Half-potting grounding litz wire shielding type high-voltage and high-frequency transformer structure

Abstract

The invention discloses a semi-potting grounding litz wire shielding type high-voltage and high-frequency transformer structure, which adopts a litz wire air gap electric field shielding scheme, and realizes that electric fields between a high-voltage winding and a magnetic core window and between the high-voltage winding and a low-voltage winding are concentrated in a potting area by winding a litz wire into a shielding layer. The Litz wire winding mode is flexibly arranged according to the main magnetic flux density of the magnetic core and the actual design requirement, the Litz wire is mainly wound in the window direction of the magnetic core, and meanwhile the Litz wire can be arranged in parallel to the conductor. The high-voltage winding is formed by winding a litz wire on a first epoxy framework and is provided with a grounded litz wire shielding layer, so that stable electric field isolation is formed between the high-voltage winding and the magnetic core window as well as between the high-voltage winding and the low-voltage winding; and the low-voltage winding is wound on the second epoxy skeleton and is covered by the second encapsulation layer.

Description

Technical Field

[0001] The present invention belongs to the technical field of power electronic transformer application, and relates to a high-voltage and high-frequency transformer, in particular to a semi-potted grounded Litz wire shielded high-voltage and high-frequency transformer structure. Background Art

[0002] In power electronic converters, high-frequency transformers are key components for voltage conversion and electrical isolation. They are widely used in modern energy systems (such as photovoltaics and energy storage systems) for efficient access and conversion of large-capacity DC sources. Compared to traditional power-frequency transformers, high-frequency transformers utilize higher operating frequencies to achieve higher power density and more compact structures, meeting the demands for miniaturization, lightweighting, and efficient control. However, traditional power-frequency transformers, due to their low frequency, often suffer from bulky cores, low power density, and complex control.

[0003] As operating frequencies increase, transformer size decreases significantly, leading to higher power density. However, this also significantly reduces heat dissipation area, increasing loss density and resulting in excessive temperature rise, a major technical challenge for high-frequency transformers. In particular, in applications with isolation voltages of 10 kV or higher, creepage distances and air clearances between various components within the high-frequency transformer (such as the primary winding, secondary winding, and core) complicate insulation design. To meet these high insulation requirements, existing dry-type transformers typically employ either full potting or semi-potting with a partially exposed yoke. Full potting technology completely encapsulates the windings, core, and other components within the transformer, ensuring a uniform and continuous insulation layer between components, resulting in excellent overall insulation performance and structural stability. However, this completely enclosed design hinders internal heat dissipation, easily causing excessive temperature rise and negatively impacting the dielectric properties of the insulation material. Furthermore, if a partial failure in the fully potted structure occurs, repair typically requires replacement of the entire potting unit, resulting in high repair costs and downtime, while also increasing overall weight and manufacturing costs.

[0004] While meeting insulation requirements, the semi-potting technology, which exposes a portion of the iron yoke, exposes part of the magnetic core and air duct to enhance heat dissipation, significantly improving internal heat dissipation performance and reducing the risk of temperature rise. However, the magnetic core is still potted together with the windings, and local damage requires replacement of the entire corresponding potting module. While this reduces repair costs and maintenance cycles, it is still not flexible. Moreover, since only a portion of the area is potted, the semi-potting design requires precise control of the insulation structure to prevent local electric field unevenness and partial discharge problems. At the same time, the overall insulation design and processing technology are relatively more complex. For example, in the "semi-potted transparent high-voltage and high-frequency transformer structure" disclosed in CN110323043 B, the high and low voltage windings are typically potted separately, with a certain air gap between them to facilitate heat dissipation and structural layout. However, while this air gap helps effectively dissipate heat, it also significantly increases the insulation distance requirements between the two windings. As an insulating medium, air has a lower dielectric strength than the potting material, which easily forms local high electric field areas at the edges, increasing the risk of partial discharge. Partial potting only pots the high-voltage winding, and does not pot the low-voltage winding. There is an air gap between the high and low voltage windings. Such a design can easily lead to uneven electric field distribution. In order to meet the high-voltage insulation requirements, it is often necessary to increase the air gap between the high and low voltage windings. This not only increases the insulation distance requirements, but also easily leads to local electric field concentration, increasing the risk of partial discharge. At the same time, this structure pots the winding and the magnetic core together. In case of damage, the winding and the magnetic core still need to be replaced together.

