A high-frequency transformer and its packaging method and use

Abstract

The present invention belongs to the field of transformer packaging technology, and specifically relates to a high-frequency transformer and its packaging method and use. The packaging method is as follows: placing high-frequency transformer accessories in a mold, filling the mold with packaging material, curing, demoulding, cooling to room temperature, and performing temperature treatment; wherein the temperature treatment is performed in any of the following ways: way 1: cooling to -30 to -20 ° C and holding for 1 -24 hours, heating to -10 to -10 ° C and holding for 1 -24 hours, heating to 80 to 120 ° C and holding for 1 -72 hours; way 2: cooling to -30 to -20 ° C and holding for 1 -24 hours, heating to 80 to 120 ° C and holding for 1 -72 hours; way 3: heating to 80 to 120 ° C and holding for 1 -72 hours; way 4: heating to 80 to 120 ° C and holding for 1 -72 hours, cooling to -30 to -20 ° C and holding for 1 -24 hours. The packaging method provided by the present invention performs temperature treatment after curing is completed, which can redistribute the stress in the high-frequency transformer, reduce the electric field distortion caused by stress concentration, reduce partial discharge, and is suitable for the packaging of high-frequency transformers.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer packaging, and in particular to a high-frequency transformer and a packaging method and application thereof. Background Art

[0002] High-frequency transformers are based on power electronic conversion technology and electromagnetic induction principles. They can flexibly realize the flow of electric energy and power quality control. They are key components in DC / DC converters, the core equipment of distributed smart grids, and play a key role in electrical isolation, voltage conversion, and power transmission. High-frequency transformers include iron cores and coils. The iron core and coils need to be encapsulated with packaging materials to achieve insulation and fixation.

[0003] Currently, the most commonly used encapsulation material is epoxy resin. Epoxy resin insulation, as the primary insulating material for high-frequency transformers, offers excellent mechanical properties, high dielectric properties, resistance to surface leakage, and arcing. Using epoxy encapsulation for high-frequency transformers effectively reduces the insulation distance between the high-voltage and low-voltage components, thereby reducing the transformer's size. This also avoids the difficulty of fire protection design associated with conventional oil insulation.

[0004] Prior art discloses a method for encapsulating electronic transformer cores. This involves placing a transformer core composed of multiple high-voltage coils, low-voltage coils, and a magnetic core side by side within the inner cavity of a metal forming mold, with a spacer placed between adjacent transformer cores. The mold is then filled with epoxy resin, heated, and cured to encapsulate the transformer core. However, using epoxy resin to encapsulate high-frequency transformers results in a complex internal structure, resulting in uneven internal stress and electric field distribution, making partial discharge more likely to occur, leading to insulation failure and breakdown. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the prior art in that the internal stress and electric field distribution of the high-frequency transformer after packaging are uneven, local discharge is prone to occur, and then insulation failure and breakdown occur, thereby providing a high-frequency transformer and its packaging method and use.

[0006] To this end, the present invention provides the following technical solutions.

[0007] The present invention provides a high-frequency transformer packaging method, comprising the following steps:

[0008] Place the high-frequency transformer parts in the mold, fill the mold with packaging material, solidify, demould, cool to room temperature, and perform temperature treatment;

[0009] The temperature treatment is performed in any of the following ways:

[0010] Method 1: Cool down to -30-20℃ and keep for 1-24h, then heat up to -10-10℃ and keep for 1-24h, then heat up to 80-120℃ and keep for 1-72h;

[0011] Method 2: Cool down to -30~-20℃, keep for 1~24h, then heat up to 80~120℃, keep for 1~72h;

[0012] Method 3: Raise the temperature to 80-120°C and maintain for 1-72 hours;

[0013] Method 4: Raise the temperature to 80-120°C, maintain for 1-72 hours, then lower the temperature to -30--20°C, maintain for 1-24 hours.

[0014] Optionally, the temperature is lowered to -30 to -20°C at a rate of 5 to 10°C / h; the temperature is raised to -10 to 10°C at a rate of 5 to 10°C / h; and the temperature is raised to 80 to 120°C at a rate of 10 to 20°C / h.

[0015] Optionally, the temperature treatment is performed in any of the following ways:

[0016] Method 1: Cool down to -30-20°C at a rate of 5-10°C / h, maintain for 12-24h, then heat up to -10-10°C at a rate of 5-10°C / h, maintain for 12-24h, then continue to heat up to 80-120°C at a rate of 10-20°C / h, maintain for 24-72h;

[0017] Method 2: Cool down to -30-20°C at a rate of 5-10°C / h, maintain for 12-24 hours, then heat up to 80-120°C at a rate of 10-20°C / h, maintain for 24-72 hours;

[0018] Method 3: Raise the temperature to 80-120°C at a rate of 10-20°C / h and maintain for 24-72h;

[0019] Method 4: Raise the temperature to 80-120°C at a rate of 10-20°C / h, maintain for 24-72h, then cool down to -30--20°C at a rate of 5-10°C / h, maintain for 12-24h.

[0020] Optionally, the curing step further includes a preheating step;

[0021] The preheating temperature is 80-110° C., and the preheating time is 5-20 hours.

[0022] Optionally, the packaging material is subjected to a degassing treatment;

[0023] The degassing temperature is 50-70°C, the degassing pressure is 100-800Pa, and the degassing time is 10-60min.

[0024] Optionally, the packaging material is poured into the mold;

[0025] The pouring temperature is 50-70°C, the pressure is 100-800Pa, the pouring time is 10-60min, and the pressure is maintained for 0-60min after pouring is completed;

[0026] After the pressure holding step, the pressure was increased to 1.5×10 5 Pa~4×10 5 Pa, holding time is 10-60min.

[0027] Optionally, the curing temperature is 70-150° C., and the curing time is 10-24 hours.

