Power conversion device

Abstract

The application discloses a power conversion device, and belongs to the technical field of power electronics. The power conversion device comprises a box body, a transformer body and a first conversion module arranged in the box body. At least one side surface of the box body is provided with a low-voltage sleeve and a high-voltage sleeve. The transformer body comprises a core column, a high-voltage winding and a low-voltage winding arranged in sequence from inside to outside. The input side of the first conversion module is electrically connected with the low-voltage winding, and the output side of the first conversion module is electrically connected with the low-voltage sleeve. The voltage frequency of the input side of the first conversion module is higher than that of the output side of the first conversion module. The low-voltage winding can be converted into low-frequency alternating current or direct current in the box body, and then the low-frequency alternating current or direct current is led out through the low-voltage sleeve. Thus, the high-frequency lead wire penetrating through the box body is omitted, the problem of eddy current loss caused by the high-frequency magnetic field of the lead wire on the box body is solved, the hidden danger of overheating of the box body is improved, and the efficiency of the whole machine is improved.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a power conversion device. Background Technology

[0002] Large-capacity, medium-frequency, medium-voltage power converters operate at relatively high frequencies, making them prone to additional eddy current losses in the magnetic core and windings. Simultaneously, the high-frequency alternating magnetic field generated by the windings couples to the inner wall of the enclosure, fixing clamps, and other surrounding metal components, inducing stray losses. Common solutions involve increasing the installation distance between the metal structural components and the windings to avoid the high-frequency, strong magnetic field area, thus suppressing most stray losses. However, the low-voltage output of the power converter is a high-current loop, and the positive and negative leads on the low-voltage side need to penetrate the enclosure. The high-frequency magnetic field carried by these leads is difficult to avoid, easily forming eddy currents on the enclosure and causing localized overheating. This reduces the power converter's operating efficiency and poses a safety hazard of overheating failure. Summary of the Invention

[0003] This application provides a power conversion device to at least partially solve the above-mentioned technical problems.

[0004] To achieve the above objectives, according to a first aspect of this application, a power conversion device is provided, the power conversion device comprising: The enclosure, wherein at least one surface of the enclosure is provided with a low-pressure sleeve and a high-pressure sleeve; A transformer body, disposed within the housing, includes a core, a high-voltage winding, and a low-voltage winding. The high-voltage winding is sleeved around the outer periphery of the core and radially insulated from it. The low-voltage winding is sleeved around the outer periphery of the high-voltage winding and radially insulated from it. A first conversion module is disposed within the housing. The first conversion module has an input side and an output side. The input side of the first conversion module is electrically connected to the low-voltage winding, and the output side of the first conversion module is electrically connected to the low-voltage bushing. The voltage frequency of the input side of the first conversion module is higher than the voltage frequency of the output side of the first conversion module.

[0005] In some embodiments, the housing is filled with an insulating liquid, and the first conversion module is immersed in the insulating liquid.

[0006] In some embodiments, the power conversion device further includes two end fixing members and a plurality of fixing posts, wherein the two end fixing members are respectively disposed at both ends of the transformer body in the axial direction, and each fixing post connects the two end fixing members; The first conversion module is disposed between the low-voltage winding and the inner wall of the housing and is connected to the two end fixing members.

[0007] In some embodiments, the power conversion device further includes a fixing plate and a connecting plate; the fixing plate is disposed between the low-voltage winding, the first conversion module and the inner wall of the housing, and the two ends of the fixing plate along the axial direction are respectively connected to the end fixing member through the connecting plate.

[0008] In some embodiments, the component packaging material of the first conversion module is chemically compatible with the insulating liquid.

[0009] In some embodiments, the power conversion device further includes a sealing structure, both the sealing structure and the first conversion module are disposed on the inner wall of the housing, and the sealing structure covers the outer periphery of the first conversion module.

[0010] In some embodiments, the input side of the first conversion module is electrically connected to the low-voltage winding via a first lead, the output side of the first conversion module is electrically connected to the low-voltage bushing via a second lead, and the high-voltage winding is electrically connected to the high-voltage bushing via a third lead.

[0011] In some embodiments, the power conversion device further includes a second conversion module, which is disposed outside the housing and electrically connected to the transformer body, wherein the output voltage of the second conversion module is greater than the output voltage of the first conversion module.

[0012] In some embodiments, the power conversion device further includes: A heat dissipation structure is connected to the housing.

[0013] In some embodiments, the power conversion device further includes an insulating support structure, which is radially disposed between the core post and the high-voltage winding, and between the high-voltage winding and the low-voltage winding.

[0014] In some embodiments, the high-voltage winding includes a plurality of first winding layers arranged coaxially in the radial direction, and the plurality of first winding layers are electrically connected to each other; each first winding layer is formed by winding multiple turns of first coil layer by layer in the axial direction; The insulating support structure is also radially disposed between any two adjacent first winding layers.

[0015] In some embodiments, when at least two adjacent first winding layers are interconnected, the innermost first winding layer is provided with a first connection end, and the outermost first winding layer is provided with a second connection end.

[0016] In some embodiments, the low-voltage winding includes a plurality of second winding layers, the plurality of second winding layers being stacked axially and coaxially arranged, each second winding layer including a disc segment and a cylindrical segment connected axially; The disc-shaped segment includes multiple turns of first thread layers, which are concentrically wound radially from the outside to the inside, and the outermost first thread layer is provided with a third connecting end; the cylindrical segment includes multiple turns of cylindrical sub-segments, which are arranged radially and connected to each other, and each cylindrical sub-segment includes multiple turns of second thread layers arranged axially, the outermost second thread layer is provided with a fourth connecting end, and the innermost first thread layer and the innermost cylindrical sub-segment's second thread layer are connected.

[0017] In some embodiments, the first connection terminal and the second connection terminal are both located on the same side of the high-voltage winding, and the third connection terminal and the fourth connection terminal are both located on the same side of the low-voltage winding; The first connecting end and the second connecting end have a first orthographic projection on the reference plane, and the third connecting end and the fourth connecting end have a second orthographic projection on the reference plane. The first orthographic projection and the second orthographic projection do not coincide, wherein the reference plane is perpendicular to the axial direction.

[0018] In some embodiments, the number of low-voltage windings is multiple, and the number of low-voltage windings is greater than the number of high-voltage windings.

[0019] In some embodiments, the insulating support structure includes an annular support unit, the annular support unit including an annular body and a plurality of axially extending spacers disposed on the annular body, the plurality of spacers being spaced apart circumferentially along the annular body; The annular support unit abuts radially against the circumferential surface of the high-voltage winding or the circumferential surface of the low-voltage winding to define at least one first fluid channel.

[0020] In some embodiments, the annular body of the annular support unit is configured as a first insulating support ring, and the spacer member includes a plurality of first support bars, which are spaced apart circumferentially on the first insulating support ring. The first support bars abut against the circumferential surface of the high-voltage winding or the circumferential surface of the low-voltage winding in the radial direction; or... The annular body of the ring support unit is configured as a second insulating support ring. The spacer member includes a plurality of second support bars, which are spaced apart on the second insulating support ring along the circumference. Each second support bar includes a first support segment and two second support segments. The two second support segments are respectively connected to the two ends of the first support segment in the axial direction. The first support segment abuts against the circumferential surface of the high-voltage winding or the circumferential surface of the low-voltage winding in the radial direction. A gap is provided between the second support segment and the circumferential surface of the high-voltage winding or the circumferential surface of the low-voltage winding in the radial direction.

[0021] In some embodiments, the insulating support structure includes a plurality of coaxially arranged annular support units, each annular support unit including an annular body and a plurality of axially extending spacers disposed on the annular body, the plurality of spacers being spaced apart circumferentially along the annular body; In one of the annular support units, the spacer member abuts radially against the circumferential surface of the high-voltage winding or the circumferential surface of the low-voltage winding to define at least one first fluid channel, and the spacer member of the other annular support unit abuts against the annular body of the adjacent annular support unit to define at least one second fluid channel.

[0022] In some embodiments, the annular support unit includes a first insulating support ring and a second insulating support ring; the first insulating support ring and the second insulating support ring are coaxially arranged; the spacer includes a plurality of first support bars and a plurality of second support bars, the plurality of first support bars being spaced apart on the first insulating support ring along the circumference; the plurality of second support bars being spaced apart on the second insulating support ring along the circumference; each second support bar includes a first support segment and two second support segments, the two second support segments being respectively connected to the two ends of the first support segment in the axial direction; When the second insulating support ring is disposed on the outer periphery of the first insulating support ring, the first support bar on the first insulating support ring abuts against the inner wall of the adjacent second insulating support ring, the first support segment abuts against the circumferential surface of the high voltage winding or the circumferential surface of the low voltage winding in the radial direction, and the second support segment has a gap between itself and the circumferential surface of the high voltage winding or the circumferential surface of the low voltage winding in the radial direction. When the first insulating support ring is disposed on the outer periphery of the second insulating support ring, the first support segment abuts against the inner wall of the first insulating support ring in the radial direction, the second support segment has the gap between it and the first insulating support ring in the radial direction, and the first support bar on the first insulating support ring abuts against the circumferential surface of the high voltage winding or the circumferential surface of the low voltage winding in the radial direction.

[0023] In some embodiments, when there are two or more first insulating support rings and two first insulating support rings are arranged adjacent to each other, the first support bar on one of the first insulating support rings abuts against the adjacent first insulating support ring in the radial direction to define at least one second fluid channel. When there are two or more second insulating support rings and two second insulating support rings are arranged adjacent to each other, the first support segment on one of the second insulating support rings abuts against the adjacent second insulating support ring in the radial direction to define at least one second fluid channel, and the second support segment is provided with the gap between itself and the adjacent second insulating support ring in the radial direction.

[0024] In some embodiments, the annular body and the spacer are integrally formed.

[0025] In the power conversion device of this application, a first conversion module is installed inside the enclosure. Utilizing the conversion characteristic that the voltage frequency on its input side is higher than that on its output side, the high-frequency AC power from the low-voltage winding is converted into low-frequency AC or DC power inside the enclosure before being led out through a low-voltage bushing. This eliminates the need for high-frequency leads extending out of the enclosure, thus solving the problem of eddy current losses caused by the high-frequency magnetic field of the leads on the enclosure, improving the risk of overheating of the enclosure, and increasing the overall efficiency. It also eliminates the need to increase the spacing between the winding structure and the metal parts of the enclosure, facilitating a compact layout of the power conversion device and increasing power density. Simultaneously, the low-voltage bushing only transmits low-frequency AC / DC power, reducing the difficulty of bushing insulation design. Furthermore, the conversion module, placed inside the enclosure, can rely on the internal medium for heat dissipation, improving the reliability of the equipment operation.

