Power Conversion Device

Abstract

To provide a power conversion device which is compact and inexpensive while securing vibration resistance of a capacitor for noise countermeasures.SOLUTION: A power conversion device comprises: a capacitor 11 for noise countermeasures which is mounted on a printed circuit board 50 in such a manner that a main body portion rises; a capacitor case 60 which encloses the main body portion of the capacitor for noise countermeasures and of which the side separated from the printed circuit board 50 is opened; a fixing member 72 of which both the ends are fixed with two locations of an upper end face 61fu of a frame part 61 opposed to each other with the capacitor 11 for noise countermeasures interposed therebetween and which is fixed with the main body portion and fixes the capacitor 11 for noise countermeasures to the capacitor case 60; and fastening members 8a and 8b which fix the printed circuit board 50 and the frame body 60 together with a housing 40.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Electric vehicles, such as electric vehicles and hybrid vehicles, that use a motor as a drive source are equipped with multiple power conversion devices. Examples of power conversion devices include a charger that converts commercial AC power into DC and charges the high-voltage battery, a DC / DC converter that converts the DC power of the high-voltage battery into the voltage (e.g., 12 V) of a battery for auxiliary equipment, and an inverter that converts DC power from the battery into AC power for the motor.

[0003] In recent years, in order to improve fuel efficiency and expand the interior space of electric vehicles, there has been a demand for reducing the mounting space required for onboard equipment, which has led to demands for smaller and less costly power conversion devices. However, miniaturizing power conversion devices can increase noise due to electromagnetic coupling between components, necessitating the use of noise suppression capacitors, also known as line bypass capacitors. In such cases, noise suppression capacitors are mounted on printed circuit boards, but when installed in the engine compartment of an electric vehicle, particularly high vibration resistance is required, so noise suppression capacitors with large volumes and long terminals require vibration suppression.

[0004] Therefore, a power conversion device has been proposed in which the noise suppression capacitor is removed from the printed circuit board, and the noise suppression capacitor is housed in a case separate from the printed circuit board and fixed with a fixing member (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2014-39384 A (paragraphs 0045 to 0051, Figure 6) Summary of the Invention [Problem to be solved by the invention]

[0006] However, when the noise suppression capacitor is housed in a separate case, additional components such as fastening parts and fastening members are required to secure the case to the housing, which poses the problem of increasing the size and cost of the power conversion device.

[0007] The present application discloses a technique for solving the above-mentioned problems, and aims to obtain a power conversion device that ensures the vibration resistance of a noise suppression capacitor and can be made smaller and less expensive. [Means for solving the problem]

[0008] The power conversion device disclosed in the present application is characterized by comprising: a power conversion circuit formed using a plurality of semiconductor elements; a housing for accommodating the power conversion circuit; a printed circuit board on which an electrode pattern is formed; terminals protruding from a main body portion, one of which is electrically connected to the power conversion circuit via the electrode pattern and the other terminal is electrically connected to the housing via the electrode pattern; a noise reduction capacitor mounted on the printed circuit board so that the main body portion rises from the printed circuit board; a case surrounding the main body portion and having an opening on the side away from the printed circuit board; a fixing member fixed to the main body portion and fixing the noise reduction capacitor to the case; and a fastening member for fixing the printed circuit board and the case together with the housing. [Effects of the Invention]

[0009] According to the power conversion device disclosed in the present application, vibration countermeasures for noise suppression capacitors can be realized on a printed circuit board, thereby ensuring the vibration resistance of the noise suppression capacitors and providing a small, inexpensive power conversion device. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a circuit diagram for explaining a configuration of a power conversion device according to a first embodiment. [Figure 2] FIG. 2 is a plan view for explaining the configuration of a printed circuit board that forms the power conversion device according to the first embodiment. [Figure 3] 1 is a plan view of a printed circuit board forming a power converter according to a first embodiment, from which a capacitor case, a fixing member, and a fastening member have been removed. [Figure 4] 3 is a cross-sectional view seen from the front side for explaining the configuration of a printed circuit board that forms the power conversion device according to the first embodiment. FIG. [Figure 5] 3 is a cross-sectional view seen from the side for explaining the configuration of a printed circuit board that forms the power conversion device according to the first embodiment. FIG. [Figure 6] FIG. 10 is a plan view for explaining the configuration of a printed circuit board that forms a power conversion device according to a first modified example of the first embodiment. [Figure 7] FIG. 10 is a plan view for explaining the configuration of a printed circuit board that forms a power conversion device according to a second modification of the first embodiment. [Figure 8] FIG. 10 is a cross-sectional view of the front side for illustrating the configuration of a printed circuit board that forms a power converter according to a third modification of the first embodiment. [Figure 9] FIG. 10 is a plan view for explaining the configuration of a printed circuit board that forms a power conversion device according to a fourth modification of the first embodiment. [Figure 10] FIG. 10 is a plan view for illustrating the configuration of a printed circuit board that forms a power conversion device according to a fifth modification of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Embodiment 1 Fig. 1 to Fig. 5 are diagrams for explaining the configuration of the power conversion device according to the first embodiment, in which Fig. 1 is a circuit diagram including input and output devices for explaining the configuration of the power conversion device, Fig. 2 is a plan view for explaining the configuration of a printed circuit board that forms the power conversion device, and Fig. 3 is a plan view in which the capacitor case, fixing members, and fastening members are removed from Fig. 2 and the terminal positions of the noise suppression capacitor are depicted. Also, Fig. 4 is a cross-sectional view taken along line AA in Fig. 2 to show the cross-sectional shape as seen from the front side of the printed circuit board, and Fig. 5 is a cross-sectional view taken along line BB in Fig. 2 to show the cross-sectional shape as seen from the side of the printed circuit board.

