Power module, inverter having a power module

Abstract

The invention relates to a power module (LM), comprising: - a circuit substrate (ST) having a top face, on which a first electrical connection surface (F1), for surface-mounting first transistor switches (T1), and a second electrical connection surface (F2), for surface-mounting second transistor switches (T2), as well as third electrical connection surfaces (F3), are formed, wherein the first (F1) and the second (F2) connection surfaces are electrically insulated from one another and each extend in an extension direction (ER) of the circuit substrate (ST), and the third connection surfaces (F3) are insulated from one another and from the first (F1) and the second (F2) connection surfaces and are arranged next to one another in the extension direction and between the first (F1) and the second (F2) connection surfaces; - snubber circuits, each of which is formed, at least in part, on one of a plurality of regions (B) of the circuit substrate (ST), wherein the regions (B) each span one of the third connection surfaces (F3) and the second connection surface (F2); - wherein the snubber circuits are each electrically connected to the relevant corresponding third connection surface (F3) and the second connection surface (F2). The invention also relates to an inverter having a power module of the type stated.

Description

[0001] Description

[0002] Power module, inverter with one power module

[0003] Technical area:

[0004] The present invention relates to a power module and an inverter with said power module.

[0005] State of the art and task of the invention:

[0006] Power modules with transistor switches for converting currents or voltages and inverters with power modules, for example for providing phase currents for an electrical machine, are known and are used, among other things, in the drive systems of electrically powered motor vehicles.

[0007] The general requirement is to make the power modules more powerful and at the same time with lower power losses.

[0008] Accordingly, the object of the present application is to provide a powerful and at the same time low-loss power module.

[0009] Description of the invention:

[0010] This problem is solved by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims.

[0011] According to a first aspect of the invention, a power module for converting currents or voltages is provided, in particular for use in an inverter for providing phase currents for an electric machine of an electrically driven motor vehicle.

[0012] The power module has a circuit carrier, for example in the form of a printed circuit board or a ceramic substrate or another known comparable circuit carrier, which has a first electrical connection area for the surface mounting of first transistor switches and a second electrical connection area for the surface mounting of second transistor switches, as well as a plurality of third electrical connection areas.

[0013] The first and second connection surfaces, as well as the third connection surfaces, are designed or arranged on the same side of the circuit carrier in such a way that they are electrically insulated from one another. The first and second connection surfaces each extend along an extension direction of the circuit carrier. The third connection surfaces are electrically insulated from one another (and from the first and second connection surfaces) and are designed or arranged next to one another in the extension direction and between the first and second connection surfaces.

[0014] The connection surfaces described above are each connected electrically conductive surfaces made of a metal or a metal alloy, such as copper or a copper alloy. Depending on the application of the power module, the connection surfaces are designed to conduct currents of up to several hundred amperes, with the corresponding layer thickness and surface width of the respective connection surfaces. In particular, depending on the power module's performance requirements, the connection surfaces are designed with a correspondingly extended surface area for connecting multiple transistor switches in parallel.

[0015] The power module further comprises a plurality of snubber circuits or snubber elements, for example in the form of RC elements, which are each formed at least partially on one of a plurality of (sub-)regions of the top side of the circuit carrier, wherein the regions each partially span one of the third connection surfaces and the second connection surface. The regions each partially overlap with the respective corresponding third connection surface and the second connection surface. The regions are each composed in particular of an edge region of the third connection surface which borders on the second connection surface, an edge region of the second connection surface which borders on the third connection surface, and optionally an intermediate region which extends from the second to the third connection surface. The edge regions are in particular only a surface portion of the underlying region, for example no more than 50%, 30%, 20% or 10%. The intermediate region contains in particularAn electrically isolating structure that electrically insulates the two connection surfaces, such as a trench between the connection surfaces. "Electrically insulated" refers here to conductive features that can have different potentials. The intermediate region can also contain an electrically insulated conductor track section, which serves, in particular, as a connecting element in a snubber circuit. The snubber circuits are thus each located in a region where the second connection surface and the third connection surface adjoin one another, and in particular in a region between the circuit carrier on the one hand and a second or third power connection rail on the other.

