Non-potted medium voltage insulation high frequency isolation transformer

Abstract

This invention provides a non-potted medium-voltage insulated high-frequency isolation transformer, belonging to the technical field of power electronics and high-frequency magnetic components. The invention includes a first and second magnetic core arranged vertically opposite each other at their open ends, a PCB insulating board horizontally placed between the two magnetic cores, windings respectively arranged on both sides of the PCB insulating board, a semi-conductive coating applied to both surfaces of the PCB insulating board, and a conductive shielding layer embedded within the PCB insulating board. The PCB insulating board simultaneously provides electrical insulation between the two magnetic cores and primary insulation between the primary and secondary windings, replacing the traditional integral potting process. The semi-conductive coating homogenizes the electric field on the surface of the PCB insulating board to suppress corona partial discharge, and the embedded conductive shielding layer confines the high-field region at the three-state point within the PCB insulating board to suppress air partial discharge at the three-state point. The transformer of this invention has a compact structure, good heat dissipation, and simplified manufacturing process, making it particularly suitable for medium-voltage high-power power electronic equipment such as solid-state transformers.

Description

Technical Field

[0001] This invention relates to a non-potted medium-voltage insulated high-frequency isolation transformer, belonging to the field of power electronics and high-frequency magnetic components technology. Background Technology

[0002] As power electronic equipment develops towards higher frequencies, higher power densities, and medium-voltage levels, solid-state transformers are increasingly widely used in medium-voltage power distribution, new energy grid connection, and electrified traction. Their core component, the medium-voltage insulated high-frequency isolation transformer, undertakes two major functions: high-frequency power transfer and electrical isolation between the primary and secondary sides. Because it operates at voltages of several kilovolts to tens of kilovolts and frequencies of several kilohertz to tens of kilohertz, the design of the primary and secondary side insulation is a core challenge in the overall design.

[0003] In existing technologies, the most widely used insulation solution for medium-voltage, high-frequency transformers is the integral insulation potting process—after the transformer core and windings are assembled, the entire transformer is encapsulated using insulating media such as epoxy resin and silicone rubber, relying on the cured potting material as the primary and secondary insulation medium. However, this solution has the following insurmountable technical problems under medium-voltage, high-frequency conditions:

[0004] First, air bubbles inside the potting compound can cause corona partial discharge. Large potting compounds are difficult to completely eliminate air bubbles during the curing process, and curing shrinkage can also create new microcavities. These air bubbles become sources of partial discharge under medium-voltage electric fields, gradually degrading the insulation material and eventually leading to breakdown over long-term operation.

[0005] Second, partial discharge in air at the three-state point. Near the "three-state point" formed by the interface of the conductor, potting material, and air, the electric field is highly distorted and concentrated, and partial discharge is very likely to occur on the air side of the three-state point.

[0006] Third, heat dissipation is difficult. The integral potting tightly encapsulates the magnetic core and windings, and the heat generated by losses can only rely on the potting material with low thermal conductivity, resulting in high thermal resistance and limiting further improvement in power density.

[0007] To address the aforementioned issues, existing technologies have proposed improvements such as adding a voltage-equalizing shielding layer inside the potting compound or potting only the medium-voltage winding. However, these solutions do not break free from the potting framework, and fundamental problems such as bubble partial discharge and heat dissipation remain. In summary, the industry urgently needs a new type of medium-voltage insulated high-frequency isolation transformer structure that can eliminate the need for overall potting processes and simultaneously solve multiple problems such as bubble partial discharge, three-state point partial discharge, and heat dissipation difficulties. Summary of the Invention

[0008] The purpose of this invention is to solve the technical problems existing in medium-voltage high-frequency transformers using the traditional integral potting method, such as partial discharge of air bubbles inside the potting, partial discharge of air at the three-state point, and difficulty in heat dissipation. In order to provide a non-potting medium-voltage insulated high-frequency isolation transformer, which has a compact structure, excellent insulation performance, good heat dissipation effect, and simplified manufacturing process.