[0012] In order to clarify the characteristics of the present application, Figs. 2 to 5 focus on the noise suppression capacitor of the power converter and omit other components. Furthermore, actual power converters, including the DC / DC converter exemplified in the present application, are surrounded by a housing. Furthermore, as a means of reducing the projected area of ​​the power converter and making it smaller, the configuration is based on the assumption that multiple semiconductor elements, such as switching elements, arranged in the housing, the components of the power conversion circuit other than the multiple semiconductor elements, and the printed circuit board on which the noise suppression capacitor are arranged are arranged so as to overlap in a top view of the printed circuit board. Furthermore, in plan views other than Fig. 3, including the following modified examples, the outline of the electrode pattern hidden by components is indicated by dashed lines. Furthermore, in Fig. 2, the shape of the frame of the capacitor case is also indicated by dashed lines.

[0013] The power conversion device according to the first embodiment will be described in detail below with reference to the drawings. Note that, in the present application, a DC / DC converter that steps down the voltage of DC power to a desired voltage will be described as an example, but the present invention is not limited to this. It goes without saying that any power conversion device equipped with a noise suppression capacitor may be a boost converter, an AC / DC inverter, a DC / AC inverter, or a combination thereof.

[0014] [DC / DC converter circuit configuration] 1, a DC / DC converter 1, which is a power supply device of the present invention, steps down DC power supplied from an input power source 91 (high-voltage battery) to a desired voltage and supplies it to an external load 92 or an output power source 93 (low-voltage battery). A noise suppression capacitor circuit 10, a smoothing capacitor 20, and a power conversion circuit 30 are connected to the DC / DC converter 1.

[0015] The noise suppression capacitor circuit 10 is made up of four capacitors 11a, 11b, 11c, and 11d (when not distinguishing between them, they will be referred to as noise suppression capacitors 11). Capacitors 11a and 11b have one terminal connected to the input power supply 91 and the positive side of the power conversion circuit 30, and the other terminal connected to the housing 40, thereby being grounded. Capacitors 11c and 11d have one terminal connected to the input power supply 91 and the negative side of the power conversion circuit 30, and the other terminal connected to the housing 40, thereby being grounded.

[0016] The power conversion circuit 30 is arranged in the following order from the input side to the output side: inverter circuit 31, transformer 32, rectifier circuit 33, smoothing reactor 34, and smoothing capacitor 35. The inverter circuit 31 is made up of four semiconductor switching elements 31a to 31d, and the rectifier circuit 33 is made up of two rectifier elements 33a and 33b. The power conversion circuit 30 further includes a control circuit 36 ​​that includes a voltage detection circuit, a current detection circuit, etc., and controls the operation of the semiconductor switching elements 31a to 31d of the inverter circuit 31.

[0017] Here, all four noise suppression capacitors 11 have the same capacitance. Since the smaller the capacitance of a noise suppression capacitor, the better the impedance characteristics in the high frequency band, by dividing the capacitance among multiple capacitors, it is possible to obtain filter performance with a high attenuation effect in the high frequency band.

[0018] The four semiconductor switching elements 31a to 31d that make up the inverter circuit 31 are, for example, MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). A control circuit 36 ​​drives the semiconductor switching elements 31a to 31d by turning them on and off via control lines using PWM (Pulse Width Modulation). A connection point between the source of semiconductor switching element 31a and the drain of semiconductor switching element 31b is connected to one end of a primary winding of a transformer 32, and a connection point between the source of semiconductor switching element 31c and the drain of semiconductor switching element 31d is connected to the other end of the primary winding of the transformer 32.

[0019] Semiconductor rectifying elements 33e and 33f that form a rectifying circuit are connected to the secondary winding of the transformer 32. Rectifying diodes, for example, are used for the semiconductor rectifying elements 33e and 33f. For secondary-side rectification, a smoothing reactor 34 and a smoothing capacitor 35 are connected downstream of the semiconductor rectifying elements 33e and 33f. The terminal of the smoothing capacitor 35, which is connected to the negative side of the output power supply 93, is connected to the housing 40 and is thereby grounded.

[0020] [Mechanical structure of DC / DC converter] 4, printed circuit board 50 is a two-layer board in which electrode patterns 55a to 55d are formed on one surface (the upper surface in the figure) of substrate 51, and electrode patterns 55e and 55f (referred to as electrode pattern 55 when not distinguished from one another) are formed on the other surface (the lower surface in the figure). Electrode pattern 55c on one surface is electrically connected to electrode pattern 55e on the other surface via through-hole 56a, and electrode pattern 55d on one surface is electrically connected to electrode pattern 55f on the other surface via through-hole 56b.

[0021] Furthermore, a plurality of through holes 56a and 56b are arranged in a circular ring shape (FIG. 3), and through holes 58a and 58b are provided in the center thereof for passing fastening members 8a and 8b, which will be described later.

[0022] Capacitor 11b has terminals 12c and 12d spaced apart from each other on the bottom surface (the lower surface in the figure) of the main body, which protrude downward. Capacitor 11d also has terminals 12g and 12h spaced apart from each other on the bottom surface, which protrude downward. Similarly, capacitor 11a also has terminals 12a and 12b spaced apart from each other on the bottom surface, which protrude downward. Capacitor 11c also has terminals 12e and 12f spaced apart from each other on the bottom surface, which protrude downward. When there is no need to distinguish between the individual terminals, they will be referred to as terminals 12.