[0016] The snubber circuits comprise both circuit components of the snubber elements, such as capacitors and resistors (in the case of RC elements), and (internal) electrical connections between these circuit components, such as conductor tracks formed on the circuit carrier, and also (external) electrical connections from the respective snubber elements to respective corresponding (external) circuit components of the power module, such as conductor tracks formed on the circuit carrier or bond connections bonded to the corresponding components. The snubber circuits are each electrically connected to the respective corresponding third connection area and the second connection area via these external electrical connections. The circuit components and the internal or external electrical connections of the respective snubber elements are at least partially, preferably mostly, in particularcompletely executed or arranged on one of the several regions of the upper side of the circuit carrier, wherein each individual region partially spans one of the third connection surfaces and the second connection surface and thus electrically connects these two connection surfaces via the shortest connection path.

[0017] Due to their functionality, the power modules generate high-frequency oscillations in currents with voltage spikes during operation. These oscillations occur when switching inductive loads, such as electrical machines, and can lead to malfunctions or even failure of the power modules or other circuits electrically connected to the power modules. These high-frequency oscillations prevent the power module from switching the transistor switches faster, thus preventing the power module from operating at high power with low power dissipation.

[0018] The source of the high-frequency oscillations in currents with voltage spikes lies in the transistor switches, which are switched on / off in a clocked manner during operation of the power module, and thus in the (closed) circuit between the positive-voltage and negative-voltage supply current connections of the power module and the respective transistor switches. In the power module described above, the two supply current connections are each formed by the second connection surface and the third connection surfaces on the same top side of the circuit carrier. If the power module is part of an inverter, the first connection surface is formed as a phase current connection of the power module.

[0019] By arranging or electrically connecting the snubber circuits as attenuators directly on the respective areas of the same top side of the circuit carrier (such as the second connection pad or the third connection pads), which partially span the second connection pad and the respective corresponding third connection pads and thus the two supply current connections (to the transistor switches), the snubber circuits are placed and electrically connected directly and with low inductance to the source of the high-frequency oscillations. This allows the snubber circuits to efficiently attenuate the high-frequency oscillations directly at their source, before they propagate via the supply current connections to other circuit components of the power module and other circuit devices connected to the power module, where they can cause interference or other damage.The short distance between the snubber circuits and the source of the high-frequency oscillations maximizes the efficiency of the snubber circuits. Accordingly, the transistor switches can be switched quickly and with low losses at a high switching speed. Consequently, a power module can be operated with high power and low losses. Furthermore, this allows the power module to use fast-switching, low-loss transistor switches.

[0020] The power module described above can be used in (power) inverters, (power) DC-DC converters, (power) converters or similar (power) electronic devices where a high switching speed with simultaneously low power loss in the transistor switches is required.

[0021] For example, the snubber circuits each have a capacitor and / or a resistor, wherein the capacitor and / or the resistor of the respective snubber circuits are each arranged on the respective corresponding area.

[0022] For example, the snubber circuits each have (at least) one bond connection, whereby the bond connection of the respective snubber circuits each spans the respective corresponding area (at least partially).

[0023] For example, the snubber circuits each have at least one conductor track connection (or conductor track sections) formed on the same upper side of the circuit carrier on which the aforementioned connection pads are formed. The conductor track connections are electrically insulated or separated from the aforementioned connection pads.

[0024] Using the aforementioned capacitors, resistors, bonded connections, and / or conductor sections, the snubber circuits can be implemented easily and cost-effectively (exclusively) using standard components in a wide variety of designs. Furthermore, the snubber circuits can be easily adapted to various requirements, such as different power requirements.

[0025] For example, the first connection area and / or the second connection area and / or the third connection areas are designed as conductor tracks that are formed on the same side of the circuit carrier.

