DE102022203036A1 - DC link capacitor for an electrical module and a power converter with improved cooling as well as an electrical module, power converter and electric vehicle - Google Patents

Abstract

The invention relates to an intermediate circuit capacitor (1a..1c) for an electrical module (10, 10a, 10b), in particular for a power converter or inverter, comprising a plurality of capacitor elements (3, 3'). Furthermore, the intermediate circuit capacitor (1a..1c) comprises a one-piece housing (5a..5c) with a cooling channel (6a..6c), through which a heat transfer medium can flow, and with a compartment (6a..6c) separate from the cooling channel (6a..6c). 7a..7c'), in which the capacitor elements (3, 3') are arranged and cast with a casting compound (9, 9'). The invention also relates to an electrical module (10, 10a, 10b), in particular for a power converter, with such an intermediate circuit capacitor (1a..1c) and to a vehicle (17) with such an inverter.

Description

TECHNICAL FIELD

The invention relates to an intermediate circuit capacitor for an electrical module or for a power converter, an electrical module with such an intermediate circuit capacitor, a power converter with such an electrical module and an electric vehicle with such a power converter, the power converter preferably being designed as an inverter.

STATE OF THE ART

An intermediate circuit capacitor, an electrical module, a power converter and an electric vehicle of the type mentioned are basically known from the prior art. The problem here is the high electrical currents flowing in and out of the intermediate circuit capacitor and the relatively strong heating of the same associated with the high power density.

The EP 3 300 239 A1 in this context also discloses an arrangement comprising a power converter with power modules which are arranged on a metal plate, and a capacitor module which contains a capacitor element and a busbar for connecting the capacitor element to the power module. Furthermore, the arrangement comprises a cooling channel which is arranged in a sandwich manner between the power module and the capacitor module.

The US 2015/0334875 A1 also discloses a cooling plate for use with an electric vehicle inverter. The cooling plate includes a pocket configured to accommodate an intermediate circuit capacitor.

However, there is no simple and effective way to cool the intermediate circuit capacitor accordingly.

DISCLOSURE OF INVENTION

An object of the invention is therefore to provide an improved intermediate circuit capacitor, an improved electrical module, an improved power converter and an improved vehicle with such a power converter. In particular, a simple and effective way to cool the intermediate circuit capacitor should be specified.

The object of the invention is achieved by an intermediate circuit capacitor for an electrical module or for a power converter, in particular for an inverter, which comprises a plurality of capacitor elements (with two electrodes and a dielectric in between), each of which can have a wound, metallized plastic film and can therefore be designed as a film capacitor element. Furthermore, the intermediate circuit capacitor comprises a one-piece housing with a cooling channel through which a heat transfer medium can flow, as well as a compartment separate from the cooling channel in which the capacitor elements are arranged and cast with a casting compound. This means that the capacitor elements are arranged outside the cooling channel. In particular, the cooling channel has a closed cross section through which a liquid or gaseous heat transfer medium can flow and can be integrated into a cooling circuit.

As mentioned, the capacitor elements can be designed, for example, as film capacitor elements. For example, the plastic film can consist of polypropylene or contain this material. However, the use of other materials or capacitor technologies is also conceivable.

For example, a structure would be like this US 2016/284472 A1 conceivable. This technology is based on a prismatic monolithic polymer capacitor structure operating at temperatures above 140°C and comprising multiple interleaved radiation-hardened dielectric polymer layers and metal layers.

The object of the invention is also achieved with an electrical module, in particular for a power converter, which comprises an intermediate circuit capacitor of the type mentioned above and at least one power module with a large number of controllable electronic switches which are electrically connected to the capacitor elements, the power module being in or is arranged on the one-piece housing. The intermediate circuit capacitor is intended to smooth a DC voltage from a DC voltage source, and the power module is intended to generate an alternating voltage from the DC voltage smoothed by the intermediate circuit capacitor.

In addition, the object of the invention is achieved with a power converter, in particular with an inverter, which has an electrical module of the type mentioned above.

