Busbar device with snubber effect, intermediate circuit capacitor device and automobile

Abstract

The present invention relates to a busbar arrangement 2, a corresponding intermediate circuit capacitor arrangement 1 and a motor vehicle equipped with this intermediate circuit capacitor arrangement 1. The busbar arrangement 2 has electrical contact elements 3, 4. These contact elements 3, 4 extend flat parallel to one another and each form a contact surface area 6. These contact elements 3, 4 have a terminal area 7, 8 at at least one end of each of these contact elements 3, 4 as external terminals. These contact elements 3, 4 constitute a snubber capacitor. To this end, the contact surface areas 6 are separated from one another only by an electrical insulating layer 5 in a direction perpendicular to a main extension plane xz of these contact surface areas 6. Furthermore, these contact surface areas 6 extend over a large part of the total area of ​​the busbar arrangement 2 in a direction x, z extending into the main extension plane xz of these contact surface areas 6. In this case, the height of the busbar arrangement 2 perpendicular to the main extension plane xz of these contact surface areas 6 is smaller than the dimension of these contact surface areas 6 in this main extension plane xz.

Description

[Technical field]

[0001] The present invention relates to a busbar arrangement for a capacitor arrangement of an electric intermediate circuit, to a corresponding intermediate circuit capacitor arrangement and to a motor vehicle equipped with such an intermediate circuit capacitor arrangement. [Background technology]

[0002] Electrical intermediate circuits are frequently used as power storage devices for electrically coupling several power networks or sub-networks at current or voltage levels that are switched between these networks or sub-networks. In this case, various problems may arise, for example with regard to electromagnetic compatibility (EMC) and the occurrence of overshoots and oscillations during switching processes. Conventionally, such problems may be addressed, for example, by relatively expensive shielding, a relatively load- or voltage-resistant design and / or immediately preceding snubbers. However, this may result in additional weight, additional space requirements and additional costs.

[0003] Against this background, for example, EP 3512085 A1 describes a DC converter with a parasitic resonant circuit and exhibits very steep rising edges. In particular, a device is described therein, which comprises a DC converter with a semiconductor switch and a current source. In this case, the DC converter has an AC resonant circuit that is determined by the parasitic characteristics of the DC converter. Furthermore, a control device is provided for switching the semiconductor switch by performing a switching process. The control device is configured to perform the switching process with a switching period that is smaller than the period of the resonant frequency of the AC resonant circuit. Furthermore, the control device is configured to select the time point of the switching process such that the current supplied by the current source generates an overshoot in the semiconductor switch of at most 30% with respect to the rest state of the semiconductor switch. Thus, low losses and overvoltages are possible in the DC converter.

[0004] As an alternative approach, DE 10 2015 115 145 A1 describes a rectifier with a relatively high integration density, which reduces the implementation costs and which is less susceptible to noise and / or has reduced parasitic effects. For this purpose, the rectifier described therein comprises a semiconductor module, an electric capacitor and a cooling body with a pin-shaped or rib-shaped cooling structure. In this case, the electric capacitor is directly fastened to the cooling body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] European Patent Application Publication No. 3512085 [Patent Document 2] DE 102015115145 A1 Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the invention is to make it possible to realize a power system with an intermediate circuit in a very efficient manner. [Means for solving the problem]

[0007] According to the invention, this problem is solved by the subject matter of the independent claims. Possible and further configurations of the invention are disclosed in the dependent claims, the description and the figures.

