DE102021110988A1 - EMC filter device with a shielding cover; and power electronics module - Google Patents

Abstract

The invention relates to an EMC filter device (1) for power electronics of an electrical machine, having an electrical conductor structure (2), at least one capacitance (3a, 3b) coupled to the conductor structure (2) and at least one capacitance interacting with the conductor structure (2). Inductance (4a, 4b), wherein the conductor structure (2) has at least two individual conductive layers (6a, 6b) insulated from one another, and wherein there is also a cover (27) that at least partially shields the conductor structure (2) from the environment, which cover (27) is provided with an EMC seal (28). The invention also relates to a power electronics module (20) with this EMC filter device (1).

Description

The invention relates to an EMC filter device for power electronics of an electrical machine, preferably an electrical machine used as a drive unit in a motor vehicle.

The aim is to provide a filter device that functions as reliably as possible in the sense of a mains filter for use in power electronics, which on the one hand has a structure that is as compact as possible, in particular flat, and on the other hand is equipped with as few interfaces/contacts as possible.

According to the invention, this is achieved by the subject matter of claim 1 . Accordingly, an EMC filter device is provided for power electronics of an electrical machine, which has an electrical conductor structure, at least one capacitance coupled to the conductor structure, and at least one inductance interacting with the conductor structure, the conductor structure having at least two individual conductive layers insulated from one another, and further there is a cover that at least partially shields the conductor structure from the environment, which cover is provided with an EMC seal. In particular, an EMC seal is a seal that is impervious to electrical interference signals. The conductor structure is thus designed, for example, as a laminated busbar or high-current printed circuit board.

The abbreviation "EMC" used herein stands for Electromagnetic Compatibility". Accordingly, an EMC filter device is a filter device that ensures or improves the electromagnetic compatibility of a device, for example a power electronics module, to which the filter device is coupled.

Due to its compact design, this EMC filter device according to the invention can be integrated more easily into existing installation spaces, for example in a housing of an inverter unit, or the inverter unit can be designed to be more compact overall. Such a cover results in a shielding unit that is easy to assemble and produce, which enables the individual components of the filter device to be shielded over a large area. As a result, the filter device becomes significantly more reliable in its function.

Further advantageous embodiments are claimed with the dependent claims and explained in more detail below.

Accordingly, it is also advantageous if the cover has a plate-shaped cover and a side wall attached to the cover, which side wall surrounds the at least one capacitance and the at least one inductance. As a result, the cover is composed of as few individual parts as possible.

The side wall is preferably made of the same material as the cover, but in other versions it can also be made of a different material than the cover. Accordingly, depending on the area of use, it is possible to manufacture the cover efficiently.

In this respect, it is advantageous if the cover has a side wall and the EMC seal is inserted between an end face of the side wall facing the conductor structure and the conductor structure. As a result, the EMC seal can be cleverly clamped between the conductor structure and the side wall, so that further precautions for accommodating the EMC seal can be omitted. In this regard, it is particularly advantageous if the EMC seal is glued to the end face.

If the EMC seal is designed as a sealing strip following/running around the circumference of the side wall or if the EMC seal has such a sealing strip, the structure of the seal is also kept as simple as possible.

If the cover shields the at least one capacitance coupled to the conductor structure from the environment, the shielding of the components of the filter device is further improved.

In this regard, it is therefore also expedient if a current sensor attached to the conductor structure and/or two connections are/is shielded from the environment by the cover.

If an insulating film is arranged between the individual conductive layers of the conductor structure, the conductor structure is constructed as compactly as possible.

In this regard, it is also expedient if the conductor structure is surrounded/encased in its entirety on the outside/on the outside by an insulating film.

It is also advantageous if the at least one inductor has a core (preferably designed as a toroidal core) and the conductor structure is inserted/projects through this core. This also results in an arrangement that is as compact as possible.

Furthermore, the invention relates to a power electronics module for an electrical machine, with a capacitor arrangement and an EMC filter device according to the invention, which is electrically connected to the capacitor arrangement, according to at least one of the previously described embodiments.

Furthermore, with regard to the power electronics module, it is advantageous if the conductor structure bears directly or indirectly on a region of the capacitor arrangement which is fixed to the housing. This further improves the cooling accordingly.

It has proven to be particularly advantageous if the area fixed to the housing is arranged on an underside of the conductor structure and the cover is arranged on an upper side of the conductor structure. This results in a design that saves as much space as possible and an arrangement of the filter device in the inverter unit that saves space.

