DE102023132878A1 - Inverter module and inverter - Google Patents

Abstract

The invention relates to an inverter module (10) for a modular multi-stage inverter (30) comprising a first set of semiconductor components (14), a second set of semiconductor components (16), and at least one heat sink (12), wherein the semiconductor components (14, 16) of the first set and of the second set have different power losses in an operating state of the inverter (30), characterized in that at least some of the semiconductor components (14) of the first set and at least some of the semiconductor components (16) of the second set are arranged at a first distance (32) from one another on the heat sink (12), and at least some of the semiconductor components (14, 16) of the same set are arranged at a second distance (34, 36, 38) from one another, wherein the second distance (34, 36, 38) is greater than the first distance (32). The invention provides an inverter module (10) in which heat dissipation is improved.

Description

The present disclosure relates to an inverter module and an inverter.

In electric vehicles, modular multi-level inverters can be used to convert the direct current supplied by the batteries into a variable-frequency alternating current for operating electric motors. The inverters can also be used to rectify voltages generated by the regenerative operation of the electric motors in order to feed energy into the batteries. Modular multi-level inverters have modules in which semiconductor chips are installed. The semiconductor chips in the modules are subjected to different loads, particularly at different electric motor speeds. This leads to different heating, both in terms of the operating point and the duration and intensity of the heating. The heat is dissipated using a coolant. Heat dissipation should be as efficient as possible.

Out of DE 10 2008 000 452 T5 An arrangement of switching elements on substrates is known in which the switching elements that generate the most heat are placed at different positions on the substrates. These positions are chosen so that they are spaced apart from each other on the respective substrates.

The object of the invention is to provide an inverter module and a modular multi-level inverter in which heat dissipation is further improved.

The problem is solved by the features of the independent claims. Advantageous further developments are the subject of the dependent claims and the following description.

According to a first aspect, an inverter module for a modular multi-level inverter is proposed. The inverter comprises a first set of semiconductor components, a second set of semiconductor components, and at least one heat sink, wherein the semiconductor components of the first set and the second set have different power losses in an operating state of the inverter. At least some of the semiconductor components of the first set and at least some of the semiconductor components of the second set are arranged at a first distance from one another on the heat sink, and at least some of the semiconductor components of the same set are arranged at a second distance from one another, wherein the second distance is greater than the first distance.

The core of the invention is to arrange the semiconductor components on the heat sink such that their different power losses optimize the thermal behavior of the inverter module. The semiconductor components can be arranged in a matrix-like manner on the heat sink. Furthermore, they can be divided into different sets, wherein the semiconductor components of a first set and the semiconductor components of a second set have different power losses. For this purpose, the semiconductor components of the first set can, for example, have a first power loss, and the semiconductor elements of the second set can, for example, have a second power loss. The power losses of the semiconductor components of a set can differ from one another within a fault tolerance and therefore be essentially the same. To optimize the thermal behavior of the inverter module, at least some of the semiconductor components that have the same or essentially the same power losses are arranged further apart than at least some of the semiconductor components that have different power losses. In the latter case, semiconductor components are automatically arranged next to one another or at least at the first distance from one another, in which one semiconductor component has a higher power loss than the other. Due to the heat spreading that occurs during heat conduction to the heat sink, the heat can be distributed more evenly across the heat sink than in a case where the power dissipation of semiconductor components arranged at the first distance from each other is similar or the same. The same effect is achieved by arranging semiconductor components with the same or similar power dissipation at a second distance from each other that is greater than the first distance. The semiconductor components are then further apart than semiconductor components arranged at the first distance from each other. This allows, for example, semiconductor components with high power dissipation to be arranged at the second distance from each other, minimizing the overlap between the areas in which the semiconductor components dissipate heat energy into the heat sink.

This makes it possible to provide an inverter module with improved heat dissipation. This means that the semiconductor components can be coupled to the heat sink with comparatively small surfaces, thus saving material. Alternatively or additionally, the number of semiconductor components per unit area can be increased to increase the power density. The improved heat dissipation can further extend the lifetime of the semiconductors. components can be increased. Alternatively or additionally, cooling requirements can be reduced because heat dissipation has been improved.

