Filter arrangement, power electronics device with a filter arrangement

Abstract

A filter arrangement (FA) comprising the following is disclosed: - an electrically insulating carrier body (TK) that extends in a longitudinal direction (LR); - a first conductor (SL1) for conducting a current which extends at least partially in the longitudinal direction (LR) of the carrier body (TK) and is at least partially embedded in the carrier body (TK); - a first ferrite core (FK1) that surrounds the carrier body (TK) together with the first current conductor (SL1) embedded therein; - wherein the carrier body (TK) has a cooling channel (KK) extending at least partially in the longitudinal direction (LR) for conveying a cooling fluid, which is thermally connected to the first conductor (SL1) by the carrier body (TK) and at the same time electrically insulated from the first conductor (SL1). Furthermore, a power electronics device with a filter arrangement (FA) is provided.

Description

[0001] The present invention relates to a filter arrangement for reducing conducted electromagnetic interference and a power electronics device, such as a power inverter, a charging device (in English "OnBoard Charger") or a voltage converter, e.g. a DC-DC converter, especially for an electric drive of a vehicle, with said filter arrangement.

[0002] Filter arrangements (EMC filters) are used in many electrical systems, especially in electrically powered vehicles, to reduce conducted electromagnetic interference within the systems, particularly at system power connections, such as between high-voltage power connections on the one hand and DC link capacitors, Cy or Cx capacitors on the other, to permissible levels. Typically, the filter arrangements are positioned at the high-voltage connections of these systems or between these connections on the one hand and the system's own DC link capacitors, Cy or Cx capacitors on the other.

[0003] As is common with technical systems, there is also a general requirement for such filter arrangements to make them more efficient and compact.

[0004] The object of the present invention is therefore to make a filter arrangement more efficient and compact.

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

[0006] According to a first aspect of the invention, a filter arrangement is provided.

[0007] The filter assembly has an electrically insulating support body that extends (essentially) along a longitudinal direction.

[0008] The filter arrangement further comprises a first current conductor for conducting a current, which is at least partially embedded in the carrier body, wherein the section of the first current conductor embedded in the carrier body extends in the longitudinal direction of the carrier body.

[0009] The filter assembly also features a first ferrite core (or a first nanocrystalline core) that at least partially, and in particular in a ring-like fashion, surrounds the carrier body along with the first conductor embedded therein (perpendicular to its longitudinal direction). In other words, the first ferrite core forms a space (at least partially, and in particular completely) through which the carrier body, including the embedded first conductor and the cooling channel, extends.

[0010] The carrier body has a cooling channel for conveying a coolant, which extends at least partially in the longitudinal direction and thus parallel to the first conductor or its section embedded in the carrier body. The cooling channel or its section embedded in the carrier body is thermally connected to the first conductor via the carrier body and simultaneously electrically insulated from the first conductor by the carrier body.

[0011] By embedding the cooling channel and the conductor within the same support body, which primarily serves to support, hold, and position the ferrite core relative to the conductor, a high degree of integration between these components is achieved, resulting in a compact design for the filter assembly. Furthermore, the support body, with its integrated cooling channel, is assigned a secondary function: cooling the filter assembly. This eliminates the need for a separate cooler solely for cooling the filter assembly and its heat sources, namely the ferrite core and the conductor. This, in turn, enables a compact filter assembly design.

[0012] The surrounding arrangement of the ferrite core around the support body, including the integrated cooling channel, minimizes the heat transfer path from the ferrite core through the cooling channel of the support body to the coolant flowing through the cooling channel. Similarly, integrating the cooling channel and the conductor within the same support body reduces the heat transfer path from the conductor to the coolant in the cooling channel to a minimum. These design features, particularly the cooling channel within the support body for conveying the coolant, enable active and therefore efficient cooling of the filter assembly, specifically the ferrite core and the conductor of the filter assembly.

[0013] In addition to the aforementioned heat sources, namely the ferrite body and the conductor, which are parts of the filter assembly, the cooling channel for conveying the coolant or the carrier body with the cooling channel embedded therein also provides a possibility to actively cool (besides the filter assembly) electrical connections from the filter assembly to adjacent assemblies, such as intermediate circuit capacitors, Cy or Cx capacitors, (HV-DC) power connections, supply lines to or from high-voltage assemblies such as HV batteries, etc., which exhibit high power losses.

[0014] This in turn has the advantage that conductor cross-sections in the aforementioned electrical connections can be reduced, which in turn reduces material costs and installation space for the filter arrangement and its connections to the adjacent assemblies.

