Power electronic device and motor vehicle with power electronic device

Abstract

The invention relates to a power electronic device (10) comprising a printed circuit board (12) and a power electronic module (14), wherein the power electronic module (14) has contact pins (16) which are guided through holes (18) in the printed circuit board (12). The power electronic device (10) has a metallic mounting support (20) to which the module (14) and the printed circuit board (12) are fastened and which is arranged between the printed circuit board (12) and the module (14). The power electronic device (10) has a flat insulating element (22) which is arranged between the printed circuit board (12) and the mounting support (20), wherein the insulating element (22) has insertion aids (24) for aligning the contact pins (16) with the holes (18) in the printed circuit board (12) during assembly of the power electronic device (10).

Description

[0001] The invention relates to a power electronic device and a motor vehicle with such a power electronic device.

[0002] Power electronic devices of the type in question can be used to supply power to an electric drive, for example, a motor vehicle. These electric drives can be the traction drives of motor vehicles. Due to the power densities prevalent in such applications, special designs are necessary in practice that take into account the requirements of mechanical durability, electromagnetic compatibility, and heat dissipation.

[0003] The resulting design challenges are further exacerbated by the desire for the power electronics device to be as simple and automated as possible for assembly.

[0004] In the past, several detailed solutions have therefore emerged to overcome the challenges that arise when assembling such power electronic devices.

[0005] For example, DE 10 2019 219 282 A1 discloses a power converter for a vehicle with a printed circuit board, in which the printed circuit board is connected to at least one component via several pins. The printed circuit board has a centering aid for each pin on a side facing the component. The centering aids make it easier for the pins to enter the respective holes during assembly of the power converter by guiding the pins to their respective holes through the centering aid.

[0006] WO 2012 / 085397 A1 discloses a similar centering aid. The centering aid extends flat between the component and the circuit board and has a plurality of funnel-shaped guide areas for guiding a plurality of pins to their assigned holes in the circuit board.

[0007] Furthermore, EP 3 177 123 B1 shows a voltage converter in which an electronics board is arranged on a carrier. The electronics board is connected to a component arranged on the side of the carrier facing away from the electronics board by means of a plug-in contact. The carrier has guide elements for guiding the plug-in contacts to the corresponding receptacle contacts of the electronics board.

[0008] The invention is based on the object of demonstrating a power electronic device which further develops the known power electronic devices in such a way that additional functionalities can be integrated in the area of the interface between a printed circuit board and a power electronic module while at the same time being easy to assemble.

[0009] The problem is solved by a power electronic device and a motor vehicle with such a power electronic device according to one of the independent claims. The features of the dependent claims relate to advantageous embodiments.

[0010] The power electronics device comprises a printed circuit board and a power electronics module. The power electronics module has contact pins. The contact pins are routed through holes in the circuit board to make contact with the printed circuit board.

[0011] The contact pins serve to electrically connect the power electronics module to the circuit board. The contact pins can be so-called press-fit pins. Press-fit pins are contact pins designed in such a way that the cross-section of the press-fit pin can be reduced by elastic deformation when the pin is inserted through a suitable opening. Due to the elastic restoring forces, the press-fit pins can be held force-fittingly in a suitably dimensioned opening into which they have been inserted, generating elastic deformation of the press-fit pin. The contact forces acting as part of the force-fitting connection also create an intimate electrical contact, which makes press-fit pins ideal for use in power electronics of the type in question.

[0012] The power electronics device comprises a metal mounting support to which the module and circuit board are attached and which is arranged between the circuit board and the module. Such a mounting support offers the possibility of combining several functions in a single component. First, such a metal mounting support provides a robust mounting option for the circuit board and the power electronics module.

[0013] Furthermore, a metal mounting support offers good thermal conductivity, which is why the mounting support contributes to heat dissipation from the area between the circuit board and the power electronics module. Power electronics modules in particular often generate considerable amounts of heat energy. The improved heat dissipation from the area between the circuit board and the power electronics module, which can be achieved with the metal mounting support, reduces the risk of this heat having a harmful effect on the circuit board or the electronic components arranged on the circuit board.

[0014] Furthermore, a metallic mounting support can be used to improve electromagnetic compatibility. Power electronic modules, in particular, are critical components with regard to their electromagnetic compatibility. A metallic mounting support is suitable for shielding electromagnetic interference, which can emanate particularly from the power electronic module, from the circuit board and / or the environment.

[0015] Furthermore, the power electronic device comprises a flat insulating element arranged between the circuit board and the mounting support. Such a flat insulating element serves to meet the requirements for clearance and creepage distances that exist to ensure sufficient electrical insulation between the metallic mounting support and the circuit board.

