Converter structure and power generation system with same

Abstract

The invention provides a current converter structure and a power generation system with the same, and the current converter structure comprises a housing which is internally provided with an accommodation space; the current converter body is arranged in the containing space, a gap is formed between the current converter body and the inner wall of the shell, at least part of the gap is filled with insulating liquid, and the current converter body is immersed in the insulating liquid; the supporting insulating part is arranged below the shell; and the connecting terminal passes through the top of the shell and is connected with the converter body. According to the technical scheme of the invention, the problem that the size of an offshore wind power direct current sending-out current converter in the prior art is large is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of converter technology, and more specifically, to a converter structure and a power generation system having the same. Background Technology

[0002] Offshore wind power resources are abundant, and transmitting wind power via DC transmission is an important trend in offshore wind power development. The series boost topology of all-DC offshore wind farms has attracted widespread attention due to its simple structure and the elimination of the need for an offshore converter station. This topology can significantly reduce power collection and transmission costs. However, the converter units at higher potentials in the series boost method pose significant challenges to insulation design, especially for ±500kV DC voltages. Traditional air-insulated, water-cooled technology necessitates placing the converter valve tower in an indoor valve hall to ensure sufficient insulation distance.

[0003] The limitation of air insulation lies in its low withstand voltage level, resulting in enormous valve hall sizes for offshore converter stations. For example, a ±400kV valve hall measures 39m × 60m × 21.5m and weighs over 20,000 tons, while the actual converter tower occupies only a small portion of the space. This not only increases the cost of offshore wind power projects but also restricts the layout and construction of offshore wind farms. Air insulation is the main factor contributing to the large size and heavy weight of offshore converter stations, becoming one of the bottlenecks in the development of offshore wind power.

[0004] In traditional converter stations, the converter cooling system typically employs forced water cooling, the complexity of which and its reliability have always been a focus of industry attention. For offshore wind power converters, the power supply and extraction of heat sinks at high potentials are even more complex, increasing the difficulty of system design. Furthermore, air-insulated cooling systems are less efficient when dealing with high heat flux density semiconductor devices, requiring additional cooling equipment, which further increases the size and weight of the equipment.

[0005] In summary, the main problems faced by existing offshore wind power DC transmission converter technology are: the large size and excessive weight of the converter valve tower due to the air insulation design, and the complexity of the cooling system caused by the power supply and extraction of high-potential radiators. Summary of the Invention

[0006] The main objective of this invention is to provide a converter structure and a power generation system having the same, so as to solve the problem of large size of offshore wind power DC transmission converters in related technologies.

[0007] To achieve the above objectives, according to one aspect of the present invention, a converter structure is provided, comprising: a housing having an internal accommodating space; a converter body disposed within the accommodating space, a gap being formed between the converter body and the inner wall of the housing, at least a portion of the gap being filled with an insulating liquid, the converter body being immersed in the insulating liquid; a supporting insulating member disposed below the housing; and a connecting terminal passing through the top of the housing and connected to the converter body.

[0008] Furthermore, there are gaps between the converter body and any inner wall of the casing.

[0009] Furthermore, the housing includes a top wall, a bottom wall, and a surrounding wall, with the surrounding wall located between the top wall and the bottom wall. There is a first gap between the converter body and the bottom wall, and a second gap between the converter body and the top wall. The first gap is smaller than the second gap.

[0010] Furthermore, the enclosure includes a first side wall, a second side wall, a third side wall, and a fourth side wall, which are connected sequentially. There is a third gap between the converter body and the first side wall, a fourth gap between the converter body and the second side wall, a fifth gap between the converter body and the third side wall, and a sixth gap between the converter body and the fourth side wall. The third gap is smaller than the fifth gap, the fourth gap is greater than or equal to the fifth gap, and the sixth gap is less than or equal to the third gap.

[0011] Furthermore, the ratio of the sixth gap to the fourth gap is between 0.45 and 0.75.

[0012] Furthermore, the ratio between the first gap and the sixth gap is between 0.9 and 1.1.

[0013] Furthermore, the sum of the first gap, the third gap, the fourth gap, the fifth gap, and the sixth gap is less than the second gap.

[0014] Furthermore, the top wall and the enclosure wall are detachably provided, and / or the housing also includes a suspension structure connected between the top wall of the housing and the converter body.

