DRIVE, FEDERATED WITH A CONVERTER

Abstract

The invention relates to a rectifier, said rectifier having a lower part and a cover part placed on the lower part, and a cooling element at least partly enclosing the cover part.

Description

[0001] drive, comprising an inverter

[0002] Description:

[0003] The invention relates to a drive comprising a converter.

[0004] It is generally known that a drive system has an electric motor powered by an inverter.

[0005] US 5 901 040 A describes a heat sink and Faraday cage for a semiconductor module as the closest state of the art.

[0006] A motor control system with a cooling arrangement is known from US 5 508908 A.

[0007] From EP 2 270961 A2 an electric motor with a frequency converter upstream is known.

[0008] A converter motor is known from DE 102008 007 825 A1.

[0009] A cooling arrangement is known from DE 102007 014 713 B3.

[0010] The invention is therefore based on the objective of further developing a drive that is as compact as possible and has a long service life.

[0011] According to the invention, the problem is solved by the features specified in claim 1.

[0012] Important features of the invention in the drive comprising a converter are that the converter has a lower part and a cover part mounted thereon, wherein a heat sink at least partially surrounds the cover part and / or is placed on the cover part and / or has leg areas that are spaced apart from each other, and a yoke area that is connected to each of the leg areas, wherein the yoke area at least partially covers a first side of the cover part and each leg area at least partially covers a different side of the cover part, in particular wherein a thermal barrier, in particular an insulating means, is arranged between the heat sink and the cover part.

[0013] An advantage of this design is the efficient heat dissipation. The inverter's power electronics can be cooled via the heat sink, and the signal electronics via the cover. Both the cover and the heat sink are made of metal, preferably aluminum. However, since the heat flow generated by the signal electronics is lower than that of the power electronics, the cover can alternatively be made of cast steel.

[0014] Due to the large size of the heat sink, which extends over several sides of the cover, efficient heat dissipation is achieved, resulting in a compact inverter design. Furthermore, the heat dissipation of the signal electronics to the environment via the cover and the separate heat dissipation of the power electronics, particularly the power module, to the environment via the heat sink contributes to a long service life. This is because the thermal load on the signal electronics components is reduced, thus extending their lifespan.

[0015] In a preferred embodiment, the yoke area is essentially flat and at least partially covers the cover on the side facing away from the electric motor. It is advantageous that the heat sink, with its yoke area, rests at least partially flush against the cover. This allows for compact heat dissipation.

[0016] In a preferred embodiment, the three leg sections are angled, particularly perpendicularly, at the yoke area. It is advantageous that the leg sections laterally cover at least part of the cover. This enables efficient heat dissipation from the power electronics in various mounting directions. In a preferred embodiment, each leg section extends parallel to the normal direction of the flat yoke area, particularly away from the electric motor. It is advantageous that the cover can be enclosed laterally on three sides. This enables efficient heat dissipation.The thermal barrier between the cover and the heat sink allows the heat sink to dissipate heat to the surrounding environment. The outer surface of the heat sink is accessible to the environment on several differently oriented sides, while the cover still has open surface areas facing the environment. A smaller exposed surface area of ​​the cover is sufficient because the signal electronics generate less heat than the power electronics. The cover does not need to have cooling fins, but the heat sink is preferably equipped with cooling fins.

[0017] In an advantageous embodiment, each leg section at least partially covers a side of the cover section that differs from the first side and from the sides covered by the other leg sections. It is advantageous that the leg sections cannot be stacked on top of each other, but rather the cover section is always positioned between each pair of leg sections. Thus, the heat sink surrounds the cover section. The heat sink can therefore only be removed from the cover section in a single direction, perpendicular to the normal direction of the yoke section and opposite to the insertion direction, i.e., parallel to the normal direction of the yoke section.

[0018] In an advantageous embodiment, the B-side of the cover part, i.e., the side of the cover part furthest from the load-driving end of the rotor shaft protruding from the stator housing of the electric motor, is not covered by the heat sink. The advantage here is that one side of the cover part remains free, thus facilitating easy heat dissipation.

[0019] In an advantageous embodiment, the lower part and the cover part connected to the lower part enclose a space in which a circuit board assembly is arranged. This assembly is equipped with at least one heat-generating component, in particular signal electronics of the inverter, and with a power module of the inverter. The power module is thermally connected to the heat sink, and the component is thermally connected to the cover part. An advantage of this design is that the signal electronics are cooled separately from the power electronics. This allows for different temperature levels, with the signal electronics operating at a first temperature level and the power module at a second.