[0008] The busbar arrangement according to the invention is provided or configured for an intermediate circuit capacitor arrangement. In other words, the busbar arrangement can electrically connect or contact a number of individual capacitors or wraps which can be used in combination with one another as intermediate circuit capacitors. The busbar arrangement according to the invention has a first electrical contact element and a second electrical contact element. These contact elements can also be called positive and negative contact elements and can therefore be used for both electrical polarities. Each of these contact elements forms a contact surface area in which they extend flat and parallel to one another. These contact surface areas are used as electrical connectors or electrical contacts for a number of capacitors of the intermediate circuit capacitor arrangement. In this case, these capacitors can in particular be wound capacitors, i.e. wraps or film wraps as capacitance cells. These capacitors or wraps can then be electrically connected to these contact elements in their contact surface areas in order to form the intermediate circuit capacitor arrangement. Furthermore, each of these contact elements has at least one end of this contact surface area, possibly each at two, in particular mutually opposing, terminal areas which are connected to each of said ends as external terminals. These terminal areas or external terminals are thus used or serve as terminals or contacts for external components or devices, such as power sub-networks connected to one another by intermediate circuit capacitor arrangements, the AC side and / or the DC side of an intermediate circuit or an apparatus including the same, etc. These terminal areas may thus be formed or moulded integrally, monolithically or integrally with the respective contact surface areas or may be otherwise connected to the respective contact surface areas.

[0009] According to the invention, it is proposed that the contact elements have snubbers or snubber capacitors. The snubbers or snubber capacitors are therefore not RC elements, since a corresponding R component, i.e. a resistance component, arises due to the dielectric loss tangent in the electrical insulator or insulating film between these contact elements and due to the skin effect and the proximity effect in the current-carrying parts of the busbar arrangement. Here, the snubber capacitors may also be called high-frequency X-capacitors. The present invention or the snubber capacitors proposed or constructed according to the invention can therefore be understood as an improvement of an effective X-capacitor. In contrast, a wrap which is also in electrical contact acts as a capacitor exclusively for lower frequencies. The busbar arrangement can therefore be used or function as a damping element for damping unwanted oscillations in the respective power network or in the respective converter cell, for example during switching processes. In the case of conventional busbar arrangements of intermediate circuit capacitor arrangements, resonances frequently occur, which are determined, for example, by the intrinsic inductance of the respective busbar or the respective converter cell. As a result, voltage overshoots and oscillations can occur with undesirable relatively large amplitudes and relatively long-lasting damping or over-oscillating behavior. This may be beneficially reduced by the busbar arrangement of the present invention or a structure or configuration of the busbar arrangement to maximise the capacitance of the busbar arrangement.

[0010] For this reason, according to the invention, the contact surface areas are separated from one another in a direction perpendicular to the main extension plane of the contact surface areas only by an electrical insulating layer or high-voltage insulator arranged between the contact elements or the contact surface areas of the contact elements, in which case in particular the insulating layer is thinner in the contact surface areas of both contact elements than the contact areas themselves, in other words the contact surface areas of the contact elements are therefore arranged as close or as closely adjacent as possible while simultaneously meeting the electrical insulation requirements and the given manufacturing tolerances.

[0011] In particular, the main plane of extension of these contact surface areas may be the main plane of extension of the busbar arrangement in which the capacitor is arranged or mounted in the defined mounting position, i.e. in an area of ​​this busbar arrangement that is electrically contacted by the contact element, which may thus have other areas that may extend, for example partially or at least approximately perpendicularly to the contact surface area or the main plane of extension of the contact surface area, in other planes.

[0012] Furthermore, according to the invention, it is proposed that the contact surface areas extend over at least a large part of the total area or overall dimension of the busbar arrangement in a direction extending in the main extension plane of the contact surface areas - or possibly over the entirety of the corresponding intermediate circuit capacitor arrangement - in other words, the area of ​​the contact surface areas is therefore maximized, taking into account certain requirements or constraints regarding the overall required mounting space, in particular the mounting space required for the capacitors of the corresponding intermediate circuit capacitor arrangement, pre-set weight and / or cost limitations, etc. Furthermore, the proposed minimization according to the invention of the spacing of the contact elements or the contact surface areas perpendicular to the main extension plane of the contact elements and the configuration of the contact elements or the contact surface elements as flat extending areas or plate-like or plate-shaped areas with a maximum area maximizes the capacitance of the busbar arrangement.

[0013] Furthermore, according to the invention it is proposed that the total or maximum dimension of the busbar arrangement perpendicular to the main extension plane of these contact surface areas is smaller than the total area or total dimension of these contact surface areas or busbar arrangements in the main extension plane of these contact surface areas, i.e. in one or both directions extending into this main extension plane. In other words, the height of the busbar arrangement can therefore be smaller than the length and / or width of this busbar arrangement as a whole or of the contact surface areas in the main extension plane of this busbar arrangement. The busbar arrangement is therefore formed or shaped as coplanar or flat as possible. This can reduce or minimize the inductance of the busbar arrangement.