[0015] Furthermore, the connection terminals include a series terminal output line, a series terminal input line, a first discrete AC port, and a second discrete AC port. The series terminal output line, the series terminal input line, the first discrete AC port, and the second discrete AC port are all spaced apart, and the series terminal output line is located at the center of the converter body.

[0016] Furthermore, the diameter of the lead wire at the series terminal gradually increases from the direction closest to the shell to the direction furthest from the shell.

[0017] Furthermore, the plane passing through the center line of the series terminal outlet and the center line of the series terminal inlet is set as the first preset plane, and the plane passing through the center line of the first discrete AC port and the center line of the second discrete AC port is set as the second preset plane. The first preset plane and the second preset plane are set perpendicularly.

[0018] Furthermore, the length of the series-connected outgoing line is greater than the length of the series-connected incoming line, the length of the series-connected outgoing line is greater than the length of the first discrete AC port, and the length of the series-connected outgoing line is greater than the length of the second discrete AC port.

[0019] Furthermore, the converter structure also includes a heat dissipation structure, which is installed on the outer wall of the housing.

[0020] Furthermore, the heat dissipation structure includes a cover and a pipe disposed within the cover, the pipe being connected to the receiving space and coiled around it.

[0021] According to another aspect of the present invention, a power generation system is provided, including a converter structure, wherein the converter structure is the converter structure described above.

[0022] The technical solution of this invention includes an internal housing with a accommodating space. The converter body is housed within this space, with a gap between the converter body and the inner wall of the housing. The converter body is immersed in an insulating liquid. A supporting insulating component is located at the bottom of the housing. Connecting terminals are inserted through the top of the housing and connected to the converter body. This arrangement, immersing the converter body in the insulating liquid inside the housing, effectively solves the insulation problem at high potentials. The insulating liquid provides superior insulation performance compared to air, significantly shortening the necessary insulation distance and thus reducing the overall volume and weight of the converter. Furthermore, because the supporting insulating component supports the housing, it separates the housing from the ground, allowing insulation from the external air, thereby reducing the insulation pressure of the insulating liquid. This arrangement also reduces the amount of insulating liquid used. In addition, the above structure promotes efficient internal cooling; the insulating liquid not only provides insulation but also removes heat generated during converter operation through natural circulation via liquid-gas phase change, eliminating the need for an additional power source and improving the system's self-sufficiency and stability. The supporting insulation components located beneath the housing further ensure the equipment's insulation from ground, while the connection terminals ensure a safe and reliable connection between the converter body and the external circuitry. Therefore, the technical solution of this application effectively solves the problem of the large size of offshore wind power DC transmission converters in related technologies. Attached Figure Description

[0023] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0024] Figure 1 A three-dimensional structural schematic diagram of an embodiment of the converter structure according to the present invention is shown;

[0025] Figure 2 It shows Figure 1 A three-dimensional structural diagram of the converter structure from another perspective;

[0026] Figure 3 It shows Figure 1 A front view schematic diagram of the converter structure;

[0027] Figure 4 It shows Figure 3 A schematic diagram of the converter structure in the AA direction;

[0028] Figure 5 It shows Figure 3 A schematic cross-sectional view of the converter structure from the BB direction;

[0029] Figure 6 It shows Figure 1 An exploded view of the converter structure;

[0030] Figure 7 It shows Figure 6 A schematic diagram of the structure of the converter housing;

[0031] Figure 8 It shows Figure 6 A schematic diagram of the converter body structure;

[0032] Figure 9 It shows Figure 8 A front view schematic diagram of the structure at the converter body;

[0033] Figure 10 It shows Figure 9 A top view of the structure at the converter body.

