Highly integrated capacitor arrangement and electrically driven vehicle

Abstract

A highly integrated capacitor arrangement (100) for an electrically driven vehicle, wherein the vehicle comprises an electric machine (200), the capacitor arrangement, and a power module (240), wherein the capacitor arrangement can be coupled to the electric machine and the power module, wherein the capacitor arrangement comprises a plurality of individual capacitors (130x) arranged in a common housing (110) consisting at least partially of an electrically conductive material and at least partially surrounded by a potting compound (114), wherein the housing can be coupled to an electrical ground (220), wherein the capacitor arrangement is arranged and configured such that a low-impedance path based on a distributed interference suppression capacitor (160) is provided in order to return high-frequency interference to the power module 240,wherein a dielectric of the distributed interference suppression capacitor (160) is formed by the potting compound (114), wherein the potting compound (114) ensures a surface contact between the individual capacitors (130x) and the housing (110) for dissipating high-frequency interference, and wherein the individual capacitors (130x) are potted with the potting compound so that they are embedded therein and outer surfaces of the individual capacitors are in direct contact with the potting compound.

Description

FIELD OF THE INVENTION

[0001] The invention relates to a highly integrated capacitor arrangement and a motor vehicle. TECHNICAL BACKGROUND

[0002] An electric drive (e.g., an electric drive) for an electrically powered vehicle comprises, among other things, an electric machine (or electric motor) and a power converter, which includes, among other components, a capacitor array (DC link capacitor) and a power module. The capacitor array typically comprises several individual capacitors. Considerable heat is generated in the corresponding electrical components during operation. It is common practice to encapsulate the individual capacitors in a common plastic housing, resulting in a large number of individual heat transfer points. Therefore, heat dissipation based on existing concepts is problematic.

[0003] Another aspect concerns the switching elements included in the power module, by means of which a frequency and / or a voltage level is varied. This generates high-frequency signal components that adversely affect the functionality of the underlying electrical circuit and thus the efficiency of the electrical machine. Suppression capacitors (Y capacitors) are used to return the high-frequency signal components to the source. These are integrated into the circuits as discrete components. However, this only allows a point-like connection for returning the interference signals. In addition, the aspects of heat dissipation and the return of high-frequency interference are treated separately, so that both electromagnetic compatibility and system integration are inadequate.

[0004] DE 10 2009 055 376 A1 discloses a power capacitor with a capacitor housing having a first housing wall that can be electrically connected to a housing of an electronic unit, and with planar power supply units for supplying power to the power capacitor. A first partial region of a first power supply unit is arranged in an interior of the housing adjacent to and spaced from the first housing wall. A layer of a dielectric material is arranged between the first partial region and the housing wall.

[0005] DE 10 2013 203 614 A1 discloses a capacitor unit. This unit has at least one power capacitor and at least one interference suppression capacitor. The interference suppression capacitors and the power capacitors are enclosed, and the electrical connection of the capacitors runs within the housing.

[0006] DE 11 2016 000 457 T5 discloses a capacitor structure in which a plurality of wound capacitors are accommodated in a housing.

[0007] DE 10 2012 000 996 A1 discloses an energy storage cell arrangement with electrical connection elements, a printed circuit board and a first housing part, wherein the components are connected to the housing part at least in a force-fitting manner and wherein the electrical connection elements of the components are connected to the printed circuit board in a material-fitting manner.

[0008] DE 10 2009 058 270 A1 discloses an assembly with a driver circuit and a controller arranged on a top side of a passive heat sink and electrically connected on a bottom side of the heat sink. SUMMARY

[0009] It is an object of the invention to eliminate or at least mitigate the disadvantages of known capacitor arrangements. This object is achieved according to the invention by the subject matter of the independent patent claim.