[0028] Optionally, the packaging material uses epoxy resin as a curing component; the packaging material also includes conventional components such as fillers and curing agents commonly used in the art, and these components are mixed evenly to form the packaging material. Optionally, the mixing temperature of the packaging material is 50-70°C.

[0029] The present invention provides a high-frequency transformer obtained by the above method.

[0030] The present invention also provides an application of the high-frequency transformer in a flexible substation or a rail locomotive.

[0031] Preferably, the method comprises the following steps:

[0032] 1) Assembling and placing a high-frequency transformer assembly in a mold, wherein the assembly includes an iron core and a coil;

[0033] 2) Preheat the mold at 80-110°C for 5-20 hours;

[0034] 3) Mix the components of the packaging material evenly, and then degas under vacuum at a mixing temperature of 50-70°C, a degassing pressure of 100-800 Pa, and a degassing time of 10-60 minutes;

[0035] 4) Pour the degassed packaging material into the mold under the following pouring conditions: pouring temperature 50-70°C, pressure 100-800 Pa, complete pouring within 10-60 minutes, and maintain the pressure for 0-60 minutes after completion;

[0036] 5) Pressurize to 1.5×10 5 Pa~4×10 5 Pa, maintain for 10 to 60 minutes;

[0037] 6) Curing in stages at 70-150°C for 10-24 hours, demoulding after curing, and allowing the demoulded product to cool to room temperature, i.e., 20-25°C;

[0038] 7) Use any of the following four methods to perform temperature treatment:

[0039] Method 1: Cool down to -30-20°C at a rate of 5-10°C / h, maintain for 1-24h, then heat up to -10-10°C at a rate of 5-10°C / h, maintain for 1-24h, then continue to heat up to 80-120°C at a rate of 10-20°C / h, maintain for 1-72h;

[0040] Method 2: Cool down to -30-20°C at a rate of 5-10°C / h, maintain for 1-24 hours, then heat up to 80-120°C at a rate of 10-20°C / h, maintain for 1-72 hours;

[0041] Method 3: Raise the temperature to 80-120°C at a rate of 10-20°C / h and maintain for 1-72h;

[0042] Method 4: Raise the temperature to 80-120°C at a rate of 10-20°C / h, maintain for 1-72h, then cool down to -30--20°C at a rate of 5-10°C / h, maintain for 1-24h.

[0043] The technical solution of the present invention has the following advantages:

[0044] The high-frequency transformer packaging method provided by the present invention includes placing high-frequency transformer accessories in a mold, filling the mold with a packaging material, curing, demoulding, cooling to room temperature, and performing temperature treatment; wherein the temperature treatment is performed in any one of the following ways: way 1: cooling to -30 to -20°C and maintaining for 1 to 24 hours, heating to -10 to 10°C and maintaining for 1 to 24 hours, heating to 80 to 120°C and maintaining for 1 to 72 hours; way 2: cooling to -30 to -20°C and maintaining for 1 to 24 hours, heating to 80 to 120°C and maintaining for 1 to 72 hours; way 3: heating to 80 to 120°C and maintaining for 1 to 72 hours; way 4: heating to 80 to 120°C and maintaining for 1 to 72 hours, cooling to -30 to -20°C and maintaining for 1 to 24 hours. The packaging method provided by the present invention, after curing, performs a temperature treatment, which can redistribute stress within the high-frequency transformer, reduce electric field distortion caused by stress concentration, and reduce partial discharge. In the temperature treatments of Methods 1 and 2, the temperature is first lowered to shrink the curing material, tightening any pores that may exist at the interfaces of various components within the high-frequency transformer. The temperature is then raised to above the glass transition temperature, softening the curable material and releasing internal stress, thereby reducing porosity and stress distribution defects, and thus reducing partial discharge. This is the most preferred temperature treatment method. The high-frequency transformer manufactured using this method can reduce the power frequency partial discharge value of each phase, measured using the method specified in "22 Partial Discharge (Routine and Special Tests)" of "GB 1094.11-2007 Power Transformers Part 11: Dry-Type Transformers," from 100 to 2000 pC to less than 10 pC, compared to high-frequency transformers not subjected to temperature treatment.

[0045] In addition, compared with method 2, the temperature treatment method 1 of the present invention sets a buffer temperature between cooling and heating to prevent the temperature from rising too fast, which may cause uneven temperature on the back of the high-frequency transformer and crack the epoxy resin material. DETAILED DESCRIPTION

[0046] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0047] In order to solve the deficiencies of the prior art, an object of the present invention is to provide a high-frequency transformer packaging method, a transformer using the packaging method, and uses of the high-frequency transformer.

[0048] The inventors unexpectedly discovered that adding a temperature treatment step after the epoxy resin is cured can redistribute the internal stress of the fully epoxy resin-encapsulated high-frequency transformer, effectively reducing the internal stress and making the internal stress distribution and electric field distribution more uniform, thereby avoiding electric field distortion caused by stress concentration, and avoiding the occurrence of partial discharge and insulation failure breakdown. This has led to the completion of the present invention.

[0049] One aspect of the present invention provides a high-frequency transformer packaging method, comprising the following steps:

[0050] Place the high-frequency transformer parts in the mold, fill the mold with packaging material, solidify, demould, cool to room temperature, and perform temperature treatment;

[0051] The temperature treatment is performed in any of the following ways:

[0052] Method 1: Cool down to -30-20℃ and keep for 1-24h, then heat up to -10-10℃ and keep for 1-24h, then heat up to 80-120℃ and keep for 1-72h;

[0053] Method 2: Cool down to -30~-20℃, keep for 1~24h, then heat up to 80~120℃, keep for 1~72h;

[0054] Method 3: Raise the temperature to 80-120°C and maintain for 1-72 hours;

[0055] Method 4: Raise the temperature to 80-120°C, maintain for 1-72 hours, then lower the temperature to -30--20°C, maintain for 1-24 hours.

