EMC input filter arrangement of a power electronics application in a vehicle

Abstract

Proposed is an EMC input filter arrangement for a power electronics application in a vehicle, comprising two adjacent magnetic cores, each with a top and a bottom and a central pass-through, the passes being arranged parallel to each other, a holder made of electrically non-conductive material forming a surface for receiving the bottom of the magnetic cores, and DC busbars comprising DC positive and DC negative busbars, which are formed in multiple parts. A first part is routed to the bottom of the first magnetic core, and a second part is routed away from the bottom of the second magnetic core.A third part is formed as an essentially U-shaped plug-in component, comprising two parallel legs. One leg of each leg extends from the top surface into a central opening in the associated magnetic core, reaching to the underside of the core, and is electrically contacted with the corresponding first or second part of the DC positive and DC negative busbars. The parallel legs are connected at their ends, facing away from the magnetic cores, by a third leg that runs parallel to the surface of the mounting. Furthermore, a printed circuit board is provided, positioned above the at least one magnetic core and extending over at least the area of ​​both magnetic cores. The underside of this board is parallel to the surface of the mounting, and the printed circuit board and DC busbars are electrically connected via conductive traces.

Description

[0001] The present invention relates to the field of electromobility, in particular to electronic modules for an electric drive.

[0002] The use of electronic modules, such as power electronics modules, in motor vehicles has increased significantly in recent decades. This is due, on the one hand, to the need to improve fuel economy and vehicle performance, and, on the other hand, to advances in semiconductor technology. The main component of such an electronic module is a DC / AC inverter, which is used to supply electrical machines such as electric motors or generators with multi-phase alternating current (AC). This involves converting direct current generated by a DC energy source, such as a battery or accumulator, into multi-phase alternating current. Due to the large number of components and the high-voltage components, there are recurring problems with EMC interference, which can lead to malfunctions or even complete failure of components.EMC stands for electromagnetic compatibility and describes the ability of devices to be robust or immune to electromagnetic interference and not to emit any such interference.

[0003] A recurring problem in inverter design is that, due to the modular design, many functions are integrated into separate functional modules, which then need to be combined. This also applies to the DC EMC input filter of the inverter module.

[0004] The invention is therefore based on the object of improving the design of the DC EMC input filter.

[0005] This problem is solved by the features of the independent claims. Advantageous embodiments are the subject of the dependent claims.

[0006] Proposed is an EMC input filter assembly for a power electronics application in a vehicle, comprising two adjacently arranged magnetic cores, each with a top side and a bottom side and a central passage, wherein the passages are arranged parallel to one another, a holder made of electrically non-conductive material that forms a surface for receiving the bottom side of the magnetic cores, and DC busbars comprising DC plus and DC minus busbars, which are formed in multiple parts. A first part is guided to the bottom side of the first magnetic core, and a second part is guided away from the bottom side of the second magnetic core.A third part is formed as a substantially U-shaped plug-in component such that two mutually parallel legs are formed, one of which is guided from the top side into a central passage of the associated magnetic core to its underside and is electrically contacted with the associated first or second part of the DC plus and DC minus busbars. The parallel legs are connected to one another at their end regions facing away from the magnetic cores via a third leg that is guided parallel to the surface of the holder. Furthermore, a printed circuit board is provided, arranged above the at least one magnetic core and extending over at least the surface of the two magnetic cores, the underside of which is parallel to the surface of the holder, wherein the printed circuit board and DC busbars are in electrical contact with one another via conductor tracks.

[0007] In one embodiment, screw points connectable to GND are provided at the outer end areas of the circuit board. In one embodiment, at least one X capacitor and at least one Y capacitor are arranged on the underside of the circuit board facing the holder. One terminal of the capacitor is connected to the associated DC power rail, and the other terminal is connected to GND via an associated connection point using conductor tracks in the circuit board.

[0008] In one embodiment, at least one current sensor for tapping current from the DC negative power rail is arranged on a top side of the circuit board opposite the bottom side. In one embodiment, contact springs are inserted into the circuit board at the outer end regions in such a way that they contact the corresponding DC power rails.

[0009] In one embodiment, the first, second and third parts of the DC busbars are at least partially surrounded by an electrically insulating overmolding.

