High-frequency and high-voltage transformer, control method thereof and electric energy conversion structure

Abstract

The invention belongs to a transformer structure, and provides a high-frequency and high-voltage transformer and a control method and an electric energy conversion structure thereof in order to solve the technical problems that an existing fully-encapsulated solid-state transformer is high in cost, electrical performance is sharply reduced after operating temperature rises, and partial discharge occurs after long-time operation. The high-voltage side coil assembly is independently filled and sealed, and the pouring sealant is not integrally filled with the magnetic core, so that the probability that the electrical property is sharply reduced due to the fact that the magnetic core is cracked due to the fact that the thermal expansion coefficients of the pouring sealant and the magnetic core are inconsistent is reduced. The magnetic core is annular and is sleeved on the adjoining edges of the two groups of sub high-voltage side coil assemblies, the two groups of insulating frameworks are respectively sleeved on the two opposite edges of the magnetic core, the low-voltage side coil assembly comprises two groups of sub low-voltage side coil assemblies which are connected in parallel, and the two groups of sub low-voltage side coil assemblies are respectively sleeved on the two groups of insulating frameworks. The heat dissipation plate is installed at the bottom of the high-voltage side coil assembly or the magnetic core.

Description

Technical Field

[0001] The present application relates to a transformer structure, and specifically to a high-frequency and high-voltage transformer, a control method thereof, and an electric energy conversion structure. Background Art

[0002] As the only isolation element in the solid-state transformer system, the high-frequency and high-voltage transformer must achieve high electrical isolation and ensure efficient and reliable power transmission. It has become a key link in determining the conversion efficiency, system cost, and operating life of the solid-state transformer.

[0003] However, when achieving high electrical isolation, existing high-frequency and high-voltage transformers often require the use of a large amount of epoxy resin to fully encapsulate the solid-state transformer, which has the following defects: (1) It is not conducive to cost control; (2) Epoxy resin is an insulating material, and full encapsulation of the solid-state transformer will affect heat dissipation. After the operating temperature of the solid-state transformer rises, the inconsistency in the thermal expansion coefficients of the epoxy resin and the magnetic core will cause the magnetic core to crack, resulting in a sharp decrease in the electrical performance of the solid-state transformer; (3) After a fully encapsulated solid-state transformer has been running for a long time, the electric field strength in the insulating medium of the solid-state transformer will surge, the stress distribution between the media will be uneven, and local discharge will occur, thereby affecting the reliability and service life of the high-frequency and high-voltage transformer. Summary of the invention

[0004] The present application aims to solve the technical problems of existing fully encapsulated solid-state transformers, such as high cost, sharp drop in electrical performance after rising operating temperature, and partial discharge after long-term operation, and to provide a high-frequency and high-voltage transformer, a control method thereof, and an electric energy conversion structure.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions: In a first aspect, the present application proposes a high-frequency high-voltage transformer, including a magnetic core, a low-voltage side coil assembly, a high-voltage side coil assembly, a heat sink, two groups of insulating skeletons, and a plurality of groups of conductive bars; The high-voltage side coil assembly is a potting structure, comprising two groups of sub-high-voltage side coil assemblies arranged side by side, the two groups of sub-high-voltage side coil assemblies are arranged closely, and a receiving hole is formed inside each group of sub-high-voltage side coil assemblies; The magnetic core is annular and is sleeved on the closely adjacent edges of the two groups of sub-high-voltage side coil assemblies, so that the two opposite edges of the magnetic core are respectively located in the two receiving holes; The two groups of insulating frames are respectively sleeved on two opposite sides of the magnetic core; The low-voltage side coil assembly comprises two groups of parallel-connected sub-low-voltage side coil assemblies, and the two groups of sub-low-voltage side coil assemblies are respectively sleeved on two groups of insulating skeletons; A plurality of groups of conductive bars are respectively mounted on the sub-low-voltage side coil assembly and the sub-high-voltage side coil assembly, and extend to the outside of the high-voltage side coil assembly; The heat sink is installed at the bottom of the high-voltage side coil assembly; or, the heat sink is installed at the bottom of the magnetic core; wherein the bottom is either end through which the accommodating hole passes.

[0006] Further, it also includes a low voltage winding coil stay and a high voltage winding coil stay; The heat sink is installed at the bottom of the magnetic core; The low-voltage winding coil support bar is installed between the heat sink and the sub-low-voltage side coil assembly to support the sub-low-voltage side coil assembly; The high-voltage winding coil support bar is installed between the heat dissipation plate and the sub-high-voltage side coil assembly to support the sub-high-voltage side coil assembly.