[0056] In the present invention, the high-frequency transformer refers to a power transformer whose operating frequency exceeds the medium frequency (10kHz).

[0057] The transformer components are components well known to those skilled in the art. Typical but non-limiting high-frequency transformer components include an iron core, a coil, a cooling water pipe, a mesh cloth, a rubber buffer layer, an insulating tube, a semi-conductive paper, and the like.

[0058] The high-frequency transformer assembly is assembled in a conventional manner in the art.

[0059] After the components are assembled and placed in the mold, the mold is filled with an encapsulation material to achieve the purpose of encapsulation. The encapsulation material includes epoxy resin.

[0060] In the present invention, the encapsulating material is a curable material, which includes an epoxy resin and a necessary curing agent, and may further include other components. The other components can be determined by those skilled in the art based on their own knowledge, such as a curing accelerator, an antioxidant, a light stabilizer, a flame retardant, a filler, a plasticizer, a dye, a pigment, a fungicide, a thixotropic agent, a toughness improver, a defoaming agent, an antistatic agent, a lubricant, an anti-settling agent, a wetting agent, and a release agent. The epoxy resin is a conventional curable epoxy resin in the art.

[0061] The content of each component of the encapsulation material can be determined by those skilled in the art based on their knowledge. A typical, but non-limiting, encapsulation material comprises an epoxy resin premixed with silica filler and a curing agent premixed with silica filler, in a 1:1 mass ratio. The curing agent can be selected to match the selected epoxy resin.

[0062] In the present invention, the method is preferably applicable to a full epoxy encapsulation method for a high-frequency transformer. "Full epoxy encapsulation" means a "non-full encapsulation" structure of a conventional transformer in which the core is not encapsulated in epoxy curing material. In this structure, only the coil is encapsulated in epoxy, and the remaining structure is exposed to the air or only coated with insulating paint.

[0063] In a preferred embodiment of the present invention, after the assembled high-frequency transformer assembly is placed in the mold, the mold is preheated. A typical but non-limiting mold preheating method is: preheating at 80-110°C for 5-20 hours, for example: preheating at 85°C for 20 hours, preheating at 90°C for 15 hours, preheating at 95°C for 15 hours, preheating at 100°C for 20 hours, or preheating at 105°C for 20 hours.

[0064] In a preferred embodiment of the present invention, the uniformly mixed packaging material is degassed before being used to fill the mold. For example, the components of the packaging material can be uniformly mixed and then degassed. The mixing temperature can be, for example, 50 to 70°C. An exemplary degassing method is vacuum degassing. A typical but non-limiting preferred embodiment is: the components of the packaging material are uniformly mixed and then vacuum degassed, the mixing temperature is 50 to 70°C (for example, 53°C, 56°C, 59°C, 62°C, 65°C or 68°C), the pressure during degassing is 100 to 800 Pa, the degassing time is 10 to 60 minutes, and after the vacuum degassing is completed, it is used to fill the mold. In order to improve the mixing and degassing effect, stirring is preferably performed during the degassing process.

[0065] In a preferred embodiment of the present invention, the encapsulating material is poured into the mold to fill the mold. Typical but non-limiting conditions for pouring the encapsulating material are: a pouring temperature of 50-70°C (e.g., 52°C, 54°C, 56°C, 58°C, 60°C, 62°C, 64°C, 66°C, or 68°C) and a pressure of 100-800 Pa (e.g., 150 Pa, 200 Pa, 250 Pa, 300 Pa, 350 Pa, 400 Pa, 450 Pa, 500 Pa, 550 Pa, 600 Pa, 650 Pa, 700 Pa, or 750 Pa). , complete pouring within 10 to 60 minutes (for example, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes or 55 minutes), and maintain the pressure for 0 to 60 minutes (including 0, for example, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes or 55 minutes) after pouring.

[0066] In a preferred embodiment of the present invention, after pouring is completed and the pressure is maintained for 0 to 60 minutes, the pressure is increased to 1.5×10 5 Pa~4×10 5 Pa, maintain for 10 to 60 minutes.

[0067] In a preferred embodiment of the present invention, curing is performed at 70-150°C for 10-24 hours. Preferably, the curing is performed in stages at multiple temperatures for 10-24 hours. A typical, but non-limiting, staged curing method is: curing at 80°C for 4 hours, followed by curing at 140°C for 12 hours. After curing, the product is demolded and allowed to cool to room temperature, i.e., 20-25°C.

[0068] In a preferred embodiment of the present invention, the temperature treatment adopts any one of the following four methods:

[0069] Method 1: Cool down to -30 to -20°C (e.g., -25°C, -20°C, -15°C, -10°C, -5°C, 0°C, 5°C, 10°C, or 15°C) at a rate of 5 to 10°C / h (e.g., 6°C / h, 7°C / h, 8°C / h, or 9°C / h), maintain for 1 to 24 hours (e.g., 5 hours, 10 hours, 15 hours, or 20 hours), then heat up to -10 to 10°C (e.g., 15 hours, 20 hours, 30 hours, 40 hours, 50 hours, 60 hours, 70 hours, 80 hours, or 90 hours) at a rate of 5 to 10°C / h (e.g., 6°C / h, 7°C / h, 8°C / h, or 9°C / h). For example, -5°C, 0°C or 5°C), hold for 1 to 24 hours (for example, 5 hours, 10 hours, 15 hours or 20 hours), continue to increase the temperature at a rate of 10 to 20°C / h (for example, 12°C / h, 14°C / h, 16°C / h or 18°C / h) to 80 to 120°C (for example, 85°C, 90°C, 95°C, 100°C, 105°C, 100°C or 115°C), hold for 1 to 72 hours (for example, 10 hours, 20 hours, 30 hours, 40 hours, 50 hours, 60 hours or 70 hours);

