Manufacturing method for transformer with low surface thermal radiation

Abstract

The present invention belongs to the technical field of transformers. Provided is a manufacturing method for a transformer with low surface thermal radiation. In the transformer produced by means of the manufacturing method in the present invention, a winding and a water-cooled heat dissipation assembly are integrally poured into a whole by means of a thermally conductive filler by using a pouring mold, which can not only guarantee the heat dissipation of each winding structure, but can also reduce the overall vibration and noise of the transformer; and an inner mold core arranged on the pouring mold facilitates the effective installation of a subsequent iron core and does not affect the installation of water-cooling lines and circuits. Specifically, the heat directly dissipated by the transformer into a surrounding space can be reduced to less than 1 / 10 of the original amount, and the temperature difference inside the winding can be reduced by about 10-20 degrees compared with the method of placing a water-cooling plate on a side surface, which can reduce a surface thermal radiation temperature of the transformer by 50-80 degrees, and a thermal-conductivity coefficient of a thermally-conductive castable is improved by about 16 times compared with a thermal-conductivity coefficient of a pure epoxy resin.

Description

A method for manufacturing a low surface thermal radiation transformer

[0001] Related applications

[0002] This application claims priority to Chinese invention patent application No. 202311538210.1 filed on November 17, 2023, entitled “A method for manufacturing a low surface thermal radiation transformer”. Technical Field

[0003] The present invention relates to the technical field of transformers, and in particular to a method for manufacturing a transformer with low surface heat radiation. Background Art

[0004] A transformer is a device that uses the principle of electromagnetic induction to change AC voltage. It is an indispensable and important equipment in the power system. During the operation of the transformer, due to the changes in the magnetic field inside the transformer, the transformer body will vibrate and generate heat.

[0005] Transformers have a wide range of uses. In certain areas with special high-performance requirements such as quietness, low vibration and low thermal radiation, transformer products have very high requirements for vibration and heat dissipation performance. Conventional transformers cannot meet these requirements. Therefore, how to reduce transformer vibration (noise) and heat radiation has become an issue that cannot be ignored. Using different measures to achieve low vibration (noise) and heat radiation of transformers is a major topic in transformer research. Referring to Figures 1 and 2, a low surface heat radiation transformer designed by the applicant is shown. The transformer is formed by wrapping a water-cooled heat dissipation component in the winding and casting the winding and the water-cooled heat dissipation component into an integral cast body using a castable material, so that the surface heat radiation of the transformer and the vibration and noise of the entire transformer meet the requirements.

[0006] Although the above-mentioned transformer structure is cleverly designed to reduce vibration, noise and surface heat radiation, the applicant discovered during the research and development and manufacturing process that it involves not only the wrapping of water-cooled heat dissipation components and the connection of pipes, but also the need to cast the windings and water-cooled heat dissipation components as a whole, while also ensuring effective installation between the various components. If conventional transformer manufacturing methods are used, this may lead to problems such as the windings and water-cooled heat dissipation components being unable to be cast as a whole, or the iron core and iron yoke being unable to be effectively installed after the windings and water-cooled heat dissipation components are cast as a whole. Therefore, a new manufacturing process is required for the above-mentioned transformer.

[0007] Summary of the Invention

[0008] The object of the present invention is to provide a novel manufacturing method of a low surface heat radiation transformer.

[0009] The technical solution of the present invention is as follows: A method for manufacturing a low surface thermal radiation transformer, comprising:

[0010] S1. During the winding process of the winding, at least part of the components in the water-cooled heat dissipation component are wrapped inside the winding, leaving the connecting pipelines of the water-cooled heat dissipation component and making the connecting pipelines extend outside the winding;

[0011] S2. Prepare the heat-conducting casting material and the casting mold that matches the overall structure of the winding and the water-cooled heat dissipation component;

[0012] S3. Install multiple windings and the corresponding water-cooled heat dissipation components into the casting mold at a predetermined interval, and each winding is sleeved on an iron core column mold in the casting mold;

[0013] S4. Assemble the water-cooled heat dissipation component completely, and connect the connecting pipelines extending from each winding to each other or to the water-cooled input and output pipelines;

[0014] S5. Inject the heat-conducting casting material into the casting mold and cure it integrally;

[0015] S6. Take out the integrally cast winding and the water-cooled heat dissipation component from the casting mold, and insert an iron core column that matches the specification of the iron core column mold into each winding 3.

[0016] Furthermore, the winding method in the above step S1 includes the winding of the inner winding and the outer winding. The winding of the inner winding is carried out on the winding mold. After the inner winding is wound, a main insulation is set outside the inner winding, and the outer winding is wound outside the main insulation. During the winding process of the inner winding and the outer winding, the water-cooled heat dissipation component is wrapped and installed between multiple turns of the inner winding and / or the outer winding, and / or the water-cooled heat dissipation component is wrapped and installed in the interval between the inner winding and the outer winding.

[0017] Furthermore, the water-cooled heat dissipation component includes a special-shaped water-cooled plate and a water-cooled pipe. At least two of the special-shaped water-cooled plates are assembled to surround the inner winding or the outer winding part inside them, and the water-cooled pipe is arranged in an S-shaped reciprocating manner along the length or width direction of the special-shaped water-cooled plate inside the special-shaped water-cooled plate.

