EP1772877B1 - MF transformer with improved heat dissipation - Google Patents

Abstract

An inductive component has at least one winding and between individual layers of the winding and/or of a further winding, one or more thermal bridging intermediate insulations are arranged, in which these heat bridging intermediate insulations have a flexible, insulating foil, which are worked into the heat conductive filler material and which, in comparison to earlier intermediate, winding, or ground insulations, such as mica, polyester, polyamide, various insulating papers, mixed insulations, etc, also have various resins, casts, and injection-molded compounds of high thermal conductivity.

Description

Field of the invention

The invention relates to an inductive component, such as a transformer or a choke, but in particular a medium-frequency transformer (MF transformers) with galvanic isolation, as used for example for applications in the field of railway technology and industry.

State of the art

Transformers and chokes are essential components in electrical engineering, in industrial plant construction, in rail vehicle construction and generally in many areas of technology (including airplanes / satellites). Nevertheless, power compression has been realized in the design of transformers and chokes in the past to a limited extent. For example, known rectangular and cylindrical designs have a power to weight ratio of about 0.4-0.6 g / W at 6-12 kHz with a transmission power between 30 and 50 kVA.

A significant improvement in power weight and compression is the patent DE 102 03 246 B4 According to this invention, a significant improvement in the power density of MF transformers is achieved here with a winding.

Despite the technical advances in technical data and applications noted in the above-identified patent, further inventive advances are being made in the direction of increasing performance while retaining of designs and improved designs and manufacturing possible. For many applications, in particular in the mobile sector, but also in most industrial applications, there is a need for even higher performance with similar possible, but especially developed designs.

MF transformers, as well as other transformers and chokes for industrial and rail transport, are traditionally cooled only at the winding or at gaps with air or other media.

For the magnetic circuit, some additional cooling surfaces or indirect liquid cooling devices are installed, which can reduce the volume and weight of the transformers.

Current designs, as they are customary since the beginning of electrical engineering and built little changed, but do not allow the optimal use of the used, usually high-quality materials such as copper, aluminum or even the costly soft magnetic materials.
According to previous designs with the usual mechanisms of heat dissipation windings and cores must be constructed much larger in cross-section / volume, although the conductor cross sections of the windings, the ferrites and the Weihmagnetic materials would be physically higher load capacity.

The reason for this is the problem of how the resulting heat loss can be dissipated into the atmosphere. The heat dissipation is greatly hindered by the thermal resistances of the interlayer and coil insulation, especially in the mid-interior areas of the windings, resulting in high temperatures. Furthermore, the classes of insulation limit the currents of the transformers by fixed maximum temperatures of insulating materials, although in most cases higher Controllers of the magnetic circuit and thus higher currents and powers would be possible.

In many cases, this in turn causes the magnetic component (cores and / or yokes) to become larger. Therefore, as a rule, the conductor cross section and / or the core cross section must be increased, also because the functional curves of the magnetic materials (inter alia induction) deteriorate at high temperatures, ie. H. The core cross-sections usually have to be significantly increased, which in turn leads to higher losses due to the larger windings (longer winding lengths).

In rail technology - auxiliary converter converters (HBU) and in the converter units for the drives - the slow development of transformers and chokes becomes clear in two ways. On the one hand, the development of power electronics, semiconductors, and passive magnetic components is increasingly falling apart in terms of weight and volume. Ie. the significant reduction of the HBU or drive converter modules also does not have a desirable dynamic equivalent in the magnetic components.

On the other hand, heavy and volume-intensive transformers and chokes in rail vehicles do not cause low costs. For kg of weight and environmental costs in power converters, the costs for MF transformers amount to approx. 30-40 € / kg. The transport of these weights - in 30 years lifetime - requires per kg of weight again 100 -150 € for energy costs. For aircraft and satellites the adequate values are much higher.

Reason enough to intensively search for further inventive progress in order to further reduce the weights and volumes of MF transformers and chokes and, in addition to manufacturing costs, to ensure even more effective use of materials and to further reduce energy consumption directly and indirectly.

Due to the large dimensions and the relatively high specific weight known, even newer MF transformers and chokes the MF modules in HBUs or drive converter downstream * and upstream. However, the direct inclusion of transformers and chokes in the module constructions and the shared use of these atmospheric air cooling streams, which are usually very effective, allow drastic savings in the volume and weight of the HBU or SR containers. At present, special air / air or air / water recoolers are often required, which require additional installation space in the electrical container or converter cabinet. Exactly this technical effort can be avoided or significantly reduced.

Moreover, it is rather disadvantageous that the arrangement of MF transformers and chokes outside the HBU or SR containers or cabinets and rooms in atmospheric air usually require additional protection against moisture, dirt and stone chipping.