[0015] Furthermore, critical heat inputs from the heat sources of the filter arrangement into the adjacent heat-sensitive assemblies, such as the DC link capacitor, can be avoided, thereby simplifying or even eliminating measures for cooling these heat-sensitive assemblies.

[0016] This creates a way to make a filter arrangement and an electrical device with a filter arrangement more efficient and compact.

[0017] The support body can have a curved shape in the longitudinal direction.

[0018] The cooling channel can be formed as a cavity within the support body, extending in the longitudinal direction of the support body. In this case, the support body also forms the channel wall of the cooling channel.

[0019] The filter assembly can further comprise an inlet for introducing the coolant into the cooling channel and an outlet for releasing the coolant from the cooling channel, wherein the inlet and / or the outlet are fluidically connected to the cooling channel. The inlet and / or the outlet can be at least partially embedded in the support body.

[0020] The filter assembly can further include a cooling tube for conveying the cooling fluid, which is at least partially embedded in the support body and thus extends at least partially in the longitudinal direction. In this case, the aforementioned cooling channel is formed within the cooling tube. The cooling tube or cooling channel is thermally connected to the first conductor by the support body and simultaneously electrically insulated from it.

[0021] The carrier body can be formed from a molding compound or a potting compound that is molded or cast around the first conductor and the cooling channel or cooling pipe and, if necessary, also around the inlet and outlet.

[0022] Alternatively, the support body can be formed from one or more preformed body elements, in particular from one or more preformed milling body elements, which are mounted around the first conductor and the cooling channel and together form the support body.

[0023] The filter arrangement can further include a second conductor for conducting a current, e.g. a return current, which is at least partially embedded in the carrier body and is thermally connected to the cooling channel via the carrier body and at the same time electrically insulated from the cooling channel and the first conductor by the carrier body.

[0024] The two conductors can be formed, for example, by stamping and bending a metal sheet, especially a copper sheet.

[0025] The second conductor, or a section of the second conductor embedded in the support body, can extend along the longitudinal direction and be located on the side of the cooling channel facing away from the first conductor or its section embedded in the support body, with the first ferrite core furthermore at least partially encompassing the second conductor or its section embedded in the support body (perpendicular to the longitudinal direction). Thus, the cooling channel or cooling tube is positioned, particularly centrally, between the two conductors or their respective sections embedded in the support body.

[0026] The filter arrangement can further include a second ferrite core (or a second nanocrystalline core) which is arranged behind the first ferrite core in the longitudinal direction of the carrier body and at least partially surrounds the carrier body, including the first and second conductors embedded therein (perpendicular to the longitudinal direction).

[0027] The filter assembly can also include a third conductor (and possibly additional conductors) for conducting a (further) current, e.g., a phase current (or further currents), wherein the third conductor (or further conductors) is also at least partially embedded in the support body and thermally connected to the cooling channel by the support body, while simultaneously being electrically insulated from the cooling channel, the first conductor, and the second conductor. In this case, the first, second, and third conductors (or further conductors) can be arranged around the cooling channel, and in particular, spaced equally apart from one another.

[0028] According to a second aspect of the invention, a power electronics device, in particular a (power) inverter, a (vehicle-side) charging device, a (vehicle-side) power distributor, a battery device or a voltage converter, specifically a DC-DC converter, is provided.

[0029] The power electronics device comprises a previously described filter arrangement and a capacitor arrangement, in particular an intermediate circuit capacitor, with one current connection (or with two current connections), wherein the filter arrangement is electrically connected via the first current conductor to the current connection of the capacitor arrangement (or via the first and the second current conductor to each of the two current connections of the capacitor arrangement).

[0030] If the power electronics device is an inverter, it can have a filter arrangement with three or more conductors, all of which, as described above, are embedded in the carrier body and distributed around the cooling channel, and in particular spaced equally apart from one another. In this case, the three or more conductors form three or more phase output conductors of the inverter, with the filter arrangement together with the three or more conductors being connected to the phase current connection of the inverter to an electrical machine, e.g., a separately excited or a permanent magnet machine, and electrically connecting the inverter to the electrical machine on the phase current output side.

[0031] In the event that the filter arrangement has two conductors, the filter arrangement can be arranged at a DC terminal of an inverter or DC-DC converter or power distributor or battery device, with the two conductors each forming an H+ and an H-current terminal of the respective device. Brief description of the drawings: An exemplary embodiment of the invention is explained in more detail below with reference to the accompanying drawing. The drawing shows: Fig. 1 in a schematic perspective representation a section of a filter arrangement according to an embodiment of the invention; Fig. 2 in a schematic side view, a section of the Fig. 1. Filter arrangement shown. Detailed description of the drawings:

[0032] Fig. 1 and Fig. Figure 2 shows, in a schematic perspective view or a schematic side view view, a section of a filter arrangement FA according to an embodiment of the invention.