[0007] Further, the sub-high-voltage side coil assembly includes a high-voltage side coil and a ring mesh cloth; The high-voltage side coil is wound on the ring mesh cloth, an inner metal shielding layer is arranged between the high-voltage side coil and the ring mesh cloth, and the outside of the high-voltage side coil is covered with an inner semi-conductive layer; The inner semi-conductive layers of the two groups of sub-high-voltage side coil assemblies are arranged closely to form a pre-finished high-voltage side coil assembly; The high-voltage side coil assembly pre-finished product is packaged with potting glue on the outside, and the outside of the potting glue is coated with an outer semi-conductive layer.

[0008] Furthermore, the inner metal shielding layer is made of copper foil.

[0009] Furthermore, a gap of 5-20 mm is left between the beginning and the end of the copper foil surrounding the inner wall of the high-voltage side coil, and a metal lead is connected to the copper foil; The metal leads of the two groups of sub-high-voltage side coil assemblies are connected in parallel.

[0010] Furthermore, the conductive bars are provided in four groups; One end of two groups of conductive bars are respectively connected to two groups of sub-low-voltage side coil assemblies, and one end of the other two groups of conductive bars are respectively connected to the metal leads of the two groups of sub-high-voltage side coil assemblies.

[0011] Further, it also includes an insulator; The insulator is connected to the metal lead, and the outside of the insulator is covered with a stress relief belt.

[0012] Furthermore, the heat sink is made of aluminum plate; The conductive bar is made of copper; The insulating framework is an epoxy resin framework.

[0013] In a second aspect, the present application proposes a control method for the high-frequency high-voltage transformer, comprising: By controlling the relative area of ​​the low-voltage side coil assembly and the high-voltage side coil assembly, the leakage inductance of the high-frequency high-voltage transformer is adjusted; By controlling the insulation distance between the magnetic core, the low-voltage side coil assembly and the high-voltage side coil assembly, the high-frequency and high-voltage transformer can be adapted to different voltage-withstand environment requirements.

[0014] In a second aspect, the present application proposes an electric energy conversion structure, including a high voltage module and a low voltage module; and also including the above-mentioned high frequency high voltage transformer; The high-voltage side coil assembly of the high-frequency high-voltage transformer is connected to the high-voltage module, and the low-voltage side coil assembly is connected to the low-voltage module; The high-voltage side coil assembly of the high-frequency high-voltage transformer is connected to an external power electronic conversion module and is used to receive an AC source generated by the power electronic conversion module.

[0015] Compared with the prior art, this application has the following beneficial effects: The present application proposes a high-frequency high-voltage transformer, including a magnetic core, a low-voltage side coil assembly, a high-voltage side coil assembly, a heat sink, two groups of insulating skeletons and multiple groups of conductive bars. The high-voltage side coil assembly is a potting structure, the high-voltage side coil assembly is potted separately, and the potting glue is not potted together with the magnetic core as a whole, which reduces the probability of the magnetic core being cracked due to the inconsistent thermal expansion coefficients of the potting glue and the magnetic core after the high-frequency high-voltage transformer is operated. The reliability of the high-frequency high-voltage transformer can be ensured. The magnetic core is annular and is sleeved on the sides close to the two groups of sub-high-voltage side coil assemblies. The two groups of insulating skeletons are respectively sleeved on the two opposite sides of the magnetic core. The low-voltage side coil assembly includes two groups of parallel sub-low-voltage side coil assemblies. The two groups of sub-low-voltage side coil assemblies are respectively sleeved on the two groups of insulating skeletons. The low-voltage side coil assembly is wound on the inside, and only needs to meet the basic insulation with the magnetic core, and no epoxy resin potting glue is needed, which increases the heat dissipation area. The heat sink is installed at the bottom of the high-voltage side coil assembly or the bottom of the magnetic core. The sub-high-voltage side coil assembly and the sub-low-voltage side coil assembly are used in parallel, which can reduce the coil current density, reduce transformer loss, and improve space utilization and power density. In the high-frequency high-voltage transformer structure of the present application, the insulation distance, the relative area of ​​the low-voltage side coil assembly and the high-voltage side coil assembly can be flexibly adjusted, so that the leakage inductance can be adjusted according to requirements.

