Power module for the drive system of an electrically powered vehicle

Abstract

The invention relates to a power module (100) for a drive of an electrically operated vehicle for electrical connection with at least one intermediate circuit capacitor (40), comprising at least a plurality of submodules (10, 20, 30), each of which has a positive terminal (12, 22, 32) and a negative terminal (16, 26, 36) for a high-voltage supply voltage, wherein in intended operation the positive terminals (12, 22, 32) of the plurality of submodules (10, 20, 30) are electrically connected to an electrical terminal of the at least one intermediate circuit capacitor (40) and the negative terminals (16, 26, 36) of the plurality of submodules (10, 20, 30) are electrically connected to a second electrical terminal of the at least one intermediate circuit capacitor (40).The power module (100) comprises a first connecting piece (60) which electrically connects the positive terminals (12, 22, 32) of the majority of submodules (10, 20, 30) and a second connecting piece (62) which electrically connects the negative terminals (16, 26, 36) of the majority of submodules (10, 20, 30).

Description

[0001] The invention relates to a power module for a drive of an electrically operated vehicle for electrical connection to at least one intermediate circuit capacitor.

[0002] Drive converters for electrically powered vehicles typically have several half-bridges in the form of semiconductor modules, each with a positive and a negative connection for the high-voltage supply voltage. These connections are typically implemented as connecting elements made of sheet metal strips, to which an intermediate circuit capacitor with its connecting elements, also in the form of sheet metal strips, is additionally connected to support the supply voltage. The sheet-metal connecting elements cause unwanted parasitic inductances, also known as stray inductances, between the capacitor and the half-bridge. The inductance leads to an induced voltage when the current changes due to the switching process in the semiconductor switching elements.Because of this induced voltage, the switching speed of the semiconductor switching elements must be reduced so that the maximum permissible voltage on the semiconductor switching elements is not exceeded. This results in higher switching losses and reduces the efficiency of the drive.

[0003] For example, DE 10 2020 207 689 A1 describes a power module that has an input contact with a positive pole and a negative pole for feeding in an input current. The power module further comprises a snubber capacitor connected between the positive pole and the negative pole. The power module further comprises a plurality of power switches connected in parallel with the snubber capacitor. These semiconductor-based power switches serve to generate an output current based on the input current by controlling the individual power switches.

[0004] DE 10 2020 207 701 A1 also describes a power module with a plurality of circuit breakers connected in parallel to a snubber capacitor. The plurality of circuit breakers is divided into several groups. For voltage smoothing, the power module further comprises an intermediate circuit capacitor arrangement connected in parallel to the circuit breakers. The intermediate circuit capacitor arrangement comprises several intermediate circuit capacitors, which are designed, for example, as plate capacitors. Each of the intermediate circuit capacitors is assigned to one of the plurality of circuit breaker groups. Thus, all intermediate circuit capacitors are assigned to all circuit breaker groups in a one-to-one relationship.

[0005] An object of the invention is to provide an improved power module for a drive of an electrically operable vehicle for electrical connection to at least one intermediate circuit capacitor.

[0006] The above-mentioned problem is solved by the features of the independent claim.

[0007] Advantageous embodiments and advantages of the invention emerge from the further claims, the description and the drawing.

[0008] According to one aspect of the invention, a power module for a drive of an electrically operated vehicle for electrical connection to at least one intermediate circuit capacitor is proposed, at least comprising a plurality of sub-modules, each having a positive terminal and a negative terminal for a high-voltage supply voltage, wherein in normal operation the positive terminals of the plurality of sub-modules are electrically connected to an electrical terminal of the at least one intermediate circuit capacitor and the negative terminals of the plurality of sub-modules are electrically connected to a second electrical terminal of the at least one intermediate circuit capacitor.The power module further comprises a first connector that electrically connects the positive terminals of the plurality of sub-modules and a second connector that electrically connects the negative terminals of the plurality of sub-modules.

[0009] In the proposed power module, an additional cross connection in the form of two connecting pieces of the intermediate circuit capacitor is inserted between the sub-modules, which are designed, for example, as half-bridge modules.

[0010] This cross-connection serves to reduce parasitic inductance in the terminals of sub-modules and the DC link capacitor. Reducing parasitic inductance enables faster switching of the power module. It can also improve electromagnetic compatibility (EMC).

[0011] Furthermore, the cross-connection connectors also allow direct current flow between the sub-modules, reducing the current load on the DC link capacitor's connecting elements. This is advantageously achieved by dividing the connections into the standard DC link capacitor connections and the additional cross-connections.

