Electronic assembly

Abstract

Electronic assembly (100), comprising - a capacitor unit (10) with at least two capacitor elements (14) on a support element (13) formed by a printed circuit board with a first capacitor terminal (11) and a second capacitor terminal (12). - a semiconductor unit (20) with a first semiconductor terminal (21) and a second semiconductor terminal (22), and - a busbar (30) with a first busbar element (31) and a second busbar element (32), wherein - the first capacitor terminal, the first semiconductor terminal and the first busbar element are directly connected to each other and the second capacitor terminal, the second semiconductor terminal and the second busbar element are directly connected to each other, so that the capacitor unit, the semiconductor unit and the busbar are directly connected to each other.

Description

[0001] The following describes an electronic assembly. The electronic assembly can, in particular, comprise a capacitor unit, preferably a capacitor unit forming a DC link capacitor.

[0002] Capacitors, such as metal film capacitors, are frequently used as DC link capacitors and are an essential component in power electronics, for example, in inverter applications. Examples include applications in renewable energy, automotive applications such as power converters in electric vehicles, and railway applications such as drive converters. The development of suitable DC link capacitors is closely linked to the development of the semiconductor devices that contain the inverter switching electronics used in power electronics. The current trend in power electronics is toward increasingly compact inverters capable of operating at higher switching frequencies, temperatures, and power densities. These goals can lead to requirements such as higher capacitor operating temperatures, higher current densities, and higher harmonic frequencies.Furthermore, the space requirements of inverters are constantly decreasing and can vary depending on the often non-standardized specifications. To meet these requirements, it may therefore be desirable to achieve sufficient DC link capacitor performance at high frequencies.

[0003] This can relate in particular to the electrical series resistance (ESR) of the capacitor, but also to the loop inductance of the inverter. Reducing the ESR also reduces losses. The loop inductance can depend, among other things, on the electrical series inductance (ESL) of the capacitor, the inductance of the semiconductor device, the inductance of the electrical connections, and so on. Furthermore, it may be desirable to reduce the size of the overall DC link solution, improve the thermal performance of the capacitors used in the applications mentioned above, and provide modular designs so that the DC link solution can be easily adapted to the specific requirements of the inverters, thereby shortening the development phase.

[0004] At least one objective of certain embodiments is the provision of an electronic assembly, preferably an electronic assembly with a capacitor unit.

[0005] This purpose is achieved by the subject matter according to the independent claim. Advantageous embodiments and further developments of the subject matter are characterized in the dependent claims and are also disclosed by the following description and the drawings.

[0006] According to at least one embodiment, an electronic assembly is specified. In particular, the electronic assembly can comprise at least one capacitor unit. Furthermore, the electronic assembly can comprise at least one semiconductor unit. In addition, the electronic assembly can comprise a busbar.

[0007] According to another embodiment, the capacitor unit comprises a support element that carries at least one capacitor element. Particularly preferably, the capacitor unit comprises at least two capacitor elements. Preferably, all capacitor elements of the capacitor unit are similar to one another.

[0008] According to a further embodiment, the support element is formed by a printed circuit board (PCB). The support element can have capacitor terminals, i.e., electrical connections for the mechanical and electrical connection of the support element, and thus the capacitor unit, to other components, particularly preferably to other components of the electronic assembly such as the semiconductor unit and the busbar. The support element can, for example, have two or three capacitor terminals, depending on the configuration of the electronic assembly. Particularly preferably, the support element, and thus the capacitor unit, comprises a first capacitor terminal and a second capacitor terminal. The first and second capacitor terminals can preferably be configured to provide electrical connections with different polarities.

[0009] In particular, the electronic assembly may comprise one or more capacitor units. If the electronic assembly comprises more than one capacitor unit, the capacitor units are preferably independent components; that is, each capacitor unit comprises a single support element with a first capacitor terminal and a second capacitor terminal and preferably has at least two capacitor elements mounted on the support element. The features and embodiments of a capacitor unit and its components described above and below may preferably apply to all capacitor units of the electronic assembly.

[0010] According to a further embodiment, the semiconductor unit comprises switching electronics for inverter functionality; that is, the semiconductor unit can be configured to convert a direct current (DC) electrical signal into an alternating current (AC) electrical signal. Consequently, the semiconductor unit can have a DC side and an AC side, with the DC side being an input and the AC side an output. Particularly preferably, the electronic assembly can be at least part of an inverter device or an inverter device itself. Furthermore, the capacitor unit can be at least part of an intermediate circuit capacitor or an intermediate circuit capacitor.The electronic assembly can be, for example, an inverter in the form of a two-level inverter, a three-level inverter, a cascade inverter, a modular multi-level inverter, or an inverter with dual positive / negative terminals. In the latter case, the capacitor unit's support element preferably has three capacitor terminals. The inverter can be a single-phase inverter or a multi-phase inverter, e.g., a three-phase inverter. For each phase, the electronic assembly can comprise at least one capacitor unit and one semiconductor unit. Consequently, the features and embodiments described in connection with a semiconductor unit can apply to all semiconductor units of the electronic assembly. In particular, all semiconductor units of the electronic assembly can be configured similarly.

[0011] According to a further embodiment, the semiconductor unit comprises semiconductor terminals, i.e., electrical terminals for mechanically and electrically connecting the capacitor unit to other components, e.g., components of the electronic assembly such as the at least one capacitor unit and the busbar. The semiconductor unit may, for example, comprise at least two semiconductor terminals. In particular, the semiconductor unit may have a first semiconductor terminal and a second semiconductor terminal. The first and second semiconductor terminals may be terminals on a DC side of the semiconductor unit and may be configured to be connected to opposite electrical polarities of a DC electrical signal. Furthermore, the semiconductor unit may have at least a third semiconductor terminal on an AC side.

