DE102018206291A1 - EMC filters - Google Patents

Abstract

An EMC filter (1) comprising a plurality of filter components, comprising at least one common mode choke (10), a DC link capacitor (21), a Y capacitor (20), and an X capacitor (40), the EMC filter thus formed in that each filter component is positionable to exert a damping effect on the EMC filter (1) in addition to its respective major function.

Description

The present invention relates to an EMC filter.

EMC filters (EMC = Electromagnetic Compatibility) are used in power electronics in vehicles to ensure the most trouble-free on-board electrical system. The EMC filter can be used both on the DC (DC) side and on the AC (AC = AC) side of the power electronics. In the case of an inverter that converts the DC energy of the battery to the AC energy at the E-machine, the EMC filter is installed at the DC high-voltage interface to reduce the spread of electromagnetic interference towards the battery.

Previously used EMC filters have a non-optimal utilization of the installation space, since the filter components are not optimally introduced into the space and thereby the damping effect of the filter is reduced.

Therefore, it is an object of this invention to provide an improved EMC filter with improved utilization of packaging space. This object is achieved by the features of the independent claim. Advantageous embodiments are the subject of the dependent claims.

Provided is an EMC filter comprising a plurality of filter components comprising at least a common mode choke, a DC link capacitor, a Y capacitor and an X capacitor, the EMC filter being formed such that each filter component is positionable to additionally to their respective main function exerts a dampening effect on the EMC filter.

In one embodiment, the EMC filter further comprises a housing in which at least the DC link capacitor is arranged, wherein at least the common mode choke and the Y capacitor are also arranged in the housing. By placing multiple filter components in a housing, space can be saved.

In one embodiment, a mounting is provided on the housing, which serves as a throttle attachment for fixing the common mode choke and as a ground connection of the Y capacitor at the same time. By attaching the throttle to the housing so that the same attachment serves as a ground connection for the Y-capacitor, space is saved.

In one embodiment, the throttle attachment is formed such that the X-capacitor can be fastened on the side of a DC power plug. Thus, line lengths are shortened and noise is reduced.

In one embodiment, the Y capacitor is disposed adjacent to semiconductor components disposed on a printed circuit board. Thus, the anti-interference effect of the Y-capacitor can be better utilized.

In one embodiment, a DC current sensor is provided as an additional filter component disposed between the common mode choke and the X capacitor. Thus, the parasitic effect can be used and at the same time the damping effect can be enhanced.

In one embodiment, a push-pull throttle is further provided as an additional filter component, which is positioned and dimensioned depending on a required for the intended application damping between the common mode choke and the X-capacitor.

In one embodiment, a separate cooling unit is provided for each of the filter components. Thus, interfaces can be reduced and it can be individually tailored to the cooling requirements of the component.

In one embodiment, the EMC filter is part of a drive inverter for use in the automotive sector.

Further features and advantages of the invention will become apparent from the following description of embodiments of the invention, with reference to the figures of the drawing, the inventive details shows, and from the claims. The individual features can be realized individually for themselves or for several in any combination in a variant of the invention.

• 1 zeigt eine Ansicht eines Wechselrichters mit EMV-Filter gemäß einer Ausführung der vorliegenden Erfindung.
• 2 zeigt eine Ansicht einer Befestigung der Gleichtaktdrossel gemäß einer Ausführung der vorliegenden Erfindung.
• 3 zeigt eine Ansicht einer Verbindung an der Gleichtaktdrossel für den X-Kondensator gemäß einer Ausführung der vorliegenden Erfindung.
• 4 zeigt eine andere Ansicht der in 3 gezeigten Verbindung an der Gleichtaktdrossel für den X-Kondensator gemäß einer Ausführung der vorliegenden Erfindung.
• 5 zeigt eine Ansicht einer Anordnung einer weiteren Komponente gemäß einer Ausführung der vorliegenden Erfindung.

Preferred embodiments of the invention are explained below with reference to the accompanying drawings.

• 1 shows a view of an inverter with EMC filter according to an embodiment of the present invention.
• 2 shows a view of a mounting of the common mode choke according to an embodiment of the present invention.
• 3 shows a view of a connection to the common mode choke for the X-capacitor according to an embodiment of the present invention.
• 4 shows another view of the in 3 shown connection to the common mode choke for the X-capacitor according to an embodiment of the present invention.
• 5 shows a view of an arrangement of another component according to an embodiment of the present invention.

In the following description of the figures, the same elements or functions are provided with the same reference numerals.

The core of the invention is to achieve a reduction of the installation space for the arrangement of filter components in EMC filters and thus to optimize the filter damping.

1 to 5 show different views of the inventive concept of the arrangement of filter components of an EMC filter 1 comprising a throttle 10 , which is usually designed as a common mode choke, a component 20 comprising a DC link capacitor 21 and a Y-capacitor 22 as well as an X-capacitor 40 , Further, semiconductor components 30 as well as a throttle attachment 11 and interfaces for attachment 23 and for electrical contact with a DC power connector 3 intended. It can also be seen that the connection to the DC power connector 3 near the choke or common mode choke 10 and the X-capacitor 40 is arranged. Such an EMC filter 1 is advantageously used in drive inverters, which are used in the automotive sector.