[0020] In an advantageous embodiment, the thermal barrier comprises an insulating material arranged on a surface area of ​​the heat sink facing the cover. The advantage here is that the insulating material provides both electrical and thermal insulation. This allows the power module to be electrically connected to the heat sink in such a way that the heat sink is at the electrical potential present at the power module, and the signal electronics also share a common potential with the cover. Galvanic isolation is implemented on the circuit board between the signal electronics and the power module. Thus, the cover and the heat sink are also galvanically isolated.

[0021] In an advantageous embodiment, the thermal barrier comprises thermally and electrically insulating layers or materials intended for insulating fasteners, wherein the fasteners connect the heat sink to the cover part, in particular wherein the fasteners are screws. An advantage of this is that while mechanical fastening is achieved by the fasteners, no electrical or thermal connection is established.

[0022] In an advantageous embodiment, a filler material is arranged between the component and the cover part, which is metallurgically bonded to both the component and the cover part. The filler material comprises ceramic particles and / or is thermally conductive, and in particular, its thermal conductivity differs from that of thermal paste by less than a factor of 2. An advantage of this is that the thermal resistance between the component and the cover part is extremely low, thus enabling efficient heat conduction through the filler material. This allows for heat dissipation from the component via the cover part, even though a gap exists between the component and the cover part. In contrast to the use of thermal paste, the component is not pressed directly against the cover part, but rather has a gap that can be bridged by the filler material.When the circuit board, on which the component is mounted, is attached to the cover part, the filling material is elastically deformed.

[0023] In an advantageous embodiment, the filler material is produced in multiple pieces, with each component mounted on the printed circuit board assembly, particularly on a circuit board of the assembly, being assigned a specific piece of filler material, particularly a heat-generating component, and in particular, being uniquely assigned, wherein the area of ​​the perpendicular projection of the filler material piece into the plane of the circuit board exceeds the area of ​​the perpendicular projection of the component into the plane of the circuit board by less than 50%. It is advantageous that, during manufacturing, filler material can be assigned to each component by means of a dispersion device. Therefore, the filler material can be used in a material-saving manner, and yet each heat-generating component of the signal electronics mounted on the circuit board can be efficiently dissipated via the cover part.

[0024] In an advantageous embodiment, the filling material is designed to be elastic such that thermally induced changes in the distance between the cover part and the component during operation of the inverter can be compensated for within the elastic deformation range of the filling material. An advantage of this is that the temperature rise occurring during operation does not impair the thermally conductive connection provided by the filling material.

[0025] In an advantageous embodiment, thermal paste is arranged between the heat sink and the power module. It is advantageous that the power module is pressed against the heat sink and that the thermal paste reduces the thermal resistance, allowing it to penetrate even very small recesses in the contact surface between the filler material and the cover or component. In an advantageous embodiment, the cover and / or the insulating material has a recess through which the power module and / or the heat sink protrudes. It is advantageous that the power module is mounted on the circuit board and the circuit board is surrounded by the cover, yet the heat can still be dissipated separately to a heat sink located outside the cover. In particular, the cover is positioned between the heat sink and the circuit board.

[0026] In an advantageous embodiment, the insulating material is arranged between the heat sink and the cover part, wherein the insulating material is tightly connected to both the heat sink and the cover part, in particular wherein the insulating material is made of a plastic and / or acts as a thermal barrier and / or is made of an electrically insulating material. It is advantageous that the insulating material seals the area in which the power module is arranged from the environment. Although the heat sink is spaced apart from the cover part, the insulating material fills the space formed between the heat sink and the cover part, surrounding the recess in the cover part through which the power module protrudes.

[0027] In an advantageous embodiment, the insulating material has a collar area surrounding the power module, which adjoins the printed circuit board. The advantage here is that the power module can be arranged with improved thermal and electrical isolation from the signal electronics components mounted on the printed circuit board.

[0028] In an advantageous embodiment, the drive comprises an electric motor on which the inverter is arranged. It is advantageous that the inverter, in particular the power electronics, especially comprising the power module, can preferably be cooled on the side of the inverter facing away from the electric motor.

[0029] In an advantageous embodiment, the heat sink has cooling fins on its outer surface, which are curved on the side of the heat sink facing away from the electric motor in such a way that they extend from one side surface to at least two other side surfaces, and in particular to three side surfaces. The advantage of this is that, with different mounting orientations, a cooling airflow can be generated along the cooling fins, and water can drain away, thus preventing it from accumulating between the cooling fins.

[0030] In an advantageous embodiment, an additional fan is arranged on the heat sink, in particular wherein the airflow conveyed by the fan flows at least partially along the surface of the heat sink. An advantage of this is that more efficient cooling can be achieved. The fan can be designed with a fan shroud which can be connected to the heat sink in such a way that the conveyed cooling airflow flows along the cooling fins without significant losses.

