Power converter

Abstract

Power converter (1) with: a switching circuit (20); a capacitor module (3) which is electrically connected to the switching circuit; an auxiliary capacitor module (5) connected in parallel to the capacitor module; and a device housing (12) which contains the switching circuit, the capacitor module and the auxiliary capacitor module, wherein The capacitor module includes: a capacitor element (31), a capacitor housing (32) that contains the capacitor element, an encapsulation resin (33) that encapsulates the capacitor element in the capacitor housing, and a capacitor busbar (4) which connects the capacitor element to a power terminal of the switching circuit, wherein the capacitor busbar includes: an element connection section (41) that is connected to the capacitor element within the encapsulation resin, a connecting section (42) which is connected to the power connection outside the encapsulation resin, and a power supply connection section (43) which is connected to a power supply wiring (54) outside the encapsulation resin, wherein the power supply wiring is electrically connected to a DC power supply, wherein the capacitor busbar includes a DC path (44) which represents a current path between the terminal connection section and the power supply connection section, and the DC path is exposed to the outside of the encapsulation resin, the auxiliary capacitor module is connected to the power supply connection section of the capacitor busbar, the auxiliary capacitor module is detachably attached to the power supply connection section by means of a fastening element (11), and a fastening direction of a fastening element (135) that secures the auxiliary capacitor module and a fastening direction of the fixing element are the same.

Description

Technical field

[0001] The present disclosure relates to power converters comprising a switching circuit and a capacitor module. Background technology

[0002] For example, a power converter such as an inverter, which is provided for electric and hybrid cars, comprises a switching circuit and a capacitor module. JP 2014 - 207 427 A discloses a capacitor module that encapsulates capacitor elements with an encapsulating resin. According to the aforementioned disclosure, the capacitor module is connected to the switching circuit via a busbar (hereinafter referred to as the capacitor busbar).

[0003] In addition to the capacitor elements and the switching circuit, the capacitor busbar is also electrically connected to a DC power supply. This means that the capacitor busbar serves as a current path between the DC power supply and the switching circuit, a current path between the DC power supply and the capacitor, and a current path between the capacitor and the switching circuit.

[0004] Furthermore, US 2007 / 0 109 715 A1 discloses a capacitor module with multiple capacitors, wherein a laminate comprises a first flat section enclosing the multiple capacitors held on it and electrically connected to it, a second flat section continuous with the first flat section and extending in a direction away from the multiple capacitors held on the first flat section, and connecting sections formed at the ends of the first and second flat sections and electrically connected to the outside. JP 2016-158 358 A describes a semiconductor element in which a power terminal protrudes from a body part and is connected to a busbar. An element heat sink is electrically connected to the semiconductor element and a power terminal. The element heat sink radiates the heat generated by the semiconductor element.A busbar heat sink is positioned so that, from the perspective of the element heat sink's thickness, it does not overlap with the semiconductor element. The busbar heat sink is connected to the power terminal and dissipates the heat transferred from the busbar via the power terminal. Further prior art is known from JP 2012 - 249 480 A, DE 11 2016 000 499 T5 and DE 10 2016 103 785 A1. Summary of the invention

[0005] The power converter disclosed in JP 2014 - 207 427 A has the following problems.

[0006] Since power converters with higher power outputs have been developed in recent years, there is a trend towards increasing the current flowing from the DC power supply to the switching circuit. This likely increases the amount of heat generated in the capacitor busbar.

[0007] In the power converter disclosed in JP 2014-207427A, part of the capacitor busbar is located within the encapsulation resin of the capacitor module. A section of the capacitor busbar connected to the switching circuit and a section connected to the DC power supply protrude from different parts of the encapsulation resin. Thus, the current flowing from the DC power supply to the switching circuit temporarily passes through the encapsulation resin of the capacitor module. If a large current flows through this current path, the dissipation of heat resulting from the current may be adversely affected. Furthermore, the amount of heat transferred to the capacitor elements is likely to increase, potentially raising their temperature.

[0008] The purpose of the present disclosure is to provide a power converter and a capacitor module in which heat from a capacitor busbar is simply and efficiently dissipated and the increase in temperature of capacitor elements is simply prevented.

[0009] The problem is solved according to the invention by a power converter according to claim 1 and alternatively by a power converter according to claim 4. Further features and advantageous embodiments are shown in the dependent claims.

[0010] One aspect of the present disclosure provides a power converter comprising a switching circuit, a capacitor module electrically connected to the switching circuit, an auxiliary capacitor module connected in parallel to the capacitor module, and a device housing containing the switching circuit, the capacitor module, and the auxiliary capacitor module. The capacitor module is electrically connected to the switching circuit. The capacitor module comprises a capacitor element, a capacitor housing, an encapsulating resin, and a capacitor busbar. The capacitor housing contains the capacitor element. The encapsulating resin encapsulates the capacitor element within the capacitor housing. The capacitor busbar connects the capacitor element to a power terminal of the switching circuit.The capacitor busbar comprises an element connection section, a terminal connection section, and a power supply connection section. The element connection section is connected to the capacitor element within the encapsulation resin. The terminal connection section is connected to the power terminal outside the encapsulation resin. The power supply connection section is connected to power supply wiring outside the encapsulation resin. The power supply wiring is electrically connected to a DC power supply. The capacitor busbar includes a DC path, which is a current path between the terminal connection section and the power supply connection section. The DC path is exposed to the outside of the encapsulation resin.The auxiliary capacitor module is connected to the power supply connection section of the capacitor busbar, the auxiliary capacitor module is detachably attached to the power supply connection section by a fastening element, and the fastening direction of a fastening element that secures the auxiliary capacitor module and the fastening direction of the fastening element are the same.

[0011] According to one aspect of the power converter, the DC path, which represents the current path between the terminal block and the power supply terminal block in the capacitor busbar, is exposed on the outside of the encapsulating resin. When a large current flows through the DC path extending from the power supply terminal block to the terminal block, the heat generated by the current is efficiently dissipated. This prevents the heat generated in the DC path from becoming trapped within the encapsulating resin of the capacitor module. Consequently, an increase in the temperature of the capacitor element is effectively prevented.