[0012] The proposed power module therefore advantageously exhibits lower switching losses, thereby increasing the efficiency of the drive.

[0013] The additional connecting pieces also increase the current carrying capacity of the electrical connection between the sub-modules of the power module, which are designed as half-bridges, for example.

[0014] According to an advantageous embodiment of the power module, the positive terminals and the negative terminals of the plurality of sub-modules can each be designed as strip-shaped connecting elements, in particular in the form of sheet metal strips. Alternatively or additionally, the electrical terminals of the at least one intermediate circuit capacitor can be designed as strip-shaped connecting elements, in particular in the form of sheet metal strips. Alternatively or additionally, the first connecting piece and the second connecting piece can each be designed as flat strips, in particular in the form of sheet metal strips, or cuboid-shaped or as an angle piece. In particular, the first connecting piece and the second connecting piece can each have a thickness of at least 1 mm and a width of at least 10 mm.Parasitic inductances can be caused, in particular, by the connecting elements of the sub-modules and the intermediate circuit capacitor, which are designed as sheet metal strips. These parasitic inductances can be advantageously reduced by the connecting pieces of the cross connection between the terminals of the sub-modules, which are also designed as sheet metal strips.

[0015] According to an advantageous embodiment of the power module, the first connecting piece and the second connecting piece can each have a straight extension. This allows the connecting pieces to electrically connect the positive terminals of the sub-modules and the negative terminals with particularly low inductance.

[0016] According to an advantageous embodiment of the power module, the first connecting piece and the second connecting piece can be arranged spatially one above the other, at least in sections. This allows for a compact and, at the same time, low-inductance connection between the positive and negative terminals. The stacked arrangement of the connecting pieces advantageously further reduces induced voltages due to the at least partial mutual cancellation of induced magnetic fields.

[0017] According to an advantageous embodiment of the power module, the first connecting piece and the second connecting piece can extend parallel to each other in one plane or parallel to each other in parallel planes. Thus, the connecting pieces can electrically connect the positive terminals of the sub-modules and the negative terminals with particularly low inductance.

[0018] According to an advantageous embodiment of the power module, an air gap can be formed between the first connecting piece and the second connecting piece. Alternatively or additionally, an insulating body can be arranged between the first connecting piece and the second connecting piece. The air gap and the insulating body, which can be designed, for example, as an insulating foil, can ensure the necessary insulation distance between the two connecting pieces. By means of an insulating body, the distance between the two connecting pieces can advantageously be reduced compared to the air gap. The risk of a short circuit between the two connecting pieces due to contamination or foreign matter is also reduced.

[0019] According to an advantageous embodiment of the power module, the first connecting piece and the second connecting piece can be arranged transversely, in particular perpendicularly, to the connecting elements of the plurality of sub-modules and / or to the connecting elements of the at least one intermediate circuit capacitor. Such an arrangement of the connecting pieces allows parasitic inductances of the electrical connection between the sub-modules and the intermediate circuit capacitor to be further reduced.

[0020] According to an advantageous embodiment of the power module, the first connecting piece and the second connecting piece can have connection points for coupling the high-voltage supply voltage to the positive and negative terminals of the respective sub-modules. This allows for a reliable and low-inductance coupling of the connecting pieces to the connecting elements of the sub-modules.

[0021] According to an advantageous embodiment, the power module can be designed as a drive converter for operating an electric vehicle drive, wherein the submodules can be designed as half-bridges. The drive converter can have at least three half-bridges with respective connections for providing three electrical phase currents for controlling a drive motor. Conventional drive motors of electric vehicles can be advantageously operated in this way.

[0022] According to an advantageous embodiment of the power module, the positive and negative terminals of the three half-bridges can each be electrically connected in parallel with at least one intermediate circuit capacitor during normal operation. Each half-bridge can thus advantageously have its own intermediate circuit capacitor. This enables particularly effective operation of the power module for controlling the electric drive of a vehicle.

[0023] Further advantages will become apparent from the following description of the drawings. The drawings illustrate an exemplary embodiment of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0024] Showing: Fig. 1 a plan view of a power module for driving an electrically operable vehicle according to an embodiment of the invention, which is electrically connected to an intermediate circuit capacitor; and Fig. 2 a side view of the power module according to Fig. 1.

[0025] In the figures, identical or similar components are numbered with the same reference numerals. The figures show only examples and are not to be understood as limiting.

[0026] Fig. 1 shows a plan view of a power module 100 for driving an electrically operable vehicle according to an embodiment of the invention, which is electrically connected to an intermediate circuit capacitor 40, while in Fig. 2 shows a side view of the power module 100.

