POWER MODULE WITH DEFINED CHARGE-REVERSAL PATH AND PRODUCTION METHOD

Abstract

The invention relates to a method for producing a power module (1) and a power module (1), in particular for a medium or high voltage converter (2), comprising at least one power semiconductor module (3), at least one energy storage module (5), at least one cooling device (7), at least two busbars (10), wherein the cooling device (7) is configured to be electrically conductive and is connected to a protective housing (19) shielding at least the power semiconductor module (3) from the environment, which protective housing (19) has at least one insertion opening (20) for inserting and fastening a connecting element (15), and an electrically conductive connecting element (15) is arranged at a predefinable connection position (16) between at least the cooling device (7) and one of the busbars (10) for forming a defined charge-reversal path (17).

Claims

1. A power module for a medium or high voltage converter, comprising: at least one power semiconductor module, at least one energy storage module, at least one cooling device, which is configured to be electrically conductive, and at least two busbars, wherein: the cooling device is configured to be electrically conductive and is connected to a protective housing shielding at least the power semiconductor module from the environment, wherein the protective housing has at least one insertion opening for inserting and fastening an electrically conductive connecting element when the protective housing is closed, and the electrically conductive connecting element is arranged at a predefinable connection position between at least the cooling device and one of the busbars for forming a defined charge-reversal path.

2. The power module according to claim 1, wherein the connecting element is formed to be releasable.

3. The power module according to claim 1, wherein the connecting element has a cross-section which is formed to be more than 10% larger than a minimum cross-section required for forming the defined charge-reversal path and for diverting parasitic discharge currents.

4. The power module according to claim 1, wherein at least two power semiconductor modules are arranged on at least two sides of the busbar with an orientation normal to a plane of the busbar.

5. The power module according to claim 1, wherein the connecting element is arranged so as to electrically connect at least one of the busbars to the cooling device and to go through at least one other busbar and to electrically insulate from it.

6. The power module according to claim 5, wherein the connecting element is arranged at the center of the plane of the busbar.

7. The power module according to claim 1, wherein at least one of the busbars has a laterally protruding connection lug for contacting the connecting element.

8. The power module according to claim 1, wherein an insertion element is formed so as to extend at least partially from the insertion opening of the protective housing in the direction of the nearest busbar.

9. The power module according to claim 1, wherein the insertion opening is closed by means of a closing element.

10. The power module according to claim 1, wherein the protective housing is configured to be electrically conductive and electrically connected to the cooling device.

11. The power module according to claim 10, wherein the connecting element is arranged such that protective housing is electrically connected to the cooling device and one of the busbars.

12. The power module according to claim 1, wherein the cooling device is configured as a load-bearing cooling plate that can be flown through by coolant.

13. The power module according to claim 12, wherein the energy storage module is arranged on a side of the cooling plate opposite the at least one power semiconductor module and the at least two busbars, wherein the cooling plate has a passage for connecting the energy storage module to the at least one power semiconductor module.

14. A method for producing a power module for a medium or high voltage converter, comprising the steps of: providing a power module according to claim 1, fastening a protective housing so as to close off at least the power semiconductor module to the environment, which protective housing has at least one insertion opening for inserting and fastening a connecting element, forming a defined charge-reversal path by affixing the connecting element on the predefinable connection position between at least the cooling device and one of the busbars through the insertion opening when the protective housing is closed.

15. The method according to claim 14, wherein, during or after mounting the connecting element, the insertion opening is closed by means of a closing element.

16. The method according to claim 15, wherein, by mounting the connecting element, the insertion opening is closed, and the connection position between at least the cooling device and one of the busbars and the protective housing is formed.

17. The method according to claim 14, wherein, before fastening the protective housing, a first electrical examination of the power module is performed by applying a first examination voltage to at least one predefinable insulation route.

18. The method according to claim 17, wherein, after the first examination and/or after the fastening of the protective housing, a second electrical examination of the power module is performed by applying a second examination voltage that is increased relative to the first examination voltage to at least one predefinable insulation route.

19. The method according to claim 14, wherein between one of the busbars and the cooling device and/or the protective housing, a control examination regarding the proper functioning and/or the presence of the connecting element is performed.

Description

[0053] These show in a respectively very simplified schematic representation:

[0054] FIG. 1 a schematic representation of a power module with electrical components and a connecting element;

[0055] FIG. 2 a schematic oblique view of a possible arrangement of electrical components on the cooling device with different possible connection positions of the connecting element;

[0056] FIG. 3 different possible embodiments of the power module with connection positions, going through the busbars (a) and/or arranged centrally (b) or on a connection lug (c);

[0057] FIG. 4 a schematic oblique view of a possible embodiment of a power module with energy and power semiconductor modules arranged on both sides of the cooling device.