[0026] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0029] Figure 1 This is a schematic diagram of the structure of the power conversion device provided in an exemplary embodiment of this application. Figure 1 ; Figure 2This is an internal cross-sectional view of the transformer body provided in an exemplary embodiment of this application; Figure 3 This is a schematic diagram of the high-voltage winding structure provided in an exemplary embodiment of this application, mainly illustrating the structure of a first winding layer; Figure 4 This is a schematic diagram of the insulating support structure provided in an exemplary embodiment of this application, which is disposed in two adjacent first winding layers; Figure 5 yes Figure 4 A cross-sectional view along the AA direction; Figure 6 This is a partial structural diagram of the power conversion device provided in an exemplary embodiment of this application, mainly showing that the low-voltage winding is disposed on the outer periphery of the high-voltage winding; Figure 7 This is a schematic diagram of the winding structure of the low-voltage winding provided in an exemplary embodiment of this application; Figure 8 This is a schematic diagram of the structure of the low-voltage winding provided in an exemplary embodiment of this disclosure. Figure 1 ; Figure 9 This is a schematic diagram of the structure of the low-voltage winding provided in an exemplary embodiment of this disclosure. Figure 2 ; Figure 10 This is a half-bridge topology diagram provided in an exemplary embodiment of this disclosure; Figure 11 This is a full-bridge topology diagram provided in an exemplary embodiment of this disclosure; Figure 12 This is a topology diagram of a power conversion device provided in an exemplary embodiment of this disclosure; Figure 13 This is a schematic diagram of the structure of the power conversion device provided in an exemplary embodiment of this application. Figure 2 ; Figure 14 This is a schematic diagram of the structure of the annular support unit provided in the exemplary embodiment of this application, showing the spacer member abutting against the high-voltage winding; Figure 15 This is a schematic diagram of the structure of the annular support unit provided in the exemplary embodiment of this application, showing the spacer member abutting against the low-voltage winding; Figure 16 This is a schematic diagram of the structure of the first support bar disposed on the first insulating support ring according to an exemplary embodiment of this application; Figure 17 This is a schematic diagram of the structure of the second support bar disposed on the second insulating support ring according to an exemplary embodiment of this application; Figure 18This is a schematic diagram of the structure of the second insulating support bar abutting against the low-voltage winding provided in an exemplary embodiment of this application, mainly showing the abutting structure of the first support section and the low-voltage winding; Figure 19 This is a schematic diagram of the structure of the second insulating support bar abutting against the low-voltage winding provided in an exemplary embodiment of this application, mainly showing that there is a gap between the second support section and the low-voltage winding; Figure 20 This is a schematic diagram of the structure of multiple coaxially arranged annular support units provided in an exemplary embodiment of this application; Figure 21 In the exemplary embodiment of this application, the second insulating support ring is disposed on the outer periphery of the first insulating support ring; Figure 22 This is a schematic diagram of the structure provided in an exemplary embodiment of this application, showing the first insulating support ring disposed on the outer periphery of the second insulating support ring; Figure 23 This is a schematic diagram of the structure of two first insulating support rings arranged adjacent to each other in an exemplary embodiment of this application; Figure 24 This is a schematic diagram of the structure of two second insulating support rings arranged adjacent to each other in an exemplary embodiment of this application.

[0030] Explanation of reference numerals in the attached figures: 100. Enclosure; 101. Low-voltage bushing; 102. High-voltage bushing; 103. Insulating liquid; 104. Heat dissipation structure; 1041. Heat sink; 1042. Heat dissipation channel; 200. Transformer body; 210. Core post; 211. Iron yoke; 220. High-voltage winding; 221. First winding layer; 222. First connection terminal; 223. Second connection terminal; 230. Low-voltage winding; 231. Second winding layer; 232. Pancake segment; 2321. First wire layer; 233. Cylindrical segment; 2331. Cylindrical sub-segment; 2332. Second wire layer; 2301. Third connection terminal; 2302. Fourth connection terminal; 300. First transformation module; 400. Second Transformation Module; 501. End fastener; 502. Fixing post; 503. Fixing plate; 504. Connecting plate; 601, First lead-out; 602, Second lead-out; 603, Third lead-out; 700, Insulating support structure; 710, First insulating support structure; 720, Second insulating support structure; 730, Third insulating support structure; 701, Annular support unit; 7011, Annular body; 7012, Spacer member; 70111, First insulating support ring; 70121, First support bar; 70112, Second insulating support ring; 70122, Second support bar; 701221, First support segment; 701222, Second support segment; 702a, First fluid channel; 702b, Second fluid channel; 703, Gap; 800. Sealed structure; Y, axial direction; X, radial direction; R, circumferential direction; P, reference plane. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0032] It should be noted that in the description of this application, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," "axial (Y)," "radial (X)," and "circumferential (R)," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. The terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. The term "multiple" refers to two or more.

[0033] In the description of this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0034] In power electronic systems, medium- and high-frequency medium-voltage power converters are the core isolation components of solid-state power converters, and their performance parameters directly determine the overall system's operating efficiency and power density. The operating frequency of medium- and high-frequency medium-voltage power converters is generally above 1 kHz, and their structural design must simultaneously meet medium-voltage insulation requirements and high-frequency electromagnetic operating conditions. To balance power density and insulation reliability, solid insulation or liquid insulation solutions are generally adopted; liquid insulation, with its excellent thermal conductivity and heat dissipation capabilities, is more widely used in large-capacity medium- and high-frequency medium-voltage transformer equipment. Due to the influence of the equipment's turns ratio design, the low-voltage side output current amplitude of this type of power converter is large, placing higher demands on the winding arrangement structure and conductor material selection.

[0035] Existing oil-immersed power frequency converters mostly adopt a structure in which the magnetic core, low-voltage winding, and high-voltage winding are arranged from the inside out. The magnetic core and low-voltage winding are located on the low-potential side, while the high-voltage winding is arranged on the high-potential side. The high-voltage lead and low-voltage lead pass through the housing through insulating sleeves and are then connected to the external electrical circuit.

[0036] However, compared to power frequency power converters, large-capacity medium- and high-frequency medium-voltage power converters operate at significantly higher frequencies (typically 1kHz-20kHz, or even higher). On one hand, the eddy current and hysteresis losses of magnetic core materials (such as silicon steel sheets) increase dramatically at high frequencies, necessitating the use of new low-loss magnetic core materials such as ferrite, amorphous alloys, or nanocrystalline alloys. Simultaneously, the winding conductors experience AC losses due to the skin effect and proximity effect, requiring special winding processes such as Litz wire to suppress eddy current losses.

[0037] On the other hand, high-frequency magnetic fields generate additional stray losses on surrounding metal structural components (such as the inner wall of the enclosure, clamps, and fixing bolts). The high-frequency alternating magnetic field induces eddy currents in the metal components, leading to localized heating, which reduces system efficiency and may cause localized overheating or even insulation failure. Although most stray losses can be improved by increasing the distance between the metal structural components and the windings (essentially keeping the metal components away from the high-frequency, strong magnetic field region), this increases the size of the power conversion device and reduces power density, contradicting the miniaturization requirements of the system.

[0038] In applications requiring high transformer ratios and high current output, the design of the low-voltage side lead-out lines becomes a bottleneck. Low-voltage side windings typically need to carry hundreds or even thousands of amperes of current, and this is high-frequency alternating current. To extract the power from the low-voltage side to the outside of the enclosure, positive and negative lead-out cables or copper busbars must pass through the enclosure. Even if the lead-out lines themselves employ a low-loss Litz wire structure, the unavoidable high-frequency strong magnetic field around them will still electromagnetically couple with the metal enclosure cover or lead-out flange, generating significant eddy currents on the enclosure and causing a sharp rise in localized temperature. High temperatures not only accelerate the aging of the insulating medium but also reduce the service life of bushings and seals, and in severe cases, can lead to insulation breakdown or oil leakage, reducing equipment operating efficiency and safety.

[0039] In view of this, this application provides a power conversion device to solve the technical problems of high eddy current loss, local overheating of the enclosure, and low system efficiency caused by high frequency and high current lead wires.

[0040] Please see Figures 1 to 3 This application provides a power conversion device. This power conversion device is suitable for medium-to-high frequency, medium-voltage, and high-current power conversion scenarios, such as serving as an isolation stage in a solid-state transformer (SST).

[0041] Please see Figure 1 and Figure 2 The power conversion device includes a housing 100, a transformer body 200, a first conversion module 300, and a second conversion module 400. At least one surface of the housing 100 is provided with a low-voltage bushing 101 and a high-voltage bushing 102. The transformer body 200 is disposed within the housing 100 and includes a core 210, a high-voltage winding 220, and a low-voltage winding 230. The high-voltage winding 220 is sleeved on the outer periphery of the core 210 and insulated from the core 210 in the radial direction X. The low-voltage winding 230... The high-voltage winding 220 is sleeved on the outer periphery of the high-voltage winding 220 and insulated from the high-voltage winding 220 in the radial direction X; the first conversion module 300 is disposed inside the housing 100. The first conversion module 300 has an input side and an output side. The input side of the first conversion module 300 is electrically connected to the low-voltage winding 230, and the output side of the first conversion module 300 is electrically connected to the low-voltage bushing 101. The voltage frequency of the input side of the first conversion module 300 is higher than the voltage frequency of the output side of the first conversion module 300.

[0042] Therefore, this application sets up a first conversion module 300 inside the enclosure 100. Utilizing the conversion characteristic that the voltage frequency on its input side is higher than that on its output side, it converts the high-frequency AC power of the low-voltage winding 230 into low-frequency AC power (less than 1kHz) or DC power inside the enclosure 100 before leading it out through the low-voltage bushing 101. This eliminates the need for high-frequency leads to pass through the enclosure 100, thus solving the problem of eddy current losses caused by the high-frequency magnetic field of the leads on the enclosure 100, improving the overheating risk of the enclosure 100, and increasing the overall efficiency. It also eliminates the need to increase the spacing between the winding structure and the metal parts of the enclosure 100, facilitating a compact arrangement of the power conversion device and increasing power density. At the same time, the low-voltage bushing 101 only transmits low-frequency AC / DC power, reducing the difficulty of bushing insulation design. The conversion module, placed inside the enclosure, can also rely on the internal medium of the enclosure 100 for heat dissipation, improving the reliability of equipment operation.