EP 0 882 574 A1 discloses a high thermal conductivity composite material consisting of a fibrous organic material, an inorganic filler and a resin matrix. The composite material can be used for heat dissipation in electrical components.

EP 1 530 223 A1 discloses a highly thermally conductive insulating material based on resin, which can be used in particular in inductive components to improve heat dissipation.

Presentation of the invention

The invention is based on the object in transformers and reactors, in particular MF transformers, to achieve a power compression, at least by a factor of 1.5. That is, the MF transformers or chokes according to the invention have in comparison to conventional MF transformers, with the same volume and weight, at least a factor of 1.5 greater performance, or at the same power a significantly lower volume and weight

With throttles, the possibilities of compaction are not given to the same extent, but here too remarkable savings of more than 30% in weight, volume and energy consumption during operation are to be expected by the measures according to the invention.

This object is achieved by an inductive component with the features of claims 1 and 2.

Advantageous embodiments and further preferred features of the invention are set forth in the dependent claims, the disclosure of which is hereby incorporated by reference.

With the solution according to the invention, a saving of material and reduction of MF transformer or chokes is achieved with the same performance by a drastic reduction of the internal thermal resistance between the turns - even over several primary and secondary part windings away - made. On the other hand, an effective transport of the heat loss with reduced temperature gradients from the windings is first achieved on the surfaces of transformers and chokes and then into the atmosphere.

Overall, a significant improvement in heat dissipation from the inner regions of the windings and thus a dissipation of the heat loss is achieved via increased outside temperatures of the outer surfaces / partial cooler of the transformers in the atmosphere. Additionally and alternatively, the heat flow from the windings z. B. from the "layer centers" of the windings are concentrated, and by means of heat transfer lugs inserted the heat loss on test voltage insulated heat pipes, so-called heat pipes, passed, in turn, direct the heat on metal surfaces or special cooler, which may alternatively be arranged outside the Traforaumes.

This is possible with partially considerable electrical voltage differences between primary and secondary windings, medium-voltage resistant thermal bridges, z. B. made of flexible ceramic insulation and otherwise produced insulating Wärmeleitteilen used.

On the one hand, the invention solves the problem of difficult heat transmission through the conductor insulations, or in the case of reflow / pouring of the windings through most of the insulating surfaces of the transformers or reactors. On the other hand, there was previously a mostly insufficient heat dissipation from the insulating surfaces of the winding, which also represent a considerable thermal resistance. According to the invention newly developed Wärmeleitfolien be used, which have a better thermal conductivity by a factor of 5-20 than the previously used insulation materials, and it is galvanically isolating test voltage safe thermal bridges used, which derive the heat loss much more effective from thermal focus.

Another problem to be solved was the difficult heat transmission through the intermediate insulation of the primary and secondary windings (especially the inner windings). These considerably complicate the heat flow to the outside. Physically, thermal conductivity and small conductor cross-sections usually cause little heat flow over the cable cross-sections to external connections or their surfaces. According to the invention, thermal bridge intermediate insulations are newly developed, which substantially improve the heat dissipation from the inner layers of the windings to the outer layers and to the transformer surface and make the use of auxiliary coolers arranged there with low volume very effective.

The invention is based on a novel concept for the conductor and intermediate insulations by use of windable aluminum nitride (AIN) or aluminum oxide-based low-plastic heat-conducting insulating films to reduce the thermal resistance between the film turns and layers by a factor of 3-10 To significantly reduce the weight and volume of the windings, so that the magnetic circuits of the transformers - in particular width and / or height of the winding - can be significantly reduced.

In a multi-leg transformer of the type according to the invention, the primary and secondary windings are preferably separated from each other by intermediate insulation and a hermetic encapsulation, the cores being thermally and electrically insulated in respective spool penetrations in the coil encapsulation.

The Spulenumguß is preferably a primary and secondary winding hermetically sealed and separated from each other potting compound. This forms together with the windings a compact block for receiving the cores. The potting compound is preferably in turn composed of a resin, preferably epoxy resin with thermally conductive fillers, preferably aluminum nitrite and / or silanized quartz powder and / or isolated metal particles, as far as the casting insulation properties are not affected thereby. However, the invention is not limited to encapsulated or encapsulated coils / windings. The thermal bridge intermediate insulation and thermal bridges Windungsisolation can also be used for conventional transformers without

The primary and secondary windings of the transformers and chokes are preferably foil conductors, but may also be designed as a high-frequency strand and / or profile waveguide (for direct / indirect liquid cooling).

