Electronic power assembly having improved design
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-07-03
- Publication Date
- 2026-03-18
AI Technical Summary
High power density and package density in electronic power assemblies lead to mechanical stress on sensitive components due to tight installation tolerances, which can result in damage, and existing solutions like reducing tolerances or using cables are costly or impractical.
An electronic power assembly design featuring connector sockets arranged in a socket bracket attached to a mechanical support element, with an insulating structure between the circuit board and support element, allowing for tolerance compensation and minimizing mechanical stress through precise mechanical and electrical contact.
This design effectively avoids or minimizes elastic deformations and mechanical stress on critical components, enabling higher power density without component damage, while maintaining reliable electrical contact and simplifying assembly.
Smart Images
Figure EP2024068721_06022025_PF_FP_ABST
Abstract
Description
[0001] Description
[0002] Electronic power module with improved design
[0003] The present invention is based on an electronic power module, in particular a converter unit,
[0004] - wherein the power module comprises a printed circuit board with a top side and a bottom side,
[0005] - wherein the printed circuit board has conductor tracks for conducting power currents,
[0006] - wherein the circuit board has a number of recesses,
[0007] - threaded screws are guided through the recesses so that the screw heads of the threaded screws rest on the top side of the circuit board and the threads of the threaded screws protrude beyond the underside of the circuit board,
[0008] - where the threads are screwed into plugs of connectors for transmitting power currents so that the plugs are pressed against the underside of the printed circuit board,
[0009] - where the plugs are inserted into sockets.
[0010] Such power modules are well known. They are used, for example, as power supply units for electric drives.
[0011] Threaded screws can be used for a variety of purposes, for example, for the (exclusively) mechanical fastening of a circuit board in a housing or for contacting electrical connections. While electrical contact also creates a mechanical connection, this is not the purpose of electrical contact.
[0012] In technology, there is a general effort to fit more and more content into less and less space. In the case of electronic power assemblies, this means that the packaging density and power density are increased accordingly. Due to the increase in packaging density and power density, components, mechanical connections, electrical connections and contact points are moving ever closer together. In conjunction with unavoidable installation tolerances and other tolerances, this can lead to high mechanical stresses acting on sensitive components such as circuit boards or power semiconductor modules in small areas. Such mechanical stresses can lead to damage in the long term and should therefore be avoided as far as possible.
[0013] In the current state of the art, mechanical stresses are often acceptable because the geometric distances between components, mechanical and electrical connections, and contact points are sufficiently large. However, with the increasing increase in power density, the elastic deformation that can be tolerated is very small.
[0014] One possible solution to this problem is to work with tighter tolerances. However, this solution is very costly and is therefore rarely used in practice.
[0015] Another option is to use cables for electrical connections. Cables are flexible, so they can also compensate for tolerances. However, cables are difficult to process. In particular, automated production is often not possible.
[0016] An electronic power module of the type mentioned above is known from WO 2023 / 001330 A1. A similar disclosure can be found in US 2019 / 0371509 A1.
[0017] The object of the present invention is to further develop an electronic assembly of the type mentioned at the outset in such a way that, despite a high packing density and power density, elastic deformations of critical components can be completely or at least largely avoided.
[0018] The problem is solved by an electronic power module having the features of claim 1. Advantageous embodiments of the electronic power module are the subject of dependent claims 2 and 3.
[0019] According to the invention, an electronic power module of the type mentioned at the outset is designed in such a way that
[0020] - that the plug sockets are arranged in a socket holder, which in turn is attached to a mechanical support element for the socket holder arranged below the printed circuit board,
[0021] - that the socket holder is attached to the side of the mechanical support element facing away from the circuit board and
[0022] - that an insulating structure is arranged between the printed circuit board and the mechanical support element, which structure electrically insulates the printed circuit board from the support element.
[0023] The interaction of the threaded screws with the connectors also ensures that the screw heads are pressed against the top and the connectors against the underside of the circuit board. This ensures that the connectors, in particular, are mechanically fixed precisely (free of play). If electrical contact is to be established with the top and / or underside of the circuit board, good electrical contact is also guaranteed.
[0024] The use of plugs and sockets results in a direct tolerance compensation between the arrangement of the circuit board on the one hand and the arrangement of the socket holder on the other. This is because, regardless of whether a plug is fully or only partially inserted into a socket, good electrical contact is achieved between the plug and socket. An exception can only arise if the plug is only minimally inserted into the socket. However, this situation can be neglected within the scope of the present invention.