[0043] Please see Figure 1 The enclosure 100 serves as the outer casing of the power conversion device, typically welded from a metallic material (such as steel plate), possessing sufficient mechanical strength to support internal components and withstand certain internal pressures. At least one surface of the enclosure 100 (e.g., the top or side surface) is provided with a low-voltage bushing 101 and a high-voltage bushing 102. The low-voltage bushing 101 and high-voltage bushing 102 are used to lead the internal electrical wiring of the enclosure 100 to the outside, while ensuring insulation and sealing of the enclosure 100. The low-voltage bushing 101 is used to extract low-frequency AC or DC power from the output side of the first conversion module 300, and the high-voltage bushing 102 is used to extract high-voltage power from the high-voltage winding 220. The specific number of low-voltage bushings 101 and high-voltage bushings 102 is determined according to circuit requirements; for example, two bushings are required for single-phase input / output, and three or four bushings are required for three-phase.

[0044] The interior of the enclosure 100 can be filled with an insulating liquid 103, such as mineral oil, natural ester insulating oil (vegetable oil), silicone oil, or other synthetic ester insulating liquid. The insulating liquid 103 serves a dual purpose of insulation and heat dissipation.

[0045] Please see Figure 2 The core post 210 is disposed within the housing 100. The core post 210 is part of the magnetic core and is typically made of a soft magnetic material with low high-frequency loss characteristics. In mid-to-high frequency applications (e.g., 1kHz~100kHz), to effectively suppress hysteresis loss and eddy current loss, the core post 210 can be made of ferrite, amorphous alloy, or nanocrystalline alloy strip wound or stacked. Although Figure 2 Only one core post 210 is shown in the illustration, but the scheme of this application is also applicable to multi-post (such as two-post, three-post, or four-post) power conversion devices, and each core post 210 can be independently equipped with a winding structure. The cross-section of the core post 210 can be rectangular, circular, or stepped to optimize window utilization.

[0046] The transformer body 200 also includes two iron yokes 211, which are respectively connected to the two ends of the core column 210 and together with the core column 210 form a closed magnetic circuit.

[0047] The high-voltage winding 220 is used to receive medium-voltage AC power, such as 3.3kV, 6.6kV, 10kV, or 35kV. Due to the high voltage and relatively small current on the high-voltage side, the high-voltage winding 220 can adopt a cylindrical winding structure.

[0048] Please see Figure 2 and Figure 4 The power conversion device also includes an insulating support structure 700, which is arranged radially between the core column 210 and the high-voltage winding 220 and between the high-voltage winding 220 and the low-voltage winding 230.

[0049] This application achieves stable and uniform insulation gaps between the high-voltage winding 220 and the low-voltage winding 230 by coaxially nesting them from the inside out and arranging insulation support structures 700 at radial X intervals. This allows the insulating liquid 103 to flow within the insulation gaps. The high-voltage winding 220's inlet and outlet lines are led out on the same side, while the low-voltage winding 230's inlet and outlet lines are externally located. This simplifies wiring, facilitates parallel connection, and ensures a uniform electric field, thereby improving the current carrying capacity, operating efficiency, and power density of the power conversion device while ensuring medium-voltage insulation safety.

[0050] The high-voltage winding 220 includes multiple first winding layers 221 arranged coaxially along the radial direction X, and the multiple first winding layers 221 are electrically connected to each other. Each first winding layer 221 is formed by winding multiple turns of first coil layer by layer along the axial direction Y; wherein, the insulating support structure 700 is also arranged in the radial direction X between any two adjacent first winding layers 221.

[0051] Specifically, the multiple first winding layers 221 can be electrically connected by series or parallel connection. Each first winding layer 221 can be formed by tightly winding a continuous Litz wire layer by layer along the axial direction Y, similar to a spiral structure. Figure 4 An exemplary structure with two first winding layers 221 is shown. An insulating support structure 700 may be provided between adjacent first winding layers 221 to provide insulation and aid in heat dissipation.

[0052] Please see Figure 4 In the case where at least two adjacent first winding layers 221 are connected to each other, the innermost first winding layer 221 is provided with a first connection end 222, and the outermost first winding layer 221 is provided with a second connection end 223.

[0053] Specifically, the first connection end 222 and the second connection end 223 of the high-voltage winding 220 are both located at the same end (e.g., the upper end) along the axial direction Y of the power conversion device. This is to facilitate subsequent lead-out and insulation layout. In this embodiment, please refer to... Figure 5 , Figure 5 The diagram illustrates that the high-voltage winding 220 has a structure with two first winding layers, wherein Figure 5 The direction indicated by the middle arrow is the winding direction of the high-voltage winding 220. The starting end of the first winding layer 221 of the innermost loop (i.e., closest to the core post 210) serves as the first connection end 222, and the ending end of the first winding layer 221 of the outermost loop (i.e., closest to the low-voltage winding 230) serves as the second connection end 223. When the high-voltage winding 220 needs to be split into multiple high-voltage sub-windings connected in series or parallel, all the multiple connection ends of the high-voltage winding 220 are led to the same end. The first connection end 222 is the input end, and the second connection end 223 is the output end. Conversely, the first connection end 222 is the output end, and the second connection end 223 is the input end.

[0054] The first connection end 222 and the second connection end 223 are both located on the same side of the high voltage winding 220, wherein the first connection end 222 and the second connection end 223 are close to each other and insulated from each other.

[0055] Therefore, by setting the first connection end 222 and the second connection end 223 on the same side, this application can shorten the layout space of the high voltage winding 220 lead wire, simplify the external wiring layout, reduce the high frequency magnetic field, reduce the eddy current loss and interference of the high voltage winding 220 to the surrounding metal, and at the same time facilitate external circuit connection and insulation covering, improve assembly efficiency and end insulation reliability.

[0056] Please see Figure 6 and Figure 7 The low-voltage winding 230 includes multiple second winding layers 231, which are stacked and coaxially arranged along the axial direction Y. Each second winding layer 231 includes a disc-shaped segment 232 and a cylindrical segment 233 connected along the axial direction Y. The disc-shaped segment 232 includes multiple turns of first wire layer 2321, which are concentrically wound from the outside to the inside along the radial direction X, and the outermost first wire layer 2321 is provided with a third connecting end 2301. The cylindrical segment 233 includes multiple turns of cylindrical sub-segments 2331, which are arranged along the radial direction X and connected to each other. Each cylindrical sub-segment 2331 includes multiple turns of second wire layer 2332 arranged along the axial direction Y, the outermost second wire layer 2332 is provided with a fourth connecting end 2302, and the innermost first wire layer 2321 and the second wire layer 2332 of the innermost cylindrical sub-segment 2331 are connected.

[0057] Specifically, the low-voltage winding 230 is used to output a transformed low voltage and high current, for example, a voltage level of 400V to 1500V and a current level of several thousand amperes. To carry such a large current, the low-voltage winding 230 includes multiple second winding layers 231 stacked along the axial Y-axis. Each second winding layer 231 is essentially an independent low-voltage coil. Multiple second winding layers 231 can be connected in parallel via external copper busbars or flexible connections. To facilitate parallel connection, the third connection terminal 2301 and the fourth connection terminal 2302 of each second winding layer 231 are led out to the outer peripheral surface of the second winding layer 231 itself. For a second winding layer 231, the third connection terminal 2301 and the fourth connection terminal 2302 of the second winding layer 231 are located on the same side of the low-voltage winding 230 to facilitate a one-time connection using a U-shaped or flat busbar.

[0058] Please see Figure 8 and Figure 9 , Figure 8 and Figure 9 The specific structure of a second winding layer 231 is shown in detail. Figure 8 The illustrated embodiment shows that the low-voltage winding 230 has a two-layer structure in the radial direction X and a three-layer arrangement in the axial direction Y. Figure 9 The embodiment shown illustrates that the low-voltage winding 230 has a two-layer structure in the radial direction X and a two-layer arrangement in the axial direction Y.

[0059] To arrange more effective conductors within a limited axial Y-height and ensure that both the incoming and outgoing ends are on the outside, this embodiment employs a combined pancake and cylindrical winding method. Specifically, a second winding layer 231 includes a pancake segment 232 and a cylindrical segment 233 connected along the axial Y. The pancake segment 232 is located on top, and the cylindrical segment 233 is located on the bottom. The positions of the pancake segment 232 and the cylindrical segment 233 can be interchanged.

[0060] The disc-shaped segment 232 is formed by a multi-segment staggered winding method, consisting of multiple turns of the first thread layer 2321 concentrically wound from the outside to the inside along the radial direction X. The free end of the outermost first thread layer 2321 is the third connecting end 2301. The end of the innermost first thread layer 2321 has a connection point that connects to the cylindrical segment 233.

[0061] The cylindrical segment 233 comprises multiple cylindrical sub-segments 2331, which are arranged radially X and connected in series. Each cylindrical sub-segment 2331 is itself a multi-turn second layer 2332 arranged axially Y, similar to a cylindrical winding. The end of the outermost second layer 2332 of the outermost cylindrical sub-segment 2331 is the fourth connection end 2302. The beginning of the innermost second layer 2332 of the innermost cylindrical sub-segment 2331 is connected to the end of the innermost first layer 2321 of the disc segment 232.

[0062] Specifically, such as Figure 8 and 9 As shown, the first turn is located on the outer periphery of the second turn, and the two are arranged in the same layer radially (X), together forming the disc-shaped segment 232 of the low-voltage winding 230. The third and fourth turns are located on the same side of the second turn, and the second, third, and fourth turns are arranged alternately along the axial direction (Y) and are arranged in the same layer. The fifth turn is located on the outer periphery of the fourth turn, and the two are arranged in the same layer radially (X); the sixth turn is located on the outer periphery of the third turn, and the two are arranged in the same layer radially (X); the third, fourth, fifth, and sixth turns together form the cylindrical segment 233 of the low-voltage winding 230. In this embodiment, the first, fifth, and sixth turns together form the outer layer structure of the low-voltage winding 230, and the second, third, and fourth turns together form the inner layer structure of the low-voltage winding 230. Figure 8 The arrow connecting to the first turn is the first connection end 222, and the arrow connecting to the sixth turn is the second connection end 223.

[0063] During winding, the second turn 2 is first wound to form the inner layer structure of the disc segment 232. Then, the first turn is wound around the outer periphery of the second turn 2 to form the outer layer structure of the disc segment 232. Subsequently, at the other end of the second turn, along the axial direction Y, the third and fourth turns, which are approximately coaxial with the second turn, are wound sequentially to form the inner layer structure of the cylindrical segment 233. Finally, on the outer periphery of the inner layer structure of the cylindrical segment 233, the fifth and sixth turns, which are approximately coaxial with the first turn, are wound sequentially to form the outer layer structure of the cylindrical segment 233. The embodiments of this application include, but are not limited to, the above winding method, and will not be described in detail here.