[0005] The information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the Invention

[0006] To address the shortcomings or defects of the aforementioned prior art, a semi-potted grounded Litz wire-shielded high-voltage, high-frequency transformer structure is provided. By potting the high- and low-voltage windings separately and then assembling them with a magnetic core unit to form a modular structure, and providing an air gap electric field shielding layer composed of grounded Litz wire on the inside and outside of the high-voltage winding, the high-frequency electric field is primarily concentrated in the epoxy resin potting layer, effectively reducing the risk of partial discharge and insulation stress, while significantly improving heat dissipation performance. In the event of module damage, only the damaged portion can be replaced, addressing the shortcomings of prior art solutions in terms of heat dissipation, insulation, and ease of maintenance.

[0007] The purpose of the present invention is achieved through the following technical solutions.

[0008] A semi-potted grounded Litz wire shielded high-voltage and high-frequency transformer structure includes:

[0009] Magnetic core module;

[0010] A high-voltage winding module, comprising:

[0011] The first epoxy skeleton,

[0012] High voltage winding, which is wound on the first epoxy frame via Litz wire,

[0013] The shielding layer is made of grounded Litz wire, and the shielding layer forms a complete coverage between the high-voltage winding and the iron yoke, and between the high-voltage winding and the low-voltage winding.

[0014] a first potting layer covering the high-voltage winding and the shielding layer to form a potted high-voltage winding module;

[0015] A low-voltage winding module, comprising:

[0016] The second epoxy skeleton,

[0017] A low voltage winding, which is wound on the second epoxy skeleton,

[0018] A second potting layer covers the low-voltage winding to form a potted low-voltage winding module.

[0019] In the semi-potted Litz wire shielded high-voltage and high-frequency transformer structure, air gaps exist between the low-voltage winding, the high-voltage winding, and the magnetic core module, and the modules can be disassembled separately.

[0020] In the semi-potted Litz wire shielded high-voltage and high-frequency transformer structure, an air duct is reserved between the magnetic core module and the adjacent low-voltage winding module.

[0021] In the semi-potted Litz wire shielded high-voltage and high-frequency transformer structure, two magnetic cores arranged up and down are fixed by a cable tie.

[0022] In the semi-potted Litz wire shielded high-voltage and high-frequency transformer structure, the Litz wire is wound parallel to the main magnetic flux direction of the magnetic core.

[0023] In the semi-potted litz wire shielded high-voltage and high-frequency transformer structure, the litz wire is wound parallel to the high-voltage winding.

[0024] In the semi-potted Litz wire shielded high-voltage and high-frequency transformer structure, the magnetic core module is formed by connecting two E-type ferrite or nanocrystalline or amorphous magnetic cores to form a ferrite or nanocrystalline or amorphous magnetic core unit.

[0025] In the semi-potted Litz wire shielded high-voltage and high-frequency transformer structure, the first potting layer and the second potting layer are both formed by potting with epoxy material.

[0026] In the semi-potted Litz wire shielded high-voltage and high-frequency transformer structure, the grounded Litz wire is open-circuited and single-ended grounded.