2 shows a section of a bottom view of in 1 shown view. Here it can be seen that due to the arrangement according to the invention, the throttle 10 the housing of the DC link capacitor 21 can share. The Y-capacitor 22 is located in the same housing as the DC link capacitor 21 , The attachment 23 , which can be designed as a screw, can simultaneously for the attachment of the throttle 10 and the ground connection of the Y-capacitor 22 be used. In addition, the throttle fitting 11 be formed such that the X-capacitor 40 on the side of the DC power connector 3 can be attached. This is in 3 and 4 illustrated from different angles. More specifically, the individual electrical connection locations may be formed spaced apart from each other so that the X-capacitor 40 there is room in between, as in 4 to see.

The core of the invention is that different filter components 10 . 20 . 40 Integration into an optimal position within a drive inverter to accomplish both its primary task and to provide enhanced (filter) damping while optimally utilizing space.

The most important filter components in such a drive inverter are the common mode choke 10 , the Y capacitors 20 and the X capacitors 40 ,

The common mode choke 10 or current-compensated filter choke or short CMC (English common mode choke) is used to attenuate spurious emissions. X and Y capacitors are used as suppression capacitors, eg for removing leakage currents.

By positioning a Y-capacitor 22 close to the semiconductor components 30 which is usually on a circuit board 7 are arranged and represent the most important source of interference in terms of electromagnetic compatibility, the suppression effect can be better used. In principle, the disturbance must be removed as close as possible to the source in order to avoid further processing. The presented, integrated concept makes the path between Y-capacitor 22 and semiconductors 30 kept as short as possible. Thus, the inductance L between power module or semiconductor 30 and Y-capacitor 22 minimized, ensuring a small impedance for the path. Also, the space can be used better because interfaces or longer connecting lines, which in turn must be checked for EMC compatibility, at least largely omitted.

By the distribution of the filter components 10 . 20 . 40 such that they can achieve a better damping effect, space for other components is also provided, which can also contribute to the damping of the disturbance in addition to their main function. An example of this is the DC current sensor 50 , as in 5 shown. By placing the DC current sensor 50 between the common mode choke 10 and the X-capacitor 40 the parasitic effect is used and the damping is increased. However, the X-capacitor can 40 in this example no longer the throttle attachment 11 the common mode choke 10 share how 3 and 4 but must be behind the DC current sensor 50 in the direction of DC plug 3 to be placed.

An additional advantage of the distributed filter components 10 . 20 . 40 is it that for the filter components 10 . 20 . 40 Depending on their respective losses and their thermal behavior, various cooling options can be implemented via corresponding cooling units, whereby interfaces are reduced. The cooling units can be individually tuned to the component to be cooled, ie both in their shape and their cooling capacity.

Another way to improve the EMC filter 1 is to position additional filter components such as push-pull throttles such that a required or required for the particular application damping can be achieved. This is also possible because of the positioning of the other filter components 10 . 20 . 40 Space is released at a suitable location.

Due to the EMC filter concept of the drive inverter, a reduction of the installation space for the filtering is achieved. Furthermore, optimum utilization of the filter components is ensured so that an additional damping effect is ensured via the filter components.

The exact positioning of each individual component depends on the particular application and the components used.

LIST OF REFERENCE NUMBERS

1

EMC filters

10

Common mode choke

11

Damper fastening

23

screw point

3

Connection DC power connector

20

DC link capacitor with Y capacitor

22

Y-capacitor

30

Semiconductor components

40

X capacitor

50

DC current sensor

Claims (9)

An EMC filter (1) comprising a plurality of filter components, comprising at least one common mode choke (10), a DC link capacitor (21), a Y capacitor (20), and an X capacitor (40), the EMC filter thus formed in that each filter component is positionable to exert a damping effect on the EMC filter (1) in addition to its respective major function. EMC filter (1) after Claim 1 , further comprising a housing, in which at least the intermediate circuit capacitor (21) is arranged, wherein at least the common mode choke (10) and the Y capacitor (22) are also arranged in the housing. EMC filter (1) after Claim 1 or 2 in which a fastening (23) is provided on the housing, which at the same time serves as a throttle attachment (11) for fastening the common mode choke (10) and as a ground connection of the Y capacitor (22). EMC filter (1) after Claim 3 , wherein the throttle attachment (11) is formed such that the X-capacitor (40) on the side of a DC power connector (3) can be fastened. EMC filter (1) according to one of the preceding claims, wherein the Y-capacitor (21) adjacent to arranged on a printed circuit board (7) semiconductor components (30) is arranged. An EMC filter (1) according to any one of the preceding claims, further comprising a DC current sensor (50) as an additional filter component disposed between the common mode choke (10) and the X capacitor (40). An EMC filter (1) according to any one of the preceding claims, further comprising a push-pull choke as an additional filter component positioned and dimensioned between a common mode choke (10) and the X-capacitor (40) depending on a damping required for the intended application , EMC filter (1) according to one of the preceding claims, wherein a separate cooling unit is provided for each of the filter components. EMC filter (1) according to one of the preceding claims, wherein the EMC filter (1) is part of a drive inverter for use in the automotive sector.

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