CN115621041A

CN115621041A - Power electronic device

Info

Publication number: CN115621041A
Application number: CN202210809699.0A
Authority: CN
Inventors: W·基恩勒; M·洛伦兹; T·迪克汉斯
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2021-07-12
Filing date: 2022-07-11
Publication date: 2023-01-17
Also published as: DE102021207316A1

Abstract

The invention relates to a power electronic component (1), in particular an electrical transformer, comprising: at least one power module (2); at least one capacitor (3); and at least one cooling device (4) for cooling the power module (2) and/or the capacitor (3), wherein the cooling device (4) has a cooling body (5) having at least one cooling channel (6) for a liquid cooling medium for discharging heat. Provision is made for the power module (2) and the capacitor (3) to be arranged together on the same heat sink (5).

Description

Power electronic device

Technical Field

The invention relates to a power electronic component, in particular an electrical transformer, comprising: at least one power module; at least one capacitor; and at least one cooling device for cooling the power module and/or the capacitor, wherein the cooling device has a cooling body with at least one cooling channel for a liquid cooling medium for discharging heat.

Background

It is known from the prior art to use power electronics, such as drive converters or transformers, with so-called intermediate circuit capacitors, which are used to smooth the voltage. These capacitors are usually cast in order to ensure electrical safety, in particular in order to comply with legally predefined air and electrical gaps, and in order to ensure dielectric protection with respect to air humidity over the entire service life of the capacitor. The current flowing in the capacitor and the components associated with the capacitor generates heat losses. It is known from the prior art to conduct this lost heat to the heat sink in a controlled manner: the capacitor is assembled on the cooling plate, for example, by means of a thermally conductive paste or paste.

Disclosure of Invention

The power electronic component according to the invention having the features of claim 1 is characterized in that the power module and the capacitor are arranged together on the same heat sink. The power module has, in particular, a connection structure for a plurality of power semiconductors or semiconductor components for converting electrical energy, in particular so-called IGBTs (insulated-gate bipolar transistors), which are arranged in a common housing or at least as a structural unit. During the conversion process, the power module also radiates waste heat. By the arrangement according to the invention of the power module and the capacitor at the heat sink, an advantageous possibility is thus provided, namely: only one cooling device is used to cool both the power modules and the capacitors as required. The capacitor and the power module are preferably integrated into the housing together with the cooling device, so that they together form an advantageous structural unit. Thus, not only is the cooling of the capacitor advantageously further improved, but also ageing effects, such as delamination or degradation of the thermally conductive glue at the components of the capacitor, in particular at the busbars or printed circuit boards, are reduced. It is also particularly advantageous to at least greatly reduce the use of casting compound. By means of the improved cooling of the capacitors and power modules, a higher electrical power of the power electronics, in particular a higher permanent power of an electric drive associated with the power electronics, can be achieved. Likewise, temperature monitoring of the capacitor by means of a temperature sensor as a protective measure is advantageously not necessary, since, for structural reasons, sufficient cooling is ensured over the service life of the capacitor or the power electronics.

According to a preferred further development of the invention, it is provided that the capacitor is a film capacitor, a ceramic capacitor or a polymer multilayer capacitor. Such a capacitor type can be arranged particularly advantageously at the heat sink or can be integrated into the proposed structural unit.

In particular, it is preferably provided that the capacitor is arranged between two power modules, and that a cooling channel is arranged between the capacitor and in each case one of the power modules in such a way that a cooling channel is arranged in each case on two mutually opposite sides of the capacitor. Such an arrangement of the cooling channels between the power module and the capacitor, respectively, yields the following advantages: a particularly effective cooling of the assembly is ensured. In this respect, a cooling of both sides of the capacitor is ensured, wherein the same section of the cooling body or of the cooling channel on the side facing away from the capacitor cools in each case one of the power modules.

According to a preferred further development of the invention, it is provided that the capacitor and the power module are arranged adjacent to one another in a plane. The arrangement of the capacitor and the power module adjacent to one another in a plane advantageously ensures that a particularly simple geometric design of the heat sink can be achieved. The capacitor and the power module are arranged alongside one another in this respect. The capacitor and the power module together form a coherent, at least largely planar surface, in particular on their side facing the heat sink, so that they can be arranged particularly simply on the heat sink. The cooling medium in the heat sink then flows underneath the capacitor and the power module. If a plurality of capacitors and/or power modules are present, as described above, it is preferred that at least two of these components, namely one of the capacitors and one of the power modules, two of the capacitors or two of the power modules, are arranged next to one another in a plane. This also yields the advantages mentioned above.

