CN115483000B - Compact medium-high frequency transformer - Google Patents

Abstract

The invention discloses a compact medium-high frequency transformer, comprising: the cooling unit comprises a coil component wound by a hollow wire and a cooling plate component provided with a flow passage inside; the coil component is nested in the magnetic core component, and the magnetic core component and the coil component are mutually insulated; the cooling plate assembly is attached to the outer peripheral surface of the magnetic core assembly; the insulating housing is attached to the outer circumferences of the coil assembly and the cooling plate assembly. Through the cooperation of coil assembly and cooling plate subassembly, can take away the heat that magnetic core subassembly and coil assembly produced in time, ensure that each heat source part all has reliable heat dispersion. The compact medium-high frequency transformer has the advantages of compact structure, high integration level, high strength, good heat dissipation performance, safety, reliability and the like.

Description

Compact medium-high frequency transformer

Technical Field

The invention belongs to the technical field of transformers, and particularly relates to a compact medium-high frequency transformer.

Background

The medium-high frequency transformer generates heat due to high switching frequency of the system and high power density of the product, and a large amount of loss is generated in the winding and the magnetic core, so that the reliability of the product is affected. Particularly, when the volume and the weight of the transformer are limited and the voltage class is high, the electromagnetic performance, the weight, the insulating performance and the heat dissipation of the product need to be comprehensively considered, so that the development of the small-sized and light-weighted medium-high-frequency transformer to the high-capacity and high-voltage class is limited.

In order to improve the working performance of the transformer, the coil and the heat dissipation runner of the transformer are respectively arranged as independent parts in the prior art, the coil is a solid conductor, the cold tube is only responsible for heat dissipation, the volume and the weight of the transformer are increased, and the structure cannot be applied to a small-sized light-weight medium-high frequency transformer with the switching frequency of 10kHz because of the huge heat generation of the solid winding.

In the prior art, the transformer is arranged in a box body, a damping design is adopted from top to bottom, the inside of the box body is provided with a magnetic core from inside to outside, then a primary coil and a secondary coil are sleeved, an independent heat dissipation heat pipe and two side wall surfaces are arranged outside the coil, and then a fan is additionally arranged outside to force air cooling for heat dissipation. The transformer has larger product size, various internal devices, and can not realize the insulating effect of epoxy casting under the conditions of limited size and weight and vibration impact test requirement, and reliable insulation among all functional components is difficult to realize.

In addition, in the prior art transformer, the coil and the magnetic core are used for conducting heat to the heat exchange piece at the same time, and then the heat is conducted to the fluid chamber, so that the heat is taken away. The mode needs to be provided with a special heat adsorption chamber and a special heat adsorbent, so that strong electricity is easily brought to a heat dissipation system, and a large potential safety hazard exists.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects of the prior art and providing the compact medium-high frequency transformer which has the advantages of compact structure, high integration level, high strength, good heat dissipation performance, safety and reliability.

In order to solve the technical problems, the invention adopts the following technical scheme:

a compact medium-high frequency transformer comprising: the cooling unit comprises a coil component wound by a hollow wire and a cooling plate component provided with a flow passage inside; the coil assembly is nested inside the magnetic core assembly, the cooling plate assembly is attached to the outer peripheral surface of the magnetic core assembly, and the insulating shell is attached to the peripheries of the coil assembly and the cooling plate assembly.

As a further improvement of the present invention, the magnetic core assembly includes an upper yoke, a bypass yoke, a middle magnetic pillar and a lower yoke, the upper yoke and the lower yoke being respectively located at the top and bottom of the middle magnetic pillar, at least one pillar bypass yoke surrounding the outer periphery of the middle magnetic pillar; the coil assembly is coaxially nested outside the middle magnetic pole and is positioned inside the bypass magnetic yoke.

As a further improvement of the invention, through holes a are arranged among the upper magnet yoke, the middle magnet post and the lower magnet yoke, and the through holes a are used for installing cooling pipelines.

As a further improvement of the invention, the coil assembly comprises a high voltage coil and a low voltage coil, the low voltage coil being nested outside the high voltage coil and the high voltage coil being nested outside the middle pole.

As a further improvement of the invention, the high-voltage coil is provided with a first high-voltage coil connector, a second high-voltage coil connector, a high-voltage coil runner inlet and a high-voltage coil runner outlet; the low-voltage coil is provided with a low-voltage coil runner inlet, a low-voltage coil runner outlet, a first low-voltage coil connector and a second low-voltage coil connector.