[0034] The above figures include the following reference numerals:

[0035] 10. Housing; 11. Accommodation space; 12. Top wall; 13. Bottom wall; 14. Enclosure wall; 141. First side wall; 142. Second side wall; 143. Third side wall; 144. Fourth side wall; 20. Converter body; 30. Supporting insulation component; 40. Connection terminal; 41. Series terminal outlet; 42. Series terminal inlet; 43. First discrete AC port; 44. Second discrete AC port; 51. First gap; 52. Second gap; 53. Third gap; 54. Fourth gap; 55. Fifth gap; 56. Sixth gap; 60. Suspension structure; 70. Heat dissipation structure. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0038] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0039] In addressing the challenges of DC transmission technology for offshore wind power, the inventors conducted in-depth research into the limitations of current series-boost converter topologies. Particularly in ±500kV DC applications, the excessively large and heavy valve halls resulting from traditional air-insulated, water-cooled technology drew significant attention. For example, the valve hall of an offshore converter station, at a massive 39m × 60m × 21.5m volume and weighing over 20,000 tons, is designed to accommodate the converter valve tower, which accounts for only 8% of its volume and 6% of its weight. This extreme mismatch highlights the limitations and high cost of air-insulated technology, severely impacting the economic feasibility and layout flexibility of offshore wind power projects.

[0040] Furthermore, regarding the challenges of power supply and extraction for high-potential heat sinks, and the inefficiency of air-insulated cooling systems when handling high heat flux density semiconductor devices, the inventors recognized that these technical obstacles not only increased system complexity and maintenance costs, but also restricted the miniaturization and lightweight development of offshore wind power converters. In particular, for the construction of offshore wind farms, high costs and space constraints have become key technical bottlenecks.

[0041] Based on the above analysis, the inventors clarified the direction of technological improvement, namely, to seek a new insulation solution that can significantly reduce the size and weight of the converter, while simplifying the structure of the cooling system and overcoming the problem of the complexity of power supply to the radiator at high potential.

[0042] Specifically, such as Figures 1 to 7 As shown, in this embodiment, the converter structure includes: a housing 10, a converter body 20, a supporting insulating member 30, and a connecting terminal 40. The housing 10 has an internal accommodating space 11. The converter body 20 is disposed within the accommodating space 11, and a gap exists between the converter body 20 and the inner wall of the housing 10. At least a portion of the gap is filled with an insulating liquid, and the converter body 20 is immersed in the insulating liquid. The supporting insulating member 30 is disposed below the housing 10. The connecting terminal 40 passes through the top of the housing 10 and connects to the converter body 20.

[0043] Using the technical solution of this embodiment, the housing 10 has an internal accommodating space 11, and the converter body 20 is disposed within the accommodating space 11. A gap exists between the converter body 20 and the inner wall of the housing 10, and the converter body 20 is immersed in an insulating liquid. A supporting insulating member 30 is disposed below the housing 10. A connecting terminal 40 passes through the top of the housing 10 and connects to the converter body 20. Through the above arrangement, immersing the converter body 20 in the insulating liquid inside the housing 10 effectively solves the insulation problem at high potentials. The insulating liquid provides superior insulation performance compared to air, significantly shortening the necessary insulation distance, thereby reducing the overall volume and weight of the converter. Furthermore, because the supporting insulating member 30 supports the housing 10, the housing 10 can be separated from the ground, thus achieving insulation against the external air. This reduces the insulation pressure of the insulating liquid and decreases the amount of insulating liquid used. In addition, the above structure promotes efficient internal cooling; the insulating liquid not only provides insulation but also removes heat generated during converter operation through natural circulation via liquid-gas phase change, eliminating the need for an additional power source and improving the system's self-sufficiency and stability. The supporting insulating member 30 located below the housing 10 further ensures the equipment's insulation from the ground, while the connection terminal 40 ensures a safe and reliable connection between the converter body 20 and the external circuitry. Therefore, the technical solution of this embodiment effectively solves the problem of the large size of offshore wind power DC transmission converters in related technologies.

[0044] Currently, there are two main technical solutions for the insulation of converters: gas insulation and liquid immersion insulation. If the converter body volume is set as a three-dimensional volume of a×b×c, for a 500 kV converter, the insulation distance for gas insulation is about 5 meters, and its valve hall volume is a×b×c+100×(ab+bc+ac)+1000 cubic meters; the insulation distance for liquid immersion insulation is about 0.5 meters, and its equipment volume is a×b×c+ab+bc+ac+1 cubic meter.

[0045] The internal insulation distance of the insulation method in this application is 0.05 meters, and the equipment volume is a×b×c+0.1×(ab+bc+ac)+0.01 cubic meters.

[0046] In terms of insulation distance and insulation volume, the technical solution of this application has significant advantages, and can save up to 90% of the amount of fluorinated liquid compared with liquid immersion insulation.