In particular, it is preferably provided that the cooling channel has a first section assigned to the capacitor and a second section functionally and/or geometrically different from the first section and assigned to the power module. The provision of different sections in the cooling channel results in the following advantages: the cooling power of the cooling device is coordinated in a simple manner with the cooling requirements of the power module and of the capacitor. The power modules and the capacitors have in particular different heat generation and thus different cooling requirements, so that the relevant sections of the cooling channels are advantageously formed correspondingly to this.

In this case, according to a preferred development of the invention, it is provided that the first partial flow is advantageously designed, in particular with a cross section which remains the same. The provision of a first section, which is advantageously designed as a flow, advantageously ensures that the cooling medium flows through the first section without hindrance, in particular without turbulence. If the first section furthermore has a cross section which remains the same, the flow speed of the cooling medium and thus the heat dissipation are advantageously constant or at least not altered by the first section.

In particular, it is preferably provided that the second section has cooling ribs or cooling pins which project into the cooling channel and which increase the surface area of the cooling channel and form a rib structure or a pin-rib structure. By providing cooling ribs or cooling pins in the second section, the following advantages are achieved: due to the thus increased surface area of the cooling channel, the heat conduction into the cooling medium and thus the heat dissipation capacity is increased compared to the first section.

According to a preferred further development of the invention, the capacitor is formed from at least two components, which are electrically connected and are arranged at a distance from one another on the heat sink. A particularly advantageous possibility is achieved by such a multi-part construction of the capacitor, namely: the individual components of the capacitor are arranged flexibly on the heat sink and, in particular, also the cooling power or heat dissipation is increased. In this case, the heat transfer between the components or the components, respectively, is advantageously increased by the raised contact area of the components with the heat sink, so that the components rest against the heat sink, respectively, also on at least one side. In particular, it is preferred that the cooling channel also extends into the projection, or that a separate cooling channel, which also contains a cooling medium, is provided in the projection, so that the heat dissipation is advantageously increased overall. Alternatively, instead of a multi-part capacitor consisting of a plurality of components, a plurality of capacitors are used, which have the same capacitance in total.

In this case, it is particularly preferably provided that the components are arranged in recesses in the heat sink, which recesses correspond to the outer contour thereof. The arrangement of the component in the recess in the heat sink yields the following advantages, namely: each of the components also at least partially rests at its side walls against the heat sink and the heat transfer is further improved by the thus increased contact area. The following advantages also result, namely: the assembly is then also held in a form-fitting manner on the heat sink. Corresponding recesses are preferably also provided for the power module or power modules or, when a plurality of capacitors are used. Thereby yielding the same advantages.

According to a preferred further development of the invention, it is provided that the capacitor is formed, in particular cast, with the power module as a structural unit. An advantageous possibility is achieved by providing a structural unit consisting of a capacitor and a power module, namely: the capacitor is arranged together with the power module at the heat sink or is exchanged.

In this case, it is particularly preferred that a printed circuit board is arranged between the heat sink and the structural unit formed by the capacitor and the power module. The arrangement of the printed circuit board between the heat sink and the structural unit provides an advantageous possibility for producing a preassembled assembly for the components. The capacitor and the power module can therefore be arranged or can be fixed during the production process, can be cast onto the printed circuit board and can then be arranged together on the heat sink. As an alternative, the printed circuit board is arranged at the side of the capacitor and the power module facing away from the heat sink. The capacitor and the power module are preferably then arranged, in particular cast, in the heat sink and then covered with the printed circuit board, so that an advantageous additional protection against environmental influences is provided. The capacitors and the power modules are cast, in particular, together with further components of the power electronics, for example semiconductor components, and then form a structural unit with these components. Capacitors and power modules are produced, in particular, as surface-mounted components (SMDs) or as components for direct-insert assembly (through hole technology, THT), soldered to a printed circuit board, arranged by means of laser or resistance welding or provided with press-in contacts.

According to a preferred further development of the invention, it is provided that the capacitor and/or the power module is cast in the heat sink. A particularly advantageous, reliable and secure connection to the heat sink is achieved by the potting of the capacitor and/or the power module in the heat sink.

Drawings

Further preferred features and combinations of features emerge from the description given above and from the claims. The invention is explained in detail below with the aid of the figures. Therefore, the method comprises the following steps:

fig. 1 to 5 each show a different exemplary embodiment of an advantageous power electronic component in cross section.

Detailed Description

Fig. 1 to 5 each show a cross section of a power electronic component 1. The points that are common to the different embodiments shown in the figures will first be described below. The same type of components are provided with the same reference numerals here.

The power electronics 1 is designed in particular as an electrical transformer and has at least one power module 2, at least one capacitor 3 and at least one cooling device 4 for cooling the power module 2 and the capacitor 3.

