preferably metal, but it may be made of materials other than metal. The positive and negative electrodes of the filter unit 1 and the power conversion circuit 80 are electrically connected, respectively. The detailed configuration of the filter unit 1 will be described later.

[0011] In Figure 2, the filter unit 1 is shown largely separated in the Z-axis direction. As shown in Figure 2, the bottom surface of the housing 90, that is, the surface parallel to the XY plane on the Z-axis minus side, is a flat surface and has a first receiving portion 91 and a third receiving portion 93. Although only about half of the first receiving portion 91 and a small part of the third receiving portion 93 are shown in Figure 2, the first receiving portion 91 and the third receiving portion 93 have a tray-like shape.

[0012] The power conversion circuit 80 converts between direct current and alternating current. The power conversion circuit 80 may convert direct current to alternating current, or alternating current to direct current. The filter unit 1 is an EMC (Electro Magnetic Compatibility) circuit. The filter unit 1 includes multiple capacitor elements and filter cores, as will be described later.

[0013] Figure 3 is a perspective view of the filter unit 1, Figure 4 is an exploded perspective view of the filter unit 1, Figure 5 is a side view of the filter unit 1, and Figure 6 is a cross-sectional view of the molded busbar 20. The filter unit 1 comprises a first capacitor element 11, a second capacitor element 12, a third capacitor element 13, a molded busbar 20, a filter core 3, and a printed circuit board 4. The first capacitor element 11 is, for example, a Y capacitor, and the second capacitor element 12 is, for example, an X capacitor. Figures 3 to 5 show two first capacitor elements 11, four second capacitor elements 12, and two third capacitor elements 13, but the number of each capacitor is arbitrary. However, the size and arrangement of each capacitor are related as will be described later.

[0014] The molded busbar 20 is a busbar molded from resin. Specifically, the molded busbar 20 comprises a positive electrode busbar 21 and a negative electrode busbar 22, and a housing portion 23 for housing the second capacitor element 12. The positive electrode busbar 21 and the negative electrode busbar 22 are insulated from the aforementioned resin. The housing portion 23 is also formed from the aforementioned resin.

[0015] A circuit is formed on the printed circuit board 4, and the first capacitor element 11, the second capacitor element 12, the third capacitor element 13, the positive busbar 21, and the negative busbar 22 are connected to it. In other words, the molded busbar 20 is connected to each capacitor element via the printed circuit board 4.

[0016] Each of the positive electrode bus bar 21 and the negative electrode bus bar 22 is a substantially flat plate extending in the X-axis direction. As shown in the cross-sectional view of the molded bus bar 20 in FIG. 6, each of the positive electrode bus bar 21 and the negative electrode bus bar 22 has a short side in the Y-axis direction and a long side in the Z-axis direction. However, this cross-sectional view is for convenience, and the positions of the positive electrode bus bar 21 and the negative electrode bus bar 22 may be interchanged. Also, as a whole, the molded bus bar 20 has a longer length in the Z-axis direction than in the Y-axis direction. Hereinafter, the surface of the molded bus bar 20 in the Z direction, precisely the surface parallel to the XZ plane, is referred to as the "main surface" or the molded bus bar main surface 20A. Since the printed circuit board 4 extends in the XY plane, the molded bus bar main surface 20A and the printed circuit board 4 are orthogonal to each other.

[0017] Each of the first capacitor element 11, the second capacitor element 12, and the third capacitor element 13 is a substantially rectangular parallelepiped, and the terminals provided at the ends on the positive Z-axis side are fixed to the printed circuit board 4. In the state where each terminal is fixed to the printed circuit board 4, the dimension of the first capacitor element 11 in the Z-axis direction is larger than the dimension of the second capacitor element 12 in the Z-axis direction. The dimension of the third capacitor element 13 in the Z-axis direction is the same as the dimension of the first capacitor element 11 in the Z-axis direction. The positive Z-axis sides of the first capacitor element 11 and the second capacitor element 12 are fixed to the printed circuit board 4 parallel to the XY plane. Therefore, the difference in the dimension in the Z-axis direction appears as the difference in the positions of the bottom surfaces of each capacitor element. The bottom surface of the first capacitor element 11 is closer to the housing 90 than that of the second capacitor element 12, and the first capacitor element 11 dissipates heat to the housing 90 more easily than the second capacitor element 12.

[0018] FIG. 7 is a view showing the arrangement of the first capacitor element 11 and the second capacitor element 12, looking down on the XY plane from the positive Z-axis side. FIG. 7 can also be called the perspective view of the filter unit 1 in plan view. The molded bus bar 20 shown in the center of FIG. 7 has the molded bus bar main surfaces 20A at the upper and lower parts shown in the figure. The molded bus bar 20 extends in the X-axis direction, and the first capacitor element 11 and the second capacitor element 12 are arranged side by side in the X-axis direction.