As a further improvement of the invention, the cooling plate assembly comprises a cooling top plate and a cooling side plate which are connected with each other, the cooling top plate is attached to the upper magnetic yoke, and a cooling pipe extending into the through hole a is arranged on the cooling top plate; the cooling side plate is attached to the bypass magnetic yoke and the lower magnetic yoke; the number of cooling side plates matches the number of bypass yokes.

As a further improvement of the invention, the cooling top plate is provided with a cooling medium inlet, a cooling medium outlet and a flow regulating valve, and the cooling medium inlet and the cooling medium outlet are communicated with a flow passage in the cooling plate assembly.

As a further improvement of the invention, a cooling unit with a parallel structure is formed among the cooling plate assembly, the high-voltage coil and the low-voltage coil; the flow rate of the cooling medium in the cooling plate assembly and the high-voltage coil is controlled by a flow rate regulating valve.

As a further improvement of the invention, after the magnetic core assembly, the coil assembly and the cooling plate assembly are assembled, insulating materials are poured into the outer contours of the coil assembly, the cooling plate assembly and the bypass magnetic yoke to form an insulating shell integrally so as to realize mutual insulation among the coil assembly, the magnetic core assembly and the cooling plate assembly; and an umbrella skirt assembly used for increasing the creepage distance between the high voltage and the low voltage is arranged outside the insulating shell.

As a further improvement of the invention, the preparation material of the magnetic core component comprises soft magnetic ferrite, amorphous alloy/nanocrystalline or metal magnetic powder cores, and is formed by sticking or splicing a plurality of magnetic core blocks; the coil component is of a spiral structure or a layered structure, and the coil component is made of copper, silver or aluminum; the cooling plate assembly is made of a thermally conductive but magnetically non-conductive material.

Compared with the prior art, the invention has the advantages that:

1. the compact medium-high frequency transformer has the advantages that the magnetic core component plays a role of a magnetic flux loop, and also has the functions of structural strength and adjusting excitation inductance; the coil assembly is wound by adopting the hollow wire, so that the coil assembly has the effects of changing ratio and adjusting leakage inductance, and the internal hollow pipe runner also has the cooling effect; the cooling plate component is attached to the outer peripheral surface of the magnetic core component, and has the functions of ensuring the structural strength and the reliable grounding of each part of the magnetic core component and avoiding the generation of suspension potential besides the cooling function; the insulating housing is arranged on the periphery of the cooling plate assembly, so that reliable insulation of the transformer is realized. All functional components of the transformer integrate multiple functions, and have the advantages of compact structure, high integration level, large capacity and the like. The product of the invention has the maximum power frequency withstand voltage reaching AC85000V,1mi n and leakage inductance less than or equal to 5mA under the conditions of limited volume (300 mm multiplied by 400 mm) and weight (90 kg), and has average temperature rise less than or equal to 80K and hot spot Wen Sheng K under the rated working condition of primary side input voltage of 3600V and switching frequency of 10kHz square wave, thereby well meeting the requirements of withstand voltage and temperature rise and realizing stable operation under medium-high frequency input.

2. According to the compact medium-high frequency transformer, the magnetic core components of the closed loop are obtained by sticking or splicing the plurality of small magnetic cores, the magnetic loop with larger volume is obtained on the premise of ensuring the performance of the magnetic cores, and the development period and the manufacturing cost of the whole product are reduced. And the magnetic core assembly is formed by adopting a mode of sticking or splicing small magnetic cores, so that an air gap can be effectively adjusted, and further, the excitation inductance is adjusted, thereby being beneficial to reducing leakage inductance. Further, the magnetic core assembly obtained by pasting or splicing is favorable for uniformly distributing the air gap into the whole magnetic circuit to form a distributed air gap, so that the situation that the air gap is heated greatly due to the concentration of the air gap and the hot spot concentration and local overheating are avoided.

3. According to the compact medium-high frequency transformer, the cooling plate of the cooling plate assembly is attached to the periphery of the magnetic core assembly, so that heat generated by the magnetic core assembly can be timely taken away. Meanwhile, a cooling pipeline can be installed in the central through hole of the middle magnetic column and connected to the cooling top plate, so that heat of the middle magnetic column is taken away in time. For the coil component, the heat generated by the coil can be timely taken away by introducing a refrigerant medium into the hollow wire of the coil component. Through the cooperation of coil assembly and cooling plate subassembly, take away the heat that magnetic core subassembly and coil assembly produced in time, ensure that each heat source part all has reliable heat dispersion, improved the integrated level and the fail safe nature of transformer.

