CN116825535A

CN116825535A - DC link capacitor, electrical module and power converter

Info

Publication number: CN116825535A
Application number: CN202310315643.4A
Authority: CN
Inventors: A·尤纳托; S·伊尔格; L·塞夫
Original assignee: Valeo eAutomotive Germany GmbH
Current assignee: Valeo eAutomotive Germany GmbH
Priority date: 2022-03-28
Filing date: 2023-03-28
Publication date: 2023-09-29
Also published as: DE102022203036A1

Abstract

The invention relates to a DC link capacitor (1 a … c) for an electrical module (10, 10a, 10 b), in particular for a power converter or inverter, comprising a plurality of capacitor elements (3, 3'). Furthermore, the DC-link capacitor (1 a … c) comprises a one-piece housing (5 a … c) having a cooling channel (6 a … 6 c) through which the heat carrier can flow and having a compartment (7 a … c ') separate from the cooling channel (6 a … 6 c), the capacitor element (3, 3') being arranged in the compartment (7 a … c ') and potted with a potting material (9, 9'). The invention also relates to an electrical module (10, 10a, 10 b) with such a DC-link capacitor (1 a … c), in particular for a power converter, and to a vehicle (17) comprising such an inverter.

Description

DC link capacitor, electrical module and power converter

Technical Field

The present invention relates to a DC link capacitor for an electrical module or a power converter, preferably in the form of an inverter, an electrical module having such a DC link capacitor, a power converter having such an electrical module and an electric vehicle having such a power converter.

Background

DC link capacitors, electrical modules, power converters and electric vehicles of the type mentioned at the outset are known in principle from the prior art. The problem in this case is the high current flowing into and out of the DC link capacitor and the relatively strong heating of the DC link capacitor associated with the high power density.

In this respect, EP3300239A1 also discloses an arrangement comprising a power converter with a power module arranged on a metal plate, and a capacitor module comprising a capacitor element and a busbar for connecting the capacitor element to the power module. In addition, the device includes a cooling channel sandwiched between the power module and the capacitor module.

US2015/0334875A1 also discloses a cooling plate for use with an inverter of an electric vehicle. The cooling plate includes a pocket configured to receive a DC link capacitor.

However, there is a lack of a simple and effective option to properly cool the DC link capacitor.

Disclosure of Invention

It is therefore an object of the present invention to provide an improved DC link capacitor, an improved electrical module, an improved power converter and an improved vehicle with such a power converter. In particular, the object is to specify a simple and efficient choice for cooling the DC-link capacitor.

The object of the invention is achieved by a DC link capacitor for an electrical module or for a power converter, in particular an inverter, comprising a plurality of capacitor elements (with two electrodes and an interposed dielectric), each of which may have a wound metallized plastic film and thus may be implemented as a film capacitor element. Further, the DC link capacitor includes a one-piece housing having a cooling channel through which a heat carrier can flow and a compartment that is separate from the cooling channel, and the capacitor element is disposed in the compartment and potted with a potting compound. That is, the capacitor element is arranged outside the cooling passage. In particular, the cooling channel has a closed cross section through which a liquid or gaseous heat carrier can flow and which can be integrated into the cooling circuit.

As described above, the capacitor element may be in the form of, for example, a film capacitor element. For example, the plastic film may be composed of polypropylene or comprise such a material. However, the use of other materials or capacitor technologies is also conceivable. For example, a structure like that in US2016/284472A1 is conceivable. The technology is based on a prismatic monolithic polymer capacitor structure that operates at temperatures above 140 ℃ and includes a plurality of nested radiation-cured dielectric polymer layers and metal layers.

The object of the invention is also achieved by an electrical module, in particular for a power converter, comprising a DC-link capacitor of the aforementioned type and at least one power module having a plurality of controllable electronic circuits electrically connected to the capacitor element, which power module is arranged in or on a one-piece housing. In this case, a DC link capacitor is provided for smoothing the DC voltage of the DC voltage source, and a power module is provided for generating an AC voltage from the DC voltage smoothed by the DC link capacitor.

Furthermore, the object of the invention is achieved by a power converter, in particular an inverter, having an electrical module of the aforementioned type.