[0016] The printed circuit board and the mounting support can extend flatly in mutually parallel planes. The flat insulation element can also extend flatly in a plane parallel to the plane of the mounting support and / or the printed circuit board. This results in an overall compact "layered" structure that is easy to assemble and benefits mechanically, thermally, and electromagnetically from the combination of the metallic mounting support and the insulation element.

[0017] The insulation element also features insertion aids for aligning the contact pins with the holes in the circuit board during assembly of the power electronic device. The advantage of ensuring the necessary electrical insulation between the circuit board and the metallic mounting support with a flat insulation element is that the insulation element can also be used to align the contact pins with the holes in the circuit board during assembly of the power electronic device. Combining the electrical insulation and insertion aids in a single component also results in very simple assembly of the power electronic device, since comparatively few elements need to be connected during assembly.The resulting power electronic device is therefore characterized not only by its robust and compact design, which is made possible in particular by the metallic mounting support, but also by its easy installation, which is made possible by the flat insulation element with the insertion aids.

[0018] The power electronic device can be a pulse-controlled inverter for supplying an electric drive with electrical energy. Such pulse-controlled inverters can fully exploit the specific advantages resulting from the power electronic device design described above. In particular, the thermal and electromagnetic advantages provided by the metallic mounting support come into play with such a design.

[0019] In particular, the module can contain a power switch of the pulse-controlled inverter. Such power switches pose challenges both in terms of heat generation and electromagnetic compatibility. Furthermore, high voltages typically occur at the electrical interface between the circuit board of a power electronic device and the module containing the power switch, which must be managed by suitable insulation. The design with the flat insulation element is particularly suitable for this.

[0020] The module can be a molded module. In molded modules, an electronic component, which can in particular be the power switch of the pulse-controlled inverter, is encapsulated in a molding compound. Molded modules are particularly suitable for connecting to printed circuit boards via contact pins, particularly press-fit pins. The use of insertion aids in conjunction with the molded module is particularly advantageous, as molded modules typically have certain tolerances regarding the alignment of their contact pins.

[0021] The module preferably also has a flat shape. The module's flat extension is aligned parallel to the flat extension of the mounting support and, in particular, the insulating element and / or the circuit board. Such an alignment enables a compact design of the power electronic device and also facilitates effective cooling of the module. The mounting support can contribute to cooling on one side of the module, while a cooling device for cooling the mold can advantageously be arranged on the other side.

[0022] The contact pins extend, in particular, from one of the surface sides of the module at, at least substantially, a right angle away from the module. Although modules with such an alignment of the contact pins are advantageous with regard to an overall compact design of the power electronic device, since the contact pins are located between the components of the power electronic device when the power electronic device is assembled and are inaccessible from the outside, it is difficult to ensure their precise alignment during assembly by using tools that engage the contact pins. Therefore, insertion aids on the insulation element are particularly advantageous for modules designed in this way.

[0023] The insertion aids can be formed as passages tapering toward the circuit board. Such passages tapering toward the circuit board are suitable for correcting the contact pin's exact spatial alignment as it approaches the circuit board during assembly of the power electronic device. The contact pin penetrates the tapered passage with its tip first and slides off the walls defining the passage, guiding the tip of the contact pin toward the hole in the circuit board. The passages can, in particular, be designed in a funnel shape. A funnel-shaped design allows deviations of the contact pin from its ideal position to be corrected in any direction within the plane of extension of the insulation element.

[0024] The power electronic device can have a power zone and a control zone. A control zone is the zone of the circuit board where the power electronic components that directly intervene in the electrical energy flow are located. Particularly if the power electronic device is a pulse-controlled inverter, the power section of the pulse-controlled inverter is located in the power zone. In contrast, the control zone contains the electronic components that serve to control the power section or the power electronic components located in the power zone on the signal side.

[0025] In particular, the voltages occurring in the control zone are below a limit value that is exceeded by the voltage occurring in the power zone. The different voltage levels in the control zone and the power zone result in the respective requirements for electrical insulation, particularly with regard to clearances and creepage distances.

[0026] The highest voltage occurring in the control zone can be below 50 V, in particular below 20 V. Alternatively and / or additionally, the highest voltage occurring in the power zone can be above 200 V, in particular above 500 V. Such voltage levels make it possible, for example, to design the voltage in the control zone to be compatible with the 12 V on-board network of a motor vehicle and to enable correspondingly low requirements with regard to electrical insulation within the control zone. On the other hand, the high voltage level in the power zone enables the power electronic device to provide high electrical power by means of comparatively small cross-sections of the electrical conductors required for this purpose.