4. According to the compact medium-high frequency transformer, the cooling plate assembly, the high-voltage coil and the low-voltage coil are designed into the parallel structure, and the cooling plate assembly, the high-voltage coil and the low-voltage coil are matched with the function of the flow regulating valve, so that the refrigerant flow passing through the whole transformer is effectively increased, and the heat dissipation stability of the transformer is improved.

5. According to the compact medium-high frequency transformer, the insulating shell is formed by vacuum casting insulating materials on the outer contours of the coil assembly, the magnetic core assembly and the cooling plate assembly, so that the transformer after casting is integrally formed, the structure is symmetrical, stable operation is facilitated, meanwhile, the compact medium-high frequency transformer is compact in interface, three or more of the compact medium-high frequency transformers can be integrated together for use, leakage inductance among branches is very small, and the problem of unbalance of each branch is avoided. Further, insulating materials are vacuum-cast on the outer contours of the coil assembly, the cooling plate assembly and the bypass magnetic yoke, the contours of the cooling plate assembly and the bypass magnetic yoke are used as the diagonal longest edges of the cast product, and the coil assembly is only required to be wrapped between the adjacent bypass magnetic yokes, so that the weight of the product is effectively reduced by 10% compared with that of the product with the existing square structure on the premise that the overall performance of the product is not affected. In addition, the insulating material for vacuum casting inside the transformer ensures reliable insulation of all functional components, and ensures that all functional components are integrally cast, so that the structural strength of the transformer is improved, and the insulating material can conduct and dissipate heat.

Drawings

Fig. 1 is a schematic diagram of a three-dimensional structure of a magnetic core assembly in a compact medium-high frequency transformer according to the present invention.

Fig. 2 is a schematic diagram of a schematic cross-sectional structure of a magnetic core assembly in a compact medium-high frequency transformer according to the present invention.

Fig. 3 is a schematic diagram of the perspective structure of the coil assembly in the compact medium-high frequency transformer of the present invention.

Fig. 4 is a schematic top view of the coil assembly of the compact medium-high frequency transformer of the present invention.

Fig. 5 is a schematic diagram of the perspective structure of the cooling plate assembly in the compact medium-high frequency transformer of the present invention.

Fig. 6 is a schematic diagram of a side view of a cooling plate assembly in a compact medium-high frequency transformer according to the present invention.

Fig. 7 is a schematic diagram of the internal assembly of the compact medium-high frequency transformer according to the present invention.

Fig. 8 is a schematic diagram of a three-dimensional structure of the compact medium-high frequency transformer according to the present invention after internal assembly.

Fig. 9 is a schematic diagram of a side view of the internal assembly of the compact medium-high frequency transformer of the present invention.

Fig. 10 is a schematic diagram of the three-dimensional structure of the compact medium-high frequency transformer of the present invention.

Fig. 11 is a schematic diagram of a perspective structure of a compact medium-high frequency transformer according to another aspect of the present invention.

Fig. 12 is a schematic diagram of the three-dimensional structure of the compact medium-high frequency transformer in the multi-path integrated use of the invention.

Fig. 13 is a flow chart of an assembling process of the compact medium-high frequency transformer of the invention.

Legend description: 1. a magnetic core assembly; 11. an upper yoke; 12. a bypass yoke; 13. a middle magnetic column; 14. a lower yoke; 2. a coil assembly; 21. a high voltage coil; 211. a first high-voltage coil joint; 212. a second high-voltage coil joint; 213. a high voltage coil flow passage inlet; 214. a high voltage coil flow channel outlet; 22. a low voltage coil; 221. a low voltage coil flow passage inlet; 222. a low voltage coil flow channel outlet; 223. a first low-voltage coil joint; 224. a low-voltage coil joint II; 3. a cooling plate assembly; 31. cooling the top plate; 311. a first cooling runner interface; 312. a cooling runner interface II; 32. cooling the side plates; 33. a cooling medium inlet; 34. a cooling medium outlet; 35. a flow regulating valve; 36. a cooling tube; 4. umbrella skirt band; 5. an annular umbrella skirt; 6. an insulating housing; 7. and (5) mounting holes.