[0026] For example, the first connection surface has first connection sections that extend transversely to the direction of extension and in the direction of the second connection surface. The first connection sections and the third connection surfaces alternate in the direction of extension or are arranged alternately with one another. Alternatively or additionally, the second connection surface has, for example, second connection sections that extend transversely to the direction of extension and in the direction of the first connection surface. In this case, the second connection sections and the third connection surfaces alternate in the direction of extension or are arranged alternately with one another.

[0027] The power module further comprises, for example, a plurality of first transistor switches that are surface-mounted on the first connection pad and are each electrically connected to a respective corresponding third connection pad via a bond connection. One, two, or more first transistor switches can be electrically connected to the same corresponding third connection pad.

[0028] The power module further comprises, for example, a plurality of second transistor switches which are surface-mounted on the second connection surface and are each electrically connected to the first connection surface via a bond connection.

[0029] The first transistor switches and / or the second transistor switches are formed, for example, as silicon carbide transistor switches.

[0030] Because the snubber circuits are positioned directly at the source of the high-frequency oscillations, they efficiently dampen them at the source and thus effectively prevent their subsequent damage. These snubber circuits enable fast, low-loss switching of the transistor switches. Accordingly, fast-switching, low-loss silicon carbide transistor switches can be used in the power module.

[0031] The power module further comprises, for example, a first power connection bar (in English “busbar”), which is (e.g.) comb-shaped and) has first connection lugs or connection tabs (or connection legs), via which the first power connection bar rests on the first connection surface and is electrically connected to the first connection surface. Alternatively or in addition to the first power connection bar, the power module has a second power connection bar, which (e.g.) also has a comb-shaped and) second connection lugs or connection tabs (or connection legs), via which the second power connection bar rests on the second connection surface and is electrically connected to the second connection surface. Alternatively or in addition to the first or second power connection bar, the power module has a third power connection bar, which (e.g.) also has a comb-shaped and) third connection lugs or connection tabs (orconnecting legs) via which the third power connection rail rests on the respective third connection surfaces and is electrically connected to the respective third connection surface.

[0032] In the event that the power module has the second and the third power connection rail, the second and the third power connection rail are arranged largely overlapping with each other (in particular except for the respective first connection lugs or the respective second connection lugs).

[0033] For example, the second and / or the third connection lugs each extend at least partially over one of the regions, which each partially span one of the third connection surfaces and the second connection surface.

[0034] For example, the second and / or third terminal lugs are each shaped such that an (intermediate) space is located or formed between the respective second or third terminal lugs on the one hand and the respective corresponding areas over which the respective second or third terminal lugs extend on the other hand. One of the snubber circuits is at least partially arranged or placed in each of these spaces.

[0035] The gaps allow for compact and space-saving design of the snubber circuits without requiring additional installation space, which could result in a larger dimensioning of the construction volume of the power module, in particular an increase in the construction height of the power module.

[0036] For example, the first connection surface and the second connection surface each extend along the direction of extension from a first end region of the circuit carrier to a second end region of the circuit carrier facing away from the first end region in the direction of extension. The first connection surface and the second connection surface can extend, in particular, parallel to one another.

[0037] For example, the circuit carrier has two outer strip sections facing away from one another and a central strip section between the two outer strip sections. The strip sections extend, for example, along the extension direction from the first end region of the circuit carrier to the second end region of the circuit carrier. Furthermore, the first and second connection surfaces are each formed, for example, distributed on each of the two outer strip sections, with the third connection surfaces being formed, for example, on the central strip section. For example, the first or second connection sections—depending on which of the connection sections the power module has—are also formed on the central strip section.

[0038] For example, the first connection area and the second connection area and the third connection areas as well as the above-mentioned regions are located on the same surface of the circuit carrier or are formed on the same surface of the circuit carrier.

[0039] According to a second aspect of the invention, an inverter is provided, in particular for providing phase currents for an electric machine of an electrically driven motor vehicle.

[0040] The inverter comprises at least one previously described power module, in particular for providing phase currents for an electrical machine, and a driver circuit for operating the power module, as well as a housing, wherein the power module and the driver circuit are arranged in the housing and are electrically connected to one another.