[0025] Due to the arrangement of the insulating structure between the circuit board and the mechanical support element, electrical clearance and creepage distances can be maximized. The insulating structure is usually made of plastic.
[0026] The power currents carried by the conductor tracks on the printed circuit board and also the power currents transmitted via the plug connections are generally 10 A or more. They are often 100 A or more, sometimes several hundred A, and in extreme cases even more than 1 kA. Switching elements for switching the power currents are usually arranged either directly on the printed circuit board or on a substrate which in turn is arranged on the top or bottom of the printed circuit board. The switching elements are generally used to switch voltages of 100 V and more, usually voltages of several hundred V, in some cases even voltages above 1 kV, in extreme cases up to 3.0 kV or 3.3 kV. The potential that a particular conductor track of this type or a particular plug connection has or carries can vary to the same extent over time.
[0027] Plug connectors suitable for carrying the required power currents are known. For example, see DE 10 2021 119 087 A1.
[0028] Preferably, a minimum spacing between immediately adjacent receptacles in the receptacle holder is smaller than the outer diameter of the receptacles. This maximizes the number of receptacles that can be arranged in a given space.
[0029] Preferably, at least four plug sockets are arranged in a row next to one another in the socket holder. The advantages of the present invention are particularly evident in such a situation. Typically, the connecting elements, regardless of whether they are designed as plug sockets or otherwise, can only be arranged within the socket holder itself with relatively high tolerances. Therefore, even with just a few plug sockets, if the connecting elements were designed differently, completely unacceptable mechanical distortion of the circuit board would often result.
[0030] The number of sockets is often six. This is because there are often three phases, and each choke is connected to a corresponding current path via two sockets.
[0031] The above-described properties, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more readily understood in connection with the following description of the embodiments, which are explained in more detail in conjunction with the drawings. Herein, in schematic representation:
[0032] FIG 1 Components of an electronic power module from the side,
[0033] FIG 2 is a plan view of a printed circuit board,
[0034] FIG 3 shows a detail of FIG 1 from a direction indicated in FIG 1 by II I- III and
[0035] FIG 4 a single plug connection .
[0036] According to FIG 1, an electronic power module has a printed circuit board 1. The power module can be a converter unit, for example. The printed circuit board 1 has (see FIG 3) a top side 2 and a bottom side 3. The printed circuit board 1 also has, according to FIG 2, conductor tracks 4. The conductor tracks 4 are used to carry power currents. They can be arranged on the top side 2 and / or on the bottom side 3 of the printed circuit board 1 as required. Only a few of the conductor tracks 4 are shown in FIG 2, and only sections of the conductor tracks 4 shown are also shown.
[0037] The printed circuit board 1 often also has additional conductor tracks that carry control signals. These additional conductor tracks are not relevant here. They are therefore not shown and will not be discussed below.
[0038] The printed circuit board 1 also has - see in particular FIG 3 - a number of recesses 5. Threaded screws 6, which have screw heads 7 and threads 8, are guided through the recesses 5. The screw heads 7 lie against the upper side 2 of the printed circuit board 1. The threads 8 of the threaded screws 6 protrude beyond the underside 3 of the printed circuit board 1. In particular, the threads 8 are screwed into plugs 9, which, as shown in FIG 4, have corresponding threaded holes 10 for this purpose. As a result, the plugs 9 are pressed against the underside 3 of the printed circuit board 1. At the same time, the screw heads 7 are also pressed against the upper side 2 of the printed circuit board 1.
[0039] The plugs 9, in turn, are inserted into plug sockets 11. The plug sockets 11, together with the plugs 9, each form a plug connection for transmitting a power current. The plug sockets 11 are arranged in a socket holder 12. For example, the plug sockets 11, as shown in FIG 4, can have a thread 13 on their underside with which they are screwed into the socket holder 12. The socket holder 12 is fastened by means of fastening elements 14 to a mechanical support element 15 for the socket holder 12. The mechanical support element 15 is arranged below the printed circuit board 1.
[0040] 1 to 3 show the finished state of the electronic power module. To manufacture the electronic power module, it is possible to first fasten the plugs 9 to the underside 3 of the printed circuit board 1 using the threaded screws 6 and then to guide the printed circuit board 1 such that the plugs 9 are inserted into the plug sockets 11. At this point in time, the plug sockets 11 are already arranged in the socket holder 12 and the socket holder 12 is already fastened to the support element 15. However, a different procedure is preferably taken. The arrangement of the plug sockets 11 in the socket holder 12 and the fastening of the socket holder 12 to the support element 15 remain unchanged. However, the plugs 9 are arranged in the plug sockets 11. The printed circuit board 1 is then placed onto the completed plug connections.Only then are the threads 8 of the threaded screws 6 screwed into the threaded holes 10 .