[0009] The objective of this invention is achieved through the following technical solution:

[0010] A non-potted medium-voltage insulated high-frequency isolation transformer includes: a first magnetic core, a second magnetic core, a first winding, a second winding, and a first PCB insulation board;

[0011] The first magnetic core and the second magnetic core are positioned opposite each other with a first PCB insulating plate horizontally positioned between them. A first winding is disposed on the surface of the first PCB insulating plate facing the first magnetic core, and the first winding is magnetically coupled to the first magnetic core, forming the primary side of the transformer. A second winding is disposed on the surface of the first PCB insulating plate facing the second magnetic core, and the second winding is magnetically coupled to the second magnetic core, and the second winding is positioned opposite to the first winding, forming the secondary side of the transformer. The first PCB insulating plate serves as the electrical insulation medium between the primary and secondary windings of the transformer, as well as between the first and second magnetic cores. The first magnetic core, the second magnetic core, the first winding, and the second winding are all directly exposed to the air environment.

[0012] Preferably, the two opposite surfaces of the first PCB insulating board are coated with a semi-conductive coating; the coating range of the semi-conductive coating at least completely covers the projection areas of the first magnetic core, the first winding, the second magnetic core, and the second winding on the first PCB insulating board.

[0013] Preferably, an embedded conductive shielding layer is provided between the internal multilayer dielectric layers of the first PCB insulating board; the embedded conductive shielding layer is used to transfer and confine the high field strength region at the three-state point formed by the first winding, the second winding, the first PCB insulating board and the surrounding air to the internal dielectric of the first PCB insulating board, thereby suppressing partial discharge in the air at the three-state point.

[0014] Preferably, the embedded conductive shielding layer includes multiple conductive sheets stacked along the thickness direction of the first PCB insulating board, each conductive sheet being located at a different depth of the internal dielectric of the first PCB insulating board, and adjacent conductive sheets being separated from each other by the internal dielectric layer of the first PCB insulating board.

[0015] Several layers of conductive sheets are arranged alternately with adjacent lower conductive sheets along the length of the first PCB insulating board to disperse and confine the high field strength region at the three-state point within the internal medium of the first PCB insulating board.

[0016] Preferably, the portion of the first PCB insulating board extending outward along the periphery of the board surface is the surface extension portion.

[0017] Preferably, a blind groove is formed on at least one surface of the first PCB insulating board, and the blind groove is arranged on the surface extension.

[0018] Preferably, the blind slots are arranged in a continuous closed ring or in a segmented staggered arrangement.

[0019] Preferably, the size of the non-magnetic gap in the magnetic circuit between the first magnetic core and the second magnetic core is equal to the thickness of the first PCB insulating board.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] 1. Eliminate partial discharge caused by air bubbles inside the potting compound. This invention completely abandons the traditional integral potting process and adopts an industrially produced, quality-controlled, dense, and bubble-free PCB insulating board that simultaneously undertakes the electrical insulation between the two magnetic cores and the main insulation between the primary and secondary windings. This eliminates the air bubble defects that are difficult to avoid during the curing process of the potting compound, thus preventing corona partial discharge caused by potting bubbles from the source.

[0022] 2. Effectively suppresses partial discharge at the three-state point. On one hand, this invention coats the surface of the PCB insulating board with a semi-conductive coating to homogenize the electric field on the surface of the insulating board and suppress partial discharge in the air on the PCB surface. On the other hand, this invention sets an embedded conductive shielding layer inside the PCB insulating board, transferring the high field strength region of the three-state point that was originally exposed to the air and confining it inside the solid dielectric of the PCB board, fundamentally avoiding the air-side partial discharge path at the three-state point. The synergistic effect of these two methods significantly improves the partial discharge withstand capability of the transformer under medium-voltage, high-frequency conditions.

[0023] 3. Significantly improved heat dissipation performance. Since the magnetic core and windings are directly exposed to the air, the heat generated by the iron loss of the magnetic core and the copper loss of the windings can be dissipated directly to the surrounding air through natural convection or forced air cooling, significantly reducing thermal resistance. Under the same temperature rise, it can withstand greater losses and power, which is beneficial to improving the power density of the transformer.

[0024] In summary, this invention achieves comprehensive improvements to existing medium-voltage high-frequency isolation transformers from multiple dimensions, including insulation structure, heat dissipation method, assembly process, and electromagnetic parameter adjustment, resulting in significant technical benefits. The non-potted medium-voltage insulated high-frequency isolation transformer provided by this invention has the advantages of compact structure, good heat dissipation, and simplified manufacturing process, making it particularly suitable for medium-voltage high-power power electronic equipment such as solid-state transformers. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the longitudinal cross-sectional structure along the winding axis after the assembly of the non-potted medium-voltage insulated high-frequency isolation transformer provided in an embodiment of the present invention.