[0041] The second connection surface on the one hand and the third connection surfaces on the other hand are preferably supply potential connections (for DC voltage). The first connection surface is in particular a load connection surface. In populated power modules, the first transistor switches are connected in parallel with each other, whereby the second transistor switches are also connected in parallel with each other. The first transistors are connected in parallel, in particular by the third power connection rail or by the connection to the same third connection surface. The first transistors and the second transistors each form a half-bridge in pairs. The first transistors each form a low-side switching element of the half-bridge and the second transistors each form a high-side switching element of the half-bridge. The connection point within the half-bridge (ieThe first connection area (the connection between the first transistors on the one hand and the second transistors on the other hand) corresponds to the first connection area. The snubber circuits are located in an area where the second connection area, which corresponds to a first supply potential (connection), borders on the third connection areas, which correspond to a second supply potential (connection). The connection of the snubber circuits to the supply potentials therefore requires only very short lines. The connection of the supply potentials (via power connection rails) can be made from one side, while the opposite side can serve to connect the connection point (phase or load connection), for example by means of another power connection rail, and thus has little coupling to the supply potentials. The snubber circuits can be arranged between the power connection rails of the supply potentials and the circuit carrier.

[0042] Short description of the drawings:

[0043] In the following, exemplary embodiments of the invention are explained in more detail with reference to the accompanying drawings. In the drawings:

[0044] Figure 1 shows, in a first schematic plan view, parts of a power module according to an exemplary embodiment of the invention;

[0045] Figure 2 shows a second schematic plan view of a snubber circuit of the power module from Figure 1;

[0046] Figures 3A, 3B show two further schematic plan views of further components of the power module from Figure 1; and

[0047] Figure 4 shows a schematic cross-sectional side view of a partial section of the power module from Figure 1.

[0048] Detailed description of the drawings:

[0049] Figure 1 shows, in a first schematic plan view, parts of a power module LM according to an exemplary embodiment of the invention.

[0050] In this embodiment, the power module LM is formed as a half-bridge module of an inverter for providing phase currents for an electrical machine.

[0051] The power module LM has a circuit carrier ST in the form of a ceramic substrate, which has a first electrical connection area F1, a second electrical connection area F2, and a plurality of third electrical connection areas F3 on its upper side. The connection areas F1, F2, F3 are formed as conductor tracks on the same upper side of the circuit carrier ST, which are electrically insulated or separated from one another. The first and second connection areas F1, F2 are located on two mutually opposite, outer strip sections A1, A2 of the circuit carrier ST and each extend along an extension direction ER of the circuit carrier ST.

[0052] The first connection surface F1 has a plurality of wide-area connection sections AB which extend parallel to one another and in a prong-like (or comb-like) manner transversely to the direction of extension ER and in the direction of the second connection surface F2 and thus on a central strip section A3 of the circuit carrier ST between the two outer strip sections A1, A2. The third connection surfaces F3 are formed on the central strip section A3 and thus between the first and second connection surfaces F1, F2. The third connection surfaces F3 and the connection sections AB alternate in the direction of extension ER. The third connection surfaces F3 are electrically insulated from one another and from the first and second connection surfaces F1, F2 and thus also from the connection sections AB of the first connection surface F1.

[0053] The strip sections A1, A2, A3 extend parallel to one another and along the extension direction ER from a first end region E1 of the circuit carrier ST to a second end region E2 of the circuit carrier ST facing away from the first end region E1.

[0054] Accordingly, the first connection surface F1 and the second connection surface F2 also each extend along the extension direction ER from the first end region E1 to the second end region E2 of the circuit carrier ST and parallel to one another.

[0055] The first connection area F1 and the second connection area F2 and the third connection areas F3 as well as the areas B are located on the same surface of the circuit carrier ST and thus on the same level.

