EMC filter for power converter and power converter

Abstract

EMC filter assembly (1, 23, 27) for a power converter, comprising a first electrical connection suitable for connecting a first output terminal of a battery to a first power supply terminal of a power converter, at least one first inductor (7), which forms part of the first electrical connection, at least one first class Y capacitor (11, 12, 34, 35), connected between the first electrical connection and ground, a second electrical connection suitable for connecting a second output terminal of a battery to a second power supply terminal of the power converter, at least one second inductor (10), which forms part of the second electrical connection, at least one second class Y capacitor (13, 14, 36, 37), connected between the second electrical connection and ground, at least one class X capacitor (15, 33),connected between the first electrical connection and the second electrical connection, wherein at least the first inductor (7), at least one first-class Y capacitor (11, 12, 34, 35), at least the second inductor (10), at least one second-class Y capacitor (13, 14, 36, 37), and at least one class X capacitor (15, 33) are received and pre-assembled in a housing (17, 24, 30). Figure for summary: Fig. 1,

Description

Title of the invention: EMC filter for power converter and power converter

[0001] The invention relates to an EMC filter assembly for a power converter, comprising: a first electrical connection adapted to connect a first output terminal of a battery to a first power supply terminal of a power converter, at least a first inductor, which is part of the first electrical connection, at least a first class Y capacitor, connected between the first electrical connection and ground, a second electrical connection adapted to connect a second output terminal of a battery to a second power supply terminal of the power converter, at least a second inductor forming part of the second electrical connection, at least a second class Y capacitor connected between the second electrical connection and ground, and at least a class X capacitor connected between the first electrical connection and the second electrical connection.

[0002] Modern electric vehicles include a power converter, in particular an inverter, which is connected to a battery and generates alternating current used to drive one or more electric motors. The trend is to place the inverter close to the electric motor. However, this creates harsh environmental conditions for the inverter components. It is therefore necessary to use an EMC filter for the power converter. A conventional EMC filter generally comprises a first electrical connection, a first inductor, at least one first class Y capacitor, which is connected between line and ground ("line to ground"), a second electrical connection, at least one second inductor, at least one second class Y capacitor, and at least one class X capacitor, which is connected between the first and second electrical connections ("line to line").

[0003] Traditionally, several specific EMC filter sets are used for different inverters. However, manufacturing is difficult due to the wide variety of parts, for example, when different housings with different EMC filter sets are used.

[0004] In addition, some EMC filter assemblies have been found to be sensitive to vibrations.

[0005] The object of the present invention is therefore to provide an EMC filter assembly that can be manufactured easily and is mechanically robust.

[0006] This objective is achieved by means of a set of EMC filters for a power converter, comprising: a first electrical connection intended to connect a first output terminal of a battery to a first power supply terminal of a power converter, at least one first inductor, which is part of the first electrical connection, at least one first class Y capacitor, connected between the first electrical connection and ground, a second electrical connection intended to connect a second output terminal of a battery to a second power supply terminal of the power converter, at least one second inductor, which is part of the second electrical connection, at least one second class Y capacitor, connected between the second electrical connection and ground, at least one class X capacitor, connected between the first electrical connection and the second electrical connection, in which at least the first inductor, at least the first class Y capacitor, at least the second inductor,at least the second class Y capacitor and at least the class X capacitor are received and pre-assembled in a housing.

[0007] In the inventive EMC filter, at least the first inductor, at least the first class Y capacitor, at least the second inductor, at least the second class Y capacitor and at least the class X capacitor are received and pre-assembled in a housing.

[0008] In particular, at least the first inductor, at least the first class Y capacitor, at least the second inductor, at least the second class Y capacitor and at least the class X capacitor are arranged in the same housing.

[0009] For example, the housing is a single piece, such as a molded part.

[0010] The invention is based on the idea that all the parts of the EMC filtering assembly can be pre-assembled, so that the EMC filtering assembly is a prefabricated component that can be easily mounted in a power converter, in particular in an inverter, as a single part.