Furthermore, it is expedient if a plurality of capacitors in the capacitor arrangement are also fastened on an upper side of the conductor structure. In this case, the conductor structure preferably has a corresponding extension, on which the individual capacitors are arranged in series and/or parallel to one another. As a result, the conductor structure is used even more skilfully for a compact construction of the inverter unit.

Furthermore, it is advantageous if a current input of the power electronics module is formed directly by the conductor structure and a current output of the power electronics module is formed by the capacitor arrangement.

In other words, according to the invention, an EMC filter (EMC filter device) and the corresponding DC connections are shielded in an inverter (inverter unit). The EMC filter is constructed using a laminated bus bar (conductor structure). The bus bar includes at least two electrically conductive layers that are insulated from one another. An EMC shielding wall (side wall) is integrated in an inverter housing in particular and is provided with an EMC seal. The EMC seal can be designed as a sealing strip.

The invention will now be explained in more detail below with reference to figures.

• 1 eine Draufsicht auf eine erfindungsgemäße EMV-Filtervorrichtung nach einem bevorzugten Ausführungsbeispiel als Bestandteil einer Invertereinheit, sowie
• 2 eine Querschnittsdarstellung der EMV-Filtervorrichtung nach 1, sodass eine zwischen einer Leiterstruktur und einem gehäusefesten Bereich angeordnete, wärmeleitende Schicht und zwei zur Abschirmung dienende Seitenwände zu erkennen sind.

Show it:

• 1 a plan view of an inventive EMC filter device according to a preferred embodiment as part of an inverter unit, and
• 2 a cross-sectional view of the EMC filter device 1 , so that a heat-conducting layer arranged between a conductor structure and an area fixed to the housing and two side walls serving for shielding can be seen.

The figures are only of a schematic nature and serve exclusively for understanding the invention. The same elements are provided with the same reference numbers.

With 1 an EMC filter device 1 according to the invention can be clearly seen. In this embodiment, the EMC filter device 1 is implemented as an independent module, but in further embodiments according to the invention it is also directly embodied as a component of a power electronics module 20 / an inverter unit 11 . The inverter unit 11 then in turn forms part of the in 1 generally indicated power electronics module 20 / power electronics for an electrical machine. The EMC filter device 1 is thus used in power electronics of an electrical machine of a motor vehicle, which is preferably designed as a drive machine.

The EMC filter device 1 has, as well as in the 2 and 3 to see in more detail, a laminated conductor structure 2, which is implemented as a laminated busbar 5 here. In further versions, the conductor structure 2 is also implemented as a printed circuit board, namely as a high-current printed circuit board. The conductor structure 2, alternatively also referred to as a busbar or busbar, has several 2 indicated, mutually insulated conductive layers 6a, 6b. The conductive layers 6a, 6b lie flat/coplanar on one another and form the conductor structure 2/busbar 5 as a whole. Between the conductive layers 6a, 6b, as also in 2 indicated, an insulating film 7 is interposed, which is used directly to insulate the two conductive layers 6a, 6b relative to one another. The conductor structure 2, ie the entirety of conductive layers 6a, 6b, is also sealed from its outside by such an insulating film 7. In further versions, the conductor structure 2 also consists of more than two, for example three or four, conductive layers 6a, 6b.

The conductor structure 2 has an essentially plate-shaped structure. According to the design as an EMC filter device 1, the conductor structure 2 has two inductances 4a, 4b. A first inductor 4a has a first core 8a, and a second inductor 4b has a second core 8b. Each core 8a, 8b is designed as a ring core/ring-shaped. A section of the conductor structure 2 extends centrally through these cores 8a, 8b arranged next to one another.

Two connections 10a, 10b are implemented on the conductor structure 2 towards a common side of the two inductances 4a, 4b and form a current input during operation. The two terminals 10a, 10b are connected to a power supply 9, preferably a high-voltage battery, during operation, as also indicated. The two connections 10a, 10b form not only a current input of the EMC filter device 1, but also a current input 16 of the inverter unit 11 and the power electronics module 20.

Furthermore, two capacitances 3a, 3b in the form of capacitors are placed/applied to the conductor structure 2. The two capacitances 3a, 3b thus form two first electronic components 21 which are accommodated/attached to the conductor structure 2. The respective first electronic component 21 is preferably cohesively fixed on the conductor structure 2, for example soldered or welded on.

Another second electronic component 22, which is accommodated/attached to the conductor structure 2, is implemented as a current sensor 24 and is therefore used to detect an electric current ( 1 and 2 ). The current sensor 24 is attached to the conductor structure 2 via a weld point 36 .