[0010] Among other things, a highly integrated capacitor arrangement (hereinafter: capacitor arrangement) for an electrically driven vehicle is provided. The vehicle has an electric machine (e.g. an electric motor) and a power converter which includes, among other things, a power module and the highly integrated capacitor arrangement. The capacitor arrangement can be coupled to the electric machine and the power module. The coupling can be mechanical and / or electrical. The capacitor arrangement comprises a plurality of individual capacitors. The individual capacitors are arranged in a common housing (hereinafter: housing). The housing consists at least partially of an electrically conductive material. The individual capacitors are at least partially surrounded by a potting compound. The housing can be coupled to an electrical ground (neutral conductor, neutral conductor, earth potential, reference potential).The capacitor arrangement is arranged and configured to provide a low-impedance path based on a distributed interference suppression capacitor such that high-frequency interference is diverted to electrical ground (hereinafter: ground) or returned to the power module. A dielectric of the distributed interference suppression capacitor (hereinafter: interference suppression capacitor) is essentially formed by the encapsulating compound.

[0011] In the following, an interference suppression capacitor is understood to be a Y capacitor, unless explicitly stated otherwise.

[0012] The low-impedance path for dissipating high-frequency interference can be particularly well-conducting electrically. The low-impedance path can also be mechanically integrated in a particularly advantageous manner, in particular being particularly short. In particular, the path can be as short and as low-impedance as possible for dissipating the high-frequency interference to electrical ground or for returning it to the source, the power module. In other words, high-frequency interference, after being generated at the source, the power module, can be dissipated to electrical ground or returned to the source particularly quickly and efficiently with particularly high effectiveness thanks to the high electrical and mechanical integration. As a result, only a few components of the underlying circuit are actually affected by or affected by the high-frequency interference.

[0013] For the purposes of the present application, a distributed suppression capacitor is understood to be a suppression capacitor that provides a plurality of coupling points between the underlying potentials and is implemented in a non-discrete manner. In other words, a distributed suppression capacitor is not integrated as a separate, independent component, nor as a group of discrete components. Rather, the low-impedance path provided by the distributed suppression capacitor comprises a plurality of possible individual paths for dissipating the high-frequency interference, whereby the interference can be dissipated or traced back to the source particularly efficiently. Since the distributed suppression capacitor is implemented in a non-discrete form, the implementation of separate, discrete suppression capacitors can be eliminated, thereby improving production efficiency.

[0014] The capacitor arrangement can be a DC link capacitor for an electric drive or for the electric machine. The DC link capacitor can be part of a power converter, which can also include the power module and possibly other components. Another term for the power converter is power electronics.

[0015] The housing of the capacitor arrangement is mechanically and / or electrically coupled to the electrical machine. This coupling advantageously comprises a coupling via a machine housing of the electrical machine. The housing of the capacitor arrangement is advantageously directly coupled to the machine housing of the electrical machine so that the path for dissipating or returning the high-frequency interference is as short as possible. The electrical machine or the machine housing is coupled to ground. The machine housing is electrically conductive. The electrical coupling of the capacitor arrangement to the electrical machine, achieved by means of the distributed interference suppression capacitor, closes the path for returning high-frequency interference to the source. Since the mechanical coupling is as short as possible and since the housing of the capacitor arrangement is electrically conductive, the path is as low-impedance as possible.This means that the interference can be diverted to the electrical machine or its machine housing and thus to ground in a particularly simple and efficient manner with a particularly high level of effectiveness.

[0016] The individual capacitors can be coupled to the power module, which in particular can comprise a B6 bridge and can be part of a power converter. The power converter can also comprise the capacitor arrangement. For this purpose, the housing can comprise connections. The connections can be insulated from the housing of the capacitor arrangement. The power module can comprise electronic switching elements (transistors) that vary a frequency and / or a voltage level. The individual capacitors can also be coupled to a battery or a high-voltage storage device as an energy source. The supply lines to and from the individual capacitors can be integrated in a busbar. The busbar can be arranged within the housing of the capacitor arrangement. The distributed interference suppression capacitor can then have a plurality of coupling points and paths for dissipating orfor the return of high-frequency interference between, on the one hand, the individual capacitors and / or their supply lines and / or the busbar, and, on the other hand, the housing. The capacitor arrangement designed in this way provides improved electromagnetic compatibility due to the high electrical and mechanical integration, as the high-frequency interference is dissipated as quickly as possible after it occurs (at the power module). Furthermore, the capacitor arrangement also provides improved system integration, as a large number of coupling points or low-impedance paths are provided for the dissipation of the high-frequency interference. Furthermore, it is not necessary to provide discrete interference suppression capacitors within the circuit.