Brief description of the drawings

• FIG. 1 schematically shows the winding of a single-leg or a 2 E, or a 4U transformer in side view, before the encapsulation.
• FIG. 1a shows a winding like Fig. 1 however, for a so-called Topfverguss.
• FIG. 2 schematically shows a cross section of the transformer according to FIG. 1 ; in front view.
• FIG. 2a shows analogously to Fig. 1a ) a winding in an aluminum housing for Topfverguss in cross section.
• FIG. 3 schematically shows a modified embodiment of the transformer according to FIG. 1 ,
• FIG. 4 schematically shows a cross section of the modified transformer according to FIG. 3 ,
• FIG. 5 shows a plan view, and a cross section through a ceramic thermal bridge.
• FIG. 6 shows a plan view and a cross section through an overlapping thermal bridge z. B. as a spray, casting, or sintered compact.
• FIG. 7 shows a plan view and a cross section through a thermal bridge of ceramic for outdoor use for heat dissipation.
• FIG. 8 shows a front view of a medium-frequency transformer with thermal bridges in the encapsulation and other heat-dissipating measures.
• FIG. 9 shows a side view of the transformer according to Fig. 8 with cooling elements.
• FIG. 10 shows a perspective view of the transformer according to FIG. 8 from underneath.
• FIG. 11 shows a perspective view of the transformer according to FIG. 8 from above.
• FIG. 12 shows a plan view of the transformer according to FIG. 8 ,
• FIG. 13 shows a geometry of a Wärmeleitbleches of thermal bridges.
• FIG. 14 shows another embodiment of a medium-frequency transformer in front view.
• FIG. 15 shows the MF transformer of FIG. 14 in side view.
• FIG. 16 shows a cross section through the MF transformer of FIG. 14 ,
• FIG. 17 shows a plan view of the MF transformer of FIG. 14 ,
• FIG. 18 shows a cross section of another embodiment of an MF transformer.
• FIG. 19 shows a plan view of the MF transformer of FIG. 18 with removed cores.
• FIG. 20 shows a representation of the cores of the transformer of FIG. 18 in front and side view.
• FIG. 21 shows a representation of the yokes of the transformer of FIG. 18 in frontal and side view.
• FIG. 22 shows a view of an embodiment of an MF transformer with partly metallic, electrically separated outer surfaces.
• FIG. 23 shows a side view of the transformer of FIG. 22 with metallic outer surfaces and with threaded or rivet holes for mounting radiators or multi-stage chimney or forced air or water radiator heat sinks.
• FIG. 24 shows a section through the transformer according to FIG. 22 with internal cooling surfaces between the two-arm windings.
• FIG. 25 shows a plan view of the transformer of FIG. 22 with removed cores.
• FIG. 26 shows a detail section of an external thermal bridge with thermal bridge contact and cooling plate.
• FIG. 27 shows a transformer according to FIG. 22 with several cooling elements.
• FIG. 28 shows a side view of the transformer of FIG. 27 ,
• FIG. 29 shows a section through the transformer according to FIG. 27 ,
• FIG. 30 shows a plan view of the transformer according to FIG. 27 ,
• FIG. 31 shows a section through a winding of the transformer.
• FIG. 32 shows a view of the layer structure of the winding of the transformer.
• FIG. 33 shows the construction of a thermal bridge-insulated winding of an MF transformer.
• FIG. 34 shows a section through an MF transformer with thermal bridges using the example of a pot transformer.
• FIG. 35 shows a longitudinal section through the transformer according to FIG. 34 ,
• FIG. 36 shows a cross section through the transformer according to FIGS. 34 and 35 with heatpipes.
• FIG. 37 shows a longitudinal section through the transformer according to FIG. 36 ,
• Figure 38 shows a thermal bridge for connection to a heat pipe.
• FIG. 39 shows several thermal bridges for connection to a heat pipe.
• FIG. 40 shows a cross section through a transformer with thermal bridges and heat pipes and external cooling elements. This embodiment is analogously applicable for two-arm transformers, thigh and disk chokes.
• FIG. 41 shows a so-called disk choke in the X-section, in which the windings with thermal bridge insulation according to the above and the insulation to the housing are also designed as thermal bridge insulation.
• Figure 42 shows a disk throttle in axial section with the cylindrical insulation to the core and outer sheath.
• FIG. 43 fictitiously shows a layering foil conductor winding insulation z. B. with layer thicknesses of 0.08 - 0.15 mm and thermal conductivity z. B: 0.4-0.6 W / m K.
• FIG. 44 shows fictitious stratification of foil conductor winding insulation with layer thicknesses of 0.08 - 0.15 mm but with greatly increased "thermal bridge conductivity" greater than or equal to 1.0 W / m K, but usually between 1 - 10 W / m K, made of silicone foil-based Wärmeleitfolien with ceramic or quartz flour fillers.
• FIG. 45 shows exemplary conductor foils, the surface of which is covered with very thin ceramic sintered coatings, where due to the adhesion and the Isolation the ceramic fine grain mixtures are embedded in sintered thin plastic layers. This isolation has over the examples of the FIGS. 43 and 44 only approx. 50% insulation thickness, ie approx. 0.05 mm highly heat-conductive insulation, which further improves the degree of filling of the winding and the heat dissipation.
• FIG. 46 shows analogously to Fig. 45 Conductor insulation, for example, with insulating varnish, the insulating varnish can also be enriched with Wärmeleitpulver. To secure the coated edges, for example, thin polyamide adhesive strips can be wound between the coated film conductors in order to ensure reliable long-term insulation in the edge region of the film conductors without the layers of the winding becoming noticeably thicker radially.