[0033] The filter arrangement FA has a carrier body TK made of an electrically insulating material, which extends in a longitudinal direction LR, which in turn has a curved profile.

[0034] The filter arrangement FA further comprises a cooling pipe KR with a cooling channel KK for conveying a cooling fluid, which is embedded in the carrier body TK and extends along the longitudinal extension direction LR of the carrier body TK.

[0035] The filter arrangement FA also has an inlet EL for letting the coolant into the cooling channel KK and an outlet AL for letting the coolant out of the cooling channel KK, each of which is located at one of two opposite ends of the cooling tube KR and is partially embedded in the carrier body TK.

[0036] As an alternative to the aforementioned cooling pipe KR, which is formed as a separate component and embedded in the support body TK, the support body TK itself can be shaped such that it has an elongated cavity extending along the longitudinal direction LR, forming a cooling channel for conveying the coolant. In this case, the support body TK also forms the channel wall of the cooling channel. Similarly, the support body TK can have sections formed at both ends of the cooling channel within the support body TK, each forming the inlet and outlet of the cooling channel.

[0037] The filter arrangement FA also features a first SL1 and a second SL2 busbar for conducting currents, e.g., a positive and a negative current, which are at least partially embedded in the carrier body TK. Sections of the respective busbars SL1 and SL2 embedded in the carrier body TK extend along the longitudinal direction LR and thus parallel to each other and to the cooling pipe KR or cooling channel. The two busbars SL1 and SL2, or their respective sections embedded in the carrier body TK, are distributed along the longitudinal direction LR on both opposite sides of the cooling pipe KR or cooling channel, as shown in [reference to diagram]. Fig. 2 is illustrated.

[0038] The two conductors SL1 and SL2 are, for example, formed from a copper sheet as stamped and bent parts. Via the carrier body TK, the two conductors SL1 and SL2, or rather their respective sections embedded in the carrier body TK, are thermally connected to the cooling pipe KR or cooling channel embedded between them in the carrier body TK. At the same time, the electrically insulating carrier body TK provides electrical insulation between the two conductors SL1 and SL2, as well as between the cooling pipe KR and the cooling channel.

[0039] The two conductors SL1, SL2 or their respective sections embedded in the support body TK, as well as the cooling pipe KR or its section embedded in the support body TK, have the same (curved) course as the support body TK.

[0040] The filter assembly FA also includes a first ferrite core FK1 and a second ferrite core FK2, each formed in the form of a ring interrupted by an air gap. The two ferrite cores FK1 and FK2 are arranged one behind the other in the longitudinal direction LR, encompassing the carrier body TK, including the embedded cooling tube KR and the two embedded conductors SL1 and SL2, transversely to the longitudinal direction LR. In other words, the two ferrite cores FK1 and FK2 each enclose a space through which the carrier body TK, including the embedded cooling tube KR and the two embedded conductors SL1 and SL2, extends. The two ferrite cores FK1 and FK2 are designed to reduce, prevent, or...Delay of core saturation - interrupted in their respective circumferential direction by an air gap, so that the two ferrite cores FK1, FK2 do not completely surround the carrier body TK including the cooling tube KR embedded therein and the two embedded current conductors SL1, SL2.

[0041] The carrier body TK can be formed from several, for example two, pre-formed milling body elements extending in the longitudinal direction LR, with corresponding contours and recesses. These elements are mounted around the cooling tube KR and the two conductors SL1 and SL2, thus jointly enclosing these components. Furthermore, the milling body elements of the carrier body TK can be pre-formed with predetermined recesses. After the carrier body TK is mounted around the two conductors SL1 and SL2, these recesses form a tubular channel that functions as a cooling channel for conveying the coolant, thereby replacing the separate cooling tube.

[0042] Alternatively, the carrier body TK can be formed from a molding compound, a potting compound, or an injection molding compound, which is shaped around the cooling tube KR and the two conductors SL1 and SL2 by molding, casting, or injection molding. In this case, the cooling channel can also be formed by a cavity in the molding / potting / injection molding material, which can be created during the molding, casting, or injection molding of the corresponding material around the two conductors SL1 and SL2 with appropriately cast-in or cast-on interfaces as an inlet and outlet.