[0012] According to a further embodiment, the busbar comprises a first busbar element and a second busbar element. In particular, the busbar can be configured as a DC busbar, i.e., a busbar electrically connected to the DC side of the semiconductor unit. Consequently, the first busbar element and the second busbar element can preferably be configured to be connected to different electrical polarities of a DC electrical signal. Each of the first and second busbar elements can, for example, be or comprise one or more metal sheets or plates, wherein the first busbar element and the second busbar element are electrically isolated from each other.

[0013] According to another embodiment, the capacitor unit, the semiconductor unit, and the busbar are directly connected to each other. This can particularly mean that the first capacitor terminal, the first semiconductor terminal, and the first busbar element are directly connected to each other, and that the second capacitor terminal, the second semiconductor terminal, and the second busbar element are directly connected to each other.That a capacitor terminal, a semiconductor terminal and a busbar element are “directly connected” may preferably mean that a first element selected from the capacitor terminal, the semiconductor terminal and the busbar element is in direct mechanical contact with the other two elements, such that the first element is preferably arranged between the other two elements, thereby forming a sandwich-like structure in which the first element is embedded between the other two elements.The contact area of ​​the sandwich-like first element with one of the other two elements and the contact area of ​​the sandwich-like first element with the other of the other two elements preferably overlap when considering the stacking direction of the three elements, such that preferably the same part of the first element has direct mechanical contact with one of the other two elements. The direct connection can comprise one or more screw connections, a soldered connection, or a welded connection. In other words, the directly connected capacitor terminal, the semiconductor terminal, and the busbar element can be screwed, soldered, or welded together.Preferably, the first busbar element is arranged between the first capacitor terminal and the first semiconductor terminal, and the second busbar element is arranged between the second capacitor terminal and the second semiconductor terminal. However, it is also possible for the first capacitor terminal to be arranged between the first busbar element and the first semiconductor terminal, and for the second capacitor terminal to be arranged between the second busbar element and the second semiconductor terminal. Furthermore, it is also possible for the first semiconductor terminal to be arranged between the first busbar element and the first capacitor terminal, and for the second semiconductor terminal to be arranged between the second busbar element and the second capacitor terminal.

[0014] According to a further embodiment, the electronic assembly comprises two capacitor units, wherein the two capacitor units, the semiconductor unit, and the busbar are directly connected to one another. In particular, each capacitor unit can have a first capacitor terminal and a second capacitor terminal. The first semiconductor terminal can preferably be arranged between the first capacitor terminals of the two capacitor units, and the second semiconductor terminal can preferably be arranged between the second capacitor terminals of the two capacitor units. The first busbar element can be in direct mechanical contact with the first capacitor terminal of one or both of the two capacitor units, and the second busbar element can be in direct mechanical contact with the second capacitor terminal of one or both of the two capacitor units.Accordingly, the first capacitor terminals of the two capacitor units, the first semiconductor terminal, and the first bus element can be directly connected to each other, and the second capacitor terminals of the two capacitor units, the second semiconductor terminal, and the second bus element can be directly connected to each other. It is particularly preferred that the semiconductor unit is directly connected to exactly one capacitor unit or to exactly two capacitor units.

[0015] As described above, the electronic assembly can comprise a plurality of capacitor units and a plurality of semiconductor units. Each semiconductor unit, together with at least one capacitor unit, particularly preferably with one or two capacitor units, forms at least part of a phase of a multiphase inverter device. Thus, for each of the capacitor units and semiconductor units, and therefore for each of the phases, at least one capacitor unit, one semiconductor unit, and the busbar are directly connected to each other.

[0016] According to a further embodiment, each of the at least two capacitor elements is a metallized film capacitor element. That is, each capacitor element can consist, for example, of two metallized dielectric films, i.e., plastic films with a metallization, for example with or made of aluminum and / or zinc, as electrode layers, wherein the two metallized dielectric films are wound together into a coil, for example a cylindrical coil, which can then be compressed into an elliptical or oval coil. The two metallized films forming a coil can be wound slightly offset from each other, so that each of the electrode layers protrudes laterally on two opposite sides of the coil. The protruding electrode layers can be coated, for example, with a liquefied contact metal, e.g. with or made of tin, zinc, and / or aluminum, which, for example,The metallization process is sprayed onto both lateral ends of the winding. This metallization process is also known as schopage. Consequently, each of the at least two capacitor elements has a first contact surface and a second contact surface facing away from the first. However, other manufacturing processes and thus other embodiments of capacitor elements are also possible. To adapt the properties of the capacitor elements to the requirements of the electronic assembly, the dimensions of the capacitor elements can be adjusted, for example, by changing the number of turns and the winding pressure, which affects the length and height of the capacitor elements, and by changing the width of the metallized dielectric films, which affects the width of the capacitor elements, i.e., the distance between the first and second contact surfaces.