Of course, the above also applies to the impregnation of windings. The impregnating resins / silicones 84 can also be provided with heat-conducting additives according to the invention so that the impregnation can penetrate into the many fine gaps in order to bridge the not insignificant gap heat resistances.

But it can also be an impregnation 85 carried out during winding, so as to ensure that despite optimized Wärmeleit grain mixtures all the gaps of the winding between the conductor foils, the winding insulation and the intermediate insulation are filled.

Description of preferred embodiments of the invention

The Figures 1 and 2 show a molded MF transformer with a winding 50 which is surrounded by an encapsulation 51. Between the layers of the winding 50 flexible thermal bridges 52 are provided, which consist for example of flexible Wärmeleitfolien of windable aluminum nitride or aluminum oxide. Further, preferably ceramic thermal bridges 53 are provided in the interior of the winding, as well as ceramic thermal bridges 54 as Outdoor cooler or as a connection to outdoor coolers. These designs of the thermal bridges are rigid and must therefore be adapted constructively to the winding shapes. But they have in comparison to the flexible thermal bridges significantly higher thermal conductivity.

The FIG. 1 a and 2a show (compared to the FIGS. 1, 2 . 3, 4 ) a so-called pot transformer. The outer and inner contours of the winding are with Wärmeleitkachel 54; 53 or provided with flexible thermal bridges 66 which are coupled to the pot housing gap-free to low-gap and cast together with the cores 69. The Figures 1 - 4 provide windings for transformers in encapsulation and non-encapsulation technology ie applications without pot housing.

For many applications, especially at low power, the winding of the winding and the cores in pot housings takes place in accordance with the FIGS. 1a and 2 B ,
In principle, the winding, equipped with thermal bridges as in 1 and 2. However, winding and cores are thermally (thermally conductive) contacted with the thermal bridges 54 and or 51 on the pot housing 66. Within the coil penetration of the heat transfer is done via thermal bridge 53, 54 and heat-transfer components pos. 67-69.

The same thing happens with the nuclei. The heat losses of the cores / yokes are dissipated via heat conducting lugs or special molded parts to the housing, which can be equipped with and without cooling ribs 70.

The FIGS. 3 and 4 show one opposite the Figures 1 and 2 modified embodiment of a transformer, wherein between each winding layer 50 flexible thermal bridges 52, which also serve as insulation, as well as ceramic thermal bridges 53 are provided which effectively direct the heat generated in winding 50 heat loss to the outside.

The FIGS. 5, 6 and 7 show various possibilities of building solid thermal bridges, such as ceramic thermal bridges 53 and 54, according to the FIGS. 5 and 7 , These thermal bridges 53 and 54 are adapted in their shape - as mentioned - to the respective application.

The thermal bridge according to FIG. 5 For example, is placed between the layers of a winding, while the thermal bridge according to FIG. 7 can represent a thermal bridge for external cooling.

FIG. 6 shows a thermal bridge 61 consisting of an injection molding, casting, or sintered material, which is very cheap and easy to manufacture. The injection-molding material preferably contains additives of very good heat-conductive materials.

The FIGS. 8 to 13 show MF transformers with thermal bridges, in particular internal thermal bridges 58 between the winding layers and outer thermal bridges 57, which are connected to further heat bridges 59 and radiator lugs 55 for dissipating the heat to the atmosphere.
The radiator vanes are realized, for example, by a heat conducting plate 56, as in FIG. 13 is shown. The entire winding region of the transformer is surrounded for example by an epoxy encapsulation 60, which may also consist of good thermal conductivity material but need not.