[0056] The power module LM further comprises a group of first transistor switches T1, which are surface-mounted on the first connection pad F1, placed one behind the other in the extension direction ER, and are thus electrically connected to the first connection pad F1 on the bottom side. The first transistor switches T1 are each electrically connected to one of the third connection pads F3 via a bond connection V2. The power module LM further comprises a group of second transistor switches T2, which are surface-mounted on the second connection pad F2, placed one behind the other in the extension direction ER, and are thus electrically connected to the second connection pad F2 on the bottom side. The second transistor switches T2 are each electrically connected to a corresponding connection section AB of the first connection pad F1, and thus to the first connection pad F1, via a further bond connection V3.In this embodiment, the first and second transistor switches T1, T2 are formed as fast-switching SiC transistors (SiC: “silicon carbide”).

[0057] The power module LM further comprises a group of snubber circuits or snubber elements, each of which is at least partially formed on one of a plurality of regions B of the circuit carrier ST. Regions B are located on the same surface of the circuit carrier ST as the aforementioned connection areas F1, F2, F3 and each partially span one of the third connection areas F3 and the second connection area F2. The snubber circuits are each electrically connected to the respective corresponding third connection area F3 and the second connection area F2.

[0058] Figure 2 shows, in a second schematic plan view, an exemplary embodiment of the snubber circuit of the power module LM from Figure 1.

[0059] Figure 2 shows only one of the above-mentioned snubber circuits as an example. The snubber circuit has a conductor track section L, a capacitor C, and a resistor R, which are arranged in the corresponding region B. The conductor track section L is located between two adjacent connection sections AB of the first connection surface F1, viewed in the direction of extension ER, and between the corresponding third connection surface F3 and the second connection surface F2, viewed in the direction transverse to the direction of extension ER. The conductor track section L is electrically insulated or separated from all two adjacent connection sections AB, the corresponding third connection surface F3, and the second connection surface F2.The capacitor C is located partly on the corresponding third connection surface F3 and partly on the conductor track section L, and is electrically connected to the corresponding third connection surface F3 and the conductor track section L. The capacitor C thus partially spans the corresponding third connection surface F3 and the conductor track section L. The resistor R is located partly on the conductor track section L and partly on the second connection surface F2, and is electrically connected to the conductor track section L and the second connection surface F2. The resistor R thus partially spans the conductor track section L and the second connection surface F2.The snubber circuit thus connects the respective corresponding third connection surface F3 to the second connection surface F2 and is configured to reduce high-frequency current components in the direct current of the power module LM, which flows between the third connection surfaces F3 on the one hand and the second connection surface F2 on the other hand during operation of the power module LM, and to limit voltage levels in the direct current.

[0060] Figures 3A, 3B each show, in a further schematic plan view, the previously described power module LM with further circuit components: busbars made of a metal or a metal alloy, in particular of copper or a copper alloy, which each form a phase current connection (first power connection bar P), a positive voltage side supply current connection (second power connection bar H+), or a negative voltage side supply current connection (third power connection bar H-) of the power module LM.

[0061] The three current connection rails P, H+, H- are essentially rake-shaped or comb-shaped and each have a flat, extended main part HT 1 , HT2 (see Figure 4), HT3 and on the respective main part HT 1 , HT2, HT3 prong-shaped (or comb-shaped) connection lugs (or connection tongues or connection legs) Z1 , Z2, Z3.

[0062] The first power connection rail P rests on the first connection surface F1 via its connection lugs Z1 and is electrically contacted with the first connection surface F1 in multiple ways, as illustrated in Figure 3A. The main part HT1 of the first power connection rail P extends essentially over the first connection surface F1 and parallel to the top side of the circuit carrier ST.

[0063] Analogously, the second power connection rail H+ rests on the second connection surface F2 via its connection lugs Z2 and is electrically contacted multiple times with the second connection surface F2, as illustrated in Figure 3B. The main part HT2 of the second power connection rail H+ extends substantially over the second connection surface F2 and parallel to the top side of the circuit carrier ST, as illustrated in Figure 4. The third power connection rail H- rests on the respective third connection surfaces F3 via its connection lugs Z3 and is electrically contacted with the respective third connection surfaces F3, as illustrated in Figure 3B. The main part HT3 of the third power connection rail H- also extends substantially over the second connection surface F2 and parallel to the top side of the circuit carrier ST, as illustrated in Figure 3A. The second and third power connection rails H+, H- and H- overlap.their respective main parts HT2, HT3 to each other via the second connection surface F2. The second and third power connection rails H+, H- are electrically insulated or separated from each other, for example, by means of an electrical insulation layer arranged between these two power connection rails H+, H-.