[0027] In the semi-potted Litz wire shielded high-voltage and high-frequency transformer structure, the voltage field strength is concentrated in the winding potting area, so that the field strength in the air area between the windings and between the windings and the magnetic core is almost zero.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention forms a modular structure by separately potting the high- and low-voltage windings and then assembling them with a magnetic core unit. An air gap electric field shield composed of grounded Litz wire is placed inside and outside the high-voltage winding. This concentrates the electric field within the high-dielectric-strength epoxy material, effectively suppressing the electric field strength in the air between the high- and low-voltage windings, as well as between the high-voltage winding and the magnetic core. This reduces the risk of partial discharge and improves insulation performance. Furthermore, a semi-transparent heat dissipation channel allows internal heat to dissipate quickly, reducing steady-state temperature rise. The modular design facilitates replacement of only the damaged module in the event of local damage, significantly improving maintenance efficiency and reducing overall weight and manufacturing costs. These technical measures collectively address key shortcomings of existing fully potted and semi-potted methods with exposed iron yokes in terms of heat dissipation, insulation, and maintenance. This solution meets the requirements of miniaturization and lightweighting. Replacing Litz wire shielding with a semi-conductive layer, or using ordinary copper wire instead of Litz wire, can also improve electric field distribution, but this may introduce additional eddy current losses. Furthermore, an excessively large semi-conductive layer area can significantly affect the transformer's magnetic coupling. The present invention effectively regulates local electric field distribution through a Litz wire shielding layer, eliminating the need to increase winding spacing, thereby simplifying insulation design and reducing the risk of partial discharge. The Litz wire shielding layer improves electric field distribution, effectively alleviating airborne partial discharge between high- and low-voltage windings, significantly enhancing overall insulation performance and operational reliability. Separate casting between the core and each winding facilitates manufacturing and processing. Furthermore, the modular design allows for replacement of the corresponding module in the event of local damage, reducing repair complexity and costs. Separate casting of each module enables serialization, meaning that high-frequency transformers can be combined, expanded, or replaced to form a series of products based on different power or application requirements. A complete air duct structure can be designed between the core and each winding, enhancing heat dissipation performance. This maintains a low temperature rise under high power density and high-frequency operating conditions, ensuring long-term stable operation of the device. The above description is merely an overview of the technical solution of the present invention. To clarify the technical approach of the present invention and enable those skilled in the art to implement it according to the description, and to further enhance the understanding of the aforementioned and other objects, features, and advantages of the present invention, the following examples illustrate specific embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Various other advantages and benefits of the present invention will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are intended only to illustrate preferred embodiments and are not to be construed as limiting the present invention. It should be understood that the drawings described below are merely examples of the present invention, and that those skilled in the art will be able to derive other drawings from these drawings without inventive effort. Throughout the drawings, identical reference numerals are used to denote identical components.

[0031] In the attached figure:

[0032] Figure 1 Schematic diagrams of the top view and side view of the modular semi-potted high-frequency transformer based on the Litz wire air gap electric field shielding solution of the present invention;

[0033] Figure 2 1 is a structural diagram of an EE-type magnetic core module that can be used in the present invention;

[0034] Figure 3 This is a schematic diagram of the electric field simulation of the core window without Litz wire shielding;

[0035] Figure 4 This is a schematic diagram of the electric field simulation of the core window where the Litz wire is tightly wound parallel to the high-voltage winding;

[0036] Figure 5 This is a schematic diagram of the electric field simulation of the core window when the Litz wire is wound parallel to the high-voltage winding, leaving 50% of the electric field shielding wire diameter;

[0037] Figures 6(a) and 6(b) are schematic diagrams of the high-voltage winding when it is not potted. Figure 6(a) shows that the grounding Litz wire is wound along the direction of the core window (i.e., parallel to the main magnetic flux direction of the core), and Figure 6(b) shows that the grounding Litz wire is wound parallel to the high-voltage winding.

[0038] Figure 7 This is a schematic diagram of the low-voltage winding before and after potting;

[0039] Figure 8 This is the electric field distribution diagram of the core window after applying the Litz wire winding shielding layer;

[0040] Figure 9 This is a cross-sectional view of the high-frequency electric field after applying the Litz wire winding shield;

[0041] Figure 10 This is the electric field distribution diagram of the core window without applying the Litz wire shielding layer.

[0042] The present invention will be further explained below with reference to the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0043] Specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0044] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the invention. The scope of protection of the present invention shall be as defined in the attached claims.