[0018] Furthermore, the two water-cooled pipe ends of the water-cooled pipe extend out of the top or bottom end of the special-shaped water-cooled plate. The water-cooled pipe ends between adjacent water-cooled pipes are connected to each other through a connecting pipe, and the water-cooled pipe ends and the connecting pipe are detachably connected by threaded connection or flange connection or clamp connection.

[0019] Furthermore, the two water-cooled pipe ends of the water-cooled pipe extend out of the top or bottom end of the special-shaped water-cooled plate from the short side directions on both sides of the winding.

[0020] Furthermore, the special-shaped water-cooled plate is in a "C" shape, and two "C"-shaped special-shaped water-cooled plates can be assembled into a complete ring to surround the inner winding or the outer winding part inside them.

[0021] Furthermore, in the above step S2, the thermally conductive castable includes components A and B, wherein component A is epoxy resin plus filler, and component B is an anhydride curing agent plus filler, and the filler is a ceramic filling material of alumina (Al2O3) and aluminum nitride (AlN); wherein component A includes epoxy resin, modified alumina, and aluminum nitride, and component B includes an anhydride curing agent, modified alumina, and aluminum nitride, wherein the amount of aluminum nitride is greater than the amount of modified alumina, and preferably,

[0022] The preparation method of the thermal conductive castable comprises:

[0023] ① Surface modification of aluminum oxide (Al2O3): Add vacuum-dried Al2O3 powder, silane coupling agent containing 4-6wt% of Al2O3 powder, and anhydrous ethanol in an amount 10 times that of the silane coupling agent to a vacuum reactor, maintain the temperature at 50-70°C, stir and ultrasonicate for at least 30 minutes, wash once with anhydrous ethanol, and then ultrasonicate for at least 10 minutes. Remove and wash once with ethanol, filter and then wash twice or more with anhydrous ethanol, let stand for at least 30 minutes, place in a vacuum oven, dry at 70-90°C for at least 24 hours, remove and grind the block into powder, and then place in a container for later use;

[0024] ② Preparation of component A:

[0025] Recipe ratio:

[0026] First, the modified alumina (Al2O3) and aluminum nitride (AlN) are placed in a vacuum oven respectively. After drying, the mixture is preheated to 70-90 degrees, placed in a reactor, stirred and degassed, and gradually vacuumed to 300-400Pa. This process is maintained for a predetermined time to ensure that the mixture is stirred evenly and degassed. The mixture is then placed in a container of material A for later use.

[0027] ③ Preparation of component B:

[0028] Recipe ratio:

[0029] Similarly, the modified alumina (Al2O3) and aluminum nitride (AlN) are placed in a vacuum oven respectively. After drying, the above-proportioned mixture is preheated to 70-90 degrees, put into the reactor, stirred and degassed, and gradually vacuumed to 300-400Pa. This process is maintained for a predetermined time (for example, 30-60 minutes) to ensure that the mixture is evenly stirred and degassed, and then placed in the B material container for standby use.

[0030] Preferably, the particle size of aluminum oxide (Al2O3) and aluminum nitride (AlN) in the above-mentioned components A and B is controlled to be 100-200 mesh.

[0031] Furthermore, the casting mold described in the above steps S2 and S3 includes a base plate, an outer mold, an inner mold core and a pressure plate. The outer mold is fixedly mounted on the top surface of the base plate to form a closed casting area on the inner side of the outer mold. The inner mold cores with the same number of windings are vertically fixed on the inner side of the outer mold at a distance. The wound windings are respectively mounted on the outside of an inner mold core, and the water-cooling heat dissipation components between the windings are connected; the pressure plate is fixedly covered on the top surface of the outer mold, and a channel for casting to the casting area is reserved on the pressure plate.

[0032] Furthermore, the pouring method of the thermal conductive castable in step S5 is:

[0033] The first step is to place the entire casting mold in a drying and curing oven, maintain drying and curing at 90-110 degrees for 2-4 hours, then maintain drying and curing at 70-85 degrees for 4-6 hours, and finally maintain it at this temperature for standby use;

[0034] The second step is to place the dried and solidified casting mold as a whole in the casting equipment, heat it to 70-85 degrees and then evacuate it;

[0035] The third step is to put the prepared A and B components into the mixing tank of the pouring equipment in a ratio of 10:9, heat it to 60-70 degrees, and vacuum and stir to degas until the bubbles are completely separated and the pouring requirements are met;

[0036] The fourth step is to add materials; maintain the vacuum degree, open the discharge valve, and allow the mixture to flow into the casting mold. The casting process is controlled within 1 hour.

[0037] Furthermore, in the above step S5, the winding, water-cooled heat dissipation component cast into one piece are transferred together with the casting mold to a curing furnace for curing. The specific curing process is as follows: maintain 70-85 degrees for 3-7 hours, heat to 90-110 degrees for 3-7 hours, then heat to 130-150 degrees for 10-18 hours, and naturally cool to 90-110 degrees.

[0038] Furthermore, the above step S6 also includes wrapping the outer portion of the integral casting body formed by casting the winding and the water-cooling heat dissipation component with a heat insulation layer, and fixing and installing iron yokes on the top and bottom of the plurality of core columns.