[0019] The first capacitor element 11 has a long side parallel to the X-axis and a short side parallel to the Y-axis. The second capacitor element 12 has a long side parallel to the Y-axis and a short side parallel to the X-axis. Hereafter, the length of the long side of the first capacitor element 11 will be referred to as "11L", and the length of the short side of the second capacitor element 12 will be referred to as "12S". The long side of the first capacitor element 11 is longer than the short side of the second capacitor element 12. That is, "11L" is longer than "12S". Furthermore, the dimension of the first capacitor element 11 in the Z-axis direction is longer than the dimension of the second capacitor element 12 in the Z-axis direction. Therefore, the area of ​​the first capacitor element 11 facing the molded busbar main surface 20A is larger than the area of ​​the second capacitor element 12 facing the molded busbar main surface 20A. The larger the surface area between each capacitor and the molded busbar 20, the easier it is for heat to transfer. Therefore, the first capacitor element 11 receives more heat from the molded busbar 20 than the second capacitor element 12.

[0020] Furthermore, the first capacitor element 11 and the second capacitor element 12 are sandwiched between two filter cores 3 at both ends in the X-axis direction. Each filter core 3 is positioned adjacent to either the first capacitor element 11 or the second capacitor element 12. However, the positions of the first capacitor element 11 and the second capacitor element 12 may be swapped, with the first capacitor element 11 positioned on the negative X-axis side and the second capacitor element 12 on the positive X-axis side.

[0021] Figure 8 is a plan view of the power converter 100, and Figure 9 is a cross-sectional view taken along line IX-IX in Figure 8. In the plan view shown in Figure 8, the filter core 3 is visible through a notch formed in the printed circuit board 4, and it can be seen that another filter core 3 is also located at the positive X-axis end of the printed circuit board 4. However, in this plan view, all capacitor elements are hidden behind the printed circuit board 4. In the cross-sectional view shown in Figure 9, the capacitor elements are arranged from left to right, or in other words, from the negative X-axis to the positive X-axis, in the order of third capacitor element 13, second capacitor element 12, and first capacitor element 11.

[0022] The third capacitor element 13 is fixed to the third receiving portion 93 by potting resin. Since the third receiving portion 93 is fixed to the housing 90 in advance, it can be said that the third capacitor element 13 is fixed to the housing 90 via the potting resin and the third receiving portion 93. The second capacitor element 12 is housed in a housing portion 23, which is part of the molded busbar 20, and the second capacitor element 12 is fixed to the housing portion 23 by potting resin. The molded busbar 20 is fixed to the housing 90 in a configuration not shown. That is, the second capacitor element 12 is fixed to the molded busbar 20 by potting resin while housed in the housing portion 23, and the molded busbar 20 is mounted on the housing 90.

[0023] The first capacitor element 11 is fixed to the first receiving portion 91 by potting resin. Since the first receiving portion 91 is fixed to the housing 90 in advance, it can be said that the first capacitor element 11 is fixed to the housing 90 via the potting resin and the first receiving portion 91. The potting resin used to fix each capacitor element is, for example, one of urethane resin, epoxy resin, or silicone resin. The first receiving portion 91 and the third receiving portion 93 can also be described as enclosures that hold the potting resin.

[0024] According to the first embodiment described above, the following effects and advantages can be obtained. (1) The filter unit 1 is housed in a housing 90. The filter unit 1 comprises a molded busbar 20 having a housing portion 23 formed of resin, in which a positive busbar 21 and a negative busbar 22 are molded from resin; a first capacitor element 11 mounted on the housing 90 and having a substantially rectangular shape in plan view; a second capacitor element 12 housed in the housing portion and having a substantially rectangular shape in plan view; and a printed circuit board 4 connected to the positive busbar 21 and the negative busbar 22, the first capacitor element 11, and the second capacitor element 12. The long side of the first capacitor element 11 faces the molded busbar 20, and the short side of the second capacitor element 12 faces the molded busbar 20. Therefore, the capacitor elements constituting the filter unit 1 can be selectively cooled. Specifically, the first capacitor element 11, which receives a relatively large amount of heat from the molded busbar 20, can directly dissipate heat to the housing 90. The second capacitor element 12, which receives relatively little heat from the molded busbar 20, has a relatively low need for heat dissipation, and therefore is not mounted on the housing 90 but is instead held in place by the molded busbar 20.

[0025] (2) As shown in Figure 6, the molded busbar 20 has a roughly rectangular cross-section. The molded busbar 20 has a long side, the main surface 20A, that faces the first capacitor element and the second capacitor element. Therefore, the first capacitor element 11 is more susceptible to heat from the molded busbar 20 and has a high need to actively dissipate heat to the housing 90.

[0026] (3) The bottom surface of the first capacitor element 11 is closer to the housing 90 than that of the second capacitor element 12. The area of ​​the first capacitor element 11 facing the molded busbar 20 is larger than that of the second capacitor element 12.