[0070] Mode 2: cooling to -30 to -20°C (e.g., -25°C, -20°C, -15°C, -10°C, -5°C, 0°C, 5°C, 10°C, or 15°C) at a rate of 5 to 10°C / h (e.g., 6°C / h, 7°C / h, 8°C / h, or 9°C / h), maintaining for 1 to 24 hours (e.g., 5 hours, 10 hours, 15 hours, or 20 hours), then heating to 80 to 120°C (e.g., 85°C, 90°C, 95°C, 100°C, 105°C, 100°C, or 115°C) at a rate of 10 to 20°C / h (e.g., 12°C / h, 14°C / h, 16°C / h, or 18°C / h), maintaining for 1 to 72 hours (e.g., 10 hours, 20 hours, 30 hours, 40 hours, 50 hours, 60 hours, or 70 hours);

[0071] Mode 3: heating at a rate of 10-20°C / h (e.g., 12°C / h, 14°C / h, 16°C / h, or 18°C / h) to 80-120°C (e.g., 85°C, 90°C, 95°C, 100°C, 105°C, 100°C, or 115°C), and maintaining for 1-72 h (e.g., 10 h, 20 h, 30 h, 40 h, 50 h, 60 h, or 70 h);

[0072] Method 4: heating to 80-120°C (e.g., 85°C, 90°C, 95°C, 100°C, 105°C, 100°C, or 115°C) at a rate of 10-20°C / h (e.g., 12°C / h, 14°C / h, 16°C / h, or 18°C / h), maintaining for 1-72h (e.g., 10h, 20h, 30h, 40h, 50h, 60h, or 70h), cooling to -30--20°C (e.g., -25°C, -20°C, -15°C, -10°C, -5°C, 0°C, 5°C, 10°C, or 15°C) at a rate of 5-10°C / h (e.g., 6°C / h, 7°C / h, 8°C / h, or 9°C / h), maintaining for 1-24h (e.g., 5h, 10h, 15h, or 20h).

[0073] In the temperature treatment method of method 1 or method 2, the temperature is first lowered to shrink the epoxy resin material, tightening the pores that may exist at the interfaces of various components inside the high-frequency transformer. Then the temperature is raised to above the glass transition temperature of the epoxy resin material to soften it, releasing the internal stress of the epoxy resin material, reducing pore defects and stress distribution defects, and thus reducing the amount of partial discharge.

[0074] Compared with method 2, temperature treatment method 1 sets a buffer temperature between cooling and heating to prevent the temperature from rising too quickly, which may cause uneven temperature on the back of the high-frequency transformer and crack the epoxy resin material.

[0075] In a preferred embodiment of the present invention, mode 1 is preferably performed as follows:

[0076] Cool down to -30-20°C at a rate of 5-10°C / h, maintain for 12-24h, then heat up to -10-10°C at a rate of 5-10°C / h, maintain for 12-24h, then continue to heat up to 80-120°C at a rate of 10-20°C / h, maintain for 24-72h;

[0077] In a preferred embodiment of the present invention, mode 2 is performed as follows:

[0078] Method 2: Cool down to -30-20℃ at a rate of 5-10℃ / h, maintain for 12-24h, then heat up to 80-120℃ at a rate of 10-20℃ / h, maintain for 24-72h.

[0079] In a preferred embodiment of the present invention, mode 3 is performed as follows:

[0080] Method 3: Raise the temperature to 80-120°C at a rate of 10-20°C / h and maintain for 24-72h;

[0081] In a preferred embodiment of the present invention, mode 4 is performed as follows:

[0082] Method 4: Raise the temperature to 80-120°C at a rate of 10-20°C / h, maintain for 24-72h, then cool down to -30--20°C at a rate of 5-10°C / h, maintain for 12-24h.

[0083] In a preferred embodiment of the present invention, the packaging method of the high-frequency transformer includes the following steps:

[0084] 1) Assembling and placing a high-frequency transformer assembly in a mold, wherein the assembly includes an iron core and a coil;

[0085] 2) Preheat the mold at 80-110°C for 5-20 hours;

[0086] 3) Mix the components of the packaging material evenly, and then degas under vacuum at a mixing temperature of 50-70°C, a degassing pressure of 100-800 Pa, and a degassing time of 10-60 minutes;

[0087] 4) Pour the degassed packaging material into the mold under the following pouring conditions: pouring temperature 50-70°C, pressure 100-800 Pa, complete pouring within 10-60 minutes, and maintain the pressure for 0-60 minutes after completion;

[0088] 5) Pressurize to 1.5×10 5 Pa~4×10 5 Pa, maintain for 10 to 60 minutes;

[0089] 6) Curing in stages at 70-150°C for 10-24 hours, demoulding after curing, and allowing the demoulded product to cool to room temperature, i.e., 20-25°C;

[0090] 7) Use any of the following four methods to perform temperature treatment:

[0091] Method 1: Cool down to -30-20°C at a rate of 5-10°C / h, maintain for 1-24h, then heat up to -10-10°C at a rate of 5-10°C / h, maintain for 1-24h, then continue to heat up to 80-120°C at a rate of 10-20°C / h, maintain for 1-72h;

[0092] Method 2: Cool down to -30-20°C at a rate of 5-10°C / h, maintain for 1-24 hours, then heat up to 80-120°C at a rate of 10-20°C / h, maintain for 1-72 hours;

[0093] Method 3: Raise the temperature to 80-120°C at a rate of 10-20°C / h and maintain for 1-72h;

[0094] Method 4: Raise the temperature to 80-120°C at a rate of 10-20°C / h, maintain for 1-72h, then cool down to -30--20°C at a rate of 5-10°C / h, maintain for 1-24h.

[0095] According to another aspect of the present invention, a high-frequency transformer obtained by the method described above is provided.

[0096] According to another aspect of the present invention, there is provided an application of the high-frequency transformer described above in a flexible substation or a railway locomotive.