Finally, the object of the invention is achieved by an electric vehicle which comprises an inverter of the type mentioned above, a DC voltage source connected to the intermediate circuit capacitor and an electric drive connected to the power section, the electric The mechanical drive is mechanically coupled to the wheels of the electric vehicle.

The proposed measures allow the intermediate circuit capacitor to be manufactured in a simple manner. At the same time, the proposed arrangement has excellent cooling performance. Accordingly, intermediate circuit capacitors, electrical modules and power converters with high power density can be implemented without the electrical currents flowing therein leading to excessive heating of the intermediate circuit capacitor.

In addition, the service life of such an intermediate circuit capacitor is significantly increased. Because of the lower heating and the less fluctuating operating conditions, the capacitor elements can also be dimensioned more narrowly (i.e. with a lower safety tolerance).

Further advantageous refinements and developments of the invention result from the subclaims and from the description in conjunction with the figures.

It is advantageous if the capacitor elements are each designed without a housing and the one-piece housing is provided as the only housing for the capacitor elements without a housing. In this way, on the one hand, a simple structure of the intermediate circuit capacitor or the electrical module and, on the other hand, a very good cooling effect of the capacitor elements is achieved.

It is advantageous if the housing is made of a metal, in particular aluminum or an aluminum alloy. This means that the housing can be manufactured in a simple manner and at the same time ensures good heat dissipation from the capacitor elements. In principle, in addition to metal, other materials would also be conceivable for the housing, provided they have sufficient thermal conductivity and/or mechanical stability.

It is advantageous if the housing has several compartments in which the capacitor elements are arranged. This allows improved thermal conductivity and thus improved heat dissipation from the capacitor elements as well as higher mechanical stability of the intermediate circuit capacitor to be achieved.

It is also advantageous if the casting compound seals the capacitor elements against moisture. In this way, the capacitor elements are well protected from external influences.

It is also advantageous if the intermediate circuit capacitor has a busbar arrangement with which the capacitor elements are electrically connected in parallel. In this way, a high overall capacity of the intermediate circuit capacitor can be achieved.

It is also advantageous if the electronic switches are electrically connected to the capacitor elements via a busbar arrangement, in particular with a full-surface busbar arrangement. In this way, high currents can flow from the capacitor elements to the electronic switches without excessive electrical losses occurring

It is also advantageous if the cooling channel is closed off to the outside by the power module or a cooling structure connected to it and protruding into the cooling channel (e.g. cooling fins or cooling pins). As a result, the power module or a cooling structure connected to it can be cooled particularly well, since they are cooled directly by the cooling medium, that is, they are in contact with it.

It is also advantageous if the power module or a cooling structure connected to it (e.g. cooling fins or cooling pins) is arranged in the cooling channel. As a result, the power module or a cooling structure connected to it can also be cooled particularly well, since in this case too they are cooled directly by the cooling medium, that is to say they are in contact with it.

It is also advantageous if the power module is arranged in the area of the cooling channel, but outside of it, in or on the housing. This avoids leakage problems because the power module is not in direct contact with the cooling medium and is only cooled indirectly. To improve the cooling performance, the housing can have a cooling structure (e.g. cooling fins or cooling pins) projecting into the cooling channel in the area of the power module.

1. a) den Kühlkanal abschließt (direkte Kühlung),
2. b) im Kühlkanal angeordnet ist (direkte Kühlung) oder
3. c) vollständig außerhalb des Kühlkanals angeordnet ist (indirekte Kühlung).

In summary, the power section is thermally coupled to the housing, whereby the power module

1. a) closes the cooling channel (direct cooling),
2. b) is arranged in the cooling channel (direct cooling) or
3. c) is arranged completely outside the cooling channel (indirect cooling).

The power module can therefore be cooled indirectly or directly and can be in contact with the cooling medium or not.

The above refinements and developments of the invention can be combined in any way.