[0011] Tests have shown that the inventive EMC filter does not suffer from vibration problems, but is, on the contrary, very resistant to vibration. The pre-assembly of the various parts of the EMC filter has the additional advantage that the different components of the EMC filter can have wider tolerances without this causing any problems.

[0012] In the inventive EMC filter assembly, the first and / or second inductance is formed from a magnetic core, a nanocrystalline core, or a ferrite. The specific type of electronic component used as the inductance is chosen according to the requirements of the application for which the EMC filter assembly is intended.

[0013] Within the framework of the invention, it is particularly preferable that the first inductor at least, the first class Y capacitor at least, the second inductor at least, the second class Y capacitor at least and the class X capacitor at least be glued and / or resin-coated in the housing. Encasing the components in resin within the housing ensures that all EMC filter components are securely embedded, thus providing mechanical protection against damage. Being surrounded and encased in resin also automatically dampens vibrations.

[0014] In the invention, it can also be envisaged that the first electrical connection and / or the second electrical connection extend through an opening in a magnetic core, preferably a nanocrystalline core. This arrangement guarantees the desired EMC filtering effect.

[0015] Preferably, the first and / or second electrical connection consists of busbars, preferably with a rectangular cross-section. The busbars are used to connect a battery output terminal to a power supply terminal. The busbars can be bent, if necessary, to adapt them to different installation environments.

[0016] In the inventive EMC filter assembly, the housing is preferably made of an electrically insulating material, preferably a plastic material. When a plastic material is used for the housing, it automatically insulates the electrical components it contains, thereby preventing unwanted or dangerous electrical contacts and fires.

[0017] To facilitate mounting the housing on a substrate, it is preferable that the housing include at least one through hole and / or at least one tab with a through hole for securing the housing. The housing can then be secured using screws or rivets, which are inserted into the through holes and / or tabs.

[0018] According to a preferred embodiment of the invention, the first electrical connection comprises at least two first inductors and / or the second electrical connection comprises at least two second inductors, the first or second inductors each being connected in series. When two inductors are used connected in series, their respective inductances add up. Consequently, it is possible to use two small inductors instead of one large inductor, which can be advantageous in terms of installation space.

[0019] The invention may provide that at least the first inductor, at least the first class Y capacitor, at least the second inductor, at least the second class Y capacitor, and at least the class X capacitor are arranged on a printed circuit board (PCB) or on a connection grid. All the electronic components of the entire EMC filter may be pre-assembled on a printed circuit board or on a connection grid. The pre-assembled printed circuit board or connection grid is then installed in an enclosure. Pre-assembling the electronic components helps to simplify and accelerate the manufacturing and assembly process.

[0020] For example, the class X capacitor is arranged with a length direction perpendicular to the length direction of at least one class Y capacitor. The length of the capacitor corresponds to a line including the two connection terminals of the capacitor.

[0021] For example, all class Y capacitors are arranged in the same lengthwise direction.

[0022] For example, the class X capacitor is placed between the class Y capacitors.

[0023] For example, all the capacitors are arranged on the same side of the first and second inductance.

[0024] For example, all the capacitors are arranged adjacently.

[0025] For example, the EMC filter comprises only a class X capacitor and several Class Y capacitors, for example 4 class Y capacitors.

[0026] In addition, the invention relates to a power converter, in particular an inverter, for an electric motor.

[0027] The inventive power converter comprises a DC coupling capacitor, power electronic components and an inventive EMC filter as described above.

[0028] The invention is explained with the aid of preferred examples with reference to the drawings. The drawings are schematic and show: [Fig.1] is XX.

[0029] Fig. 1 is a first example of an inventive EMC filter assembly in a perspective and partially sectional view.

[0030] [Fig.2] is another view of the EMC filter assembly illustrated in [Fig.1].