[0045] To facilitate understanding of the embodiments of the present invention, several specific embodiments will be further explained below with reference to the accompanying drawings. However, the accompanying drawings do not limit the embodiments of the present invention.

[0046] For better understanding, Figures 1 to 10 As shown, a semi-potted grounded Litz wire shielded high-voltage high-frequency transformer structure includes:

[0047] The core module can be a core unit composed of two E-shaped ferrite cores connected together, or it can be a U-shaped, nanocrystalline, and other shapes and materials.

[0048] A high-voltage winding module is wound around the magnetic core module. The high-voltage winding module includes:

[0049] The first epoxy skeleton,

[0050] The high voltage winding is wound on the first epoxy frame via Litz wire,

[0051] The shielding layer is made of grounded Litz wire, and the shielding layer forms a complete coverage between the high-voltage winding and the iron yoke, and between the high-voltage winding and the low-voltage winding. The first potting layer covers the high-voltage winding and the shielding layer to form a potted high-voltage winding module;

[0052] A low-voltage winding module surrounds the high-voltage winding module, and the low-voltage winding module includes:

[0053] The second epoxy skeleton,

[0054] A low voltage winding, which is wound on the second epoxy skeleton,

[0055] A second potting layer covers the low-voltage winding to form a potted low-voltage winding module.

[0056] In the semi-potted Litz wire shielded high-voltage and high-frequency transformer structure, air gaps exist between the low-voltage winding, the high-voltage winding, and the magnetic core module, and the modules can be disassembled separately.

[0057] In the semi-potted Litz wire shielded high-voltage and high-frequency transformer structure, an air duct is reserved between the magnetic core module and the adjacent low-voltage winding module.

[0058] In the semi-potted Litz wire shielded high-voltage and high-frequency transformer structure, two magnetic cores arranged up and down are fixed by a cable tie.

[0059] In the semi-potted Litz wire shielded high-voltage and high-frequency transformer structure, the Litz wire is wound parallel to the main magnetic flux direction of the magnetic core.

[0060] In the semi-potted litz wire shielded high-voltage and high-frequency transformer structure, the litz wire is wound parallel to the high-voltage winding.

[0061] In the semi-potted Litz wire shielded high-voltage and high-frequency transformer structure, the magnetic core module is formed by connecting two E-type ferrite or nanocrystalline or amorphous magnetic cores to form a ferrite or nanocrystalline or amorphous magnetic core unit.

[0062] In the semi-potted Litz wire shielded high-voltage and high-frequency transformer structure, the first potting layer and the second potting layer are both formed by potting with epoxy material.

[0063] In the semi-potted Litz wire shielded high-voltage and high-frequency transformer structure, the grounded Litz wire is open-circuited and single-ended grounded.

[0064] In the semi-potted Litz wire shielded high-voltage and high-frequency transformer structure, the voltage field strength is concentrated in the potting area of ​​the winding, so that the field strength in the air area between the windings and between the windings and the magnetic core is close to zero. In one embodiment, by providing a Litz wire shielding layer on the inside and outside of the high-voltage winding, including a shielding structure for the side yoke and the upper and lower iron yokes, effective suppression of local high electric field areas is achieved, so that the electric field strength in the epoxy potting area is controlled within a safe range, thereby significantly reducing the risk of local discharge and improving the overall insulation performance and reliability. With a modular design, when a local part of the transformer (such as the high-voltage winding, the magnetic core unit or the low-voltage winding) fails or is processed incorrectly, only the damaged module needs to be replaced, without replacing the entire system. This design greatly reduces maintenance costs, downtime and product yield, and improves the maintenance convenience and reliability of the system.

[0065] In one embodiment, the present invention is based on a modular semi-potted high-frequency transformer with a Litz wire air gap electric field shielding solution, such as Figure 1 As shown, it includes low-voltage winding, high-voltage winding, magnetic core, and reserved ventilation ducts, such as Figure 1 As shown, it also includes the filling structure and insulation treatment structure of the winding.