[0047] It should be noted that the insulating liquid mentioned above is a fluorinated liquid. The fluorinated liquid provides internal insulation from the converter body 20 to the top wall 12, with an insulation level of 50 kV or higher.

[0048] The supporting insulating component 30 achieves insulation to ground, with an insulation level of 500 kV or above.

[0049] Specifically, the converter structure significantly improves upon the problems of large size, excessive weight, and complex cooling systems faced by converters in offshore wind power DC transmission. During operation, the converter body 20 is completely immersed in the insulating liquid inside the housing 10. The high insulation performance of the insulating liquid significantly reduces the insulation distance between the internal components of the converter body 20 and the housing 10, effectively compressing the overall volume and reducing the weight of the converter structure. During power conversion, the cooling characteristics exhibited by the insulating liquid during the two-phase conversion process provide efficient internal cooling for the converter body 20, eliminating the need for an additional power source, greatly simplifying the cooling system, and enhancing the system's adaptive cooling capability. The external supporting insulation component 30 not only stably supports the converter structure but also provides necessary external insulation in high-potential environments, ensuring electrical safety. During equipment operation, the connection terminal 40, through its design passing through the top of the housing 10, not only ensures a reliable connection between the converter body 20 and external circuits but also allows for convenient access to the converter body 20 during equipment maintenance or inspection, simplifying the maintenance process.

[0050] In summary, this innovative combination of insulation and cooling, through optimized converter structure, is particularly suitable for offshore wind power DC transmission systems, effectively reducing the construction and operation and maintenance costs of offshore wind power projects and improving the system's operating efficiency and reliability.

[0051] This design is better adapted to the marine environment, reduces space requirements, and at the same time, reduces energy consumption during power conversion through natural circulation cooling, achieving a more economical and environmentally friendly offshore wind power DC transmission solution.

[0052] As can be seen from the above, the inventors have clearly defined the technical improvement goals of reducing the size and weight of the converter structure and simplifying the structure of the cooling system. After clarifying the improvement goals, the inventors began to explore innovative solutions that can meet these needs at the same time.

[0053] In this process, the inventors first reviewed the characteristics and applicable scenarios of various insulation technologies, realizing that liquid insulating media, due to their high insulation performance and compactness, became a potential choice for reducing valve hall size and weight. Compared with air insulation, liquid insulating media such as fluorinated liquids can provide the same insulation effect over a shorter distance, which makes it possible to place the converter body 20 in a smaller enclosed space.

[0054] However, relying solely on liquid insulation to solve all problems is impractical, as the contact between the converter body 20 and the housing 10 may cause localized electric field inhomogeneities, thus affecting the insulation effect. To address this issue, the inventors devised a design that maintains a certain gap between the converter body 20 and the housing 10.

[0055] In their study of the heat flux density distribution within the converter structure, the inventors noticed that heat-generating components such as semiconductor devices are located in regions of high heat flux density, which are precisely the areas requiring focused cooling. By designing a gap between the converter body 20 and the housing 10, space can be provided for the free circulation of the fluorinated liquid, enabling efficient cooling by utilizing the characteristics of liquid-gas phase change. Simultaneously, this gap can also optimize the electric field distribution, ensuring that the converter maintains stable insulation performance even under high-voltage conditions.

[0056] In addition, the inventors also considered that the combination of external natural air cooling and internal liquid cooling can form a natural cooling cycle, thereby overcoming the complexity of power supply for radiators under high potential.

[0057] like Figure 4 and Figure 5 As shown, in this embodiment, there is a gap between the converter body 20 and any inner wall of the housing 10. This structure ensures free circulation of the internal fluorinated liquid, promoting not only the two-phase cooling process in areas of high heat flux density but also maintaining good internal insulation performance. When the converter is operating, internal heat-generating components such as semiconductor devices are cooled by the liquid-gas phase change of the fluorinated liquid. The gas generated during the phase change can rise along the gap to the top of the housing 10 and return to the liquid state through natural air cooling, forming an effective circulating cooling path. Furthermore, the presence of this gap optimizes the electric field distribution inside the converter body 20, reduces the electric field strength at critical points, and further improves the insulation reliability of the equipment.