[0017] Furthermore, all capacitor elements of the capacitor unit can be electrically connected to one another, preferably in series or parallel. Thus, all capacitor elements of the capacitor unit together can form a single functional unit, i.e., a single capacitor. Particularly preferably, the first contact surfaces of all capacitor elements of the capacitor unit are electrically connected to the first capacitor terminal, and the second contact surfaces of all capacitor elements of the capacitor unit are electrically connected to the second capacitor terminal. Particularly preferably, the at least two capacitor elements can be arranged on the support element such that the first contact surface of at least one of the at least two capacitor elements of the capacitor unit faces the second contact surface of a directly adjacent of the at least two capacitor elements.Furthermore, the capacitor unit can comprise more than two capacitor elements arranged in a row, such that for each pair of directly adjacent capacitor elements, the first contact surface of one of the directly adjacent capacitor elements faces the second contact surface of the other of the directly adjacent capacitor elements. In other words, at least one capacitor element can be located on the support element between two other directly adjacent capacitor elements. For each of the capacitor elements located between two other directly adjacent capacitor elements, the first contact surface can face the second contact surface of one of the two directly adjacent capacitor elements, and the second contact surface can face the first contact surface of the other of the two directly adjacent capacitor elements.Consequently, the polarities of the contact surfaces of the at least two capacitor elements can alternate, so that the contact surfaces of two directly adjacent capacitor elements facing each other can overlap in the arrangement direction of the capacitor elements and exhibit different polarities. This arrangement can reduce the ESR and ESL of the capacitor unit.

[0018] Furthermore, the properties of a capacitor unit can be adapted by adding any number of capacitor elements ( ) and / or by changing the dimensions of the capacitor elements as described above, in order to meet power density and energy requirements, particularly within the application limits of film capacitors. Additionally, the connectivity of the capacitor terminals to the semiconductor terminals can be easily adapted with minor modifications. Due to the modularity of the electronic assembly, the designs of the one or more capacitor units, the one or more semiconductor units, and the busbar can thus be easily adapted to the electrical and / or mechanical constraints and requirements.

[0019] According to a further embodiment, the support element comprises at least one first conductor track electrically connected to the first capacitor terminal and at least one second conductor track electrically connected to the second capacitor terminal. For example, the first capacitor terminal can be part of the at least one first conductor track, and the second capacitor terminal can be part of the at least one second conductor track. Furthermore, the at least one first conductor track and the at least one second conductor track can overlap at least partially. In particular, the conductor tracks can overlap at least partially in a direction perpendicular to a principal extension plane of the support element. The stacking direction of the conductor tracks is perpendicular to the principal extension plane of the support element. The conductor tracks are sheet-shaped with a principal extension plane parallel to the principal extension plane of the support element.Furthermore, the carrier element can have a plurality of first conductor tracks and a plurality of second conductor tracks, which are arranged alternately one above the other and all overlap. Particularly preferably, the conductor tracks of the carrier element can be metal layers of the printed circuit board, which can be arranged on one or both main surfaces or inside the carrier element.

[0020] According to a further embodiment, a portion of the busbar overlaps with a portion of the at least one first conductor track and / or the first capacitor terminal and with a portion of the at least one second conductor track and / or the second capacitor terminal. Consequently, at least one of the first and second busbar elements can have an overlapping portion that overlaps with at least a portion of the at least one first conductor track and / or the first capacitor terminal and with at least a portion of the at least one second conductor track and / or the second capacitor terminal.

[0021] According to another embodiment, the at least two capacitor elements are housed in a common casing on the support element. Particularly preferably, all capacitor elements of the capacitor unit are housed in a common casing on the support element. Preferably, the casing can comprise a resin-filled housing, with all capacitor elements arranged within the casing and enclosed by the resin.

[0022] According to a further embodiment, the busbar comprises a thermal component designed for heat dissipation to the environment and / or a cooling unit. Particularly preferably, the thermal component is in thermal contact with a cooling unit of the semiconductor unit. For example, one of the first and second busbar elements can comprise a thermal component that is in thermal contact with a cooling unit of the semiconductor unit and / or is designed for heat dissipation to the ambient air. Consequently, the heat generated in the at least one capacitor unit of the electronic assembly can be dissipated from the at least one capacitor unit via the thermal component.

[0023] The electronic assembly described here is based on a modular approach with at least one capacitor unit directly connected to a semiconductor unit and a decoupled busbar, preferably for DC link solutions in inverter applications. In particular, the capacitor element preferably consists of a printed circuit board with overlapping conductor tracks as a carrier element and at least two capacitor elements mounted with alternating polarity of the contact pads as described above. The polarity reversal and the overlapping conductor tracks reduce ESL and ESR. Using a printed circuit board as a carrier element facilitates adapting the dimensions to the inverter's space requirements. The direct connection of the at least one capacitor unit to the at least one semiconductor unit contributes to reducing the footprint.By decoupling the busbar from the circuit board of the at least one capacitor unit and by employing busbar cooling techniques, improved thermal performance, e.g., of the at least one capacitor unit, can be achieved. Furthermore, a redesign process is simple and can be adapted to mechanical or electrical requirements with minimal modifications, allowing the at least one capacitor unit to be easily tailored to the specific requirements of the electronic assembly.

[0024] Consequently, the electronic assembly described here preferably comprises metallized film capacitor elements on a printed circuit board, forming a DC link capacitor suitable for high-frequency applications. Furthermore, a common DC connection with low inductance and balanced inductance can be provided between several semiconductor units, wherein the at least one capacitor unit can form a modular DC link capacitor with a reduced footprint. In particular, the electronic assembly can homogenize the impedance between several semiconductor units and reduce the inductance between them. Additionally, the loop inductance can be reduced.