[0027] The power module 100 comprises three sub-modules 10, 20, 30, each having a positive terminal 12, 22, 32 and a negative terminal 16, 26, 36 for a high-voltage supply voltage.

[0028] The power module 100 represents, for example, a drive converter 200 for operating an electric vehicle drive, in which the three sub-modules 10, 20, 30 are designed as half-bridges 90, 92, 94.

[0029] The half-bridges 90, 92, and 94 provide three electrical phase currents, typically designated U, V, and W, at respective terminals 91, 93, and 95 for controlling a drive motor. The half-bridges 90, 92, and 94 each have semiconductor modules 54, 56, and 58 with the respective switching elements, such as switching transistors.

[0030] During normal operation, the sub-modules 10, 20, 30 are electrically connected to an electrical connection of an intermediate circuit capacitor 40 via their positive connections 12, 22, 32 and to a second electrical connection of the intermediate circuit capacitor 40 via their negative connections 16, 26, 36.

[0031] The positive terminals 12, 22, 32 and the negative terminals 16, 26, 36 of the sub-modules 10, 20, 30 can, for example, as shown, each be designed as strip-shaped connecting elements 14, 18, 24, 28, 34, 38, in particular in the form of sheet metal strips.

[0032] The electrical connections of the intermediate circuit capacitor 40 can also be designed, as shown, as strip-shaped connecting elements 42, 44, 46, 48, 50, 52, particularly in the form of sheet metal strips. The strip-shaped connecting elements 42, 44, 46, 48, 50, 52 of the intermediate circuit capacitor 40 are each electrically connected, for example, welded, to the connecting elements 14, 18, 24, 28, 34, 38 of the submodules 10, 20, 30.

[0033] In the illustrated embodiment, the intermediate circuit capacitor 40 is shown as a block with the separately led-out connecting elements 42, 44, 46, 48, 50, 52, each separately for each sub-module 10, 20, 30. The intermediate circuit capacitor can be configured inside the block as a single capacitor, each with branched connections. Alternatively, however, it is also possible for three separate capacitors to be arranged inside the block, which are led out to the respective connecting elements 42, 44, 46, 48, 50, 52, so that the three half-bridges 90, 92, 94 are each electrically connected in parallel to at least one intermediate circuit capacitor 40 during normal operation.

[0034] The positive terminals 12, 22, 32 of the sub-modules 10, 20, 30 are electrically connected to a first connecting piece 60 and the negative terminals 16, 26, 36 of the sub-modules 10, 20, 30 are electrically connected to a second connecting piece 62.

[0035] The first connecting piece 60 and the second connecting piece 62 can advantageously each be designed as flat strips, in particular in the form of sheet metal strips, or cuboid-shaped or as an angle piece.

[0036] As particularly in Fig. 2 in the side view, in the illustrated embodiment the two connecting pieces 60, 62 are designed as angle pieces, are arranged at least in sections spatially one above the other and extend parallel to each other in parallel planes.

[0037] An insulating body 68, for example in the form of an insulating foil, is arranged between the first connecting piece 60 and the second connecting piece 62. Alternatively, an air gap can also be arranged between the two connecting pieces 60, 62 for insulation.

[0038] The two connecting pieces 60, 62 extend in a straight line, as shown in the plan view in Fig. 1 is recognizable.

[0039] In an alternative embodiment, the connecting pieces 60, 62 could also extend parallel to each other in a plane.

[0040] For the electrical dimensioning of conventional electric drives, the two connecting pieces 60, 62 can, for example, each have a thickness 64 of at least 1 mm and a width 66 of at least 10 mm. A thickness 64 is, for example, in the first connecting piece 60 in Fig. 2. A width 66 is exemplary for the second connecting piece 62 in Fig. 1 marked.

[0041] The two connecting pieces 60, 62 have connection points 70, 72, 74, 76, 78, 80 for coupling the high-voltage supply voltage to the positive terminal 12, 22, 32 and the negative terminal 14, 24, 34 of the respective sub-module 10, 20, 30. The connection points 70, 72, 74, 76, 78, 80 can be designed, for example, as soldering points or welding points.