[0064] Therefore, the low-voltage winding 230 of this application combines the disc-shaped segment 232 with the cylindrical segment 233, giving the low-voltage winding 230 the dual advantages of convenient outer layer output of the disc-shaped winding and simple winding process of the cylindrical winding. For a second winding layer 231, current can flow in from the third connection terminal 2301 located on the outer peripheral surface, sequentially through the disc-shaped segment 232 (from outside to inside), the cylindrical segment 233 (from inside to outside), and finally out from the fourth connection terminal 2302, which is also located on the outer peripheral surface and adjacent to the third connection terminal 2301. In this way, the input and output terminals of the entire second winding layer 231 are on the outside, and the structure can be flexibly expanded by adjusting the number of segments, layers, and arrangement. It can adapt to the application scenarios of medium- and high-frequency medium-voltage power conversion devices with different capacities, frequencies, and voltage levels, improving the versatility and applicability of the low-voltage winding 230 structure.

[0065] Please see Figure 7 The first connecting end 222 and the second connecting end 223 have a first orthographic projection on the reference plane P, and the third connecting end 2301 and the fourth connecting end 2302 have a second orthographic projection on the reference plane P. The first orthographic projection does not coincide with the second orthographic projection in the radial direction X, wherein the reference plane P is perpendicular to the axial direction Y.

[0066] In one example, the first connecting end 222 and the second connecting end 223 are arranged vertically along the axial direction Y, such that their orthographic projections on the reference plane P overlap. In another example, the first connecting end 222 and the second connecting end 223 are spaced apart along the circumferential direction R of the high-voltage winding 220, such that their orthographic projections on the reference plane P do not overlap.

[0067] In one example, the third connection terminal 2301 and the fourth connection terminal 2302 are arranged vertically in the axial direction Y, so that their orthographic projections on the reference plane P overlap. In another example, the third connection terminal 2301 and the fourth connection terminal 2302 are spaced apart in the circumferential direction R of the low-voltage winding 230, so that their orthographic projections on the reference plane P do not overlap.

[0068] In some embodiments, the first orthographic projection does not coincide with the second orthographic projection in the radial X direction, which can avoid projection overlap, insufficient electrical spacing and insufficient creepage distance between high and low voltage leads, effectively increase the insulation distance between high and low voltage terminals, reduce end electric field cross interference, suppress partial discharge, surface discharge and short circuit risk between terminals at different potentials, and improve the insulation safety and operational reliability of power conversion devices under medium-frequency and medium-voltage conditions.

[0069] In one example, the first orthographic projection and the second orthographic projection are located on both sides of the high-voltage winding 220 or the low-voltage winding 230 in the radial direction X, respectively. This allows the connection terminals of the high-voltage winding 220 and the low-voltage winding 230 to be located on different sides. This ensures that the electrical spacing and creepage distance between each terminal meet the insulation requirements, suppresses partial discharge, and also organizes the lead wire arrangement, simplifies the external wiring, makes the winding end structure symmetrical in terms of force, and improves the overall assembly convenience and structural stability.

[0070] In some embodiments, the number of high-voltage windings 220 is one or more, the number of low-voltage windings 230 is multiple, and the number of low-voltage windings 230 is greater than the number of high-voltage windings 220.

[0071] It is understood that the high-voltage winding 220 can have an auxiliary terminal led out from between the first connecting end 222 and the second connecting end 223. That is, the high-voltage winding 220 may include the first connecting end 222, the second connecting end 223, and at least one auxiliary terminal. This auxiliary terminal is an additional terminal led out from a specified number of turns in the middle of the high-voltage winding 220 between the two main leads (the first connecting end 222 and the second connecting end 223) of the same high-voltage winding 220, and is not led out from the midpoint of the winding's geometric end face. The auxiliary terminal can be used for voltage regulation or matching of full-wave rectifier circuits. In this embodiment, the number of outgoing lines of the high-voltage winding 220 (i.e., the sum of the number of the first connection terminal 222, the second connection terminal 223, and the auxiliary connection terminal) is much smaller than the number of outgoing lines of the low-voltage winding 230 (i.e., the sum of multiple third connection terminals 2301 and multiple fourth connection terminals 2302), and the incoming and outgoing lines are located at the ends of the winding structure. Different column high-voltage windings 220 can also be connected in series or in parallel according to system requirements to adapt to different voltage levels and power demands. This application divides the low-voltage winding 230 into multiple sets of second winding layers 231, i.e., coils, each coil being wound using a multi-segment staggered winding method. This allows for flexible parallel connection of multiple sets of low-voltage coils even when the number of low-voltage windings 230 exceeds that of the high-voltage winding 220, thereby improving the low-voltage side current carrying capacity and power expansion capability.

[0072] Therefore, this application provides a power conversion device that adjusts the winding arrangement sequence to core post 210, high-voltage winding 220, and low-voltage winding 230, so that the low-voltage winding 230 is located on the outermost side. The input and output terminals of the low-voltage winding 230 (i.e., the third connection terminal 2301 and the fourth connection terminal 2302) are located on its outer circumference, facilitating multiple sets of parallel connections directly or indirectly from the outside. Combined with the use of a multi-set coil structure (i.e., multiple second winding layers 231), each coil itself leads its input and output terminals to the outside through multiple staggered windings, thereby enabling multiple low-voltage coils to be flexibly connected in parallel through external copper busbars or lead posts, solving the problem of difficult parallel connection caused by the middle-output lead of the low-voltage winding 230 in traditional structures. Therefore, even though the current carrying capacity of a single high-frequency Litz wire is limited due to process constraints, by splitting the low-voltage winding 230 into multiple parallel coils, the equivalent current carrying capacity of the low-voltage winding 230 can be multiplied, and can be easily expanded to an equivalent total number of more than 4,000 strands, adapting to high current conditions, while retaining the inherent advantage of low eddy current loss of Litz wire at medium and high frequencies.

[0073] Both the first winding layer 221 and the second winding layer 231 are made of Litz wire, which is composed of multiple single-strand enameled wires twisted together, with the diameter of each single-strand enameled wire ranging from 0.05mm to 0.2mm. Specifically, the first winding layer 221 is made of high-frequency Litz wire, which is formed by multiple single-strand enameled wires twisted together in multiple stages. The number of twisting stages can be flexibly set according to the operating frequency and the current requirements of the high-voltage winding 220, and generally a two-stage or three-stage twisting structure is adopted.

[0074] Those skilled in the art will understand that the above-mentioned range of single-strand enameled wire diameters is merely an exemplary specific value. In practical applications, the wire diameter can be flexibly selected and adjusted within the range of 0.05mm to 0.2mm, depending on the operating frequency, voltage level, and loss requirements of the power conversion device. For example, 0.05mm, 0.08mm, 0.10mm, 0.12mm, 0.15mm, 0.18mm, or 0.20mm can all be selected, all of which fall within the scope of the protection concept of this application.

[0075] Please see Figure 1The first conversion module 300 is housed within the enclosure 100. The first conversion module 300 has an input side and an output side. The input side of the conversion module is electrically connected to the low-voltage winding 230, and the output side of the first conversion module 300 is electrically connected to the low-voltage bushing 101. The voltage frequency on the input side of the first conversion module 300 is higher than the voltage frequency on the output side of the conversion module. That is, the conversion module functions to reduce the frequency. Specifically, when the power conversion device operates at medium to high frequencies (e.g., 1kHz to 100kHz), the low-voltage winding 230 outputs a 10kHz high-frequency AC current. The first conversion module 300 can be an uncontrolled rectifier bridge (composed of diodes) that rectifies 10kHz AC power into DC power (0Hz) for output; or the first conversion module 300 can be a two-stage structure of rectification and inversion, first rectifying to DC power and then inverting to 50Hz or 60Hz power frequency AC power for output; or the first conversion module 300 can also be a matrix conversion module or other direct AC-AC conversion circuit that directly converts 10kHz AC power into 400Hz or lower frequency AC power. Regardless of the specific implementation, it is acceptable as long as the input voltage frequency is higher than the output voltage frequency.

[0076] Figure 10 This illustrates a half-bridge topology, primarily showcasing the structure of a half-bridge submodule. For example... Figure 10 As shown, the half-bridge submodule includes a first switching device S1, a second switching device S2, and an energy storage capacitor C. Both S1 and S2 are connected in reverse parallel with freewheeling diodes. The emitter of S1 is connected to the collector of S2 to form the positive input side of the submodule. The collector of S1 is connected to the positive terminal of the energy storage capacitor C, and the emitter of S2 is connected to the negative terminal of the energy storage capacitor C. The energy storage capacitor C is connected across the two ends of S1 and S2. The emitter of S2 leads out to the negative input side of the submodule. The submodule input side is supplied with a submodule voltage Usm and an input current Ism.

[0077] Figure 10 The illustrated embodiment achieves level switching by controlling the on / off state of S1 and S2: when S1 is on and S2 is off, the submodule outputs the rated voltage of the energy storage capacitor; when S1 is off and S2 is on, the submodule outputs zero voltage. This submodule can only output two levels: zero voltage and positive capacitor voltage. It uses fewer components, has simple control logic, and has low cost and conduction loss, but it cannot output negative voltage, and its bidirectional power flow capability is limited. It is suitable for unipolar voltage conversion conditions.

[0078] Figure 11 This illustrates a full-bridge topology, primarily showcasing the structure of a full-bridge submodule. For example... Figure 11As shown, the full-bridge submodule consists of a first switching device S1, a second switching device S2, a third switching device S3, a fourth switching device S4, and an energy storage capacitor C. Each switching device is equipped with a reverse parallel freewheeling diode. S1 and S2 are connected in series to form the left bridge arm, and their midpoint is the positive input terminal of the submodule. S3 and S4 are connected in series to form the right bridge arm. The positive terminal of the energy storage capacitor C is connected to the collectors of S1 and S3, and the negative terminal of the energy storage capacitor C is connected to the emitters of S2 and S4, respectively. The lower ends of the left and right bridge arms are connected together to form the negative input terminal of the submodule. The submodule input side is connected to the submodule voltage Usm and the input current Ism. The upper and lower midpoints of the left and right bridge arms constitute the submodule voltage output side.