[0025] Furthermore, the thermal behavior of the electronic assembly can be improved. In particular, the aforementioned improved high-frequency performance can lead to a reduction in high-frequency ohmic losses, i.e., the total series resistance (ESR) of at least one capacitor unit decreases, as do the overall losses. Additionally, the DC side, i.e., the input side in an inverter application, is decoupled into two sections: one for the capacitor units, which form the intermediate circuit capacitors with direct connection to the semiconductor units, and another section formed by the DC power rail. The power rail serves as a connection between the semiconductor terminals. This results in a lower temperature for the capacitor units, which improves heat dissipation via the capacitor terminals and increases the inverter's efficiency.

[0026] Further advantages, advantageous embodiments and further developments result from the embodiments described below in connection with the figures. Fig. shows a schematic representation of an electronic assembly according to one embodiment, The Fig. Figures 2A to 2F show different representations of a capacitor unit of an electronic assembly according to a further embodiment. The Fig. show various schematic representations of a capacitor unit of an electronic assembly according to a further embodiment, Fig. Figure 4 shows a schematic representation of part of a capacitor unit of an electronic assembly according to a further embodiment, Fig. shows a schematic representation of a capacitor unit of an electronic assembly according to a further embodiment, The Fig. Figures 6A to 6E show various schematic representations of a part of an electronic assembly according to a further embodiment. Fig. Figure 7 shows a schematic representation of part of an electronic assembly according to a further embodiment, The Fig. show various schematic representations of an electronic assembly according to a further embodiment, Fig. shows a schematic representation of an electronic assembly according to a further embodiment, The Fig. show schematic representations of an electronic assembly according to a further embodiment, Fig. shows a schematic representation of an electronic assembly according to a further embodiment.

[0027] In the embodiments and illustrations, identical, similar, or seemingly identical elements are each designated with the same reference numerals. The depicted elements and their relative sizes are not to be considered true to scale; rather, individual elements, such as layers, components, building elements, and areas, may have been exaggerated to better illustrate and / or understand the concept.

[0028] The figures described below refer to exemplary embodiments. However, the following description is not to be understood as a limitation of the disclosure. Therefore, features of the following embodiments that are not listed in an independent claim are to be understood as optional and can be provided as required. In particular, the features and embodiments described in connection with the figures can also be combined with one another according to further embodiments, even if not all such combinations are expressly described. Furthermore, the embodiments described in connection with the figures may alternatively or additionally have further features as described in the general part.

[0029] Fig. Figure 1 shows a schematic representation of an electronic assembly 100. The electronic assembly 100 is, for example, a three-phase inverter. The electronic assembly 100 can be configured, for example, to convert direct current power supplied by a direct current source 90 into alternating current power to operate an alternating current load 91, e.g., a three-phase electric motor. The direct current source 90 and the alternating current load 91 are in Fig. The electronic assembly 100 comprises three phases, each phase comprising at least one capacitor unit 10 and one semiconductor unit 20. In particular, each capacitor unit 10 comprises a first capacitor terminal 11 connected to a first semiconductor terminal 21 of a corresponding semiconductor unit 20, and a second capacitor terminal 12 connected to a second semiconductor terminal 22 of the corresponding semiconductor unit 20. On the DC side, the phases of the electronic assembly 100 are interconnected by a busbar 30 comprising a first busbar element 31 and a second busbar element 32.In particular, for each phase, a first capacitor terminal 11, a first semiconductor terminal 21, and the first busbar element 31 are directly connected to each other, and a second capacitor terminal 12, a second semiconductor terminal 22, and the second busbar element 32 are directly connected to each other, as described in more detail in connection with the following figures. On the AC side, each of the semiconductor units 20 has a third semiconductor terminal 23, which is connected to the AC load 91.

[0030] Although in Fig. The fact that a three-phase inverter is shown in Figure 1 should not be interpreted as a limitation of the electronic assembly 100. On the contrary, the electronic assembly 100 can be implemented as any other device with at least one capacitor unit 10, at least one semiconductor unit 20, and a busbar 30. Several preferred embodiments and features of the electronic assembly 100 and of components of the electronic assembly 100 are explained in detail in connection with the following figures. When the description of one or more figures refers to elements or components not shown in that figure(s), these references are to other figures in which those elements or components are shown.

[0031] The Fig. Figures 2A to 2F show different views of a capacitor unit 10, as used in the Fig. The electronic assembly 100 shown in section 1 can be used. Fig. 2A and Fig. Figure 2B shows the capacitor unit 10 in a top view and a front view, while the Fig. Figure 2C shows the capacitor unit 10 in a three-dimensional view. Fig. 2D shows parts of capacitor unit 10 in a transparent top view, while Fig. 2E parts of the capacitor unit 10 shown in a top view. Fig. Figure 2F shows a three-dimensional view of parts of capacitor unit 10 in a bottom view. The following description applies equally to all Fig. 2A to 2F.

[0032] The capacitor unit 10 comprises a support element 13 which carries at least one capacitor element 14. Particularly preferably, the capacitor unit 10 has at least two capacitor elements 14. In the illustrated embodiment, the capacitor unit 10 has three capacitor elements 14, which are attached to a top surface of the support element 13. Preferably, all capacitor elements 14 of the capacitor unit 10 are similar to each other.

[0033] The support element 13 is preferably formed by a printed circuit board (PCB) having at least one electrically insulating layer, e.g. made of a plastic material, and two conductive traces 15, 16. Furthermore, the support element 13 comprises the first and second capacitor terminals 11, 12 for mechanically and electrically connecting the support element 13, and thus the capacitor unit 10 as a whole, to other components, particularly preferably a semiconductor unit 20 and the busbar 30, as described in connection with Fig. 1 described. In the illustrated embodiment, the support element 13 has two capacitor terminals, namely the first and second capacitor terminals 11, 12. However, the capacitor unit 10 can also have, for example, three capacitor terminals, depending on the configuration of the electronic assembly 100 and, in particular, the semiconductor unit 10. The first and second capacitor terminals 11, 12 are configured to provide electrical connections with different polarities.