[0016] The present application also proposes a control method for the above-mentioned high-frequency and high-voltage transformer and an electric energy conversion structure, which possess all the advantages of the above-mentioned high-frequency and high-voltage transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 An exploded diagram of an embodiment of a high-frequency and high-voltage transformer of the present application; Figure 2 for Figure 1 Assembly diagram of Figure 3 A schematic diagram of a high-voltage side coil assembly in an embodiment of the present application; Figure 4 for Figure 3 AA section view; Figure 5 for Figure 4 A partial enlarged view of the metal shielding layer on the inner side; Figure 6 This is a schematic diagram of the principles of the high-voltage side coil assembly, the low-voltage side coil assembly and the inner metal shielding layer in the embodiment of the present application; Figure 7 A schematic diagram of the electric energy conversion structure of the present application.

[0019] Among them: 1-magnetic core, 2-insulating skeleton, 3-sub-low-voltage side coil assembly, 4-high-voltage side coil assembly, 4.1-stress relief belt, 4.2-potting glue, 4.3-ring mesh cloth, 4.4-high-voltage side coil, 4.5-inner metal shielding layer, 4.6-inner semi-conductive layer, 4.7-outer semi-conductive layer, 5-conductive bar, 6-heat sink, 7-low-voltage winding coil support bar, 8-high-voltage winding coil support bar. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0022] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0023] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the invented product is usually placed when used. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0024] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0025] In the description of the embodiments of the present application, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0026] In the power electronics industry, as the installed capacity of new energy sources continues to increase, power electronics equipment is also developing towards higher voltage levels and greater power capacity. The capacity of DC loads such as data centers and electric vehicle super charging is constantly increasing, and power electronics equipment that connects DC loads to the power grid is also facing new challenges. It must be able to achieve power conversion efficiently and reliably, and also have fault isolation functions between the power grid.

[0027] High-frequency and high-voltage transformers can simultaneously meet high electrical isolation requirements and reliable power transmission. There are two main production methods: (1) Oil-immersed transformer: uses insulating oil as the main insulating medium, but oil is a flammable substance and is not suitable for use in a closed environment.

[0028] (2) Epoxy cast integrated transformer: The winding and the magnetic core are cast in epoxy resin as a whole to fully encapsulate the high-frequency and high-voltage transformer.

[0029] In order to achieve high electrical isolation performance, existing high-frequency and high-voltage transformers generally adopt the second full potting method, but usually have the following problems: (1) Cost issue.

[0030] The full potting method uses epoxy resin as the potting material. The price of epoxy resin is relatively high. Since a large amount of epoxy resin is required for full potting, the material cost of the high-frequency and high-voltage transformer will be greatly increased.

[0031] (2) Heat dissipation efficiency problem.

[0032] The potting material will cover the heat dissipation channel inside the high-frequency high-voltage transformer, making it difficult to dissipate heat, thus affecting the stable operation of the high-frequency high-voltage transformer. In addition, the epoxy resin and the magnetic core have different thermal expansion coefficients when the temperature changes. This mismatch may cause the magnetic core to be subjected to additional stress, resulting in tensile cracks. The cracks will not only reduce the mechanical strength of the magnetic core, but may also affect the electrical performance.

[0033] (3) The problem of electrical performance degradation.

[0034] Based on problem (2), cracks in the magnetic core may lead to uneven distribution of the electromagnetic field, thus affecting the output voltage and current stability of the high-frequency high-voltage transformer. In addition, cracks may also increase the risk of partial discharge, further damaging the electrical performance of the high-frequency high-voltage transformer.

[0035] (4) Problems of electric field strength and stress distribution inside insulating media.

[0036] Long-term operation of high-frequency and high-voltage transformers may lead to uneven distribution of electric field strength inside the insulating medium, causing some areas to be subjected to excessive electric field strength, thereby increasing the risk of partial discharge. The stress distribution between the insulating medium may also change due to long-term operation, causing some areas to be subjected to excessive stress, which in turn causes insulation damage.

[0037] Based on the above situation, the present application proposes a high-frequency and high-voltage transformer and a control method thereof, and an electric energy conversion structure. The present application is described in detail below in conjunction with embodiments and drawings.

[0038] As an embodiment of the high-frequency and high-voltage transformer of the present application, it may include a magnetic core 1, a low-voltage side coil assembly, a high-voltage side coil assembly 4, a heat sink 6, two groups of insulating frames 2 and multiple groups of conductive bars 5.