[0012] Each plate-like part comprises a specific section or sub-area that has a thickness less than that of the surrounding area or section. Thus, the plate-like part has increased electrical resistivity at and around this specific section or sub-area. This specific section or sub-area is located in the region of each plate-like part that is closer to the power supply connection section than to the terminal connection section. Therefore, the electrical resistivity of the portion of each plate-like part that is closer to the power supply connection section than to the terminal connection section is increased. The DC component of the DC current flowing into the power supply connection section is thus easily conducted to the terminal connection section.Consequently, it is simply prevented that the DC component of the DC current, which has flowed into the plate-like part via the power supply connection section, flows towards the capacitor busbar in the encapsulation resin.

[0013] As described above, the aforementioned aspects provide power converters in which the heat from the busbar is simply and efficiently dissipated and the increase in the temperature of the capacitor element is simply prevented. Brief description of the drawings

[0014] The aforementioned and further tasks, features and advantages of this disclosure will become clearer by reference to the following description, which is made in conjunction with the accompanying drawings, for which the following applies: Fig. 1 is an explanatory top view of a power converter according to a first embodiment; Fig. Figure 2 is an explanatory top view of the power converter according to the first embodiment from the perspective of the opposite side of the view from Fig. 1; Fig. Figure 3 is a perspective view of a capacitor module according to the first embodiment; Fig. 4 is a cross-sectional view, shown in the direction of arrows along line IV-IV in Fig. 3 is taken; Fig. 5 is a cross-sectional view, which is shown in the direction of arrows along line VV in Fig. 4 is taken; Fig. 6 is a cross-sectional view, shown in the direction of arrows along line VI-VI in Fig. 4 has been taken. Fig. 7 is a view of VII in Fig. 3; Fig. 8 is a view of VIII in Fig. 3; Fig. 9 is a circuit diagram of the power converter according to the first embodiment; Fig. Figure 10 is an explanatory cross-sectional view of an auxiliary / additional capacitor module according to the first embodiment; Fig. Figure 11 is an explanatory illustration showing a current path in a capacitor busbar (positive electrode busbar) according to the first embodiment; Fig. Figure 12 is an explanatory illustration showing a current path in a capacitor busbar (negative electrode busbar) according to the first embodiment; Fig. Figure 13 is a top view of a capacitor module according to a second embodiment, which is an unclaimed comparative example; Fig. Figure 14 is a rear view of the capacitor module according to the second embodiment; Fig. Figure 15 is a side view of the capacitor module according to the second embodiment; Fig. Figure 16 is a cross-sectional view, shown in the direction of arrows along line XVI-XVI in Fig. 13 is taken, illustrating the capacitor busbar and an insulating layer; Fig. Figure 17 is a top view of the capacitor module according to the second embodiment, which is an unclaimed comparative example without an encapsulation resin and a capacitor housing; Fig. Figure 18 is a top view of a capacitor busbar according to a third embodiment, which is an unclaimed comparative example; Fig. Figure 19 is a top view of a capacitor busbar according to a fourth embodiment, which is an unclaimed comparative example; Fig. Figure 20 is a top view of a capacitor busbar according to a fifth embodiment, which is an unclaimed comparative example; and Fig. Figure 21 is a cross-sectional view of a capacitor busbar and an insulating layer according to a further embodiment, which is an unclaimed comparative example, and which corresponds to the cross-sectional view of Fig. 16 corresponds to this. Description of the exemplary implementations

[0015] The first embodiment described below illustrates one embodiment of the claimed invention. The further embodiments shown (i.e., the second to fifth and a further embodiment) relate to unclaimed comparative examples. First embodiment

[0016] A power converter according to an exemplary embodiment is described with reference to Fig. 1 to 12 described.

[0017] As it is in Fig. 1 and Fig. As shown in Figure 2, a power converter 1 of the present embodiment comprises a switching circuit 20 and a capacitor module 3, which is electrically connected to the switching circuit 20.

[0018] As it is in Fig. As shown in Figures 3 to 8, the capacitor module comprises three capacitor elements 31, a capacitor housing 32, an encapsulating resin 33, and capacitor busbars 4. The capacitor housing 32 contains the capacitor elements 31. The encapsulating resin 33 encapsulates or surrounds the capacitor elements 31 within the capacitor housing 32. The capacitor busbars 4 connect the capacitor elements 31 to power terminals 21 of the switching circuit 20 (see Figure 3 to 8). Fig. 1).

[0019] As it is in Fig. 4 and Fig. As shown in Figure 5, each capacitor busbar 4 comprises an element connection section 41, terminal connection sections 42, and a power supply connection section 43. The element connection section 41 is connected to the capacitor elements 31 within the encapsulation resin 33. The terminal connection sections 42 are sections that are to be connected to the power terminals 21 outside the encapsulation resin 33. The power supply connection section 43 is connected to a power supply wiring system, which is electrically connected to the DC power supply, outside the encapsulation resin 33. In the present embodiment, the power supply wiring system comprises auxiliary / supplementary busbars 54, which are discussed below (see Figure 5). Fig. 2).

[0020] As it is in Fig. As shown in Figures 1 to 4, each capacitor busbar 4 comprises a DC path 44 that configures a current path between the terminal connection sections 42 and the power supply connection section 43. The DC path 44 is exposed on the outside of the encapsulation resin 33.

[0021] The power converter 1 of the present embodiment is installed in a vehicle such as an electric car or a hybrid car and is connected between a DC power supply BAT and a rotating AC machine MG, as shown in the circuit diagram of Fig. Figure 9 shows that the power converter 1 is configured to convert power between DC power and AC power by switching the switching circuit 20.