[0041] According to FIG 4, the plug sockets 11 have an outer diameter D . The outer diameter D is the diameter which the plug sockets 11 have, viewed in a plug-in direction of the plugs 9, in the area into which the plugs 9 are inserted. Furthermore, immediately adjacent plug sockets 11 are arranged in the socket holder 12 in a grid dimension R . The grid dimension R is the distance from the center of one plug socket 11 to the center of the next plug socket 11. According to the illustration in FIG 4, the grid dimension R can be less than twice the diameter D . In this case, immediately adjacent plug sockets 11 have a minimum distance RD from one another which is less than the outer diameter D.
[0042] Furthermore, according to FIG 3, at least four - specifically even six - plug sockets 11 are arranged next to one another in a row in the socket holder 12.
[0043] It can also be seen, in particular, from FIG. 3 that an insulating structure 16 is arranged between the circuit board 1 and the mechanical support element 15. The insulating structure 16 electrically insulates the circuit board 1 from the support element 15. FIG. 1 shows the entire power module. In particular, FIG. 1 shows further components in addition to the components explained so far. These components do not all have to be present and are of secondary importance within the scope of the present invention.
[0044] For example, the power module may include the following additional components:
[0045] - Power modules 17, by means of which the power currents are switched. The power modules 17 comprise switching elements such as transistors or thyristors. The precise design of the transistors or thyristors can be as required, for example, in the case of transistors, as bipolar transistors, as IGBTs, or as FETs.
[0046] - A heat sink 18 for cooling the power modules 17 .
[0047] - Buffer capacitors 19, usually in the form of electrolytic capacitors. The buffer capacitors 19 generally fulfill the function of intermediate circuit capacitors in a DC voltage circuit.
[0048] - A mechanical bridge structure 20, which is fastened to the printed circuit board 1. The bridge structure 20 consists of an electrically insulating material, in particular a plastic. The fastening can be carried out as required. The bridge structure 20 has a support surface on its upper side.
[0049] - An additional unit 21 arranged above the circuit board 1. The additional unit 21 has electronic components (not shown). The electronic components can, for example, form a filter circuit commonly found in converter units. The additional unit 21 rests on the support surface of the bridge structure 20.
[0050] - A connection block 22 for external wiring, for example to an electrical machine.
[0051] - Additional elements 23 integrated into the current guide of the electronic power module. The additional elements 23 can be designed, in particular, as chokes. In particular, the integration of such additional elements 23 can be achieved via the plug connections. The present invention has many advantages. In particular, mechanical stresses can be completely or at least almost completely avoided in a simple manner. Furthermore, the assembly of the electronic power module is simplified.
[0052] Although the invention has been illustrated and described in detail by the preferred embodiment, the invention is not limited to the disclosed examples and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.
Claims
Patent claims 1. Electronic power module, in particular converter unit, - wherein the power module comprises a printed circuit board (1) with a top side (2) and a bottom side (3), - wherein the printed circuit board (1) has conductor tracks (4) for conducting power currents, - wherein the circuit board (1) has a number of recesses (5), - wherein threaded screws (6) are guided through the recesses (5) so that screw heads (7) of the threaded screws (6) rest on the upper side (2) of the printed circuit board (1) and threads (8) of the threaded screws (6) protrude beyond the underside (3) of the printed circuit board (1), - wherein the threads (8) are screwed into plugs (9) of plug connections for transmitting power currents, so that the plugs (9) are pressed onto the underside (3) of the printed circuit board (1), - wherein the plugs (9) are inserted into plug sockets (11), characterized in that - that the plug sockets (11) are arranged in a socket holder (12), which in turn is fastened to a mechanical support element (15) for the socket holder (12) arranged below the printed circuit board (1), - that the socket holder (12) is attached to the side of the mechanical support element (15) facing away from the printed circuit board (1) and - that an insulating structure (16) is arranged between the printed circuit board (1) and the mechanical support element (15), which structure electrically insulates the printed circuit board (1) from the support element (15).
2. Power module according to claim 1, characterized in that a minimum distance between immediately adjacent plug- sockets (11) in the socket holder (12) is smaller than an outer diameter (D) of the plug sockets (11).
3. Power module according to claim 1 or 2, characterized in that at least four plug sockets (11) are arranged next to one another in a row in the socket holder (12).