[0017] The potting compound ensures a surface-to-surface contact between the individual capacitors and the housing to dissipate high-frequency interference. The individual capacitors are potted with the potting compound so that they are embedded within it, and the outer surface of an individual capacitor is in direct contact with the potting compound. The potting compound can also be in direct contact with at least a two-dimensional portion of the inner wall of the housing. In this case, a surface-to-surface contact between both the individual capacitors and the housing of the capacitor arrangement can be provided by the potting compound. The potting compound can be solid or liquid. The return of interference is further improved by the surface contact using the potting compound.

[0018] The flat contact further reduces the impedance of the path for returning high-frequency interference. The flat contact can reflect the three-dimensional design of the distributed interference suppression capacitor, thus advantageously further increasing electromagnetic compatibility.

[0019] The potting compound can also have a high thermal conductivity, so that heat can be dissipated from the individual capacitors to the housing. The thermal conductivity of the potting compound can have a value between 0.13 W / m·K and 400 W / m·K, in particular a value between 0.2 W / m·K and 250 W / m·K, further in particular a value between 0.5 W / m·K and 50 W / m·K, further in particular a value between 4 W / m·K and 13 W / m·K. The housing can also comprise a material with a high thermal conductivity. The housing can therefore have a high electrical conductivity and, at the same time, a high thermal conductivity. The housing can, in particular, at least partially comprise a metal, in particular aluminum or an aluminum alloy. The housing can also be arranged and configured such that heat can be dissipated from the housing and / or such that the housing can be cooled by an active and / or passive cooling mechanism.The potting compound can then dissipate heat present or generated in the individual capacitors particularly efficiently to the housing. Since the potting compound and the housing each have high thermal conductivities, the number of heat transfers is reduced and heat dissipation is advantageously improved. Thus, the high mechanical integration provided by the potting compound also ensures particularly efficient thermal integration.

[0020] The potting compound can also be designed to ensure the positioning of the individual capacitors within the housing.

[0021] On the one hand, the potting compound can form a dielectric for the distributed interference suppression capacitor in such a way that high-frequency interference can be dissipated or redirected particularly efficiently and via the shortest possible and lowest-impedance path, thus achieving high electrical integration and electromagnetic compatibility. On the other hand, the potting compound also exhibits good thermal conductivity properties, allowing the heat from the individual capacitors to be dissipated particularly efficiently due to the high mechanical integration. Essentially, the way the interference suppression capacitor is implemented and the heat dissipated by the potting compound allows for high electrical integration, high mechanical integration, and high thermal integration to be achieved simultaneously.

[0022] The housing can comprise at least one cooling lance. The cooling lance can have a longitudinal axis that can be arranged substantially parallel to a longitudinal axis of at least one individual condenser. The arrangement can be such that the at least one individual condenser has a substantially constant average distance from the at least one cooling lance along its longitudinal axis. The average distance is understood to be a distance, averaged over the longitudinal axis of an individual condenser, between an outer surface of the individual condenser and an outer surface of the cooling lance facing the individual condenser. Alternatively, the distance between the longitudinal axes of the individual condenser and the cooling lance can be constant. A distance between the cooling lance and the corresponding individual condenser can be smaller than a diameter or a depth and width of the individual condenser. The diameter orThe depth and width can be the dimensions of the individual capacitor perpendicular to its longitudinal axis. In other words, the cooling lance is arranged parallel to at least one individual capacitor with only a small gap in between. The potting compound can be designed and arranged such that it provides a heat conduction path between the at least one individual capacitor and the at least one cooling lance. The cooling lance can advantageously increase the surface area of ​​the housing, thus increasing the cooling capacity. Furthermore, the parallel arrangement of the cooling lance to the individual capacitor enables cooling of the individual capacitor along its entire length and not just at its respective end faces, thus advantageously further improving thermal integration.