The FIGS. 14 to 17 show another embodiment of a transformer according to the invention in different views. The MF transformer has a Spulenumguß 1 with a substantially chamfered-rectangular cross section. In the Spulenumguß 1 a primary winding 2a and a secondary winding 2b are cast. This results in a windings 2a, 2b hermetically enclosing block. The front and the back form an end face 3, the z. B. for positioning the terminals 13, 14 of the MF transformer can be used. At the bottom End transformer feet 4 are preferably provided, which have a sprue fitting 6 for floor or wall mounts.

Between the winding layers 2a and 2b, a flexible intermediate insulation 7 is provided, which also serves as a thermal bridge between the winding layers, so that the loss heat generated in the windings is immediately transported in the direction of the cores or to the outside.

In the coil encapsulation 1, for example, two three-layer windings 2a and 2b are inserted, wherein the windings are juxtaposed by a Isolierzwischenguß 19 separated from each other. Alternatively, 20 cavities 20 can be provided on the front and back 3 of the Spulenumgußes, which provide better dissipation of heat from the coils 2a, 2b to the outside in the environment. The electrical connection of the windings 2a and 2b takes place in integrated boarding rooms 11 and 12, which are also fully filled with potting compound.

Each coil has a coil penetration, wherein the coil penetrations are arranged plane-parallel to each other. The coil penetrations have, for example, a rectangular cross-section, with bevelled areas on the narrow sides of the penetration, wherein in each case ribs 9 arranged parallel to one another are provided on one longitudinal side of the rectangle. The ribs 9 to the surfaces of the coil penetration are arranged plane-parallel. Further, the ribs 9 are preferably longitudinally conically shaped, both laterally and in their breakthrough width.

The nuclei 21, 22 and yokes 18, as in FIGS. 20 and 21 are indicated, are joined from I-cores or cut cores to assemblies. The cores 21, 22 or yokes 18 are then externally and in the region of the adhesive joints to the ribs 9 of the Spulenumgußes 1 with a thermal insulating layer 5, preferably glued GfK. This ensures that the cores 21, 22 of the Windings 2a, 2b can be thermally decoupled. These pasted with the insulating layer 5 cores 21, 22 are now fixed on one side by gluing to the ribs 9. The cores 21, 22 thus have contact only with the coil encapsulation 1 in the region of the ribs 9. Thus, according to the invention, no mechanical supporting or clamping elements are required for the cores 21, 22 and yokes 18, since the cores lie directly on the ribs 9 within the coil penetrations be applied.

As stated, a wide variation of the transmission power is possible by varying the height and / or width and adaptation to different core cross sections and distances with the proposed two- or multi-leg design. The cores 21, 22 are freely suspended in the windings on all sides and attached to the ribs 9 on only one side. As a result, the cores 21, 22 held in the Spulenumguß 1 due to the bond "elastic-solid" and very quiet. All parts for fixing the cores 21, 22 are made of non-conductive materials, so that the cores can float freely in terms of potential. The cores are not grounded in contrast to conventional transformers. Preference is given to using ferrite cores or nanocrystalline or amorphous cores.

The FIGS. 18 and 19 show a slightly modified embodiment of an MF transformer according to the invention, in which case somewhat narrower ribs 9 are used for fastening the cores 21, 22. Depending on the configuration of the coil openings and the ribs, the transformer can be optimized either in terms of its leakage inductance or its noise emission. Again, intermediate thermal bridging insulations 7 are used between the layers of windings 2a and 2b.

The FIGS. 22 to 26 show a transformer with thermal bridges and base surfaces for internal and external cooling. The transformer comprises both outer cooling plates 25 and inner cooling plates 26, which have corresponding ones Thermal bridge contacts 27 are thermally conductively connected to the windings 2a and 2b, respectively. The windings are, as described above, separated from each other by intermediate thermal insulation 7. The cooling plates 25 and 26 are fixed for example by means of an undercut 28 in the casting resin of the transformer. The cooling plates 25 and 26 may have corresponding screw thread 29 to which then additional cooling elements can be screwed.

The FIGS. 27 to 30 show the transformer according to the FIGS. 22 to 26 with external cooling elements 30 and 31 which are mounted on the cooling plates 25 and 26, preferably screwed on, are. The cooling element 31 has, for example, a number of cooling webs 32, between which cooling chimneys 33 form, which ensure good heat dissipation by air circulation. In other words, the coolers have the task of compensating for either the reduction in area of the transformers associated with the volume reduction or the increased power loss that occurs with the possible power increase.

The FIGS. 31 and 32 show by way of example a cross section and a plan view of one of the two windings 2a and 2b, for example, the transformers according to the Figures 14 or 22. The conductors are preferably copper foil conductors 23, which are wound with the interposition of an intermediate insulation 24 is substantially square or rectangular. The Cu conductors 23 are externally connected in the terminals 13, 14 of the Spulenumgußes 1.
The windings are firmly and hermetically sealed with a potting compound of a resin, preferably epoxy resin, with thermally conductive fillers, but it need not be in conventional transformers.