[0079] Figure 11 The illustrated embodiment relies on the coordinated switching of four switching transistors to achieve three types of output levels in the submodule: positive capacitor voltage when S1 and S4 are on, negative capacitor voltage when S2 and S3 are on, and zero voltage when the switches on the same side are on simultaneously. This structure can output positive, zero, and negative levels, enabling bidirectional power transmission. After multiple modules are cascaded, it is easy to modulate and generate alternating medium- and high-frequency voltages, adapting to inverter scenarios from medium-voltage DC to medium- and high-frequency AC. Compared with the half-bridge structure, it uses more power devices, and the device losses and hardware costs are correspondingly increased.

[0080] Please see Figure 12 , Figure 12 The power conversion device topology diagram provided in the embodiments of this application mainly illustrates the conversion from medium voltage direct current (MVDC) to low voltage direct current (LVDC). For example... Figure 12 As shown, the power conversion device includes a first conversion module 300, a transformer body 200, and a second conversion module 400. The transformer body 200 and the first conversion module 300 provided in this application are integrated inside the housing 100 of the power conversion device. In some other topologies, the power conversion device of this application can also serve as an isolation stage, and the function of the first conversion module 300 can be integrated on the low-voltage side.

[0081] Figure 12 In the middle, the DC input side is connected to the input voltage Vi, and the positive and negative buses of Vi are connected in parallel with supporting capacitors C11 and C12; the second conversion module 400 is divided into an upper series sub-module branch and a lower series sub-module branch. The upper series branch is formed by SM11, SM12 to SM1N connected in series, and the upper branch ends with a filter inductor L11 connected in series; the lower series branch is formed by SM21, SM22 to SM2N connected in series, and the lower branch ends with a filter inductor L12 connected in series; the output sides of inductors L11 and L12 are connected to the high voltage winding 220 of the transformer body 200 through the DC blocking capacitor C21.

[0082] Support capacitors C11 and C12 are used to stabilize the input bus voltage and filter out voltage ripple. Each submodule uses the half-bridge or full-bridge topology mentioned above. By controlling the switching devices inside the submodule, the input DC voltage Vi is modulated into a medium-to-high frequency AC voltage. L11 and L12 serve to limit current and smooth the AC output waveform. C21 blocks the DC component to avoid DC bias causing core saturation of the power conversion device. Only the medium-to-high frequency AC power is fed into the high-voltage winding 220 of the power conversion device.

[0083] like Figure 11 and Figure 12 As shown, the high-voltage winding 220 includes at least one high-voltage sub-winding, and the low-voltage winding 230 includes multiple low-voltage sub-windings. Figure 12 The diagram illustrates that the high-voltage winding 220 includes one high-voltage sub-winding L21, and the low-voltage winding 230 includes three sets of low-voltage sub-windings L31, L32, and L33. The high-voltage sub-winding L21 receives the medium-to-high frequency AC power output from the first conversion module 300, and achieves electromagnetic coupling through the magnetic conduction of the core 210, inducing high-frequency AC power of the same frequency in each set of low-voltage sub-windings L31, L32, and L33. Each set of low-voltage windings L31, L32, and L33 is independently led out and connected one-to-one to the corresponding first conversion module 300 within the housing 100.

[0084] The first conversion module 300 includes multiple sets of rectifier and filter units corresponding to multiple sets of low-voltage sub-windings. Each set of rectifier and filter units consists of a rectifier bridge composed of four diodes and a filter capacitor. The low-voltage sub-winding L31 is connected to the input side of the rectifier bridge composed of D11, D12, D13, and D14, and outputs rectified output and is connected in parallel with the filter capacitor C31. The low-voltage sub-winding L32 corresponds to D21, D22, D23, D24 and C32. The low-voltage sub-winding L33 corresponds to D31, D32, D33, D34 and C33. The DC output sides of all rectifier and filter units are connected in parallel to form the overall output voltage Vo. The combined DC power is led out to the outside of the housing 100 through the low-voltage bushing 101 on the housing 100.

[0085] It should be noted that the input side of the first conversion module 300 is the input side of the rectifier bridge (the connection node between the rectifier filter unit and the low-voltage winding), and the output side of the first conversion module 300 is the DC output side of the rectifier filter unit.

[0086] Each rectifier bridge rectifies the high-frequency AC power input from the second converter module 400 to the low-voltage sub-winding into DC power, with a matching capacitor filtering out DC ripple. The side of the first converter module 300 connected to the low-voltage winding 230 is the high-frequency side, and the output side connected to the low-voltage bushing 101 is the low-frequency DC side. This satisfies the requirement that the voltage frequency on the input side of the first converter module 300 is higher than the voltage frequency on the output side. All high-frequency power is rectified and converted inside the housing 100, with only DC power exiting the housing 100, thus avoiding eddy current heat loss in the housing 100 caused by high-frequency leads penetrating the housing 100. Multiple sets of low-voltage sub-winding rectified outputs are connected in parallel to achieve even distribution of high-current output on the low-voltage side, improving the power density and heat dissipation performance of the power conversion device.

[0087] This application addresses the issue of high-frequency, high-current transmission paths by placing the low-voltage winding 230 around the high-voltage winding 220 and placing a first conversion module 300 near the low-voltage winding 230. This significantly shortens the path (e.g., by a few centimeters) of the high-frequency, high-current transmission path. The shorter path reduces the lead loop area, thereby decreasing lead losses and the eddy current effects of the high-frequency magnetic field on the enclosure 100 and metal components. Simultaneously, the first conversion module 300 performs frequency conversion, converting the high-frequency electricity into low-frequency AC or DC electricity before it is led out through the low-voltage bushing 101. The low-frequency AC / DC magnetic field is less likely to induce eddy currents in metal components such as the enclosure 100, thus solving the problem of eddy currents and heat generation in the leads of the enclosure 100 (e.g., the cover).

[0088] In some embodiments, such as Figure 1 As shown, the housing 100 is filled with insulating liquid 103, and the first conversion module 300 is also immersed in the insulating liquid 103. This complete immersion method provides optimal heat dissipation. The power semiconductor devices (such as diodes, MOSFETs, IGBTs, etc.) in the first conversion module 300 generate a large amount of heat during operation. By directly immersing these components in the insulating oil, the heat can be quickly carried away by the oil flow and then dissipated through the walls of the housing 100 or external heat sinks. Compared to traditional air cooling, oil has a higher specific heat capacity and thermal conductivity, significantly improving cooling efficiency. Furthermore, the insulating oil also has excellent electrical insulation properties, preventing creepage or short circuits within the conversion module.

[0089] The component packaging material of the first conversion module 300 needs to be chemically compatible with the insulating liquid 103, meaning that long-term contact will not cause adverse reactions such as swelling, corrosion, dissolution, or a decrease in insulation performance, thus adapting to immersion environments. For example, oil-resistant epoxy resin can be used as the molding material, polytetrafluoroethylene (PTFE) or cross-linked polyethylene (XLPE) can be used as the conductor insulation layer, and ceramic substrates or surface FR-4 PCBs can be used. FR-4 PCB refers to a printed circuit board made using FR-4 material as the substrate; FR-4 stands for Flame Retardant 4.

[0090] Therefore, this application immerses the first conversion module 300 in the insulating liquid 103, relying on the insulating medium to achieve efficient heat dissipation and electrical insulation, delay device aging, and further improve the operational reliability of the power conversion device.

[0091] Please see Figure 1 The power conversion device also includes two end fixing members 501 and multiple fixing posts 502. The two end fixing members 501 are respectively disposed at both ends of the transformer body 200 in the axial direction Y, and each fixing post 502 connects the two end fixing members 501. The first conversion module 300 is disposed between the low voltage winding 230 and the inner wall of the housing 100 and is connected to the two end fixing members 501.

[0092] Specifically, two end fasteners 501 are respectively disposed at the upper and lower ends of the core column 210 in the axial direction Y. The end fasteners 501 are typically metal or insulating pressure plates, used to clamp and fix the core column 210, high-voltage winding 220, and low-voltage winding 230 in the axial direction Y. Each fixing post 502 connects two end fasteners 501. The fixing post 502 can be a metal screw or an insulating screw, passing through the two end fasteners 501 and locked with a nut, thereby securing the entire high-voltage winding 220, low-voltage winding 230, and magnetic core assembly into a single unit. Multiple fixing posts 502 can be arranged circumferentially, for example, three or four.

[0093] Please see Figure 1In this embodiment, the first conversion module 300 is disposed between the low-voltage winding 230 and the inner wall of the housing 100, and is connected to two end fixing members 501. Specifically, the first conversion module 300 can be made into a planar plate structure, which can be arranged as a single first conversion module 300 or as multiple plate-type first conversion modules 300 arranged in segments along the outer periphery of the low-voltage winding 230. All first conversion modules 300 are installed in the annular gap 703 between the outer periphery of the low-voltage winding 230 and the inner wall of the housing 100. The housing or mounting bracket of the first conversion module 300 can be directly fixed to the upper end fixing member 501 and the lower end fixing member 501 by bolts, clips, etc. This installation method utilizes the end fixing member 501 as a load-bearing structure, eliminating the need for additional support structures specifically designed for the conversion module, which helps to simplify the design and reduce the size.

[0094] Please see Figure 1 The power conversion device also includes a fixing plate 503 and a connecting plate 504; the fixing plate 503 is located between the low-voltage winding 230, the first conversion module 300 and the inner wall of the housing 100, and the two ends of the fixing plate 503 along the axial direction Y are respectively connected to the end fixing member 501 through the connecting plate 504.

[0095] Specifically, the fixing plate 503 can be a flat plate extending along the axial direction Y, or an arc-shaped plate surrounding the low-voltage winding 230. The converter module is mounted on the fixing plate 503. The connecting plate 504 connects the upper and lower ends of the fixing plate 503 to the upper and lower end fixing members 501, respectively. This structure allows the converter module to be pre-assembled onto the fixing plate 503 to form a sub-assembly, and then inserted as a whole into the gap 703 between the winding and the housing 100, and then fixed to the main structure by the connecting plate 504, which facilitates manufacturing and maintenance. The fixing plate 503 can also serve as a magnetic shield or an electrical shield to reduce magnetic field interference to the converter module. In addition, the fixing plate 503 and the connecting plate 504 can be made of insulating materials (such as epoxy glass cloth) to avoid the formation of loop currents and eddy current heating.

[0096] In some embodiments, if certain components of the first conversion module 300 are incompatible with the insulating liquid 103, or if for other design considerations it is undesirable for the conversion module to directly contact the insulating medium, a method such as Figure 13 The structure shown.