[0039] The high-voltage side coil assembly 4 is a potting structure, including two groups of sub-high-voltage side coil assemblies arranged side by side. The two groups of sub-high-voltage side coil assemblies are arranged closely, and a receiving hole is formed inside each group of sub-high-voltage side coil assemblies. The high-voltage side coil assembly 4 adopts a potting structure, which is different from the fully potted structure of the existing high-frequency high-voltage transformer. It can also protect the high-voltage side coil assembly 4 from the influence of the external environment, reduce electromagnetic interference, and improve safety. The two groups of sub-high-voltage side coil assemblies are arranged side by side and close to form two receiving holes. Such a layout optimizes the installation position of the magnetic core 1 and ensures the efficient transfer of magnetic flux.

[0040] The magnetic core 1 is annular and is sleeved on the edges of the two groups of sub-high-voltage side coil assemblies, so that the two opposite edges of the magnetic core 1 are respectively located in the two receiving holes. The magnetic core 1 adopts an annular design, which can effectively concentrate the magnetic field, reduce leakage magnetic flux, and improve energy conversion efficiency. The magnetic core 1 is sleeved on the edges of the two groups of sub-high-voltage side coil assemblies. This design allows each side of the magnetic core 1 to be tightly coupled with the corresponding sub-high-voltage side coil assembly, thereby enhancing the utilization rate of the magnetic field.

[0041] The two sets of insulating skeletons 2 are respectively sleeved on two opposite sides of the magnetic core 1. The two sets of insulating skeletons 2 provide a support structure for the low-voltage side coil assembly, and also ensure electrical isolation between the coil and the magnetic core to prevent short circuit. In practical applications, the insulating skeleton 2 can be made of high-performance insulating materials that can withstand high voltage without being broken down.

[0042] The low-voltage side coil assembly includes two groups of parallel sub-low-voltage side coil assemblies 3, and the two groups of sub-low-voltage side coil assemblies 3 are respectively sleeved on two groups of insulating skeletons 2. The low-voltage side coil assembly and the high-voltage side coil assembly 4 are coupled through the magnetic core 1 to achieve voltage up and down conversion. The installation method of the low-voltage side coil assembly in this application also takes into account the needs of heat dissipation and electrical insulation.

[0043] A plurality of conductive bars 5 are respectively mounted on the sub-low-voltage side coil assembly 3 and the sub-high-voltage side coil assembly, and extend to the outside of the high-voltage side coil assembly 4. The conductive bars 5 are provided to connect the low-voltage side coil assembly and the external circuit, and the high-voltage side coil assembly 4 and the external circuit, thereby realizing the input and output of electric energy.

[0044] The heat sink 6 is installed at the bottom of the high-voltage side coil assembly 4; or, the heat sink 6 is installed at the bottom of the magnetic core 1; wherein the bottom refers to either end through which the receiving hole passes. The provision of the heat sink 6 enables the high-frequency and high-voltage transformer to dissipate heat effectively, and prevents performance degradation or damage caused by overheating of the low-voltage side coil assembly and the high-voltage side coil assembly 4. In practical applications, the material of the heat sink 6 can be selected from high thermal conductivity materials, such as aluminum or copper, and the heat dissipation path can be optimized through thermal design to ensure the long-term stable operation of the high-frequency and high-voltage transformer.

[0045] like Figure 1 As shown, it is an exploded view of an embodiment of the high-frequency high-voltage transformer of the present application, as shown Figure 2 As shown, Figure 1 The present application is further described by means of this embodiment as follows.

[0046] The magnetic core 1 is assembled by multiple pairs of UU-type magnetic cores, and the open ends of each pair of UU-type magnetic cores are placed opposite to each other and assembled in an aligned manner up and down. In practical applications, the number of pairs of UU-type magnetic cores can be adjusted according to the capacity requirements of the high-frequency and high-voltage transformer. In this embodiment, 4 pairs of UU-type magnetic cores are used. Each pair of UU-type magnetic cores has two parallel legs and a top and bottom connecting the two legs. This design enables the magnetic core 1 to form a closed magnetic circuit, thereby improving the efficiency and intensity of the magnetic field. By assembling multiple pairs of UU-type magnetic cores, a longer magnetic circuit or a more complex magnetic field structure can be formed, increasing the flexibility and scalability of the magnetic core 1. As an example, the magnetic core 1 can adopt a ferrite core. At high frequencies, the magnetic core 1 has low loss, is easy to form and assemble, can flexibly adjust the inductance, is widely used in the market, and has low cost. In other embodiments of the present application, the UU-type magnetic core can also be replaced by an EE-type magnetic core.