BRIEF DESCRIPTION OF THE FIGURES

• 1 ein erstes Beispiel eines Zwischenkreiskondensators in Explosionsdarstellung von schräg oben;
• 2 zeigt den Zwischenkreiskondensator aus 1 in einem Zustand, in dem die Kondensatoranordnung in das Fach des Gehäuses eingeschoben ist;
• 3 zeigt den Zwischenkreiskondensator aus 1 in einem Zustand, in dem die Kondensatoranordnung im Gehäusefach mit einer Vergussmasse vergossen ist;
• 4 zeigt ein elektrisches Modul mit dem Zwischenkreiskondensator aus 3 und mit einem Leistungsmodul in Explosionsdarstellung von schräg oben;
• 5 zeigt das elektrische Modul aus 4 in fertiggestelltem Zustand;
• 6 ein zweites Beispiel eines Zwischenkreiskondensators mit zwei Aufnahmefächern in Explosionsdarstellung von schräg oben;
• 7 zeigt den Zwischenkreiskondensator aus 6 in einem Zustand, in dem die Kondensatoranordnung in die Fächer des Gehäuses eingeschoben ist;
• 8 zeigt den Zwischenkreiskondensator aus 6 in einem Zustand, in dem die Kondensatoranordnung in den Gehäusefächern mit einer Vergussmasse vergossen ist;
• 9 zeigt ein elektrisches Modul mit dem Zwischenkreiskondensator aus 8 und mit einem Leistungsmodul in Explosionsdarstellung von schräg oben;
• 10 zeigt das elektrische Modul aus 9 in fertiggestelltem Zustand;
• 11 zeigt eine Anordnung mit zwei Kondensatoranordnungen und zwei Kühlmodulen in Explosionsdarstellung von schräg oben.
• 12 zeigt die Anordnung aus 11 in einem Zustand, in dem die Kondensatoranordnungen und die Kühlmodule in entsprechende Gehäusefächer eingesetzt sind;
• 13 zeigt die Anordnung aus 12 in einem Zustand, in dem die Kondensatoranordnungen und die Kühlmodule mit einer Vergussmasse vergossen sind;
• 14 zeigt eine Kondensatoranordnung mit einer alternativen Ausführungsform einer Stromschienenanordnung und
• 15 zeigt ein schematisch dargestelltes Kraftfahrzeug mit einem Stromrichter der vorgeschlagenen Art.

Embodiments of the invention are shown as examples in the attached schematic figures. Show it:

• 1 a first example of an intermediate circuit capacitor in an exploded view diagonally from above;
• 2 shows the intermediate circuit capacitor 1 in a state in which the capacitor assembly is inserted into the compartment of the housing;
• 3 shows the intermediate circuit capacitor 1 in a state in which the capacitor arrangement in the housing compartment is cast with a casting compound;
• 4 shows an electrical module with the intermediate circuit capacitor 3 and with a power module in an exploded view from above;
• 5 shows the electrical module 4 in completed condition;
• 6 a second example of an intermediate circuit capacitor with two compartments in an exploded view diagonally from above;
• 7 shows the intermediate circuit capacitor 6 in a state in which the capacitor arrangement is inserted into the compartments of the housing;
• 8th shows the intermediate circuit capacitor 6 in a state in which the capacitor arrangement is cast in the housing compartments with a casting compound;
• 9 shows an electrical module with the intermediate circuit capacitor 8th and with a power module in an exploded view from above;
• 10 shows the electrical module 9 in completed condition;
• 11 shows an arrangement with two capacitor arrangements and two cooling modules in an exploded view from diagonally above.
• 12 shows the arrangement 11 in a state in which the capacitor assemblies and the cooling modules are inserted into corresponding housing compartments;
• 13 shows the arrangement 12 in a state in which the capacitor arrangements and the cooling modules are cast with a casting compound;
• 14 shows a capacitor arrangement with an alternative embodiment of a busbar arrangement and
• 15 shows a schematically illustrated motor vehicle with a power converter of the proposed type.