The windings can also be wrapped with a coarse-meshed glass silk tape, so that the Wicklungsumguß is highly stable, heat and cold shock resistant. The conventional mica insulation is replaced according to the invention by thermal bridges 34 and cast-resin intermediate insulating 7.

The magnetic cores are provided with thin GfK plates for stress compensation and as adhesion promoter. Furthermore, side recesses 16 remain for the air bubble rise to the middle or outside for the process improvement during the casting process of the windings.

FIG. 33 shows starting from the example of FIGS. 31 and 32 the production of a winding with thermal bridges, wherein the individual parts of the windings are connected by thermal bridges 34 and 34 a heat-conducting together.

The FIGS. 34 and 35 show a further embodiment of a transformer with thermal bridges in the form of a pot transformer. Between the windings 35 are thermal bridge insulation, for example made of aluminum nitride, and cast intermediate insulations 38. There are both internal thermal bridges 36 and outer thermal bridges 44 are provided, the internal thermal bridges 36, the heat between the winding bearings 35 derived and to the outer Give thermal bridges 44, which then deliver it to inner-outer heat conductor 39, which are connected to a corresponding cooling element 41. The cooling element 41 is preferably integrated in the pot housing 40 of the transformer.

The FIGS. 36 and 37 show a similar embodiment as the FIGS. 34 and 35 , wherein in addition to the inner thermal bridges 36 connected heat pipes 43 are provided, which absorb the heat generated in the interior of the winding 35 and deliver to the outside to the cooling elements 41.

The Figures 38 and 39 show possibilities of heat dissipation and heat dissipation from the interior of the transformer to the heat pipe 43. _® Windungs- and intermediate insulation 47 made of insulating Wärmeleitmaterial be used to transfer the heat to a Wärmeleitfahne the heat pipe. The heat is passed through a ceramic strip 48 to the heat pipe 43 and with a metal rail part, such as copper 49, evenly transferred to the heat pipe 43.

FIG. 40 Finally, shows an example of a transformer with thermal bridges and leading heat pipe to an external cooling element 45. The heat generated in the interior of the transformer is passed through the heat pipes 43 to the external cooling element 45, which is cooled by a cooling air flow 46. The external cooling element may, for example, be located in a separate room which is separated from the space of the transformer by a bulkhead wall.

The FIGS. 41 and 42 show an example of a disc choke for railway or industrial applications. The schematic diagrams show how, in the sense of the invention, basically the windings of transformers and reactors are traversed. The windings 80 of the choke coil, for example, consist of a foil conductor, high-frequency strand or a waveguide. The windings 80 are electrically insulated from each other by thermal bridge insulation 76. Between the outer diameter of the winding and the throttle jacket thermal bridges 75 are provided, as well as thermal bridges 76 between the core and the inner diameter of the coil. The potting 82 of the disc choke is preferably made of thermally conductive resins, with a specific thermal conductivity of, for example, greater than 1.6 W / m K. The core 78 and the disc (yoke) 79 consist for example of powder composite materials or other soft magnetic materials.

As in connection with the FIGS. 43 to 46 is shown, further thermally conductive winding insulation 81 may also be provided. For example, Harteloxal 81 a for Alufolieleitern, Dünnstfolien 81 b, vortex sintering ceramic powder plus bonding materials, paint insulation 81 c with heat conducting powder or very thin ISo-Strips 86 (increased protection in the edge region). The electrical connections 83 of the throttle are designed as a passage through the disk housing.

Furthermore, when impregnating between conductor and winding insulation, as well as conductors and intermediate insulation (also heat conducting foils), an impregnating varnish 84 or impregnating varnish application 85 can be used which has been enriched with heat-conducting powder of different grain size.

Pos. 75 in FIG. 43 symbolizes a conventional isolation of the windings 80. The pos 81 a, 81 b and 81 c in the FIGS. 44, 45 and 46 It should be noted that the winding insulation with the relatively small voltage differences between adjacent windings allow foils with high and special addition of heat conduction materials with up to a specific thermal conductivity of currently 8- 10 W / m K.

Earth and intermediate insulation, because of the higher voltage values, requires heat conducting foils that also require high dielectric strengths. This is usually at the expense of the degree of filling and the thermal conductivity of the Wärmeleifolien. Ie. The usable foils for earth and intermediate insulation usually only have about 50% of the values for the thermal conductivity as the heat conducting foils for winding insulation, but this still represents a factor of 3-10 higher thermal conductivity compared to previous insulation materials.