[0097] In order to facilitate comparison between data, the epoxy resin and curing agent used in the following examples and comparative examples of the present invention adopt the same specifications, and the specific specifications are as follows:

[0098] Epoxy resin was provided by Sethmai (Shanghai) New Material Technology Co., Ltd., model S-214A;

[0099] The curing agent is provided by Saismai (Shanghai) New Material Technology Co., Ltd., model S-214B.

[0100] Example 1

[0101] This embodiment provides a high-frequency transformer packaging method, comprising the following steps:

[0102] 1. Assemble the iron core, coil, cooling water pipe, glass fiber mesh, and semi-conductive paper and place them in a mold. Then preheat the mold at 85°C for 10 hours to obtain a preheated mold.

[0103] 2. Mix the epoxy resin S-214A and curing agent S-214B of Sesmai (Shanghai) New Material Technology Co., Ltd. in a mass ratio of 1:1 at 65°C, and then degas. The degassing pressure is 300Pa and the degassing time is 20min. The degassed packaging material is poured into the preheated mold by pouring at a pouring temperature of 65°C and a pressure of 300Pa. The pouring is completed within 30min. After completion, the pressure is maintained for 30min and the pressure is increased to 2×10 5 Pa, and maintain for 30 min to obtain the filled mold.

[0104] 3. Move the filled mold into a curing oven and cure at 80°C for 4 hours, then heat to 140°C for 12 hours. De-mold after curing, and let the demolded product cool to 25°C. After cooling, cool the high-frequency transformer to -20°C at a rate of 10°C / hour, hold for 1 hour, then heat to -10°C at a rate of 10°C / hour, hold for 2 hours, and continue to heat to 80°C at a rate of 10°C / hour, hold for 1 hour. This completes the packaging of the high-frequency transformer component.

[0105] Example 2

[0106] This embodiment provides a high-frequency transformer packaging method, comprising the following steps:

[0107] 1. Assemble the iron core and coil and place them in a mold, then preheat the mold at 90°C for 15 hours to obtain a preheated mold;

[0108] 2. The epoxy resin S-214A and curing agent S-214B of Saismai (Shanghai) New Material Technology Co., Ltd. were mixed at a mass ratio of 1:1 at 70°C and then degassed at a pressure of 800 Pa for 10 minutes. The degassed packaging material was poured into the preheated mold at a temperature of 70°C and a pressure of 800 Pa within 60 minutes. After completion, the pressure was maintained for 60 minutes and the pressure was increased to 1.5×10 5 Pa, and maintain for 10 min to obtain the filled mold.

[0109] 3. Move the filled mold into a curing oven and cure at 70°C for 4 hours, then raise the temperature to 130°C for 20 hours. De-mold the mold after curing, and let the demolded product cool to 23°C. After cooling, cool the high-frequency transformer to -30°C at a rate of 10°C / hour, hold for 1 hour, then raise the temperature to 120°C at a rate of 20°C / hour and hold for 2 hours. This completes the packaging of the high-frequency transformer assembly.

[0110] Example 3

[0111] This embodiment provides a high-frequency transformer packaging method, comprising the following steps:

[0112] 1. Assemble the iron core, coil, cooling water pipe, and glass fiber mesh cloth and place them in a mold. Then preheat the mold at 95°C for 12 hours to obtain a preheated mold.

[0113] 2. The epoxy resin S-214A and curing agent S-214B of Sesmai (Shanghai) New Material Technology Co., Ltd. were mixed at a mass ratio of 1:1 at 70°C and then degassed at a pressure of 100 Pa for 20 minutes. The degassed packaging material was poured into the preheated mold at a temperature of 66°C and a pressure of 530 Pa within 35 minutes. After completion, the pressure was maintained for 35 minutes and the pressure was increased to 3×10 5 Pa, and maintain for 30 min to obtain the filled mold.

[0114] 3. Move the filled mold into a curing oven and cure at 90°C for 3 hours, then raise the temperature to 150°C for 7 hours. After curing, demould the mold and let the demoulded product cool to 20°C. After cooling, heat the high-frequency transformer at a rate of 20°C / hour to 117°C and maintain this temperature for 32 hours. This completes the packaging of the high-frequency transformer assembly.

[0115] Example 4

[0116] This embodiment provides a high-frequency transformer packaging method, comprising the following steps:

[0117] 1. Assemble the iron core, coil, glass fiber mesh, and semi-conductive paper and place them in a mold, then preheat the mold at 80°C for 20 hours to obtain a preheated mold;

[0118] 2. The epoxy resin S-214A and curing agent S-214B of Sesmai (Shanghai) New Material Technology Co., Ltd. were mixed at a mass ratio of 1:1 at 70°C and then degassed at a pressure of 100 Pa for 60 minutes. The degassed packaging material was poured into the preheated mold at a temperature of 70°C and a pressure of 100 Pa within 60 minutes. After completion, the pressure was maintained for 60 minutes and the pressure was increased to 2.5×10 5 Pa, and maintained for 55 min to obtain the filled mold.

[0119] 3. Move the filled mold into a curing oven and cure at 90°C for 4 hours, then raise the temperature to 130°C for 14 hours. After curing, demold the mold and let the demolded product cool to 22°C. After cooling, heat the high-frequency transformer to 120°C at a rate of 18°C / hour, hold for 3 hours, then cool to -20°C at a rate of 8°C / hour and hold for 3 hours. This completes the packaging of the high-frequency transformer assembly.

[0120] Example 5

[0121] This embodiment provides a high-frequency transformer packaging method, comprising the following steps:

[0122] 1. Assemble the iron core, coil, cooling water pipe, glass fiber mesh, and semi-conductive paper and place them in a mold. Then preheat the mold at 85°C for 10 hours to obtain a preheated mold.