[0039] The present invention also provides a thermal conductive castable and a preparation method thereof, wherein the thermal conductive castable (5) comprises components A and B, wherein component A comprises epoxy resin plus filler, and component B comprises an acid anhydride curing agent plus filler, wherein the filler is a ceramic filling material such as alumina and aluminum nitride; wherein component A comprises epoxy resin, modified alumina, and aluminum nitride, and component B comprises an acid anhydride curing agent, modified alumina, and aluminum nitride, wherein the amount of aluminum nitride is greater than the amount of modified alumina, and preferably,

[0040] The preparation method of the thermal conductive castable comprises:

[0041] ① Alumina surface modification: Add vacuum-dried alumina powder, 4-6wt% silane coupling agent of alumina powder, and 10 times the amount of anhydrous ethanol used for the silane coupling agent to a vacuum reactor, maintain the temperature at 50-70°C, stir and ultrasonicate for at least 30 minutes, wash once with anhydrous ethanol, and then ultrasonicate for at least 10 minutes. Remove and wash once with ethanol, filter and then wash two or three times with anhydrous ethanol, let stand for at least 30 minutes, place in a vacuum oven, dry at 70-90°C for at least 24 hours, remove and grind the block into powder, and then place in a container for later use;

[0042] ② Preparation of component A:

[0043] Recipe ratio:

[0044] First, the modified alumina and aluminum nitride are placed in a vacuum oven respectively. After drying, the mixture is preheated to 70-90 degrees, put into the reactor, stirred and degassed, and gradually vacuumed. This process is maintained for a predetermined time to ensure that the mixture is stirred evenly and degassed. The mixture is then placed into the material A container for later use.

[0045] ③ Preparation of component B:

[0046] Recipe ratio:

[0047] First, place the modified alumina and aluminum nitride in a vacuum oven respectively. After drying, preheat the mixture in the above proportion to 70-90 degrees, put it into the reactor, stir and degas, and gradually evacuate to 300-400Pa. This process is maintained for a predetermined time to ensure that the mixture is evenly stirred and degassed. Then, put it into the material B container for standby use.

[0048] The present invention also provides a transformer manufactured using the manufacturing method, characterized in that: the transformer includes an iron core column, a winding, a water-cooled heat dissipation component and a thermally conductive castable material, the heat dissipation component is arranged adjacent to at least part of the side surface of each winding, the winding and the heat dissipation component are cast into an integral cast body through the castable material, and the base is fixedly installed on the iron core component and the bottom of the cast body, wherein the thermally conductive castable material includes components A and B, component A is epoxy resin plus filler, and component B is an acid anhydride curing agent plus filler, and the filler uses ceramic filling materials such as alumina and aluminum nitride; wherein component A includes epoxy resin, modified alumina, and aluminum nitride, and component B includes an acid anhydride curing agent, modified alumina, and aluminum nitride, wherein the amount of aluminum nitride is greater than the amount of modified alumina.

[0049] In a transformer produced using the manufacturing method of the present invention, the winding and the water-cooled heat dissipation assembly are integrally cast into a single unit through a casting mold using thermally conductive fillers, thereby ensuring the heat dissipation of each winding structure and reducing the vibration and noise of the entire transformer. The inner mold core provided on the casting mold facilitates the effective installation of the subsequent iron core and does not affect the installation of water-cooling pipes and lines. Specifically, the heat directly dissipated by the transformer to the surrounding space can be reduced to less than 1 / 10 of the original amount, the temperature difference inside the winding can be reduced by approximately 10-20 degrees compared to the method of placing a water-cooling plate on the side, and the heat radiation temperature of the transformer surface can be reduced by 50-80 degrees. At the same time, the thermal conductivity of the thermally conductive castable is increased by approximately 16 times compared to the thermal conductivity of pure epoxy resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] FIG1 is a flow chart of a transformer manufacturing method according to the present invention.

[0051] FIG2 is a schematic diagram of the main plane structure of the transformer in the present invention.

[0052] FIG3 is a schematic diagram of the cross-sectional structure of the transformer and a schematic diagram of a setting position of the water-cooling heat dissipation component 4 in the present invention.

[0053] FIG4 is a schematic diagram of the cross-sectional structure of the winding 3 and another schematic diagram of the arrangement position of the water-cooling heat dissipation component 4 in the present invention.

[0054] FIG5 is a schematic plan view of the structure of the water-cooling heat dissipation component 4 of the present invention.

[0055] FIG6 is a top view of the water-cooling heat dissipation component 4 of the present invention.

[0056] FIG7 is a schematic structural diagram of a casting mold 8 of the present invention.

[0057] FIG8 is a schematic structural diagram of the casting mold 8 after the pressing plate 84 is removed according to the present invention.

[0058] FIG9 is a schematic structural diagram of the intermediate pressure plate 84 of the present invention.