[0097] Please see Figure 13The power conversion device also includes a sealing structure 800. Both the sealing structure 800 and the first conversion module 300 are mounted on the inner wall of the housing 100. The sealing structure 800 covers the outer periphery of the first conversion module 300, forming a sealed cavity that isolates the first conversion module 300 from the insulating liquid 103. The sealing structure 800 can be a metal box or an oil-resistant plastic box, fixed to the inner wall of the housing 100 via flanges, sealing rings, and screws, or welded. The interior of the sealing structure 800 can be filled with dry air or nitrogen, or with thermally conductive silicone grease or thermally conductive potting compound to facilitate heat conduction. The heat generated by the conversion module is transferred through the wall of the sealing structure 800 to the external insulating liquid 103, and then dissipated through the housing 100. This structure balances insulation and cooling with material compatibility.

[0098] Please see Figure 1 , Figure 12 and Figure 13 The input side of the first conversion module 300 is electrically connected to the low-voltage winding 230 through the first lead 601, the output side of the first conversion module 300 is electrically connected to the low-voltage bushing 101 through the second lead 602, and the high-voltage winding 220 is electrically connected to the high-voltage bushing 102 through the third lead 603.

[0099] Specifically, the input side of the first conversion module 300 is electrically connected to the low-voltage winding 230 via a first lead 601 (i.e., the connection line between the low-voltage winding 230 and the first conversion module 300). The output side of the first conversion module 300 is electrically connected to the low-voltage bushing 101 via a second lead 602 (i.e., the output line of the first conversion module 300). Simultaneously, the high-voltage winding 220 is electrically connected to the high-voltage bushing 102 via a third lead 603 (high-voltage lead).

[0100] To increase the creepage distance and clearance 703 between the high and low voltages, the connection point of the second lead 602 to the low-voltage bushing 101 is located on one side of the low-voltage winding 230 in the radial direction X, and the connection point of the third lead 603 to the high-voltage bushing 102 is located on the other side of the low-voltage winding 230 in the radial direction X. More specifically, the first lead 601 and the second lead 602 are collectively referred to as low-voltage leads. In this embodiment, the connection points of the low-voltage leads to the low-voltage bushing 101 and the high-voltage leads to the high-voltage bushing 102 are respectively located on both sides of the low-voltage winding 230 in the radial direction X. Specifically, if the power conversion device is considered as a cylinder, both the high-voltage and low-voltage leads are led out from the upper part of the cylinder. For example, the high-voltage bushing 102 and the low-voltage bushing 101 are respectively disposed on the left and right sides of the top cover of the housing 100, or they can be correspondingly disposed on the left and right side walls of the housing 100. This partitioning method effectively separates high-voltage and low-voltage areas, reducing electric field distortion and the risk of breakdown. The power conversion device also includes the previously mentioned second conversion module 400, in which... Figure 1 and Figure 13 The structure of the second transformation module 400 is not shown in the diagram. Please refer to [link / reference needed]. Figure 12 The second conversion module 400 is disposed outside the housing 100 and electrically connected to the transformer body 200, wherein the output voltage of the second conversion module 400 is greater than the output voltage of the first conversion module 300.

[0101] Therefore, this application places the second conversion module 400 outside the enclosure 100 and its voltage is higher than that of the first conversion module 300. On the one hand, this allows for the separate arrangement of high and low voltage devices, with external heat dissipation for high voltage devices and oil immersion cooling for low voltage conversion modules, ensuring that heat dissipation does not interfere with each other. On the other hand, it increases the distance between the high voltage circuit and the internal components of the enclosure 100, reducing high voltage electromagnetic interference and insulation hazards. At the same time, the high voltage conversion module does not require opening the enclosure to drain oil during maintenance, making operation and maintenance convenient. It also avoids high voltage heat contamination of the insulating liquid 103 inside the enclosure 100, extending the service life of the insulating liquid 103 and internal components.

[0102] Please see Figure 1 and Figure 13 The power conversion device also includes a heat dissipation structure 104, which is connected to the housing 100.

[0103] Specifically, the enclosure 100 has an opening (not shown), and the heat dissipation structure 104 is installed inside the opening and fixedly connected to the enclosure 100. The heat dissipation structure 104 includes multiple heat sinks 1041, each heat sink 1041 having a heat dissipation channel 1042 communicating with the interior of the enclosure 100. The insulating liquid 103 can directly enter the heat dissipation channel 1042 of the heat dissipation structure 104 and exchange heat with it; heat is transferred outward through the heat dissipation structure 104, and then dissipated into the external environment through air convection and thermal radiation, continuously reducing the temperature of the enclosure 100 and the internal insulating liquid 103, forming a continuous heat exchange cycle. The heat sinks 1041 are hollow corrugated heat sinks 1041, which effectively increases the heat exchange area and enhances the heat dissipation effect.

[0104] In other embodiments, the heat dissipation structure 104 can be a heat sink 1041, fins, etc., to increase the heat exchange area and further improve the heat dissipation efficiency.

[0105] The housing 100 can also be equipped with other components, such as temperature sensors, pressure relief valves, level gauges, sampling valves, cooling pipes, and oil pumps, to achieve circulating cooling of the insulating liquid 103 and further improve heat dissipation efficiency. These components can be configured according to actual needs, and will not be described in detail in this embodiment.

[0106] Please see Figure 2The insulating support structure 700 has multiple components, including at least a first insulating support structure 710 and a second insulating support structure 720. The first insulating support structure 710 is disposed radially X-oriented in the gap between the core post 210 and the high-voltage winding 220. The second insulating support structure 720 is disposed radially X-oriented in the gap between the high-voltage winding 220 and the low-voltage winding 230. Furthermore, when the high-voltage winding 220 has multiple layers of first winding layers 221, a similar insulating support structure 700, namely a third insulating support structure 730, can also be disposed between the layers.

[0107] Please see Figure 14 and Figure 15 The insulating support structure 700 includes an annular support unit 701. The annular support unit 701 includes an annular body 7011 and a plurality of spacers 7012 extending axially along the Y direction disposed on the annular body 7011. The plurality of spacers 7012 are spaced apart along the circumferential direction R of the annular body 7011. The annular support unit 701 abuts against the circumferential surface of the high-voltage winding 220 or the circumferential surface of the low-voltage winding 230 in the radial direction X, thereby defining at least one first fluid channel 702a. In other words, the first fluid channel 702a is formed by the interaction of two adjacent spacers 7012, the annular body 7011, and the winding.

[0108] Figure 14 The diagram illustrates the contact between the annular support unit 701 and the inner circumferential surface of the low-voltage winding 230, thereby defining at least one first fluid channel 702a. Figure 14 The annular support unit 701 is shown to abut against the outer peripheral surface of the high-voltage winding 220 in the radial direction X, thereby defining at least one first fluid channel 702a.

[0109] It should be noted that, Figure 14 The example shown is merely illustrative of a scenario where the insulating support structure is located between the high-voltage winding and the low-voltage winding. In another embodiment, when the insulating support structure is disposed between the core post and the high-voltage winding, the annular support unit abuts against the inner circumferential surface of the high-voltage winding in the radial direction X to define at least one first fluid channel. Alternatively, in an alternative embodiment, the annular support unit abuts against the outer circumferential surface of the core post in the radial direction X, which can also define at least one first fluid channel, and will not be elaborated further here.

[0110] Therefore, the insulating support structure 700 abuts against the circumferential surface of the high-voltage winding 220 or the circumferential surface of the low-voltage winding 230 through the annular support unit 701 with the circumferential R-spacer 7012, thereby achieving winding insulation support, positioning and anti-displacement, and forming a through first fluid channel 702a, balancing heat dissipation and reducing costs.

[0111] During transformer operation, the insulating liquid 103 (transformer oil) filling the tank can flow freely within the first fluid channel 702a. When the winding structure heats up, the oil in the first fluid channel 702a rises due to its decreased density caused by heat, forming natural convection. The hot insulating liquid 103 flows through the heat dissipation structure 104 on the outside of the tank, where its temperature decreases and its density increases, before flowing back downwards, forming a complete circulating oil channel. Alternatively, forced convection can be formed under the drive of an external oil pump, further efficiently removing heat.

[0112] Please see Figure 16 ,exist Figure 16 In the illustrated embodiment, the annular body 7011 of the annular support unit 701 is configured as a first insulating support ring 70111, and the spacer member 7012 includes a plurality of first support bars 70121, which are spaced apart along the circumferential direction R on the first insulating support ring 70111. Figure 14 and Figure 15 As shown, the first support bar 70121 abuts against the circumferential surface of the high-voltage winding 220 or the circumferential surface of the low-voltage winding 230 in the radial direction X. Figure 16 As shown, the shape and size of the cross-section of the first support bar 70121 at any position along the axial Y direction remain consistent. In this way, the first support bar 70121 can stably abut against the high voltage winding 220 or the low voltage winding 230 to achieve uniform insulation support and positioning, form a through-flow first fluid channel 702a for heat dissipation, and ensure that the support bar is subjected to consistent force and flow channel width at all points along the axial Y direction. The winding is subjected to uniform force and there is no temperature difference in the axial Y direction for heat dissipation. At the same time, the processing and forming are simpler and the size control is more convenient.

[0113] Please see Figure 17 , Figure 18 and Figure 19 The annular body 7011 of the annular support unit 701 is configured as a second insulating support ring 70112. The spacer member 7012 includes a plurality of second support bars 70122. The plurality of second support bars 70122 are spaced apart on the second insulating support ring 70112 along the circumferential direction R. The second support bar 70122 includes a first support segment 701221 and two second support segments 701222. The two second support segments 701222 are respectively connected to the two ends of the first support segment 701221 in the axial direction Y. The first support segment 701221 abuts against the circumferential surface of the high voltage winding 220 or the circumferential surface of the low voltage winding 230 in the radial direction X. A gap 703 is provided between the second support segment 701222 and the circumferential surface of the high voltage winding 220 or the circumferential surface of the low voltage winding 230 in the radial direction X.

[0114] It should be noted that, Figure 18 and Figure 19The schematic diagram illustrating the fit between the annular support unit 701 and the low-voltage winding 230 is shown only as an example. Although the fit between the annular support unit 701 and the high-voltage winding 220 or the core column 110 is not shown separately in this embodiment, it is understood that the fit between the annular support unit 701 and the high-voltage winding 220 or the core column 110 is similar to the fit between the annular support unit 701 and the low-voltage winding 230 described above. Those skilled in the art can implement this based on the accompanying drawings and the description, so it will not be described again here.