[0123] 2. Mix the epoxy resin S-214A and curing agent S-214B of Sesmai (Shanghai) New Material Technology Co., Ltd. in a mass ratio of 1:1 at 65°C, and then degas. The degassing pressure is 300Pa and the degassing time is 20min. The degassed packaging material is poured into the preheated mold by pouring at a pouring temperature of 65°C and a pressure of 300Pa. The pouring is completed within 30min. After completion, the pressure is maintained for 30min and the pressure is increased to 2×10 5 Pa, and maintain for 30 min to obtain the filled mold.

[0124] 3. Move the filled mold into the curing oven, cure at 80℃ for 4h, then heat to 140℃ for 12h, demould after curing, and let the demoulded product stand and cool to 25℃; after cooling, cool the high-frequency transformer to -25℃ at a rate of 5℃ / h, hold for 12h, then heat to -5℃ at a rate of 5℃ / h, hold for 12h, and continue to heat to 110℃ at a rate of 10℃ / h and hold for 24h.

[0125] Example 6

[0126] This embodiment provides a high-frequency transformer packaging method, comprising the following steps:

[0127] 1. Assemble the iron core and coil and place them in a mold, then preheat the mold at 90°C for 15 hours to obtain a preheated mold;

[0128] 2. The epoxy resin S-214A and curing agent S-214B of Saismai (Shanghai) New Material Technology Co., Ltd. were mixed at a mass ratio of 1:1 at 70°C and then degassed at a pressure of 800 Pa for 10 minutes. The degassed packaging material was poured into the preheated mold at a temperature of 70°C and a pressure of 800 Pa within 60 minutes. After completion, the pressure was maintained for 60 minutes and the pressure was increased to 1.5×10 5 Pa, hold for 10 min to obtain the filled mold.

[0129] 3. Move the filled mold into a curing oven and cure at 70°C for 4 hours, then raise the temperature to 130°C for 20 hours. After curing, demould the mold and let the demoulded product cool to 23°C. After cooling, cool the high-frequency transformer to -25°C at a rate of 5°C / hour and hold for 12 hours. Then, raise the temperature to 110°C at a rate of 10°C / hour and hold for 24 hours. This completes the packaging of the high-frequency transformer assembly.

[0130] Example 7

[0131] This embodiment provides a high-frequency transformer packaging method, comprising the following steps:

[0132] 1. Assemble the iron core, coil, cooling water pipe, and glass fiber mesh cloth and place them in a mold. Then preheat the mold at 95°C for 12 hours to obtain a preheated mold.

[0133] 2. The epoxy resin S-214A and curing agent S-214B of Sesmai (Shanghai) New Material Technology Co., Ltd. were mixed at a mass ratio of 1:1 at 70°C and then degassed at a pressure of 100 Pa for 20 minutes. The degassed packaging material was poured into the preheated mold at a temperature of 66°C and a pressure of 530 Pa within 35 minutes. After completion, the pressure was maintained for 35 minutes and the pressure was increased to 3×10 5 Pa, and maintain for 30 min to obtain the filled mold.

[0134] 3. Move the filled mold into a curing oven and cure at 90°C for 3 hours, then raise the temperature to 150°C for 7 hours. After curing, demould the mold and let the demoulded product cool to 20°C. After cooling, heat the high-frequency transformer at a rate of 10°C / hour to 110°C and maintain this temperature for 24 hours. This completes the packaging of the high-frequency transformer assembly.

[0135] Example 8

[0136] This embodiment provides a high-frequency transformer packaging method, comprising the following steps:

[0137] 1. Assemble the iron core, coil, glass fiber mesh, and semi-conductive paper and place them in a mold, then preheat the mold at 80°C for 20 hours to obtain a preheated mold;

[0138] 2. The epoxy resin S-214A and curing agent S-214B of Sesmai (Shanghai) New Material Technology Co., Ltd. were mixed at a mass ratio of 1:1 at 70°C and then degassed at a pressure of 100 Pa for 60 minutes. The degassed packaging material was poured into the preheated mold at a temperature of 70°C and a pressure of 100 Pa within 60 minutes. After completion, the pressure was maintained for 60 minutes and the pressure was increased to 2.5×10 5 Pa, and maintained for 55 min to obtain the filled mold.

[0139] 3. Move the filled mold into a curing oven and cure at 90°C for 4 hours, then raise the temperature to 130°C for 14 hours. After curing, demold the mold and let the demolded product cool to 22°C. After cooling, heat the high-frequency transformer to 110°C at a rate of 10°C / hour, hold for 24 hours, then cool to -25°C at a rate of 5°C / hour and hold for 12 hours. This completes the packaging of the high-frequency transformer assembly.

[0140] Example 9

[0141] This embodiment provides a high-frequency transformer packaging method, comprising the following steps:

[0142] 1. Assemble the iron core, coil, cooling water pipe, glass fiber mesh, and semi-conductive paper and place them in a mold. Then preheat the mold at 85°C for 10 hours to obtain a preheated mold.

[0143] 2. Mix the epoxy resin S-214A and curing agent S-214B of Sesmai (Shanghai) New Material Technology Co., Ltd. in a mass ratio of 1:1 at 65°C, and then degas. The degassing pressure is 300Pa and the degassing time is 20min. The degassed packaging material is poured into the preheated mold by pouring at a pouring temperature of 65°C and a pressure of 300Pa. The pouring is completed within 30min. After completion, the pressure is maintained for 30min and the pressure is increased to 2×10 5 Pa, and maintain for 30 min to obtain the filled mold.

[0144] 3. Move the filled mold into a curing oven and cure at 80°C for 4 hours, then heat to 140°C for 12 hours. De-mold after curing, and let the demolded product cool to 25°C. After cooling, cool the high-frequency transformer to -17°C at a rate of 12°C / hour, hold for 1 hour, then heat to -15°C at a rate of 12°C / hour, hold for 1 hour, and then continue to heat to 70°C at a rate of 25°C / hour and hold for 0.5 hours. This completes the packaging of the high-frequency transformer component.