[0023] Each of the four noise suppression capacitors 11 is mounted on the mounting surface 50fm of the printed circuit board 50 with the terminal 12 facing the printed circuit board 50, and the main body rises to a predetermined height from the mounting surface 50fm. At this time, one terminal 12a, 12c of each of the capacitors 11a, 11b is connected to the positive side of the power conversion circuit 30 via the electrode pattern 55a, as shown in Fig. 3. Similarly, one terminal 12e, 12g of each of the capacitors 11c, 11d is connected to the negative side of the power conversion circuit 30 via the electrode pattern 55b.

[0024] 5, the other terminals 12f and 12h of capacitors 11c and 11d are connected to housing 40 via electrode pattern 55d, through-hole 56b, and electrode pattern 55f. Similarly, the other terminals 12b and 12d of capacitors 11a and 11b are connected to housing 40 via electrode pattern 55c, through-hole 56a, and electrode pattern 55e.

[0025] Furthermore, electrode pattern 55c, to which terminals 12b and 12d are connected, is also connected to housing 40 via a conductive member 63a, such as iron, embedded in flange 62a of capacitor case 60 by insert molding, and via fastening members 8a, such as screws. Similarly, electrode pattern 55d, to which terminals 12f and 12h are connected, is also connected to housing 40 via a conductive member 63b, such as iron, embedded in flange 62b of capacitor case 60 by insert molding, and via fastening members 8b, such as screws. When flanges 62a and 62b are not to be distinguished, they will be referred to as flange 62.

[0026] Although the printed circuit board 50 is shown as a two-layer board in FIGS. 4 and 5, it may be a multi-layer board having two or more layers.

[0027] 2, capacitor case 60 is formed with an annular frame 61, and flanges 62a and 62b are formed to protrude from frame 61. When fastening members 8a and 8b are used to bring flanges 62a and 62b into close contact with printed circuit board 50, capacitor case 60 is fixed to printed circuit board 50 so that frame 61 surrounds the side surfaces (top, bottom, left, and right surfaces in the figure) of noise suppression capacitor 11.

[0028] The height of the frame portion 61 when the capacitor case 60 is fixed to the printed circuit board 50 is aligned with the top surface 11fu of the noise countermeasure capacitor 11, i.e., the height of the frame portion 61 rising from the printed circuit board 50 (mounting surface 50fm). Therefore, the top surface 11fu of the noise countermeasure capacitor 11 and the top end surface 61fu of the frame portion 61 are flush with each other. Meanwhile, fixing members 72a and 72b (referred to as fixing members 72 when not distinguished from each other) made of silicon or the like and having a vibration damping function are arranged to bridge the opposing sides of the frame portion 61 with the noise countermeasure capacitor 11 in between. This mechanically fixes the main body portion of the noise countermeasure capacitor 11 (the portion rising from the printed circuit board 50).

[0029] This eliminates the need for bus bars to connect the terminals of the noise suppression capacitor to the power conversion circuit and the housing, which were previously required to provide a separate component for improving the vibration resistance of the noise suppression capacitor as described in the background art.Furthermore, this eliminates the need for additional components such as fastening members for fixing the capacitor case to the housing, making it possible to realize a small, inexpensive power conversion device while suppressing increases in costs.

[0030] 4 and 5, the connection points between electrode patterns 55c and 55d and housing 40 are the same as the points where printed circuit board 50 and capacitor case 60 are fixed. This eliminates the need to provide separate connection points on printed circuit board 50 between terminals 12 of noise suppression capacitors 11 and housing 40, making it possible to reduce the projected area of ​​printed circuit board 50 and the need for additional fastening members. This makes it possible to reduce the size and cost of power conversion devices such as DC / DC converter 1.

[0031] Furthermore, if the capacitor case is provided separately from the printed circuit board, a bus bar is required to electrically connect the noise suppression capacitor to the power conversion circuit and the housing. However, in the present application, conductive members 63a and 63b are embedded in the flange portion 62a of the capacitor case 60 by insert molding or the like. This strengthens the fixation of the capacitor case 60 to the housing 40 and facilitates the formation of a current path to the housing 40, eliminating the need for additional members such as the bus bar. Furthermore, a path is added via the conductive members 63a and 63b and fastening members 8a and 8b, such as screws, as a connection path from the other terminals 12b, 12d, 12f, and 12h of the noise suppression capacitor 11 to the housing 40.

[0032] This makes it possible to reduce the impedance from the other terminals 12b, 12d, 12f, and 12h of noise suppression capacitor 11 to housing 40, improving filter performance in high frequency bands. This makes it possible to reduce the overall capacitance and number of noise suppression capacitors 11, thereby enabling the power conversion device to be made smaller and less expensive.

[0033] 2, the fixing members 72 are arranged and fixed perpendicular to two opposing sides of the frame portion 61 of the capacitor case 60. The fixing members 72 are arranged with their longitudinal directions aligned with the direction in which the vibration of each of the noise suppression capacitors 11 is greatest. This ensures vibration resistance while reducing the amount of fixing members 72 used compared to when fixing the noise suppression capacitors by filling the capacitor case with fixing members, thereby reducing the cost of the power conversion device.