[0034] Each of the capacitor elements 14 is a metallized film capacitor element, for example as described above in the general section. In particular, each of the capacitor elements 14 has a first contact surface 141 and a second contact surface 142, which faces away from the first contact surface 141 and can be formed, for example, by the blade method described above in the general section.

[0035] Furthermore, the support element 13 comprises at least one first conductor track 15, which is electrically connected to the first capacitor terminal 11, and at least one second conductor track 16, which is electrically connected to the second capacitor terminal 12. In the embodiment shown, the support element 13 has a first conductor track 15 on a main surface of the support element 13, which is a top surface of the support element 13, and a second conductor track 16 on another main surface of the support element 13, which is a bottom surface of the support element 13. Preferably, as shown, for example, in the Fig. As shown in Figures 2D to 2F, the first capacitor terminal 11 is part of at least one first conductor track 15, and the second capacitor terminal 12 is part of at least one second conductor track 16. Furthermore, the first capacitor terminal 11 includes a socket- or pin-shaped first contact part 110, and the second capacitor terminal 12 includes a socket-shaped second contact part 120, so that the first and second capacitor terminals 11, 12 can be mechanically and electrically connected via a screw, solder, or weld connection using the contact parts 110, 120. However, other configurations of the capacitor terminals 11, 12 are also possible.

[0036] Furthermore, the first conductor track 15 and the second conductor track 16 overlap, as e.g. in the Fig. 2D and Fig. 2E can be seen. In particular, the conductor tracks 15, 16 overlap in a direction perpendicular to a principal extension plane of the support element 13, i.e., in the view of the top or bottom of the support element 13. Consequently, the stacking direction of the conductor tracks 15, 16 is perpendicular to the principal extension plane of the support element 13. The conductor tracks 15, 16 are planar with a principal extension plane parallel to the principal extension plane of the support element 13 and can be metal layers, e.g., copper layers, of the printed circuit board, which can also be arranged on a main surface and / or within the support element 13.

[0037] The capacitor elements 14 are connected to the conductor tracks 15, 16 via contact pins 17, which can be soldered to the contact surfaces 141, 142, so that all capacitor elements 14 are electrically connected to each other, for example in series or, as in the illustrated embodiment, in parallel. Consequently, all capacitor elements of the capacitor unit together form a single functional unit, i.e., a single capacitor. The first contact surfaces 141 of all capacitor elements 14 are electrically connected to the first capacitor terminal 11 via the first conductor track 15, and the second contact surfaces 142 of all capacitor elements 14 are electrically connected to the second capacitor terminal 12 via the second conductor track 16.

[0038] Furthermore, the capacitor elements 14 are arranged on the support element 13 such that the first contact surface 141 of one capacitor element 14 and the second contact surface 142 of a directly adjacent capacitor element 14 are opposite each other. Since the first and second contact surfaces 141, 142 have different polarities, as shown in Fig. As indicated by the “+” and “-” symbols in Figure 2A, the contact surfaces 141, 142 are arranged alternately, i.e., with alternating polarities, so that directly adjacent contact surfaces 141, 142 of two directly adjacent capacitor elements 14 can overlap in the direction of arrangement of the capacitor elements 14 and have opposite polarities. This arrangement can reduce the ESR and ESL of the capacitor unit.

[0039] The Fig. Figures 3A to 3C show, in a three-dimensional view of the top, a top view, and a three-dimensional view of the bottom, a further embodiment of the capacitor unit 10, which, compared to the previous embodiment, has a housing 18. The housing 18 is a common housing for all capacitor elements 14 of the capacitor unit 10. In other words, the capacitor elements 14 are all arranged in the common housing 18 on the support element 13. The housing can, for example, consist of a plastic housing, the housing being filled with a resin that encapsulates and protects the capacitor elements 14.

[0040] As described in connection with the previous embodiments, the carrier element 13 can have the first conductor track 15 on the top side of the printed circuit board and the second conductor track 16 on the bottom side of the printed circuit board. As in Fig. As indicated, in a further embodiment the carrier element 13 can have a plurality of first conductor tracks 15 and a plurality of second conductor tracks 16, which are arranged alternately one above the other and all overlap each other. In the illustrated embodiment, the first conductor tracks 15 and the second conductor tracks 16 are each connected to one another by the contact parts 110, 120 of the capacitor terminals 11, 12. The conductor tracks 15, 16 of the carrier element 13 are metal layers of the printed circuit board, which are arranged on both main surfaces and inside the carrier element 13. In the illustrated embodiment, two first and two second conductor tracks 15, 16 are shown only as examples. By increasing the number of conductor tracks 15, 16, the current-carrying properties of the carrier element 13 can be increased.

[0041] The ones related to the Fig. 2A to 4 described capacitor unit 10 for the electronic assembly 100 of the Fig. 1 preferably comprises, as previously described, capacitor elements 14 formed by metallized film capacitor elements connected in parallel or in series. All capacitor elements 14 are connected to form a complete capacitor via the printed circuit board of the carrier element 13. The polarity of the successive capacitor elements is alternating, and the contact surfaces 141, 142 of directly adjacent capacitor elements 14 are arranged opposite each other. This ensures that the planes of the contact surfaces 141, 142 with opposite polarities of directly adjacent capacitor elements 14 are parallel and as close together as possible, preferably limited only by the required isolation distance due to the operating voltage of the DC side of the electronic assembly 100.Due to the close proximity of the contact surfaces 141, 142 with opposite polarities, the ESL of each capacitor element 14 can be reduced thanks to the partial flux cancellation, as currents of opposite polarity flow in close proximity. This physical effect can also improve the current distribution of the capacitor elements at high frequencies, thus reducing the ESR of the capacitor elements 14.