[0145] Example 10

[0146] This embodiment provides a high-frequency transformer packaging method, comprising the following steps:

[0147] 1. Assemble the iron core and coil and place them in a mold, then preheat the mold at 90°C for 15 hours to obtain a preheated mold;

[0148] 2. The epoxy resin S-214A and curing agent S-214B of Saismai (Shanghai) New Material Technology Co., Ltd. were mixed at a mass ratio of 1:1 at 70°C and then degassed at a pressure of 800 Pa for 10 minutes. The degassed packaging material was poured into the preheated mold at a temperature of 70°C and a pressure of 800 Pa within 60 minutes. After completion, the pressure was maintained for 60 minutes and the pressure was increased to 1.5×10 5 Pa, and maintain for 10 min to obtain the filled mold.

[0149] 3. Move the filled mold into a curing oven and cure at 70°C for 4 hours, then raise the temperature to 130°C for 20 hours. After curing, demold the mold and let the demolded product cool to 23°C. After cooling, cool the high-frequency transformer to -17°C at a rate of 12°C / hour, hold for 1 hour, then raise the temperature to 70°C at a rate of 25°C / hour and hold for 0.5 hours. This completes the packaging of the high-frequency transformer assembly.

[0150] Example 11

[0151] This embodiment provides a high-frequency transformer packaging method, comprising the following steps:

[0152] 1. Assemble the iron core, coil, cooling water pipe, and glass fiber mesh cloth and place them in a mold. Then preheat the mold at 95°C for 12 hours to obtain a preheated mold.

[0153] 2. The epoxy resin S-214A and curing agent S-214B of Sesmai (Shanghai) New Material Technology Co., Ltd. were mixed at a mass ratio of 1:1 at 70°C and then degassed at a pressure of 100 Pa for 20 minutes. The degassed packaging material was poured into the preheated mold at a temperature of 66°C and a pressure of 530 Pa within 35 minutes. After completion, the pressure was maintained for 35 minutes and the pressure was increased to 3×10 5 Pa, and maintain for 30 min to obtain the filled mold.

[0154] 3. Move the filled mold into a curing oven and cure at 90°C for 3 hours, then raise the temperature to 150°C for 7 hours. After curing, demould the mold and let the demoulded product cool to 20°C. After cooling, heat the high-frequency transformer at a rate of 27°C / hour to 130°C and hold for 3 hours. This completes the packaging of the high-frequency transformer assembly.

[0155] Example 12

[0156] This embodiment provides a high-frequency transformer packaging method, comprising the following steps:

[0157] 1. Assemble the iron core, coil, glass fiber mesh, and semi-conductive paper and place them in a mold, then preheat the mold at 80°C for 20 hours to obtain a preheated mold;

[0158] 2. The epoxy resin S-214A and curing agent S-214B of Sesmai (Shanghai) New Material Technology Co., Ltd. were mixed at a mass ratio of 1:1 at 70°C and then degassed at a pressure of 100 Pa for 60 minutes. The degassed packaging material was poured into the preheated mold at a temperature of 70°C and a pressure of 100 Pa within 60 minutes. After completion, the pressure was maintained for 60 minutes and the pressure was increased to 2.5×10 5 Pa, and maintained for 55 min to obtain the filled mold.

[0159] 3. Move the filled mold into a curing oven and cure at 90°C for 4 hours, then raise the temperature to 130°C for 14 hours. After curing, demold the mold and let the demolded product cool to 22°C. After cooling, heat the high-frequency transformer to 130°C at a rate of 24°C / hour, hold for 3 hours, then cool to -34°C at a rate of 12°C / hour and hold for 0.3 hours. This completes the packaging of the high-frequency transformer assembly.

[0160] Comparative Example 1

[0161] This comparative example provides a high-frequency transformer packaging method, comprising the following steps:

[0162] 1. Assemble the iron core, coil, cooling water pipe, glass fiber mesh, and semi-conductive paper and place them in a mold. Then preheat the mold at 85°C for 10 hours to obtain a preheated mold.

[0163] 2. Mix the epoxy resin S-214A and curing agent S-214B of Sesmai (Shanghai) New Material Technology Co., Ltd. in a mass ratio of 1:1 at 65°C, and then degas. The degassing pressure is 300Pa and the degassing time is 20min. The degassed packaging material is poured into the preheated mold by pouring at a pouring temperature of 65°C and a pressure of 300Pa. The pouring is completed within 30min. After completion, the pressure is maintained for 30min and the pressure is increased to 2×10 5 Pa, and maintain for 30 min to obtain the filled mold.

[0164] 3. Move the filled mold into a curing oven and cure at 80°C for 4 hours, then heat to 140°C for 12 hours. De-mold the mold after curing, and let the demoulded product cool to 25°C. This completes the packaging of the high-frequency transformer assembly.

[0165] Comparative Example 2

[0166] This comparative example provides a high-frequency transformer packaging method, comprising the following steps:

[0167] 1. Assemble the iron core and coil and place them in a mold, then preheat the mold at 90°C for 15 hours to obtain a preheated mold;

[0168] 2. The epoxy resin S-214A and curing agent S-214B of Saismai (Shanghai) New Material Technology Co., Ltd. were mixed at a mass ratio of 1:1 at 70°C and then degassed at a pressure of 800 Pa for 10 minutes. The degassed packaging material was poured into the preheated mold at a temperature of 70°C and a pressure of 800 Pa within 60 minutes. After completion, the pressure was maintained for 60 minutes and the pressure was increased to 1.5×10 5 Pa, and maintain for 10 min to obtain the filled mold.

[0169] 3. Move the filled mold into a curing oven and cure at 70°C for 4 hours, then heat to 130°C for 20 hours. De-mold the mold after curing, and let the demoulded product cool to 23°C. This completes the packaging of the high-frequency transformer assembly.

[0170] Comparative Example 3

[0171] This comparative example provides a high-frequency transformer packaging method, comprising the following steps:

[0172] 1. Assemble the iron core, coil, cooling water pipe, and glass fiber mesh cloth and place them in a mold. Then preheat the mold at 95°C for 12 hours to obtain a preheated mold.