[0026] Figure 2 This is a three-dimensional exploded structural diagram of a non-potted medium-voltage insulated high-frequency isolation transformer provided in an embodiment of the present invention.

[0027] Figure 3 This is a schematic diagram of the longitudinal cross-sectional structure of the PCB insulation board along its thickness direction in the non-potted medium-voltage insulated high-frequency isolation transformer provided in an embodiment of the present invention.

[0028] Figure 4 This is a top view of the blind slots on the PCB insulation board provided in an embodiment of the present invention, which adopt a closed multi-ring arrangement.

[0029] Figure 5 This is a top view of the PCB insulation board with a segmented staggered arrangement of blind slots provided in an embodiment of the present invention.

[0030] Figure 6 This is a longitudinal cross-sectional structural diagram of an embodiment of the non-potted medium-voltage high-frequency isolation transformer provided in this invention, in which both the first and second magnetic cores adopt U-shaped magnetic cores.

[0031] Figure 7 The diagram shows a longitudinal cross-sectional view of the non-encapsulated medium-voltage high-frequency isolation transformer provided in this embodiment of the invention, which uses a multi-PCB insulation board arrangement to achieve a three-port structure of low-voltage-medium-voltage-low-voltage.

[0032] In the figure, the reference numerals are as follows: 10 is the first magnetic core, 20 is the second magnetic core, 30 is the first winding, 40 is the second winding, 50 is the third magnetic core, 60 is the third winding, 100 is the first PCB insulating board, 110 is the semi-conductive coating, 120 is the embedded conductive shielding layer, 121 is the conductive sheet, 130 is the surface extension, 140 is the blind slot, 141 is the slot sidewall, 142 is the slot bottom, and 200 is the second PCB insulating board. Detailed Implementation

[0033] The following is a detailed description of the non-potted medium-voltage insulated high-frequency isolation transformer and the solid-state transformer including the present invention, with reference to the accompanying drawings. It should be noted that the following description of the embodiments of the present invention with reference to the accompanying drawings is merely exemplary and not intended to limit the present invention; any improvements, modifications, equivalent substitutions, or combinations made by those skilled in the art without departing from the concept of the present invention should fall within the protection scope of the present invention.

[0034] Furthermore, the directional terms such as "upper," "lower," "horizontal," "vertical," "axial," and "normal direction" used in this specification are descriptions based on the relative positional relationships shown in the accompanying drawings, and are only used to facilitate the explanation of the relative relationships between the various components of the present invention. They should not be construed as limitations on the actual installation orientation of the present invention. In different engineering practices, the transformer described in this invention can be arranged in any orientation according to specific installation conditions.

[0035] The shapes, proportions, and dimensions of the components shown in the accompanying drawings are merely illustrative and are not drawn to actual scale, nor should they be construed as limiting the invention.

[0036] Example 1:

[0037] This embodiment provides a typical implementation of a non-potted medium-voltage insulated high-frequency isolation transformer, as follows:

[0038] like Figure 1 and Figure 2 As shown, the non-potted medium-voltage insulated high-frequency isolation transformer has a stacked symmetrical structure along the vertical direction, comprising, from top to bottom, a first magnetic core 10, a first winding 30, a first PCB insulating board 100, a second winding 40, and a second magnetic core 20. The first PCB insulating board 100 is horizontally arranged, and the first magnetic core 10 and the second magnetic core 20 face each other vertically but are separated from each other by the first PCB insulating board 100 and do not directly contact each other; the first winding 30 and the second winding 40 are located on both sides of the first PCB insulating board 100 and are arranged opposite each other with a gap between them. The non-potted medium-voltage insulated high-frequency isolation transformer does not have any overall potting structure covering the magnetic core and windings. The first magnetic core 10, the second magnetic core 20, the first winding 30, and the second winding 40 are all directly exposed to the air environment without potting.