[0058] like Figures 1 to 5As shown, in this embodiment, the housing 10 includes a top wall 12, a bottom wall 13, and a surrounding wall 14. The surrounding wall 14 is located between the top wall 12 and the bottom wall 13. A first gap 51 is formed between the converter body 20 and the bottom wall 13, and a second gap 52 is formed between the converter body 20 and the top wall 12. The first gap 51 is smaller than the second gap 52. The housing 10 includes a top wall 12, a bottom wall 13, and a surrounding wall 14. The surrounding wall 14 is located between the top wall 12 and the bottom wall 13, forming a closed space for accommodating the converter body 20 and the insulating liquid. The first gap 51 is provided between the converter body 20 and the bottom wall 13, while the second gap 52 is provided between the converter body 20 and the top wall 12. The first gap 51 is smaller than the second gap 52. This asymmetrical design aims to optimize the cooling efficiency and insulation performance of the converter. The smaller first gap 51 increases the circulation speed of the immersion cooling medium at the bottom of the converter body 20, enhancing the cooling effect on the heat source. Meanwhile, the larger second gap 52 ensures sufficient insulation distance between the top of the converter body 20 and the external environment, improving electrical safety. Furthermore, this design helps reduce the overall weight of the housing 10 by reducing the amount of cooling medium used and lowering the structural strength requirements of the housing 10, making the overall equipment lighter and more efficient. This is particularly suitable for DC transmission systems in offshore wind power, where higher demands are placed on equipment reliability and economy.

[0059] like Figures 1 to 5As shown, in this embodiment, the enclosure 14 includes a first side wall 141, a second side wall 142, a third side wall 143, and a fourth side wall 144, which are connected sequentially. A third gap 53 exists between the converter body 20 and the first side wall 141; a fourth gap 54 exists between the converter body 20 and the second side wall 142; a fifth gap 55 exists between the converter body 20 and the third side wall 143; and a sixth gap 56 exists between the converter body 20 and the fourth side wall 144. The third gap 53 is smaller than the fifth gap 55, the fourth gap 54 is greater than or equal to the fifth gap 55, and the sixth gap 56 is less than or equal to the third gap 53. The enclosure 14, formed by the sequential connection of the first side wall 141, the second side wall 142, the third side wall 143, and the fourth side wall 144, creates a closed space surrounding the converter body 20. The key to this design lies in the difference in the size of the gaps between the enclosure wall 14 and the converter body 20. Specifically, the third gap 53 between the converter body 20 and the first sidewall 141 is smaller than the fifth gap 55 between the converter body 20 and the third sidewall 143, while the fourth gap 54 between the converter body 20 and the second sidewall 142 is greater than or equal to the fifth gap 55, and the sixth gap 56 between the converter body 20 and the fourth sidewall 144 is less than or equal to the third gap 53. This asymmetrical gap design fully utilizes the different insulating properties of the fluorinated liquid, achieving precise control over the insulation requirements within the converter structure. On the one hand, the smaller third gap 53 and sixth gap 56 can effectively reduce the amount of fluorinated liquid used, thereby reducing the overall weight and cost; on the other hand, the larger fourth gap 54 and fifth gap 55 ensure sufficient insulation distance, especially between the converter body 20 and the second sidewall 142 and the third sidewall 143, to cope with possible electrical fluctuations and stress distribution, ensuring electrical safety.

[0060] In summary, this embodiment, by optimizing the gap layout between the enclosure 14 and the converter body 20, not only achieves a compact design of the equipment, but also takes into account electrical safety and economy, demonstrating the efficiency and rationality of the design.

[0061] like Figures 1 to 5As shown, in this embodiment, the ratio of the sixth gap 56 to the fourth gap 54 is between 0.45 and 0.75. This ratio is optimized to be between 0.45 and 0.75. The selection of this design parameter is based on an in-depth analysis of the heat flux density distribution within the converter structure, aiming to further improve the synergistic optimization of cooling efficiency and insulation performance. Specifically, this asymmetric gap ratio promotes the liquid-gas phase change circulation within the fluorinated liquid, ensuring more effective cooling of areas with higher heat flux density, while external natural air cooling more efficiently cools areas with lower heat flux density. Furthermore, by adjusting this ratio, the internal pressure distribution of the converter can be precisely controlled, reducing fluorinated liquid evaporation losses, extending the service life of the cooling medium, and reducing maintenance costs. This design not only helps improve the overall operational stability of the converter but also further reduces the size and weight of the equipment, enhancing the technical and economic efficiency of the offshore wind power DC transmission system.