Finally, the object of the invention is achieved by an electric vehicle comprising an inverter of the aforementioned type, a DC voltage source connected to the DC link capacitor and an electric drive connected to the power component, wherein the electric drive is mechanically coupled to the wheels of the electric vehicle.

The proposed measures allow a simple production of the DC-link capacitor. At the same time, the proposed arrangement has excellent cooling properties. Thus, the DC link capacitor, the electrical module and the power converter may be implemented with a high power density, without the current flowing therein causing the DC link capacitor to overheat. Furthermore, the service life of such DC link capacitors is significantly increased. The capacitor element may also be more compact in size (i.e., have smaller safety tolerances) due to little or no change in operating conditions.

Further advantageous refinements and improvements of the invention can be found in the dependent claims and the description considered in connection with the figures.

Advantageously, each capacitor element is formed without a housing, and the one-piece housing is provided as the sole housing for the respective capacitor element without a housing. This firstly achieves a simple structure of the DC-link capacitor or the electrical module and secondly also a very good cooling effect of the capacitor element.

Advantageously, the housing is made of metal, in particular aluminum or an aluminum alloy. As a result, the case is easy to produce, while bringing about good heat dissipation from the capacitor element. In principle, other materials than metals for the housing are conceivable, provided that these materials have sufficient thermal conductivity and/or mechanical stability.

Advantageously, the housing has a plurality of compartments, the capacitor elements being arranged in the compartments. This may enable improved thermal conductivity, thereby improving heat dissipation from the capacitor element and increasing the mechanical stability of the DC link capacitor.

More advantageously, the potting compound seals the capacitor element from moisture. In this way, the capacitor element is well protected from external influences.

Furthermore, it is advantageous if the DC link capacitor has a busbar arrangement, with which the capacitor elements are electrically connected in parallel. In this way a high total capacitance of the DC link capacitor can be achieved.

It is also advantageous that the electronic switch is electrically connected to the capacitor element by means of a bus bar arrangement, in particular using an extended bus bar arrangement. In this way, high currents can flow from the capacitor element to the electronic switch without excessive electrical losses occurring in the process.

Furthermore, it is advantageous if the cooling channels terminate externally by the power module or by a cooling structure (e.g. a heat sink or a cooling pin) connected to the power module and protruding into the cooling channels. This allows the power modules or the cooling structures connected thereto to be cooled particularly well, since they are cooled directly by the cooling medium, i.e. in contact with the cooling medium.

Furthermore, it is advantageous if the power module or a cooling structure (for example a heat sink or a cooling pin) connected thereto is arranged in the cooling channel. This also allows the power modules or the cooling structures connected thereto to be cooled particularly well, since they are cooled directly by the cooling medium, i.e. in this case also in contact with the cooling medium.

Furthermore, it is advantageous if the power module is arranged in the region of the cooling channel but outside the cooling channel, in or on the housing. This avoids sealing problems, since the power module is not in direct contact with the cooling medium, but is only cooled indirectly. To improve the cooling performance, the housing may have a cooling structure (e.g. a heat sink or a cooling pin) protruding into the cooling channel in the region of the power module.

In summary, the power component is thermally coupled to the housing, wherein the power module:

a) The cooling channels are terminated (direct cooling),

b) Arranged in cooling channels (direct cooling), or

c) Is arranged completely outside the cooling channel (indirect cooling).

Thus, the power module may be cooled directly or indirectly, and may or may not be in contact with a cooling medium.

The above refinements and improvements of the present invention may be combined in any desired manner.

Drawings

Exemplary embodiments of the invention are shown by way of example in the accompanying schematic drawings. In the drawings:

fig. 1 shows an exploded view of a first example of a DC link capacitor from obliquely above;

fig. 2 shows the DC link capacitor of fig. 1 in a state in which the capacitor device is inserted into a compartment of the housing;

FIG. 3 shows the DC link capacitor of FIG. 1 in a state in which the capacitor device is potted in the housing compartment using a potting compound;

fig. 4 shows an exploded view of an electrical module with the DC link capacitor of fig. 3 and with a power module from obliquely above;