Moreover, it is possible, the cover layers of an intermediate insulation of previous insulating z. B. mica polyamide, etc. to wrap and to wrap the main strength of the intermediate insulation of thermal bridging films, which increases the overall thermal resistance but only slightly because of the proportional layer thickness ratios, however, has the advantage of decades in Trafobau proven materials to place directly where the voltage stress on the Intermediate insulation is highest.

Similar combinations are also possible with the winding insulation. The inner winding insulation (the inner layers) can be made with "thermal bridge insulation" 81, while z. B. "outer Windungsisolationen" often can be made from conventional Windungsisolationen.

Windings with impregnations, which have better heat-conducting properties than previous impregnations, are optimally completed.

The impregnations 84, 85 can, similar to the thermal bridging films, be enriched with Wärmeleitpulvern, which means a better overall heat engineering design of MF transformers and chokes.

What appears to be suitable with regard to the optimum overall economic and technical design and the reduction of the volumes, weights and electrical losses can be calculated, designed and manufactured more reliably with the instruments according to the invention and more easily for the optimum design. In almost all cases, the next higher operational or functional level benefits. Power converters, converters, and industrial capital goods are becoming lighter, more compact, more functional, and in many cases safer and less expensive.

LIST OF REFERENCE NUMBERS

1

Coils and coils for transformers

2a

Molded winding pot transformers etc.

2 B

Molded winding pot transformers etc.

3

Face (for connections)

4

Trafofuß

5

Insulation plate (on core)

6th

Pouring fitting (transformer foot)

7

Intermediate insulation (coils)

8th.

I-cores parallel bonding

9th

ribs

10

Gap (chimney ventilation)

11

Boarding space (primary winding)

12

Boarding room (secondary winding)

13

Connection (secondary)

14

Connection (primary)

15

Cast connection (coils)

16

Side recess (cores)

17

Insulation plate (yoke)

18

yoke

19

Coil insulation

20

air duct

21

core

22

core

23

Cu winding

24

Intermediate insulation (coils)

24a

potting compound

25

Cooling plate (outside)

26

Cooling plate (inside)

27

Wärmebrückenkontaktierung

28

undercut

29

screw thread

30

cooling element

31

cooling element

32

cooler fins

33

cooling chimney

34

thermal bridge

35

winding

36

Thermal bridges (inside)

37

Isolierwärmebrücken

38

between isolation

39

Indoor / outdoor heat conductor

40

pot housing

41

cooler

42

Connections (electr.)

43

Heatpipe

44

Outdoor heat bridges

45

Cooler (external)

46

Cooling air flow

47

Wärmeleitfahne

48

ceramic bar

49

metal bar

50

winding

51

recast

52

Thermal bridge (flexible)

53

Thermal bridge (ceramic)

54

Thermal bridge (ceramic)

55

cooler flags

56

heat conducting

57

Thermal bridge (outside)

58

Thermal bridge (inside)

59

Thermal bridge (primary)

60

Epoxy resin encapsulation

61

Thermal bridge (injection molding)

65

Heat flow contacting winding P54 tile to pot housing

66

Heat flux contacting Winding flex. Thermal bridge P57 T.Housing

67

Alu or CU metal block for heat dissipation core pot housing

68

Heat flow via tile 53 via AL / CU drainage lug to pot housing

69

Heat flow from core to pot housing

70

Cooling ribs on pot housing

71

MF transformer resin casting in the pot housing

75

Thermal bridge between outside diameter Winding to choke jacket

76

Thermal bridge insulation between the turns of the choke coil

77

Thermal bridge between core and the inner diameter coil

78

Core: Powder composite material (or other soft magnetic materials.

79

Slice z. B: Powder composite (analogously, yokes, ditto 78

80

Foil conductor or high-frequency strand or waveguide etc.

81

further heat-conducting winding insulation 81a) hard anodised aluminum foil conductors, 81 b) thinnest foils, vortex sintering ceramic powder plus bonding materials, 81 c) lacquer insulations with heat-conductive powder and very thin insulating foil shims 86 (increased protection in the edge area)

82

Pouring of the disk throttle z.B: with wärmeleitf. Resins. ≥1.6 W / m K

83

Electrical connections Throttle equal to execution

84

Impregnating varnish enriched with heat conducting powder different grain size

85

Impregnating lacquer application during winding between conductor and winding insulation, as well as conductor and intermediate insulation (also heat conducting foils)

86

Insulation strips supplement

Claims (21)