Detailed Description

The invention is further described below in connection with the drawings and the specific preferred embodiments, but the scope of protection of the invention is not limited thereby.

Examples

As shown in fig. 1 to 10, the compact medium-high frequency transformer of the present invention includes: the cooling unit comprises a coil assembly 2 wound by a hollow wire and a cooling plate assembly 3 internally provided with a flow passage, and an insulating shell 6. The coil assembly 2 is nested inside the magnetic core assembly 1, the cooling plate assembly 3 is attached to the outer peripheral surface of the magnetic core assembly 1, and the insulating shell is attached to the outer periphery of the coil assembly 2 and the cooling plate assembly 3. The heat generated by the magnetic core component 1 and the coil component 2 can be taken away in time by introducing refrigerant media into the coil component 2 and the cooling plate component 3, so that the rapid and efficient heat dissipation of the transformer is realized. In this embodiment, the refrigerant medium may be deionized water, freon, or other working medium of cooling liquid or gas.

In this embodiment, the magnetic core assembly 1 is made of soft magnetic ferrite, and a plurality of small magnetic core blocks are adhered into a closed loop through an adhesive, or a plurality of small magnetic core blocks can be fixedly spliced into a closed loop through a structural member. The coil assembly 2 is a spiral structure formed by a hollow copper tube. The field intensity is stronger at the place with large gradient change, which is an insulated weak point, and the round coil sleeve not only ensures the same space between each part, but also makes use of space with maximum efficiency, and forms a typical 'face-face' model, thereby homogenizing the field intensity. The cooling plate assembly 3 is made of an aluminum alloy. The material of the insulating housing 6 may be epoxy. After the magnetic core assembly 1, the coil assembly 2 and the cooling plate assembly 3 in the transformer are assembled, the assembled part is placed in an outer mold, high-heat-conductivity epoxy resin is poured into the mold in a vacuum environment, then the mold is placed in an oven for gradient cooling, the epoxy resin is solidified, and then the mold is taken out, so that a transformer product with the appearance shown in fig. 10 and 11 is finally obtained. It will be appreciated that in other embodiments, the magnetic core assembly 1 may be made of amorphous alloy/nanocrystalline or metal magnetic powder cores; the coil component 2 can adopt a layered structure, and the preparation material of the coil component 2 can be silver or aluminum; the material of the insulating housing 6 may be a heat conductive silicone grease.

In this embodiment, the magnetic core assembly 1 plays a role of both structural strength and adjusting excitation inductance in addition to the role of magnetic flux circuit. The coil component formed by winding the hollow conducting wire is adopted, so that the coil component 2 has the functions of transformation ratio and leakage inductance adjustment, and the internal hollow pipe runner also has the cooling function. The cooling plate assembly 3 is attached to the outer peripheral surface of the magnetic core assembly, and has the functions of ensuring the structural strength and the reliable grounding of each part of the magnetic core assembly and avoiding the generation of suspension potential besides the cooling function. All functional components of the transformer integrate multiple functions, and have the advantages of compact structure, high integration level, large capacity and the like. The product of the invention has the maximum power frequency withstand voltage reaching AC85000V,1mi n and leakage inductance less than or equal to 5mA under the conditions of limited volume (300 mm multiplied by 400 mm) and weight (90 kg), and has average temperature rise less than or equal to 80K and hot spot Wen Sheng K under the rated working condition of primary side input voltage of 3600V and switching frequency of 10kHz square wave, thereby well meeting the requirements of withstand voltage and temperature rise and realizing stable operation under medium-high frequency input.