[0014] The configuration of the busbar arrangement proposed according to the invention is based on the realization that with this configuration an increased capacitance and a reduced inductance can be achieved compared to conventional busbars, and thus the busbar arrangement of the invention can be used or function as a snubber or high-frequency snubber (HF snubber). Thus, without significant drawbacks, a synergistic effect or a synergistic, i.e. multifunctional use of the busbar arrangement can be achieved for the electrical contact of a plurality of capacitors of a corresponding intermediate circuit capacitor arrangement and further as a snubber. Also, due to the very large area configuration of the contact elements or contact surface elements, the material thickness of said contact elements or contact surface elements can be reduced without an increase in electrical resistance. Thus, an improved EMC behavior can be achieved, voltage overshoots and electrical oscillations can be reduced, and expensive and cumbersome filter means can be saved or simply constructed. Thus, an improved, more compact and cheaper configuration of the intermediate circuit or of an electrical device or circuit comprising an intermediate circuit can be achieved.

[0015] In a possible configuration of the invention, the insulating layer has a thickness, i.e. material thickness or layer thickness, of at most 500 μm in the direction perpendicular to the main extension plane of the contact surface area. This allows for effective electrical insulation of both contact elements from one another, even taking into account typical manufacturing variations. Thus, at the same time, a very large capacitance of the busbar arrangement and thus a very large or effective action as a snubber can be achieved. In this case, the thickness of the insulating layer can be, for example, at least 100 μm, in order to ensure reliable electrical insulation.

[0016] In another possible configuration of the invention, the insulating layer has a thickness of ε r >>1. In other words, the insulating layer is therefore manufactured or formed from a high dielectric constant material. For example, the insulating layer may have a dielectric constant of at least 3.9 or at least 6 or at least 10 etc. Such a configuration of the insulating layer may also contribute to maximizing the capacitance of the busbar arrangement, thus further increasing the action of the busbar arrangement as a snubber.

[0017] In another possible configuration of the invention, the contact surface area (which may also be referred to here as the upper contact surface area or the contact surface area of ​​the upper contact element) facing the capacitors of the intermediate circuit capacitor arrangement in the regular mounting position has at least one recess or through hole that reaches the other contact surface area. In particular, for each regularly arranged capacitor or wrap, one, in particular exactly one such recess or through hole can be provided or formed in the upper contact surface area. In order to electrically contact the respective capacitor or wrap to the other, i.e. the lower, contact surface area or contact element, the respective capacitor can be placed in this through hole or a corresponding electrical connection can be performed by means of this through hole. The configuration proposed here allows the realization of a very simple and compact, i.e. mounting space-saving, configuration or intermediate circuit capacitor arrangement. Thus, for example, electrical connection lines for the capacitors can be saved or shortened.

[0018] In another possible configuration of the invention, the terminal areas arranged at one end of the contact surface areas are formed identically in a direction perpendicular to the main extension plane of the contact surface areas, at least with a height difference corresponding to the spacing of the contact surface areas perpendicular to one another in the main extension plane of the contact surface areas. The terminal areas can therefore have the same shape and dimensions or the same orientation, with the exception of this spacing or height difference. The terminal areas can in particular be terminal areas on the DC side, i.e. for a DC or power flow voltage connection of a busbar arrangement or a contact element. The proposed Due to the configuration of these terminal areas, the dimensions and area of ​​the busbar arrangement in one or both of the two planes perpendicular to the main extension plane of these contact surface areas or in the corresponding projection plane can be reduced or kept very small compared to conventional busbars. This can reduce or very small the inductance of the busbar arrangement and therefore can contribute to very small or small ESL (Equivalent Series Resistance) of the corresponding intermediate circuit capacitor arrangement, thus supporting the action or function of the busbar arrangement as a snubber. In particular, these terminal areas can have a number of partial areas arranged parallel to these contact surface areas but spaced apart from these contact surface areas in a direction perpendicular to the main extension plane of these contact surface areas. These partial areas of different terminal areas can then be arranged in the same plane, i.e. at the same distance measured from one of these contact surface areas in a direction perpendicular to the main extension plane of these contact surface areas. Alternatively, the partial areas can be arranged one above the other or one behind the other, ie overlapping or covering one another, as viewed perpendicularly to the main plane of extension of the contact surface areas.