[0027] The insulation element can extend only over a portion of the gap between the printed circuit board and the mounting support. This allows the mounting support and the printed circuit board to be directly adjacent in another portion of the gap between the printed circuit board and the mounting support. Directly adjacent mounting support and printed circuit board means, in particular, that the mounting support and the printed circuit board are separated from each other only by an air gap. Particularly when the printed circuit board has a power zone and a control zone, the insulation between the mounting support and the printed circuit board can typically be limited to the power zone.However, in other applications in which comparatively high voltage levels occur only in a partial area of the circuit board, the possibility of providing the insulation element only in the area of this partial area is also a possible advantageous design.

[0028] Accordingly, the portion of the intermediate space in which the insulating element extends can be spatially assigned to the power zone, while, in particular, the portion in which the mounting support and circuit board are directly adjacent or separated from each other only by an air gap can be spatially assigned to the control zone. In other words, the insulating element between the circuit board and the mounting support can extend only over a portion of the circuit board in which the power zone is located.

[0029] The insulation element can have centering elements that interact with complementary centering counter-elements of the circuit board to spatially align the insulation element relative to the circuit board. The centering elements can be, for example, centering elements that project from the insulation element toward the circuit board and engage in corresponding centering counter-elements of the circuit board designed as receptacles. In this case, the centering elements can taper towards the circuit board so that when the circuit board is connected to the insulation element, the insulation element is centered relative to the circuit board when the insulation element and circuit board are moved toward each other. In this context, centering is understood to mean, in particular, the spatial alignment with respect to the plane of extension of the insulation element and the circuit board.

[0030] The circuit board can have a plurality of power zones. The insulation element can have a plurality of flat, interconnected segments that are movable relative to one another. In particular, a segment of the insulation element can be arranged between each of the power zones and the mounting support. It is particularly advantageous if the circuit board has three power zones. The insulation element can accordingly have three segments. Each power zone can be assigned to a phase of an alternating voltage to be generated by the power electronic device.

[0031] Such designs have the advantage that each individual segment can have a smaller surface area than a single insulation element that extends flat across all power zones of the circuit board. This smaller surface area makes it easier to maintain tight tolerances regarding the spatial position, particularly of the holes and insertion elements relative to one another. The relatively movable connection allows for positional tolerances between the individual segments to be compensated for during assembly of the power electronic device.

[0032] The motor vehicle has an electric drive and a power electronics device according to the above description for supplying the electric drive of the motor vehicle with electrical energy. Electric drive systems of such motor vehicles require comparatively high electrical power. In addition, the power electronics devices installed in motor vehicles are subject to high demands on their robustness and reliability, while at the same time being subject to high cost pressure. The power electronics device described above can therefore be used particularly advantageously in motor vehicles. In particular, the possibility of comparatively robust fastening of the components via a metallic mounting support plays a prominent role with regard to the application-specific advantages of the power electronics device in a motor vehicle.

[0033] Further practical embodiments of the invention are described below in conjunction with the drawings. They show: Fig. 1 a schematic perspective view of an exemplary power electronic device, Fig. 2 the power electronic device from Fig. 1 without the circuit board, Fig. 3 the circuit board Fig. 1 with attached insulation element, Fig. 4 a schematic sectional view through the Fig. 1 power electronic device shown, Fig. 5+ Fig. 6 exemplary alternative insulation elements.

[0034] The Fig. The exemplary power electronic device 10 shown in FIGS. 1 to 4 comprises a printed circuit board 12 and a power electronic module 14. The power electronic module 14 has contact pins 16 that extend through holes 18 in the printed circuit board 12. The contact pins 16 can be press-fit pins, in particular. The contact pins 16 are received in the holes 18 of the printed circuit board 12, in particular with a force fit.

[0035] Furthermore, the power electronic device 10 has a mounting support 20. The power electronic module 14 and the printed circuit board 12 are attached to the metallic mounting support 20. As in the example shown, the printed circuit board 12 and the mounting support 20 can extend flatly in mutually parallel planes of extension.

[0036] The power electronic device 10 further comprises a planar insulation element 22. The planar insulation element 22 can, in particular, also extend planar in a plane parallel to the plane of extension of the mounting support 20 and / or the printed circuit board 12. In this way, the insulation element 22 extends, in particular, as shown in Fig. 4 can be seen in a space formed between the mounting bracket 20 and the printed circuit board 12.

[0037] The insulation element 22 has insertion aids 24 for aligning the contact pins 16 with the holes 18 in the printed circuit board 12 during assembly of the power electronic device 10.

[0038] The insertion aids 24 can, as particularly in the Fig. 4, can be designed as passages tapering towards the circuit board 12 and in this context can be designed in a funnel-like manner, in particular as in the example shown.

[0039] As in the example shown, the insulation element 22 can extend only over a portion of the gap between the circuit board 12 and the mounting support 20. This is particularly evident in the figures based on the Fig. 2 and Fig. 3, from which, due to the different perspectives chosen in Fig. 3 the relative position of the insulation element 22 to the circuit board 12 and in the Fig. 2 shows the relative position of the insulation element 22 to the mounting bracket 20.