DETAILED DESCRIPTION OF THE INVENTION

As an introduction, it should be noted that the same parts in the different embodiments are provided with the same reference numbers or the same component names, if necessary with different indices. The disclosures of a component contained in the description can be analogously transferred to another component with the same reference number or the same component name. The position information chosen in the description, such as “top”, “bottom”, “back”, “front”, “side” and so on, is also related to the figure directly described and shown and, if the position changes, correspondingly to the new one Transfer location.

The 1 until 3 show a first example of an intermediate circuit capacitor 1a in various stages of a manufacturing process. Specifically shows 1 the intermediate circuit capacitor 1a in an exploded view diagonally from above. The intermediate circuit capacitor 1a comprises a capacitor arrangement 2a with a plurality of capacitor elements 3, which can each have a wound, metallized plastic film and can therefore be designed as a film capacitor element. For example, the plastic film can consist of polypropylene or contain this material. However, the use of other materials or capacitor technologies is also conceivable. In the example shown, the capacitor arrangement 2a also includes an optional busbar arrangement 4a, with which the capacitor elements 3 are electrically connected in parallel. In addition, the intermediate circuit capacitor 1a comprises a one-piece housing 5a with a cooling channel 6a through which a heat transfer medium can flow, and with a compartment 7a, separate from the cooling channel 6a, in which the capacitor elements 3 can be accommodated. Furthermore, the housing 5a has a receptacle 8a for a power module. The housing 5a can, for example, be made of a metal, in particular aluminum.

2 shows the intermediate circuit capacitor 1a in a state in which the capacitor arrangement 2a is inserted into the compartment 7a of the housing 5a.

3 shows the intermediate circuit capacitor 1a in a state in which the capacitor arrangement 2a in the compartment 7a is cast with a casting compound 9. In particular, the capacitor elements 3 can be sealed against moisture with the casting compound 9 and thus protected from environmental influences.

4 now shows an electrical module 10a with an intermediate circuit capacitor 1a and a power module 11 in an exploded view in a state in which the power module 11 is not yet inserted into the receptacle 8a in the housing 5a. The electrical module 10a can in particular be part of a power converter and be connected to control electronics. 5 finally shows the finished electrical module 10a with the power module 11 inserted into the receptacle 8a of the one-piece housing 5a.

In this example, the power module 11 includes a large number of controllable electronic switches 12, which are electrically connected to the capacitor elements 3. Specifically, the power module 11 has a busbar arrangement 13 for this purpose, which is connected to the busbar arrangement 4a of the intermediate circuit capacitor 1a, whereby the electronic switches 12 are also electrically connected to the capacitor elements 3. The intermediate circuit capacitor 1a is intended for smoothing a direct voltage from a direct voltage source, and the power module 11 is intended for generating an alternating voltage from the direct voltage smoothed by the intermediate circuit capacitor 1a (see also in this regard 15 ).

The cooling channel 6a has a closed cross section, can be flowed through by liquid or gaseous heat transfer media and can be integrated into a cooling circuit. The capacitor elements 3 are arranged outside the cooling channel 6a.

In the example shown, the cooling channel 6a is closed off to the outside by the power module 11 or a cooling structure connected to it and projecting into the cooling channel 6a (e.g. cooling fins or cooling pins). In particular, a part of the power module 11 or a protruding cooling structure connected to it can be arranged in the cooling channel 6a.

Alternatively, it would also be conceivable for the power module 11 to be arranged in the area of the cooling channel 6a, but outside of it, in or on the housing 5a. In particular, in this case, the housing 5a can have a cooling structure (e.g. cooling fins or cooling pins) which projects into the cooling channel 6a in the area of the power module 11.

1. a) den Kühlkanal 6a abschließen kann (direkte Kühlung),
2. b) im Kühlkanal 6a angeordnet sein kann (direkte Kühlung) oder
3. c) vollständig außerhalb des Kühlkanals 6a angeordnet sein kann (indirekte Kühlung).