[0019] In another possible configuration of the invention, the busbar arrangement has a terminal inductance, or ESL, of less than 1 nH. In particular, the terminal inductance or ESL can be much smaller than 1 nH.

[0020] For this purpose, for example, the areas or dimensions in a plane or projection at least perpendicular to the main extension plane of these contact surface areas can be appropriately limited. The proposed configuration can therefore pre-set or provide an appropriate design, shape or construction margin for the busbar arrangement. The proposed configuration of the busbar arrangement allows this to be used efficiently and appropriately as a snubber in practical applications, such as in converter cells of inverters for vehicle accumulators in motor vehicles, possibly making it possible to dispense with additional snubber capacitors and / or to significantly reduce the dielectric strength of the components or devices used.

[0021] Another feature of the present invention is an intermediate circuit capacitor arrangement comprising a busbar arrangement according to the present invention and a capacitor, in particular a wound capacitor, electrically connected or contacted by said busbar arrangement. The intermediate circuit capacitor arrangement according to the present invention may in particular be an intermediate circuit capacitor arrangement as described above in relation to the busbar arrangement according to the present invention or may correspond to said intermediate circuit capacitor arrangement. The intermediate circuit capacitor arrangement according to the present invention may therefore have the same properties and / or characteristics or may have the properties and / or characteristics as described above in this regard.

[0022] In another possible configuration of the invention, the capacitors are configured as a plurality of wound capacitors. These wound capacitors are then arranged on the contact surface area such that their winding axes are perpendicular to the main extension plane of the contact surface area. The winding axis of the wound capacitor means here the axis about which the wrap is wound. This can therefore correspond to the cylindrical central longitudinal axis of the respective capacitor. Here, therefore, the capacitors are arranged upright on the contact surface area side by side with their winding axes parallel to one another or aligned with one another. This can therefore allow for a space-saving design of the intermediate circuit capacitor arrangement, despite the very large area of ​​the contact surface area at the same time. This can therefore allow for a very simple and quick electrical connection or contacting of the capacitors. Each of these capacitors can be cylindrical and arranged in a regular array or regular pattern, particularly in a close-packed manner, i.e. offset from one another by the radius of the cylinder.

[0023] In another possible configuration of the invention, the capacitors are arranged in a compact group, the dimensions of which in the main extension plane of the contact area approximately correspond to the dimensions of this group of capacitors in the direction of the main extension plane of the contact area. In other words, the dimensions or area of ​​the contact area in the main extension plane of the contact area are limited by or are limited to the dimensions or area of ​​the group of capacitors. In this way, the dimensions or required mounting space of the intermediate circuit capacitor arrangement can be reduced or limited to the minimum dimensions determined by the proposed capacitors or the minimum mounting space required for the proposed capacitors. Thus, for example, the housing of the intermediate circuit capacitor arrangement, in which the capacitors or the busbar arrangement are arranged or accommodated, can be made very compact. Thus, a very good compromise can be found between minimizing the required mounting space, weight and production costs of the intermediate circuit capacitor arrangement and maximizing the capacitance or snubber effect of the busbar arrangement. The contact surface area substantially corresponding to the dimension or area of ​​the group of capacitors can mean, for example, that the contact surface area extends beyond the group of capacitors in one, in particular only in one or exactly one direction or dimension, in particular only to the extent that is minimally necessary for forming or connecting to a terminal area, whereas in another direction or dimension of the main extension plane of the contact surface area, i.e. perpendicular to the main extension plane, the contact surface area can, for example, reach exclusively or exactly to the outer surface or outer wall of the group of capacitors.