[0059] The accompanying drawings are described as follows: iron core column 1, iron yoke 2, winding 3, inner winding 31, outer winding 32, water-cooled heat dissipation component 4, special-shaped water-cooled plate 41, water-cooled pipe 42, water-cooled pipe end 43, connecting pipe 44, thermal conductive castable 5, thermal insulation layer 6, casting body 7, casting mold 8, base plate 81, outer mold 82, inner mold core 83, pressure plate 84. DETAILED DESCRIPTION

[0060] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings. The following further illustrates the content of the invention in conjunction with the drawings:

[0061] Embodiment 1

[0062] Referring to FIGS. 2-4 of the specification, the low surface heat radiation transformer of this embodiment includes three vertical iron core columns 1, yokes 2 respectively fixedly installed at the top and bottom of the three iron core columns 1, windings 3 and a water-cooled heat dissipation component 4; a set of windings 3 is wound around the outside of each iron core column 1, and each set of windings 3 includes an inner winding 31 and an outer winding 32 wound outside the inner winding 31. The inner winding 31 and the outer winding 32 are wound in a concentric structure, and a certain interval is reserved between the inner winding 31 and the outer winding 32. The water-cooled heat dissipation component 4 is wound in the interval between the inner winding 31 and the outer winding 32, and / or is arranged between multiple turns of the inner winding 31 and / or the outer winding 32; the three windings 3 and the corresponding water-cooled heat dissipation components 4 are installed in a matching casting mold 8 and are cast into an integral casting body 7 through a heat-conducting casting material 5, and a heat-insulating layer 6 is wrapped outside the casting body 7.

[0063] Referring to FIGS. 3-6, the water-cooled heat dissipation component 4 includes a special-shaped water-cooled plate 41 and a water-cooled pipe 42. The special-shaped water-cooled plate 41 is in an "L" shape, and two "L"-shaped special-shaped water-cooled plates 41 can be assembled into a complete ring to surround a part of the inner winding 31 or the outer winding 32 inside; the water-cooled pipe 42 is arranged in an "S" shape in the special-shaped water-cooled plate 41 along the length or width direction S of the special-shaped water-cooled plate 41; the two water-cooled pipe ends 43 of the water-cooled pipe 42 extend out of the top or bottom of the special-shaped water-cooled plate 41 from the short side directions of both sides of the winding 3, and the water-cooled pipe ends 43 between adjacent two water-cooled pipes 42 are connected by a connecting pipe 44, and the water-cooled pipe ends 43 and the connecting pipe 44 are detachably connected by threaded connection or flange connection or clamp connection.

[0064] In one embodiment, referring to FIG. 3, the two special-shaped water-cooled plates 41 are assembled and arranged in the interval between the inner winding 31 and the outer winding 32, and the water-cooled heat dissipation component 4 surrounds the inner winding 31. The dotted lines in FIG. 3 are the center lines of each winding.

[0065] In another embodiment, referring to Figure 4, the water-cooling heat dissipation component 4 can also be arranged between the multi-turn coils of the inner winding 31 and / or the outer winding 32, that is, the water-cooling heat dissipation component 4 is wrapped between the inner winding 31 and / or the outer winding 32. Specifically, the two special-shaped water-cooling plates 41 are assembled to surround the inner side of the inner winding 31 or the outer winding 32; similarly, a water-cooling heat dissipation component 4 can also be provided in the gap between the inner winding 31 and the outer winding 32, or an insulating component can be provided in the gap between the inner winding 3 and the outer winding 32, and the insulating component can be a mesh plate, an airway rod or a composite insulation.

[0066] 7-9 of the specification, the casting mold 8 includes a base plate 81, an outer mold 82, an inner mold core 83 and a pressure plate 84. The outer mold 82 is fixed on the top surface of the base plate 81 to form a closed casting area on the inner side of the outer mold 82. The inner mold core 83 with the same number of windings 3 is fixed vertically on the inner side of the outer mold 82 at a distance. The wound windings 3 are respectively mounted on the outside of an inner mold core 83. The inner mold core 83 matches the specifications of the iron core column 1, and a draft angle is provided along the height direction of the inner mold core 83 for convenient demolding, and the water-cooled heat dissipation components 4 between the windings 3 are connected through a connecting pipe 44; the pressure plate 84 is fixed to cover the top surface of the outer mold 82, and a channel for pouring heat-conducting castable 5 into the casting area is reserved on the pressure plate 84.

[0067] Example 2

[0068] In this embodiment, the manufacturing method of the transformer in embodiment 1 is described. Referring to FIG1 of the specification, the manufacturing method of the low surface heat radiation transformer in this embodiment includes:

[0069] S1, winding the winding 3. During the winding process of the winding 3, the two special-shaped water-cooling plates 41 in the water-cooling heat dissipation component 4 are assembled and installed outside the wound portion. Then, the remaining portion of the winding 3 is wound outside the special-shaped water-cooling plates 41, so that the special-shaped water-cooling plates 41 are tightly embedded in the interior of the winding 3. The water-cooling pipe end 43 of the water-cooling heat dissipation component 4 is reserved and extended to the outside of the winding 3.

[0070] S2, preparing a heat-conducting castable material 5 and a casting mold 8 that matches the overall structure of the winding 3 and the water-cooling heat dissipation component 4;

[0071] S3, the three windings 3 and the corresponding water-cooling heat dissipation components 4 are mounted on three inner mold cores 83 spaced apart in the casting mold 8, with each winding 3 mounted on one inner mold core 83;

[0072] S4, completely assembling the water-cooling heat dissipation assembly 4, connecting the water-cooling pipe ends 43 extending from the windings 3 to each other or connecting the water-cooling pipe ends 43 to the water-cooling input and output pipelines;

[0073] S5. Install the casting mold 8 and inject the heat-conductive casting material 5 into the casting area of ​​the casting mold 8 through the reserved channel on the pressing plate 84 and solidify the entire casting. The specific curing process is as follows: transfer the casting body 7 formed by casting the winding 3 and the water-cooling heat dissipation component 4 together with the casting mold 8 into a curing furnace, maintain the temperature at 80°C for 5 hours, increase the temperature to 100°C for 5 hours, then increase the temperature to 140°C for 14 hours, and then naturally cool down to 100°C.