As shown in fig. 1 and 2, in this embodiment, the magnetic core assembly 1 includes an upper yoke 11, a bypass yoke 12, a middle magnetic pillar 13 and a lower yoke 14, the top and bottom of the middle magnetic pillar 13 are respectively connected with the upper yoke 11 and the lower yoke 14, four pillar bypass yokes 12 are uniformly distributed on the periphery of the middle magnetic pillar 13, the bypass yokes 12 are detachably connected with the upper yoke 11, and the bypass yokes 12 are fixedly connected with the lower yoke 14. The cylindrical middle magnetic pole 13 is enclosed in the space enclosed by the upper magnetic yoke 11, the bypass magnetic yoke 12 and the lower magnetic yoke 14, and the cross section area of the middle magnetic pole 13 of the magnetic core assembly 1 is equal to the sum of the 4 paths of the side magnetic yoke poles, so that the equal cross section area and the equal magnetic density of the whole magnetic circuit are ensured. Because the magnetic core is compact in structure and small in occupied volume, the small-volume magnetic core structural design is well met. The coil assembly 2 is nested coaxially outside the middle leg 13 and inside the bypass yoke 12. Due to the effect of the bypass magnetic yoke 12, leakage of magnetic flux leakage of the coil can be effectively reduced in the process of energizing the coil assembly 2, and influence on the periphery of the transformer is avoided. It will be appreciated that in other embodiments, the middle leg 13 and the bypass yoke 12 may each be provided as multiple legs.

As shown in fig. 1, in this embodiment, through holes a are formed between the upper yoke 11, the middle magnetic pole 13 and the lower yoke 14, and cooling pipes are installed in the through holes a and connected to the cooling plate assembly, so that heat of the middle magnetic pole 13 is timely taken away, and heat dissipation efficiency of the magnetic core assembly is improved.

As shown in fig. 3, the coil assembly 2 includes a high-voltage coil 21 and a low-voltage coil 22, the low-voltage coil 22 being nested outside the high-voltage coil 21, the high-voltage coil 21 being nested outside the middle pole 13. The high-voltage coil 21 and the low-voltage coil 22 are hollow round copper tubes, in particular to double glass fiber covered polyimide film sintered copper pipelines, and the wire diameters of the high-voltage coil 21 and the low-voltage coil 22 and the transformation ratio between the high-voltage coil and the low-voltage coil are actually selected. The cooling system outside forces the refrigerant medium to circulate in the circular copper pipe to take away the heat generated by the winding. It can be appreciated that, since the transformer of the embodiment is applied to the middle-high frequency field, the thickness of the copper pipe wall needs to be reasonably designed according to the practical application situation according to the proximity and skin effect, so that the winding strength and the internal pressure strength can be ensured, and the minimum loss can be ensured. It will be appreciated that in other embodiments, the coil assembly 2 may be wound with three types of coils, i.e., low, medium and high voltage, and the coil assembly 2 may be in the form of a square tube or various types of litz wire co-cooling tubes.

In this embodiment, the high-voltage coil 21 is provided with a first high-voltage coil connector 211, a second high-voltage coil connector 212, a high-voltage coil flow channel inlet 213 and a high-voltage coil flow channel outlet 214. The low-voltage coil 22 is provided with a low-voltage coil flow passage inlet 221, a low-voltage coil flow passage outlet 222, a first low-voltage coil connector 223 and a second low-voltage coil connector 224. The processing mode of the joint position on the coil is to weld by using a copper joint, so that no false welding is ensured, a flow path is smooth, and meanwhile, the side face is welded with a copper or silver braid belt for soft connection, so that the smoothness of an electric loop is ensured.

As shown in fig. 5 to 9, in the present embodiment, the cooling plate assembly 3 includes a cooling top plate 31 and a cooling side plate 32 which are connected to each other, the cooling top plate 31 is attached to the upper yoke 11, the cooling top plate 31 is provided with a cooling pipe 36 extending into the through hole a, and the cooling side plate 32 is attached to the bypass yoke 12 and the lower yoke 14. The number of cooling side plates 32 matches the number of bypass yokes 12, and four columns are provided. In this embodiment, according to the cross-shaped outer contour of the magnetic core assembly 1, the cooling top plate 31 is also set to be cross-shaped, the cooling side plate 32 is set to be L-shaped, so that the bypass yoke 12 and the lower yoke 14 which are fixedly connected can be included, and meanwhile, the volume of the cooling plate assembly 3 can be reduced to the greatest extent on the basis of ensuring the structural strength, so that the overall structure of the transformer is more compact. The heat generated by the magnetic core assembly 1 can be taken away by circulating the refrigerant medium in the flow channel of the cooling plate assembly 3. In this embodiment, in order to avoid heating of the cooling plate assembly 3 caused by the high frequency effect, the cooling plate assembly 3 is made of an aluminum alloy material.