[0043] The filter arrangement FA is connected, for example, to a DC input or DC output of a power electronics device, in particular a power inverter, a DC-DC converter, a power distributor, or a battery device, wherein the two current conductors SL1 and SL2 of the filter arrangement FA establish the current connection of the device, and the filter arrangement FA filters electromagnetic interference in the current flowing through this current connection. The device may also include a capacitor arrangement, in particular an intermediate circuit capacitor, which is electrically connected to the two current conductors SL1 and SL2 of the filter arrangement FA via its current terminals.

[0044] In another embodiment, not shown in the figures, the filter assembly can have three or more conductors, all of which are embedded in the support body and thermally connected to the cooling channel via the support body, while simultaneously being electrically insulated from each other and from the cooling channel. The conductors are arranged around the cooling channel and at equal intervals within the support body. In this case, the conductors form three or more phase output conductors of a power inverter, with the filter assembly, including the conductors, being arranged at the phase output connection of the inverter to an electric machine and electrically connecting the inverter to the electric machine on the phase output side.

[0045] The number of ferrite cores can vary depending on the required filter performance and the design of the filter cores. Ferrite cores of different sizes and shapes can also be used. It is important that all ferrite cores at least partially encircle the substrate and all conductors embedded within it, leaving only an air gap.

Claims

[1] Filter assembly (FA) comprising: - an electrically insulating carrier body (TK) that extends in a longitudinal direction (LR); - a first conductor (SL1) for conducting a current which extends at least partially in the longitudinal direction (LR) of the carrier body (TK) and is at least partially embedded in the carrier body (TK); - a first ferrite core (FK1) that at least partially surrounds the carrier body (TK) together with the first current conductor (SL1) embedded therein; - wherein the carrier body (TK) has a cooling channel (KK) extending at least partially in the longitudinal direction (LR) for conveying a cooling fluid, which is thermally connected to the first conductor (SL1) by the carrier body (TK) and at the same time electrically insulated from the first conductor (SL1). [2] Filter arrangement (FA) according to claim 1, wherein the cooling channel (KK) is formed as a cavity in the carrier body (TK) which extends in the longitudinal direction (LR) of the carrier body (TK). [3] Filter arrangement (FA) according to claim 2, further comprising: - an inlet (EL) for letting the coolant into the cooling channel (KK) and an outlet (AL) for letting the coolant out of the cooling channel (KK), - wherein the inlet (EL) and / or the outlet (AL) are at least partially embedded in the carrier body (TK). [4] Filter arrangement (FA) according to one of the preceding claims, further comprising: - a cooling pipe (KR) for conveying the coolant, which extends in the longitudinal direction (LR) and is at least partially embedded in the support body (TK), - wherein the cooling channel (CC) is formed in the cooling pipe (CR). [5] Filter arrangement (FA) according to one of the preceding claims, wherein the carrier body (TK) is formed from a molding compound or a potting compound or an injection molding compound which is molded or cast or overmolded around the first conductor (SL1) and the cooling channel (KK). [6] Filter arrangement (FA) according to any one of claims 1 to 4, wherein the carrier body (TK) is formed from several body elements which are mounted around the first current conductor (SL1) and the cooling channel (KK). [7] Filter arrangement (FA) according to one of the preceding claims, further comprising a second conductor (SL2) for conducting a further current, which is at least partially embedded in the carrier body (TK) and is thermally connected to the cooling channel (KK) through the carrier body (TK) and is at the same time electrically insulated from the cooling channel (KK) and the first conductor (SL1). [8] Filter arrangement (FA) according to claim 7, wherein the second current conductor (SL2) extends along the longitudinal direction (LR) and is located on a side of the cooling channel (KK) facing away from the first current conductor (SL1), wherein the first ferrite core (FK1) further surrounds the second current conductor (SL2). [9] Filter arrangement (FA) according to one of the preceding claims, further comprising a second ferrite core (FK2) which is arranged in the longitudinal direction (LR) behind the first ferrite core (FK1) and at least partially surrounds the carrier body (TK) together with the first conductor (SL1) embedded therein. [10] Filter arrangement (FA) according to one of the preceding claims, further comprising a third conductor for conducting a further current, which is at least partially embedded in the carrier body (TK), thermally connected through the carrier body (TK) to the cooling channel (KK) and at the same time electrically insulated from the cooling channel (KK) and the first conductor (SL1) and the second conductor (SL2), wherein the first (SL1), the second (SL2) and the third (SL3) conductors are arranged distributed around the cooling channel (KK). [11] Power electronic device comprising: - a filter arrangement (FA) according to one of the preceding claims, - a capacitor arrangement with a power connection, - wherein the filter arrangement (FA) is electrically connected to the power terminal of the capacitor arrangement via the first conductor (SL1).

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