FIG. 5 shows the electrical module of FIG. 4 in a completed state;

fig. 6 shows an exploded view of a second example of a DC link capacitor with two receiving compartments from obliquely above;

fig. 7 shows the DC link capacitor of fig. 6 in a state in which the capacitor device is inserted into a compartment of the housing;

fig. 8 shows the DC link capacitor of fig. 6 in a state in which the capacitor device is potted in the housing compartment using a potting compound;

fig. 9 shows an exploded view of an electrical module with the DC link capacitor of fig. 8 and with a power module from obliquely above;

FIG. 10 shows the electrical module of FIG. 9 in a completed state;

fig. 11 shows an exploded view of a device with two capacitor devices and two cooling modules from obliquely above;

FIG. 12 shows the device of FIG. 11 in a state in which the capacitor device and cooling module are inserted into the associated housing compartment;

FIG. 13 shows the device of FIG. 12 in a state in which the capacitor device and cooling module are potted with a potting compound;

FIG. 14 illustrates a capacitor device having an alternative embodiment of a bus bar arrangement; and

fig. 15 shows a schematically depicted motor vehicle with a power converter of the proposed type.

Detailed Description

It should be noted in this regard that like components in different embodiments have the same reference numerals or the same component names, and in some cases have different reference numerals. The disclosure of the component contained in the specification may be correspondingly transferred to another component having the same reference numeral or the same component name. Furthermore, the position data selected in the description, such as "top", "bottom", "rear", "front", "side", etc., are related to the diagrams described and illustrated directly, and should be transferred to a new position accordingly in the case of a change in position.

Fig. 1 to 3 show a first example of a DC link capacitor 1a in various stages of the production process. Specifically, fig. 1 shows an exploded view of the DC link capacitor 1a from obliquely above. The DC link capacitor 1a comprises a capacitor device 2a having a plurality of capacitor elements 3, each capacitor element 3 may have a rolled metallized plastic film, and thus each capacitor element may be in the form of a film capacitor element. For example, the plastic film may be composed of polypropylene or comprise such a material. However, other materials or capacitor techniques are also possible. In the example shown, the capacitor device 2a further comprises an optional busbar arrangement 4a, with which busbar arrangement 4a the capacitor element 3 is electrically connected in parallel. Furthermore, the DC link capacitor 1a comprises a one-piece housing 5a having a cooling channel 6a through which the heat carrier can flow and having a compartment 7a separated from the cooling channel 6a, the capacitor element 3 being receivable in the compartment 7 a. In addition, the housing 5a has a socket 8a for a power module. For example, the housing 5a may be made of metal, in particular aluminum.

Fig. 2 shows the DC link capacitor 1a in a state in which the capacitor device 2a is inserted into the compartment 7a of the housing 5 a.

Fig. 3 shows the DC link capacitor 1a in a state in which the capacitor device 2a is potted in the compartment 7a using the potting compound 9. In particular, the capacitor element 3 can be sealed from moisture using the potting compound 9 and can therefore be protected from environmental influences.

Fig. 4 now shows in an exploded view the electrical module 10a with the DC link capacitor 1a and the power module 11 in a state in which the power module 11 has not yet been inserted into the socket 8a in the housing 5 a. In particular, the electrical module 10a may be part of a power converter and may be connected to control electronics. Fig. 5 finally shows the completed electrical module 10a, wherein the power module 11 is inserted into the socket 8a of the one-piece housing 5 a.

In this example, the power module 11 comprises a plurality of controllable electronic switches 12, which are electrically connected to the capacitor element 3. In particular, the power module 11 has for this purpose a busbar arrangement 13, which busbar arrangement 13 is connected to the busbar arrangement 4a of the DC-link capacitor 1a, whereby the electronic switch 12 is also electrically connected to the capacitor element 3. The DC link capacitor 1a is provided for smoothing the DC voltage of the DC voltage source and the power module 11 is provided for generating an AC voltage from the DC voltage smoothed by the DC link capacitor 1a (in addition to this, see also fig. 15 in this respect).

The cooling channel 6a has a closed cross section through which a liquid or gaseous heat carrier can flow and can be integrated into a cooling circuit. The capacitor element 3 is arranged outside the cooling channel 6 a.

In the example shown, the cooling channel 6a ends outside by the power module 11 or by a cooling structure (e.g. a heat sink or a cooling pin) connected to the power module 11 and protruding into the cooling channel 6 a. In particular, a part of the power module 11 or a protruding cooling structure connected thereto may thus be arranged in the cooling channel 6 a.