[0023] The capacitance of the interference suppression capacitor can be adjusted based on the average distance between the individual capacitors and the housing and / or an inner surface of the housing and / or the potting compound or its material. The capacitance of the interference suppression capacitor depends on the effective mutually facing surfaces of the electrodes comprising the respective potentials. These are, on the one hand, the individual capacitors and / or their leads and / or the busbar, and on the other hand, the inner surface of the housing. The inner surface of the housing can be enlarged by the cooling lance, thereby adjusting the capacitance of the interference suppression capacitor. The effective distance between the respective electrodes also influences the capacitance of the interference suppression capacitor.This can also be varied by the arrangement and dimensions of the cooling lance relative to the individual capacitor, thus providing a further degree of freedom for determining the capacitance of the suppression capacitor. Furthermore, the capacitance of the suppression capacitor depends on the dielectric properties of the material filling the space between the electrodes. In this case, this is the potting compound, so the choice of the potting compound material provides a third degree of freedom for adjusting the capacitance of the suppression capacitor.

[0024] The interference suppression capacitor can be essentially electrically conductive for signal components with a frequency between 0.15 MHz and 1000 MHz, in particular also for signal components with a frequency between 1 MHz and 500 MHz, furthermore in particular for signal components with a frequency between 5 MHz and 300 MHz, furthermore in particular for signal components with a frequency between 10 MHz and 60 MHz. The interference suppression capacitor can be configured to comply with permissible limit values ​​according to CISPR 12:2007 + A1:2009 or DIN EN 55012:2007 + A1:2009, as well as CISPR 25:2016 + COR1:2017 or EN 55025:2017 + AC:2017. The at least one interference suppression capacitor can have a capacitance between 1 nF and 1000 nF, in particular between 10 nF and 500 nF, and more particularly between 50 nF and 200 nF. This advantageously further improves electrical integration and thus electromagnetic compatibility.

[0025] The housing can also comprise a plurality of cooling lances. The plurality of individual capacitors and the plurality of cooling lances can have a corresponding arrangement at least in a partial area of ​​the internal volume defined by the housing. In this case, the average distances between the individual capacitors and the cooling lances corresponding to the respective individual capacitors can be substantially equal. The plurality of cooling lances allows each individual capacitor to be surrounded by housing material in a substantially uniform manner. This ensures a more homogeneous distribution of the encapsulation material and thus of the interference suppression capacitor. As already mentioned, this also allows the capacitance of the interference suppression capacitor to be advantageously adjusted, thus advantageously further improving electromagnetic compatibility.The plurality of cooling lances further enlarges the inner surface of the housing, so that the cooling capacity provided by the housing is also increased and at the same time all individual capacitors can be cooled more homogeneously and the heat dissipation to the housing can be improved.

[0026] The suppression capacitor can be viewed as a single suppression capacitor or, alternatively, as a plurality of suppression capacitors, each assigned to a single capacitor. In both views, however, the suppression capacitor is implemented non-discretely.

[0027] An alternative or additional suppression capacitor can be provided as a discrete component, for example, to ensure the dissipation of high-frequency interference within a specific frequency range. This can further improve electromagnetic compatibility.