[0064] Figure 4 shows a schematic cross-sectional view of a side view of a partial section of the previously described power module LM, in which the side sections of the previously mentioned power connection rails P, H+, H- are clearly shown.

[0065] The connection lugs Z1, Z2, Z3 of the respective power connection rails P, H+, H- are essentially S-shaped and extend from the respective main parts HT1, HT2, HT3 in the direction of the respective corresponding connection surfaces F1, F2, F3 and are physically and electrically connected to the respective corresponding connection surfaces F1, F2, F3, for example by bonding, welding, soldering, sintering or in a similar manner. The connection lugs Z2, Z3 of the second and the respective third power connection rails H+, H- each run at least partially over one of the aforementioned regions B on the top side of the circuit carrier ST.The terminal lugs Z2 of the second power connection rail H+ are additionally bent at their respective sections AS facing the second connection surface F2, so that these sections AS hang above the second connection surface F2 at a distance from the second connection surface F2 and each form a small, low-inductance "loop" (low-inductance intermediate circuit). The "loops" form a space RM on the respective area B of the top side of the circuit carrier ST between the sections AS of the respective terminal lugs Z2 on the one hand and the second connection surface F2 on the other.

[0066] In each of the respective spaces RM, one of the previously mentioned snubber circuits is arranged in a space-saving manner. In the embodiment shown in Figure 4, the snubber circuit has a bond connection V1, an RC element RC (as a standard component) with a capacitor and a resistor. The snubber circuit or its RC element RC is electrically contacted with the corresponding third connection surface F3 via the bond connection V1. The RC element RC is placed on the second connection surface F2 and is electrically contacted with the second connection surface F2. High switching speeds can be achieved thanks to the low-inductance "loops" and the effectively placed snubber circuits.The high-frequency oscillations in currents with voltage peaks that occur during operation of the power module LM with the fast-switching SiC transistor switches T1, T2 are directly damped by the respective snubber circuits (in the respective areas B) that are connected in close proximity with low inductance.

[0067] Subsequent damage caused by these vibrations to the LM power module itself or to other circuit components of the inverter is thus efficiently prevented.

Claims

Patent claims 1. Power module (PM), comprising: - a circuit carrier (ST) with a top surface on which a first electrical connection surface (F1 ) for surface mounting of first transistor switches (T1 ) and a second electrical connection surface (F2) for surface mounting of second transistor switches (T2), as well as third electrical connection surfaces (F3) are formed, wherein the first (F1 ) and the second (F2) connection surfaces are electrically insulated from each other and each extend along a direction of extension (ER) of the circuit carrier (ST), and the third connection surfaces (F3) are electrically insulated from each other and from the first (F1 ) and the second (F2) connection surfaces and are arranged side by side and between the first (F1 ) and the second (F2) connection surfaces in the direction of extension (ER); - Snubber circuits, each of which is formed at least partially on one of several areas (B) of the circuit carrier (ST), wherein the areas (B) each partially span one of the third connection surfaces (F3) and the second connection surface (F2); - wherein the snubber circuits are each electrically connected to the respective corresponding third terminal (F3) and second terminal (F2).

2. Power module (PM) according to claim 1, wherein: - the snubber circuits each have a capacitor (C) and / or a resistor (R), wherein the capacitor (C) and / or the resistor (R) of the respective snubber circuits are each arranged in the respective corresponding area (B).

3. Power module (PM) according to claim 1 or 2, wherein: - each snubber circuit has at least one first bond connection (V1 ), wherein the first bond connection (V1 ) of the respective snubber circuits at least partially spans the respective corresponding area (B).