[0022] The switching circuit 20 comprises semiconductor modules 2, each equipped with switching elements 2u and 2d. The semiconductor modules 2 are stacked with cooling tubes or lines 22, as shown in Fig. 1 and Fig. Figure 2 shows that the cooling pipes or lines 22 each comprise a refrigerant flow channel. The refrigerant flow channels of the cooling pipes or lines 22 are coupled to each other.

[0023] In each semiconductor module 2, the power terminal 21 projects in a direction orthogonal to a stacking direction X. The terminal connection sections 42 of each capacitor busbar 4 are connected to these power terminals 21. Hereinafter, the stacking direction X is also simply referred to as an X-direction. The projection direction of the power terminals 21 is referred to as a Z-direction, as needed, and the direction orthogonal to both the X-direction and the Z-direction is referred to as a Y-direction, as needed.

[0024] The semiconductor modules 2 are located in the Y-direction next to the capacitor module 3. The capacitor module 3 has an elongated shape extending in the X-direction. The stack of semiconductor modules 2 (namely, the switching circuit 20) is positioned opposite the capacitor module 3 in the Y-direction along a region that represents essentially half the length of the capacitor module 3. The capacitor module 3 is positioned such that an opening 321 of the capacitor housing 32 is opposite the switching circuit 20 in the Y-direction. That is, a potting surface of the encapsulating resin 33 is opposite the switching circuit 20 in the Y-direction.

[0025] Each semiconductor module 2 is equipped or configured with switching elements that are an upper-arm switching element 2u and a lower-arm switching element 2d, as shown in Fig. Figure 9 shows the upper arm switching element 2u and the lower arm switching element 2d connected in series. The high-potential sides of the upper arm switching element 2u are connected to positive electrode power terminals 21, and the low-potential sides of the lower arm switching element 2d are connected to negative electrode power terminals 21. The connecting section between the upper arm switching element 2u and the lower arm switching element 2d is connected to an AC output terminal (not illustrated). The AC terminals are connected to the rotating electric machine MG.

[0026] As it is in Fig. As shown in Figures 3 to 9, the capacitor busbars 4 comprise a positive electrode busbar 4P and a negative electrode busbar 4N, which are connected to opposite electrodes of the capacitor elements 31. The connection sections 42 of the positive electrode busbar 4P are connected to the positive electrode power terminals 21, and the connection sections 42 of the negative electrode busbar 4N are connected to the negative electrode power terminals 21. Additionally, the power supply connection section 43 of the positive electrode busbar 4P is electrically connected to the positive electrode of the DC power supply BAT, and the power supply connection section 43 of the negative electrode busbar 4N is electrically connected to the negative electrode of the DC power supply BAT.

[0027] The power converter 1 comprises, as described in Fig. 1, Fig. 2 and Fig. Figure 9 shows an auxiliary or supplementary capacitor module 5, which is connected in parallel to the capacitor module 3. The auxiliary capacitor module 5 is connected to the power supply connection sections 43 of the capacitor busbars 4. Thus, the capacitor module 3 and the auxiliary capacitor module 5 are connected in parallel to each other. As shown in Fig. As shown in Figure 2, the auxiliary capacitor module 5 is attached to the power supply connection sections 43 by means of fastening elements 11 in a detachable / separable manner.

[0028] As it is in Fig. 1 and Fig. As shown in Figure 2, the auxiliary capacitor module 5 is located next to the capacitor module 3 in the Y direction and next to the switching circuit 20 in the X direction.

[0029] As it is in Fig. As shown in Figure 10, the auxiliary capacitor module 5 is also equipped with capacitor elements 51, which are located within a capacitor housing 52, as is the case with the capacitor module 3. The capacitor elements 51 are encapsulated within the capacitor housing 52 by an encapsulating resin 53. The capacitor housing 52 includes an opening 521, which is opposite the capacitor module 3 in the Y-direction. This means that the auxiliary capacitor module 5 is positioned such that a potting surface of the encapsulating resin 53 is opposite the capacitor module 3 in the Y-direction.

[0030] The auxiliary capacitor module 5 comprises a pair of auxiliary busbars 54. This pair of auxiliary busbars 54 is connected to a pair of electrodes of each capacitor module 51. The auxiliary busbars 54 extend on the outer surface of the capacitor housing 52. A positive-side auxiliary busbar 54P projects from the opening 521 of the capacitor housing 52 and extends onto the outer surface of the capacitor housing 52. Although this in Fig. As not shown in Figure 10, a negative-side auxiliary busbar 54N also protrudes from the opening 521 and extends equally onto the outer surface of the capacitor housing 52. As shown in Fig. As shown mainly by a dashed line in Figure 2, the auxiliary busbar 54N comprises a Y-direction extension section 54Ny extending in the Y direction. The Y-direction extension section 54Ny overlaps the positive-side auxiliary busbar 54P in the thickness direction while being insulated from it. The auxiliary busbar 54N comprises an X-direction extension section 54Nx that overlaps a portion of the Y-direction extension section 54Ny and is connected to it. The X-direction extension section 54Nx is located on the outer surface of the capacitor housing 52, thus extending in the X direction. In this embodiment, the Y-direction extension section 54Ny and the X-direction extension section 54Nx are formed by separate elements.

[0031] As it is in Fig. 2 and Fig. As shown in Figure 9, the power supply connection sections 43 of the capacitor busbars 4 are connected to the DC power supply BAT via the auxiliary busbars 54. This means that each auxiliary busbar 54, at one end, includes a first connection section 541, which is connected to the associated capacitor busbar 4. The first connection section 541 is connected to the power supply connection section 43 of the associated capacitor busbar 4 via the associated fixing element 11. Each auxiliary busbar 54 also includes a second connection section 542 at the other end. The connecting wiring from the DC power supply BAT is connected to the second connection section 542.

[0032] The line converter 1 comprises a device housing 12, which contains the switching circuit 20, the capacitor module 3, and the auxiliary capacitor module 5. As shown in Fig. As shown in Figure 1, the capacitor module 3 is attached to the device or equipment housing 12 by means of fastening elements 133. As shown in Fig. As shown in Figure 2, the auxiliary capacitor module 5 is attached to the device housing 12 by means of fastening elements 135.

