ELECTRICAL INVERTER SYSTEM

Abstract

An electrical inverter system including a first heat sink, a second heat sink and an electrical capacitor, stacked in that order. These three components can be fixed by a fixing means in such a way that they are not displaceable against each other and at least partially lie flat against each other. Furthermore, the system includes a semiconductor power module clamped between the heat sinks, and electrical contact elements electrically connecting the electrical capacitor and the semiconductor power module.

Claims

1. Electric inverter system comprising at least the components first heat sink, second heat sink and electrical capacitor, where the components are stacked in the mentioned order, further comprising at least one fixing means, wherein the three said components are fixed by the fixing means in such a way that they cannot be displaced relative to one another and are at least partially in surface contact with one another, further comprising a semiconductor power module clamped between the heat sinks, and further comprising electrical contact elements electrically connecting the electrical capacitor and the semiconductor power module.

2. The electrical inverter system of claim 1, wherein the fixing means is a screw.

3. The electrical inverter system of claim 2, wherein at least one of the components includes a mating thread for securing the screw.

4. The electrical inverter system according to claim 1, wherein the electrical capacitor comprises an electromagnetic interference filter.

5. The electrical inverter system according to claim 1, wherein surfaces of the semiconductor power module lie flat against the heat sinks so that heat transfer between the semiconductor power module and the heat sinks is improved.

6. The electrical inverter system according to claim 1, wherein the semiconductor power module can be clamped between the heat sinks only in a predetermined orientation.

7. The electrical inverter system of claim 6, wherein at least one of the heat sinks includes a lug that provides the orientation of the semiconductor power module.

8. The electrical inverter system according to claim 1, wherein the semiconductor power module is exposed to the outside at a first side of the system.

9. The electrical inverter system of claim 8, wherein the semiconductor power module includes an AC connector on the first side that provides the orientation of the semiconductor power module.

10. The electrical inverter system of claim 9, wherein the semiconductor power module comprises an output current sensor.

11. The electrical inverter system of claim 1, wherein a gate driver board is attached to the first side of the capacitor.

12. The electrical inverter system of claim 11, wherein at least one controller board is attached to the gate driver board and electrically contacted to the semiconductor power module, or wherein the controller board (10A) is embedded in the gate driver board (10B).

13. The electrical inverter system according to claim 1, wherein the electrical capacitor comprises a high voltage DC connector.

14. The electrical inverter system according to claim 1, wherein the electrical capacitor comprises an input current sensor.

15. The electrical inverter system according to claim 1, wherein one of the heat sinks comprises through holes in which pressure contacts are embedded as electrical contact elements.

16. Method of assembling an electrical inverter system comprising the following steps: provide a first heat sink, a second heat sink, and an electrical capacitor, provide a semiconductor power module and fixing means, arranging the semiconductor power module on a first of the heat sinks, covering the first heat sink and the semiconductor power module by a second of the heat sinks, positioning of the heat sinks on top of each other with the semiconductor power module and the electrical capacitor arranged in between, so that electrical contact surfaces of the capacitor and the semiconductor power module are superimposed and can be contacted by electrical contact elements, attaching at least one fixing means, the fixing means fixing the two heat sinks and the capacitor in such a way that the said components cannot be displaced with respect to one another and at least partially lie flat against one another, and wherein the semiconductor power module is clamped between the heat sinks by fixing said components.

17. The method according to claim 16, wherein the fixing means are screws and wherein at least one of said components has mating threads for fixing the screws.

18. The method of claim 16, further comprising fixing a gate driver board to a first side of the electrical capacitor.

19. The electrical inverter system of claim 1, wherein each of the three components is at least partially in surface contact with the respective adjacent component.

20. The electrical inverter system of claim 3, wherein the first heat sink, the second heat sink, and the electrical capacitor have holes arranged one above the other to form screw connections.

21. Method according to claim 16, wherein each of the three components is at least partially in surface contact with the respective adjacent component.

22. The method of claim 17, wherein said three components have holes for forming a screw connection.

Description

[0133] The figures show:

[0134] FIG. 1: Front perspective view of a first embodiment of an electrical inverter system,

[0135] FIG. 2: Perspective view of the first embodiment of the electric inverter system from the rear side,

[0136] FIG. 3: Perspective view of a first embodiment of semiconductor power modules and associated contact elements from the bottom side,

[0137] FIG. 4: Perspective view of a first embodiment of a heat sink,

[0138] FIG. 5: Exploded view of a second embodiment of an electrical inverter system from a side perspective,

[0139] FIG. 6: Bottom view of a second embodiment of a semiconductor power module.

[0140] Similar or apparently identical elements in the figures are marked with the same reference sign. The figures and the proportions in the figures are not to scale.