[0034] 2, 4, and 5, the capacitor case 60 is made up of an annular frame 61 and a flange 62 extending from the outer peripheral surface of the frame 61, so that it surrounds only the side surfaces of the noise suppression capacitor 11 and is open at the top. In this way, the noise suppression capacitor 11 can be mounted on the printed circuit board 50, and then the capacitor case 60 can be attached to the printed circuit board 50. This makes it possible to separate the process of mounting components onto the printed circuit board 50, including the noise suppression capacitor 11, from the process of assembling the capacitor case 60, eliminating the need for complex assembly processes and reducing manufacturing costs, thereby enabling a lower cost power conversion device.

[0035] 3, the press-fit structure is formed by press-fit holes 57a, 57b provided in printed circuit board 50, which also serve to position capacitor case 60, and press-fit pins 68a, 68b provided on capacitor case 60 shown in Fig. 5. This eliminates the need for a dedicated jig for determining the position of capacitor case 60 during assembly or a fixing member for temporarily fixing printed circuit board 50 and capacitor case 60, and reduces the number of steps.

[0036] In addition, since the printed circuit board 50 and the capacitor case 60 can be fixed (temporarily fixed) without being assembled to the housing 40, it is possible to apply a fastening material before assembling the printed circuit board 50 to the housing 40, thereby improving workability. As a result, it is possible to reduce manufacturing costs, and the cost of the power conversion device can be reduced.

[0037] 3 and 5, the case where a press-fit structure is provided is described, but the present invention is not limited to this. Even if only a positioning structure for the printed circuit board 50 and the capacitor case 60 is provided, or even if a fitting structure such as a snap fit is provided between the printed circuit board 50 and the capacitor case 60, the number of steps can be reduced, and the cost of the power conversion device can be reduced.

[0038] 2 and 5, the frame 61 of the capacitor case 60 has a thick portion 61k where the fixing member 72 is fixed and is thicker than other portions. This improves the adhesion between each of the noise suppression capacitors 11 and the fixing member 72 on the capacitor case 60, thereby improving vibration resistance.

[0039] 5, the thick-walled portion 61k of the capacitor case 60 has a shape that is inclined so that the thickness becomes thinner in the direction in which the terminals 12 protrude from the element body portion of the noise suppression capacitor 11 at a height from the printed circuit board 50. This makes it possible to avoid interference between the capacitor case 60 (frame portion 61) and the solder that connects the noise suppression capacitor 11 to the electrode pattern 55. As a result, the assembly of the capacitor case 60 is improved, and manufacturing costs can be reduced, resulting in a lower cost power conversion device.

[0040] 3, the arrangement and connection relationship of noise suppression capacitor 11 and electrode patterns 55a-55d will now be described. Capacitors 11a and 11c are arranged so that line segment Lab connecting terminals 12a and 12b and line segment Lef connecting terminals 12e and 12f form a single straight line, and terminals 12a and 12e face each other. Capacitors 11b and 11d are arranged so that line segment Lcd connecting terminals 12c and 12d and line segment Lgh connecting terminals 12g and 12h form a single straight line, and terminals 12c and 12g face each other.

[0041] Furthermore, terminals 12a and 12c are connected to electrode pattern 55a, terminals 12e and 12g are connected to electrode pattern 55b, terminals 12b and 12d are connected to electrode pattern 55c, and terminals 12f and 12h are connected to electrode pattern 55d. In this manner, it is possible to increase the area of ​​electrode patterns 55c and 55d connected to housing 40 without reducing the electrode patterns in order to ensure an insulating distance between components, and the pattern width of electrode pattern 55 can be increased.

[0042] This makes it possible to reduce the impedance from the other terminal 12 of the noise suppression capacitor 11 to the housing 40, improving the filter performance in the high frequency band. This also makes it possible to reduce the capacitance and number of the noise suppression capacitors 11, thereby enabling the power conversion device to be made smaller and less expensive.

[0043] Variant. In the above example, the capacitor case is described as being configured to surround only the side surfaces of the noise suppression capacitors, but this is not limiting. In the first modified example, an example is described in which walls are provided to separate the capacitors, and in the second modified example, an example is described in which the capacitor case is configured to also cover the bottom surfaces of the noise suppression capacitors.

[0044] First variant. Fig. 6 is a plan view illustrating the configuration of a printed circuit board forming a power converter according to a first modified example, with fixing members removed. As shown in Fig. 6, in the power converter (DC / DC converter 1) according to the first modified example, walls 61s are provided inside frame 61 of capacitor case 60 to separate each of noise suppression capacitors 11.

[0045] By doing this, the accuracy of placement of each noise countermeasure capacitor 11 can be improved while also improving the adhesion of the fixing members 72a, 72b to the noise countermeasure capacitor 11 and the capacitor case 60, thereby further improving vibration resistance.

[0046] Second variant. Fig. 7 is a plan view illustrating the configuration of the printed circuit board that forms the power conversion device according to the second modified example, with the fastening members removed, similar to Fig. 6. As shown in Fig. 7, in the power conversion device (DC / DC converter 1) according to the second modified example, a bottom plate portion 61b that separates the printed circuit board 50 and the noise suppression capacitor 11 is provided at the bottom of the frame portion 61 of the capacitor case 60.

[0047] Furthermore, walls 61s that separate the noise countermeasure capacitors 11 are provided inside the frame 61. This improves the accuracy of arranging each of the noise countermeasure capacitors 11 while also improving the adhesion of the fixing members 72a, 72b to the noise countermeasure capacitors 11 and the capacitor case 60, thereby further improving vibration resistance.