[0074] S6, take out the winding 3 and water-cooled heat dissipation component 4 cast into one piece from the casting mold 8, insert an iron core column 1 that matches the specifications of the inner mold core 83 into each winding 3, wrap the outside of the casting body 7 with a thermal insulation layer 6, and fix and install iron yokes 2 on the top and bottom of multiple iron core columns 1.

[0075] In one embodiment, after the thermally conductive castable 5 is poured and before it solidifies, the decision to break the vacuum and apply pressure is made based on the equipment's conditions. Specifically, the vacuum is maintained for 30 minutes, followed by breaking the vacuum in the pouring tank and applying pressure to 15 Pa for 15 minutes. The difference between the pouring volume and the void volume is measured and judged. If the difference is greater than a predetermined value, breaking the vacuum and applying pressure is performed.

[0076] In a specific embodiment, the method for winding the winding 3 in the above-mentioned step S1 includes winding the inner winding 31 and the outer winding 32, wherein the winding of the inner winding 31 is performed on a winding mold, and after winding to an appropriate number of turns of the inner winding 31 (for example, after 40%-70% of the total number of turns of the inner winding 31), a water-cooling heat dissipation component 4 is wrapped around and installed on the outside of the coil, and then all the turns of the inner winding 31 are wound on the outside of the water-cooling heat dissipation component 4; a main insulation is placed between the inner winding 31 and the outer winding 32 (the main insulation can be a mesh plate, an airway rod, or a composite insulation), and the outer winding 32 is wound on the outside of the main insulation. After winding to an appropriate number of turns of the outer winding 32 (for example, after 40%-70% of the total number of turns of the outer winding 32), a water-cooling heat dissipation component 4 can be wrapped around and installed on the outside of the coil, and then all the turns of the outer winding 32 are wound on the outside of the water-cooling heat dissipation component 4; and all windings 3 are wound according to the above-mentioned method.

[0077] In another specific embodiment, the method for winding the winding 3 in the above step S1 includes winding the inner winding 31 and the outer winding 32, wherein the winding of the inner winding 31 is performed on a winding mold, and after all the turns of the inner winding 31 are wound; a water-cooled heat dissipation component 4 is installed around the outside of the inner winding 31, and then the outer winding 32 is wound around the outside of the water-cooled heat dissipation component 4; and all windings 3 are wound according to the above method.

[0078] In another specific embodiment, the method for winding the winding 3 in the above-mentioned step S1 includes winding the inner winding 31 and the outer winding 32, wherein the winding of the inner winding 31 is performed on a winding mold, and after winding to an appropriate number of turns of the inner winding 31 (for example, after 40%-70% of the total number of turns of the inner winding 31), a water-cooled heat dissipation component 4 is wrapped around and installed on the outside of the coil, and then all the turns of the inner winding 31 are wound on the outside of the water-cooled heat dissipation component 4; a water-cooled heat dissipation component 4 is wrapped around and installed on the outside of the inner winding 31, and then the outer winding 32 is wound on the outside of the water-cooled heat dissipation component 4, and after winding to an appropriate number of turns of the outer winding 32 (for example, after 40%-70% of the total number of turns of the outer winding 32), a water-cooled heat dissipation component 4 can be wrapped around and installed on the outside of the coil, and then all the turns of the outer winding 32 are wound on the outside of the water-cooled heat dissipation component 4; and all windings 3 are wound according to the above-mentioned method.

[0079] In a specific embodiment, the thermal conductive castable 5 in the above step S2 includes components A and B, component A is epoxy resin plus filler, component B is an acid anhydride curing agent plus filler, and the filler is a ceramic filling material of aluminum oxide (Al2O3) and aluminum nitride (AlN).

[0080] In a specific embodiment, the pouring method of the thermal conductive castable 5 in the above step S5 is:

[0081] The first step is to place the casting mold 8 together with the winding 3 and the corresponding water-cooling heat dissipation component 4 installed therein in a drying and curing furnace, maintain the drying and curing temperature at 100 degrees for 3 hours, then maintain the drying and curing temperature at 80 degrees for 5 hours, and finally maintain the drying and curing temperature at 80 degrees for standby use;

[0082] The second step is to place the dried and solidified casting mold 8 as a whole in the casting equipment, heat it to 80 degrees and then evacuate it to 400Pa;

[0083] The third step is to put the prepared A and B components into the mixing tank of the casting equipment in a ratio of 10:9, heat it to 65 degrees, and evacuate it to 300-400Pa and stir and degas for 40 minutes until the bubbles are completely separated and the casting requirements are met;

[0084] The fourth step is feeding; maintaining the vacuum degree of 300-400Pa, opening the discharge valve, and allowing the mixed material to flow into the casting mold 8. The casting process is controlled within 1 hour.