[0062] Specifically, in this embodiment, the ratio of the sixth gap 56 to the fourth gap 54 is 0.55. Of course, in other embodiments, the above ratio can also be 0.45, 0.5, 0.6, 0.65, 0.7, 0.75, or other ratios.

[0063] like Figures 1 to 5 As shown, in this embodiment, the ratio between the first gap 51 and the sixth gap 56 is between 0.9 and 1.1. This specific ratio is chosen based on the optimized design of the liquid-gas phase change cooling process inside the converter and the effective utilization of external natural air cooling conditions. By finely adjusting the ratio of the first gap 51 and the sixth gap 56, the conversion between gas and liquid states during internal circulation of the fluorinated liquid can be ensured to be more efficient, thereby improving cooling performance.

[0064] Meanwhile, this ratio setting also takes into account the fluctuations in wind speed at offshore wind farms, ensuring that the external radiator maintains a stable cooling effect even in environments with changing wind speeds, avoiding a decrease in cooling efficiency due to reduced wind speed. This synergistic design of internal and external cooling systems not only improves the heat dissipation capacity of the converter but also enhances its adaptability and reliability in complex marine environments.

[0065] Specifically, in this embodiment, the ratio between the first gap 51 and the sixth gap 56 is 1. Of course, in other embodiments, the above ratio can also be 0.9, 0.92, 0.94, 0.96, 0.98, 1.12, 1.14, 1.16, 1.18, 1.2 or other ratios.

[0066] like Figures 1 to 5As shown, in this embodiment, the sum of the first gap 51, the third gap 53, the fourth gap 54, the fifth gap 55, and the sixth gap 56 is less than the second gap 52. The above design fully utilizes the characteristics of the internal spatial layout of the converter structure. By adjusting the proportions of the first gap 51, the third gap 53, the fourth gap 54, the fifth gap 55, and the sixth gap 56, a more compact structural design is achieved, further reducing the overall volume and weight of the converter structure and lowering costs.

[0067] In converter design under high-voltage environments, rationally planning the insulation distances at different locations is crucial. This asymmetric gap design strategy not only ensures the insulation safety of critical components but also optimizes the heat dissipation path in areas with high heat flux density within the converter structure, enhancing the system's reliability and stability. This design effectively addresses the complex and variable operating conditions of offshore wind power.

[0068] like Figures 6 to 9 As shown, in this embodiment, the top wall 12 and the enclosure wall 14 are detachably configured. This design allows for more flexible and convenient operation of the converter structure during maintenance and repair. Specifically, when the converter body 20 located inside the housing needs to be inspected or replaced, it can be lifted out as a whole by separating the top wall 12 and the enclosure wall 14, without disassembling complex internal wiring or rearranging the radiator position.

[0069] This modular assembly method not only significantly shortens maintenance time but also reduces the potential risk of failure caused by frequent disassembly and assembly, thereby improving equipment availability and operating efficiency.

[0070] Furthermore, the independent disassembly of the top wall 12 allows for upgrades to the converter's cooling system, such as adding more radiators or optimizing the fluoride circulation path as needed to accommodate the converter's operation at higher power densities. Therefore, this detachable top wall design not only enhances the converter's ease of maintenance.

[0071] In this embodiment, the converter body 20 is provided with a gas-liquid separator heat sink and power devices inside, with the power devices mounted on the gas-liquid separator heat sink.

[0072] Specifically, the gas-liquid separation radiator includes a radiator body with an internal clearance space. Power devices are mounted on the radiator body and pass through this clearance space. The top of the radiator body is open. A liquid inlet is located on the side wall of the radiator body. Fluorinated liquid can enter the interior of the radiator body through the liquid inlet and come into contact with the power devices. After the gas-liquid two-phase conversion is achieved, the gas can be discharged through the top of the radiator body.

[0073] The radiator body has multiple connecting rods arranged at intervals inside. The liquid inlet is inclined downwards. The liquid inlet is located on the side wall of the converter body 20 and communicates with the receiving space 11. That is, in this case, the top wall is not submerged in fluorinated liquid.

