EMV Filters

Abstract

The invention relates to an EMC filter (1) having a plurality of filter components, the filter components comprising at least a common mode choke (10), an intermediate circuit capacitor (21), a Y capacitor (20) and an X capacitor (40), wherein the EMC filter is formed such that each filter component can be positioned in such a way that, in addition to its respective main function, the filter component also exerts a damping effect on the EMC filter (1).

Description

Technical Field

[0001] The invention relates to an EMC filter. Background Art

[0002] EMC filters (EMC = electromagnetic compatibility) are used in power electronics in vehicles to ensure that the onboard electrical system is as interference-free as possible. EMC filters can be used both on the DC (DC = direct current) side of the power electronics and on the AC (AC = alternating current) side. In the case of inverters that convert the DC energy of the battery into AC energy for the electric motor, EMC filters are installed on the DC high-voltage connection in order to reduce the propagation of electromagnetic interference in the direction of the battery.

[0003] The EMC filters used hitherto do not make optimal use of the installation space, since the filter components are not optimally introduced into the installation space and the damping effect of the filter is thereby reduced. Summary of the invention

[0004] Therefore, it is an object of the present invention to provide an improved EMC filter which has an improved utilization of the installation space. This object is achieved according to the present invention by the following EMC filter. The present invention also has an advantageous embodiment.

[0005] An EMC filter is provided, which comprises a plurality of filter components, which comprise at least a common mode choke, an intermediate circuit capacitor, a Y capacitor and an X capacitor, wherein the EMC filter is formed so that each filter component can be positioned in such a way that it exerts a damping effect on the EMC filter in addition to its respective main function.

[0006] Furthermore, in one embodiment, the EMC filter has a housing in which at least an intermediate circuit capacitor is arranged, wherein at least a common mode choke and a Y capacitor are also arranged in the housing. By placing a plurality of filter components in the housing, space can be saved.

[0007] In one embodiment, a fastening portion is provided on the housing, which is used as a choke fastening portion for fastening the common mode choke and as a grounding portion of the Y capacitor. By fastening the choke to the housing, the fastening portion is also used as a grounding portion of the Y capacitor, so as to save space.

[0008] In one embodiment, the choke fastening portion is formed in such a way that the X capacitor can be fastened on the side of the DC current plug. Thus, the line length is shortened and interference is reduced.

[0009] In one embodiment, the Y capacitor is arranged adjacent to the semiconductor component arranged on the circuit board. Therefore, the interference elimination effect of the Y capacitor can be better utilized.

[0010] In one embodiment, a DC current sensor is provided as an additional filter component, which is arranged between the common mode choke and the X capacitor. Thus, parasitic effects can be used and at the same time the damping effect is enhanced.

[0011] In one embodiment, a push-pull choke is also provided as an additional filter component, which is positioned between the common mode choke and the X capacitor and dimensioned depending on the damping required for the intended application.

[0012] In one embodiment, a separate cooling unit is provided for each filter component, thereby reducing interfaces and allowing the cooling requirements of the components to be considered individually.

[0013] In one embodiment, the EMC filter is a component of a drive inverter for use in the automotive sector.

[0014] Further features and advantages of the present invention are apparent from the following description of an exemplary embodiment of the present invention in conjunction with the accompanying drawings which show details according to the present invention. In variants of the present invention, the individual features can be realized individually by themselves or in any desired combination. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0016] Figure 1 A view showing an inverter with an EMC filter according to an embodiment of the present invention;

[0017] Figure 2 A view showing a fastening portion of a common mode choke coil according to an embodiment of the present invention;

[0018] Figure 3 A diagram showing the connection of an X-capacitor to a common mode choke according to an embodiment of the present invention;

[0019] Figure 4 Another view showing the connection on a common mode choke for an X capacitor according to an embodiment of the present invention;

[0020] Figure 5 A view showing an arrangement of further components according to an embodiment of the present invention;

[0021] In the following detailed description, the same elements or functions have the same reference numerals. DETAILED DESCRIPTION

[0022] The core of the invention is to achieve a reduction in the installation space for arranging filter components in an EMC filter and thereby optimize the filter damping.

[0023] Figures 1 to 5 Different views of the concept according to the invention showing the arrangement of the filter components of an EMC filter 1, which comprises a choke 10 which is usually designed as a common mode choke and comprises a component 20 with an intermediate circuit capacitor 21 and a Y capacitor 22 as well as an X capacitor 40. In addition, a semiconductor component 30 is provided as well as a choke fastening 11 and an interface 23 for fastening and an interface for electrical contacting of a DC current plug 3. It can also be seen that the connection to the DC current plug 3 is arranged in the vicinity of the choke or common mode choke 10 and the X capacitor 40. Such an EMC filter 1 is advantageously used in drive inverters used in the automotive sector.