[0042] It is possible to adjust and change the properties of the capacitor unit 10 by adding or removing capacitor elements 14 to or from the support element 13 along its longest dimension, i.e. in a row. Fig. Figure 1 shows, for example, an embodiment of the capacitor unit 10 with five capacitor elements 14. Other numbers of capacitor elements 14 are also possible. Furthermore, as described above, it is possible to change each of the three dimensions of the capacitor elements 14, i.e., to change the length, width, and / or height of the capacitor elements 14, by varying the size of the metallized foils and / or the number of turns when winding the metallized foils. Consequently, the design of the capacitor unit 10 is modular and can be adapted to the mechanical requirements, e.g., the required footprint of the inverter, and to the electrical requirements, such as capacitance, power, and / or energy density, of the specific application of the electronic assembly 100, since a change in the height and / or length of the capacitor elements 14 affects their capacitance. If the width of the capacitor elements 14 is changed, i.e.,When the distance between the contact surfaces 141, 142 is changed, the current density capability and the capacitance are affected.

[0043] Since all capacitor elements 14 of the capacitor unit 10 can be housed in a single casing 18, which consists, for example, of a resin-filled casing, as in the Fig. Figures 3A to 3C are shown, and since all capacitor elements 14 are connected in close proximity to each other and to the support element 13 formed from a single printed circuit board with two or three capacitor terminals 11, 12, the final design of the capacitor unit 10 and, in particular, its space requirements can be reduced. This makes the design ideal for applications with limited space, e.g., in power converters.

[0044] Since the carrier element 13 can have a two- or multi-layered arrangement of the conductor tracks 15, 16 with alternating polarity, as e.g. in Fig. As indicated in 4, both the total series resistance and the total series inductance of the capacitor element 10 can also be reduced.

[0045] To complete the DC link of the electronic assembly 100 of Fig. To construct 1, three capacitor units 10, as described in connection with the preceding embodiments, can be directly connected to the power rail 30. Fig. Figures 6A to 6E show, in various three-dimensional views, a top view, and a transparent view of the top surface of several parts, an embodiment of three capacitor units 10 directly connected to a busbar 30. As also shown in connection with Fig. As described in Figure 1, the busbar 30 comprises a first busbar element 31 and a second busbar element 32. In particular, the busbar 30 is designed as a DC busbar and is electrically connected to the DC side of the electronic assembly 100. Fig. 1 connected. Consequently, the first busbar element 31 and the second busbar element 32 are configured to be connected to different electrical polarities of a DC electrical signal. Each of the first and second busbar elements 31, 32 can, for example, be or comprise one or more metal sheets or plates, wherein the first busbar element 31 and the second busbar element 32 are electrically insulated from each other, for example by an electrically insulating sheet between them. Furthermore, the first busbar element 31, as for example in Fig. Figure 6B shows connecting parts 310 that are directly connected to the first capacitor terminals 11, and the second busbar element 32 has connecting parts 320 that are directly connected to the second capacitor terminals 12. These direct connections can be, in particular, direct mechanical connections. Additionally, the busbar elements 31 and 32 have external connecting parts 311 and 321 for connecting the busbar 30 to the DC power source.

[0046] Furthermore, the busbar 30 comprises a portion forming an overlapping section 33, which overlaps at least a portion of the at least one first conductor track 15 and / or the first capacitor terminal 11 and a portion of the at least one second conductor track 16 and / or the second capacitor terminal 12. Both the first and the second busbar elements 31, 32 can have such an overlapping section 33.

[0047] As in another embodiment in Fig. As shown in Figure 7, the busbar 30 can also include a thermal section 34, which can improve the cooling of the capacitor units 10. At least one or both of the first and second busbar elements 31, 32 can include such a thermal section 34. As described below, the thermal section 34 can, for example, be in thermal contact with a cooling unit of the semiconductor units. Consequently, the heat generated in the capacitor units 10 can be transferred to the cooling unit via the thermal section 34.

[0048] The in the Fig. The DC connection part shown in sections 6A to 7 can be combined with the semiconductor units 20 to form the Fig. To complete the electronic assembly shown in section 100. Fig. Figures 8A to 8C show a view from the underside, a side view and a partial view of the electronic assembly 100 with the DC connection part of the Fig. 6A to 6E and three semiconductor units 20 on a cooling unit 40, wherein the cooling unit 40 is in Fig. 8A is not shown. For example, in Fig. As can be seen in 8C, the busbar 30 can be in thermal contact with the cooling unit 40 via a so-called gap pad 50 made of a thermally conductive plastic material.