[0039] The first magnetic core 10 and the second magnetic core 20 are made of high-frequency, low-loss soft magnetic materials such as ferrite and nanocrystals. Figure 1As shown, the two cores are joined together vertically to form a closed magnetic circuit around the winding, with their end faces tightly abutting the surface of the first PCB insulating board 100. The shapes of the first magnetic core 10 and the second magnetic core 20 are not limited to one type; they can be any shape of magnetic core, such as U-shaped, E-shaped, I-shaped, C-shaped, can-shaped, or toroidal. The first magnetic core 10 and the second magnetic core 20 have the same shape. Since the first magnetic core 10 and the second magnetic core 20 are separated from each other by the first PCB insulating board 100, the thickness direction of the first PCB insulating board 100 naturally forms a non-magnetic gap in the magnetic circuit. The transformer excitation inductance can be flexibly adjusted by selecting different thicknesses of the first PCB insulating board 100, which is particularly suitable for LLC and dual active bridge (DAB) converter topologies.

[0040] The first PCB insulating board 100 adopts a multilayer PCB structure, and the substrate material can be selected from epoxy resin composite materials, polyimide, ceramic matrix composite materials, etc. It simultaneously performs two insulation functions: serving as the main insulating medium between the primary and secondary windings (replacing traditional potting materials), and also as the electrical insulating medium between the first magnetic core 10 and the second magnetic core 20 (the two magnetic cores are at different potentials due to their respective coupling with the primary and secondary windings). The first PCB insulating board 100 employs two stacking mechanisms to optimize the surface creepage distance: one is to extend outward along the board surface direction beyond the outer contour boundary of the two magnetic cores to form a surface creepage extension 130 (e.g., ...). Figure 1 As shown, the creepage distance is extended laterally along the board surface to increase the creepage distance between the primary and secondary sides of the transformer; secondly, a blind slot 140 is formed on at least one surface. The blind slot 140 is a recessed structure that opens onto the PCB board surface but does not penetrate its thickness direction. Through its slot sidewall 141 and slot bottom 142, the creepage path between the primary and secondary sides of the transformer is increased, forming a three-dimensional extension (along the board thickness direction), and shortening the outward extension dimension of the first PCB insulating board 100. The two mechanisms are complementary and can be used simultaneously, significantly increasing the effective creepage distance without increasing the planar size of the PCB board.

[0041] The first winding 30 and the second winding 40 are respectively arranged on both sides of the first PCB insulating board 100, and are wound around the corresponding magnetic cores. For example... Figure 1 As shown, each winding presents two sets of symmetrically distributed conductor sections in the longitudinal section (corresponding to both sides of the magnetic circuit central axis respectively), and each turn of the same winding is stacked along the thickness direction of the first PCB insulating board 100. Figure 2The geometry of the winding is illustrated. The winding can be formed by winding flat copper strip, Litz wire, or copper foil around the central axis of the magnetic circuit. The voltage ratio is set by the turns ratio of the two windings; by adjusting the distance between the first winding 30 and the second winding 40 along the normal direction of the first PCB insulating board 100 and the range of their unfolding within the plane of the first PCB insulating board 100, and in conjunction with the adjustment of the air gap of the magnetic circuit by the PCB board thickness, the magnetizing inductance and leakage inductance of the non-potted medium-voltage insulated high-frequency isolation transformer can be precisely controlled to achieve parameter matching.

[0042] like Figure 1 As shown, a semiconductive coating 110 is coated on the surface of the first PCB insulating board 100. The semiconductive coating 110 is used to homogenize the electric field distribution on the surface of the first PCB insulating board 100 and suppress corona partial discharge in the air between the primary and secondary windings and the first PCB insulating board 100. Its coating range at least completely covers the projection areas of the first magnetic core 10, the first winding 30, the second magnetic core 20, and the second winding 40 on the first PCB insulating board 100. The material of the semiconductive coating 110 can be a composite coating doped with graphite, carbon black, or conductive polymer, with an appropriate volume resistivity—which can both homogenize the electric field on the PCB board surface, release the high field strength at sharp corners and edges, and reduce eddy current losses, effectively suppressing corona partial discharge on the air side near the three-state point.