[0066] The magnetic core module is a key component of the high-frequency transformer structure of the present invention, and its design is directly related to the magnetic flux transfer and thermal performance of the transformer.

[0067] The core module is a key component in high-frequency transformers. Its design directly affects magnetic flux transfer, loss control, and heat dissipation performance. Specifically, the core module has the following main features:

[0068] A core module typically consists of two E-shaped ferrite (or nanocrystalline, or amorphous) cores joined together to form a single ferrite (or nanocrystalline, or amorphous) core unit. Because larger cores are difficult to process, multiple U-shaped core units with equal combined flux areas can be used in parallel to overcome this process challenge. The E-shaped cores, arranged one above the other, are secured with cable ties to minimize the air gap between the cores, achieving higher flux density and excellent magnetic circuit performance.

[0069] The core module design offers flexibility. The number and combination of core units can be adjusted based on the transformer's required capacity and core size. This not only facilitates modular maintenance and partial replacement, but also reduces overall maintenance costs and improves equipment reliability and cost-effectiveness.

[0070] Ferrite cores have low losses at 90-100°C, which helps reduce transformer energy loss and steady-state temperature control during high-frequency operation. In contrast, nanocrystalline cores, while offering higher saturation flux density and suitable for high-power density transformers, have higher heat dissipation requirements, placing stricter demands on the core module's heat dissipation design. This invention allows for the selection of cores of appropriate material, shape, and size based on varying loss and volume requirements. Figure 2 Schematic diagram of EE type magnetic core.

[0071] In this invention, the high-voltage winding module uses Litz wire as the main winding material to effectively reduce the skin effect during high-frequency operation. A shielding layer composed of fine grounded Litz wire is set around the winding to control the electric field distribution and reduce the risk of partial discharge.

[0072] The shielding layer is placed between the high-voltage winding and the magnetic core, as well as between the high-voltage winding and the low-voltage winding, to ensure effective shielding of the electric field in all areas. As shown in Figure 6(a), in the core window area, the shielding layer is primarily wound along the core window direction, that is, parallel to the main magnetic flux direction of the core. The shielding layer forms a complete coverage between the high-voltage winding and the upper and lower iron yokes and side yokes of the magnetic core, as well as between the high-voltage winding and the low-voltage winding, ensuring that the electric field is effectively shielded within the high-voltage winding area. In addition, the shielding layer can also be arranged parallel to the high-voltage winding direction, as shown in Figure 6(b), to also improve the electric field effect.

[0073] In terms of processing technology, the high-voltage winding is first evenly wound on an epoxy skeleton of the same material to ensure the stability and uniformity of the winding structure. Subsequently, the skeleton, pre-arranged with the above-mentioned shielding layer, is placed in a mold for potting. Fine Litz wire shielding layers are reserved both inside and outside the winding, especially in the core window area. By strengthening the shielding protection, it effectively suppresses magnetic field leakage and the formation of local high electric field areas, further reducing the risk of partial discharge. In addition, the Litz wire shielding layer extends in the upper and lower directions of the high-voltage winding, exceeding the range of the high-voltage winding, effectively protecting the electric field near the upper and lower iron yokes and reducing the risk of partial discharge near the upper and lower iron yokes.

[0074] The following example illustrates the improvement effect of Litz wire on the electric field. For the high-frequency transformer shown below, epoxy potting is used, and Litz wire shielding is not used. There is a 0.5mm air gap between the winding and the core after potting. The electric field simulation results are as follows: Figure 3 As shown in the figure, it can be found that the field strength near the side yoke and the upper and lower iron yokes of the high-voltage winding is relatively large, exceeding 3kV / mm, and air discharge occurs.

[0075] The electric field shielding layer is constructed by using open-circuited and single-end grounded Litz wires. Considering the close winding of the Litz wires, the electric field simulation results are as follows: Figure 4 As shown in the figure, it can be found that the maximum electric field strength in the air region of the upper and lower iron yokes decays from 2.5kV / mm to 0.9kV / mm, while the electric field strength in the side yoke decays from 8kV / mm to 0.