[0031] Fig. 3 is another example of an inventive EMC filter assembly.

[0032] Fig. 4 is another example of an inventive EMC filter assembly.

[0033] [Fig. 1] illustrates a first embodiment of an EMC filter assembly 1 comprising a first electrical connection, which is in the form of a busbar 2. The busbar 2 has a rectangular cross-section and is configured to connect a first output terminal of a battery to a first power supply terminal of a power converter. The power converter can, for example, be an inverter. The EMC filter assembly 1 further comprises a second electrical connection, which is also made of a busbar 3 with a rectangular cross-section. The end sections on both sides of the conductive bars 2, 3 are provided with through holes 4, so that the conductive bars 2, 3 can easily be connected to electrical terminals. As shown in [Fig. 1], the central sections of the two conductive bars 2, 3 are parallel. On one side of the EMC filter assembly 1, the end sections 5, 6 Busbars 2, 3 are bent to accommodate a specific installation environment.

[0034] The central sections of the busbars 2, 3 are surrounded by a first inductor 7, which is in the form of a nanocrystalline core. The first inductor 7 has a cubic shape and is provided with two rectangular openings 8, 9 arranged parallel to each other. In addition, a second inductor 10 of identical shape, also consisting of a nanocrystalline core, is arranged next to the first inductor 7 along the longitudinal axis of the busbars 2, 3. The two busbars 2, 3 pass through the nanocrystalline core, which creates the EMC filtering effect.

[0035] In addition, the EMC filter 1 includes several class Y capacitors (Cy capacitors), which are placed around the first and second inductors 7, 10. [Fig. 1] shows the underside of the Cy capacitors with their terminals extending upwards. In the installed state, the class Y capacitors are arranged on a printed circuit board (PCB) which is not shown in [Fig. 1] for clarity. The capacitors Cy 11, 12 are arranged parallel to the longitudinal axis of the bus bars 2, 3. On the opposite side of the bus bars 2, 3, other capacitors Cy 13, 14 are arranged transversely to the bus bars 2, 3. Between the capacitors Cy 13, 14, a class X capacitor (Cx capacitor) 15 is arranged parallel to the longitudinal axis of the bus bars 2, 3. Each capacitor Cy 11, 12, 13, 14 is connected between one of the bus bars 2, 3 and ground.Capacitor Cx 15 is connected between the first busbar 2 and the second busbar 3. Each capacitor Cy 11, 12, 13, 14a and capacitor Cx 15 are received in a receptacle 16, which is a box with one open side. The receptacles 16 are mounted in a housing 17 that surrounds the EMC filter assembly 1. [Fig. 1] is a cross-sectional view showing the interior. The two inductors 7, 10 are received in receptacles 18, 19, which are represented by dashed lines, so that their interior is visible. All the capacitors, which are arranged on the printed circuit board, are pushed into their respective receptacles when the printed circuit board is mounted with the housing 17.

[0036] Figure 2 is a similar view of the EMC filter assembly 1 shown in Figure 1, except that the housing 17 is shown in its entirety. It can be seen that the housing 17 comprises a lower portion 20 and an upper portion 21, which are divided approximately halfway up. On the outer side of the housing 17, several tabs 22 are provided so that the entire EMC filter assembly can be mounted on a structure using screws or rivets. In the present embodiment, the housing 17 is made of plastic.

[0037] Figure 3 shows another model of the EMC filter 23, the structure of which is similar to that of the models in Figures 1 and 2. The EMC filter assembly 23 comprises a housing 24 through which the busbars 25, 26 extend. Inside the housing 24 are arranged two nanocrystalline cores which serve as the first and second inductors. Two first capacitors Cy 11, 12 are arranged next to the capacitor Cx 15. Two second capacitors Cy 13, 14 are arranged on the opposite side of the housing 24. The terminals of the capacitors Cx and Cy are exposed externally. In the installed state, they are embedded in a printed circuit board on which all the electronic components are mounted. During the manufacture of the EMC filter 23, the two inductors and all the capacitors Cx and Cy are pre-assembled and housed in the housing 24.These electronic components are resin-encapsulated in the 24 package, so they are firmly fixed, in order to prevent any problems due to vibrations.