[0043] like Figure 1 As shown, the embedded conductive shielding layer 120 is composed of multiple layers of conductive sheets 121 stacked along the thickness direction of the first PCB insulating board 100. Each layer of conductive sheets 121 is located at a different depth of the internal dielectric layer of the first PCB insulating board 100, and adjacent conductive sheets 121 are separated from each other by the internal dielectric layer of the first PCB insulating board 100. The several layers of conductive sheets 121 and the adjacent lower conductive sheets 121 are arranged alternately along the length direction of the first PCB insulating board 100 to disperse and confine the high field strength region at the three-state point within the internal dielectric layer of the first PCB insulating board 100. An embedded conductive shielding layer 120 is arranged in the edge region of the first winding 30 and the second winding 40 along the board surface direction, that is, in the location where the primary and secondary windings, together with the PCB insulating board and air, form a tri-state point where high electric field strength is easily concentrated. Its working principle is as follows: since the edges of each conductive sheet 121 are staggered along the board surface direction, the PCB internal dielectric between adjacent conductive sheets 121 forms a capacitor connected in series along the thickness direction. This causes the high electric field strength originally concentrated at the tri-state point on the air side of the winding edge to be gradually and smoothly transitioned along the stepped shielding structure, and then transferred and constrained in the internal solid dielectric of the first PCB insulating board 100. Since the internal dielectric of the PCB is dense and bubble-free and has a dielectric constant higher than that of air, the partial discharge path on the air side near the tri-state point is effectively cut off, thereby suppressing partial discharge in the air at the tri-state point.

[0044] It should be noted that this embodiment only provides a conceptual description of the function, location, and working principle of the embedded conductive shielding layer 120, and its specific geometry, coverage area, and connection method with the winding potential are not considered as limitations on the scope of protection of this invention.

[0045] The transformer adopts a separate assembly structure: the first magnetic core 10, the second magnetic core 20, the first PCB insulating board 100 (including its surface semi-conductive coating 110, embedded conductive shielding layer 120, surface extension 130, and blind slot 140), the first winding 30, and the second winding 40 are independently processed and then mechanically assembled in sequence, without the need for an overall potting process. The magnetic cores and windings are directly exposed to the air, and the iron losses of the magnetic cores and the copper losses of the windings generated during operation can be directly dissipated through natural convection or forced air cooling. The heat dissipation path is short, the thermal resistance is low, and the temperature rise is small, which is beneficial to improving the power density of the transformer.

[0046] Example 2:

[0047] This embodiment, based on Embodiment 1, further explains the specific implementation method for optimizing the creepage distance along the surface, focusing on the structural arrangement of the surface extension 130 and the blind slot 140 on the first PCB insulating board 100. The structures of other transformer components in this embodiment are the same as in Embodiment 1, and will not be repeated below.

[0048] Figure 3 This schematically illustrates the longitudinal cross-sectional structure of the first PCB insulating board 100 along its thickness direction in this embodiment (only the PCB board and its surface / internal functional layers are shown; the magnetic core and windings are not shown). The functional layers and functional areas on the first PCB insulating board 100 are clearly spatially defined:

[0049] The central region (corresponding to the magnetic core and winding coverage area) is provided with a semi-conductive coating 110 (coated on both sides of the PCB board) and an embedded conductive shielding layer 120 (intercalated in the dielectric layer inside the PCB board), which undertakes the functions of electric field homogenization and three-state point electric field transfer; the outer edge region (the part that extends beyond the outline of the conductive coating) is used as a surface creepage extension 130, and several blind slots 140 are formed on its surface (blind slots include slot sidewalls 141 and slot bottoms 142), which undertake the function of optimizing surface creepage distance.

[0050] Figure 4 This diagram illustrates a top view of the blind slot 140 arrangement on the first PCB insulating board 100 in this embodiment. It should be noted that the white area in the diagram represents the location of the blind slot 140 (i.e., the slotted portion of the PCB board), the green area represents the unslotted surface of the PCB board, and the central dark rectangular area represents the coverage area of ​​the magnetic core and windings on the PCB board (i.e., the coverage area of ​​the semi-conductive coating 110).

[0051] In this embodiment, the blind slots 140 are arranged in a continuous closed ring geometry around the central high field strength region. Each blind slot forms a continuous closed rectangular ring (or a circular ring, elliptical ring, or other closed ring) on ​​the surface of the first PCB insulating board 100. Multiple blind slots are arranged concentrically nested along the PCB board surface. Each annular blind slot forms a complete "slot wall-slot bottom-slot wall" three-dimensional blockage of the surface creepage path. The shortest surface creepage path between the primary and secondary sides must cross all blind slots in sequence to complete the conduction. This arrangement is simple in structure, easy to manufacture, and the reinforcement effect in each creepage direction is uniform.