[0085] Comparative Example 1

[0086] A conventional water-cooled transformer is used as comparative example 1: the water-cooled transformer includes an iron core assembly, a winding, and a water-cooling assembly. The iron core assembly includes three vertical iron core columns, each of which is wrapped around a group of windings. Each winding group includes an inner winding and an outer winding wrapped around the inner winding. The iron core assembly includes the iron core columns and an iron yoke. The water-cooling assembly includes a water-cooling plate and a water-cooling pipe disposed within the water-cooling plate. Since the area of ​​the winding blocked by the upper and lower iron yokes is not convenient for placing a water-cooling plate, the water-cooling plate is placed on both sides of the short side of the winding. Since there is no water-cooling plate along the long side of the winding, in order to enhance the heat dissipation capacity of the winding, a heat dissipation duct for air circulation is added along the long side of the winding to facilitate heat dissipation. Heat dissipation measurements were performed on both under the same test conditions. The test voltage is 400V, the current is 740A, and the test time is 5 hours.

[0087] By comparing the above data, it can be seen that: the transformer in this patent is cast as a whole using a thermally conductive castable 5, which not only reduces the spacing between the windings 3, but also ensures the heat dissipation of the structure of each winding 3, and at the same time can reduce the vibration and noise of the entire transformer; the thermally conductive castable 5 and the water-cooled heat dissipation component 4 ensure the heat dissipation of the structure of each winding 3, while reducing the heat dissipation surface that may dissipate heat to the surrounding area, and at the same time reduces the heat generated by the transformer winding loss to the enclosed space where the transformer is located, and then wraps a layer of thermal insulation layer 6 on the outside of the cast body 7 to further reduce the heat radiation from the outer surface to the space; specifically, the heat directly dissipated to the surrounding space can be reduced to less than 1 / 10 of the original, and the temperature difference inside the winding can be reduced by about 10-20 degrees compared with the method of placing a water-cooled plate on the side, which greatly reduces the volume of the transformer and can reduce the surface temperature of the transformer by 50-80 degrees.

[0088] Example 3

[0089] Based on Example 2, the preparation method of the thermal conductive castable 5 (composite resin) in step S2 includes:

[0090] ① Surface modification of aluminum oxide (Al2O3): Add vacuum-dried Al2O3 powder, a silane coupling agent with a concentration of about 5wt% of the Al2O3 powder, and anhydrous ethanol with a concentration of 10 times the amount of the silane coupling agent to a vacuum reactor. Maintain the temperature at 60°C and perform ultrasonic treatment while stirring for at least 30 minutes. Wash once with anhydrous ethanol and then ultrasonically stir for about 10 minutes. Remove and wash once with ethanol. Filter and then wash two or three times with anhydrous ethanol. Let stand for 30 minutes. Place in a vacuum oven and dry at 80°C for 24 hours. Remove and grind the block into powder, then place in a container for later use.

[0091] The benefits of surface modification of aluminum oxide (Al2O3) are: after surface modification, its surface area changes, making it more dispersible in the matrix, improving its compatibility with the matrix, and improving its thermal conductivity;

[0092] ② Preparation of component A:

[0093] Recipe ratio:

[0094] First, the modified alumina (Al2O3) and aluminum nitride (AlN) are placed in a vacuum oven, dried at 80°C for 24 hours, and then the mixture is preheated to 70-90 degrees Celsius and placed in a reactor. Stir and degas, and gradually evacuate to 300-400 Pa. This process is maintained for 40 minutes to ensure that the mixture is evenly stirred and degassed. The mixture is then placed in a container of material A for later use.

[0095] ③ Preparation of component B:

[0096] Recipe ratio:

[0097] Similarly, the modified alumina (Al2O3) and aluminum nitride (AlN) are placed in a vacuum oven respectively. After drying at 80°C for 24 hours, the mixture in the above proportion is preheated to 70-90 degrees, put into the reactor, stirred and degassed, and gradually vacuumed to 300-400Pa. This process is maintained for 40 minutes to ensure that the mixture is evenly stirred and degassed. The mixture is then placed in the B material container for standby use.

[0098] The particle sizes of aluminum oxide (Al2O3) and aluminum nitride (AlN) in the above-mentioned components A and B are controlled at 100-200 meshes.

[0099] Comparative Example 2

[0100] The surface modification method of aluminum oxide (Al2O3), the preparation method of component A, and the preparation method of component B in the preparation method of thermal conductive castable 5 are consistent with those in Example 2, except that the formula and ratio of component A and component B are inconsistent. Specifically:

[0101] A component formula ratio:

[0102] Formula ratio of component B:

[0103] 41 parts of anhydride curing agent

[0104] Modified alumina (Al2O3) 57 parts

[0105] 2 parts of toughened unsaturated polyester resin.

[0106] In this comparative example, modified alumina is used entirely.

[0107] Comparative Example 3

[0108] The surface modification method of aluminum oxide (Al2O3), the preparation method of component A, and the preparation method of component B in the preparation method of thermal conductive castable 5 are consistent with those in Example 2, except that the formula and ratio of component A and component B are inconsistent. Specifically:

[0109] A component formula ratio:

[0110] Formula ratio of component B:

[0111] In this comparative example, the amount of modified alumina was greatly increased.