The power module 11 is thermally coupled to the housing 5a, with the power module 11

1. a) can close the cooling channel 6a (direct cooling),
2. b) can be arranged in the cooling channel 6a (direct cooling) or
3. c) can be arranged completely outside the cooling channel 6a (indirect cooling).

The power module 11 can thus be cooled indirectly or directly and can be in contact with the cooling medium or not.

In the example shown, the capacitor elements 3 are each designed without a housing, with the one-piece housing 5a being provided as the only housing for the capacitor elements 3 without a housing. In this way, on the one hand, a simple structure of the intermediate circuit capacitor 1a or the electrical module 10a and, on the other hand, a very good cooling effect of the capacitor elements 3 is achieved.

The shape and dimensions of the individual capacitor elements 3 and their arrangement are purely exemplary, even if the embodiment according to 1 until 5 is advantageous. The capacitor elements 3 can of course also be designed differently and they can be arranged in a different way. Depending on a corresponding busbar arrangement 4a, the capacitor elements 3 can also be installed rotated as desired. This means that almost any shape of intermediate circuit capacitor 1a can be realized.

The 6 until 8th now show a second example of an intermediate circuit capacitor 1b in various stages of a manufacturing process and correspond to the 1 until 3 . Specifically, shows 6 the intermediate circuit capacitor 1 b in an exploded view diagonally from above. It is clearly visible that the housing 5b in this case has several compartments 7b in which the capacitor elements 3 are arranged. 7 shows the intermediate circuit capacitor 1b in a state in which the capacitor arrangement 2b is inserted into the compartments 7b of the housing 5b, and 8th shows the intermediate circuit capacitor 1b in a state in which the capacitor arrangement 2b in the compartments 7b are cast with a casting compound 9.

The 9 shows a second example of an electrical module 10b with an intermediate circuit capacitor 1b and a power module 11 in an exploded view in a state in which the power device module 11 is not yet inserted into the receptacle 8b in the housing 5b. 10 finally shows the finished electrical module 10b with the power module 11 inserted into the receptacle 8b of the one-piece housing 5b.

11 until 13 show another example of an intermediate circuit capacitor or an electrical module. Specifically, in this example, two capacitor arrangements 2c, 2c' are provided, each of which has a plurality of capacitor elements 3, 3' and an optional busbar arrangement 4c, 4c'. Furthermore, in the in 11 until 13 In the example shown, two cooling modules 14, 14 'are provided, each of which has a base plate 15 with a cooling structure 16 arranged thereon. A power module 11 is in the 11 until 13 not explicitly shown, but present in a real electrical module or power converter and then arranged between the cooling modules 14, 14 '. This creates a power module 11 that is cooled on both sides.

11 shows the arrangement in an exploded view from diagonally above. 12 shows the arrangement in a state in which the capacitor arrangements 2c, 2c' are inserted into the compartments 7c, 7c' and the cooling modules 14, 14' are inserted into the compartment 8c. 13 finally shows the arrangement in a state in which the capacitor arrangements 2c, 2c' are cast with the casting compound 9, 9' and the cooling modules 14, 14' are closed with the plate 9".

14 additionally shows a capacitor arrangement 2d with an alternative embodiment of a busbar arrangement 4d. One of the busbars is guided around the capacitor elements 3 in the longitudinal direction. This embodiment is basically suitable for all types of intermediate circuit capacitors 1a..1c, with the embodiment according to 6 until 10 the middle bar in compartment 7b must be taken into account accordingly.

15 finally shows a schematically illustrated electric vehicle 17, comprising an electrical module 10 of the previously disclosed type (here in particular as part of an inverter), a DC voltage source 18 connected thereto (e.g. a battery or a fuel cell) and an electric motor 19 connected to the electrical module 10, which forms the electric drive of the electric vehicle 17 or is included by it. Specifically, the DC voltage source 18 is connected to the capacitor arrangement 2 or possibly the Y capacitors of the electrical module 10, and the electric motor 19 is connected to the power module 11 of the electrical module 10. The electric motor 19 is mechanically coupled to wheels 21 of the electric vehicle 17 via semi-axles 20. The capacitor arrangement 2 is designed to smooth the DC voltage received from the DC voltage source 18, and the power module 11 is designed to generate an AC voltage from the smoothed DC voltage and feed it into the electric motor 19. In particular, the electric vehicle 17 can also have a cooling circuit in which the electrical module 10, specifically its cooling channel 6, is integrated. In particular, a liquid heat transfer medium can circulate in the cooling circuit.