[0024] Figure 2 Shows Figure 1 Detail of the bottom view of the view shown in . It can be seen here that, due to the arrangement according to the invention, the choke 10 can share the housing of the intermediate circuit capacitor 21. The Y capacitor 22 is located in the same housing as the intermediate circuit capacitor 21. The fastening 23, which can be implemented as a screw connection, can be used simultaneously to fasten the choke 10 and the grounding of the Y capacitor. In addition, the choke fastening 11 can be formed in such a way that the X capacitor 40 can be mounted on the side of the DC current plug 3. This is particularly useful in Figure 3 and 4 In more detail, the electrical connection locations may be formed spaced apart from each other so that the X capacitor 40 is located in the empty space between them, such as Figure 4 shown.

[0025] The core of the invention is that the various filter components 10 , 20 , 40 are optimally positioned within the drive inverter by integration in order not only to fulfill their primary task but also to provide improved (filter) damping while still making optimal use of the installation space.

[0026] The most important filter components in such a drive inverter are the common mode choke 10 , the Y capacitor 20 and the X capacitor 40 .

[0027] The common mode choke 10 or current-compensated filter choke or CMC for short (Common Mode Choke in English) serves to damp interference emissions. The X and Y capacitors serve as interference suppression capacitors, for example, to eliminate leakage currents.

[0028] By positioning the Y capacitor 22 near the semiconductor components 30, which are usually arranged on the circuit board 7 and are the most important interference sources in terms of electromagnetic compatibility, the interference damping effect of the Y capacitor can be better utilized. In principle, the interference must be eliminated as close to the source as possible to avoid further propagation. Through the proposed integrated concept, the path between the Y capacitor 22 and the semiconductor 30 is as short as possible. Therefore, the inductance L between the power module or the semiconductor 30 and the Y capacitor 22 is minimized, thereby ensuring that the impedance for the path is small. In addition, the structural space can also be better utilized, because at least to a large extent, interfaces or long connecting lines that must be checked again for EMC are eliminated.

[0029] By distributing the filter components 10, 20, 40 so that they can achieve a better damping effect, construction space is provided for other components that, in addition to their main function, can also contribute to the damping of interferences. Examples of this are Figure 5 The DC current sensor 50 shown. By placing the DC current sensor 50 between the common mode choke 10 and the X capacitor 40, the parasitic effect is utilized and the damping is enhanced. However, in this example, the X capacitor 40 is no longer as Figure 3 and 4 The choke fastening portion 11 of the common mode choke 10 is not shared as shown, but must be placed behind the DC current sensor 50 in the direction of the DC plug 3 .

[0030] An additional advantage of the distributed arrangement of the filter components 10, 20, 40 is that different cooling capacities can be achieved for the filter components 10, 20, 40 depending on their respective losses and their properties via the corresponding cooling units. The cooling units can be individually coordinated with the components to be cooled, that is, not only in terms of their shape but also in terms of cooling power.

[0031] Another possibility for improving the EMC filter 1 is to position additional filter components, such as push-pull chokes, in such a way that the damping required or desired for the respective application can be achieved. This can also be achieved by freeing up installation space at a suitable location due to the positioning of the other filter components 10, 20, 40.

[0032] The EMC filter concept of the drive inverter achieves a reduction in the installation space for filtering. In addition, an optimal utilization of the filter components is ensured, thereby ensuring an additional damping effect via the filter components.

[0033] The exact positioning of each of the individual components depends on the respective application and use of the component.

[0034] Reference numerals list

[0035] 1 EMV filter

[0036] 10 Common mode choke

[0037] 11 Choke coil fastening part

[0038] 23 Tightening point

[0039] 3. Connection part of DC current plug

[0040] 20 Intermediate circuit capacitor with Y capacitor

[0041] 22 Y capacitor

[0042] 30 Semiconductor components

[0043] 40 X Capacitors

[0044] 50 DC Current Sensor

Claims

1. An EMC filter (1) having a plurality of filter components, the filter components comprising at least a common mode choke (10), an intermediate circuit capacitor (21), a Y capacitor (22) and an X capacitor (40), wherein: The EMC filter is formed so that each filter component can be positioned in such a way that, in addition to its respective main function, the filter component also exerts a damping effect on the EMC filter (1), wherein the EMC filter (1) also has 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, wherein a fastening portion implemented as a screw connection is provided on the housing, the fastening portion serving simultaneously as a choke fastening portion (11) for fastening the common mode choke (10) and as a grounding portion for the Y capacitor (22), A DC current sensor (50) is also provided as an additional filter component, wherein the DC current sensor is arranged between the common mode choke (10) and the X capacitor (40). or, Therein, a push-pull choke is also provided as an additional filter component, which is positioned between the common mode choke (10) and the X capacitor (40) and dimensioned depending on the damping required for the intended application.

2. The EMC filter (1) according to claim 1, wherein: The choke fastening portion (11) is formed so that the X capacitor (40) can be fastened on the side of the DC current plug (3).

3. The EMC filter (1) according to claim 1 or 2, wherein: The Y capacitor (22) is arranged adjacent to a semiconductor component (30) arranged on a circuit board (7).

4. The EMC filter (1) according to claim 1 or 2, wherein: A separate cooling unit is provided for each of the filter components.

5. The EMC filter (1) according to claim 1 or 2, wherein: The EMC filter (1) is a component of a drive inverter used in the automotive field.

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