The heat sink can have a substrate on which the semiconductor components can be attached or formed. The substrate can have two side surfaces between which the substrate extends. The semiconductor components can be arranged on one of the side surfaces. The other side surface can be connected to a cooling element, which can, for example, have cooling channels for coolant. The power loss of the semiconductor components can be conducted through the substrate to the cooling element. The heat conducted in this way has a spread in the heat flow direction, which can be referred to as heat spread. The heat spread characterizes the area that is heated by the semiconductor component due to the power loss and through which the largest part of the heat dissipated by the semiconductor component towards the heat sink flows.

In some embodiments, the semiconductor devices of the same set have the greatest possible distance from each other on the heat sink.

The largest possible spacing may, for example, be the second spacing. Thus, at least some semiconductor devices of the same set may be arranged at different edges of an array of semiconductor devices. The edges of the array may, for example, be positioned at an edge of the heat sink. Since the edges define the available area in which the semiconductor devices can be arranged, this provides the largest possible spacing between the semiconductor devices. In particular, those semiconductor devices with the highest power dissipation may be arranged at the edges.

Furthermore, it is conceivable, for example, that the semiconductor components of the first set and the semiconductor components of the second set can be arranged at a first average distance from one another on the heat sink and semiconductor components of the same set can be arranged at a second average distance from one another, wherein the second average distance is greater than the first average distance.

If the semiconductor components of the same set are, on average, further apart than semiconductor components of different sets, a more even distribution of the power dissipation can be achieved at different power dissipations. This can further improve heat dissipation.

In a first alternative, the distances explained above can be considered only between directly adjacent semiconductor components. In a second alternative, the distances from each semiconductor component to every other semiconductor component of the inverter module can be considered to determine an average distance.

In some embodiments, at least one semiconductor component of the first and/or second set has a contact area to the heat sink that has a different size than the contact areas of the other semiconductor components of the first and/or second set.

The contact area can be essentially determined by the area of the semiconductor component. If the semiconductor component is formed as a semiconductor chip, the contact area can essentially be determined by the chip area that is in contact with the heat sink or the substrate.

The size of the contact surfaces can influence the heat dissipation to the heat sink. For example, a smaller contact surface can result in a lower heat flow between the semiconductor component and the heat sink. Similarly, a larger contact surface can result in a greater heat flow from the semiconductor components to the heat sink, even with the same thermal output.

Furthermore, it is conceivable, for example, that the first set can have a different number of semiconductor components than the second set.

For example, in a set whose semiconductor components have greater power dissipation than semiconductor components in another set, there may be fewer semiconductor components than in the other set. However, this depends on the specific requirements of the inverter module. The ratio can also be reversed. Furthermore, all sets can contain the same number of semiconductor components.

The heat sink may, for example, have at least two cooling channels which may extend through the heat sink in a flow direction of a coolant, wherein at least one semiconductor component of the first set and one semiconductor component of the second set may be arranged next to one another at the first distance transversely to the flow direction.

The coolant can flow through all of the heat sink's cooling channels in a common flow direction. This allows for high cooling performance at one end of the heat sink because the coolant has not yet dissipated heat. At another end of the heat sink, when the coolant has already passed through the heat sink and absorbed heat, the cooling performance may be lower. The semiconductor components of the same set can be spaced as far apart as possible on the heat sink, at least transversely to a coolant flow direction in the heat sink. This allows semiconductor components of the same set to transfer heat to different cooling channels, so that the coolant is heated evenly in all cooling channels.

According to a further example, it is conceivable that the semiconductor components of the first set can be of the same type and/or that the semiconductor components of the second set can be of the same type.

Alternatively, it can be provided that various semiconductor components can be combined in the first set. Only the power dissipation of the semiconductor components in the first set can be essentially the same or similar. The same can apply to the second set.

The inverter module may, for example, comprise a third set of semiconductor components, the semiconductor components of which may have lower power losses in an operating state of the inverter than the semiconductor components of the first set and the second set.

The semiconductor components of the third set can also be heated, for example, primarily by the power dissipation of the neighboring semiconductor components. Furthermore, the semiconductor components of the third set can be arranged on the heat sink, for example, as spacers between two semiconductor components of another set, in particular transversely to a flow direction of a coolant in the heat sink. It goes without saying that the neighboring semiconductor components can also belong to different sets.