[0115] Please see Figure 20 The insulating support structure 700 includes a plurality of coaxially arranged annular support units 701. Each annular support unit 701 includes an annular body 7011 and a plurality of spacers 7012 extending axially along the Y direction disposed on the annular body 7011. The plurality of spacers 7012 are spaced apart along the circumferential direction R of the annular body 7011. Specifically, the spacers 7012 of one annular support unit 701 abut against the circumferential surface of the high-voltage winding 220 or the circumferential surface of the low-voltage winding 230 in the radial direction X to define at least one first fluid channel 702a. The spacers 7012 of another annular support unit 701 abut against the annular body 7011 of an adjacent annular support unit 701 to define at least one second fluid channel 702b. In other words, the first fluid channel 702a is formed by the interaction of two adjacent spacers, the annular body 7011, and the winding. The second fluid channel 702b is formed by the cooperation of two adjacent spacer members 7012 and two adjacent annular bodies 7011.

[0116] Based on the oil-cooling heat dissipation logic described above, the first fluid channel 702a is in close contact with the surface of the high-voltage winding 220 or the low-voltage winding 230, allowing direct contact with the heating winding and rapid absorption of the heat loss generated during winding operation. The second fluid channel 702b, formed by the multi-layer coaxial ring support unit 701, is interconnected with the inner first fluid channel 702a. The insulating liquid 103 in the transformer tank can flow through both the first fluid channel 702a and the second fluid channel 702b simultaneously, thus widening the oil flow path. Under natural convection conditions, the hot oil can flow upwards synchronously within the multi-layer fluid channels, and after being cooled by the tank heat dissipation structure 104, it flows back, forming a multi-layer circulating convection. When forced convection is achieved using an oil pump, the multiple parallel oil channels effectively increase the oil heat exchange area, reduce oil flow resistance, and significantly improve heat dissipation efficiency.

[0117] Meanwhile, the multi-layer coaxial ring support unit 701 can form a multi-layer insulation barrier between the high-voltage winding 220 and the low-voltage winding 230, isolating the windings layer by layer, increasing the electrical creepage distance, improving the overall insulation withstand voltage performance, and avoiding the risk of local electric field concentration, breakdown and short circuit; the multi-layer spacer component 7012 supports the windings at multiple points and layers, disperses the radial X force on the windings, avoids local compression deformation of the windings and damage to the wire insulation, and improves the operating stability of the windings.

[0118] Specifically, please refer to Figure 20 and Figure 21 When the second insulating support ring 70112 is disposed on the outer periphery of the first insulating support ring 70111, the first support bar 70121 on the first insulating support ring 70111 abuts against the inner wall of the adjacent second insulating support ring 70112, the first support segment 701221 abuts against the outer peripheral surface of the high voltage winding 220 or the inner peripheral surface of the low voltage winding 230 in the radial direction X, and a gap 703 is provided between the second support segment 701222 and the outer peripheral surface of the high voltage winding 220 or the inner peripheral surface of the low voltage winding 230.

[0119] Please see Figure 22 When the first insulating support ring 70111 is disposed on the outer periphery of the second insulating support ring 70112, the first support segment 701221 abuts against the inner wall of the first insulating support ring 70111 in the radial direction X, and the second support segment 701222 is provided with a gap 703 between itself and the first insulating support ring 70111 in the radial direction X. The first support bar 70121 on the first insulating support ring 70111 abuts against the circumferential surface of the high voltage winding 220 or the circumferential surface of the low voltage winding 230 in the radial direction X.

[0120] Please see Figure 23 When there are two or more first insulating support rings 70111 and two first insulating support rings 70111 are arranged adjacent to each other, the first support bar 70121 on one first insulating support ring 70111 abuts against the adjacent first insulating support ring 70111 in the radial X direction to define at least one second fluid channel 702b. Please see Figure 24 When there are two or more second insulating support rings 70112, and two second insulating support rings 70112 are arranged adjacent to each other, a first support segment 701221 on one second insulating support ring 70112 abuts against the adjacent second insulating support ring 70112 in the radial direction X to define at least one second fluid channel 702b. A gap 703 is provided between the second support segment 701222 and the adjacent second insulating support ring 70112 in the radial direction X. See [reference] Figure 15 .

[0121] Therefore, the embodiments of this application can be flexibly selected in conjunction with the two support bar structures described above. Either the first support bar 70121 with a uniform axial Y-section can be used throughout, achieving uniform axial Y-support, eliminating the corner rings at both ends of the winding, and simplifying parts and assembly; or a second support bar 70122, narrower at both ends and thicker in the middle, can be used, relying on the reserved gap 703 in the second support section 701222 to optimize the end electric field distribution and adapt to different insulation and temperature rise design requirements. The multi-layer ring support unit 701 has universal parts; simply increasing or decreasing the quantity can adapt to transformer products with different capacities and winding sizes, offering strong versatility, facilitating standardized production and processing, and reducing mold and manufacturing costs.

[0122] Please see Figure 16 In this embodiment, the first support bar 70121 has a uniform cross-sectional dimension along the axial direction Y, meaning that the radial thickness X and circumferential width R of the first support bar 70121 remain constant along the axial direction Y. This uniform cross-section ensures that the radial spacing X between adjacent insulating support rings is consistent along the axial direction Y, resulting in multiple fluid channels formed between adjacent support bars and insulating support rings having a uniform cross-sectional area. This guarantees stable flow velocity and uniform pressure drop of the transformer oil within the channels, facilitating uniform heat dissipation of the winding along the entire axial height Y, effectively avoiding local turbulence caused by abrupt changes in the cross-sectional area of ​​the fluid channels, and reducing the hot spot temperature of the winding.

[0123] Please see Figure 17 In this embodiment, the second support bar 70122 is designed as a stepped structure, comprising a first support segment 701221 and second support segments 701222 located at both ends of the first support segment 701221. When the second support bar 70122 is disposed on the second insulating support ring 70112, the radial X width of the first support segment 701221 is relatively large, and the outer surface of the first support segment 701221 is in close contact with the inner surface of the first insulating support ring 70111. The radial X height of the second support segments 701222 located at both ends of the axial Y direction is relatively small, thus forming a gap 703 between the second support segment 701222 and the inner surface of the first insulating support ring 70111. The radial X dimension (width) of the first support segment 701221 is determined by the safety insulation distance, and the radial X dimension of the second support segment 701222 is determined by subtracting the dimensions of the first support segments 701221 on both sides from the overall height of the winding. The function of gap 703 is to provide space for the installation of the corner rings described below, and it can also serve as a fluid channel to enhance the end cooling of the transformer.

[0124] For example, in the radial direction X, the centers of adjacent first support bars 70121 and second support bars 70122 are located on the same straight line, that is, the centers of the inner and outer support bars arranged in alignment along the circumferential direction R are on the same radial X straight line. The support bars extend along the axial direction Y, and the fluid channel formed between the support bars reduces the flow resistance of the insulating oil and improves the heat dissipation efficiency. At the same time, the alignment arrangement can also strengthen the radial X support strength between the multi-layer annular body 7011, making the insulation gap 703 and electric field distribution more uniform, avoiding local stress concentration and electric field distortion, improving insulation reliability and structural stability, and facilitating assembly and processing, thus improving product consistency.

[0125] Please see Figure 15 The materials used for the annular body 7011 can be any one or more combinations of insulating paperboard (such as unbleached sulfate wood pulp paper or high-density cellulose paperboard) and glass fiber reinforced epoxy resin. When insulating paperboard is used for the annular body 7011, the annular body 7011 can be formed by winding a single sheet of insulating paperboard, or by stacking multiple sheets of insulating paperboard to form a single-layer or multi-layer ring structure, and is not limited to a closed ring form. The materials used for the spacer member 7012 can be any one or more combinations of insulating paperboard (such as T4 or T3 paperboard), glass fiber reinforced epoxy resin, and electrical laminate board.

[0126] Please see Figures 18 to 21 The annular body 7011 and the spacer member 7012 are integrally molded. This allows the annular support unit 701 to be an insulating cylinder with comb-shaped spacer members 7012, which can be manufactured using injection molding or compression molding processes to improve mechanical strength and production efficiency. In other examples, the spacer member 7012 can be manufactured separately and then bonded or press-fitted to the outer or inner circumferential surface of an annular body 7011.

[0127] Along the circumferential direction R of the annular main body 7011, the linear distance between two adjacent spacer members 7012 is 10mm to 30mm; along the circumferential direction R of the annular main body 7011, the linear dimension of the spacer member 7012 is 6mm to 10mm; the radial dimension of the spacer member 7012 is 4mm to 8mm. This arrangement ensures that the cross-sectional area of ​​the fluid channel 702, the insulation distance, and the mechanical support strength are matched to a certain extent, allowing the insulating liquid 103 to flow smoothly to improve heat dissipation efficiency, while also meeting the main insulation strength requirements under medium-frequency and medium-voltage operating conditions. Furthermore, it improves the stability and reliability of the insulation support structure 700, reduces the overall radial dimension X of the power conversion device, and increases power density. Specifically, the linear distance between two adjacent spacer members 7012 in the circumferential direction R is the shortest distance (i.e., chord length) from one spacer member 7012 to another; the dimension of the spacer member 7012 in the circumferential direction R is the width of the spacer member 7012; and the radial dimension of the spacer member 7012 in the radial direction X is the radial thickness.

[0128] In some examples, the straight-line distance between two adjacent spacer members 7012 can be 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 30mm, or any range between two of the above values. During measurement, along the circumferential R-tangent direction on the same circumference of the same annular body 7011, an electronic vernier caliper is used to measure the straight-line distance between the same side edges of two adjacent spacer members 7012, avoiding corner arcs. The same annular body 7011 is divided into three equal measuring points, and the average value is taken.

[0129] Please see Figure 19 When the centers of any two adjacent spacers 7012 along the radial X direction are located on the same radial X straight line, the circumferential R-distance between two adjacent spacers 7012 on the inner ring body 7011 is smaller than the circumferential R-distance between two adjacent spacers 7012 on the outer ring body 7011. This adapts to the circumference difference of the ring bodies 7011 with different radii, ensuring that the fluid channel 702 is uniformly connected throughout the entire range and the oil flow resistance is matched. At the same time, it enables the inner ring to have higher support strength and a more uniform electric field distribution, and the outer ring to have a larger heat dissipation channel 1042 area. This achieves synergistic optimization of insulation performance, mechanical strength and heat dissipation efficiency, and improves the overall power density and operational reliability of the power conversion device.

[0130] The linear dimension of the spacer member 7012 in the circumferential direction R can be 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm, or any range between two of the above values. During measurement, the circumferential R width of a single spacer member 7012 is measured linearly along the tangent to the end face of the spacer member 7012 in the circumferential direction R, using vernier calipers clamped on both outer edges of the spacer member 7012 body. Measurements are taken at least once each in the axial direction Y at the middle and both ends of each spacer member 7012.