[0112] Comparative Example 4

[0113] The thermal conductive castable 5 is made of pure epoxy resin without adding modified alumina and aluminum nitride.

[0114] Comparative Example 5

[0115] The preparation method of component A and component B in the preparation method of thermal conductive castable 5 are consistent with those in Example 2, except that the formula and ratio of component A and component B are inconsistent. Specifically:

[0116] A component formula ratio:

[0117] Formula ratio of component B:

[0118] 41 parts of anhydride curing agent

[0119] Aluminum nitride (AlN) 57 parts

[0120] 2 parts toughened unsaturated polyester resin

[0121] In this comparative example, no modified alumina was used.

[0122] Through the comparison of the above data, it can be seen that the thermal conductivity of the heat-conducting castable 5 prepared by the formula and preparation method of this patent is the highest, especially the thermal conductivity of pure epoxy resin can be increased by about 16 times, which is more conducive to the transfer of heat generated by the winding 3 between the winding 3 and the water-cooled heat dissipation component 4, ensuring the heat dissipation of each winding 3 structure. However, the heat dissipation efficiency of simply using modified alumina, simply using aluminum nitride, and using aluminum oxide as the main component and aluminum nitride as the auxiliary component is not as good as the batching method using aluminum nitride as the main component and modified alumina as the auxiliary component. Therefore, the present invention adopts a batching method using aluminum nitride as the main component and modified alumina as the auxiliary component (that is, the amount of aluminum nitride used is greater than the amount of modified alumina used) to effectively reduce the external radiation of the transformer, so that most of the heat dissipation of the transformer is completed by water cooling, realizing directional heat conduction.

[0123] Obviously, corresponding modifications and / or additions can be made to the above-mentioned method for manufacturing a low-surface thermal radiation transformer without departing from the field and scope of the present invention.

[0124] Those skilled in the art should understand that the various embodiments describe the thermal radiation transformer and the manufacturing method thereof of the present invention from different perspectives, and the various embodiments can be combined with each other.

[0125] It is also clear that although the present invention has described the method for manufacturing the low-surface thermal radiation transformer in detail, those skilled in the art will certainly be able to obtain many other equivalent methods for manufacturing the low-surface thermal radiation transformer, which have the characteristics described in the claims and are therefore within the scope of the protection field defined thereby.

Claims

1. A method for manufacturing a low surface heat radiation transformer, characterized in that: Including: S1. During the winding process of the winding (3), at least part of the components in the water-cooled heat dissipation assembly (4) are wrapped inside the winding (3), leaving the connecting pipelines of the water-cooled heat dissipation assembly (4) and making the connecting pipelines extend outside the winding (3); S2. Prepare the heat-conducting casting material (5) and the casting mold (8) that matches the overall structure of the winding (3) and the water-cooled heat dissipation assembly (4); S3. Install multiple windings (3) and the corresponding water-cooled heat dissipation assemblies (4) into the casting mold (8) at a predetermined interval, and each winding (3) is sleeved on an iron core column mold inside the casting mold (8); S4. Assemble the water-cooled heat dissipation assembly (4) completely, and connect the connecting pipelines extending from each winding (3) to each other or to the water-cooled input and output pipelines; S5. Inject the heat-conducting casting material (5) into the casting mold (8) and cure it integrally; S6. Take out the integrally cast winding (3) and the water-cooled heat dissipation assembly (4) from the casting mold (8), and insert an iron core column (1) that matches the specification of the iron core column mold into each winding (3).

2. The manufacturing method according to claim 1, characterized in that: The winding method of the winding (3) in step S1 includes the winding of the inner winding (31) and the outer winding (32). Among them, the winding of the inner winding (31) is carried out on a winding mold. After the inner winding (31) is wound, a main insulation is arranged outside the inner winding (31), and the outer winding (32) is wound outside the main insulation. During the winding process of the inner winding (31) and the outer winding (32), the water-cooled heat dissipation assembly (4) is wrapped and installed between multiple turns of coils of the inner winding (31) and / or the outer winding (32), and / or the water-cooled heat dissipation assembly (4) is wrapped and installed in the interval between the inner winding (31) and the outer winding (32).

3. The manufacturing method according to claim 1, characterized in that: The water-cooled heat dissipation assembly (4) includes a special-shaped water-cooled plate (41) and a water-cooled pipe (42). At least two of the special-shaped water-cooled plates (41) are assembled to surround part of the inner winding (31) or the outer winding (32) inside them. The water-cooled pipe (42) is arranged in an S shape reciprocally along the length or width direction S of the special-shaped water-cooled plate (41) inside the special-shaped water-cooled plate (41); the two water-cooled pipe ends (43) of the water-cooled pipe (42) extend out of the top or bottom end of the special-shaped water-cooled plate (41) from the short side directions on both sides of the winding (3); the water-cooled pipe ends (43) between adjacent two water-cooled pipes (42) are connected by a connecting pipe (44), and the water-cooled pipe end (43) and the connecting pipe (44) are detachably connected by threaded connection or flange connection or clamp connection.

4. The manufacturing method according to claim 3, characterized in that: The special-shaped water-cooled plate (41) is in a "C" shape, and two "C"-shaped special-shaped water-cooled plates (41) can be assembled into a complete ring to surround part of the inner winding (31) or the outer winding (32) inside them.