[0048] Here, the bottom plate portion 61b may be configured to have a guide shape such as a cylindrical shape or a conical shape in order to guide each terminal 12 of the noise countermeasure capacitor 11 into a through-hole (not shown) of the printed circuit board 50. When the bottom plate portion 61b has a guide shape, first, each noise countermeasure capacitor 11 is incorporated into the capacitor case 60 and fixed with the fixing members 72a, 72b, and then they are mounted on the printed circuit board 50.

[0049] This improves the ease of inserting each terminal 12 of the noise suppression capacitor 11 into the through-holes of the printed circuit board 50, improving the yield during assembly and reducing manufacturing costs, thereby further reducing the cost of the power conversion device.

[0050] Third variant. In the above example, the case where the noise suppression capacitor, capacitor case, and fastening member are arranged on the upper surface side of the printed circuit board (opposite the housing) has been described, but the present invention is not limited to this. In the third modified example, an example where the noise suppression capacitor, capacitor case, and fastening member are arranged between the printed circuit board and the housing will be described. Fig. 8 is a cross-sectional view corresponding to Fig. 4, which is used to explain the configuration of a power conversion device according to the third modified example.

[0051] As shown in Fig. 8, a power conversion device (DC / DC converter 1) according to a third modified example may be configured such that noise suppression capacitor 11, electrode patterns 55a to 55d, capacitor case 60, and fixing member 72 are arranged on the surface of printed circuit board 50 facing housing 40. Normally, dead space is generated when multiple semiconductor elements arranged on a housing and the printed circuit board are stacked on top of each other when viewed from above. However, in this modified example, by storing noise suppression capacitor 11, capacitor case 60, and fixing member 72 on the surface of printed circuit board 50 facing housing 40, the generated dead space can be effectively utilized, allowing the power conversion device to be made more compact.

[0052] Also in this modification, each of the terminals 12 of the noise suppression capacitor 11 is connected to the housing 40 via the shortest path via the conductive members 63a, 63b of the capacitor case 60. This reduces the impedance of the path and improves the filter performance in the high frequency band. This makes it possible to reduce the overall capacitance and number of noise suppression capacitors 11, thereby enabling the power conversion device to be made smaller and less expensive.

[0053] Fourth Variant. In this fourth modification, an example will be described in which the arrangement and connection relationship between the noise suppression capacitor and the electrode patterns are different from the above examples. Fig. 9 is a plan view corresponding to Fig. 2 of the first embodiment, for explaining the configuration of a printed circuit board that forms a power conversion device according to the fourth modification, and the positions of the terminals are indicated by dashed circles to explain the connection relationship between the terminals and the electrode patterns.

[0054] In the power conversion device (DC / DC converter 1) according to the fourth modification, as shown in Fig. 9, terminals 12b and 12d are connected to electrode pattern 55a, and terminals 12c and 12g are connected to electrode pattern 55b. Terminals 12a and 12e are connected to electrode pattern 55c, and terminals 12f and 12h are connected to electrode pattern 55d. This is a difference from the description of Fig. 3 in the first embodiment.

[0055] This eliminates the need to ensure an insulating distance between terminals 12a and 12e, and between terminals 12c and 12g of noise suppression capacitor 11, allowing noise suppression capacitor 11 to be arranged closely. As a result, it is possible to reduce the volume of capacitor case 60 (frame portion 61), thereby enabling the power conversion device to be made smaller and less expensive.

[0056] Fifth Variant. In the above examples, four noise suppression capacitors are arranged in two rows and two columns. In this fifth modification, an example in which four noise suppression capacitors are arranged in a single row will be described. Fig. 10 is a plan view corresponding to Fig. 2 of the first embodiment, for explaining the configuration of a printed circuit board that forms a power conversion device according to the fifth modification, and similar to Fig. 9, the positions of the terminals are indicated by dashed circles.

[0057] 10, in the power conversion device (DC / DC converter 1) according to the fifth modified example, electrode patterns 55a to 55d are arranged in two rows and two columns on the surface of the printed circuit board 50. The four noise suppression capacitors 11 are arranged so that the line segments Lab, Lcd, Lef, and Lgh are parallel to one another, the terminals 12b, 12d, 12f, and 12h are on the same side, and they are connected to the housing 40 via the electrode patterns 55c and 55d.

[0058] This allows the pattern width of the electrode patterns 55a and 55b that connect the noise suppression capacitor 11 to the power conversion circuit 30 to be made shorter and wider, which makes it possible to reduce the temperature rise of the printed circuit board 50 around the noise suppression capacitor 11 and also allows it to be replaced with an inexpensive capacitor with a lower heat resistance temperature, thereby reducing the cost of the power conversion device.

[0059] Other aspects. In the above examples, one capacitor case 60 is provided for four noise suppression capacitors 11, but the present invention is not limited to this. For example, a capacitor case or annular frame may be provided for each pair of capacitors 11a and 11c, and for each pair of capacitors 11b and 11d.

[0060] This also allows the connection between the noise suppression capacitor 11 and the housing 40 to be as short as possible. This makes it possible to reduce the impedance from the other terminal of the noise suppression capacitor 11 to the housing 40, improving the filter performance in the high frequency band. This makes it possible to reduce the overall capacitance and number of noise suppression capacitors 11, thereby enabling the power conversion device to be made smaller and less expensive.

[0061] Although various exemplary embodiments and examples are described in this application, the various features, aspects, and functions described in one or more embodiments are not limited to the content disclosed in a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless modifications not illustrated are contemplated within the scope of the technology disclosed in this specification. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components disclosed in other embodiments.