[0052] See Figure 5 (The meaning of the colors in the picture and) Figure 4 (Same as above) In this embodiment, the blind slot 140 adopts a segmented and staggered geometric shape - each blind slot is no longer a complete closed loop, but is composed of multiple segments, and the opening positions between adjacent segments are alternately staggered. Since the PCB no longer has a full circle of blind slots, the PCB structural strength can be increased.

[0053] Regardless of the method Figure 4 The closed multi-ring arrangement shown is still Figure 5 The segmented, staggered arrangement shown features simultaneous and synergistic creepage extensions 130 and blind slots 140: the former extends the creepage distance laterally along the PCB surface (determined by the outward extension dimensions of the PCB), while the latter extends the creepage distance three-dimensionally along the PCB thickness (determined by the depth and number of channels of the blind slot). By rationally designing the extension width of the extension 130 and the depth, width, number of channels, channel spacing, and geometric arrangement of the blind slots 140, the effective creepage distance between the primary and secondary sides of the transformer can be flexibly configured within a specified PCB planar size to meet the insulation requirements of different voltage levels and pollution levels.

[0054] Furthermore, Figure 4 The closed multi-ring arrangement shown is Figure 5 The segmented staggered arrangement shown is not mutually exclusive—two blind slot forms can be used simultaneously on the same first PCB insulating board 100.

[0055] Example 3:

[0056] This embodiment demonstrates two different implementations of the magnetic core shape and the number of PCB insulating boards based on Embodiment 1. The functions of each functional layer (including: semiconductive coating 110, embedded conductive shielding layer 120, surface creepage extension 130, and blind slot 140) in this embodiment are the same as in Embodiment 1.

[0057] See Figure 6In this embodiment, both the first magnetic core 10 and the second magnetic core 20 adopt a U-shaped structure: the first magnetic core 10 is a U-shaped structure with the opening facing downward and its magnetic column extending downward; the second magnetic core 20 is a U-shaped structure with the opening facing upward and its magnetic column extending upward; the end faces of the magnetic columns of the two magnetic cores are respectively in close contact with the two surfaces of the first PCB insulating board 100, but the two are separated from each other by the first PCB insulating board 100 and do not directly contact each other, thus forming a closed magnetic circuit around the first winding 30 and the second winding 40.

[0058] See Figure 7 This embodiment, based on the basic structure described in Example 1 ("two magnetic cores + one PCB board + two windings"), further adds a third magnetic core 50, a third winding 60, and a second PCB insulating board 200 (which has the same substrate material, surface semi-conductive coating 110, embedded conductive shielding layer 120, surface creepage extension 130, and blind slot 140 as the first PCB insulating board 100, etc.), thus forming a non-potted medium-voltage insulated high-frequency isolation transformer with two PCB insulating boards and three sets of magnetic cores-windings. The third magnetic core 50 is the same as the second magnetic core 20, while the thicknesses of the first PCB insulating board 100 and the second PCB insulating board 200 can be different.

[0059] The transformer, from top to bottom, includes a third magnetic core 50, a third winding 60, a second PCB insulation board 200, a first magnetic core 10, a first winding 30, a first PCB insulation board 100, a second winding 40, and a second magnetic core 20. The three sets of magnetic core-winding combinations form three independent electrical ports: the medium voltage port, which is composed of the first magnetic core 10 and the first winding 30 located in the middle of the transformer; the first low voltage port, which is composed of the third magnetic core 50 and the third winding 60 located above the transformer; and the second low voltage port, which is composed of the second magnetic core 20 and the second winding 40 located below the transformer.

[0060] The first PCB insulation board 100 provides the main insulation between the medium-voltage port and the second low-voltage port, as well as the electrical insulation between the first magnetic core 10 and the second magnetic core 20. The second PCB insulation board 200 provides the main insulation between the medium-voltage port and the first low-voltage port, as well as the electrical insulation between the first magnetic core 10 and the third magnetic core 50. Both PCB insulation boards independently perform the aforementioned insulation functions (main insulation between windings + electrical insulation between magnetic cores).

[0061] This arrangement enables simultaneous electromagnetic coupling and reliable electrical isolation between one medium-voltage port and two low-voltage ports within a single transformer structure.