Alternatively, it is also conceivable to arrange the power module 11 in the region of the cooling channel 6a, but outside the cooling channel 6a in or on the housing 5 a. In particular, in this case, the housing 5a may have a cooling structure (e.g. a heat sink or a cooling pin) protruding into the cooling channel 6a in the region of the power module 11.

Thus, the power module 11 is thermally coupled to the housing 5a, wherein the power module 11:

a) The cooling channels 6a can be terminated (direct cooling),

b) Can be arranged in the cooling channel 6a (direct cooling), or

c) Can be arranged entirely outside the cooling channel 6a (indirect cooling).

Thus, the power module 11 may be cooled directly or indirectly, and may or may not be in contact with a cooling medium.

Furthermore, in the example shown, the capacitor elements 3 are formed without a housing in each case, wherein the one-piece housing 5a is provided as the sole housing for the respective capacitor element 3 without a housing. This firstly achieves a simple structure of the DC-link capacitor 1a or of the electrical module 10a and secondly also a very good cooling effect of the capacitor element 3.

Even though the embodiments according to fig. 1 to 5 are advantageous, the shape and size of the individual capacitor elements 3 and their arrangement are merely exemplary. Naturally, the capacitor elements 3 may also be formed differently, and they may be arranged differently. The capacitor element 3 can also be mounted in any desired rotation, depending on the appropriate busbar arrangement 4 a. As a result, almost any desired shape of the DC link capacitor 1a can be realized.

Fig. 6 to 8 now show a second example of a DC-link capacitor 1b in various stages of the production process and correspond to fig. 1 to 3. Specifically, fig. 6 shows an exploded view of the DC link capacitor 1b from obliquely above. It is obvious that in this case the housing 5b has a plurality of compartments 7b, the capacitor element 3 being arranged in the compartments 7 b. Fig. 7 shows the DC link capacitor 1b in a state in which the capacitor device 2b has been inserted into the compartment 7b of the housing 5b, and fig. 8 shows the DC link capacitor 1b in a state in which the capacitor device 2b in the compartment 7b has been potted with the potting compound 9.

Fig. 9 shows a second example of an electrical module 10b with a DC link capacitor 1b and a power module 11 in an exploded view, in a state in which the power module 11 has not been inserted into the socket 8b in the housing 5 b. Fig. 10 finally shows the completed electrical module 10b, wherein the power module 11 is inserted into the socket 8b of the one-piece housing 5 b.

Fig. 11 to 13 show another example of a DC link capacitor or an electrical module. Specifically, in this example two capacitor arrangements 2c, 2c ' are provided, each having a plurality of capacitor elements 3, 3', and each having an optional busbar arrangement 4c, 4c '. Furthermore, in the example shown in fig. 11 to 13, two cooling modules 14, 14' are provided, each having a base plate 15 on which a cooling structure 16 is arranged. Although the power module 11 is not explicitly shown in fig. 11 to 13, it is present in a real electrical module or power converter and is arranged in this case between the cooling modules 14, 14'. Thus, a two-sided cooled power module 11 is created.

Fig. 11 shows an exploded view of the device from obliquely above. Fig. 12 shows the arrangement in a state in which the capacitor arrangement 2c, 2c ' has been inserted into the compartment 7c, 7c ' and the cooling module 14, 14' has been inserted into the compartment 8 c. Fig. 13 finally shows the arrangement in a state in which the capacitor arrangement 2c, 2c ' has been potted with potting compound 9, 9' and the cooling modules 14, 14' have been sealed with a plate 9 ".

Fig. 14 additionally shows a capacitor device 2d with an alternative embodiment of a busbar arrangement 4 d. In this case, one of the bus bars is guided around the capacitor element 3 in the longitudinal direction. In principle this embodiment is applicable to all types of DC-link capacitors 1a … c, in the embodiment according to fig. 6 to 10 the centre network in the compartment 7b needs to be considered appropriately.