[0040] From the comparison of the Fig. 2 and Fig. 3 also shows that, where the insulating element 22 does not extend between the mounting support 20 and the printed circuit board 12, the printed circuit board 12 and the mounting support 20 can be arranged directly adjacent and thus, as in the example shown, separated from each other only by an air gap. In a configuration corresponding to the example shown, a power zone of the printed circuit board 12 can, in particular, be arranged in a region of the printed circuit board 12 that is adjacent to the insulating element 22.

[0041] Based on the Fig. 5 and Fig. Further exemplary embodiments can be seen in the exemplary variants of the insulation element 22 shown in Figure 6. For example, as in the example shown there, the insertion aids 24 can have a square cross-section.

[0042] Also, as particularly in the Fig. 5 and Fig. 6, the insulating element 22 may have centering elements 26 in order to spatially align the insulating element 22 relative to the printed circuit board 12 during assembly.

[0043] The insulation element 22 can furthermore, as particularly in the Fig. 5 and Fig. 6, have integrally formed connecting elements 28. By means of such connecting elements 28, the insulation element 22 can be connected to the circuit board 12, for example by means of hot caulking.

[0044] As in the Fig. In the variant shown in Figure 6, the insulation element 22 can further comprise a plurality of movable, flat, and interconnected segments 30. As in the example shown, the individual segments 30 can be movably connected to one another by means of connecting links 32.

[0045] The features of the invention disclosed in the present description, the drawings, and the claims may be essential, both individually and in any combination, for the realization of the invention in its various embodiments. The invention may be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art. List of reference symbols 10 power electronic device 12 circuit board 14 power electronic module 16 contact pins 18 holes 20 mounting brackets 22 flat insulation element 24 Insertion aid 26 Centering element 28 Connecting element 30 segments 32 connecting link QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2019 219 282 A1

[0005] WO 2012 / 085397 A1

[0006] EP 3 177 123 B1

[0007]

Claims

[1] Power electronic device (10) with a printed circuit board (12) and a power electronic module (14), wherein the power electronic module (14) has contact pins (16), wherein the contact pins (16) are guided through holes (18) in the printed circuit board (12) for contacting the printed circuit board (12), wherein the power electronic device (10) has a metallic mounting support (20) to which the module (14) and printed circuit board (12) are fastened and which is arranged between the printed circuit board (12) and the module (14), wherein the power electronic device (10) has a flat insulating element (22) which is arranged between the printed circuit board (12) and the mounting support (20), wherein the insulating element (22) has insertion aids (24) for aligning the contact pins (16) with the holes (18) in the printed circuit board (12) during assembly of the power electronic device (10). [2] Power electronic device (10) according to claim 1, characterized by that the power electronic device (10) is a pulse-controlled inverter for supplying an electric drive with electrical energy, in particular wherein the module (14) contains a power switch of the pulse-controlled inverter. [3] Power electronic device (10) according to claim 1 or 2, characterized by that the insertion aids (24) are designed as passages tapering towards the circuit board (12), in particular as funnel-shaped passages. [4] Power electronic device (10) according to one of the preceding claims, characterized by that the contact pins (16) are press-fit pins. [5] Power electronic device (10) according to one of the preceding claims, characterized bythat the printed circuit board (12) has a power zone and a control zone, wherein the voltage occurring in the control zone is below a limit value which is exceeded by the voltage occurring in the power zone. [6] Power electronic device (10) according to claim 5, characterized by that the highest voltage occurring in the control zone is below 50V, in particular below 20V and / or the highest voltage occurring in the power zone is above 200V, in particular above 500V. [7] Power electronic device (10) according to one of the preceding claims, characterized bythat the insulation element (22) extends only over a partial area of the intermediate space between the printed circuit board (12) and the mounting support (20), in particular wherein the insulation element between the printed circuit board (12) and the mounting support (20) extends only over a partial area of the printed circuit board (12) in which the power zone is arranged. [8] Power electronic device (10) according to one of the preceding claims, characterized by that the insulating element (22) has centering elements (26) which interact with complementary centering counter-elements of the printed circuit board (12) for the spatial alignment of the insulating element (22) relative to the printed circuit board (12). [9] Power electronic device (10) according to one of the preceding claims, characterized bythat the printed circuit board (12) has a plurality, in particular three, power zones and the insulating element (22) has a plurality of flat and interconnected segments (30) which are movable relative to one another, and a segment (830) of the insulating element (22) is arranged between each of the power zones and the mounting support. [10] Motor vehicle with an electric drive and a power electronic device (10) according to one of the preceding claims for supplying the electric drive with electrical energy.

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