DRIVE, FEDING A CONVERTER

Description

[0001] The invention relates to a drive comprising a converter.

[0002] It is generally known that a drive system has an electric motor powered by an inverter.

[0003] US patent 5 901 040 A describes a heat sink and Faraday cage for a semiconductor module.

[0004] A motor control system with a cooling arrangement is known from US patent 5,508,908 A.

[0005] From EP 2 270 961 A2 an electric motor with a frequency converter upstream is known.

[0006] A converter motor is known from DE 10 2008 007 825 A1.

[0007] A cooling arrangement is known from DE 10 2007 014 713 B3.

[0008] From the EP 1 701 431 A1 A terminal box for an electric motor is known.

[0009] From the EP 1 176 706 A2 A frequency converter with a housing consisting of an upper part and a lower part is known.

[0010] From the DE 10 2005 037 488 A1 A device is known.

[0011] The invention is based on the objective of further developing a drive that is as compact as possible and has a long service life.

[0012] According to the invention, the problem is solved by the features specified in claim 1.

[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 through the cover to the surrounding environment, and the separate heat dissipation of the power module via the heat sink to the surrounding environment, ensures 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 at the yoke area, particularly at a perpendicular angle. 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.

[0017] In an advantageous embodiment, each leg extends parallel to the normal direction of the planar yoke area, particularly away from the electric motor. It is advantageous that the cover can be grasped laterally on three sides. This enables efficient heat dissipation. Because a thermal barrier is arranged between the cover and the heat sink, heat dissipation from the heat sink to the environment is possible, with the outer surface of the heat sink being accessible to the environment on several differently oriented sides, while the cover still also has open surface areas facing the environment. A smaller free 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 designed with cooling fins.

[0018] According to the inventionEach leg section covers at least a portion of the cover, differing from the first side and from the sides covered by the other leg sections. A key advantage is that the leg sections cannot be stacked on top of each other; instead, the cover is always positioned between each pair of leg sections. Thus, the heat sink completely surrounds the cover. The heat sink can therefore only be removed from the cover in one 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.

[0019] 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.

[0020] According to the inventionThe lower part and the cover part connected to it enclose a space containing a circuit board assembly. This assembly includes at least one heat-generating component, signal electronics for the inverter, and a power module for 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 one temperature level and the power module at another.

[0021] According to the inventionThe thermal barrier comprises an insulating material located on a surface area of ​​the heat sink facing the cover. A key advantage 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. Therefore, the cover and the heat sink are also galvanically isolated.

[0022] 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.

[0023] According to the invention Filling material is arranged between the component and the lid part, which is bonded to both the component and the lid part. The filler material comprises ceramic particles and is thermally conductive, and 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 is extremely low, thus enabling efficient heat transfer through the filler material. This allows for heat dissipation from the component via the cover, even though a gap exists between the component and the cover. Unlike when using thermal paste, the component is not pressed directly against the cover but has a gap that is bridged by the filler material. When the circuit board on which the component is mounted is attached to the cover, the filler material is elastically deformed.

[0024] 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.

[0025] 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.

[0026] In a preferred embodiment, thermal paste is applied between the heat sink and the power module. The advantage here is that the power module is pressed against the heat sink and 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 part or component.

[0027] According to the invention, the lid part has a recess through which the power module and the heat sink protrude.

[0028] An advantage of this design is that the power module is mounted on the circuit board, which is surrounded by the cover, yet the heat can still be dissipated separately to a heat sink located outside the cover. Specifically, the cover is positioned between the heat sink and the circuit board.

[0029] According to the invention The insulating material is positioned between the heat sink and the lid part. The insulating material is tightly bonded to both the heat sink and the cover, and is made of a plastic material that acts as a thermal barrier and / or is made of an electrically insulating material. An advantage of this design is that the insulating material seals the area in which the power module is located from the environment. Although the heat sink is spaced apart from the cover, the insulating material fills the gap formed between the heat sink and the cover, extending around the recess in the cover through which the power module protrudes.

[0030] According to the inventionThe insulating material features a collar area surrounding the power module, adjacent to the circuit board. This offers the advantage of improved thermal and electrical isolation between the power module and the signal electronics components mounted on the circuit board.

[0031] In an advantageous embodiment, the drive comprises an electric motor on which the inverter is arranged. It is advantageous that the inverter, comprising the power module, can be cooled, preferably on the side of the inverter facing away from the electric motor.