[0062] Furthermore, the multi-PCB board arrangement described in this embodiment can be further extended in the vertical direction: by increasing the number of PCB insulating boards (let's say...). (block) and the corresponding number of core-winding groups (set as) (Group), which can constitute a group with Block PCB insulating board and ( A multi-port, non-potted, medium-voltage, high-frequency isolation transformer with 1 electrical port. This multi-port extended structure is essentially a vertical superposition of the "PCB board—magnetic core—winding" basic unit described in Embodiment 1, and still falls within the technical concept protected by claim 1 of this invention.

[0063] The above description is merely a preferred embodiment of the present invention. These specific embodiments are different implementations based on the overall concept of the present invention, and the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A non-potted medium-voltage insulated high-frequency isolation transformer, characterized in that, include: The first magnetic core (10), the second magnetic core (20), the first winding (30), the second winding (40) and the first PCB insulating board (100); The first magnetic core (10) and the second magnetic core (20) are positioned opposite each other with a first PCB insulating plate (100) horizontally positioned between them. A first winding (30) is disposed on the surface of the first PCB insulating plate (100) facing the first magnetic core (10). The first winding (30) is magnetically coupled to the first magnetic core (10), and the first winding (30) and the first magnetic core (10) constitute the primary side of the transformer. A second winding (40) is disposed on the surface of the first PCB insulating plate (100) facing the second magnetic core (20). The second winding (40) is magnetically coupled to the second magnetic core (20). The second winding (40) is arranged opposite to the first winding (30). The second winding (40) and the second magnetic core (20) constitute the secondary side of the transformer. The first PCB insulating board (100) serves as the electrical insulation medium between the primary winding and the secondary winding of the transformer, as well as between the first magnetic core (10) and the second magnetic core (20). The first magnetic core (10), the second magnetic core (20), the first winding (30), and the second winding (40) are all directly exposed to the air environment.

2. The non-potted medium-voltage insulated high-frequency isolation transformer according to claim 1, characterized in that, The two opposite surfaces of the first PCB insulating board (100) are respectively coated with a semi-conductive coating (110); the coating range of the semi-conductive coating (110) at least completely covers the projection area of ​​the first magnetic core (10), the first winding (30), the second magnetic core (20) and the second winding (40) on the first PCB insulating board (100).

3. A non-potted medium-voltage insulated high-frequency isolation transformer according to claim 1 or 2, characterized in that, An embedded conductive shielding layer (120) is provided between the internal multilayer dielectric layers of the first PCB insulating board (100). The embedded conductive shielding layer (120) is used to transfer and confine the high field strength region at the three-state point formed by the first winding (30), the second winding (40), the first PCB insulating board (100), and the surrounding air to the internal dielectric of the first PCB insulating board (100), thereby suppressing partial discharge in the air at the three-state point.

4. A non-potted medium-voltage insulated high-frequency isolation transformer according to claim 3, characterized in that, The embedded conductive shielding layer (120) includes multiple conductive sheets (121) stacked along the thickness direction of the first PCB insulating board (100). Each conductive sheet (121) is located at a different depth of the internal medium of the first PCB insulating board (100), and adjacent conductive sheets are separated from each other by the internal medium layer of the first PCB insulating board (100). Among them, several layers of conductive sheets (121) and adjacent lower conductive sheets (121) are arranged alternately along the length of the first PCB insulating board (100) to disperse and constrain the high field strength region at the three-state point within the internal medium of the first PCB insulating board (100).

5. A non-potted medium-voltage insulated high-frequency isolation transformer according to claim 2, characterized in that, The portion of the first PCB insulating board (100) extending outward along the periphery of the board surface is the surface extension portion (130).

6. A non-potted medium-voltage insulated high-frequency isolation transformer according to claim 5, characterized in that, A blind groove (140) is formed on at least one surface of the first PCB insulating board (100), and the blind groove (140) is arranged on the surface extension (130).

7. A non-potted medium-voltage insulated high-frequency isolation transformer according to claim 6, characterized in that, The blind slot (140) adopts a continuous closed ring arrangement or a segmented staggered arrangement structure.

8. A non-potted medium-voltage insulated high-frequency isolation transformer according to claim 1, characterized in that, The size of the non-magnetic gap on the magnetic circuit between the first magnetic core (10) and the second magnetic core (20) is equal to the thickness of the first PCB insulating board (100).

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