[0047] The insulating skeleton 2 is mounted on the two legs of the UU-shaped magnetic core and is used to insulate the low-voltage side coil assembly and the magnetic core 1. The insulating skeleton 2 keeps the low-voltage side coil assembly away from the air gap scattered magnetic flux at the junction of the magnetic core 1, which can effectively reduce the eddy current loss caused by the scattered magnetic flux of the low-voltage side coil assembly. In this embodiment, the insulating skeleton 2 is made of epoxy resin material. It should be noted that the primary function of the insulating skeleton 2 is to provide electrical isolation between the low-voltage side coil assembly and the magnetic core 1, to prevent the current from flowing directly from the low-voltage side coil assembly to the magnetic core 1, or to form an unexpected electrical connection between the two, thereby ensuring the safety and stability of the circuit. In addition, at the junction of the magnetic core 1, especially near the air gap, the magnetic field lines may diverge (scattered magnetic flux). If such divergent magnetic field lines pass directly through the low-voltage side coil assembly, eddy currents will be generated in the coil, thereby causing energy loss (eddy current loss). The insulating skeleton 2 effectively reduces eddy current losses and improves the efficiency of the equipment by isolating the low-voltage side coil assembly from these divergent magnetic field lines.

[0048] The sub-low-voltage side coil assembly 3 is in the shape of a hollow cube and is mounted in the insulating skeleton 2. In practical applications, the sub-low-voltage side coil assembly 3 can be wound by fully transposed Litz wire, which reduces the skin effect and proximity effect at high frequencies, thereby reducing the high-frequency AC loss of the sub-low-voltage side coil assembly 3. Two groups of sub-low-voltage side coil assemblies 3 are used in parallel to reduce the current density of the sub-low-voltage side coil assembly 3 and reduce the temperature rise and loss of the high-frequency high-voltage transformer. As an example, the outer insulation level of the Litz wire adopts H level or higher, and the temperature resistance is not less than 180°C, ensuring that the high-frequency high-voltage transformer will not fail in insulation during long-term operation under load, thereby ensuring the operation stability of the high-frequency high-voltage transformer. The benefit of placing the sub-low-voltage side coil assembly 3 on the inside of the receiving hole is that there is no great insulation requirement between the sub-low-voltage side coil assembly 3 and the magnetic core 1 and the ground, which can effectively save space and increase the overall power density of the high-frequency high-voltage transformer. In practical applications, the low-voltage side coil assembly only needs to meet the basic insulation with the magnetic core 1, and there is no need to use potting glue such as epoxy resin, which increases the heat dissipation area.

[0049] like Figure 3 As shown, it is a schematic diagram of the high-voltage side coil assembly 4, such as Figure 4 As shown, Figure 3 The AA section view is as follows: Figure 5 As shown, it is a partial enlarged view of the inner metal shielding layer 4.5. The high-voltage side coil assembly 4 is a cubic vertical structure as a whole, and may include a high-voltage side coil 4.4 and a ring mesh cloth 4.3. The high-voltage side coil 4.4 is wound on the ring mesh cloth 4.3, and an inner metal shielding layer 4.5 is arranged between the high-voltage side coil 4.4 and the ring mesh cloth 4.3, and the outer side of the high-voltage side coil 4.4 is coated with an inner semi-conductive layer 4.6. The inner semi-conductive layers 4.6 of the two groups of sub-high-voltage side coil assemblies are arranged closely to form a pre-finished product of the high-voltage side coil assembly. The outer part of the pre-finished product of the high-voltage side coil assembly is encapsulated with a potting glue 4.2, and the outer part of the potting glue 4.2 is coated with an outer semi-conductive layer 4.7. The ring mesh cloth 4.3 can provide support and fixing to ensure that the high-voltage side coil 4.4 maintains a stable shape and position during operation.