[0024] Another aspect of the invention is a motor vehicle comprising a vehicle accumulator battery and an intermediate circuit capacitor device of the invention electrically connected to the vehicle accumulator battery. The motor vehicle of the invention may in particular be or correspond to the motor vehicles described above in relation to the other aspects of the invention and may therefore have some or all of the properties and / or characteristics described above.

[0025] Further features of the invention can be taken from the claims, the figures and the description of the figures. The features and combinations of features described in the above specification and shown below only in the description of the figures and / or in the figures can be used not only in the respective combinations described above but also in other combinations or in specific fields, without departing from the scope of the invention. [Brief description of the drawings]

[0026] [Figure 1] FIG. 2 is a schematic perspective view of a portion of a busbar arrangement for an intermediate circuit capacitor arrangement; [Diagram 2] 4 is a schematic graph illustrating the snubber effect of the busbar arrangement compared to a conventional busbar arrangement; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] 1 is a schematic perspective view of a part of an intermediate circuit capacitor arrangement 1 with a busbar arrangement 2. The busbar arrangement 2 comprises a first contact element 3, a second contact element 4 and an insulating layer 5 arranged between these contact elements. The contact elements 3, 4 are thus electrically conductive, whereas the insulating layer 5 is non-conductive and is in particular made entirely or partly from an insulator with a high dielectric constant.

[0028] Each of the contact elements 3, 4 has a contact surface area 6. In this contact surface area 6, the contact elements 3, 4 run flat and parallel to one another, i.e. are formed like a plate. Furthermore, the contact elements 3, 4 have a respective connection area 7 at least at one end - here, for example at only one end - or at least on one side. At the opposite end or opposite side of the contact elements 3, 4 or of the contact surface area 6, a further connection area may also be formed in each case.

[0029] For purposes of illustration and reference, a coordinate system is shown having spatial directions x, y, and z.

[0030] Here, these contact surface areas 6 therefore extend flat in the xz-plane or have a maximum area or dimension of these contact surface areas 6. In contrast, the busbar device 2 may in particular have or occupy an area or dimension smaller than said area or dimension perpendicular to the xz-plane, i.e. in the xy- or yz-plane.

[0031] Due to the configuration of the busbar arrangement 2 proposed here, the busbar arrangement 2 simultaneously has a very large capacitance C bar It is possible to have a very low ESL while still exhibiting the above-mentioned characteristics. In this case, C bar =ε0 ε r ·A / d holds. Here, ε0 is the dielectric constant of a vacuum, and ε r denotes the relative permittivity of the insulating layer 5, A denotes the area (wherein the contact elements 3 and 4 are respectively arranged locally parallel to one another via this insulating layer 5 so as to be separated over this area), i.e. the area consisting of the contact surface areas 6 in particular or in the xz-plane, and d denotes the spacing of the contact surface areas 6 in the y-direction, i.e. the thickness of the insulating layer 5.

[0032] The busbar device 2 thus now acts as a high frequency X-capacitor, i.e. as a high frequency snubber, for damping oscillations and for reducing voltage overshoots or voltage overpeaks.

[0033] The intermediate circuit capacitor arrangement 1 also has a number of capacitors 8, which are likewise illustrated here. These capacitors 8 are arranged upright on the contact surface area 6 and together may constitute or provide the intermediate circuit capacitance. In contrast to the intermediate circuit capacitor arrangement 1 illustrated here, the capacitors 8 for actually constituting the intermediate circuit capacitor arrangement 1 may in particular also be arranged more closely packed. In particular, the contact surface area 6 can be designed in such a way that it at least approximately covers the total area in the xz plane required by these capacitors 8, but extends beyond these capacitors 8 only if this is required for the construction.