Furthermore, it is conceivable, for example, that the semiconductor components of the third set can be arranged in a flow direction of a coolant in the heat sink between semiconductor components of the first and/or second set.

In particular, when coolant flows through the heat sink, a semiconductor component of the third set can be arranged on the heat sink between two semiconductor components of another set in the direction of coolant flow. It goes without saying that the adjacent semiconductor components can also belong to different sets.

In some embodiments, the semiconductor components are formed as semiconductor chips.

According to a second aspect, a modular multi-stage inverter having at least two inverter modules is proposed, wherein at least one of the inverter modules is designed according to the first aspect.

The advantages and effects, as well as further developments, of the inverter are derived from the advantages and effects, as well as further developments of the inverter module described above. To avoid repetition, reference is made to the previous description in this regard.

According to a third aspect, a vehicle is proposed. The vehicle comprises at least one electrical energy storage device, an electric motor, and at least one inverter module according to the preceding description or at least one modular multi-stage inverter according to the preceding description, wherein the inverter module or the inverter electrically connects the electrical energy storage device to the electric motor.

The advantages and effects, as well as further developments, of the vehicle are derived from the advantages and effects, as well as further developments, of the inverter module described above. To avoid repetition, reference is made to the previous description in this regard.

• 1 eine schematische Darstellung eines Wechselrichtermoduls;
• 2a, b eine schematische Querschnittsdarstellung eines Wechselrichtermoduls;
• 3 eine schematische Darstellung eines Schaltkreises eines Wechselrichtermoduls;
• 4 eine schematische Darstellung der Schaltung eines Wechselrichtermoduls; und
• 5 eine schematische Darstellung eines Fahrzeugs.

The invention is described below using an exemplary embodiment with the aid of the accompanying drawings. They show:

• 1 a schematic representation of an inverter module;
• 2a , b a schematic cross-sectional view of an inverter module;
• 3 a schematic diagram of a circuit of an inverter module;
• 4 a schematic diagram of the circuit of an inverter module; and
• 5 a schematic representation of a vehicle.

The inverter module is described below in accordance with 1 designated in its entirety by the reference number 10.

The inverter module 10 has a heat sink 12 on which several sets of semiconductor components 14, 16, 18 are arranged. At least a first set of semiconductor components 14 and a second set of semiconductor components 16 are present. In this example, a third set of semiconductor components 18 is also present.

In this example, the semiconductor components 14 of the first set have higher power dissipation than the semiconductor components 16 of the second set. The semiconductor components 18 of the third set may have lower power dissipation than the semiconductor components 16 of the second set and may be heated primarily by the heat from the adjacent semiconductor components 14, 16 of the first and second sets.

A coolant can flow through the heat sink 12 in a flow direction 50. The coolant has its coldest temperature upon entering the heat sink 12. As it flows through the heat sink 12, the coolant is heated by the power dissipation of the semiconductor components 14, 16, so that the cooling performance in the flow direction 50 is reduced.

The semiconductor components 14 of the first set and the semiconductor components 16 of the second set can be arranged at a first distance 32 from one another to optimize the cooling performance on the heat sink 12. In the example shown according to 1 The first distance 32 can be determined transversely to the flow direction 50 of the coolant. Semiconductor components 14, 16 of the same set can have a second distance 34, 36, 38 from one another. The second distance 34, 36, 38 is greater than the first distance 32.

In the example shown according to 1 The majority of the semiconductor components 14 of the first set have a second distance 34, 36, 38 from the other semiconductor components 14 of the first set that is greater than the first distance 32. Only a small portion of the distances between the semiconductor components 14 of the first set are less than or equal to the first distance 32.

In particular, however, in this example, transverse to the flow direction 50, all second distances 38 are greater than the first distances 32.

Furthermore, an average first distance, which is calculated from the sum of all first distances 32 in all directions between different semiconductor components 14, 16 of the first and second set divided by the number of first distances 32, can also be smaller than an average second distance, which is calculated from the sum of all second distances 34, 36, 38 in all directions between identical semiconductor components 14 of the first set or between identical semiconductor components 16 of the second set divided by the number of second distances 34, 36, 38.