The cooling device 4 is arranged below the capacitor 3 and the printed circuit board 4. The cooling device 4 has a cooling body 5 with cooling channels 6 for a liquid cooling medium, in particular water or a water-glycol mixture. The power module 2 and the capacitor 3 are arranged together at a heat sink 5.

The cooling channel 6 extends completely here both below the power module 2 and below the capacitor 3. The cooling channel 6 has a first section 7 assigned to the capacitor 3 and a second section 8 assigned to the power module 2, which is functionally and geometrically different from the first section 7. Preferably, the cooling channel 6 has a rectangular cross section with a height and a depth and in particular a depth at least corresponding to the depth of the power module 2 and/or the capacitor 3. The cross section of the first section 7 of the cooling channel 6 is designed in particular such that it can be produced mechanically easily and generates as little pressure drop (little turbulence) as possible. The height of the cooling channel 6 in the second section 8 is then preferably designed as a function of the cooling capacity to be achieved or such that an optimum compromise exists between cooling capacity and pressure drop. Alternatively, the cooling channel 6 has a round, in particular circular, cross section.

The first section 7 differs from the second section 8 in that the first section 7 is advantageously configured to flow, in this case continuously having the same cross section, while the second section 8 has cooling ribs or cooling pins 9 projecting into the cooling channel 6 for increasing the surface area of the cooling channel 6, which ribs or pins form a rib structure or a pin-rib structure. For the sake of clarity, only one cooling rib or cooling pin each of the cooling ribs or cooling pins 9 is provided with a reference numeral in the figures.

The first section 7 precedes the second section 8 in the flow direction. The cooling medium is therefore first guided through the first section 7 below the capacitor 3 and then flows further through the lower second section 8 of the power module 2. Alternatively, the flow direction runs opposite. In any case, the first section 7 is designed for a pressure drop that is as small as possible, i.e. the flow path of the cooling medium should not be influenced or should be influenced only very little and in particular the smallest possible turbulence of the cooling medium is allowed. The heat transfer into the cooling medium is increased due to the increased surface area of the cooling channel 6 in the second section 8. As a result, heat dissipation from the power module 2 is improved compared to heat dissipation from the capacitor 3.

The cooling ribs or pins 9 are arranged regularly spaced apart in the second section 8 of the cooling channel 6, extend over the entire length of the power module 2, and extend from the upper side of the cooling channel 6 facing the power module 2 to the lower side of the cooling channel 6 facing away from the power module 2, i.e. completely fill the cooling channel. According to an alternative embodiment, which is not shown, the cooling ribs or cooling pins are arranged at irregular intervals, extend only over a part of the length of the power module 2 and/or project only partially into the cooling channel 6, pointing from the direction of the upper or lower side of the cooling channel 6. As an alternative, a combination of cooling ribs and cooling pins 9 is used, in particular in the case of correspondingly different geometric embodiments, in order, for example, to cool certain regions of the power module 2 more strongly.

In the exemplary embodiment of fig. 1 and 2, the capacitor 3 and the power module 2 are inserted into a recess 10 in the heat sink 5, which recess corresponds to the outer contour thereof, so that the side faces thereof are also surrounded by the heat sink 5. The capacitor 3 and the power module 2 are preferably cast in a cooling body 5.

The exemplary embodiment of fig. 2 is distinguished in that the heat sink 5 has a plurality of recesses 10, wherein the capacitors 3, which are formed from a plurality of individual components, are integrated into the heat sink 5. The capacitor 3 has three components arranged at a distance from one another. As an alternative, three separate capacitors 3 are involved.

Each of the components of the capacitor 3 or each of the capacitors 3 is surrounded by a thin layer of an electrically insulating potting compound 11. The casting compound 11 has a high thermal conductivity in order not to adversely affect the heat transfer to the heat sink or to minimize it.

Spacers made of a material with good thermal conductivity are formed between the individual components or capacitors 3, which spacers are formed here as components of the heat sink 5. These spacers extend all the way to the printed circuit board 12 above them, so that heat is also effectively removed from the printed circuit board 12.

The printed circuit board 12 is located here on the upper side of the capacitor 3 and of the power module 2 or on its side facing away from the heat sink 5 and is designed to conduct current between the capacitor 3 and the power module 2. Above the printed circuit board 12, a further component 13 of the power electronics is arranged, which component is in this case designed as a surface-mounted assembly.

A layer 14 of a Thermal Interface Material (TIM), for example a thermally conductive paste or a thermally conductive adhesive, is arranged at least partially between the printed circuit board 12 and the heat sink 5 in order to improve the thermal conduction between the printed circuit board 12 and the heat sink 5.