[0062] As described above, the power conversion device (DC / DC converter 1) of the present application is configured to include: a power conversion circuit 30 formed using a plurality of semiconductor elements; a housing 40 that houses the power conversion circuit 30; a printed circuit board 50 on which an electrode pattern 55 is formed (for example, on a mounting surface 50fm); a noise-reduction capacitor 11 mounted on the printed circuit board 50 so that the main body portion rises from the printed circuit board 50, one of the terminals 12 protruding from the main body portion being electrically connected to the power conversion circuit 30 via the electrode pattern 55 and the other terminal 12 being electrically connected to the housing 40 via the electrode pattern 55; a case (capacitor case 60) that surrounds the main body portion and is open on the side away from the printed circuit board 50; a fixing member 72 (for example, a middle portion) that is fixed to the main body portion to fix the noise-reduction capacitor 11 to the case (capacitor case 60); and fastening members 8a, 8b that fix the printed circuit board 50 and the case (capacitor case 60) together with the housing 40. This makes it possible to obtain a power converter that ensures the vibration resistance of anti-noise capacitor 11 without requiring any additional members, and that can be made smaller and less expensive.

[0063] Furthermore, the connection point between the electrode pattern 55, to which the other terminal (electrically connected to the housing 40) of the electrode pattern 55 is connected, and the housing 40 is configured to be the same as the fixing point between the printed circuit board 50 and the case (capacitor case 60). This allows electrical connection and mechanical fixing to be achieved in a single process, reducing the number of steps.

[0064] In particular, if the fixing portion (for example, flange portion 62) of the case (capacitor case 60) to the printed circuit board 50 is configured to have a conductive portion (conductive members 63a, 63b) that provides electrical continuity from the surface facing the electrode pattern 55 to the opposite surface, mechanical stability is increased, and the electrical connection between the electrode pattern 55 and the fastening members 8a, 8b is improved, making it possible to form a good and shortest current path from the noise suppression capacitor 11 to the housing 40. Furthermore, additional members such as bus bars that would be required when the capacitor case is separate are no longer necessary, and it is possible to reduce the impedance up to the housing 40, improving filter performance in the high frequency band.

[0065] If the case (capacitor case 60) and the noise suppression capacitor 11 are arranged in the space formed between the printed circuit board 50 and the housing 40, the dead space can be made effective and the device can be made even more compact.

[0066] The noise suppression capacitor 11 is composed of a first capacitor whose first terminal corresponding to one terminal (connected to the power conversion circuit 30) is electrically connected to the positive side of the power conversion circuit 30, and a second capacitor whose first terminal corresponding to one terminal (connected to the power conversion circuit 30) is electrically connected to the negative side of the power conversion circuit 30. If the first capacitor and the second capacitor are configured so that the line segments (Lab and Lef, Lcd and Lgh) connecting the first terminal and the second terminal corresponding to the other terminal are aligned on a straight line and the first terminals or the second terminals face each other, the width of the electrode pattern 55 can be made wider, which reduces impedance and further improves filter performance in the high frequency band.

[0067] The noise suppression capacitor 11 is composed of a first capacitor whose first terminal corresponding to one terminal (connected to the power conversion circuit 30) is electrically connected to the positive side of the power conversion circuit 30, and a second capacitor whose first terminal (connected to the power conversion circuit 30) is electrically connected to the negative side of the power conversion circuit 30. If the first capacitor and the second capacitor are configured so that the line segments (Lab, Lef, Lcd, and Lgh) connecting the first terminal to the second terminal corresponding to the other terminal (electrically connected to the housing 40) are aligned in parallel with a distance from each other and the line segments connecting the first terminals to each other are parallel, the width of the electrode pattern 55 can be made short and wide, which reduces temperature rise and enables the use of inexpensive capacitors with a low heat resistance temperature.

[0068] The noise countermeasure capacitor 11 is formed by electrically connecting a plurality of capacitors 11a to 11d arranged in a plane parallel to the printed circuit board 50 (mounting surface 50fm), and the capacitor case 60 is configured to have partition walls (wall portions 61s) that separate the plurality of capacitors, thereby improving the placement accuracy of the noise countermeasure capacitor 11 and further improving vibration resistance due to the improved adhesion of the fixing member 72.

[0069] If the case (capacitor case 60) is configured to have a bottom plate portion 61b that separates the main body of the noise suppression capacitor 11 from the printed circuit board 50 (mounting surface 50fm), it is possible to improve the placement accuracy of the noise suppression capacitor 11. Furthermore, if the bottom plate portion 61b and the frame portion 61 are continuous, the shape stability of the frame portion 61 is improved.

[0070] If any of a positioning structure, a fitting structure, and a press-fit structure (for example, press-fit pins 68a, 68b and press-fit holes 57a, 57b) is formed between the printed circuit board 50 and the case (capacitor case 60), the ease of inserting the terminals 12 of the noise suppression capacitors 11 into the through holes of the printed circuit board 50 is improved, yield is improved, and manufacturing costs can be reduced. Furthermore, because the printed circuit board and the capacitor case 60 can be positioned even before the printed circuit board 50 is assembled into the housing 40, it is also possible to apply an adhesive at that stage, improving workability.

[0071] Of the portion (frame portion 61) surrounding the main body portion of the case (capacitor case 60), the portion (thick portion 61k) to which the fixing member 72 is fixed can be configured to be thicker than other portions, thereby improving the adhesion of the fixing member 72 to the capacitor case 60.