[0076] The Litz wires are not tightly wound (leaving 50% of the diameter of the electric field shielding wire), which also has a good improvement effect on the electric field. The electric field simulation results are as follows: Figure 5 As shown, it can be seen that the maximum electric field strength of the side yoke is reduced from 8kV / mm to 0.04kV / mm; the maximum electric field strength of the upper and lower iron yokes is attenuated from 2.5kV / mm to 0.18kV / mm, which is still lower than the breakdown electric field strength of air of 3kV / mm.

[0077] Through this design and manufacturing process, the high-voltage winding module not only reduces the skin effect and losses, but also improves heat dissipation conditions while ensuring high insulation performance. This meets the various technical requirements of high-power density and high-frequency transformers in practical applications, while also facilitating modular maintenance and partial replacement. The structure of the high-voltage winding is shown in Figures 6(a) and 6(b), which respectively show the winding method of the grounded Litz wire along the direction of the core window (i.e., parallel to the main magnetic flux direction of the core) and parallel to the high-voltage winding.

[0078] The low-voltage winding module adopts the same integral potting process as the high-voltage winding. The winding can be directly wound on the epoxy skeleton and potted as a whole, ensuring the mechanical stability and overall insulation of the winding. Compared with the high-voltage winding, the low-voltage winding module does not have a fine Litz wire shielding layer, which is simpler in design and has lower losses. At the same time, a certain air gap can be designed between the low-voltage winding and the high-voltage winding to form an air duct from bottom to top, which is conducive to the rapid dissipation of internal heat, thereby effectively improving the heat dissipation performance. This design not only meets the lower voltage level and heat load requirements of the low-voltage side, but also ensures the insulation safety and stable operation of the overall structure. The low-voltage winding structure is as follows Figure 7 shown.

[0079] Using a 70kW / 70kVA prototype as an example, this study employed finite element simulation to simulate the electric field distribution under a 13kV partial discharge withstand voltage condition, with the transformer's high-voltage winding shorted to 13kV and the low-voltage winding shorted to ground. The simulation compared two different designs: one with a Litz wire shield in the high-voltage winding module and one without.

[0080] Figure 8 The electric field distribution in the core window plane after applying the Litz wire winding shield is shown. It can be seen that all areas with electric field strengths greater than 3kV / mm (the air breakdown field strength) are located inside the high-voltage winding (i.e., within the epoxy potting area), while the electric field strengths in other areas are lower than the air breakdown field strength. This clearly demonstrates that the Litz wire shield significantly optimizes the electric field distribution. By adjusting the distance between the Litz wire shield and the high-voltage winding, the electric field strength inside the epoxy can be further controlled, stabilizing it within the epoxy material's tolerance range. Figure 9 This is a cross-sectional view of the high-frequency variable electric field after applying the Litz wire winding shielding layer. It can be seen that the electric field intensity changes more dramatically near the Litz wire, and all high-field areas exceeding 3kV / mm are located in the epoxy potting area.

[0081] Figure 10The electric field distribution diagram of the core window without the litz wire shield is shown. It can be clearly seen from the figure that the electric field strength in the air gap area between the high-voltage winding and the iron yoke and between the high-low winding and the low-voltage winding exceeds 3kV / mm (i.e., the air breakdown field strength), indicating that the air in these areas is very prone to partial discharge or breakdown. Figure 10 and Figure 8 By comparison, the excellent performance of the Litz wire shielding layer in improving the electric field distribution and reducing the risk of local high electric fields can be fully demonstrated.