[0050] In the actual preparation process, the ring mesh cloth 4.3 made of epoxy material can be wound first, leaving the insulation distance between the high-voltage side coil assembly 4 and the low-voltage side coil assembly to ensure the primary and secondary side withstand voltage isolation requirements of the high-frequency high-voltage transformer, and then the high-voltage side coil 4.4 can be wound. The high-voltage side coil 4.4 can be wound by fully transposed Litz wire to reduce the skin effect and proximity effect at high frequency, thereby reducing the high-frequency AC loss of the high-voltage side coil 4.4. The two groups of sub-high-voltage side coil assemblies are used in parallel to reduce the coil current density and reduce the temperature rise and loss of the high-frequency high-voltage transformer. The outer layer insulation grade of the Litz wire can be H grade or higher, and the temperature resistance is usually not less than 180°C, which ensures that the high-frequency high-voltage transformer will not fail in insulation during long-term operation under load, thereby ensuring the operation stability of the high-frequency high-voltage transformer. Then use the inner metal shielding layer 4.5 to wrap around the inner side of the high-voltage side coil 4.4, leaving a distance of 5-20mm between the head and tail of the inner metal shielding layer 4.5, and weld the metal lead to lead out the inner metal shielding layer 4.5. The inner metal shielding layers 4.5 of the two groups of sub-high-voltage side coil assemblies are led out and connected in parallel. Then use the semi-conductive layer material to cover the high-voltage side coil 4.4 to form the inner semi-conductive layer 4.6. Then put the high-voltage side coil 4.4 with the inner metal shielding layer 4.5 and the inner semi-conductive layer 4.6 as a semi-finished product in the potting mold, and reserve enough insulation distance around to ensure the withstand voltage. Then vacuum heating potting is performed, and the potting material is epoxy resin potting glue with a thermal conductivity of 1-3W (m·K) to ensure that the heat of the sub-high-voltage side coil assembly after potting is conducted out. The grade of the ring mesh cloth 4.3 and the potting glue 4.2 after curing is usually H grade, and the temperature resistance is usually not less than 180℃. Then, after the potting glue 4.2 is cured and demoulded, an outer semi-conductive layer 4.7 is added to the periphery of the potting glue 4.2 as a grounded outer shielding structure. After coating, the outer semi-conductive layer 4.7 can be tightly attached to the surface of the potting glue 4.2, and all electrical stresses are constrained in the potting glue 4.2 to eliminate partial discharge in the air gap outside the potting glue 4.2. Figure 6 As shown, it is a schematic diagram of the principle of the high-voltage side coil assembly 4, the low-voltage side coil assembly and the inner metal shielding layer 4.5. Figure 6 In the figure, X represents the low voltage side coil assembly.

[0051] In some embodiments of the present application, when the sub-high-voltage side coil assembly is potted, an insulator can be added to the metal lead of the high-voltage side coil 4.4, and a high-dielectric stress relief tape 4.1 can be coated on the outside of the insulator. The insulator can increase the creepage distance between the high-voltage side coil 4.4 and the ground. The high-dielectric stress relief tape 4.1 can improve the situation that causes serious distortion of the electric field distribution along the surface of the outgoing line end, make the electric field distribution uniform, and control the local discharge situation within the standard.

[0052] In some embodiments of the present application, the conductive bar 5 is a copper bar, and the conductive bar 5 is respectively connected to the tail of the high-voltage side coil assembly 4 and the low-voltage side coil assembly to facilitate electrical connection with the high-voltage module and the low-voltage module of the external circuit.

[0053] After the insulation distance between the high-voltage side coil assembly 4 and the low-voltage side coil assembly is reserved, the high-voltage side coil assembly 4 is potted as a whole. Since the thermal conductivity of the epoxy resin potting glue is 1-3W (m·K), the heat dissipation of the high-voltage side coil assembly 4 can be increased. On the basis of ensuring the insulation withstand voltage, the amount of epoxy resin can be greatly reduced, thereby reducing costs and increasing the heat dissipation area of ​​the overall high-frequency high-voltage transformer. The low-voltage side coil assembly and the high-voltage side coil assembly 4 can be flexibly assembled and matched. Even if the withstand voltage is poor, the undamaged low-voltage side coil assembly and the high-voltage side coil assembly 4 can be reused to reduce costs and improve economic benefits.

[0054] The heat sink 6 can also be used to fix the high-frequency high-voltage transformer, and epoxy resin glue is used to cure and assemble the bottom of the magnetic core 1 to conduct the heat generated by the high-frequency high-voltage transformer. In this embodiment, the heat sink 6 can be made of an aluminum plate, or it can be replaced by an insulating plate. In addition, it can also be fixed with a support plate or a pull rod.