[0141] FIG. 1 shows a first embodiment of the electrical inverter system 1 in a perspective oblique view. The electrical inverter system 1 comprises several components arranged one above the other, mechanically fixed to one another and electronically interconnected.

[0142] The components include a first heat sink 2 and a second heat sink 3, and a capacitor 4. The capacitor 4 is sealed to the outside by a capacitor housing 4A.

[0143] In the present embodiment, the first heat sink 2 is the lowest component, which may be fixed to another assembly, and on which the second heat sink 3 and the capacitor 4 are mounted. For example, the entire assembly may be fixed to an engine.

[0144] In the embodiment example, three semiconductor power modules 5 are arranged between the first heat sink 2 and the second heat sink 3. The semiconductor power modules 5 are precisely embedded in recesses provided for this purpose between the heat sinks 2 and 3.

[0145] The recesses have openings 6 on the front side 3A of the heat sinks. The openings 6 ensure the accessibility of the semiconductor power modules 5 for electrical contacting to the outside.

[0146] For this purpose, the semiconductor power modules 5 each comprise a front tab 7. Via the front tabs 7, the outgoing alternating current can be conducted to the intended application. The application is, for example, an engine, in particular an automotive engine.

[0147] For electrical contacting, the tabs 7 are screwed, for example, to external contacts 8A provided for this purpose by means of metal screws 8B. The supporting part 8C serves only as a carrier and supports the mechanical fixation of the external contacts 8A.

[0148] The tabs 7 comprise an electrically conductive material, preferably a metal with high electrical conductivity.

[0149] In addition to the tabs 7, the semiconductor power module 5 further comprises metallic pins 9 for contacting the modules 5 with associated controller boards 10A. Each semiconductor power module 5 has its own controller board 10A. In the present embodiment example, seven pins 9 are provided per semiconductor power module 5. Thus, the semiconductor power modules 5 can be controlled via the controller boards 10A.

[0150] A gate driver board 10B is attached directly to the front of the capacitor housing 4A in the present embodiment. For this purpose, the capacitor housing 4A has four holding pins 4B. The gate driver board 10B is plugged onto these holding pins 4B.

[0151] Alternatively, the gate driver board 10B may be attached to the front of the capacitor housing 4A by screw connections.

[0152] The gate driver board 10B drives the controller boards 10A, which are either directly embedded in the gate driver board 10B or mounted on the outside thereof as in the present embodiment. The controller boards 10A are contacted to the semiconductor power modules 5 via the pins 9 as described above.

[0153] At the rear side of the semiconductor power module 5, the recesses as shown in FIG. 2 are also exposed through openings 6 in the heat sink 2 or 3, so that the semiconductor power module 5 can also be electrically contacted at the rear side 3B.

[0154] In the present embodiment, the semiconductor power modules 5 each have three metal tabs 11 for this purpose. The tabs are bent parallel to the outside of the second heat sink by 90° in the direction of the capacitor 4 in order to make electrical contact with corresponding contact elements of the capacitor 4.

[0155] The corresponding contact elements are, for example, contact surfaces of a busbar 12 of the capacitor 4, which are exposed on the outside of the capacitor housing 4A.

[0156] For contacting, the metal tabs 11 are welded to the busbar 12.

[0157] Screw connections are an alternative form of contacting (not shown). Holes are drilled in the contact surfaces of the busbar 12 and the metal tabs 11. By inserting a metallic, electrically conductive screw, capacitor 4 and semiconductor power module 5 can then be electrically connected.

[0158] The capacitor housing 4A comprises a plastic material. On the side facing the second heat sink 3, the capacitor housing 4A has a mounting section 4C for mounting the heat sinks 2/3 to the capacitor housing 4A.

[0159] In the present embodiment, the base area of the mounting section 4C is widened compared to the rest of the capacitor housing 4A. Thus, the base area of the mounting section 4C of the capacitor 4 has the same dimensions as the heat sink 4.

[0160] In an alternative embodiment, the base area of the entire capacitor housing 4A may have the same dimensions as the heat sinks 2 or 3. In a further embodiment, the mounting section 4C has smaller dimensions than the heat sinks 2/3.

[0161] The mounting section 4C is used to attach the capacitor 4 to the second heat sink 3. For this purpose, eight holes 13, four each at the front and rear of the capacitor 4, are recessed in the mounting section 4C perpendicular to the base of the capacitor. The holes 13 may have a mating thread.

[0162] The drilled holes 13 are placed collinearly above corresponding drilled holes 13 in the second and first heat sink 2. At least the holes 13 in the first heat sink 2 have a mating thread in the present embodiment. Screws 13A can thus be used to easily connect and fix the aforementioned components to each other.