[0028] The housing of the capacitor arrangement can comprise at least one cooling channel for the passage of a coolant and / or cooling fins. The heat is dissipated to the housing through the encapsulating material. The cooling channel and / or the cooling fins then advantageously improve the cooling performance of the housing. The coolant can also be used to at least partially cool the power module and / or the electric machine. For this purpose, the cooling channel enclosed by the housing can be in fluid communication with cooling channels of the power module and / or the electric machine. The housing can also be cooled indirectly via the machine housing of the electric machine.

[0029] Electronic components which are generally susceptible to high-frequency interference can be arranged in the vicinity of the housing of the capacitor arrangement, e.g. on a control board. At least a part of the housing of the capacitor arrangement which faces these electronic components can comprise a section which carries magnetic flux. The entire housing can also be designed to carry a magnetic flux. The housing can also be closed. This part of the housing can comprise steel, sheet steel and / or µ-metal. The housing itself thus ensures advantageous magnetic shielding of the components arranged outside the housing from the components arranged inside the housing which may be subject to high-frequency interference, in particular the individual capacitors, their leads and the busbar.The electronic components arranged in the vicinity of the housing of the capacitor arrangement can therefore be protected by the magnetic flux-carrying section of the housing.

[0030] The individual capacitors can be film capacitors (so-called wound capacitors). Film capacitors can be manufactured efficiently and have a high dielectric strength. The individual capacitors can comprise a polypropylene film, which can have an electrically conductive coating on at least one surface. The individual capacitors can be arranged bare in the common housing. This means that the individual capacitors can be arranged in the common housing without each having an individual individual capacitor housing. The individual capacitors can also comprise other capacitor concepts such as plate capacitors, ceramic capacitors, metal-paper capacitors, electrolytic capacitors, supercapacitors, double-layer capacitors, and hybrid capacitors. The individual capacitors can interact and represent a total capacitance. The individual capacitors can be connected in parallel and / or series.

[0031] Since the individual capacitors do not have their own individual capacitor housing, the implementation of the interference suppression capacitor can be advantageously simplified. Furthermore, the number of heat transfers can be reduced, thus advantageously improving thermal contact. The conductive coating of the individual capacitors can be contacted via supply lines (DC+ / DC-). The potting compound can then provide a low-impedance path for the dissipation or return of high-frequency signal components from DC+ to the housing and thus to ground and / or from DC- to the housing and thus to ground. The capacitor arrangement can also include one or more X-capacitors between DC+ and DC-.

[0032] An electrically driven vehicle is also provided, which comprises a highly integrated capacitor arrangement as described above. Within the meaning of the present invention, electrically driven vehicles can include, in particular, land vehicles, namely, among others, off-road and road vehicles such as passenger cars, buses, trucks, and other commercial vehicles, rail vehicles (trains), but also watercraft (boats), and aircraft such as helicopters, multicopters, propeller aircraft, and jet aircraft, which have at least one electric motor used to propel the vehicle. Vehicles can be manned or unmanned. In addition to pure electric vehicles (BEVs), hybrid electric vehicles (HEVs), plug-in hybrids (PHEVs), and fuel cell vehicles (FCHVs) can also be included. BRIEF DESCRIPTION OF THE DRAWINGS - Fig. 1 shows a simplified schematic representation of a capacitor arrangement, - Fig. 2 shows a simplified schematic representation of an equivalent circuit of the capacitor arrangement, - Fig. Figure 3 shows a simplified schematic sectional view of a power converter in conjunction with an electrical machine. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] Fig. 1 shows a simplified schematic representation of a capacitor arrangement 100. The capacitor arrangement 100 comprises a housing 110. The housing 110 comprises a material that is electrically and thermally conductive. In particular, the housing material has high electrical and thermal conductivities, as is typical for a metal. In the present case, the housing 110 is made of aluminum. The housing 110 is connected to ground 220 or is directly or indirectly coupled to an electrical ground 220. The housing 110 comprises a busbar 120 (not shown). The busbar 120 comprises a plurality of terminals 122, 124. DC voltage signals DC+ and DC- are applied to the terminals 122, 124. The terminals 122, 124 are electrically insulated from the housing 110. The busbar 120 can also comprise further electronic components. The capacitor arrangement 100 also includes several individual capacitors 130x (not shown).