[0055] In addition, when the heat sink 6 is installed at the bottom of the magnetic core 1, a low-voltage winding coil support bar 7 and a high-voltage winding coil support bar 8 can be set, and the low-voltage winding coil support bar 7 is installed between the heat sink 6 and the sub-low-voltage side coil assembly 3, and the high-voltage winding coil support bar 8 is installed between the heat sink 6 and the sub-high-voltage side coil assembly. Among them, when assembling a high-frequency and high-voltage transformer, the low-voltage winding coil support bar 7 can place the low-voltage side coil assembly in the middle position of the magnetic core 1, play a supporting role, so that the low-voltage side coil assembly will not press on the magnetic core 1, while ensuring insulation, it can also increase the stability of the low-voltage side coil assembly, and avoid the magnetic core 1 being crushed due to the low-voltage side coil assembly pressing on the magnetic core 1, affecting the electrical performance. When assembling a high-frequency high-voltage transformer, the high-voltage winding coil support bar 8 makes the high-voltage side coil assembly 4 located in the middle of the magnetic core 1, plays a supporting role, and prevents the high-voltage side coil assembly 4 from pressing on the magnetic core 1, ensuring insulation while increasing the stability of the high-voltage side coil assembly 4, and preventing the high-voltage side coil assembly 4 from pressing on the magnetic core 1, crushing the magnetic core 1, and affecting electrical performance. The low-voltage winding coil support bar 7 and the high-voltage winding coil support bar 8 can also prevent the low-voltage side coil assembly and the high-voltage side coil assembly 4 from falling, resulting in insufficient insulation distance between the magnetic core 1 and poor withstand voltage.

[0056] The high-frequency high-voltage transformer manufacturing method of the present application is simple, easy to form and assemble, and can flexibly adjust the inductance. The high-voltage side coil assembly 4 is potted separately, and the potting glue 4.2 is not integrally poured together with the magnetic core 1, which effectively reduces the probability of the magnetic core 1 being cracked due to the inconsistent thermal expansion coefficients of the epoxy resin and the magnetic core 1 after the operating temperature of the high-frequency high-voltage transformer increases, and will not cause a sharp decrease in electrical performance, thereby ensuring the reliability of the high-frequency high-voltage transformer.

[0057] The present application also proposes a control method for the high-frequency high-voltage transformer, which may include: By controlling the relative area of ​​the low-voltage side coil assembly and the high-voltage side coil assembly 4, the leakage inductance of the high-frequency high-voltage transformer is adjusted; By controlling the insulation distances between the magnetic core 1 , the low-voltage side coil assembly and the high-voltage side coil assembly 4 , the high-frequency and high-voltage transformer can be adapted to different withstand voltage environment requirements.

[0058] In practical applications, in the LLC (indicating two inductors and one capacitor) resonant converter topology, the leakage inductance can be used as a resonant inductor, so that the high-frequency transformer circuit using the high-frequency and high-voltage transformer of the present application does not require an external resonant inductor, thereby reducing the use of components, saving space, reducing costs, and increasing economic benefits.

[0059] like Figure 7 As shown, it is a schematic diagram of the electric energy conversion structure of the present application, Figure 7 In the figure, the numbers "4" and "4.5" are both figure marks, representing the high-voltage side coil assembly 4 and the inner metal shielding layer 4.5, and X represents the low-voltage side coil assembly. The electric energy conversion structure may include a high-voltage module, a low-voltage module and the aforementioned high-frequency high-voltage transformer. The high-voltage side coil assembly 4 of the high-frequency high-voltage transformer is connected to the high-voltage module, the low-voltage side coil assembly is connected to the low-voltage module, and the high-voltage side coil assembly 4 of the high-frequency high-voltage transformer is connected to an external power electronic conversion module for receiving the AC source generated by the power electronic conversion module.

[0060] When the power electronic conversion module generates an AC source, an alternating magnetic flux will be generated in the magnetic core 1, thereby generating an alternating magnetic field, and the low-voltage side coil assembly will generate an induced electromotive force, completing the energy transfer and realizing the conversion of electric energy with one power characteristic into electric energy with another power characteristic, thereby centrally realizing the functions of electrical isolation, voltage conversion, reactive power compensation, power transmission and control, and bidirectional energy flow.