[0042] For a particularly low-inductance design, the two connecting pieces 60, 62 can be arranged transversely, in particular perpendicularly, to the connecting elements 14, 18, 24, 28, 34, 38 of the sub-modules 10, 20, 30 and / or to the connecting elements 42, 44, 46, 48, 50, 52 of the at least one intermediate circuit capacitor 40, as in the illustrated embodiment. List of reference symbols 10 Submodule 12 positive connection 14 Connecting element 16 negative terminal 18 Connecting element 20 submodules 22 positive connection 24 connecting element 26 negative terminal 28 Connecting element 30 submodules 32 positive connection 34 connecting element 36 negative terminal 38 connecting element 40 DC link capacitor 42 connecting element 44 Connecting element 46 connecting element 48 connecting element 50 connecting element 52 connecting element 54 semiconductor module 56 semiconductor module 58 semiconductor module 60 first connecting piece 62 second connecting piece 64 thickness 66 width 68 insulation bodies 70 connection point 72 connection point 74 connection point 76 connection point 78 connection point 80 connection point 90 Half Bridge 91 connection 92 Half Bridge 93 connection 94 Half Bridge 95 connection 100 power modules 200 drive inverters QUOTES CONTAINED IN THE DESCRIPTION

[0000] 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

[0000] DE 10 2020 207 689 A1

[0003] DE 10 2020 207 701 A1

[0004]

Claims

[1] Power module (100) for a drive of an electrically operable vehicle for electrical connection to at least one intermediate circuit capacitor (40), at least comprising a plurality of sub-modules (10, 20, 30), each having a positive terminal (12, 22, 32) and a negative terminal (16, 26, 36) for a high-voltage supply voltage, wherein, during normal operation, the positive terminals (12, 22, 32) of the plurality of sub-modules (10, 20, 30) are electrically connected to an electrical terminal of the at least one intermediate circuit capacitor (40) and the negative terminals (16, 26, 36) of the plurality of sub-modules (10, 20, 30) are electrically connected to a second electrical terminal of the at least one intermediate circuit capacitor (40), and a first connector (60) electrically connecting the positive terminals (12, 22, 32) of the plurality of sub-modules (10, 20, 30) and a second connector (62) electrically connecting the negative terminals (16, 26, 36) of the plurality of sub-modules (10, 20, 30). [2] Power module according to claim 1, wherein the positive terminals (12, 22, 32) and the negative terminals (16, 26, 36) of the plurality of sub-modules (10, 20, 30) are each designed as strip-shaped connecting elements (14, 18, 24, 28, 34, 38), in particular in the form of sheet metal strips, and / or wherein the electrical connections of the at least one intermediate circuit capacitor (40) are designed as strip-shaped connecting elements (42, 44, 46, 48, 50, 52), in particular in the form of sheet metal strips, and / or wherein the first connecting piece (60) and the second connecting piece (62) are each designed as flat strips, in particular in the form of sheet metal strips, or cuboid-shaped or as an angle piece, in particular wherein the first connecting piece (60) and the second connecting piece (62) each have a thickness (64) of at least 1 mm and a width (66) of at least 10 mm. [3] Power module according to claim 1 or 2, wherein the first connecting piece (60) and the second connecting piece (62) each have a rectilinear extension. [4] Power module according to one of the preceding claims, wherein the first connecting piece (60) and the second connecting piece (62) are arranged spatially one above the other at least in sections. [5] Power module according to one of the preceding claims, wherein the first connecting piece (60) and the second connecting piece (62) extend parallel to each other in one plane or parallel to each other in parallel planes. [6] Power module according to one of the preceding claims, wherein an air gap is formed between the first connecting piece (60) and the second connecting piece (62) and / or wherein an insulating body (68) is arranged between the first connecting piece (60) and the second connecting piece (62). [7] Power module according to one of claims 2 to 6, wherein the first connecting piece (60) and the second connecting piece (62) are arranged transversely, in particular perpendicularly, to the connecting elements (14, 18, 24, 28, 34, 38) of the plurality of sub-modules (10, 20, 30) and / or to the connecting elements (42, 44, 46, 48, 50, 52) of the at least one intermediate circuit capacitor (40). [8] Power module according to one of the preceding claims, wherein the first connecting piece (60) and the second connecting piece (62) have connection points (70, 72, 74, 76, 78, 80) for coupling the high-voltage supply voltage to the positive terminal (12, 22, 32) and the negative terminal (14, 24, 34) of the respective sub-module (10, 20, 30). [9] Power module according to one of the preceding claims, designed as a drive converter (200) for operating an electric vehicle drive, wherein the sub-modules (10, 20, 30) are designed as half-bridges (90, 92, 94), wherein the drive converter (200) has at least three half-bridges (90, 92, 94) with respective connections (91, 93, 95) for providing three electrical phase currents for controlling a drive motor. [10] Power module according to claim 9, wherein the positive terminals (12, 22, 32) and the negative terminals (14, 24, 34) of the three half-bridges (90, 92, 94) are each electrically connected in parallel to at least one intermediate circuit capacitor (40) during normal operation.

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