[0163] The hole 13 in the first heat sink 2 can be continuous, so that the same screws 13A can be used to mount the entire system 1 on another component. Such a component may, for example, be a motor.

[0164] In another embodiment, the entire system 1 may be stacked in reverse order. The screws 13A are then inserted into the holes 13 from the side of the first heat sink 2 and fixed in a mating thread in the holes 13 in the mounting section 4C of the capacitor 4.

[0165] In alternative embodiments, fewer or more screw connections can be used to fix the aforementioned components. The screw connections are arranged at regular intervals in order to achieve the most uniform pressure distribution possible on the components (first heat sink 2, second heat sink 3, capacitor 4).

[0166] The capacitor 4 includes within the capacitor housing 4A at least one capacitor element, such as a DC capacitor element, and further includes an electromagnetic interference (EMI) filter.

[0167] The EMI filter is either integrated directly in the capacitor element or alternatively designed as an independent component but installed directly with the capacitor element. In both cases, both components are arranged together in the capacitor housing 4A. This eliminates the need for separate mounting of the EMI filter. The elimination of this additional assembly step simplifies the assembly process and reduces the susceptibility to errors during assembly. Costs and time of the assembly process can be reduced.

[0168] For the required ground contacting of the EMI filter, the same screws 13A that are used to mechanically fix the capacitor 4 are used. For this purpose, electrical contact surfaces of the EMI filter are exposed on the side walls of the holes 13 in the mounting section 4C of the capacitor housing 4A. The contact surfaces are contacted by the metal screws 13A and electrically connected to the heat sinks 2 and 3, respectively.

[0169] The capacitor 4 has an input and an output current connection.

[0170] A high voltage DC connector 4D serves as the input current connection. In the present embodiment example, this is in the form of two metallic, electrically conductive tabs 4D projecting from a side surface 4E of the capacitor housing 4A. The tabs 4D may be connected to a corresponding current connector.

[0171] The busbar 12 described above serves as the output current connection.

[0172] To measure the input or output current, in some embodiments, appropriate sensors are attached.

[0173] Preferably, an output current sensor is used. For example, an output current sensor is attached to the tabs 11, which represent the external contacts of the semiconductor power modules 5.

[0174] FIG. 3 shows the semiconductor power modules 5 in detail. The semiconductor power modules 5 comprise a main body 5A that includes semiconductor electronics.

[0175] Furthermore, thermally conductive layers 5C are applied to the underside 5B of the semiconductor power modules 5. These are, for example, TIM (Thermal Interface Material) pastes or thermally conductive foams. The thermally conductive layer 5C has a highly viscous state and improves thermal conduction between the semiconductor power module 5 and the adjacent heat sinks 2/3. A thermally conductive layer 5C may also be applied to the top side 5D of the module 5.

[0176] Three tabs 11 are provided at the rear of each of the semiconductor power modules 5 for electrical contact with the capacitor 4. A first section 11A of the tabs is made parallel to the main body 5A of the module 5. A second section 11B is bent upward at a 90° angle. Thus, the tabs 11 can be easily welded to the contact surfaces of the busbar 12 of the capacitor 4 provided for this purpose.

[0177] On the front side of each of the modules 5, there are tabs 7 for making electrical contact with the outside and metallic pins 9 for making contact with the controller boards 10. Furthermore, the modules 5 comprise output current sensors 14 mounted near the front side on the bottom side 5B of the main body 5A.

[0178] Furthermore, the modules 5 have grooves 5E on the front and rear sides. The grooves 5E are pronounced as semicircular recesses on the outer circumference of the modules 5. The positions of the 2 grooves 5E symmetrically attached to the front and rear sides of the modules 5 differ.

[0179] The grooves 5E match corresponding lugs on the edge surfaces of the recesses in the heat sink 2 or 3. Thus, a desired orientation of the modules 5 when inserted into the recesses can be achieved via the grooves 5E. In addition, however, the desired orientation is also specified by the contacting elements present, such as the tabs 7 or 11 and the pins 9.

[0180] As an alternative to lugs, the recess in the heat sink may include pins that fit into the grooves 5E so that the modules 5 can be mounted with a snug fit in the recess.

[0181] The semiconductor power modules 5 are embedded with a precise fit in the associated recesses in the heat sinks 2/3 and mechanically fastened by pressing them in when tightening the screw connections 13A between the heat sinks. Thus, no additional components are required for mechanical assembly of the semiconductor power modules 5. This simplifies the assembly process.

[0182] FIG. 4 shows an embodiment of a heat sink as used in the first embodiment. In the first embodiment, the first heat sink 2 and the second heat sink 3 are designed in the same way. Thus, both heat sinks can be manufactured in one manufacturing process.