[0082] In one embodiment, this structure utilizes a Litz wire air-gap electric field shielding solution. By winding Litz wire into a shielding layer, the electric field between the high-voltage winding and the core window, as well as between the high- and low-voltage windings, is concentrated within the potting area. The Litz wire winding arrangement can be flexibly arranged based on the core's main magnetic flux density and actual design requirements. It is primarily wound along the core window, but can also be arranged parallel to the conductor. In this structure, the core module can be constructed from two E-shaped ferrite cores joined together, or it can utilize cores of various shapes and materials, such as U-shaped and nanocrystalline, to accommodate different power densities and application scenarios. The high-voltage winding is wound with Litz wire (or other conductor) on a first epoxy bobbin and equipped with a grounded Litz wire shield. This shield can be flexibly arranged (e.g., parallel to the winding) based on the core's main magnetic flux density and actual design requirements, thereby providing stable electric field isolation between the high-voltage winding and the core window, as well as between the high- and low-voltage windings. The low-voltage winding is wound on a second epoxy bobbin and covered by a second potting layer. This structure not only fully leverages the advantages of the grounded litz wire shielding solution in reducing the risk of partial discharge and improving thermal management, but also achieves flexible combination of various parts (i.e. serialization) through modular design, facilitating mass production, multi-specification applications and subsequent maintenance and upgrades.

[0083] Core modules can be constructed from two E-shaped ferrite cores joined together, or they can be made from a variety of shapes and materials, including U-shaped and nanocrystalline. Core modules are key components in high-frequency transformers, and their design directly impacts magnetic flux transfer, loss control, and heat dissipation. This design flexibility not only helps overcome processing challenges but also allows the number and combination of core units to be adjusted to meet specific application requirements, optimizing magnetic flux density and thermal management.

[0084] The high-voltage winding module consists of a first epoxy skeleton, a high-voltage winding (wound around it with Litz wire), a shielding layer (made of grounded Litz wire), and a first potting layer. The Litz wire design effectively reduces the skin effect during high-frequency operation, and the shielding layer further reduces the risk of partial discharge. Furthermore, the potting layer not only protects the winding from physical damage but also improves the stability and insulation of the overall structure.

[0085] The low-voltage winding module consists of a second epoxy carcass, a low-voltage winding (wound around it), and a second potting layer. This design simplifies manufacturing while ensuring mechanical stability and overall insulation. Compared to the high-voltage winding, the low-voltage winding module does not utilize a fine Litz wire shield, reducing complexity and cost while maintaining the necessary electrical isolation and heat dissipation efficiency.

[0086] Air gaps and air ducts are designed between the low-voltage winding, high-voltage winding, and core module, allowing for independent removal. Air ducts are also provided between the core module and the adjacent low-voltage winding module. This design promotes efficient internal heat dissipation, improves heat dissipation, and facilitates maintenance and partial replacement, reducing downtime and maintenance costs.

[0087] The Litz wire shield utilizes open-circuited, single-end grounded Litz wire to create an electric field shield, effectively suppressing magnetic field leakage and the formation of localized high electric field areas, reducing the risk of partial discharge. This shield significantly optimizes the electric field distribution, significantly reducing the maximum field strength in the air region, ensuring higher safety standards and reliability.

[0088] The modular design allows for partial transformer failure or manufacturing errors, requiring only the damaged module to be replaced, rather than the entire system. This significantly improves system maintenance convenience and cost-effectiveness, while also enhancing equipment reliability and durability.

[0089] A core module typically consists of two E-shaped ferrite (or nanocrystalline, or amorphous) cores joined together to form a single ferrite (or nanocrystalline, or amorphous) core unit. Because larger cores are difficult to process, multiple U-shaped core units with equal combined flux areas can be used in parallel to overcome this process challenge. The E-shaped cores, arranged one above the other, are secured with cable ties to minimize the air gap between the cores, achieving higher flux density and excellent magnetic circuit performance.

[0090] This design flexibility not only helps overcome processing challenges, but also allows the number and combination of core units to be adjusted according to different application requirements, thereby optimizing magnetic flux density and thermal management.

[0091] The high-voltage winding module uses Litz wire as the primary winding material to effectively reduce the skin effect during high-frequency operation. A shield layer composed of fine grounded Litz wire is placed around the winding to control the electric field distribution and reduce the risk of partial discharge.