[0072] If the portion (thick portion 61k) to which the fixing member 72 is fixed is configured so that its thickness decreases from the portion corresponding to the base of the terminal 12 toward the printed circuit board 50 (mounting surface 50fm), interference between the solder and the capacitor case 60 can be more easily avoided, improving assembly ease and reducing manufacturing costs.

[0073] The fixing member 72 is configured so that both ends are fixed to two opposing points on either side of the main body of the part (frame portion 61) that surrounds the main body of the case (capacitor case 60), and the line connecting these two points is perpendicular to the line connecting one terminal (connected to the power conversion circuit 30) and the other terminal (electrically connected to the housing 40), thereby ensuring vibration resistance while reducing the amount of fixing member 72 used compared to fixing by filling.

[0074] Noise-suppression capacitor 11 is formed by electrically connecting a plurality of capacitor units, each of which is formed by electrically connecting a plurality of capacitors arranged in a plane parallel to printed circuit board 50, and by configuring printed circuit board 50 so that cases (capacitor cases 60) corresponding to each of the plurality of capacitor units are arranged, each capacitor unit can be handled individually.Therefore, even if the capacitance of each capacitor is reduced to improve high-frequency characteristics and the number of capacitors is increased, it is possible to avoid making the process more complicated.

[0075] If the case (capacitor case 60) is configured so that the side closer to the printed circuit board 50 is also open, the noise suppression capacitor 11 can be mounted on the printed circuit board regardless of whether the capacitor case 60 is attached to the printed circuit board 50 or not, thereby increasing the flexibility of the process.

[0076] Various aspects of the present disclosure are summarized below as appendices.

[0077] (Appendix 1) a power conversion circuit formed using a plurality of semiconductor elements; a housing that houses the power conversion circuit; a printed circuit board on which an electrode pattern is formed; a noise suppression capacitor mounted on the printed circuit board such that the main body portion rises from the printed circuit board, one of the terminals protruding from the main body portion being electrically connected to the power conversion circuit via the electrode pattern and the other terminal being electrically connected to the housing via the electrode pattern; a case that encloses the main body and is open on a side away from the printed circuit board; a fixing member that is fixed to the main body portion to fix the noise suppression capacitor to the case; and a fastening member for fastening the printed circuit board and the case together with the housing; A power conversion device comprising:

[0078] (Appendix 2) The power conversion device described in Appendix 1, characterized in that the connection point between the electrode pattern to which the other terminal of the electrode pattern is connected and the housing is the same point as the fixed point between the printed circuit board and the case.

[0079] (Appendix 3) The power conversion device described in Appendix 2, characterized in that a conductive portion is formed in the fixed portion of the case to the printed circuit board, providing electrical continuity from the surface facing the electrode pattern to the opposite surface.

[0080] (Appendix 4) 4. The power conversion device according to any one of claims 1 to 3, wherein the case and the noise suppression capacitor are arranged in a space formed between the printed circuit board and the housing.

[0081] (Appendix 5) the noise suppression capacitor includes a first capacitor having a first terminal corresponding to the one terminal electrically connected to a positive electrode side of the power conversion circuit, and a second capacitor having the first terminal electrically connected to a negative electrode side of the power conversion circuit, 5. The power conversion device according to any one of appendixes 1 to 4, wherein the first capacitor and the second capacitor are arranged in a plane parallel to the printed circuit board such that a line segment connecting the first terminal and a second terminal corresponding to the other terminal is aligned on a straight line, and the first terminals or the second terminals face each other.

[0082] (Appendix 6) the noise suppression capacitor includes a first capacitor having a first terminal corresponding to the one terminal electrically connected to a positive electrode side of the power conversion circuit, and a second capacitor having the first terminal electrically connected to a negative electrode side of the power conversion circuit, 5. The power conversion device according to any one of appendixes 1 to 4, wherein the first capacitor and the second capacitor are arranged in a plane parallel to the printed circuit board such that line segments connecting the first terminal and a second terminal corresponding to the other terminal are aligned parallel to each other at a distance, and line segments connecting the first terminals to each other are parallel to line segments connecting the second terminals to each other.

[0083] (Appendix 7) the noise suppression capacitor is configured by electrically connecting a plurality of capacitors arranged in a plane parallel to the printed circuit board, 7. The power conversion device according to claim 1, wherein the case has partition walls that separate the plurality of capacitors.

[0084] (Appendix 8) 8. The power conversion device according to claim 1, wherein the case has a bottom plate portion that separates the main body portion from the printed circuit board.

[0085] (Appendix 9) Between the printed circuit board and the case 9. The power conversion device according to any one of claims 1 to 8, comprising one of a positioning structure, a fitting structure, and a press-fit structure.

[0086] (Appendix 10) A power conversion device described in any one of appendices 1 to 9, characterized in that the portion of the case surrounding the main body portion to which the fixing member is fixed is formed thicker than other portions.

[0087] (Appendix 11) The power conversion device described in Appendix 10, characterized in that the portion to which the fixing member is fixed has a thickness that decreases from the portion corresponding to the base of the terminal toward the printed circuit board, in terms of height from the printed circuit board.

[0088] (Appendix 12) The fixing member has two ends fixed to two opposing positions on the side of the main body portion of the case, the two ends being located at positions on the side of the main body portion, the fixing member being located at two opposing positions on the side of the main body portion of the case, 12. The power conversion device according to any one of claims 1 to 11, wherein the line segment connecting the two locations is perpendicular to the line segment connecting the one terminal and the other terminal.