[0183] A distinction is made between an inner surface 21, in which recesses 23 are provided to accommodate the semiconductor power modules 5, and an outer surface 22.

[0184] The present heat sink 2 includes three recesses 23 in its inner surface 21, which are shaped such that a semiconductor power module 5 fits exactly into one of the recesses. Lugs 24 are provided on the outer periphery of the recesses 23, which fit into corresponding grooves on the outer sides of the modules 5. The lugs and grooves serve on the one hand to mechanically fix the modules 5 and on the other hand to ensure that the modules 5 are installed in the correct orientation in the recesses 23.

[0185] The heat sinks are, for example, aluminum parts. The heat sinks 2/3 comprise flow channels through which a cooling liquid such as water can flow and thus dissipate heat from the system.

[0186] Furthermore, both heat sinks 2 and 3 contain holes 13 for receiving screws 13A, which mechanically fix the heat sinks 2/3 to each other and to the capacitor 4.

[0187] FIG. 5 shows a second embodiment of the inverter system 1.

[0188] The second embodiment again comprises a first heat sink 2, a second heat sink 3, and a capacitor 4.

[0189] Features of the second embodiment similar to those of the first embodiment are not described again.

[0190] In the present embodiment, the capacitor 4 is the lowest component, which may be fixed on another assembly, and on which the heat sinks 2/3 are applied. For example, the entire assembly may be fixed on a motor.

[0191] Unlike in the first embodiment, the capacitor 4 in the second embodiment does not have a mounting section 4C with a widened base area. The base area of the entire capacitor housing 4A has the same dimensions as the base areas of the heat sinks 2 and 3, respectively.

[0192] Furthermore, in contrast to the first embodiment example, the screws 13A are inserted from the side of the first heat sink 2. At least the holes 13 in the mounting section 4C of the capacitor 4 comprise mating threads in which the screws 13 can be tightened and thus fixed.

[0193] In the present embodiment, the high voltage DC connector 4 is attached to the underside of the capacitor housing 4A, which faces the heat sinks 2/3. An input current can be connected directly here.

[0194] The electrical contact between the capacitor element or EMI filter and the semiconductor power module 5 is achieved here by pressure contacts 15.

[0195] For this purpose, pressure contacts 15 containing an electrically conductive material, preferably a conductive metal, are provided on the upper side of the capacitor 4. The contacts 15 can be designed, for example, as springs or compact pins.

[0196] When assembling the inverter system 1, the second heat sinks 3 are placed on the top of the capacitor housing 4A. The second heat sinks 3 include through holes 16 into which the pressure contacts 15 can be inserted. To avoid electrical current flow between the pressure contacts 15 and the heat sink 3 in the process, the pressure contacts 15 are surrounded by an insulating plastic sheath. Alternatively, the inner walls of the through holes 16 can be coated with an insulating plastic sheath.

[0197] When the semiconductor power module 5 is embedded in the recess 23 provided for this purpose, the module 5 is positioned such that contact surfaces 17 are directly exposed on the pressure contact 15. The contact surfaces 17 may be surfaces of the metal tabs 11 or may be located directly on the main body 5A of the module 5. In this case, metal tabs 11 are not required.

[0198] Such a module 5, whose contact surfaces 17 are positioned directly on the main body 5A, is shown in FIG. 6.

[0199] The recess 23 for accommodating the semiconductor power module 5 is here completely implemented in the second heat sink 3. This allows the semiconductor power module to be easily embedded in the recess 23. In contrast, no recess is provided in the first heat sink 3.

REFERENCE SIGN

[0200] 1 electrical inverter system [0201] 2 first heat sink [0202] 21 inner surface of the heat sink [0203] 22 outer surface of the heat sink [0204] 23 recesses [0205] 24 lugs [0206] 3 second heat sink [0207] 3A front side of the heat sink [0208] 3B back side of the heat sink [0209] 4 capacitor [0210] 4A capacitor housing [0211] 4B holding pin [0212] 4C mounting section [0213] 4D high Voltage DC Connector [0214] 4E side surface of the capacitor [0215] 5 semiconductor power module [0216] 5A power module main body [0217] 5B bottom side of the power modules [0218] 5C thermally conductive layers [0219] 5D top side of the power modules [0220] 5E grooves [0221] 6 opening between the heat sinks [0222] 7 front metal tabs [0223] 8A external contacts [0224] 8B metal screw [0225] 8C supporting part [0226] 9 pins [0227] 10A controller board [0228] 10B gate driver board [0229] 11 rear metal tabs [0230] 11A first section [0231] 11B second section [0232] 12 busbar [0233] 13 holes [0234] 13A screws [0235] 14 output current sensor [0236] 15 pressure contacts [0237] 16 through hole [0238] 17 contact surface