[0092] The Litz wire design effectively reduces the skin effect during high-frequency operation and further reduces the risk of partial discharge through the shielding layer.

[0093] The low-voltage winding module utilizes the same integral potting process as the high-voltage winding. The windings are directly wound and uniformly wound onto the epoxy frame and then potted, ensuring mechanical stability and overall insulation. Compared to the high-voltage winding, the low-voltage winding module does not utilize a fine Litz wire shield, resulting in a simpler design and lower losses. Furthermore, a defined air gap can be designed between the low-voltage and high-voltage windings, creating an upward airflow path that facilitates the rapid dissipation of internal heat and effectively improves heat dissipation.

[0094] The low-voltage winding design simplifies the manufacturing process while ensuring mechanical stability and overall insulation. This design promotes efficient internal heat dissipation, improves heat dissipation, and facilitates maintenance and partial replacement, reducing downtime and maintenance costs.

[0095] The basic principles of the present application have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, and effects mentioned in this application are merely illustrative and not restrictive, and it should not be assumed that these advantages, strengths, and effects are required of each embodiment of this application. In addition, the specific details disclosed above are merely illustrative and facilitating understanding, and are not restrictive. The above details do not limit this application to necessarily being implemented using the above specific details.

[0096] The above description has been provided for the purpose of illustration and description. Furthermore, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A semi-potted Litz wire shielded high-voltage and high-frequency transformer structure, characterized in that: These include, Magnetic core module; A high-voltage winding module, comprising: The first epoxy skeleton, High voltage winding, which is wound on the first epoxy frame via Litz wire, The shielding layer is made of grounded Litz wire, and the shielding layer forms a complete coverage between the high-voltage winding and the iron yoke, and between the high-voltage winding and the low-voltage winding. a first potting layer covering the high-voltage winding and the shielding layer to form a potted high-voltage winding module; A low-voltage winding module, comprising: The second epoxy skeleton, A low voltage winding, which is wound on the second epoxy skeleton, A second potting layer covers the low-voltage winding to form a potted low-voltage winding module.

2. The semi-potted Litz wire shielded high-voltage and high-frequency transformer structure according to claim 1, characterized in that: Preferably, there is an air gap between the low-voltage winding, the high-voltage winding, and the magnetic core module, and they can be disassembled separately.

3. The semi-potted Litz wire shielded high-voltage and high-frequency transformer structure according to claim 1, characterized in that: An air duct is reserved between the magnetic core module and the adjacent low-voltage winding module.

4. The semi-potted Litz wire shielded high-voltage and high-frequency transformer structure according to claim 1, characterized in that: The two magnetic cores arranged one above the other are fixed with cable ties.

5. The semi-potted Litz wire shielded high-voltage and high-frequency transformer structure according to claim 1, characterized in that: The Litz wire is wound parallel to the main flux direction of the core.

6. The semi-potted litz wire shielded high-voltage and high-frequency transformer structure as claimed in claim 1, wherein the litz wire is wound parallel to the high-voltage winding.

7. The semi-potted Litz wire shielded high-voltage and high-frequency transformer structure according to claim 1, characterized in that: The magnetic core module is formed by connecting two E-type ferrite or nanocrystalline or amorphous magnetic cores to form a ferrite or nanocrystalline or amorphous magnetic core unit.

8. The semi-potted Litz wire shielded high-voltage and high-frequency transformer structure according to claim 1, characterized in that: The first encapsulation layer and the second encapsulation layer are both formed by encapsulating with epoxy material.

9. The semi-potted Litz wire shielded high-voltage and high-frequency transformer structure according to claim 1, characterized in that: The grounding litz wire is open-circuited and grounded at one end.

10. The semi-potted Litz wire shielded high-voltage and high-frequency transformer structure according to claim 1, characterized in that: The voltage field strength is concentrated in the winding potting area, so that the field strength in the air area between the windings and between the windings and the magnetic core is close to zero.

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