[0034] In order to further illustrate the damping or snubbering effect of the busbar arrangement 2, Fig. 2 exemplarily and diagrammatically shows a graph, in which two courses of the intermediate circuit voltage U against time t are plotted. In particular, here for a switching process, a transient oscillation curve 9 generated by the busbar arrangement 2 and a reference curve 10 are shown. The reference curve 10 would occur if a conventional busbar were used instead of the busbar arrangement 2 in an otherwise identical intermediate circuit or an otherwise identical intermediate circuit capacitor arrangement 1. It is clearly recognizable here that due to the configuration of the busbar arrangement 2 and the snubbering effect provided or obtained by it, the transient oscillation curve 9 has a voltage peak 11 which is clearly smaller than the corresponding reference voltage peak 12, i.e. the maximum value of the reference curve 10. Furthermore, the transient oscillation curve 9 exhibits a significantly lower oscillation frequency than the reference curve 10. This shows that, without the need for additional components, the busbar arrangement 2, by virtue of its configuration for realising a parasitic capacitance, can reduce voltage overshoots and in particular damp high frequency oscillations during operation of the intermediate circuit capacitor arrangement 1 or an electrical system comprising this intermediate circuit capacitor arrangement 1.

[0035] In summary, therefore, the described example shows how a high frequency snubber for an intermediate circuit capacitor can be realized simply and efficiently. [Explanation of symbols]

[0036] 1 Intermediate circuit capacitor device 2 Busbar device 3 First contact element 4 Second contact element 5. Insulation layer 6 Contact surface area 7 Connection Area 8 Capacitors 9 Transient vibration curve 10 Reference curve 11 Voltage Peak 12 Reference voltage peak U Intermediate circuit voltage t time x,y,z spatial directions

Claims

1. A busbar arrangement (2) for an intermediate circuit capacitor arrangement (1) having a first contact element (3) and a second contact element (4), The first contact element (3) and the second contact element (4) extend parallel to each other in a flat shape, and each of the first contact element (3) and the second contact element (4) forms a contact surface area (6) as a connection surface for a plurality of capacitors (8), and has terminal areas (7, 8) connected to each of the at least one end of the contact surface area (6) as external terminals, These contact elements (3, 4) constitute a snubber capacitor, and thus - said contact surface areas (6) are separated from one another perpendicularly to the main plane of extension (x-z) of said contact surface areas (6) only by an electrically insulating layer (5); - these contact surface areas (6) extend over a large part of the total area of ​​the busbar device (2) in a direction (x, z) that extends in the main extension plane (xz) of these contact surface areas (6); the height of said busbar arrangement (2) perpendicular to said plane of main extension (x-z) of these contact surface areas (6) is smaller than the dimensions of these contact surface areas (6) in this plane of main extension (x-z).

2. 2. The busbar arrangement (2) according to claim 1, characterized in that the insulating layer (5) has a thickness of at most 500 μm.

3. The insulating layer (5) has a thickness of ε ｒ 3. The busbar arrangement (2) according to claim 1 or 2, characterized in that it has a relative permittivity of >>1.

4. 3. The busbar arrangement (2) according to claim 1 or 2, characterized in that the contact surface area (6) facing the plurality of capacitors (8) in their regular mounting positions has at least one recess, in particular one recess per capacitor (8), as a through hole leading to another contact surface area (6).

5. 3. The busbar device according to claim 1, wherein the terminal areas arranged at one end of the contact surface areas are formed identically up to a height difference corresponding to at least the spacing between the contact surface areas in a direction perpendicular to the main extension plane of the contact surface areas.

6. 3. The busbar arrangement (2) according to claim 1 or 2, characterized in that the busbar arrangement (2) has a terminal inductance of less than 1 nH.

7. An intermediate circuit capacitor arrangement (1) comprising the busbar arrangement (2) according to claim 1 or 2 and a plurality of capacitors (8) electrically connected to the busbar arrangement (2).

8. 8. The intermediate circuit capacitor arrangement (1) according to claim 7, characterized in that the capacitors (8) are configured as wound capacitors (8) and are arranged on the contact surface areas (6) so that the winding axes of the capacitors (8) are perpendicular to the main extension plane (x-z) of the contact surface areas (6).

9. 9. The intermediate circuit capacitor arrangement (1) according to claim 8, characterized in that the capacitors (8) are arranged in a compact assembly, and the dimensions of the contact surface areas (6) in their main plane of extension (x-z) approximately correspond to the corresponding dimensions of the assembly of the capacitors (8).

10. 10. A motor vehicle comprising an electric vehicle battery and an intermediate circuit capacitor arrangement (1) electrically connected to the electric vehicle battery according to claim 9.

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