Furthermore, a third electronic component 23 in the form of a discharge resistor 25 is accommodated/attached to the conductor structure 2 ( 1 ). The third electronic component 23 is also preferably fixed to the conductor structure 2 in a materially bonded manner.

As an alternative to the form-fit connection of the respective component 21, 22, 23, another connection of the respective component 21, 22, 23 is also provided in further embodiments, for example force-fit via fastening means such as screws.

In 1 also shows that the conductor structure 2 is connected to a capacitor arrangement 12 of the inverter unit 11 . A corresponding connection takes place, for example, in the area of a dividing line 33 . In a further preferred exemplary embodiment, however, the conductor structure 2 is also formed in one piece with a rail 35 of the capacitor arrangement 12 , so that a plurality of capacitors 26 of the capacitor arrangement 12 are also arranged on the conductor structure 2 . The EMC filter device 1 is then a direct component of an inverter unit 11 having the capacitor arrangement 12. The capacitors 26 are implemented as discrete capacitors 26 and are arranged in two parallel rows, for example.

The inverter unit 11 has a housing 13, which is also referred to as the inverter housing. This housing 13 encloses both the capacitor arrangement 12 and the EMC filter device 1 with the conductor structure 2. However, it should again be pointed out that in further embodiments the EMC filter device 1 has its own housing, which is then firmly attached to the housing 13 and can therefore be referred to as the area 14 of the housing 13 which is fixed to the housing.

In 2 In this respect it can be seen that the conductor structure 2 with its electronic components 21, 22, 23 and the inductances 4a, 4b is placed on a region 14 of the housing 13 which is fixed to the housing. The area 14 fixed to the housing is implemented here directly as a plate-shaped area of the housing 13 . In further embodiments, the area 14 fixed to the housing is also designed in a different way as a heat sink, which is further connected to the housing 13 .

With 2 It can also be seen that there is a cover 29 which, together with the area 14 fixed to the housing, accommodates the EMC filter device 1 . When viewed in the plane of the drawing, the conductor structure 2 rests with its underside 19 (here indirectly) on the area 14 fixed to the housing. The electronic components 21 , 22 , 23 are attached to their upper side 18 .

Furthermore, the two cores 8a, 8b are connected to the area 14 fixed to the housing via an adhesive connection 34. It can also be seen here that the two connections 10a, 10b are implemented as so-called pins and protrude at least through the cover 29.

It should also be pointed out that in a further preferred embodiment a cover 27 forming a shield is also formed by the cover 29 . The cover 27 is formed by the cover 29 and a side wall 30 fastened to the cover 29 . The cover 29 and side wall 30 thus form a shielding hood which is placed on the conductor structure 2 and is supported on the latter via the side walls 30 .

In this regard, in 2 It can also be seen that an EMC seal 28 is interposed between an end face 31 of the side walls 30 and the conductor structure 2/the top side 18 of the conductor structure 2. This EMC seal 28 has a sealing strip 32 or is implemented as such a sealing strip 32 . The EMC seal 28 extends over the entire circumference of the side wall 30 and thus seals off an interior of the cover 27 from the environment.

The side walls 30 are formed separately from the cover 29 and are attached/attached thereto. For example, the side wall 30 is welded to the cover 29 or attached in a non-positive manner, for example by means of fastening means. In further embodiments, however, the side walls 30 are also designed as a one-piece material component of the cover 29 .

Out of 2 It can also be seen that a thermally conductive layer 15, which is implemented as a “gap pad” in a preferred variant, is used between the conductor structure 2 and the area 14 fixed to the housing. The layer 15 thus formed as a mat thus serves to dissipate waste heat from the conductor structure 2 in the direction of the area 14 fixed to the housing. The layer 15 is elastically deformable and inserted between the conductor structure 2 and the area 14 fixed to the housing in a compressed manner. The layer 15 consists of some thermally conductive material, such as a thermally conductive filled composite. In further embodiments, the layer 15 is alternatively implemented as a gel layer or as a casting compound.

While the connections 10a, 10b, as already mentioned, form the overall current input 16 of the inverter unit 11/the power electronics module 20, an output of the capacitor arrangement 12 typically forms an in 1 schematically indicated current output 17 of the inverter unit 11 / of the power electronics module 20.

In other words, according to the invention, partition walls (side walls 30) are integrated or mounted (e.g. screws, welding, etc.) in an inverter cover (cover 27).