[0033] The fastening direction of the fasteners 135, which secure the auxiliary capacitor module 5, and the fastening direction of the fixing elements 11 are the same. That is, the fasteners 135 and the fixing elements 11 are oriented from the front to the back of the sheet. Fig. 2 are fixed. The fastening direction of the fastening elements 133, which secure the capacitor module 3, as shown in Fig. As shown in Figure 1, the direction of fastening of the fasteners 135 and the fixing elements 11 is opposite to that shown.

[0034] In the present embodiment, both the fastening elements 11 and the fastening elements 133 and 135 can be screws or pins / bolts.

[0035] As described above, the capacitor module 3 comprises the capacitor busbars 4, which are the positive electrode busbar 4P and the negative electrode busbar 4N. As described in Fig. 5 and Fig. As shown in Figure 6, the positive electrode busbar 4P and the negative electrode busbar 4N each comprise an opposing section 45 on a portion of their respective DC paths 44. The opposing sections 45 are oriented opposite each other in the thickness direction, with the insulating layer 46 lying between them. In the thickness direction (Z-direction in the present embodiment), the power supply connection section 43 projects from the opposing section 45 and the insulating layer 46. The power supply connection section 43 projects from the opposing section 45 and the insulating layer 46 in the X-direction to one side.

[0036] The overlapping section 45 comprises a flat or planar, plate-like main overlapping section 451 and an upright overlapping section 452. The upright overlapping section 452 extends upright or perpendicularly from the main overlapping section 451 in the thickness direction of the main overlapping section 451 (i.e., in the Z-direction). The insulation layer 46 comprises a main insulation section 461 and an upright insulation section 462. The main insulation section 461 is located between the pair of main overlapping sections 451. The upright insulation section 462 is located between the pair of upright overlapping sections 452.

[0037] The power supply connection section 43 is angled or bent relative to the upright opposing section 452 in the thickness direction of the upright opposing section 452 (namely in the X-direction). The power supply connection section 43 is designed such that it is parallel to the main opposing section 451. The fact that the power supply connection section 43 and the main opposing section 451 are parallel to each other means that the thickness direction of the power supply connection section 43 is essentially the same as the thickness direction of the main opposing section 451. The insulation layer 46 is formed from a resin molded body.

[0038] As it is in Fig. 4, Fig. 7 and Fig. As shown in Figure 8, the main opposing section 451 comprises an elongated opposing section 451a extending in the X-direction and a projecting opposing section 451b projecting from the end of the elongated opposing section 451a in the X-direction, extending away from the capacitor elements 31 in the Y-direction. The connecting sections 42 project from the elongated opposing section 451a to the side furthest from the capacitor elements 31 in the Y-direction. The upright opposing section 452 extends upright or perpendicularly with respect to the edge of the projecting opposing section 451b that is furthest from the connecting sections 42 in the Y-direction.

[0039] A discharge substrate 36 is located on a portion of the region or area of ​​the capacitor module 3 in the X-direction where the capacitor busbar 4 does not protrude. The discharge substrate 36 is electrically connected to the capacitor elements 31 in the capacitor module 3. The discharge substrate 36 is configured to discharge electrical charge stored in the capacitor module 3.

[0040] Next, the operational advantages of the present embodiment will be described.

[0041] In the power converter 1, the DC path 44, which represents the current path between the connection sections 42 and the power supply connection section 43 in each capacitor busbar 4, is exposed on the outside of the encapsulation resin 33. When a large current flows through the DC paths 44 extending from the power supply connection section 43 to the connection sections 42, as is the case in Fig. 11 and Fig. As shown in Figure 12, heat caused by the current is therefore efficiently dissipated. This prevents the heat generated in the DC paths 44 from being trapped or enclosed in the encapsulation resin 33 of the capacitor module 3. As a result, the temperature increase of the capacitor elements 31 is effectively prevented.

[0042] For example, while driving the vehicle using the rotating electric machine MG, a large current sometimes flows through the DC paths 44 between the DC power supply BAT and the switching circuit 20 (see arrows i in Fig. 11 and Fig. 12) At this time, the DC paths 44 generate heat. If the DC paths 44 are located inside the encapsulation module 33, heat dissipation is prevented, which could lead to an increase in the temperature of the capacitor elements 31. In contrast, as described above, the DC paths 44 are located outside the encapsulation module 33. Thus, the heat from the DC path 44 is easily dissipated, preventing an increase in the temperature of the capacitor elements 31.

[0043] The power converter 1 includes the auxiliary capacitor module 5, which is connected to the power supply connection sections 43 of the capacitor busbars 4. Thus, the capacitor module 3 and the auxiliary capacitor module 5 are connected to each other via the capacitor busbars 4. Consequently, the current paths between the capacitor module 3 and the auxiliary capacitor module 5 are short. This reduces the inductance difference between the capacitor elements 31 and 51, thereby reducing current resonance between them. As a result, heat generation in the capacitor elements 31 and 51 is prevented.

[0044] The auxiliary capacitor module 5 is detachably / removably attached to the power supply connection sections 43 by means of the fastening elements 11. This allows for easy replacement of the auxiliary capacitor module. In other words, the auxiliary capacitor module 5 is simply disconnected from the capacitor module 3 and the switching circuit 20. Therefore, it is easy, for example, to replace only the auxiliary capacitor module 5.

[0045] The fastening direction of the fastening elements 135, which secure the auxiliary capacitor module 5 to the device housing 12, is the same as the fastening direction of the fixing elements 11, which secure the auxiliary capacitor module 5 to the power supply connection sections 43. This makes it easy to install or replace the auxiliary capacitor module 5.