[0032] 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.

[0033] 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.

[0034] The invention will now be explained in more detail with reference to schematic illustrations: In the Figure 6 A drive according to the invention is shown, comprising an electric motor 61 with inverter, which has a lower part 60 and a cover part 2 placed on it with a cooling sink 3 placed over it.

[0035] In the Figure 1 A cross-section through the converter is schematically sketched.

[0036] In the Figure 2The inverter is shown exploded in an oblique view.

[0037] In the Figure 3 The lid part 2 with the attached heat sink 3 is shown in an oblique view.

[0038] In the Figure 4 The lid part 2 is shown in an oblique view.

[0039] In the Figure 5 A heat sink 3 is shown on its own in oblique view from the electric motor 61.

[0040] In the Figure 7 is an optional insulating medium 4, arranged between the cover part 2 and the heat sink 3, shown in oblique view.

[0041] 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.

[0042] 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.

[0043] The lower part 60 is connected to the stator housing of the electric motor 61, wherein the lower part 60 and the stator housing each have a recess through which the winding wire of the stator winding is guided from the stator winding into the interior area which is surrounded by the lower part 60 and cover part 2.

[0044] In this interior area, a connector part, mounted on a first printed circuit board of a printed 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 printed circuit board of the printed circuit board assembly, the second printed circuit board being attached to the cover part 2. The stator winding is preferably electrically connected to contacts of the first connector part.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] The lower part 60 is tightly connected to the stator housing. The cover part 2 is also tightly connected to the lower part 60.

[0049] The cover part 2 has a recess on its side facing away from the electric motor, in particular the stator housing, through which a section of the heat sink 3 projects into the interior area up to the power module 6. The power module 6 is preferably arranged within the interior area.

[0050] The lid part 2 is preferably made of metal, in particular aluminum die-casting.

[0051] The heat sink 3 is preferably made of metal, in particular aluminum die-casting.

[0052] 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 located in Figure 2 The insulating material 4 is shown in more detail and covers the inner surface of the heat sink 3 facing the cover part 2. The insulating material 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.

[0053] 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.

[0054] 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.

[0055] 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 strokes occurring during operation of the drive lie within the elastic range of the filler material 1, and are therefore absorbed by the filler material 1, in particular by elastic deflection of the filler material 1.

[0056] The thermal conductivity of the filler material 1 differs from the thermal conductivity of thermal paste by less than a factor of 2.

[0057] As in Figure 5As shown, 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.

[0058] 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.

[0059] Each of the leg areas 51 also covers at least part of one side of the lid part 2.

[0060] 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.

[0061] The lid part 2 together with the lower part 60 forms an essentially cuboid housing.

[0062] 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.

[0063] As in Figure 2 As shown, 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.

[0064] The insulating material 4, like the lid 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.

[0065] 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.

[0066] 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 piece of filler material. This respective piece of filler material remains elastically deformable and is metallurgically bonded to the respective component and the cover part 2. The piece of filler material 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.

[0067] 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.

[0068] As in Figure 7As shown, the insulating material 4 has leg regions 70 corresponding to the leg regions 51, so that the insulating material 4 also rests on the inside of the leg regions 51, thus reducing heat transfer and increasing insulation strength. Furthermore, a collar region 71 is formed on the insulating material 4, which extends around the recess of the power module 6 penetrated by the power module, and thus surrounds the power module 6 on its sides. The extension of the collar region 71 in the insertion direction of the power module 6, and in particular in the normal direction to the circuit board 5, is so extensive that the collar region 71 reaches right up to the circuit board 5, i.e., abuts it. Thus, the thermal barrier and insulation of the power module 6 are optimized.

[0069] 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. Reference symbol list

[0070] 1 Filling material 2 Cover part 3 Heat sink 4 Insulating material, in particular electrically insulating and sealing connecting material 5 Circuit board assembly 6 Power module 50 Yoke area 51 Leg area 60 Base part 61 Electric motor 62 Fan cover 70 Leg area 71 Circumferential collar