The power module 2 has a housing 15, in the interior of which a plurality of semiconductor components 16, for example IGBTs, are arranged. In the exemplary embodiment of fig. 3, the capacitor 3 is integrated into the housing 15 of the power module 2 and is cast together with the semiconductor component 16.

In contrast to the exemplary embodiment of fig. 1 and 2, the structural unit thus produced is not arranged below the printed circuit board 12 but above the printed circuit board 12, so that the printed circuit board 12 is arranged between the structural unit in question and the heat sink 5. Thus, prior to the assembly of the printed circuit board 12 at the heat sink 5, it is already possible to arrange further components 13 of the power electronics 1, which are not shown in fig. 3 and are likewise to be cooled, so that an advantageous preassembled unit results.

If no cooling of the further component 13 is required, the power module 2, in which the capacitor 3 is cast together with the semiconductor component 16, is alternatively arranged directly on the heat sink 5, as is shown in the exemplary embodiment of fig. 4.

Fig. 5 shows a further cross section of the power electronics 1. This embodiment differs from the preceding embodiment in particular in that two power modules 2 are now provided and the capacitor 3 is arranged between the two power modules 2 in a sandwich-like manner. Between the capacitor 3 and one of the power modules 2, in each case one region of the heat sink 5 with a cooling channel 6 is arranged, so that the cooling channels 6 are arranged on two mutually opposite sides of the capacitor 3. A particularly effective heat dissipation is thus ensured, since the heat is removed from the capacitor 3 by means of the two cooling channels 6. As in the exemplary embodiment of fig. 1 and 2, the capacitor 3 and the power module 2 are cast in a heat sink 5.

Around the heat sink 5, a printed circuit board arrangement 17 is arranged, on which further components of the power electronics 1, not shown, are arranged. These components, like the printed circuit board 12 in the preceding exemplary embodiment, are designed in particular for conducting a current between the capacitor 3 and the power module 2.

Fig. 5 also shows the compact design of power electronics 1, which results from the direct arrangement of power module 2 and capacitor 3 at heat sink 5 of cooling device 4. The power electronics 1 are preferably protected against environmental influences by a housing which is not shown for reasons of clarity, as described above. Such a housing is also preferred in the embodiment of fig. 1 to 4. The housing is likewise not shown there for reasons of clarity.

Claims

1. Power electronic component (1), in particular an electrical transformer, having:

at least one power module (2);

at least one capacitor (3); and

at least one cooling device (4) for cooling the power module (2) and/or the capacitor (3),

wherein the cooling device (4) has a cooling body (5) having at least one cooling channel (6) for a liquid cooling medium for discharging heat,

characterized in that the power module (2) and the capacitor (3) are arranged together at the same cooling body (5).

2. Power electronic device according to claim 1, characterized in that the capacitor (3) is a thin film capacitor, a ceramic capacitor or a polymer multilayer capacitor.

3. Power electronic device according to any of the preceding claims, characterized in that the capacitor (3) is arranged between two power modules (2) and that a cooling channel (6) is arranged between the capacitor (3) and one of the power modules, respectively, such that a cooling channel (6) is arranged on two mutually opposite sides of the capacitor (3), respectively.

4. Power electronic device according to any of the preceding claims, characterized in that the capacitor (3) and the power module (2) are arranged in a plane next to each other.

5. Power electronic device according to any one of the preceding claims, characterized in that the cooling channel (6) has a first section (7) assigned to the capacitor (3) and a second section (8) assigned to the power module (2) which differs functionally and/or geometrically from the first section (7).

6. Power electronic device according to claim 5, characterized in that the first section (7) is flow-configured, in particular with a cross section that remains the same.

7. Power electronic device according to any of claims 5 and 6, characterized in that the second section (8) has cooling ribs or cooling pins (9) projecting into the cooling channel (6) for increasing the surface area of the cooling channel (6), which cooling ribs or cooling pins constitute a rib structure or a pin-rib structure.

8. Power electronic device according to any of the preceding claims, characterized in that the capacitor (3) is built up from at least two components which are electrically connected and arranged at a distance from each other at the cooling body (5).

9. Power electronic device according to claim 8, characterized in that the components are arranged in recesses (10) in the cooling body (5) corresponding to its outer contour, respectively.

10. Power electronic device according to any of the preceding claims, characterized in that the capacitor (3) is formed, in particular cast, as a structural unit with the power module (2).

11. Power electronic device according to claim 10, characterized in that a printed circuit board (12) is arranged between the cooling body (5) and the structural unit consisting of capacitor (3) and power module (2).

12. Power electronic device according to any of the preceding claims, characterized in that the capacitor (3) and/or the power module (2) are cast in the cooling body (5).