[0173] 2. The epoxy resin S-214A and curing agent S-214B of Sesmai (Shanghai) New Material Technology Co., Ltd. were mixed at a mass ratio of 1:1 at 70°C and then degassed at a pressure of 100 Pa for 20 minutes. The degassed packaging material was poured into the preheated mold at a temperature of 66°C and a pressure of 530 Pa within 35 minutes. After completion, the pressure was maintained for 35 minutes and the pressure was increased to 3×10 5 Pa, and maintain for 30 min to obtain the filled mold.

[0174] 3. Move the filled mold into a curing oven and cure at 90°C for 3 hours, then heat to 150°C for 7 hours. De-mold the mold after curing, and let the demoulded product cool to 20°C. This completes the packaging of the high-frequency transformer assembly.

[0175] Comparative Example 4

[0176] This comparative example provides a high-frequency transformer packaging method, comprising the following steps:

[0177] 1. Assemble the iron core, coil, glass fiber mesh, and semi-conductive paper and place them in a mold, then preheat the mold at 80°C for 20 hours to obtain a preheated mold;

[0178] 2. The epoxy resin S-214A and curing agent S-214B of Sesmai (Shanghai) New Material Technology Co., Ltd. were mixed at a mass ratio of 1:1 at 70°C and then degassed at a pressure of 100 Pa for 60 minutes. The degassed packaging material was poured into the preheated mold at a temperature of 70°C and a pressure of 100 Pa within 60 minutes. After completion, the pressure was maintained for 60 minutes and the pressure was increased to 2.5×10 5 Pa, and maintained for 55 min to obtain the filled mold.

[0179] 3. Move the filled mold into a curing oven and cure at 90°C for 4 hours, then heat to 130°C for 14 hours. De-mold the mold after curing, and let the demoulded product cool to 22°C. This completes the packaging of the high-frequency transformer assembly.

[0180] The high-frequency transformers of Examples 1-12 and Comparative Examples 1-4 were subjected to power-frequency partial discharge testing using the method specified in "22 Partial Discharge (Routine and Special Tests)" of "GB 1094.11-2007 Power High-Frequency Transformers - Part 11: Dry-Type High-Frequency Transformers." The test results are shown in Table 1.

[0181] Table 1:

[0182] Test results (unit: pC) Example 1 4 Example 2 4 Example 3 9 Example 4 7 Example 5 2 Example 6 3 Example 7 6 Example 8 5 Example 9 26 Example 10 36 Example 11 84 Example 12 53 Comparative Example 1 129 Comparative Example 2 258 Comparative Example 3 1530 Comparative Example 4 165

[0183] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A high-frequency transformer packaging method, characterized in that: The following steps are involved: The high-frequency transformer parts are placed in a mold, the mold is filled with a packaging material, cured, demoulded, cooled to room temperature, and subjected to temperature treatment; the packaging material uses epoxy resin as a curing component; The temperature treatment is performed in any of the following ways: Method 1: Cool down to -30~-20℃ and keep for 1-24h, then heat up to -10~10℃ and keep for 1-24h, then heat up to 80-120℃ and keep for 1-72h; Method 2: Cool down to -30~-20℃, maintain for 1~24h, then heat up to 80~120℃, maintain for 1~72h; Method 3: Raise the temperature to 80-120°C and maintain for 1-72 hours; Method 4: Raise the temperature to 80~120℃, maintain for 1~72h, then lower the temperature to -30~-20℃, maintain for 1~24h.

2. The high-frequency transformer packaging method according to claim 1, characterized in that: Cool down to -30~-20℃ at a rate of 5-10℃ / h; heat up to -10~10℃ at a rate of 5-10℃ / h; heat up to 80-120℃ at a rate of 10-20℃ / h.

3. The high-frequency transformer packaging method according to claim 2, characterized in that: The temperature treatment is performed in any of the following ways: Method 1: Cool down to -30~-20℃ at a rate of 5~10℃ / h, maintain for 12~24h, then heat up to -10~10℃ at a rate of 5~10℃ / h, maintain for 12~24h, then continue to heat up to 80~120℃ at a rate of 10~20℃ / h, maintain for 24~72h; Method 2: Cool down to -30~-20℃ at a rate of 5~10℃ / h, maintain for 12~24h, then heat up to 80~120℃ at a rate of 10~20℃ / h, maintain for 24~72h; Method 3: Raise the temperature to 80-120°C at a rate of 10-20°C / h and maintain for 24-72h; Method 4: Raise the temperature to 80~120℃ at a rate of 10~20℃ / h, maintain for 24~72h, then cool down to -30~-20℃ at a rate of 5~10℃ / h, maintain for 12~24h.

4. The high-frequency transformer packaging method according to claim 1, characterized in that: The curing step also includes a preheating step; The preheating temperature is 80-110° C., and the preheating time is 5-20 hours.

5. The high-frequency transformer packaging method according to claim 1, characterized in that: Degassing the packaging material; The degassing temperature is 50-70°C, the degassing pressure is 100-800Pa, and the degassing time is 10-60min.

6. The high-frequency transformer packaging method according to claim 1, characterized in that: The packaging material is poured into the mold; The pouring temperature is 50-70°C, the pressure is 100-800Pa, the pouring time is 10-60min, and the pressure is maintained for 0-60min after pouring is completed; After the pressure holding step, the pressure was increased to 1.5×10 5 Pa~4×10 5 Pa, holding time is 10-60min.

7. The high-frequency transformer packaging method according to claim 1, characterized in that: The curing temperature is 70-150° C., and the curing time is 10-24 hours.

8. A high-frequency transformer obtained by the method according to any one of claims 1 to 7.

9. Use of the high-frequency transformer according to claim 8 in a flexible substation or a rail locomotive.