[0031] Further advantages arise from the dependent claims. The invention is not limited to the combination of features of the claims. For those skilled in the art, further meaningful combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent, in particular from the problem statement and / or the problem arising from a comparison with the prior art.

[0032] The invention will now be explained in more detail with reference to schematic illustrations:

[0033] Figure 6 shows a drive according to the invention, comprising an electric motor 61 with inverter, which has a lower part 60 and an upper part 2 placed on it with a cooling sink 3 placed over it.

[0034] Figure 1 shows a schematic cross-section through the converter.

[0035] Figure 2 shows the inverter exploded in an oblique view.

[0036] Figure 3 shows the upper part 2 with the attached heat sink 3 in an oblique view.

[0037] Figure 4 shows the upper part 2 in an oblique view.

[0038] Figure 5 shows a heat sink 3 on its own in an oblique view from the electric motor 61.

[0039] Figure 7 shows an optional insulating material 4, arranged between the upper part 2 and the heat sink 3, in an oblique view.

[0040] As shown in the figures, the drive has an electric motor 61, the rotor shaft of which is non-rotatably connected to a fan which is covered by a fan hood 62.

[0041] An inverter is arranged on the electric motor 61, which has a lower part 60 and a cover part 2, which is placed on the lower part 60 and tightly connected to the lower part 60. A heat sink 3 is attached to the cover part 2.

[0042] The lower part 60 is connected to the stator housing of the electric motor 61, with the lower part 60 and the stator housing each having a recess through which the winding wire of the stator winding is guided from the stator winding into the interior space enclosed by the lower part 60 and the cover part 2. In this interior space, a connector part, mounted on a first circuit board of a circuit board assembly attached to the lower part 60 or the cover part 2, is plugged into a corresponding mating connector part mounted on a second circuit board of the circuit board assembly, the second circuit board being attached to the cover part 2. The stator winding is preferably electrically connected to contacts of the first connector part.

[0043] The first and / or second circuit board is equipped with the inverter's signal electronics, which are capable of generating pulse-width modulated control signals for the semiconductor switches of the inverter's power electronics. The semiconductor switches are integrated into a power module 6, the terminals of which are electrically connected to conductors on the first circuit board. On the side of the power module 6 facing away from its terminals, the power module 6 is pressed onto a preferably finely machined contact surface of the heat sink 3, so that the power module 6 makes contact with the heat sink 3 at this contact surface. Preferably, this contact is achieved by a screw passing through the power module, the screw head of which presses the power module 6 towards the heat sink because the threaded portion of the screw is at least partially screwed into a threaded bore in the heat sink.

[0044] Thermal paste is preferably provided in the area of ​​the contact surface, so that the thermal resistance between power module 6 and heat sink 3 is reduced.

[0045] The semiconductor switches of the power module 6 are arranged in parallel half-bridges, this parallel connection being supplied with a DC voltage. Thus, the preferably three half-bridges form an inverter which provides the electric motor 61 with a preferably three-phase AC voltage.

[0046] The lower part 60 is tightly connected to the stator housing. The cover part 2 is also tightly connected to the lower part 60.

[0047] The cover part 2 has a recess on its side facing away from the electric motor, in particular the stator housing, through which a portion of the heat sink 3 projects into the interior space up to the power module 6. The power module 6 is preferably arranged within the interior space. The cover part 2 is preferably made of metal, in particular die-cast aluminum.

[0048] The heat sink 3 is preferably made of metal, in particular aluminum die-casting.

[0049] Although the heat sink 3 is thermally connected to the power module 6, electrical and thermal insulation is arranged between the heat sink 3 and the cover part 2. Metallic connecting elements that join the heat sink 3 to the cover part 2 are connected to one or more plastic parts positioned between the cover part 2 and the heat sink 3. The insulation includes not only these connecting elements but also an insulating element 4, which is shown in more detail in Figure 2 and covers the inner surface of the heat sink 3 facing the cover part 2.

[0050] The insulating element 4 is made of an electrically and thermally insulating material, such as plastic or the like. It need not be designed as a separate part, but may also be formed as a composite part with the heat sink 3, in particular, for example, as a plastic coating or other layer bonded to the heat sink 3.

[0051] On the circuit board arrangement 5, in particular the second circuit board, heat-generating components are mounted, which are thermally connected to the cover part 2 by means of filler material 1.

[0052] Thus, the signal electronics of the inverter are cooled via the cover part 2 and the power electronics of the inverter via the heat sink 3.