5. The manufacturing method according to claim 1, characterized in that: In step S2, the heat-conducting casting material (5) includes components A and B. Component A is epoxy resin plus filler, and component B is acid anhydride curing agent plus filler. The filler uses ceramic filling materials alumina and aluminum nitride; among them, component A includes epoxy resin, modified alumina, and aluminum nitride, and component B includes acid anhydride curing agent, modified alumina, and aluminum nitride, and the amount of aluminum nitride is greater than the amount of modified alumina. Preferably, the preparation method of the thermal conductive castable comprises: ② Surface modification of alumina: Add vacuum-dried alumina powder, 4-6wt% silane coupling agent of alumina powder, and 10 times the amount of anhydrous ethanol of silane coupling agent into a vacuum reactor, keep the temperature at 50-70℃, and Stir and ultrasonically treat for at least 30 minutes, wash once with anhydrous ethanol, and then ultrasonically stir for at least 10 minutes, take out and wash once with ethanol, filter and wash two or three times with anhydrous ethanol, let stand for at least 30 minutes, put in a vacuum oven, dry at 70-90℃ for at least 24 hours, take out and grind the lumps into powder, and then put them in a container for later use; ② Preparation of component A: Recipe ratio: First, the modified alumina and aluminum nitride are placed in a vacuum oven respectively. After drying, the mixture is preheated to 70-90 degrees, put into a reactor, stirred and degassed, and gradually vacuumed. This process is maintained for a predetermined time to make the mixture stirred evenly and degassed, and then put into the A material container for standby use; ③ Preparation of component B: Recipe ratio: First, place the modified alumina and aluminum nitride in a vacuum oven respectively. After drying, preheat the mixture in the above proportion to 70-90 degrees, put it into the reactor, stir and degas, and gradually evacuate to 300-400Pa. This process is maintained for a predetermined time to ensure that the mixture is stirred evenly and degassed. Then, put it into the B material container for standby use.

6. The manufacturing method according to claim 5, characterized in that: The particle sizes of aluminum oxide and aluminum nitride in components A and B are controlled at 100-200 meshes.

7. The manufacturing method according to claim 1, characterized in that: The casting mold (8) described in steps S2 and S3 comprises a bottom plate (81), an outer mold (82), an inner mold core (83) and a pressing plate (84); the outer mold (82) is fixedly arranged on the top surface of the bottom plate (81) so that a closed casting area is formed on the inner side of the outer mold (82); inner mold cores (83) having the same number as the windings (3) are vertically fixedly arranged on the inner side of the outer mold (82) at a certain distance; the wound windings (3) are respectively mounted on the outside of an inner mold core (83), and the water-cooled heat dissipation components (4) between the windings (3) are connected; the pressing plate (84) is fixedly covered on the top surface of the outer mold (82), and a channel for casting into the casting area is reserved on the pressing plate (84).

8. The manufacturing method according to claim 1, characterized in that: The pouring method of the thermal conductive castable (5) in step S5 is: The first step is to place the entire casting mold (8) in a drying and curing furnace, maintain the temperature at 90-110 degrees for drying and curing for 2-4 hours, then maintain the temperature at 70-85 degrees for drying and curing for 4-6 hours, and finally maintain the temperature for standby use; The second step is to place the dried and solidified casting mold (8) as a whole in a casting device, heat it to a second temperature, and then evacuate it; The third step is to put the prepared A and B components into the mixing tank of the pouring equipment in a ratio of 10:9, heat to 60-70 degrees, and vacuum and stir to degas until the bubbles are completely separated to meet the pouring requirements; The fourth step is to feed the materials; maintain the vacuum degree, open the discharge valve, and allow the mixed materials to flow into the casting mold (8). The casting process is controlled within 1 hour.

9. The manufacturing method according to claim 1, characterized in that: In the above step S5, the integrally cast winding (3), water-cooled heat dissipation component (4) and the casting mold (8) are transferred to a curing furnace for curing. The specific curing process is as follows: maintain 70-85 degrees for 3-7 hours, heat up to 90-110 degrees for 3-7 hours, heat up to 140 degrees for 10-18 hours, and naturally cool down to 90-110 degrees. Step S6 also includes wrapping the integral casting body (7) cast by the winding (3) and the water-cooled heat dissipation component (4) with a heat insulation layer (6), and fixing and installing iron yokes (2) on the top and bottom of multiple core columns (1).

10. A transformer manufactured by the manufacturing method according to any one of claims 1 to 9, characterized in that: The transformer comprises an iron core column (1), a winding (3), a water-cooled heat dissipation component (4) and a heat-conducting castable (5); the heat dissipation component (3) is arranged adjacent to at least part of the side surface of each winding (5); the winding (5) and the heat dissipation component (3) are cast into an integral cast body (2) through the castable; the base (4) is fixedly mounted on the bottom of the iron core component (1) and the cast body (2); wherein the heat-conducting castable (5) comprises components A and B; component A comprises epoxy resin plus filler; component B comprises an acid anhydride curing agent plus filler; the filler is a ceramic filling material of alumina and aluminum nitride; wherein component A comprises epoxy resin, modified alumina and aluminum nitride; component B comprises an acid anhydride curing agent, modified alumina and aluminum nitride; wherein the amount of aluminum nitride is greater than the amount of modified alumina.

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