Claims

1. Drive comprising a converter, wherein the converter has a bottom part (60) and a cover part (2) mounted thereon, wherein a cooling member (3) at least partly encompasses the cover part (2) and has leg regions (51, 70), which are spaced apart from one another, and a yoke region (50), which is connected to each of the leg regions (51, 70), wherein the yoke region (50) at least partly covers a first side of the cover part (2), and each leg region (51, 70) at least partly covers a different side of the cover part (2) in each case, wherein a thermal barrier is arranged between the cooling member (3) and the cover part (2), wherein each of the leg regions (51, 70) at least partly covers a side of the cover part (2) that is different from the first side and the sides covered by the other leg regions (51, 70), i.e. each of the leg regions (51, 70) at least partly covers a different side of the cover part (2) in each case, wherein the thermal barrier comprises an insulation means (4) which is arranged on a surface region of the cooling member (3) facing the cover part (2), wherein the bottom part (60) and the cover part (2) connected to the bottom part (60) enclose a spatial region in which there is arranged a circuit board arrangement (5) to which at least one heat-generating component of signal electronics of the converter and also a power module (6) of the converter are fitted, wherein the power module (6) is connected in a heat-conducting manner to the cooling member (3), and the component is connected in a heat-conducting manner to the cover part (2), wherein filling material (1) is arranged between the cover part (2) and the at least one heat-generating component arranged on a circuit board of the circuit board arrangement (5) and is integrally bonded to both the component and the cover part (2), wherein the filling material (1) has ceramic particles and is heat-conductive, wherein the cover part (2) has a cut-out through which the power module (6) and the cooling member (3) project, wherein the insulation means (4) has a collar region which extends all around the power module (6) and which adjoins the circuit board, wherein the insulation means (4) is arranged between the cooling member (3) and the cover part (2), wherein the insulation means (4) is both tightly connected to the cooling member (3) and tightly connected to the cover part (2), wherein the insulation means (4) is made of a plastics material and acts as a thermal barrier and / or is made of a highly electrically insulating material.

2. Drive according to claim 1, characterised in that the drive has an electric motor (61), the yoke region (50) being formed to be substantially planar and at least partly covering the cover part (2) on its side facing away from the electric motor (61).

3. Drive according to any of the preceding claims, characterised in that the in particular three leg regions (51, 70) are arranged in an angled manner, in particular in a vertically angled manner, on the yoke region (50).

4. Drive according to any of the preceding claims, characterised in that the yoke region (50) is formed to be substantially planar, and each of the leg regions (51, 70) extends in parallel with the normal direction of the yoke region (50) in each case, in particular towards the electric motor (61).

5. Drive according to any of the preceding claims but at least comprising the features of claim 2, characterised in that the non-drive end of the cover part (2), i.e. that side of the cover part (2) which is the furthest away from the rotor shaft end protruding out of the stator casing of the electric motor (61) and driving the load, is not covered by the cooling member (3).

6. Drive according to any of the preceding claims, characterised in that the thermal barrier comprises thermally and electrically insulating layers or materials that are intended for insulating fasteners, the fasteners connecting the cooling member (3) to the cover part (2), the fasteners in particular being screws.

7. Drive according to any of the preceding claims, characterised in that the thermal conductivity of the filling material (1) differs from the thermal conductivity of thermal paste by less than a factor of 2.

8. Drive according to any of the preceding claims, characterised in that the filling material (1) is formed in multiple pieces, each filling material piece being assigned, in particular unambiguously assigned, to a particular component, in particular heat-generating component, fitted on the circuit board arrangement (5), in particular on a circuit board of the circuit board arrangement (5), the area of the vertical projection of the filling material piece into the circuit board plane in particular only being less than 50% greater than the area of the vertical projection of the component into the circuit board plane.

9. Drive according to any of the preceding claims, characterised in that the filling material (1) is formed to be resilient such that the changes in the distance between the cover part (2) and the component which are induced by thermal processes while the converter is in operation can be compensated for within the elastic range of the deformation of the filling material (1), the distance between the cover part (2) and the component in particular being greater than two millimetres, in particular greater than five millimetres.

10. Drive according to any of the preceding claims, characterised in that thermal paste is arranged between the cooling member (3) and the power module (6).

11. Drive according to any of the preceding claims, characterised in that the drive has an electric motor (61) on which the converter is arranged.

12. Drive according to claim 11, characterised in that the cooling member (3) has cooling ribs on its exterior, which are formed on the side of the cooling member (3) facing away from the electric motor (61) in a curved manner such that they extend from one particular side face to at least two other side faces, in particular to three side faces.

13. Drive according to any of the preceding claims, characterised in that an additional fan is arranged on the cooling member, the air stream conveyed by the fan in particular flowing at least partly along the surface of the cooling member (3).