Finally, it is noted that the scope of protection is determined by the patent claims. However, the description and drawings must be used to interpret the claims. The features contained in the figures can be exchanged and combined with one another as desired. In particular, it is also noted that the devices shown can in reality also include more or fewer components than shown. In some cases, the devices shown or their components can also be shown out of scale and/or enlarged and/or reduced in size.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 3300239 A1 [0003]
• US 20150334875 A1 [0004]
• US 2016284472 A1 [0009]

Claims (12)

DC link capacitor (1a..1c) for an electrical module (10, 10a, 10b), comprising a plurality of capacitor elements (3, 3'), characterized by a one-piece housing (5a..5c) with a cooling channel (6a..6c), through which a heat transfer medium can flow, and with a compartment (7a..7c') separate from the cooling channel (6a..6c), in which the capacitor elements (3, 3') are arranged and cast with a casting compound (9, 9'). are. DC link capacitor (1a..1c). Claim 1 , characterized in that the capacitor elements (3, 3') are each designed without a housing and the one-piece housing (5a..5c) is provided as the only housing for the capacitor elements (3, 3') without a housing. DC link capacitor (1a..1c). Claim 1 or 2 , characterized in that the housing (5a..5c) is made of a metal. DC link capacitor (1a..1c) according to one of the Claims 1 until 3 , characterized in that the housing (5a..5c) has several compartments (7b..7c') in which the capacitor elements (3, 3') are arranged. DC link capacitor (1a..1c) according to one of the Claims 1 until 4 , characterized in that the casting compound (9, 9') seals the capacitor elements (3, 3') against moisture. DC link capacitor (1a..1c) according to one of the Claims 1 until 5 , characterized by a busbar arrangement (4a..4c'), with which the capacitor elements (3, 3') are electrically connected in parallel. Electrical module (10, 10a, 10b), in particular for use in a power converter, with an intermediate circuit capacitor (1a..1c) according to one of Claims 1 until 6 , characterized by at least one power module (11) with a plurality of controllable electronic switches (12) which are electrically connected to the capacitor elements (3, 3 '), the power module (11) being in or on the one-piece housing (5a..5c ) is arranged, wherein the intermediate circuit capacitor (1a..1c) is provided for smoothing a DC voltage of a DC voltage source (18) and wherein the power module (11) is provided for generating an AC voltage from the DC voltage smoothed by the intermediate circuit capacitor (1a..1c). Electrical module (10, 10a, 10b) according to Claim 7 , characterized in that the electronic switches (12) are connected to the capacitor elements (3, 3.) via a busbar arrangement (4a..4c') of the capacitor arrangement (2..2c') and/or a busbar arrangement (13) of the power module (11). ') are electrically connected. Electrical module (10, 10a, 10b) according to Claim 7 or 8th , characterized in that the cooling channel (6a..6c) is closed off to the outside by the power module (11) or a cooling structure (16) connected to it and projecting into the cooling channel (6a..6c). Electrical module (10, 10a, 10b) according to Claim 7 or 8th , characterized in that the power module (11) or a cooling structure (16) connected to it is arranged in the cooling channel (6a..6c). Electrical module (10, 10a, 10b) according to Claim 7 or 8th , characterized in that the power module (11) is arranged in the area of the cooling channel (6a..6c), but outside of it, in or on the housing (5a..5c). Power converter, in particular inverter, characterized in that it has an electrical module (10, 10a, 10b) according to one of the Claims 7 until 11 having.

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