[0034] The housing 110 serves, among other things, to cool the components contained therein. The housing 110 comprises a plurality of cooling lances 112 that extend from one wall of the housing 110 toward an opposite wall. The individual condensers 130x are arranged within the housing 110 between the cooling lances 112. The individual condensers 130x are arranged such that each individual condenser 130x is surrounded by four cooling lances 112. However, more or fewer cooling lances 112 can also be arranged adjacent to an individual condenser 130x. In this case, a longitudinal axis of a cooling lance 112 is aligned parallel to the longitudinal axis of an individual condenser 130x. This results in a corresponding arrangement of the cooling lances 112 and the individual condensers 130x. The cooling lances 112 and the individual condensers 130x are arranged at a short distance from each other.The cooling lances 112 cause an enlargement of the surface area of ​​the housing 110, so that an increased cooling capacity is provided.

[0035] The individual capacitors 130x are electrically coupled to the busbar 120. The busbar 120 includes leads 128, 129 for the individual capacitors 130x, so that the individual capacitors 130x are coupled to the DC voltage signals DC+ and DC-. The individual capacitors 130x are arranged "naked" in the housing 110, i.e., the individual capacitors 130x do not have individual, separate capacitor housings. The individual capacitors 130x each provide a capacitance between the DC voltage signals DC+ and DC- or the terminals 122, 124. The individual capacitors 130x interact. The individual capacitors 130x can, for example, be connected in parallel and / or series, so that a total capacitance of the individual capacitors 130x is represented as the sum of the capacitances of the individual individual capacitors 130x.

[0036] The busbar 120 is coupled to a power converter 140 via terminals 122. The power converter 140 may comprise a B6 bridge. The power converter 140 may comprise semiconductor switching elements, which may in particular be contained in the power module 240. The power converter 140 may provide an alternating voltage (three-phase voltage) for an electric machine 200. The busbar 120 may be coupled to a battery 150 or a direct voltage source via terminals 124. As a result, the individual capacitors 130x, as the capacitor arrangement 100, form an intermediate circuit capacitor between a direct voltage circuit and an alternating voltage circuit. The intermediate circuit capacitor is then configured such that it can compensate for or at least reduce fluctuations in the corresponding voltage amplitudes.

[0037] The housing 110 is filled with a potting compound 114 (not shown). The potting compound 114 at least partially fills the volume between the individual capacitors 130x and the housing 110 or its cooling lances 112. The potting compound 114 has a high thermal conductivity. The potting compound 114 can be configured to dissipate heat from an internal volume defined by the housing 110 to the housing 110. Heat can be generated, for example, by the operation of the busbar 120 and / or the individual capacitors 130x.

[0038] The potting compound 114 also has dielectric properties. The potting compound 114 represents a dielectric of the interference suppression capacitor 160. The power converter 140, the busbar 120, and / or the individual capacitors 130x may contain high-frequency signal components (interference currents; harmonics). The functionality and thus the efficiency of the electric machine 200 may be impaired by these high-frequency signal components. The interference suppression capacitor 160 enables the diversion of high-frequency signal components to the housing 110 and thus to ground 220. This advantageously improves the signal quality. It is known to implement interference suppression capacitors as discrete components. In the present case, such discrete components can advantageously be eliminated by utilizing the potting compound 114 as the dielectric of the interference suppression capacitor 160. Production efficiency can thus be increased.

[0039] The properties of the interference suppression capacitor 160, particularly its capacitance, can be adjusted by adjusting the distance between the individual capacitors 130x and the housing 110 or the cooling lances 112. Furthermore, the material of the potting compound 114 can be selected accordingly. The potting compound 114 also ensures a flat contact between the individual capacitors 130x, their leads, the busbar 120, and the housing. As a result, the interference suppression capacitor is implemented three-dimensionally rather than point-like, further improving electromagnetic compatibility.