[0058] First of all, it is to be noted that in the different embodiments described, equal parts are provided with equal reference numbers and/or equal component designations, where the disclosures contained in the entire description may be analogously transferred to equal parts with equal reference numbers and/or equal component designations. Moreover, the specifications of location, such as at the top, at the bottom, at the side, chosen in the description refer to the directly described and depicted figure and in case of a change of position, these specifications of location are to be analogously transferred to the new position.

[0059] FIG. 1 shows a schematic representation of a power module 1 according to the invention for a medium or high voltage converter 2 that is not specially represented. The power module 1 comprises at least one power semiconductor module 3 as well as at least one energy storage module 5 as well as at least one cooling device 7. The power semiconductor module 3 can be connected to the energy storage module 5 for example via busbars 10 and/or a connection terminal 14. Such arrangements are known in detail to the person skilled in the art and are only depicted schematically here. The current supply and/or contacting with external power connections is and/or schematically with the aid of a conductor bar 13. The busbars 10 that usually have a flat configuration are separated from one another by an insulation layer 12. The potential of the conductor bars 13 alternating at a high frequency can lead to an unwanted storing of electrical charge between the conductor bars 13 and other, particularly flat, components of the power module 1. This is referred to, among other designations, as parasitic capacity 18 and is adumbrated by the corresponding symbols and dashed connection lines between possible electrical components of the power module 1, on which such parasitic capacities 18 can occur.

[0060] The schematic representation in FIG. 1 makes it possible to comprehend the functional principle of the power module 1 configured according to the invention, in which a cooling device 7 is configured to be electrically conductive and on which the at least one power semiconductor module 3 is arranged preferably in a directly heat transferring manner. The power semiconductor module 3 comprises at least one power semiconductor module 4 such as an IGBT or similar suitable electronic parts. A protective housing 19 is connected to the cooling device 7 for protection against the environment. According to the invention, a defined charge-reversal path 17 and/or current path is formed between at least the cooling device 7 and one of the busbars 10 by means of a connecting element 15, for improving the electromagnetic compatibility. The charge-reversal path 17, shown in dashed lines, is formed at a suitable connection position 16 by means of a connecting element 15. According to the invention, the mounting of the connecting element 15 takes place as the last electrically effective element of the power module 1. This is made possible by an insertion opening 20 in the protective housing 19. This way, a defined current and/or charge-reversal path 17 can be created for unavoidable parasitic discharge currents, and the influence of parasitic capacities 18 at undesired locations can be mostly reduced or even avoided, whereby the EMC as well as defects and/or material degradation of individual components can be reduced.

[0061] The principle of forming a defined charge-reversal path 17 by mounting the connecting element 15 at a predefinable connection position 16 as seen in FIG. 1, can be applied to FIGS. 2 to 4 and is further explained in the following with the aid of some possible exemplary embodiments.

[0062] The connecting element 15, which is shown as a screw by way of example in FIG. 1, can, as in FIG. 2 in combination with FIG. 3, be arranged so as to electrically connect one of the busbars 10 to the cooling device 7, wherein at least one of the busbars 10 is contacted. In FIG. 2, two power semiconductor modules 3 are arranged, by way of example, on opposing sides of the busbars 10. Such an arrangement makes short electrical conduction paths possible and thereby improves the electromagnetic compatibility by decreasing parasitic inductances. In FIG. 2, it can further be seen that the connection position 16 between the cooling device 7 and/or the cooling plate 8 to at least one of the busbars is possible at different positions. The connection position 16 can, for example, be configured on a connection lug 11 protruding laterally on one of the busbars 10 for contacting the connecting element 15 to the cooling plate 8.

[0063] With reference to the preceding discussion of FIGS. 1 and 2, further exemplary embodiments of power modules 1 according to the invention are shown in FIGS. 3a to 3d. The busbars 10 can be shielded from one another and/or supported by an insulation layer 12 and/or toward the cooling device by insulators 9.

[0064] FIG. 3a represents a schematic cross-sectional view, in which the lower busbar 10 in the vertical direction is connected to the conductive cooling device and/or cooling plate 8 by the connecting element 15. In the representation of FIG. 3a, it can further be seen that an insertion element 22 is formed on the insertion opening 20 of the protective housing 19 in the direction of the cooling device. This insertion element 22 preferably formed as a pipe or a channel makes the loss-secure insertion and mounting of the connecting element 15 possible.

[0065] In FIG. 3b, a preferred possible embodiment of a connection position 16 is adumbrated, wherein the connection position is arranged at the center 23 in a plane of the busbars 10. In this case, the uppermost busbar 10 in the vertical direction is connected to the cooling device 7 and/or cooling plate 8 via the connecting element 15.

[0066] A further possible arrangement of the connecting element 15 can be seen from the sectional view in FIG. 3c, wherein the connection position 16 is formed between a busbar 10 and the cooling device 7 by means of a connection lug 11 protruding laterally on the busbar.