[0027] (4) The filter unit 1 comprises at least one filter core 3 having a through hole through which the molded busbar 20 is inserted. The first capacitor element 11 or the second capacitor element 12 is positioned adjacent to the filter core 3 in the direction of extension of the molded busbar 20, i.e., in the X-axis direction. Therefore, even when receiving heat from the filter core 3, the first capacitor element 11 can be cooled by dissipating heat to the housing 90.

[0028] (5) The power converter 100 comprises a filter unit 1, a power conversion circuit 80 electrically connected to the filter unit 1, a housing 90 housing the filter unit 1 and the power conversion circuit 80, and a potting resin that fills the gap between the filter unit 1 and the housing 90. The first capacitor element 11 is mounted on the housing via the potting resin. The second capacitor element 12 is housed in the housing section 23 and fixed to the molded busbar 20 via the potting resin, and the molded busbar 20 is mounted on the housing 90. Therefore, the first capacitor element 11, which receives a relatively large amount of heat from the molded busbar 20, can dissipate heat directly to the housing 90. In addition, the shape of the housing 90 can be simplified by having the second capacitor element 12, which has a relatively low need for heat dissipation, held by the molded busbar 20.

[0029] (6) The power converter 100 includes a third capacitor element 13 that does not face the molded busbar 20. The mounting surfaces of the housing 90 on which the first capacitor element 11 and the third capacitor element 13 are mounted are at the same height. Therefore, the shape of the housing 90 can be simplified.

[0030] (Variation 1) In the embodiment described above, the cross-section of the molded busbar 20 was substantially rectangular, but the cross-sectional shape of the molded busbar 20 is not limited to being substantially rectangular. The cross-section of the molded busbar 20 may be a polygon other than a quadrilateral, or it may be a circle. Furthermore, when the cross-section of the molded busbar 20 is substantially rectangular, a surface with a narrow area may be positioned opposite the first capacitor element 11 and the second capacitor element 12, rather than the main surface 20A of the molded busbar which has a large area. In other words, an arrangement in which the cross-sectional shape shown in Figure 6 is rotated by 90 degrees may be adopted.

[0031] (Modification 2) In the embodiment described above, the filter unit 1 includes a first capacitor element 11, a second capacitor element 12, and a third capacitor element 13. However, the filter unit 1 only needs to include at least the first capacitor element 11 and the second capacitor element 12, and does not need to include the third capacitor element 13.

[0032] (Variation 3) In the embodiment described above, the filter unit 1 is equipped with two filter cores 3. However, it may be equipped with only one filter core 3, or it may be equipped with no filter cores 3 at all.

[0033] (Modification 4) In the embodiment described above, both the positive electrode busbar 21 and the negative electrode busbar 22 were covered with resin to form the molded busbar 20. However, the molded busbar 20 may contain only one of the positive electrode busbar 21 or the negative electrode busbar 22.

[0034] The embodiments and modifications described above may be combined in any way. Although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments that can be conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention. [Explanation of Symbols]

[0035] 1: Filter Unit 3: Filter Core 4: Printed circuit board 11: First capacitor respect 12: Second capacitor element 13: Third capacitor element 20: Molded bus bar 20A: Molded busbar main surface 21: Positive busbar 22: Negative electrode busbar 23: Containment Unit 80: Power conversion circuit 90: Cabinet 91: First receiving section 93: Third receiving section 100: Power converter

Claims

1. In a filter unit housed in a casing, A molded busbar having a housing portion formed by a busbar molded from resin, A first capacitor element mounted in the aforementioned housing, having a substantially rectangular shape in plan view, A second capacitor element, housed in the aforementioned housing and having a substantially rectangular shape in plan view, The busbar, the first capacitor element, and the printed circuit board connected to the second capacitor element are provided, The longer side of the first capacitor element faces the molded busbar, The filter unit has the short side of the second capacitor element facing the molded busbar.

2. A filter unit according to claim 1, The molded busbar has a substantially rectangular cross-section, with its longer side facing the first capacitor element and the second capacitor element, forming a filter unit.

3. A filter unit according to claim 1, The first capacitor element has a bottom surface that is closer to the housing than the second capacitor element. The first capacitor element is a filter unit in which the area facing the molded busbar is larger than that of the second capacitor element.

4. The filter unit according to claim 2, The filter further comprises at least one filter core having a through hole through which the molded busbar is inserted, A filter unit in which the first capacitor element or the second capacitor element is arranged adjacent to the filter core in the extending direction of the busbar.

5. A filter unit according to any one of claims 1 to 4, A power conversion circuit electrically connected to the aforementioned filter unit, The housing that houses the filter unit and the power conversion circuit, A power conversion device comprising a potting resin that fills the gap between the filter unit and the housing, The first capacitor element is mounted on the housing via the potting resin, A power conversion device in which the second capacitor element is housed in the housing and fixed to the molded busbar via the potting resin, and the molded busbar is mounted on the housing.

6. A power conversion device according to claim 5, The system further comprises a third capacitor element that does not face the molded busbar, A power converter in which the mounting surfaces of the housing on which the first capacitor element and the third capacitor element are mounted are of the same height.

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