[0046] The positive electrode busbar 4P and the negative electrode busbar 4N each comprise the opposing section 45 on a portion of their respective DC paths 44. The opposing sections 45 are oriented opposite each other in the thickness direction, with the insulating layer 46 between them. In the thickness direction, the power supply connection sections 43 project from the opposing sections 45 and the insulating layer 46. Connecting the power supply connection sections 43 thus effectively prevents the stress applied to the power supply connection sections 43 from being transferred to the encapsulation resin 33. This prevents problems such as the formation of fractures or cracks in portions of the encapsulation resin 33 where the capacitor busbars 4 protrude.

[0047] The opposing sections 45 each comprise the main opposing sections 451 and the upright opposing sections 452, and the insulation layer 46 comprises the main insulation section 461 and the upright insulation section 462. Each power supply connection section 43 is angled or bent with respect to the upright opposing section 452 in the thickness direction of the upright opposing section 452 and is configured so that it is parallel to the main opposing section 451. This configuration more efficiently prevents the load or pressure / stress applied to the power supply connection sections 43 from being transferred to the encapsulation resin 33.

[0048] As described above, the present embodiment provides the power converter in which the heat from the busbars is simply and efficiently dissipated and the increase in temperature of the capacitor elements is simply prevented. Second embodiment

[0049] An embodiment of the capacitor module 3 is described with reference to Fig. Described in sections 13 to 17.

[0050] As it is in Fig. As shown in Figures 13 to 15 and 17, the capacitor module 3 of the present embodiment comprises the capacitor elements 31, the encapsulating resin 33, and the pair of capacitor busbars 4. The encapsulating resin 33 encapsulates the capacitor elements 31. The pair of capacitor busbars 4 are connected to the capacitor elements 31. Each capacitor busbar 4 comprises an exposed portion 40, which is exposed with respect to the encapsulating resin 33. Each exposed portion 40 comprises a plate-like portion 401, the power supply connection section 43, and the connection sections 42. The power supply connection sections 43 extend from the plate-like portion 401 and are electrically connected to the power supply.The connection sections 42 extend from the plate-like part 401 and are electrically connected to other electronic components (in the present embodiment, semiconductor modules described below). Each plate-like part 401 comprises a specific part or sub-area 404 in the region that is closer to the power supply connection section 43 than to the connection sections 42. The specific part or sub-area 404 has a thickness that is less than that of the surrounding area or section.

[0051] The background technology will now be described in relation to the present embodiment.

[0052] Japanese patent publication no. 2014-45035 discloses a capacitor that forms part of a power converter, such as an inverter, which is to be installed, for example, in electric and hybrid cars. The capacitor disclosed in the aforementioned patent literature has the function of smoothing a DC voltage applied to semiconductor modules, each of which is formed by resin casting / molding semiconductor elements that constitute a power conversion circuit.

[0053] The capacitor disclosed in the aforementioned patent literature comprises capacitor elements in a capacitor housing, and the capacitor elements are encapsulated by an encapsulating resin. A pair of busbars is connected to pairs of electrodes of the capacitor elements. Each busbar includes a power supply input terminal connected to the power supply and connection sections connected to the semiconductor modules. The power supply input terminals and the connection sections of the busbars are exposed to the encapsulating resin. Each power supply input terminal and its associated connection sections are electrically interconnected within the encapsulating resin.

[0054] The direct current flowing from the power supply to the capacitor includes a ripple component that passes through the capacitor elements and a direct current component that does not. The direct current component does not pass through the capacitor elements but flows from the power supply input terminal, via the busbar located within the encapsulating resin, to the connection sections.

[0055] Next, problems that can be solved by the capacitor module 3 of the present embodiment will be described.

[0056] In the capacitor disclosed in the aforementioned patent literature, the DC component of the input DC also flows through the busbar located within the encapsulation resin, in addition to the ripple component. Therefore, it is likely that the amount of heat generated in the busbar within the encapsulation resin will increase, and this heat from the busbar may potentially affect the capacitor elements. Furthermore, if the busbar encapsulated within the resin generates heat, it is likely that this heat will become trapped within the resin and be prevented from dissipating. Therefore, it is not preferred for the busbar to generate heat within the encapsulation resin.

[0057] The present embodiment was created in consideration of the aforementioned problems and provides a capacitor in which it is simply prevented that the busbars generate heat in the encapsulation resin.

[0058] The present embodiment will now be described in detail.

[0059] Capacitor module 3 forms part of a power converter. This power converter can be installed in a vehicle, such as electric and hybrid cars. It is located between the DC power supply and a three-phase AC motor. Capacitor module 3 smooths the DC voltage applied by the DC power supply and outputs the smoothed DC voltage to the switching circuit. The switching circuit then converts the DC voltage into an AC voltage. This AC voltage is applied to the three-phase AC motor.

[0060] The capacitor elements 31 are housed or accommodated in the capacitor housing 32, as shown in Fig. Figures 13 to 15 show that the capacitor housing 32 is shaped like a rectangular box with one side open. Viewed in the direction in which the capacitor housing 32 is open, it has a rectangular shape. Hereinafter, the direction in which the capacitor housing 32 is open is referred to as the Y-direction, the longitudinal direction of the capacitor housing 32 as seen in the Y-direction is referred to as the X-direction, and the transverse direction of the capacitor housing 32 as seen in the Y-direction is referred to as the Z-direction. The Y-direction, the X-direction, and the Z-direction are orthogonal to each other.

[0061] As it is in Fig. As shown in Figure 15, the capacitor housing 32 is filled with the encapsulating resin 33, which encapsulates or surrounds the capacitor elements 31. The encapsulating resin 33 can, for example, be a thermosetting or heat-curing resin such as an epoxy resin. The encapsulating resin 33 comprises a resin surface 331, which is exposed with respect to or at an opening 322 of the capacitor housing 32. The resin surface 331 is orthogonal to the Y-direction.

[0062] As it is in Fig. 13 and Fig. As shown in Figure 17, the capacitor elements 31 are encapsulated or enclosed in the capacitor housing 32. Each capacitor element 31 is a film capacitor formed by winding metallized foils. The capacitor elements 31 are arranged in such a position that the axial direction of each winding of the metallized foils is oriented in the same direction (Z-direction).