[0049] For each phase of the electronic assembly 100, i.e., for each pair of a capacitor unit 10 and a semiconductor unit 20, the first capacitor terminal 11, the first semiconductor terminal 21, and the first busbar element 31, in particular a first connecting part 310 of the first busbar element 31, are directly connected to each other, and the second capacitor terminal 12, the second semiconductor terminal 22, and the second busbar element 32, in particular a second connecting part 320 of the second busbar element 32, are directly connected to each other. Consequently, for each phase, the capacitor unit 10, the semiconductor unit 20, and the busbar 30 are directly connected to each other.As explained in the general section, a first element, selected from the capacitor terminals 11, 12, the semiconductor terminals 21, 22, and the busbar elements 31, 32, is in direct mechanical contact with the other two elements, such that the first element is preferably arranged between the other two elements, forming a sandwich-like structure in which the first element is embedded between the other two elements. The contact area of ​​the sandwich-like first element with one of the other two elements and the contact area of ​​the sandwich-like first element with the other of the other two elements preferably overlap when viewed along the stacking direction of the three elements, so that preferably the same part of the first element has direct mechanical contact with one of the other two elements.The direct connection can comprise one or more screw connections, a soldered connection, or a welded connection. For example, for each phase, the first busbar element 31, in particular a first connecting part 310, is arranged between the first capacitor terminal 21 and the first semiconductor terminal 21, and the second busbar element 32, in particular a second connecting part 320, is arranged between the second capacitor terminal 12 and the second semiconductor terminal 22. Alternatively, it is also possible that the first capacitor terminal 11 is arranged between the first busbar element 31 and the first semiconductor terminal 21, and that the second capacitor terminal 12 is arranged between the second busbar element 32 and the second semiconductor terminal 22.Furthermore, it is also possible that the first semiconductor terminal 21 is arranged between the first busbar element 31 and the first capacitor terminal 11, and that the second semiconductor terminal 22 is arranged between the second busbar element 32 and the second capacitor terminal 12.

[0050] Thus, the capacitor terminals 11, 12 of each capacitor unit 10 can be directly connected to the semiconductor terminals 21, 22 of a semiconductor unit 20, with the busbar elements 31, 32 being arranged on both sides of this stack or between the capacitor terminals 11, 12 and the semiconductor terminals 21, 22.

[0051] The Fig. 10A and Fig. Figure 10B shows in two views a further embodiment of an electronic assembly 100 in which two capacitor units 10 are directly connected to a respective semiconductor unit 20. In this case, the two capacitor units 10 can be connected to the semiconductor terminals 21, 22 on one side or on both sides, with the busbar elements 31, 32, for example, being arranged between them. In the embodiment of Fig. 10A and Fig. 10B, the thermal part 34 is used for cooling by convection to the surrounding atmosphere.

[0052] Fig. Figure 11 shows a further embodiment of the electronic assembly 100, in which, in contrast to the embodiment of the Fig. 10A and Fig. 10B the thermal part 34 is in thermal contact with a heat sink 40 for cooling the semiconductor units 20.

[0053] In the electronic assembly 100, as described in the figures, the DC link solution can be limited to one or two capacitor units 10 per semiconductor unit 20. The capacitor units 10 are independent of each other but have a common connection via the DC bus 30. The distance between the semiconductor units 20 and the capacitor units 10 is reduced as much as possible, and there is no intermediate connection element that indirectly connects the capacitor units 10 and the semiconductor units 20. The spatial proximity of the capacitor units 10 and the semiconductor units 20 helps to reduce the overall loop inductance. The bus 30 can be easily thermally connected to a semiconductor cooling system, e.g., via a thermal component 34 and / or a gap pad 50, thereby improving heat dissipation from the capacitor units 10.

[0054] The inverter input of the electronic assembly 100 is decoupled into two independent parts. It has a single DC busbar 30, through which the DC current flows exclusively, although AC current can also flow through the busbar 30 due to the current flow between the half-bridges. The busbar 30 also has a support element 13 for the capacitor units 10, with the current flow in the circuit boards of the support element 13 being the AC current due to the capacitor units 14. The busbar 30 can additionally be used to dissipate heat from the capacitor units 10 and can be cooled with air or by another method, including connecting the busbar 30 to the cooling unit 40 of the semiconductor units 20 via a thermal component or other heat sink. As a result, the DC current does not flow through the capacitor units 10.The busbar 30 serves as a connection for all capacitor units 10 to form the DC intermediate circuit and is directly connected to all capacitor units 10 and all semiconductor units 20.

[0055] The described design allows for a reduction in the amount of copper used on the DC side compared to standard solutions with a common copper busbar for the DC currents and all capacitors. Furthermore, the DC current cannot heat the circuit boards of the capacitor units 10, particularly the traces 15 and 16, because the DC current does not flow through the circuit boards but only generates heat at the connection points between the capacitor units 10 and the semiconductor units 20. This thermal decoupling can be particularly advantageous at high DC currents. The busbar 30 can be positioned between the semiconductor terminals 21 and 22 and the capacitor terminals 11 and 12 to further improve thermal decoupling.

[0056] The ability to change the position of the outer connection parts 311, 321 of the busbar 30, i.e., the outer terminals of the busbar, allows the DC link solution to be easily adapted to the footprint of any inverter. Since the busbar 30 is independent of the capacitor units 10 and directly connected to the semiconductor units 20, the busbar design can be more easily adapted to the space requirements of the inverter. The dimensioning of the busbar 30 is also simpler. The busbar 30 can be adapted in various ways depending on the heat dissipation requirements and the space requirements of the inverter and, in particular, the semiconductor units. With double-sided cooled semiconductor units 20, each polarity of the busbar 30 can be cooled by either of the semiconductor unit cooling units via a thermal component or a heat sink.It is also possible to cool only one of the busbar polarities. Furthermore, the thermal component can be adapted to the dimensions of the cooling unit. Additionally, it is possible to route one, several, or all busbar sections beneath the cooling unit to cool them with a thermal component or heat sink.