Further, the cooling top plate 31 is provided with a cooling medium inlet 33, a cooling medium outlet 34 and a flow rate regulating valve 35, and the cooling medium inlet 33 and the cooling medium outlet 34 are communicated with a flow passage inside the cooling plate assembly 3. By the action of an external system, the cooling medium flows into the flow channel inside the cooling plate assembly 3 from the cooling medium inlet 33 and flows out from the cooling medium outlet 34, and the cooling medium continuously circulates in the flow channel of the cooling plate assembly 3, so that the heat dissipation efficiency of the magnetic core assembly 1 is improved.

In this embodiment, in order to improve the heat dissipation performance of the transformer, the cooling flow channels among the cooling plate assembly 3, the high-voltage coil 21 and the low-voltage coil 22 adopt a parallel structure, i.e. a cooling unit with a parallel structure is formed. The high-voltage coil runner inlet 213 is in insulation connection with a first cooling runner interface 311 at the bottom of the cooling top plate 31 through a polytetrafluoroethylene pipeline, and the high-voltage coil runner outlet 214 is in insulation connection with a second cooling runner interface 312 at the bottom of the cooling top plate 31 through a polytetrafluoroethylene pipeline. The circulation flow of the cooling medium in the cooling plate assembly 3 and the high-voltage coil 21 is controlled by the flow regulating valve 35, so that the cooling plate assembly is convenient and efficient. The low-voltage coil runner inlet 221 and the low-voltage coil runner outlet 222 of the low-voltage coil 22 are connected with the external flow path of the transformer in an insulating manner, and the cooling runners among the cooling plate assembly 3, the high-voltage coil 21 and the low-voltage coil 22 finally form a parallel structure, so that the flow of refrigerant medium passing through the whole transformer is increased, and meanwhile, each heating source is ensured to realize efficient heat dissipation. Under the rated working conditions that the primary side input voltage is 3600V and the switching frequency is 10kHz square wave, the average temperature rise of the transformer is less than or equal to 80K, and the hot spot is Wen Sheng K.

It should be noted that the transformer of this embodiment needs to have a maximum part of the commercial voltage withstand voltage of AC10000V,1mi n, and a maximum part of the commercial voltage withstand voltage of leakage inductance of 5mA or less for the high-voltage to high-voltage, magnetic core and cooling plate assemblies at a level of AC85000V,1mi n, and a maximum part of the commercial voltage withstand voltage of leakage inductance of 5mA or less under the conditions of a limited volume (300 mm×300mm×400 mm) and a weight (90 kg), and therefore needs to ensure reliable insulation between the high-voltage coil 21, the low-voltage coil 22, the magnetic core assembly 1, and the cooling plate assembly 3.

In this embodiment, in the transformer, first, the coil assembly 2 is designed as a double-cylindrical sleeve, so as to ensure that the distances between the primary and secondary coils are equal everywhere, the insulation distance can be set according to practical application conditions, and the insulation system between the primary and secondary coils mainly depends on the double glass fiber-coated polyimide film, the mesh cloth, the insulation paper, the insulation film and the vacuum filling resin of the coils. Secondly, because the cooling plate assembly 3 is in contact with the magnetic core assembly 1, the cooling plate assembly 3 and the magnetic core assembly 1 are equipotential, and the cooling plate assembly 3 is positioned outside the magnetic core assembly 1, and no additional insulating measure is needed between the cooling plate assembly 3 and the magnetic core assembly 1. Again, the insulation between the coil assembly 2 and the magnetic core assembly 1 requires centering of the coils and strict centrosymmetry, ensuring a safe insulation distance between the low-voltage coil 22 and the bypass yoke 12, and the insulation system is the same as that between the high-voltage coil and the low-voltage coil. According to the distribution characteristic of the electric field, besides the insulation system and the strict insulation distance are arranged between the low-voltage coil 22 and the upper yoke magnet and the lower yoke magnet, two layers of insulation paper and alkali-free glass fiber belts are additionally wrapped at the first turn and the last turn to be tightly drawn. Finally, the high voltage coil 21 is voltage-resistant to the upper and lower yoke magnetic and cooling plate assembly 3 up to AC10000V, where the insulation of the inner coil and the middle pole 13 is mainly required, where the insulation distance can be relatively small, and the insulation system can be referred to as described above. After the magnetic core assembly 1, the coil assembly 2 and the cooling plate assembly 3 are assembled, epoxy resin is vacuum-cast on the outer contours of the coil assembly 2, the cooling plate assembly 3 and the bypass magnetic yoke 12, so that mutual insulation between the high-voltage coil 21 and the low-voltage coil 22 and between the coil assembly 2 and the magnetic core assembly 1 and the cooling plate assembly 3 is realized, the structural strength of the transformer is improved, and the creepage distance of the outer surface of the transformer is increased. That is, the contour of the cooling plate assembly 3 is the diagonally longest side of the cast product, and only the coil assembly needs to be wrapped between adjacent bypass yokes 12, and the final product has a top view similar to a cross shape, and the contour of the cooling top plate 31 is the same. Compared with a square transformer product which is cast without considering the appearance of each component in the transformer, the cross-shaped product obtained by the casting method directly reduces the weight by about 9kg on the premise of not influencing the performance of the transformer, and reduces the weight of the transformer by 10 percent. It will be appreciated that in other embodiments, the outer contours of the coil assembly 2, the cooling plate assembly 3 and the bypass yoke 12 may be filled with epoxy by injection molding, automated pressure gel or room temperature casting.