The semiconductor components 16 of the second set are arranged between the semiconductor components 14 of the first set, transverse to the flow direction 50. Furthermore, the semiconductor components 14 of the first set are arranged transverse to the flow direction 50 at the edges of the heat sink 12.

This allows the power loss of the semiconductor components 14 to be optimally distributed over the heat sink 12 without excessively heated areas being created by overlaps of sections of the heat sink 12 heated by the semiconductor components.

The distribution of the power loss of the semiconductor components 14, 16 of the first set or the second set can be further improved by arranging the semiconductor components 18 of the third set between similar semiconductor components 14, 16 in the flow direction 50. In particular, in the region of the heat sink 12 in which the coolant has already absorbed heat from the semiconductor components 14, 16 as it flows through the heat sink 12, the semiconductor components 18 of the third set can act as spacers in order to optimally distribute the power loss of the adjacent semiconductor components 14, 16.

In this example, in the flow direction 50, a row of semiconductor components 18 of the third set is provided transversely to the flow direction 50 as the penultimate row in the arrangement of the semiconductor components 14, 16, 18.

Several cooling channels 24 through which the coolant can flow can be formed in the heat sink 12. These are shown in cross section in the 2a and 2b shown. In this example, the heat sink 12 has a total of four cooling channels 24 that extend parallel in the flow direction 50 through the heat sink 12. The heat sink 12 can have a cooling element 22 in which the cooling channels 24 are formed. Furthermore, the heat sink 12 can have a substrate 20 that is arranged between the semiconductor components 14, 16, 18 and the cooling element 22. The semiconductor components 14, 16, 18 are arranged on one side of the substrate 20, and the cooling element 22 is arranged on an opposite side of the substrate 20.

Furthermore, the semiconductor components 14, 16, 18 have contact surfaces 46, 48, with which they are connected to the substrate 20. The power loss of the semiconductor components 14, 16, 18 is transferred to the substrate 20 via the contact surfaces 46, 48. From the substrate 20, the heat is further conducted to the cooling element 22 and the cooling channels 24.

The power loss of the semiconductor components 14, 16, 18 is therefore conducted through the substrate 20 to the cooling channels 24 arranged in the cooling element 22.

The contact surfaces 46, 48 of the semiconductor components 14, 16, 18 can have different sizes.

In 2a The heat spread 26 of the semiconductor components 14 of the first set is also shown schematically. The heat spread 26 indicates the areas that are heated by the power loss of the respective semiconductor component 14. It can be seen that in the example shown, one semiconductor component 14 heats the coolant in two cooling channels 24. Each semiconductor component 14 heats different cooling channels. Overlapping of the heat spread 26 of different semiconductor components 14 of the first set is avoided by the arrangement of the semiconductor components 14 on the heat sink 12.

In 2b The heat spread 28 of a semiconductor component 16 of the second set is depicted. This illustration shows that the semiconductor component 16 of the second set also dissipates heat to two cooling channels 24. Each of the two cooling channels 24 is heated by a different semiconductor element 14 of the first set or covered by its heat spread 26.

The coolant in the cooling channels 24 is therefore heated uniformly by the semiconductor components 14, 16 of the first and second sets.

In 3 An exemplary circuit with semiconductor components 14, 16, 18 is shown. The circuit is integrated into the inverter module 10. Each of the semiconductor components 14, 16, 18 can be formed, for example, as a semiconductor chip that is attached to the heat sink 12.

Any other circuit suitable for conversion in an inverter module 10 for a modular multi-level inverter may be used.

4 shows a schematic representation of a multi-stage modular inverter 30. The inverter 30 has a plurality of inverter modules 10, which can be configured according to the above explanations. At least one inverter module 10 is configured according to the above explanations. The inverter modules 10 of the inverter 30 can be interconnected.

In 5 A vehicle 40 is depicted, which may be configured as an electric vehicle. The vehicle 40 may have an energy storage device 42, which may, for example, be configured as a battery storage device.

Furthermore, the vehicle 40 may include an electric motor 44 configured to drive the vehicle 40. The electric motor 44 may also function as a generator, for example, to convert kinetic energy into electrical energy when the vehicle decelerates.