[0057] The outer terminals 311, 321 of the busbar 30 can be arranged in a perpendicular or parallel plane with respect to the support elements 13 of the capacitor units 10. The busbar 30 can be extended parallel to the support elements 13 by means of an overlapping section 33 in order to overlap it with the capacitor terminals 11, 12 or at least partially with the conductor tracks 15, 16. This overlap improves the electrical properties of the entire intermediate circuit, consisting of the capacitor units 10 and the busbar 30, particularly at high frequencies. The mutually induced flux causes a current in the opposite direction, thereby reducing the overall ESR and ESL.

[0058] The invention is not limited by the description based on the exemplary embodiments. Rather, the invention encompasses every new feature and also every combination of features, which in particular includes every combination of features from the claims, even if this feature or this combination itself is not expressly specified in the claims or exemplary embodiments. Reference sign 10 capacitor units 11, 12 Capacitor connection 13 Support element 14 Capacitor element 15, 16 conductor track 17 Contact pin 18 cases 20 semiconductor units 21, 22, 23 Semiconductor connection 30 busbar 31, 32 Busbar element 33 Overlapping part 34 Thermal part 40 cooling units 50 gap cushions 90 DC power source 91 AC load 100 electronic assemblies 110, 120 contact part 141, 142 Contact area 310, 320 Connecting part 311, 321 External connecting parts

Claims

[1] Electronic assembly (100), comprising - a capacitor unit (10) with at least two capacitor elements (14) on a support element (13) formed by a printed circuit board with a first capacitor terminal (11) and a second capacitor terminal (12). - a semiconductor unit (20) with a first semiconductor terminal (21) and a second semiconductor terminal (22), and - a busbar (30) with a first busbar element (31) and a second busbar element (32), wherein - the first capacitor terminal, the first semiconductor terminal and the first busbar element are directly connected to each other and the second capacitor terminal, the second semiconductor terminal and the second busbar element are directly connected to each other, so that the capacitor unit, the semiconductor unit and the busbar are directly connected to each other. [2] Electronic assembly according to claim 1, wherein the first busbar element is arranged between the first capacitor terminal and the first semiconductor terminal, and the second busbar element is arranged between the second capacitor terminal and the second semiconductor terminal. [3] Electronic assembly according to claim 1 or 2, wherein the electronic assembly comprises two capacitor units, wherein the two capacitor units, the semiconductor unit and the busbar are directly connected to each other. [4] Electronic assembly according to claim 3, wherein each capacitor unit comprises a first capacitor terminal and a second capacitor terminal and wherein the first semiconductor terminal is arranged between the first capacitor terminals of the two capacitor units and the second semiconductor terminal is arranged between the second capacitor terminals of the two capacitor units. [5] Electronic assembly according to one of the preceding claims, wherein the semiconductor unit is directly connected to exactly one or exactly two capacitor units. [6] Electronic assembly according to one of the preceding claims, wherein - the electronic assembly comprises a plurality of capacitor units and a plurality of semiconductor units, - at least one capacitor unit, one semiconductor unit and the power rail for each of the capacitor units and semiconductor units are directly connected to each other. [7] Electronic assembly according to one of the preceding claims, wherein each of the at least two capacitor elements is a metallized film capacitor element. [8] Electronic assembly according to one of the preceding claims, wherein all capacitor elements of the capacitor unit are electrically connected in series or in parallel with each other. [9] Electronic assembly according to any one of the preceding claims, wherein - each of the at least two capacitor elements has a first contact surface (141) and a second contact surface (142) which faces away from the first contact surface, - the first contact surfaces of all capacitor elements are electrically connected to the first capacitor terminal and the second contact surfaces of all capacitor elements are electrically connected to the second capacitor terminal, - the first contact surface of at least one of the at least two capacitor elements is opposite the second contact surface of a directly adjacent one of the at least two capacitor elements. [10] Electronic assembly according to one of the preceding claims, wherein the capacitor unit comprises more than two capacitor elements arranged in a series, such that for each pair of directly adjacent capacitor elements of the more than two capacitor elements a first contact surface of one of the pair of directly adjacent capacitor elements is opposite a second contact surface of the other of the pair of directly adjacent capacitor elements. [11] Electronic assembly according to any of the preceding claims, wherein - the carrier element has at least one first conductor track (15) that is electrically connected to the first capacitor terminal, and at least one second conductor track (16) that is electrically connected to the second capacitor terminal, - where at least one first conductor track and at least one second conductor track overlap at least partially. [12] Electronic assembly according to claim 11, wherein an overlapping part (33) of the busbar overlaps at least a part of the at least one first conductor track and / or the first capacitor terminal and a part of the at least one second conductor track and / or the second capacitor terminal. [13] Electronic assembly according to claim 11 or 12, wherein the carrier element comprises a plurality of first conductor tracks and a plurality of second conductor tracks arranged alternately one above the other and all overlapping each other. [14] Electronic assembly according to one of the preceding claims, wherein the at least two capacitor elements are housed in a common housing (19) on the support element. [15] Electronic assembly according to claim 14, wherein the housing comprises a housing filled with a resin. [16] Electronic assembly according to one of the preceding claims, wherein the busbar comprises a thermal part (34) which is in thermal contact with a cooling unit (40) of the semiconductor unit. [17] Electronic assembly according to any of the preceding claims, wherein the electronic assembly is at least part of an inverter device. [18] Electronic assembly according to one of the preceding claims, wherein the capacitor unit is a DC link capacitor.

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