[0010] In one embodiment, an electrically insulating carrier is also provided in which the cores are accommodated.

[0011] In one embodiment, the second part of the DC busbars is a portion of the second leg of the substantially U-shaped plug-in component.

[0012] In one embodiment, at least one buffer element for mechanical buffering is provided between the electrically insulating support and the third part of the DC busbars.

[0013] In one embodiment, the circuit board has at least one temperature sensor on its top side and X and Y capacitors on its bottom side.

[0014] Furthermore, an electronic module is provided, comprising the EMC input filter arrangement, and an inverter arrangement which is configured to convert a DC input current filtered by the EMC input filter into an AC output current.

[0015] Furthermore, an electric drive of a vehicle is provided, comprising the electronic module for controlling the electric drive.

[0016] Furthermore, a vehicle is provided having the electric drive.

[0017] Further features and advantages of the invention will become apparent from the following description of exemplary embodiments of the invention, with reference to the figures of the drawing, which illustrate details of the invention, and from the claims. The individual features can be implemented individually or in combination in a variant of the invention.

[0018] Preferred embodiments of the invention are explained in more detail below with reference to the accompanying drawings. Fig. Figure 1 shows a plan view of a DC EMC input filter section constructed according to the prior art. Fig. 2 shows a bottom view of the Fig. 1 shown DC EMC input filter range. Fig. 3 shows a plan view of a DC EMC input filter section according to an embodiment of the present invention. Fig. 4 shows a bottom view of the Fig. 3 shown DC EMC input filter range. Fig. 5 shows an exploded view of the Fig. 2 and Fig. 3 shown DC EMC input filter range.

[0019] In the following descriptions of the figures, the same elements or functions are provided with the same reference symbols.

[0020] The basic idea is to combine as many separate functional modules as possible in the DC EMC input filter area of ​​an inverter used for electric drives of vehicles in order to achieve simplified assembly and standardization of the DC EMC input filter area.

[0021] In Fig. Figures 1 (top view) and 2 (bottom view) show a DC EMC input filter area according to the prior art. DC input sockets 7 are shown here, which are electrically connected to corresponding DC busbars 2 (DC plus and DC minus), or DC busbars 2 for short. These DC busbars 2 lead to a populated circuit board 3, which, among other things, has a temperature sensor 31 and which has a signal connection to a board 9 in the area of ​​the inverter modules that convert the DC voltage into AC voltage. The circuit board 3 is arranged above the DC busbars 2, and from there, the DC busbars 2 lead to the area of ​​the cores 1 of the input filter. In the embodiment shown, two cores 1 are provided, through whose central passage 11 the DC busbars 2 are guided. The DC plus rail is of course electrically separated from the DC minus rail.The cores 1 are arranged in the DC EMC input filter area such that their passages 11 are arranged one behind the other and rotated essentially 90 degrees relative to the circuit board 3. This allows the DC busbars 2 to be routed straight through both passages 11, starting from the circuit board 3. An electrically insulating carrier 4, which can also be referred to as a housing, is provided around the cores 1. The cores 1 are also arranged at a distance from one another. In the area between the cores, a tap in the form of additional DC busbars 2.1 is provided on the DC busbars 2. This tap is routed from the top of the carrier 4 to its underside, where X and Y capacitors 8 are arranged (attached to the carrier 4). The X and Y capacitors 8 are attached with one contact leg to the additional DC rails 2.1 and with the other contact leg to screw points 30 that can be connected to GND, in short GND connections 30.

[0022] The cores 1 are generally formed as rings and have a circular cross-section. However, they can also have an oval or other cross-section, with a passage 11 always being provided in their center for the passage of the DC rails 2. Soft magnetic materials, e.g., ferrites or suitable nanocrystalline materials, are generally used as core materials. The latter have a significantly higher filtering effect and are therefore increasingly used. Nanocrystalline cores consist of a very thin strip material (sheet metal), which is wound or pressed into several layers and then baked. In the invention described below, the cores 1 are also formed as known from the prior art, i.e., in particular, as nanocrystalline cores 1.