The inverter 30 or at least one inverter module 10 can form an electrical connection between the energy storage device 42 and the electric motor 44. Energy provided by the energy storage device 42 with a direct voltage can be converted into an alternating voltage by the inverter 30 or the at least one inverter module 10. The frequency of the alternating voltage can depend on the requested speed for the vehicle 40.

Furthermore, electrical energy provided by the electric motor 44 with an alternating voltage can be converted into a direct voltage by the inverter 30 or the at least one inverter module 10 and fed into the electrical energy storage device 42.

The example described above does not limit the invention in any way. Rather, the invention can be modified in many ways. All of the features of the invention described above can be essential to the invention alone or in combination with one another.

List of reference symbols

10

Inverter module

12

heat sink

14

semiconductor component

16

semiconductor component

18

semiconductor component

24

cooling channel

26

Heat spreading

30

Inverter

32

first distance

34

second distance

36

second distance

38

second distance

40

vehicle

42

electrical energy storage

44

Motor

46

Contact surface

48

Contact surface

50

Flow direction

QUOTES CONTAINED IN THE DESCRIPTION

This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This 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

• DE 10 2008 000 452 T5 [0003]

Claims (12)

Inverter module (10) for a modular multi-stage inverter (30) comprising a first set of semiconductor components (14), a second set of semiconductor components (16) and at least one heat sink (12), wherein the semiconductor components (14, 16) of the first set and of the second set have different power losses in an operating state of the inverter (30), characterized in that at least some of the semiconductor components (14) of the first set and at least some of the semiconductor components (16) of the second set are arranged at a first distance (32) from one another on the heat sink (12) and at least some of the semiconductor components (14, 16) of the same set are arranged at a second distance (34, 36, 38) from one another, wherein the second distance (34, 36, 38) is greater than the first distance (32). Inverter module (10) according to Claim 1 , characterized in that semiconductor components (14, 16) of the same set have the greatest possible distance from one another on the heat sink (12). Inverter module (10) according to Claim 1 or 2 , characterized in that the semiconductor components (14) of the first set and the semiconductor components (16) of the second set are arranged at a first average distance from one another on the heat sink (12) and semiconductor components (14, 16) of the same set are arranged at a second average distance from one another, the second average distance being greater than the first average distance. Inverter module (10) according to one of the Claims 1 until 3 , characterized in that at least one semiconductor component (14, 16) of the first and/or second set has a contact surface (46, 48) to the heat sink (12) which has a different size than the contact surfaces (46, 48) of the further semiconductor components (14, 16) of the first and/or second set. Inverter module (10) according to one of the Claims 1 until 4 , characterized in that the first set has a different number of semiconductor components (14, 16) than the second set. Inverter module (10) according to one of the Claims 1 until 5 , characterized in that the heat sink (12) has at least two cooling channels (24) which extend through the heat sink (12) in a flow direction (50) of a coolant, wherein at least one semiconductor component (14) of the first set and one semiconductor component (16) of the second set are arranged next to one another at the first distance (32) transversely to the flow direction (50). Inverter module (10) according to one of the Claims 1 until 6 , characterized in that the semiconductor components (14) of the first set are of the same type and/or that the semiconductor components (16) of the second set are of the same type. Inverter module (10) according to one of the Claims 1 until 7 , characterized in that the inverter module (10) has a third set of semiconductor components (18), the semiconductor components (18) of which have lower power losses in an operating state of the inverter (30) than the semiconductor components (14, 16) of the first set and the second set. Inverter module (10) according to Claim 8 , characterized in that the semiconductor components (18) of the third set are arranged in a flow direction (50) of a coolant in the heat sink (12) between semiconductor components (14, 16) of the first and/or second set. Inverter module (10) according to Claim 1 until 9 , characterized in that the semiconductor components (14, 16, 18) are designed as semiconductor chips. Modular multi-level inverter (30) comprising at least two inverter modules (10), wherein at least one of the inverter modules (10) is constructed according to one of the Claims 1 until 10 is trained. Vehicle (40) comprising at least one electrical energy storage device (42), an electric motor (44) and at least one inverter module (10) according to one of the Claims 1 until 10 or at least one modular multi-level inverter (30) according to Claim 11 , wherein the inverter module (10) or the inverter (30) electrically connects the electrical energy storage device (42) to the electric motor (44).

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