In a variant embodiment, these partitions are made of the same material as the inverter cover. In another variant, these partitions consist of a special EMC shielding material.

One or more EMC seal(s) 28 is installed between the partition and the laminated busbar (busbar 5). This EMC seal 28 can be routed as a sealing tape 32 around the EMC filter and the DC connections. The EMC sealing tape can be glued to the partition.

The laminated bus bar consists of two or more coplanar conductive plates (e.g. copper plates; also referred to as conductive layers 6a, 6b) with the intermediate and outer insulating foils 7 laminated.

The passive components (e.g. capacitors) can be soldered directly onto the laminated busbar. Current sensor 24 (DC side) and discharge resistor 25 can be connected directly to the laminated busbar (e.g. by means of laser welding).

In one embodiment variant, a DC link capacitor can be connected as a parallel connection of discrete capacitors (capacitors 3a, 3b) via the laminated busbar.

The bus bar is placed close to the housing 13 and thermally connected to the inverter housing 13 via thermally conductive materials (e.g. gap pad).

The cores 8a, 8b are introduced into the inverter housing 13 and fixed with an adhesive (e.g. with epoxy adhesive) or with a casting material and thermally connected to the inverter housing 13.

An EMC shielding wall (side wall 30) is integrated into the inverter cover (cover 27) and provided with an EMC seal 28. After the cover 29 has been closed, the EMC filter and the DC input connector are protected from electromagnetic radiation coupling.

reference list

1

EMC filter device

2

ladder structure

3a

first capacity

3b

second capacity

4a

first inductance

4b

second inductance

5

busbar

6a

first conductive layer

6b

second conductive layer

7

insulation film

8a

first core

8b

second core

9

power supply

10a

first connection

10b

second connection

11

inverter unit

12

capacitor arrangement

13

Housing

14

housing-fixed area

15

mat

16

power input

17

current output

18

top

19

bottom

20

power electronics module

21

first electronic component

22

second electronic component

23

third electronic component

24

current sensor

25

discharge resistance

26

capacitor

27

cover

28

EMC gasket

29

lid

30

Side wall

31

face

32

sealing tape

33

parting line

34

adhesive connection

35

rail

36

weld

Claims (10)

EMC filter device (1) for power electronics of an electrical machine, having an electrical conductor structure (2), at least one capacitance (3a, 3b) coupled to the conductor structure (2) and at least one inductance (4a) interacting with the conductor structure (2), 4b), wherein the conductor structure (2) has at least two individual conductive layers (6a, 6b) insulated from one another, and wherein there is also a cover (27) that at least partially shields the conductor structure (2) from the environment, which cover (27) with an EMC seal (28) is provided. EMC filter device (1) after claim 1 , characterized in that the cover (27) has a plate-shaped cover (29) and a side wall (30) attached to the cover (29), which side wall (30) has the at least one capacitance (3a, 3b) and the at least one inductance (4a, 4b) surrounds. EMC filter device (1) after claim 1 or 2 , characterized in that the cover (27) has a side wall (30) and the EMC seal (28) between a conductor structure (2) facing end face (31) of the side wall (30) and the conductor structure (2) is used. EMC filter device (1) according to one of Claims 1 until 3 , characterized in that the EMC seal (28) has a circumference of the side wall (30) following the sealing band (32). EMC filter device (1) according to one of Claims 1 until 4 , characterized in that the at least one capacitor (3a, 3b) coupled to the conductor structure (2) is shielded from the environment by the cover (27). EMC filter device (1) according to one of Claims 1 until 5 , characterized in that a current sensor (24) fastened to the conductor structure (2) and/or two connections (10a, 10b) are/is shielded from the environment by the cover (27). Power electronics module (20) for an electrical machine, with a capacitor arrangement (12) and with the capacitor arrangement (12) electrically connected EMC filter device (1) according to one of Claims 1 until 6 . Power electronics module (20) after claim 7 , characterized in that the conductor structure (2) bears directly or indirectly on a housing-fixed area (14) of the capacitor arrangement (12). Power electronics module (20) after claim 8 , characterized in that the housing-fixed area (14) is arranged on an underside (19) of the conductor structure (2) and the cover (27) is arranged on an upper side (18) of the conductor structure (2). Power electronics module (20) according to one of Claims 7 until 9 , characterized in that a current input (16) of the electronic power module (20) is formed directly by the conductor structure (2) and a current output (17) of the electronic power module (20) is formed by the capacitor arrangement (12).

Images