[0023] In order to require as few separate components as possible, it is proposed according to the invention to guide the circuit board 3 completely over the cores, as in Fig. 3. It is also proposed to rotate the cores 1 by 90 degrees so that their passages 11 are parallel to one another (not facing one another) and point towards the circuit board 3, i.e. the top side of the cores 1 is parallel to the circuit board 3. The cores 1 are arranged on a flat holder 41 which lies on the DC rails 2 and has a central opening so that the DC rails can pass from the underside of the cores 1 through their passage 11 to the top side of the cores 1. The holder 41 is therefore parallel to the top side of the cores 1 and to the circuit board 3. This arrangement requires a different guidance of the DC rails 2. These still have to be routed from the DC input sockets 7 to the first core 1, then to the circuit board 3 and from there via the second core 1 towards the DC taps in the area of ​​the inverter modules (usually first to the intermediate circuit).For this purpose, the DC busbars 2 are divided into several sections in the design shown. One version is shown in the exploded view in . Fig. 5. In this version, a first part is led from the bottom to the first core 1 and ends in the middle area, i.e., the passage 11. A second part begins on the bottom and in the middle area, i.e., the passage 11, of the second core 1 and leads via the intermediate circuit capacitor to the DC taps in the area of ​​the inverter modules. Fig. 4 in the bottom view, where the electrically insulating overmolding 5 of the DC rails 2 and the underside of the holder 41 is also shown. The first and second parts of the DC rails 2 are electrically connected to each other via a third part. This third part is formed as a plug-in component that is essentially U-shaped, i.e., has two parallel legs that are connected to a cross-member via another leg, as shown in Fig. 5. The first leg is electrically contacted with the first part of the DC busbars 2 and from there runs vertically from the underside of the first core through the center of the first core 1 towards the underside of the circuit board 3, then runs in the area of ​​the underside of the circuit board 3 (cross-member-like). Then it (the second leg) runs vertically again through the passage 11 of the second core 1 to its underside, where it is electrically contacted with the second part of the DC busbars 2, which leads to the intermediate circuit capacitor and the DC taps. Alternatively, the second leg can be electrically contacted directly with the intermediate circuit capacitor and DC taps, depending on the arrangement. Thus, the second part of the DC busbars 2 is formed as a sub-region of the second leg of the plug-in component.The section of the third part of the DC rails 2, which runs along the underside of the circuit board 3, is rotated so that the larger surface of the DC rail 2 runs parallel to the underside, as shown in . Fig. 5 can be seen.

[0024] The electrical contact between the first and third and second and third parts of the DC rails 2 is made, for example, by laser welding.

[0025] The DC rails 2, i.e. all areas, are surrounded by an electrically insulating overmolding 5, which is only not present in areas where the DC rails 2 are to be electrically contacted.

[0026] The temperature sensor 31 remains on the top side of the circuit board 3. An existing current sensor 32 can also remain there. Likewise, the signal connection to the circuit board 9 remains in the area of ​​the inverter modules. Furthermore, electrical contacts in the form of, for example, contact springs 33 are provided on the circuit board 3, which serve as DC taps to the top side of the circuit board 3. The contacts 33 can be arranged on an outer area of ​​the circuit board 3 or can penetrate through a recess in the circuit board 3 to its underside and contact the DC rails 2 there.

[0027] Furthermore, the X and Y capacitors 8 are arranged on the underside of the circuit board 3, i.e., opposite the sensors 31, 32 arranged on the top side of the circuit board 3, across the circuit board 3. The X and Y capacitors 8 are electrically connected to both the DC rails 2 and the GND terminals 30 via conductor tracks integrated into the circuit board 3.

[0028] As in the prior art, a carrier 4 is provided, which is applied over the cores 1 as a type of housing. It is made of an electrically insulating material and formed in such a way that it also insulates the area of ​​the passages 11, but leaves a passage for the DC busbars 2. It is connected to the overmolding of the DC busbars 5 via fastening elements 40.

[0029] In order to, among other things, mitigate shocks and thus reduce or avoid damage to the DC EMC input filter area, a buffer element 6 can also be provided, which is arranged between the carrier 4 and the third part of the DC rails 2.