[0053] The filler material 1, located between the respective heat-generating component mounted on the second circuit board and the cover part 2, is metallurgically bonded to both the cover part 2 and the respective component. Furthermore, the filler material 1 is elastic enough that the changes in length between the cover part 2 and the second circuit board caused by the thermal movements occurring during operation of the drive are within the elastic range of the filler material 1 and can therefore be accommodated by the filler material 1, in particular through elastic deflection of the filler material 1. The thermal conductivity of the filler material 1 differs from that of thermal paste by less than a factor of 2.

[0054] As shown in Figure 5, the heat sink has three leg sections 51, which are spaced apart from each other but are all connected by a yoke section 50. The yoke section 50 is preferably flat and covers the cover part 2 on its side facing away from the electric motor 61.

[0055] The three leg sections 51 are arranged at an angle on the yoke section 50 and each extends parallel to the normal direction of the flat yoke section 50, in particular away from the electric motor 61.

[0056] Each of the leg areas 51 also covers at least part of one side of the lid part 2.

[0057] Thus, only the B-side side, i.e., the side of the cover part 2 which is furthest away from the load-driving end of the rotor shaft protruding from the stator housing of the electric motor 61, is not covered by the heat sink 3.

[0058] The lid part 2 together with the lower part 60 forms an essentially cuboid housing.

[0059] Due to the mutual spacing of the leg areas 51 from each other, the corner areas of the cover part 2 are not covered by the heat sink 3 and thus screws can be actuated which are arranged in the respective corner area and pass through the cover part 2 and are screwed with their threaded area into threaded bores of the lower part 60, so that the screw heads of these screws press the cover part 2 against the lower part 60.

[0060] As shown in Figure 2, the insulating material 4 covers the inside of the heat sink 3. Thus, the heat sink 3 is electrically and thermally insulated from the cover part 2. The insulating material 4, like the cover part, has a recess through which the power module 6 protrudes and rests on the contact surface of the heat sink 3, with thermal paste interposed between them.

[0061] The heat sink 3 has cooling fins on its outer surface. These are curved on the side of the heat sink 3 facing away from the electric motor 61 in such a way that they extend from one side surface to at least two other side surfaces, in particular to three side surfaces.

[0062] The filler material 1 is preferably multi-piece. Each component mounted on the printed circuit board is assigned a piece of filler material. During the manufacture of the drive, a liquid, paste-like material is applied piecewise to the component or, alternatively, to the inside of the cover part 2 using a dispersion device. When the printed circuit board and the cover part 2 are joined, the material hardens and thus forms the respective filler material piece. This filler material piece, however, remains elastically deformable and is metallurgically bonded to the respective component and the cover part 2. The filler material piece only partially covers the respective component. In particular, the area of ​​the perpendicular projection of the filler material piece into the plane of the printed circuit board exceeds the area of ​​the perpendicular projection of the component into the plane of the printed circuit board by less than 50%.Thus, each heat-generating component mounted on the circuit board is uniquely assigned to a specific piece of filler material.

[0063] According to the invention, the drive is designed as an inverter motor, in particular such that the inverter has a heat sink 3 which surrounds a cover part 2 of the inverter. Furthermore, pieces of filler material are present between components of the signal electronics and the cover part. The power module 6 projects through a recess in the cover part 2 and is thermally connected to the heat sink 3. An electrically and thermally effective insulating material is located between the heat sink 3 and the cover part 2.

[0064] As shown in Figure 7, the optional insulating material 4 has leg sections 70 corresponding to the leg sections 51, so that the insulating material 4 also rests on the inside of the leg sections 51, thus reducing heat transfer and increasing insulation strength. Furthermore, a collar section 71 is formed on the insulating material 4, which extends around the recess of the power module 6 penetrated by the power module, and in particular, surrounds the power module 6 on its sides. The extension of the collar section 71 in the insertion direction of the power module 6, and in particular in the normal direction to the circuit board 5, is such that the collar section 71 reaches right up to the circuit board 5, and in particular, abuts it. Thus, the thermal barrier and insulation of the power module 6 are optimized.

[0065] In further embodiments of the invention, an additional fan is attached to the heat sink 3, so that the airflow conveyed by the fan is at least partially directed along the surface of the heat sink 3. Preferably, a further fan shroud is provided, which is attached to the heat sink 3, to improve the direction of the conveyed airflow.