4. Power module (PM) according to any of the preceding claims, wherein: - the snubber circuits each have at least one conductor connection (L), wherein the conductor connections (L) are formed on the top side of the circuit carrier (ST). Power module (LM) according to one of the preceding claims, wherein: - the first connection surface (F1) and / or the second connection surface (F2) and / or the third connection surfaces (F3) are configured as conductor tracks. Power module (LM) according to one of the preceding claims, wherein: - the first connection surface (F1) has first connection sections (AB) extending transversely to the direction of extension (ER) and in the direction of the second connection surface (F2), wherein the first connection sections (AB) and the third connection surfaces (F3) alternate in the direction of extension (ER); and / or - the second connection surface (F2) has second connection sections extending transversely to the extension direction (ER) in the direction of the first connection surface (F1), wherein the second connection sections and the third connection surfaces (F3) alternate in the extension direction (ER). Power module (LM) according to one of the preceding claims, further comprising: - first transistor switches (T1) surface-mounted on the first terminal pad (F1) and each electrically connected via a second bond connection (V2) to one of the third terminal pads (F3); and / or - Second transistor switches (T2) surface-mounted on the second terminal (F2) and each electrically connected to the first terminal (F1) via a third bond connection (V3). Power module (LM) according to claim 7, wherein: - the transistor switches (T1, T2) are silicon carbide transistor switches. Power module (LM) according to one of the preceding claims, further comprising: - a first power connection rail (P) with first connection lugs (Z1) via which the first power connection rail (P) rests on the first connection surface (F1) and is electrically connected to the first connection surface (F1); and / or - a second power connection rail (H+) with second connection lugs (Z2), via which the second power connection rail (H+) rests on the second connection surface (F2) and is electrically connected to the second connection surface (F2); and / or - a third power connection rail (H-) with third connection lugs (Z3), over which the third power connection rail (H-) rests on the respective third connection surfaces (F3) and is electrically connected to the respective third connection surfaces (F3).

10. Power module (PM) according to claim 9, wherein: - in the event that the power module (LM) has the second (H+) and the third (H-) power connection rail, the second (H+) and the third (H-) power connection rail are arranged largely overlapping each other.

11. Power module (PM) according to claim 10, wherein: - the second (Z2) and / or the third (Z3) connecting flags each run at least partially over one of the areas (B).

12. Power module (LM) according to claim 11, wherein: - the second (Z2) and / or the third (Z3) connection tabs are each shaped in such a way that between the respective second (Z2) and / or the respective third (Z3) connection tabs on the one hand and the respective corresponding areas (B) on the other hand there is a space (RM) in which one of the snubber circuits is at least partially arranged.

13. Power module (LM) according to one of the preceding claims, wherein the first connection surface (F1 ) and the second connection surface (F2) each extend along the extension direction (ER) from a first end region (E1 ) of the circuit carrier (ST) to a second end region (E2) of the circuit carrier (ST) facing away from the first end region (E1 ) in the extension direction (ER).

14. Power module (LM) according to claim 13, wherein the first connection surface (F1) and the second connection surface (F2) extend parallel to each other.

15. Power module (PM) according to any of the preceding claims, wherein: - the circuit carrier (ST) has two outer strip sections (A1 , A2) facing away from each other and a middle strip section (A3) between the two outer strip sections (A1 , A2), wherein the strip sections (A1 , A2 , A3) extend along the extension direction (ER) from the first end region (E1 ) of the circuit carrier (ST) to the second end region (E2) of the circuit carrier (ST); - wherein the first and second connection surfaces (F1 , F2) are each distributed on each of the two outer strip sections A1 , A2, and the third connection surfaces (F3) are formed on the middle strip section (A3).

16. Power module (LM) according to claims 6 and 15, wherein the first (AB) or the second connection sections are formed on the middle strip section (A3).

17. Power module (LM) according to one of the preceding claims, wherein the first connection surface (F1 ) and the second connection surface (F2) and the third connection surfaces (F3) as well as the areas (B) of the circuit carrier (ST) are located on the same surface of the circuit carrier (ST).

18. Inverter, comprising: - a power module (PM) according to any of the preceding claims; - a driver circuit for operating the power module (LM); - a housing wherein the power module (LM) and the driver circuitry are arranged in the housing.

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