[0030] The EMC input filter is advantageously used as part of an electronic module used to operate an electric drive of a vehicle, in particular an electric vehicle and / or a hybrid vehicle, and / or electrified axles. The electronic module comprises an inverter arrangement with a DC / AC inverter that converts the DC input current filtered by the EMC input filter into an AC output current. It can also comprise or be part of an AC / DC rectifier, a DC / DC converter, a transformer, and / or another electrical converter or a part of such a converter. In particular, the electronic module serves to supply current to an electric machine, for example, an electric motor and / or a generator.A DC / AC inverter is preferably used to generate a multi-phase alternating current from a direct current generated by means of a DC voltage from an energy source, such as a battery or accumulator. List of reference symbols 1 core input filter 11 passage cores 2, 2.1 DC rails 3 circuit board 30 GND connections 31 Temperature sensor 32 current sensor 33 Contacting 3 and 22 4 carrier cores 40 fasteners 5 Overmolding of DC rails 6 Buffer element 7 DC input jacks 8 X or Y capacitor 9 Circuit board in the area of ​​the inverter modules

Claims

[1] EMC input filter arrangement of a power electronics application in a vehicle, comprising two adjacently arranged magnetic cores (1), each having a top side and a bottom side and a central passage (11), wherein the passages (11) are arranged parallel to one another, - a holder (41) made of electrically non-conductive material, which forms a surface for receiving the underside of the magnetic cores (1), - DC busbars (2) comprising DC plus and DC minus busbars, which are formed in several parts in such a way, - that a first part is guided to the underside of the first magnetic core (1), and that a second part is guided away from the underside of the second magnetic core (1), and - that a third part is formed as a substantially U-shaped plug-in component such that two mutually parallel legs are formed, one of which is guided from the top side into a central passage (11) of the associated magnetic core (1) to its underside and is electrically contacted with the associated first or second part of the DC plus and DC minus busbars (2), and wherein the parallel legs are connected to one another on their end regions facing away from the magnetic cores (1) via a third leg which is guided parallel to the surface of the holder (41), and - a printed circuit board (3) arranged above the at least one magnetic core (1) and extending over at least the surface of the two magnetic cores (1), the underside of which is parallel to the surface of the holder (41), wherein the printed circuit board (3) and the DC busbars are in electrical contact with one another via conductor tracks (2). [2] EMC input filter arrangement according to claim 1, wherein screwing points (30) connectable to GND are provided at outer end regions of the printed circuit board (3), and wherein at least one X-capacitor (8) and at least one Y-capacitor (8) are arranged on an underside of the printed circuit board (3) facing the holder (41), of which one connection is connected to the associated DC busbar (2) and the other connection is connected via an associated connection point to GND by means of conductor tracks in the printed circuit board (3). [3] EMC input filter arrangement according to claim 1 or 2, wherein at least one current sensor for tapping current on the DC negative busbar is arranged on an upper side of the circuit board (3) opposite the underside, and wherein contact springs (33) introduced into the circuit board (3) are arranged at the outer end regions of the circuit board (3) in such a way that they contact the associated DC busbars (2). [4] EMC input filter arrangement according to one of the preceding claims, wherein the first, the second and the third part of the DC busbars (2) are at least partially surrounded by an electrically insulating overmolding (5). [5] EMC input filter arrangement according to one of the preceding claims, further comprising an electrically insulating carrier (4) in which the cores (1) are received. [6] EMC input filter arrangement according to one of the preceding claims, wherein the second part of the DC busbars (2) is a partial region of the second leg of the substantially U-shaped plug-in component. [7] EMC input filter arrangement according to one of the preceding claims, wherein at least one buffer element (6) for mechanical buffering is provided between the electrically insulating carrier (4) and the third part of the DC busbars (2), and / or wherein the printed circuit board (3) has at least one temperature sensor on its upper side and X and Y capacitors on its underside. [8] Electronic module comprising the EMC input filter arrangement according to one of claims 1 to 7, and an inverter arrangement which is designed to convert a DC input current filtered by the EMC input filter into an AC output current. [9] Electric drive of a vehicle, comprising the electronic module according to claim 8 for controlling the electric drive. [10] Vehicle comprising an electric drive according to claim 9.

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