1. Inductive component with at least one winding (2a, 2b), wherein one or more heat bridging intermediate insulations (7) are arranged between individual layers of the winding and/or a further winding, characterised in that the heat bridging intermediate insulations comprise flexible insulation foils (52), in which heat-conducting ceramic or quartz powder-containing fillers are incorporated, and in that the inductive component is a transformer, in particular a medium frequency transformer, with at least one primary and secondary winding (2a, 2b), which are magnetically coupled, and have at least one core for the primary and secondary windings, which is held in a corresponding coil feed-through in the coil encapsulation, one or more heat bridging intermediate insulations being arranged between the primary and secondary winding, other windings, or metallic inner and outer parts.
2. Inductive component with at least one winding (2a, 2b), wherein one or more heat bridging intermediate insulations (7) are arranged between individual layers of the winding and/or a further winding, characterised in that the heat bridging intermediate insulations comprise flexible insulation foils, in which heat-conducting ceramic or quartz powder-containing fillers are incorporated and in that the inductive component is a throttle with or without a core.
3. Inductive component according to any one of the preceding claims, characterised in that the heat bridging intermediate insulations (7) substantially consist of flexible silicone heat conducting foils.
4. Inductive component according to any one of the preceding claims, characterised in that the heat bridging intermediate insulations (7) have a specific heat conductivity of greater than or equal to 1.3 W/mK.
5. Inductive component according to any one of the preceding claims, characterised in that in the heat bridging intermediate insulation (7), first and outer layers of the insulation consist of mica, polyester or polyamide/kapton foils.
6. Inductive component according to any one of the preceding claims, characterised in that the insulation of the primary and secondary windings consists of heat conducting foils (81) with the same or a higher specific heat conductivity than that of the heat bridging intermediate insulations, the thickness of these heat conducting foils generally being less than that of the heat bridging intermediate insulations.
7. Inductive component according to any one of the preceding claims, characterised in that the insulation of the primary and secondary windings (81 a, 81 b, 81c) also consists of heat conducting insulating material anodised, sintered, layered and partially interposed on foils or other conductors.
8. Inductive component according to any one of the preceding claims, characterised in that combined winding insulations with inner layers generally with higher heat conductivity and outer layers with lower heat conductivity are provided.
9. Inductive component according to any one of the preceding claims, characterised in that the insulation (76) of the primary and secondary windings consists of polyester, polyamide, insulating paper or mica, mixed insulations.
10. Inductive component according to any one of the preceding claims, characterised in that the heat bridging intermediate insulation (53, 54) partly or completely comprises ceramic tiles or ceramic overlapping profiles which are distributed on the peripheries of the intermediate insulations of the inductive component and/or in conjunction with flexible (52) or cast intermediate insulations.
11. Inductive component according to any one of the preceding claims, characterised in that an additional heat bridging insulation (57) is provided on the outer face of the primary and/or secondary winding.
12. Inductive component according to any one of the preceding claims, characterised in that an additional heat bridging insulation (58) is provided on the inner face of the primary and/or secondary winding.
13. Inductive component according to any one of the preceding claims, characterised in that the heat bridging insulation has metal faces (25, 26) joined or cast on the outer face of the primary and/or secondary winding, on which metal faces cooling elements (30, 31) with high heat conductivity can be fastened.
14. Inductive component according to any one of the preceding claims, characterised in that the heat bridges (53, 54, 57 to 59) and heat bridging intermediate insulations (7) contain aluminium nitrite (AIN) or aluminium oxide.
15. Inductive component according to any one of the preceding claims, characterised in that earth and layer insulations between the winding, cores, yokes, discs and outer casings are formed like the so-called intermediate insulations of MF transformers.
16. Inductive component according to any one of the preceding claims, characterised in that the winding insulations are formed like the winding insulations of MF transformers.
17. Inductive component according to any one of the preceding claims, characterised in that the impregnation of the windings is provided with heat-conducting additives.
18. Inductive component according to any one of the preceding claims, characterised in that the encapsulation of the windings is provided with heat-conducting additives.
19. Inductive component according to any one of the preceding claims, characterised in that the heat bridging intermediate insulation (7) and/or the heat bridging insulation (53, 54, 57 to 59, 75 to 83) is connected in a heat conducting manner to at least one heat pipe (43).
20. Inductive component according to claim 19, characterised in that the heat pipe (43) is arranged in such a way that the heat of the conductive component is guided away to an external cooling element (45) spaced apart from the inductive component.
21. Inductive component according to any one of the preceding claims, characterised in that the heat bridging insulations (53, 54, 57 to 59, 75 to 83) consisting of a first layer, multiply wound heat conducting foil and an outer layer have a specific heat conductivity of greater than or equal to 1.3 W/mK.

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