[0131] The dimension of the spacer member 7012 along the radial X direction can be 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, or any range between two of the above values. During measurement, the distance is measured vertically along the radius (radial X) of the annular body 7011, from the inner surface of the spacer member 7012 adhering to the inner annular body 7011 to the outer surface of the outer annular body 7011, using an outside micrometer.

[0132] Based on standard medium-voltage power conversion device design experience, for 10kV level power conversion devices, the bay component 7012 adopts the above parameters. These parameters need to be optimized according to the specific voltage level, loss density and cooling requirements.

[0133] In another implementation of this embodiment, the insulating support structure 700 can also adopt a simplified structure, namely, including multiple annular bodies 7011, with any two adjacent annular bodies 7011 directly attached in the radial X direction, without the spacer 7012 and fluid channel 702. This structure is suitable for low-voltage applications with low losses and low heat dissipation requirements, and can reduce manufacturing costs.

[0134] This application, by setting up insulating support structures 700 on both the inner and outer sides of the high-voltage winding 220, not only provides a reliable main insulation distance for the high-voltage winding 220 (to the ground potential of the core column 210 and to the external low-voltage winding 230), but also utilizes the spacer member 7012 to form an efficient and orderly fluid channel 702. The insulating support structure 700 combines insulation and heat dissipation functions, effectively suppressing the formation of small bridges of impurities in the power conversion device oil (the probability can be reduced to below 0.5%), and improving the dielectric strength of the insulation. At the same time, since the low-voltage winding 230 is located on the outermost side and has a lower potential, there is no need to reserve a large insulation distance between the low-voltage winding 230 and the grounded metal housing 100, thereby compressing the overall size of the device and increasing the power density. Simulation and experiments show that, at the same voltage level, the structure of this application can reduce the size of the power conversion device by 15% to 25%.

[0135] The power conversion module of this application may also include other necessary circuits, such as a medium-voltage side conversion module, control circuit, drive circuit, sampling circuit, heat sink, etc. Because the power conversion device of this application features high efficiency, high power density, and low stray loss, the power conversion module containing this power conversion device also possesses these advantages, making it particularly suitable for applications such as solid-state power conversion devices, power quality conditioners, and renewable energy grid-connected inverters.

[0136] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0137] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0138] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A power conversion device, characterized in that, The power conversion device includes: The enclosure, wherein at least one surface of the enclosure is provided with a low-pressure sleeve and a high-pressure sleeve; A transformer body, disposed within the housing, includes a magnetic core, a high-voltage winding, and a low-voltage winding. The magnetic core includes a core post. The high-voltage winding is sleeved around the outer periphery of the core post and radially insulated from it. The low-voltage winding is sleeved around the outer periphery of the high-voltage winding and radially insulated from it. A first conversion module is disposed within the housing. The first conversion module has an input side and an output side. The input side of the first conversion module is electrically connected to the low-voltage winding, and the output side of the first conversion module is electrically connected to the low-voltage bushing. The voltage frequency of the input side of the first conversion module is higher than the voltage frequency of the output side of the first conversion module.

2. The power conversion device according to claim 1, characterized in that, The housing is filled with an insulating liquid, and the first conversion module is immersed in the insulating liquid.

3. The power conversion device according to claim 2, characterized in that, The power conversion device further includes two end fixing members and multiple fixing posts. The two end fixing members are respectively disposed at both ends of the transformer body in the axial direction, and each fixing post connects the two end fixing members. The first conversion module is disposed between the low-voltage winding and the inner wall of the housing and is connected to the two end fixing members.

4. The power conversion device according to claim 3, characterized in that, The power conversion device further includes a fixing plate and a connecting plate; the fixing plate is disposed between the low-voltage winding, the first conversion module and the inner wall of the housing, and the two ends of the fixing plate along the axial direction are respectively connected to the end fixing member through the connecting plate.

5. The power conversion device according to claim 2, characterized in that, The component packaging material of the first conversion module is chemically compatible with the insulating liquid.

6. The power conversion device according to claim 1, characterized in that, The power conversion device further includes a sealing structure, which and the first conversion module are both disposed on the inner wall of the housing, and the sealing structure covers the outer periphery of the first conversion module.

7. The power conversion device according to claim 1, characterized in that, The input side of the first conversion module is electrically connected to the low-voltage winding via a first lead, the output side of the first conversion module is electrically connected to the low-voltage bushing via a second lead, and the high-voltage winding is electrically connected to the high-voltage bushing via a third lead.

8. The power conversion device according to any one of claims 1 to 7, characterized in that, The power conversion device further includes a second conversion module, which is disposed outside the housing and electrically connected to the transformer body, wherein the output voltage of the second conversion module is greater than the output voltage of the first conversion module.

9. The power conversion device according to any one of claims 1 to 7, characterized in that, The power conversion device further includes: A heat dissipation structure is connected to the housing.

10. The power conversion device according to claim 1, characterized in that, The power conversion device further includes an insulating support structure, which is radially disposed between the core column and the high-voltage winding, and between the high-voltage winding and the low-voltage winding.

11. The power conversion device according to claim 10, characterized in that, The high-voltage winding includes multiple first winding layers arranged coaxially along the radial direction, and the multiple first winding layers are electrically connected to each other; each first winding layer is formed by winding multiple turns of first coil layer by layer along the axial direction; The insulating support structure is also radially disposed between any two adjacent first winding layers.

12. The power conversion device according to claim 11, characterized in that, In the case where at least two adjacent first winding layers are interconnected, the innermost first winding layer is provided with a first connection end, and the outermost first winding layer is provided with a second connection end.

13. The power conversion device according to claim 12, characterized in that, The low-voltage winding includes a plurality of second winding layers, which are stacked axially and coaxially arranged. Each second winding layer includes a disc-shaped segment and a cylindrical segment connected axially. The disc-shaped segment includes multiple turns of first thread layers, which are concentrically wound radially from the outside to the inside, and the outermost first thread layer is provided with a third connecting end; the cylindrical segment includes multiple turns of cylindrical sub-segments, which are arranged radially and connected to each other, and each cylindrical sub-segment includes multiple turns of second thread layers arranged axially, the outermost second thread layer is provided with a fourth connecting end, and the innermost first thread layer and the innermost cylindrical sub-segment's second thread layer are connected.

14. The power conversion device according to claim 13, characterized in that, The first connection end and the second connection end are both located on the same side of the high voltage winding, and the third connection end and the fourth connection end are both located on the same side of the low voltage winding; The first connecting end and the second connecting end have a first orthographic projection on the reference plane, and the third connecting end and the fourth connecting end have a second orthographic projection on the reference plane. The first orthographic projection and the second orthographic projection do not coincide, wherein the reference plane is perpendicular to the axial direction.

15. The power conversion device according to claim 12, characterized in that, The number of low-voltage windings is greater than the number of high-voltage windings.

16. The power conversion device according to claim 10, characterized in that, The insulating support structure includes an annular support unit, which includes an annular body and a plurality of axially extending spacers disposed on the annular body, the plurality of spacers being spaced apart circumferentially along the annular body. The annular support unit abuts radially against the circumferential surface of the high-voltage winding or the circumferential surface of the low-voltage winding to define at least one first fluid channel.

17. The power conversion device according to claim 16, characterized in that, The annular body of the ring support unit is configured as a first insulating support ring. The spacer includes a plurality of first support bars, which are spaced apart on the first insulating support ring along the circumferential direction. The first support bars abut against the circumferential surface of the high voltage winding or the circumferential surface of the low voltage winding in the radial direction. or, The annular body of the ring support unit is configured as a second insulating support ring. The spacer member includes a plurality of second support bars, which are spaced apart on the second insulating support ring along the circumference. Each second support bar includes a first support segment and two second support segments. The two second support segments are respectively connected to the two ends of the first support segment in the axial direction. The first support segment abuts against the circumferential surface of the high-voltage winding or the circumferential surface of the low-voltage winding in the radial direction. A gap is provided between the second support segment and the circumferential surface of the high-voltage winding or the circumferential surface of the low-voltage winding in the radial direction.

18. The power conversion device according to claim 10, characterized in that, The insulating support structure includes multiple coaxially arranged annular support units. Each annular support unit includes an annular body and multiple axially extending spacer members disposed on the annular body. The multiple spacer members are spaced apart circumferentially along the annular body. In one of the annular support units, the spacer member abuts radially against the circumferential surface of the high-voltage winding or the circumferential surface of the low-voltage winding to define at least one first fluid channel, and the spacer member of the other annular support unit abuts radially against the annular body of the adjacent annular support unit to define at least one second fluid channel.

19. The power conversion device according to claim 18, characterized in that, The annular support unit comprises a first insulating support ring and a second insulating support ring; the first insulating support ring and the second insulating support ring are coaxially arranged; the spacer comprises a plurality of first support bars and a plurality of second support bars, the plurality of first support bars being spaced apart on the first insulating support ring along the circumference; the plurality of second support bars being spaced apart on the second insulating support ring along the circumference; each second support bar comprises a first support segment and two second support segments, the two second support segments being respectively connected to the two ends of the first support segment in the axial direction; When the second insulating support ring is disposed on the outer periphery of the first insulating support ring, the first support bar on the first insulating support ring abuts against the inner wall of the adjacent second insulating support ring in the radial direction, the first support segment abuts against the circumferential surface of the high voltage winding or the circumferential surface of the low voltage winding in the radial direction, and a gap is provided between the second support segment and the circumferential surface of the high voltage winding or the circumferential surface of the low voltage winding in the radial direction. When the first insulating support ring is disposed on the outer periphery of the second insulating support ring, the first support segment abuts against the inner wall of the first insulating support ring in the radial direction, the second support segment has the gap between it and the first insulating support ring in the radial direction, and the first support bar on the first insulating support ring abuts against the circumferential surface of the high voltage winding or the circumferential surface of the low voltage winding in the radial direction.

20. The power conversion device according to claim 19, characterized in that, When there are two or more first insulating support rings and two first insulating support rings are arranged adjacent to each other, the first support bar on one of the first insulating support rings abuts against the adjacent first insulating support ring in the radial direction to define at least one second fluid channel. When there are two or more second insulating support rings and two second insulating support rings are arranged adjacent to each other, the first support segment on one of the second insulating support rings abuts against the adjacent second insulating support ring in the radial direction to define at least one second fluid channel, and the second support segment is provided with the gap between itself and the adjacent second insulating support ring in the radial direction.

21. The power conversion device according to claim 16 or 18, characterized in that, The annular main body and the spacer are integrally formed.

Images