[0040] The housing 110 can comprise a cooling channel on a housing surface 117. The cooling channel can be configured to allow a coolant to flow through it, so that heat generated in the housing 110 can be dissipated. The housing 110 is configured to conduct a magnetic flux. For this purpose, at least a portion of the housing 110 can comprise sheet steel and / or µ-metal. The housing 110 can also comprise a coating made of these materials and otherwise essentially comprise aluminum or an aluminum alloy. Substantially the entire housing 110 can also conduct a magnetic flux. In particular, the housing 110 can be closed with a metal cover (not shown) that conducts magnetic flux. The housing 110 comprises fastening options 118 by means of which the housing 110 of the capacitor arrangement 100 can be mechanically connected directly or indirectly to a machine housing 210 of the electric machine 200, preferably directly.

[0041] Fig. Figure 2 shows a simplified schematic representation of an equivalent circuit of the capacitor arrangement 100. The power converter 140 is coupled to the terminals 122. The DC voltage signals DC+ and DC- are applied to the terminals 122. The individual capacitors 130a, 130b, 130c are contacted on the input side with the terminals 122 via corresponding supply lines of the busbar 120. The individual capacitors 130a, 130b, 130c are arranged in a parallel circuit. The individual capacitors 130a, 130b, 130c are coupled to the terminals 124 via additional supply lines. The terminals 124 are coupled to the battery 150. The individual capacitors 130a to 130c are arranged in the housing 110 and encapsulated with the potting compound 114. The capacitor arrangement may also include one or more X-capacitors between DC+ and DC-. The individual capacitors 130a to 130c are coupled to the housing 110 via the interference suppression capacitors 160a, 160b, 160c, 160d, 160e, and 160f.The interference suppression capacitors 160a to 160f are in . Fig. 2 as discrete components, this is for illustrative purposes only. The suppression capacitors 160x can be viewed as a single distributed suppression capacitor 160, whose dielectric is provided by the potting compound 114. To this end, the potting compound 114 has dielectric properties such that the suppression capacitor 160 is substantially electrically conductive for high-frequency signal components. There may also be more or fewer suppression capacitors 160x, but at least one. This means that the potting compound 114 can also substantially act as the dielectric of a single suppression capacitor 160. Of course, more or fewer individual capacitors 130x can be arranged in the housing 110, but at least two. The housing 110 of the capacitor arrangement 100 is mechanically coupled directly to the machine housing 210 of an electrical machine 200 by means of the fastening options 118.Both housings are electrically conductive. The machine housing 210 is coupled to ground 220. Housing 110 is then also coupled to ground 220. Housing 110 can also be directly coupled to ground 220.

[0042] Fig.3 shows a simplified schematic sectional view of a power converter 140 in conjunction with an electrical machine 200. The power converter 140 comprises, among other things, the capacitor arrangement 100 and the power module 240. The power module 240 is configured to provide electrical power using electronic switching components (semiconductor switches). For example, the power module 240 can be configured to vary a frequency or a voltage level. The power module 240 is coupled to the terminals 122. The power module 240 is coupled to the electrical machine 200 by means of the supply lines 250. The power module 240 or its semiconductor switching elements can generally generate high-frequency signal components (e.g., harmonics), which cause interference in the underlying electrical circuit and reduce the efficiency of the structure and thus also of the electrical machine 200.Therefore, the capacitor arrangement 100 provides an interference suppression capacitor 160, which is formed as a non-discrete component by the potting compound 114. The interference suppression capacitor 160 enables the high-frequency signal components to be dissipated particularly effectively through the planar coupling to ground 220 realized by the potting compound 114. This advantageously eliminates the need for interference suppression capacitors embodied as discrete components and their production steps. The planar contacting by the potting compound 114 also advantageously reduces contact resistance. The power module 240 can include a cooling structure on which the switching elements or semiconductor components of the power module 240 are arranged. The cooling structure can be formed from ceramic.Therefore, the present capacitor arrangement 100 enables the high-frequency signal components to be returned to the source via the shortest possible path and thus in a particularly efficient manner.