[0038] Figure 4 shows another example of an EMC filter assembly 27. A printed circuit board, on which the electronic components are mounted, is not shown for clarity. Two inductors, formed from nanocrystalline cores 28, 29, are placed in a housing 30. In Figure 4, the housing 30 is shown in cross-section. Busbars 31, 32 pass through the housing 30 and are connected to the battery output terminals on one side and to the power supply terminals of a power converter on the other. A capacitor Cx 33 is placed between the first capacitors Cy 34, 35 on one side and the second capacitors Cy 36, 37 on the other side. The EMC filter assembly 27, with all the components shown in Figure 4, is pre-assembled. In this pre-assembled state, it can be mounted on a power converter or on an inverter structure.

Claims

Demands

1. EMC filter assembly (1, 23, 27) for a power converter, comprising: - a first electrical connection for connecting a first output terminal of a battery to a first power supply terminal of a power converter, - at least one first inductor (7), which forms part of the first electrical connection, - at least one first class Y capacitor (11, 12, 34, 35), connected between the first electrical connection and ground, - a second electrical connection for connecting a second output terminal of a battery to a second power supply terminal of the power converter, - at least one second inductor (10), which forms part of the second electrical connection, - at least one second class Y capacitor (13, 14, 36, 37), connected between the second electrical connection and ground, - at least one class X capacitor (15, 33),connected between the first electrical connection and the second electrical connection, characterized in that at least the first inductor (7), at least the first class Y capacitor (11, 12, 34, 35), at least the second inductor (10), at least the second class Y capacitor (13, 14, 36, 37) and at least the class X capacitor (15, 33) are received and pre-assembled in a housing (17, 24, 30).

2. EMC filter assembly according to claim 1, wherein the first and / or second inductance (7, 10) is / are formed of a magnetic core or a nanocrystalline core (28, 29) or a ferrite.

3. EMC filter assembly according to claim 1 or 2, wherein the first inductance at least (7), the first class Y capacitor at least (11, 12, 34, 35), the second inductance at least (10), the second class Y capacitor at least (13, 14, 36, 37) and the class X capacitor at least (15, 33) are glued and / or resin-coated in the case (17, 24, 30).

4. EMC filter assembly according to any one of the preceding claims, wherein the first electrical connection and / or the second electrical connection extend through an opening in a magnetic core, preferably a nanocrystalline core (28, 29).

5. EMC filter assembly according to any one of the preceding claims, wherein the first electrical connection and / or the second electrical connection are made up of bus bars (2, 3, 25, 26, 31, 32), preferably with a rectangular cross-section.

6. EMC filter assembly according to any one of the preceding claims, wherein the housing (17, 24, 30) is made of an electrically insulating material, preferably a plastic material.

7. EMC filter assembly according to any one of the preceding claims, wherein the housing (17, 24, 30) comprises at least one through hole and / or at least one lug (22) with a through hole for fixing the housing (17, 24, 30).

8. EMC filter assembly according to any one of the preceding claims, wherein the first electrical connection comprises at least two first inductances (7) and / or the second electrical connection comprises at least two second inductances (10), the first two or second inductances (7, 10) each being connected in series.

9. EMC filter assembly according to any one of the preceding claims, wherein at least one first inductor (7), at least one first class Y capacitor (11, 12, 34, 35), at least one second inductor (10), at least one second class Y capacitor (13, 14, 36, 37) and at least one class X capacitor (15, 33) are arranged on a printed circuit board (PCB) or on a connection grid.

10. Power converter, in particular inverter, for electric motor, comprising a DC coupling capacitor, power electronics and a set of EMC filters (1, 23, 27) according to any one of claims 1 to 9.

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