[0067] In FIG. 3d, a further and possibly independent embodiment of the power module 1 according to the invention is shown. In the exemplary depiction of 3d, the protective housing is configured to be electrically conductive and is electrically connected to the cooling device 7 and one of the busbars. The predefinable connection position 16 comprises, in this case, three points along the connecting element 15, on which electrical contacts are formed. In the situation shown, mounting the connecting element 15 simultaneously closes the insertion opening 20 of the protective housing 19. A situation, in which the electrical connecting element 15 is configured as a partially insulating screw, wherein an insulation with respect to the protective housing is formed in the region of the shaft and/or head, is not depicted. In both cases, however, the connecting element 15 and a closing element 21 provided for closing the insertion opening 20 are configured to be a single part.

[0068] The connecting elements 15 can have an electrically conductive cross-section which simultaneously contributes to a targeted heat dissipation to the cooling device. In particular, it can be advantageous if the effective cross-section is formed to be at least 10% larger than the required minimum cross-section for the electrical connection and formation of the defined charge-reversal path 17. Moreover, in the case of, e.g. screw-type connecting elements 15, as it can be seen in FIGS. 3a-3c, for example, a broadened screw head can be used for an improved support and/or contacting of the busbar 10, whereby an increased heat absorption and/or heat dissipation can be favored.

[0069] FIG. 4 shows a schematic oblique view of a power module 1. The selected view shows that the at least one power semiconductor module 3 as well as the at least one energy storage module 5 are arranged on opposing sides of the cooling plate 8. A connection of the energy storage module 5 to the power semiconductor module 3 and/or an auxiliary module 24 is possible due to the formation of passage 25 going through the cooling plate 8. In the region of said passage 25, preferably a connection terminal 14 for connecting the electrical components can be located. Such a situation is particularly advantageous in combination with an arrangement of the components of the power module 1 that is symmetrical in the transverse direction and/or longitudinal direction, as it is schematically adumbrated in FIG. 2. Through one or multiple passages 25, the electrical connection paths can be selected with a relatively short length.

[0070] Furthermore, FIG. 4 shows that for closing the insertion opening 20 of the protective housing 19, a separate closing element 21 can be provided. Such a closing element 21 is provided as an electrically non-effective element and serves for closing the protective housing 19 to the environment.

[0071] The person skilled in the art can easily gather from the drawings of FIGS. 1 to 4 that according to the invention, possible electrical examinations can be performed easily on various, predefinable insulation routes, before and/or after the protective housing 19 has been fastened.

[0072] Moreover, FIG. 4 shows that a symmetrical arrangement of the electrical components makes the formation of current paths of approximately the same length possible. This favors the reduction of the influence of parasitic capacities and/or inductances and improves the EMC. This is a special advantage in the case of flat busbars 10 and/or conductor bars 13, which would be prone to forming parasitic capacities 18 with respect to a protective housing 19 and/or the electrically conductive cooling plate 8.

[0073] The exemplary embodiments show possible embodiment variants, and it should be noted in this respect that the invention is not restricted to these particular illustrated embodiment variants of it, but that rather also various combinations of the individual embodiment variants are possible and that this possibility of variation owing to the teaching for technical action provided by the present invention lies within the ability of the person skilled in the art in this technical field.

[0074] The scope of protection is determined by the claims. However, the description and the drawings are to be adduced for construing the claims. Individual features or feature combinations from the different exemplary embodiments shown and described may represent independent inventive solutions. The object underlying the independent inventive solutions may be gathered from the description.

[0075] All indications regarding ranges of values in the present description are to be understood such that these also comprise random and all partial ranges from it, for example, the indication 1 to 10 is to be understood such that it comprises all partial ranges based on the lower limit 1 and the upper limit 10, i.e. all partial ranges start with a lower limit of 1 or larger and end with an upper limit of 10 or less, for example 1 through 1.7, or 3.2 through 8.1, or 5.5 through 10.

[0076] Finally, as a matter of form, it should be noted that for ease of understanding of the structure, elements are partially not depicted to scale and/or are enlarged and/or are reduced in size.

LIST OF REFERENCE NUMBERS

[0077] 1 power module [0078] 2 medium or high voltage converter [0079] 3 power semiconductor module [0080] 4 power semiconductor [0081] 5 energy storage module [0082] 6 energy storage [0083] 7 cooling device [0084] 8 cooling plate [0085] 9 insulator [0086] 10 busbar [0087] 11 connection lug [0088] 12 insulation layer [0089] 13 conductor bar [0090] 14 connection terminal [0091] 15 connecting element [0092] 16 connection position [0093] 17 charge-reversal path [0094] 18 parasitic capacity [0095] 19 protective housing [0096] 20 insertion opening [0097] 21 closing element [0098] 22 insertion element [0099] 23 center of the busbar plane [0100] 24 auxiliary module [0101] 25 passage