[0089] (Appendix 13) the noise suppression capacitor is configured by electrically connecting a plurality of capacitor units, each of which is configured by electrically connecting a plurality of capacitors arranged in a plane parallel to the printed circuit board; 13. The power conversion device according to any one of claims 1 to 12, wherein the cases provided corresponding to the plurality of capacitor units are arranged on the printed circuit board.

[0090] (Appendix 14) The power conversion device according to any one of claims 1 to 7 and 9 to 13, wherein the case is also open on the side closer to the printed circuit board. [Explanation of symbols]

[0091] 1: DC / DC converter (power conversion device), 10: noise suppression capacitor circuit, 11: noise suppression capacitor, 11a, 11b, 11c, 11d: capacitor, 12, 12a, 12b, 12c, 12d, 12e, 12f, 12g, 12h: terminal, 20: smoothing capacitor, 30: power conversion circuit, 31: inverter circuit, 31a, 31b, 31c, 31d: semiconductor switching element, 32: transformer, 33: rectifier circuit, 33a, 33b: rectifier element, 34: smoothing reactor, 35: smoothing capacitor, 36: control circuit, 40: housing, 50: printed circuit board, 50fm: mounting surface, 51: substrate, 55, 55a, 55b, 55c, 55d, 55e, 55f: electrode pattern, 56a, 56b: through holes, 57a, 57b: press-fit holes, 58a, 58b: through holes, 60: capacitor case (case), 61: frame portion, 61fu: upper end surface (end surface), 61k: thick portion, 62, 62a, 62b: flange portion, 63a, 63b: conductive member (conductive portion), 8a, 8b: fastening member, 68a, 68b: press-fit pin, 72, 72a, 72b: fixing member, 91: input power supply, 92: external load, 93: output power supply, Lab, Lcd, Left, Lgh: line segment.

Claims

1. a power conversion circuit formed using a plurality of semiconductor elements; a housing that houses the power conversion circuit; a printed circuit board on which an electrode pattern is formed; a noise suppression capacitor mounted on the printed circuit board such that the main body portion rises from the printed circuit board, one of the terminals protruding from the main body portion being electrically connected to the power conversion circuit via the electrode pattern and the other terminal being electrically connected to the housing via the electrode pattern; a case that encloses the main body and is open on a side away from the printed circuit board; a fixing member that is fixed to the main body portion to fix the noise suppression capacitor to the case; and a fastening member for fastening the printed circuit board and the case together with the housing; A power conversion device comprising:

2. 2. The power conversion device according to claim 1, wherein a connection point between the electrode pattern to which the other terminal of the electrode pattern is connected and the housing is the same as a fixed point between the printed circuit board and the case.

3. 3. The power conversion device according to claim 2, wherein a conductive portion is formed in a portion of the case that is fixed to the printed circuit board, the conductive portion providing electrical continuity from a surface facing the electrode pattern to a surface opposite the surface.

4. 4. The power conversion device according to claim 1, wherein the case and the noise suppression capacitor are arranged in a space formed between the printed circuit board and the housing.

5. the noise suppression capacitor includes a first capacitor having a first terminal corresponding to the one terminal electrically connected to a positive electrode side of the power conversion circuit, and a second capacitor having the first terminal electrically connected to a negative electrode side of the power conversion circuit, 4. The power conversion device according to claim 1, wherein the first capacitor and the second capacitor are arranged in a plane parallel to the printed circuit board such that a line segment connecting the first terminal and the second terminal corresponding to the other terminal is aligned on a straight line, and the first terminals or the second terminals face each other.

6. the noise suppression capacitor includes a first capacitor having a first terminal corresponding to the one terminal electrically connected to a positive electrode side of the power conversion circuit, and a second capacitor having the first terminal electrically connected to a negative electrode side of the power conversion circuit, 4. The power conversion device according to claim 1, wherein the first capacitor and the second capacitor are arranged in a plane parallel to the printed circuit board such that line segments connecting the first terminal and a second terminal corresponding to the other terminal are arranged in parallel with a distance from each other, and line segments connecting the first terminals to each other are parallel to line segments connecting the second terminals to each other.

7. the noise suppression capacitor is configured by electrically connecting a plurality of capacitors arranged in a plane parallel to the printed circuit board, 4. The power conversion device according to claim 1, wherein the case has partition walls that separate the plurality of capacitors.

8. 4. The power conversion device according to claim 1, wherein the case has a bottom plate portion that separates the main body portion from the printed circuit board.

9. Between the printed circuit board and the case 4. The power converter according to claim 1, wherein the power converter has one of a positioning structure, a fitting structure, and a press-fit structure.

10. 4. The power conversion device according to claim 1, wherein a portion of the case surrounding the main body to which the fastening member is fastened is formed thicker than other portions.

11. The power conversion device according to claim 10, wherein the thickness of the portion to which the fixing member is fixed decreases from a portion corresponding to a base portion of the terminal toward the printed circuit board.

12. The fixing member has two ends fixed to two opposing positions on the side of the main body portion of the case, the two positions being located at opposite sides of the main body portion, 4. The power conversion device according to claim 1, wherein the line segment connecting the two locations is perpendicular to the line segment connecting the one terminal and the other terminal.

13. the noise suppression capacitor is configured by electrically connecting a plurality of capacitor units, each of which is configured by electrically connecting a plurality of capacitors arranged in a plane parallel to the printed circuit board; 4. The power conversion device according to claim 1, wherein the cases provided corresponding to the plurality of capacitor units are arranged on the printed circuit board.

14. 4. The power conversion device according to claim 1, wherein the case is also open on a side closer to the printed circuit board.

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