[0063] As it is in Fig. As shown in Figure 17, each capacitor element 31 has an oval shape when viewed in the Z direction. A pair of electrode surfaces 311 are formed on the end faces of each capacitor element 31 in the Z direction. The electrode surfaces 311 are formed, for example, by thermally spraying metal such as aluminum onto both ends of the capacitor element 31 in the Z direction where the electrode surfaces 311 are to be formed.

[0064] The pair of capacitor busbars 4 are connected to the pair of electrode surfaces 311 of the capacitor elements 31. The exposed part 40 of each capacitor busbar 4 is designed such that it is exposed to or on the outside of the resin surface 331, as shown in Fig. Figures 13 to 15 are shown. As described above, each exposed part 40 comprises the plate-like part 401, the power supply connection section 43, and the connection connection sections 42.

[0065] As it is in Fig. As shown in Figures 13 to 15, each plate-like part 401 has a thickness in the Z-direction and is shaped or designed like a substantially rectangular plate extending in the X-direction. One of the pair of plate-like parts 401 is longer in the X-direction than the other. Hereinafter, one of the pair of plate-like parts 401 that is longer in the X-direction than the other is referred to as a long plate-like part 401a, and the plate-like part 401 that is shorter in the X-direction than the other is referred to as a short plate-like part 401b.

[0066] The long plate-like part 401a projects from the short plate-like part 401b in the direction closest to the connecting sections 42 in the X-direction and in the direction farther from the connecting sections 42 in the X-direction (whereby the side closest to the connecting sections 42 is referred to below as an X2 side and the side farther from the connecting sections 42 is referred to as an X1 side). The ends of the long plate-like part 401a and the short plate-like part 401b on the X2 side in the X-direction are substantially aligned. As shown in Fig. As shown in Figure 15, the pair of plate-like parts 401 are partially opposite each other in the Z direction.

[0067] As it is in Fig. As shown in Figures 13 to 15, each power supply connection section 43 projects from the end of the associated plate-like part 401 on the same side (X2 side) in the X direction, so that it extends away from the resin surface 331 in the Y direction. The pair of power supply connection sections 43 are formed on the same plane. The power supply connection section 43 extending from the short plate-like part 401b is flush with the short plate-like part 401b. The power supply connection section 43 extending from the long plate-like part 401a is angled or bent in a step shape at the connection section with the long plate-like part 401a, such that the section opposite the connection section is flush with the power supply connection section 43 that is connected to the short plate-like part 401b.As described above, since the long plate-like part 401a projects in the X direction towards the X1 side, the power supply connection section 43 extending from the long plate-like part 401a is designed to be located further away on the X1 side than the power supply connection section 43 extending from the short plate-like part 401b.

[0068] As it is in Fig. 13 and Fig. As shown in Figure 14, the connection sections 42 project from the region of each plate-like part 401 on the X2 side, extending away from the resin surface 331 in the Y direction. The connection sections 42 are formed in the region of each plate-like part 401 on the X2 side, extending substantially from the center in the X direction. In the present embodiment, the connection sections 42 are connected to terminals (not shown) of the semiconductor modules that form the switching circuit. As shown in Figure 14, the connection sections 42 are connected to terminals of the semiconductor modules that form the switching circuit. Fig. As shown in Figures 13 to 15, the connecting connection sections 42 and the power supply connection sections 43 are arranged next to each other in the X direction.

[0069] As it is in Fig. As shown in Figures 13 to 15, the connection sections 42 comprise module connection sections 421, which are formed at equal intervals in the X-direction. The module connection sections 421 are to be connected to the terminals of the semiconductor modules. The module connection sections 421 are plates with a thickness in the X-direction and are connected to the terminals of the semiconductor modules in the X-direction. The module connection sections 421 are formed on each plate-like part 401 up to the end on the X2 side. The connection sections 42 extending from the long plate-like part 401a and the connection sections 42 extending from the short plate-like part 401b are, viewed in the Z-direction, arranged next to each other in the Y-direction, but are located at different positions in the Z-direction.

[0070] Each plate-like part 401 comprises the specific part or sub-area 404. As shown in the schematic representation of Fig. As shown in Figure 16, the specific part 404 is a through-hole formed by the plate-like part 401 in the thickness direction (namely the Z-direction). As shown in Fig. 13 and Fig. As shown in Figure 14, the specific parts 404 are elongated or elongated in the direction in which the power supply connection sections 43 and the connection connection sections 42 are arranged (namely, the X-direction). In the present embodiment, the specific parts 404 have an oval shape that extends in the X-direction. The length of the specific parts 404 in the X-direction is greater than the length of the power supply connection sections 43 in the X-direction.

[0071] Each specific part 404 extends just to or to the edge of the associated plate-like part 401 on the X1 side. That is, a portion of the plate-like part 401 exists on the X1 side of the specific part 404 of the plate-like part 401. The size of the portion of the plate-like part 401 that exists on the X1 side of the specific part 404 of the plate-like part 401 in the X direction is half or less than half the length of the power supply connection section 43 in the X direction.

[0072] As it is in Fig. 13 and Fig. As shown in Figure 14, each specific part 404 is formed in the region that is closer to the power supply connection section 43 than to the branch connection sections 42. This means that the shortest distance across the plate-like section 401 from the specific part 404 to the power supply connection section 43 is shorter than that from the specific part 404 to the branch connection sections 42.

[0073] At least a part or piece of the specific part 404 is formed in the region where the power supply connection section 43 is opposite the encapsulation resin 33. That is, at least a part or piece of the specific part 404 is located in the region or area between the power supply connection section 43 and the resin surface 331 in the Y-direction, where the power supply connection section 43 and the resin surface 331 of the encapsulation resin 33 are opposite each other. The specific part 404 is formed essentially in the middle of the plate-like part 401 in the Y-direction.