[0061] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A high frequency high voltage transformer, characterized in that: It comprises a magnetic core (1), a low-voltage side coil assembly, a high-voltage side coil assembly (4), a heat sink (6), two groups of insulating frames (2) and a plurality of groups of conductive bars (5); The high-voltage side coil assembly (4) is a potting structure, comprising two groups of sub-high-voltage side coil assemblies arranged side by side, the two groups of sub-high-voltage side coil assemblies are arranged closely together, and a receiving hole is formed inside each group of sub-high-voltage side coil assemblies; The magnetic core (1) is annular and is sleeved on the closely adjacent edges of the two groups of sub-high-voltage side coil assemblies, so that two opposite edges of the magnetic core (1) are respectively located in the two receiving holes; The two groups of insulating frames (2) are respectively sleeved on two opposite sides of the magnetic core (1); The low-voltage side coil assembly comprises two groups of parallel-connected sub-low-voltage side coil assemblies (3), and the two groups of sub-low-voltage side coil assemblies (3) are respectively sleeved on two groups of insulating skeletons (2); A plurality of groups of conductive bars (5) are respectively mounted on the sub-low-voltage side coil assembly (3) and the sub-high-voltage side coil assembly, and extend toward the outside of the high-voltage side coil assembly (4); The heat sink (6) is installed at the bottom of the high-voltage side coil assembly (4); or, the heat sink (6) is installed at the bottom of the magnetic core (1); wherein the bottom is either end through which the receiving hole passes.

2. The high-frequency high-voltage transformer according to claim 1, characterized in that: It also includes a low-voltage winding coil support bar (7) and a high-voltage winding coil support bar (8); The heat sink (6) is installed at the bottom of the magnetic core (1); The low-voltage winding coil support bar (7) is installed between the heat sink (6) and the sub-low-voltage side coil assembly (3) and is used to support the sub-low-voltage side coil assembly (3); The high-voltage winding coil support bar (8) is installed between the heat sink (6) and the sub-high-voltage side coil assembly and is used to support the sub-high-voltage side coil assembly.

3. The high-frequency high-voltage transformer according to claim 1, characterized in that: The sub-high-voltage side coil assembly comprises a high-voltage side coil (4.4) and a ring mesh cloth (4.3); The high-voltage side coil (4.4) is wound on the ring mesh cloth (4.3), an inner metal shielding layer (4.5) is provided between the high-voltage side coil (4.4) and the ring mesh cloth (4.3), and the high-voltage side coil (4.4) is coated with an inner semi-conductive layer (4.6) on the outside; The inner semi-conductive layers (4.6) of the two groups of sub-high-voltage side coil assemblies are arranged closely together to form a pre-finished high-voltage side coil assembly; The high-voltage side coil assembly pre-finished product is externally packaged with a potting glue (4.2), and the potting glue (4.2) is externally coated with an outer semi-conductive layer (4.7).

4. The high-frequency high-voltage transformer according to claim 3, characterized in that: The inner metal shielding layer (4.5) is made of copper foil.

5. The high frequency and high voltage transformer according to claim 4, characterized in that: A gap of 5-20 mm is left between the beginning and the end of the copper foil surrounding the inner wall of the high-voltage side coil (4.4), and a metal lead is connected to the copper foil; The metal leads of the two groups of sub-high-voltage side coil assemblies are connected in parallel.

6. The high frequency and high voltage transformer according to claim 5, characterized in that: The conductive bars (5) are provided in four groups; One end of two groups of conductive bars (5) are respectively connected to two groups of sub-low-voltage side coil assemblies (3), and one end of the other two groups of conductive bars (5) are respectively connected to the metal leads of the two groups of sub-high-voltage side coil assemblies.

7. The high frequency and high voltage transformer according to claim 6, characterized in that: Also includes insulators; The insulator is connected to the metal lead, and the outside of the insulator is coated with a stress relief band (4.1).

8. The high frequency and high voltage transformer according to claim 7, characterized in that: The heat dissipation plate (6) is made of an aluminum plate; The conductive bar (5) is a copper bar; The insulating frame (2) is an epoxy resin frame.

9. A control method for a high-frequency and high-voltage transformer according to any one of claims 1 to 8, characterized in that: include: By controlling the relative area of ​​the low-voltage side coil assembly and the high-voltage side coil assembly (4), the leakage inductance of the high-frequency high-voltage transformer is adjusted; By controlling the insulation distance between the magnetic core (1), the low-voltage side coil assembly and the high-voltage side coil assembly (4), the high-frequency and high-voltage transformer can be adapted to different withstand voltage environment requirements.

10. An electric energy conversion structure, comprising a high voltage module and a low voltage module; characterized in that: Also includes the high frequency and high voltage transformer as claimed in any one of claims 1 to 8; The high-voltage side coil assembly (4) of the high-frequency high-voltage transformer is connected to the high-voltage module, and the low-voltage side coil assembly is connected to the low-voltage module; The high-voltage side coil component (4) of the high-frequency high-voltage transformer is connected to an external power electronic conversion module and is used to receive an AC source generated by the power electronic conversion module.

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