Fig. 15 finally shows a schematically illustrated electric vehicle 17, comprising an electric module 10 of the above-described type (in this case in particular as part of an inverter), a DC voltage source 18 (for example a battery or a fuel cell) connected thereto, and an electric motor 19 connected to the electric module 10, which electric motor 19 forms or is contained by an electric drive of the electric vehicle 17. In particular, the DC voltage source 18 is connected to the capacitor arrangement 2 or optionally the Y capacitor 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 by a split shaft 20. The capacitor arrangement 2 is formed 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 to feed said AC voltage to the electric motor 19. In particular, the electric vehicle 17 may also have a cooling circuit, which includes the electrical module 10, in particular the cooling channel 6 thereof. In particular, the liquid heat carrier can circulate in the cooling circuit.

In summary, the scope of protection is determined by the patent claims. The specification and drawings, however, should be used to interpret the claims. The features contained in the figures may be interchanged and combined in any desired manner. In particular, it is also clear that the shown device may in fact also comprise more or fewer components than shown. In some cases, the illustrated devices or components thereof may also not be shown to scale and/or may be increased in size and/or decreased in size.

Claims

1. A DC link capacitor (1 a..1c) for an electrical module (10, 10a, 10 b) comprising a plurality of capacitor elements (3, 3'),

it is characterized in that the method comprises the steps of,

a one-piece housing (5 a … c) having a cooling channel (6 a … 6 c) through which a heat carrier can flow and having a compartment (7 a … c ') separate from the cooling channel (6 a … 6 c), the capacitor element (3, 3') being arranged in the compartment (7 a … 7c ') and being encapsulated with an encapsulating material (9, 9').

2. The DC-link capacitor (1 a … 1 c) according to claim 1, characterized in that each capacitor element (3, 3 ') is formed without a housing and that the one-piece housing (5 a … 5 c) is provided as the sole housing for the respective capacitor element (3, 3') without a housing.

3. The DC link capacitor (1 a … c) according to claim 1 or 2, characterized in that the housing (5 a … c) is made of metal.

4. A DC link capacitor (1 a … c) according to any one of claims 1 to 3, characterized in that the housing (5 a … c) has a plurality of compartments (7 b … 7c '), the capacitor elements (3, 3 ') being arranged in the plurality of compartments (7 b … c ').

5. The DC link capacitor (1 a … 1 c) according to any one of claims 1 to 4, characterized in that the potting compound (9, 9 ') seals the capacitor element (3, 3') from moisture.

6. DC-link capacitor (1 a … 1 c) according to any one of claims 1 to 5, characterized by a busbar arrangement (4 a … c '), with which the capacitor element (3, 3') is electrically connected in parallel.

7. An electrical module (10, 10a, 10 b), in particular for use in a power converter, comprising a DC-link capacitor (1 a … c) according to any one of claims 1 to 6, characterized in that at least one power module (11) has a plurality of controllable electronic switches (12) electrically connected to the capacitor elements (3, 3'), the power module (11) being arranged in or on the one-piece housing (5 a … c), wherein the DC-link capacitor (1 a … 1 c) is provided for smoothing the DC voltage of the DC-voltage source (18) and the power module (11) is provided for generating an AC voltage from the DC voltage smoothed by the DC-link capacitor (1 a … 1 c).

8. The electrical module (10, 10a, 10 b) according to claim 7, characterized in that the electronic switch (12) is electrically connected to the capacitor element (3, 3 ') via a busbar arrangement (4 a … c ') of the capacitor arrangement (2 … c ') and/or a busbar arrangement (13) of the power module (11).

9. The electrical module (10, 10a, 10 b) according to claim 7 or 8, characterized in that the cooling channel (6 a … c) ends outside through the power module (11) or through a cooling structure (16) connected to the power module and protruding into the cooling channel (6 a … c).

10. The electrical module (10, 10a, 10 b) according to claim 7 or 8, characterized in that the power module (11) or a cooling structure (16) connected with the power module (11) is arranged in the cooling channel (6 a … c).

11. The electrical module (10, 10a, 10 b) according to claim 7 or 8, characterized in that the power module (11) is arranged in the region of the cooling channel (6 a … c), but outside the cooling channel, in or on the housing (5 a … c).

12. Power converter, in particular inverter, characterized in that the power converter has an electrical module (10, 10a, 10 b) according to any one of claims 7 to 11.