[0066] Reference symbol list

[0067] 1 Filling material 2 Lid part

[0068] 3 heat sinks

[0069] 4 Insulating materials, in particular electrically insulating and sealing connecting materials

[0070] 5. Circuit board arrangement

[0071] 6 Power module 50 Yoke area

[0072] 51 Thigh area

[0073] 60 Lower part

[0074] 61 Electric motor

[0075] 62 Fan hood 70 Leg area

[0076] 71 wraparound collar

Claims

Patent claims:

1. Drive comprising a converter, wherein the converter has a lower part and a cover part placed thereon, characterized in that a heat sink at least partially surrounds the cover part and / or is placed on the cover part and / or has leg areas that are spaced apart from each other, and a yoke area that is connected to each of the leg areas, in particular wherein the yoke area at least partially covers a first side of the cover part and each leg area at least partially covers a different side of the cover part, in particular wherein a thermal barrier is arranged between the heat sink and the cover part.

2. Drive according to claim 1, characterized in that the drive has an electric motor, wherein the yoke area is essentially flat and at least partially covers the cover part on its side facing away from the electric motor.

3. Drive according to one of the preceding claims, characterized in that the three leg regions are arranged at an angle, in particular at a perpendicular angle, on the yoke region, and / or that the yoke region is essentially planar and each of the leg regions extends parallel to the normal direction of the yoke region, in particular towards the electric motor.

4. Drive according to one of the preceding claims, characterized in that each of the leg sections at least partially covers a side of the cover part that differs from the first side and from the sides covered by the other leg sections, in particular, each of the leg sections at least partially covers a different side of the cover part, and / or that the B-side side of the cover part, i.e., the side of the cover part that is furthest away from the load-driving end of the rotor shaft protruding from the stator housing of the electric motor, is not covered by the heat sink.

5. Drive according to one of the preceding claims, characterized in that the lower part and the cover part connected to the lower part surround a space in which a circuit board arrangement is arranged, which is equipped with at least one heat-generating component, in particular signal electronics of the converter and with a power module of the converter, wherein the power module is thermally connected to the heat sink and the component is thermally connected to the cover part.

6. Drive according to one of the preceding claims, characterized in that a thermal barrier comprises an insulating means which is arranged on a surface area of ​​the heat sink facing the cover part and / or that the insulating means is arranged between the heat sink and the top part.

7. Drive according to claim 6, characterized in that the thermal barrier comprises thermally and electrically insulating layers or materials provided for insulating fastening means, wherein the fastening means connect the heat sink to the cover part, in particular wherein the fastening means are screws.

8. Drive according to one of the preceding claims, characterized in that between a component or the respective component arranged on a printed circuit board arrangement, in particular a printed circuit board of the printed circuit board arrangement, filler material is arranged which is metallurgically bonded to both the component and the cover part, wherein the filler material comprises ceramic particles and / or is thermally conductive, in particular wherein the thermal conductivity of the filler material differs from the thermal conductivity of thermal paste by less than a factor of 2.

9. Drive according to one of the preceding claims, characterized in that the filling material is multi-piece, wherein a respective component, in particular a heat-generating component, mounted on the circuit board arrangement, in particular on a circuit board of the circuit board arrangement, is assigned a respective piece of filling material, in particular is uniquely assigned, in particular wherein the area of ​​the perpendicular projection of the filling material piece into the circuit board plane exceeds the area of ​​the perpendicular projection of the component into the circuit board plane by less than 50%.

10. Drive according to one of the preceding claims, characterized in that one or the filling material is designed to be elastic in such a way that those changes in the distance between the cover part and the component which are thermally induced during operation of the inverter can be compensated in the elastic range of deformation of the filling material, in particular wherein the distance between the cover part and the component is greater than two millimeters, in particular greater than five millimeters.

11. Drive according to one of the preceding claims, characterized in that thermal paste is arranged between the heat sink and the power module.

12. Drive according to one of the preceding claims, characterized in that the cover part and / or the insulating means has a recess through which the power module and the heat sink protrude.

13. Drive according to one of the preceding claims, characterized in that the insulating means is arranged between the heat sink and the cover part, wherein the insulating means is both tightly connected to the heat sink and tightly connected to the cover part, in particular wherein the insulating means is made of a plastic and / or acts as a thermal barrier and / or is made of an electrically insulating material.

14. Drive according to one of the preceding claims, characterized in that the insulating material has a collar area surrounding the power module, which adjoins the circuit board.

15. Drive according to one of the preceding claims, characterized in that the drive has an electric motor on which the inverter is arranged, and / or that the heat sink has cooling fins on its outside which are curved on the side of the heat sink 3 facing away from the electric motor in such a way that they extend from one side surface to at least two other side surfaces, in particular to three side surfaces, and / or that an additional fan is arranged on the heat sink, in particular wherein the airflow conveyed by the fan flows at least partially along the surface of the heat sink.