[0074] As it is in Fig. As shown in Figures 13 to 15, the insulating layer 46 is located between the pair of plate-like parts 401 to insulate the plate-like parts 401 from each other. The insulating layer 46 is shaped like a sheet. As shown in Fig. As shown in Figure 13, the insulating layer 46, viewed in the Z direction, is larger than the short plate-like part 401b. The short plate-like part 401b is positioned such that it is located within the insulating layer 46.

[0075] As it is in Fig. 13 and Fig. As shown in Figure 16, the insulating layer 46 includes a positioning element 463 that projects in the Z-direction towards the short, plate-like part 401b. The positioning element 463 is inserted into the specific part 404 (through hole) of the short, plate-like part 401b. The external shape and size of the positioning element 463, viewed in the Z-direction, are essentially the same as the external shape and size of the specific part 404, viewed in the Z-direction. This determines the position of the insulating layer 46 with respect to the short, plate-like part 401b.

[0076] Next, the operational advantages of the present embodiment will be described.

[0077] In the capacitor module 3 of the present embodiment, the exposed part 40 of each capacitor busbar 4, which is exposed with respect to the encapsulation resin 33, comprises the power supply connection section 43 and the connection sections 42. Thus, the DC component of the DC current flowing into the capacitor busbar 4 via the power supply connection section 43 passes over the plate-like part 401 and flows out of the connection sections 42. This prevents the DC component of the DC current from flowing over the capacitor busbar 4 located within the encapsulation resin 33.

[0078] Each plate-like part 401 includes the specific part 404, which has a thickness smaller than that of the surrounding area or section. Thus, the plate-like part 401 has increased electrical resistivity at and around the specific part 404. The specific part 404 is formed in the region of each plate-like part 401 that is closer to the power supply connection section 43 than to the terminal connection sections 42. Therefore, the electrical resistivity of the region of each plate-like part 401 that is closer to the power supply connection section 43 than to the terminal connection sections 42 is increased. Thus, the DC component of the DC current that flowed into the power supply connection section 43 is easily directed towards the terminal connection sections 42.This simply prevents the DC component of the DC current that has flowed into the plate-like part 401 via the power supply connection section 43 from flowing towards the capacitor busbar 4 in the encapsulation resin 33.

[0079] Each specific part 404 is a through-hole extending through the associated plate-like part 401 in the thickness direction. This simply increases the electrical resistivity of the specific part 404 and the surrounding area or section. Furthermore, this prevents the DC component of the DC current flowing in via the power supply connection section 43 from passing through and around the specific part 404 of the plate-like part 401. This also prevents the DC component of the DC current flowing in via the power supply connection section 43 from flowing into the capacitor busbar 4 within the encapsulation resin 33 via the plate-like part 401. Since the specific part 401 is simply designed, the productivity of the capacitor module 3 is also simply improved.

[0080] The insulation layer 46 includes the positioning element 463, which is inserted into the specific element 404. Thus, the specific element 404 can be used to determine the position of the insulation layer 46. This eliminates the need for an additional mechanism to determine the position of the insulation layer 46 and reduces the number of components.

[0081] At least a portion of the specific part or sub-area 404 is formed in the region where the power supply connection section 43 and the encapsulation resin 33 are located opposite each other. This increases the electrical resistivity of the region of the plate-like part 401, which represents the shortest path between the power supply connection section 43 and the capacitor busbar 4 in the encapsulation resin 33. This further prevents the DC component of the DC current that has flowed into the power supply connection section 43 from flowing into the capacitor busbar 4 in the encapsulation resin 33 via the plate-like part 401.

[0082] The specific part 404 is formed in the region that is closer to the power supply connection section 43 than to the connection sections 42. This increases the electrical resistivity of the region of the plate-like part 401 that is closer to the power supply connection section 43. Thus, the DC component of the DC current that has flowed into the power supply connection section 43 is more easily guided towards the connection sections 42. Consequently, it is more easily prevented that the DC component of the DC current that has flowed into the plate-like part 401 via the power supply connection section 43 flows towards the capacitor busbar 4 in the encapsulation resin 33.

[0083] As described above, the present embodiment provides a capacitor that simply prevents the capacitor elements and the encapsulation resin from absorbing heat. Third example

[0084] The present embodiment is a modification of the second embodiment in which the structure of the specific part 404 is modified, as shown in Fig. 18 is shown.

[0085] In the present embodiment, each plate-like part 401 comprises several specific parts or sub-areas 404. In the present embodiment, each plate-like part 401 comprises two specific parts 404. The two specific parts 404 have an oval shape extending in the X-direction and are located next to each other in the X-direction. In the plate-like part 401, one of the specific parts 404 is located in a region where the power supply connection section 43 and the encapsulation resin (see reference numeral 33 in Figure 401) are located. Fig. 15) are opposite each other. The other of the specific parts 404 is located at a position adjacent to the aforementioned specific part 404 on the X2 side. A part or segment of the capacitor busbar 4 exists on both sides of each specific part 404 in the X direction in each plate-like part 401.

[0086] Everything else is the same as in the second example.

[0087] The reference numerals used in the third embodiment and the following embodiments, which are the same as those in the embodiments already discussed, represent equivalent components to those in the embodiments already discussed, unless otherwise specified.

[0088] In the present embodiment, each plate-like part 401 comprises the several specific parts 404. Thus, compared to a case in which each plate-like part 401 comprises one large specific part 404, the strength or stability of each plate-like part 401 is increased, which improves the natural frequency of each plate-like part 401. This improves the strength or resistance of each plate-like part 401 to vibration.

[0089] Furthermore, the same operational advantages are achieved as those of the second embodiment. Fourth embodiment

[0090] As it is in Fig. As shown in Figure 19, the present embodiment is also a modification of the second embodiment, in which the structure of the specific part 404 is modified.

[0091] In the present embodiment, the specific part 404 has a rectangular shape that is slightly longer in the X direction.

[0092] Everything else is the same as in the second example.