As shown in fig. 10 to 12, in order to ensure a creepage distance between high voltage and low voltage, an umbrella skirt 4 is provided on the top and side of the insulating housing 6, and an annular umbrella skirt 5 is provided on the side of the insulating housing 6. It will be appreciated that, due to the smaller size of the transformer of this embodiment, the high voltage and the low voltage are placed on two opposite sides of the transformer, the umbrella skirt band 4 is provided on the top and the side of the insulating housing 6 along the direction of the vertical creepage distance, and the annular umbrella skirt 5 is provided around the connector of the low voltage coil and the periphery of the flow passage entrance and exit on the side of the insulating housing 6. The height and the layer type of umbrella skirt structure can be designed and adjusted according to actual demands, the design of the umbrella skirt structure is completed before the design of the mould, and the umbrella skirt structure is integrally formed in the casting process, so that the umbrella skirt structure is convenient and has strong practicability. Meanwhile, mounting holes 7 are reserved around the insulating shell 6, so that the transformer can be mounted and used conveniently. In this embodiment, the shed tape 4, the annular shed 5 and the insulating housing 6 are all epoxy housings. In other embodiments, the shed strip 4, the annular shed 5 and the insulating housing 6 may also be made of other insulating materials.

Fig. 13 shows an assembly process diagram of the compact intermediate frequency transformer of the present embodiment, and the specific operation contents are as follows:

(1) The coil winding is divided into the procedures of die loading, coil winding and die unloading, and finally the coil assembly 2 consisting of a high-voltage coil 21 and a low-voltage coil 22 is produced;

(2) The magnetic core processing is divided into magnetic core cutting and chamfering, magnetic core polishing procedures and finally processing magnetic core components with required shapes;

(3) The magnetic core stacking is to assemble the processed magnetic core components into a whole according to the design of a magnetic circuit, glue or structure members are adopted to compress the magnetic core components, and an opening is reserved, so that the coil is convenient to be sleeved, and the magnetic core strength is ensured to be reliable;

(4) The assembly of the device body is that the coil assembly 2 is coaxially sleeved on the laminated middle magnetic column 13, insulating paper, glass fiber mesh cloth, supporting cushion blocks and the like are added among the components, so that the coil assembly 2 meets the requirements on the magnetic core distance, the high-low voltage coil spacing, the excitation inductance and the leakage inductance, and then the magnetic circuit is closed; simultaneously, the high-voltage coil is connected with the cold plate assembly 3 in an insulating way through a polytetrafluoroethylene pipeline, and the low-voltage coil is connected with an external flow path in an insulating way, so that the flow path is connected while insulation is ensured;

(5) The welding is to weld the high-low voltage coil with the high-low voltage coil electric joint and the flow path joint, so as to ensure the reliable connection of the electric loop and the flow path;

(6) The air tightness test ensures that the whole cold plate runner and the high-low voltage coil runner are reliable and have no welding defects or part defects;

(7) Vacuum casting is divided into the working procedures of mold brushing and demolding agent, outer mold assembling, product pre-baking, vacuum tank filler casting, oven curing, demolding, cleaning and polishing, so that the insulating property and strength of the product are ensured;

(8) And finally ending operation, mounting a nameplate, mounting a grounding mark and the like.