[0043] The housing 110 of the capacitor arrangement 100 is mechanically coupled directly to the machine housing 210 of the electric machine 200. The housing 110 is arranged on the machine housing 210 of the electric machine 200 in such a way that a low-impedance path is provided between the capacitor arrangement 100 and the electric machine 200. The capacitor arrangement 100 is arranged, in particular, very close to the electric machine 200, so that good thermal contact and a low-impedance path are provided between the power module 240, the capacitor arrangement 100, and the electric machine 200. As a result, high-frequency signal components can be returned to the source, the power module 240, particularly effectively by means of the interference suppression capacitor 160 implemented in the capacitor arrangement 100.

[0044] The power module 240 and the capacitor assembly 100 (DC link capacitor) can be parts of a converter or power converter (power electronics). The power converter comprises the power module, the capacitor assembly, and possibly other components.

Claims

[1] A highly integrated capacitor arrangement (100) for an electrically driven vehicle, wherein the vehicle comprises an electric machine (200), the capacitor arrangement, and a power module (240), wherein the capacitor arrangement is adapted to be coupled to the electric machine and the power module, wherein the capacitor arrangement comprises a plurality of individual capacitors (130x) arranged in a common housing (110) consisting at least partially of an electrically conductive material and at least partially surrounded by a potting compound (114), wherein the housing is adapted to be coupled to an electrical ground (220), wherein the capacitor arrangement is arranged and configured such that a low-impedance path based on a distributed interference suppression capacitor (160) is provided in order to return high-frequency interference to the power module 240,wherein a dielectric of the distributed interference suppression capacitor (160) is formed by the potting compound (114), wherein the potting compound (114) ensures a surface contact between the individual capacitors (130x) and the housing (110) for dissipating high-frequency interference, and wherein the individual capacitors (130x) are potted with the potting compound so that they are embedded therein and outer surfaces of the individual capacitors are in direct contact with the potting compound. [2] The highly integrated capacitor arrangement (100) according to claim 1, wherein the potting compound (114) further has a high thermal conductivity so that heat can be dissipated from the individual capacitors to the housing. [3] Highly integrated capacitor arrangement (100) according to one of the preceding claims, wherein the housing (110) comprises at least one cooling lance (112), and wherein the cooling lance has a longitudinal axis that is arranged parallel to a longitudinal axis of at least one individual capacitor (130), so that the at least one individual capacitor has a constant mean distance from the at least one cooling lance along its longitudinal axis. [4] Highly integrated capacitor arrangement (100) according to claim 3, wherein the housing (110) comprises a plurality of cooling lances (112), and wherein the plurality of individual capacitors (130) and the plurality of cooling lances have a corresponding arrangement at least in a partial region of the housing, so that average distances between the individual capacitors and the cooling lances corresponding to the respective individual capacitors are the same. [5] Highly integrated capacitor arrangement (100) according to one of the preceding claims, wherein a capacitance of the interference suppression capacitor (160) is adjustable based on an average distance between the individual capacitors (130x) and the housing (110) and / or an inner surface of the housing and / or the potting compound (114). [6] Highly integrated capacitor arrangement (100) according to one of the preceding claims, wherein the housing (110) comprises at least one cooling channel for the passage of a coolant and / or cooling fins. [7] A highly integrated capacitor arrangement (100) according to any one of the preceding claims, wherein at least a part of the housing (110) comprises a magnetic flux-conducting section. [8] Highly integrated capacitor arrangement (100) according to one of the preceding claims, wherein the individual capacitors (130x) are film capacitors or comprise other capacitor concepts. [9] Electrically driven vehicle comprising a highly integrated capacitor arrangement (100) according to one of the preceding claims.

Images