[0093] The present embodiment also achieves the same operational advantages as the second embodiment. Fifth embodiment

[0094] As it is in Fig. As shown in Figure 20, the present embodiment is a modification of the second embodiment in which the structure of the specific part 404 is modified.

[0095] The specific part 404 is connected to the edge of the plate-like part 401 that is furthest from the connecting sections 42 (X1 side). This means that the specific part 404 is open on the X1 side. The specific part 404 is a long slot extending in the X direction.

[0096] Everything else is the same as in the second example.

[0097] In the present embodiment, the DC component of the DC current introduced into the plate-like part 401 via the power supply connection section 43 is simply prevented from flowing through the X1 side of the specific part 404 of the plate-like part 401 towards the capacitor busbar 4 in the encapsulation resin 33. Thus, the DC component of the DC current introduced into the plate-like part 401 via the power supply connection section 43 is more easily guided towards the connection sections 42.

[0098] Furthermore, the same operational advantages are achieved as those of the second embodiment.

[0099] Although the present disclosure has been described according to the embodiments, it is obvious that the present disclosure is not limited to these embodiments and configurations. The present disclosure includes various modifications and transformations / designs that fall within the scope of equivalence. Furthermore, various combinations and configurations, or further combinations and configurations that include only one or more additional elements or fewer than all the elements, are included to the extent and in the basic concept that can be obtained from the present disclosure. For example, as described in Fig.As shown in Figure 21, the specific part can be a recess or indentation instead of a through-hole. In this case, the position of the insulating layer 46 with respect to the capacitor busbar 4 can be determined by inserting the position-determining section 463 of the insulating layer 46 into the recess or indentation of the capacitor busbar 4 according to the second embodiment.

Claims

[1] Power converter (1) with: a switching circuit (20); a capacitor module (3) which is electrically connected to the switching circuit; an auxiliary capacitor module (5) connected in parallel to the capacitor module; and a device housing (12) which contains the switching circuit, the capacitor module and the auxiliary capacitor module, wherein The capacitor module includes: a capacitor element (31), a capacitor housing (32) that contains the capacitor element, an encapsulation resin (33) that encapsulates the capacitor element in the capacitor housing, and a capacitor busbar (4) which connects the capacitor element to a power terminal of the switching circuit, wherein the capacitor busbar includes: an element connection section (41) that is connected to the capacitor element within the encapsulation resin, a connecting section (42) which is connected to the power connection outside the encapsulation resin, and a power supply connection section (43) which is connected to a power supply wiring (54) outside the encapsulation resin, wherein the power supply wiring is electrically connected to a DC power supply, wherein the capacitor busbar includes a DC path (44) which represents a current path between the terminal connection section and the power supply connection section, and the DC path is exposed to the outside of the encapsulation resin, the auxiliary capacitor module is connected to the power supply connection section of the capacitor busbar, the auxiliary capacitor module is detachably attached to the power supply connection section by means of a fastening element (11), and a fastening direction of a fastening element (135) that secures the auxiliary capacitor module and a fastening direction of the fixing element are the same. [2] Power converter according to claim 1, wherein the capacitor busbar of the capacitor module comprises a positive electrode busbar (4P) and a negative electrode busbar (4N) which are connected to opposite electrodes of the capacitor element, the positive electrode busbar and the negative electrode busbar each comprising an opposing section (45) on a part of their respective DC paths, the opposing sections being opposite each other in a thickness direction, with an insulating layer (46) between them, and, viewed in the thickness direction, the power supply connection sections projecting from the opposing sections and the insulating layer. [3] Power converter according to claim 2, wherein each facing section comprises a flat main facing section (451) and an upright facing section (452) extending from the main facing section in a thickness direction of the main facing section, the insulation layer comprising a main insulation section (461) located between the pair of main facing sections and an upright insulation section (462) located between the pair of upright facing sections, and the power supply connection section is angled relative to the upright facing section in a thickness direction of the upright facing section and is configured to be parallel to the main facing section. [4] Power converter (1) with: a switching circuit (20); and a capacitor module (3) which is electrically connected to the switching circuit, wherein The capacitor module includes: a capacitor element (31), a capacitor housing (32) that contains the capacitor element, an encapsulation resin (33) that encapsulates the capacitor element in the capacitor housing, and a capacitor busbar (4) which connects the capacitor element to a power terminal of the switching circuit, wherein the capacitor busbar includes: an element connection section (41) that is connected to the capacitor element within the encapsulation resin, a connecting section (42) which is connected to the power connection outside the encapsulation resin, and a power supply connection section (43) which is connected to a power supply wiring (54) outside the encapsulation resin, wherein the power supply wiring is electrically connected to a DC power supply, wherein the capacitor busbar includes a DC path (44) which represents a current path between the terminal connection section and the power supply connection section, and the DC path is exposed to the outside of the encapsulation resin, the capacitor busbar of the capacitor module comprises a positive electrode busbar (4P) and a negative electrode busbar (4N) which are connected to opposite electrodes of the capacitor element, the positive electrode busbar and the negative electrode busbar each comprising an opposing section (45) on a portion of their respective DC paths, the opposing sections being opposite each other in a thickness direction with an insulating layer (46) between them, and, viewed in the thickness direction, the power supply connection sections projecting from the opposing sections and the insulating layer, and Each facing section comprises a flat main facing section (451) and an upright facing section (452) extending from the main facing section in a thickness direction of the main facing section, the insulation layer comprises a main insulation section (461) located between the pair of main facing sections and an upright insulation section (462) located between the pair of upright facing sections, and the power supply connection section is angled relative to the upright facing section in a thickness direction of the upright facing section and is designed to be parallel to the main facing section. [5] Power converter according to claim 4, additionally with an auxiliary capacitor module (5) which is connected in parallel to the capacitor module, wherein the auxiliary capacitor module is connected to the power supply connection section of the capacitor busbar. [6] Power converter according to claim 5, wherein the auxiliary capacitor module is detachably attached to the power supply connection section by means of a fastening element (11).

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