While the invention has been described in terms of preferred embodiments, it is not intended to be limiting. Any person skilled in the art can make many possible variations and modifications to the technical solution of the present invention or equivalent embodiments using the method and technical solution disclosed above without departing from the spirit and technical solution of the present invention. Therefore, any simple modification, equivalent substitution, equivalent variation and modification of the above embodiments according to the technical substance of the present invention, which do not depart from the technical solution of the present invention, still fall within the scope of the technical solution of the present invention.

Claims (8)

1. A compact medium-high frequency transformer, comprising: the cooling unit comprises a coil assembly (2) wound by a hollow wire and a cooling plate assembly (3) with a runner arranged inside; the coil assembly (2) is nested inside the magnetic core assembly (1), the cooling plate assembly (3) is attached to the outer peripheral surface of the magnetic core assembly (1), and the insulating shell is attached to the peripheries of the coil assembly (2) and the cooling plate assembly (3);

the magnetic core assembly (1) comprises an upper magnetic yoke (11), a bypass magnetic yoke (12), a middle magnetic pillar (13) and a lower magnetic yoke (14), wherein the upper magnetic yoke (11) and the lower magnetic yoke (14) are respectively positioned at the top and the bottom of the middle magnetic pillar (13), and at least one pillar of bypass magnetic yoke (12) surrounds the periphery of the middle magnetic pillar (13); the coil component (2) is coaxially nested outside the middle magnetic column (13) and is positioned inside the bypass magnetic yoke (12);

the coil assembly (2) comprises a high-voltage coil (21) and a low-voltage coil (22), wherein the low-voltage coil (22) is nested outside the high-voltage coil (21), and the high-voltage coil (21) is nested outside the middle magnetic column (13).

2. Compact medium-high frequency transformer according to claim 1, characterized in that through holes a are provided between the upper yoke (11), the middle pole (13) and the lower yoke (14), which through holes a are used for mounting cooling pipes.

3. The compact medium-high frequency transformer according to claim 2, wherein the high voltage coil (21) is provided with a first high voltage coil connector (211), a second high voltage coil connector (212), a high voltage coil runner inlet (213) and a high voltage coil runner outlet (214); the low-voltage coil (22) is provided with a low-voltage coil runner inlet (221), a low-voltage coil runner outlet (222), a low-voltage coil joint I (223) and a low-voltage coil joint II (224).

4. A compact medium-high frequency transformer according to claim 2 or 3, characterized in that the cooling plate assembly (3) comprises a cooling top plate (31) and a cooling side plate (32) which are connected with each other, the cooling top plate (31) is attached to the upper yoke (11), and the cooling top plate (31) is provided with a cooling pipe (36) extending into the through hole a; the cooling side plate (32) is attached to the bypass yoke (12) and the lower yoke (14); the number of cooling side plates (32) matches the number of bypass yokes (12).

5. Compact medium-high frequency transformer according to claim 4, characterized in that the cooling top plate (31) is provided with a cooling medium inlet (33), a cooling medium outlet (34) and a flow regulating valve (35), both the cooling medium inlet (33) and the cooling medium outlet (34) being in communication with a flow channel inside the cooling plate assembly (3).

6. Compact medium-high frequency transformer according to claim 5, characterized in that the cooling plate assembly (3), the high voltage coil (21) and the low voltage coil (22) form a cooling unit of parallel structure; the flow rate of the cooling medium in the cooling plate assembly (3) and the high-voltage coil (21) is controlled by a flow rate regulating valve (35).

7. A compact medium-high frequency transformer according to any one of claims 1 to 3, characterized in that after the assembly of the magnetic core assembly (1), the coil assembly (2) and the cooling plate assembly (3), the outer contours of the coil assembly (2), the cooling plate assembly (3) and the bypass yoke (12) are integrally formed with an insulating housing (6) to realize mutual insulation between the coil assembly (2) and the magnetic core assembly (1) and the cooling plate assembly (3); and an umbrella skirt assembly for increasing the creepage distance between high voltage and low voltage is arranged outside the insulating shell (6).

8. A compact medium-high frequency transformer according to any one of claims 1 to 3, characterized in that the magnetic core assembly (1) is made of a preparation material comprising a soft magnetic ferrite, an amorphous alloy/nanocrystalline or a metal magnetic powder core, which is adhered or spliced by a plurality of magnetic core blocks; the coil component (2) is of a spiral structure or a layered structure, and the coil component (2) is made of copper, silver or aluminum; the cooling plate assembly (3) is made of a heat-conducting but non-magnetic material.

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