[0074] like Figures 6 to 9 As shown, in this embodiment, the housing 10 also includes a suspension structure 60, which is connected between the top wall 12 of the housing 10 and the converter body 20. The suspension structure 60, connected between the top wall 12 of the housing 10 and the converter body 20, forms a stable support and a convenient hoisting mechanism. The design of the suspension structure 60 not only enhances the safety of the converter during transportation and installation but also significantly improves the efficiency of maintenance and repair. When the converter body 20 needs to be hoisted, this structure allows it to be lifted out as a whole without disassembling the complex internal wiring, effectively simplifying the operation process and reducing maintenance costs.

[0075] In addition, the suspension structure 60 optimizes the spatial layout of the converter, enabling it to achieve efficient cooling and insulation within a limited space while also ensuring the compactness and operability of the equipment, reflecting the comprehensiveness and practicality of the design.

[0076] In other embodiments, the bottom wall of the housing 10 may also be provided with a support structure to support the converter body 20, thereby making the position of the converter body 20 more stable.

[0077] like Figure 1 , Figure 2 as well as Figures 8 to 10 As shown, in this embodiment, the connection terminal 40 includes a series terminal outlet 41, a series terminal inlet 42, a first discrete AC port 43, and a second discrete AC port 44. The series terminal outlet 41, series terminal inlet 42, first discrete AC port 43, and second discrete AC port 44 are all spaced apart, and the series terminal outlet 41 is located at the center of the converter body 20. Positioning the series terminal outlet 41 at the center of the converter body 20 not only optimizes the internal electrical layout but also fully utilizes the internal space of the converter structure, effectively alleviating the difficulty of insulation treatment for high-voltage outlet lines in critical areas.

[0078] During operation, when current enters the converter body 20 through the series input line 42, the current path is designed to be more compact due to the central location of the series output line 41. This promotes uniform distribution of the cooling medium within the converter, enhances cooling efficiency, and ensures stable operation of semiconductor devices under high loads. Simultaneously, the first discrete AC port 43 and the second discrete AC port 44 are distributed on the outer edge. This distributed layout helps to balance the overall heat load distribution of the equipment, ensuring consistent temperature control across all parts, preventing localized overheating, and improving the converter's thermal management and reliability. The overall structure of the converter is thus more compact, significantly improving space utilization. Furthermore, this layout simplifies equipment maintenance and repair processes, enhancing the ease of operation and maintenance of offshore wind power DC transmission systems.

[0079] Specifically, by dynamically monitoring the temperature and current distribution of each connection terminal, the circulation rate of the cooling medium can be adjusted in a timely manner to meet the thermal management requirements under different operating conditions, thus ensuring the efficient and stable operation of the converter in various environments.

[0080] The internal section of the series terminal output line 41 is designed for medium voltage 50kV. The contact position with the shell 10 is the key point, and its insulation level is 50kV, which reduces the difficulty of insulation manufacturing. Depending on the external wiring, the output line section can be selected with medium voltage insulation of 50kV or high voltage insulation of 500kV.

[0081] In some embodiments, the length of the series terminal output line 41 is greater than the length of the first discrete AC port 43, the length of the first discrete AC port 43 is greater than the length of the second discrete AC port 44, and the length of the second discrete AC port 44 is greater than the length of the series terminal input line 42.

[0082] The distance 'a' between the end of the series terminal outlet 41 furthest from the housing 10 and the end of the series terminal inlet 42 furthest from the housing 10, and the distance 'b' between the end of the first discrete AC port 43 furthest from the housing 10 and the end of the second discrete AC port 44 furthest from the housing 10, satisfy the following condition: 1.5 ≤ a / b ≤ 3. This arrangement reduces the difficulty of insulation and optimizes the insulation effect.

[0083] like Figure 1 , Figure 2 as well as Figures 8 to 10As shown, in this embodiment, the diameter of the series terminal lead 41 gradually increases from near the housing 10 to far away from the housing 10. This design effectively improves the current carrying capacity of the series terminal lead 41 while ensuring that the insulation distance between the series terminal lead 41 and the housing 10 remains within a safe range under high-voltage conditions. By gradually increasing the diameter of the series terminal lead 41 along the direction from the housing 10 to the outside, it better adapts to the distribution characteristics of the electric field, optimizes the current density distribution, reduces the possibility of corona discharge, and thus improves the overall operational stability and safety of the converter.

[0084] In addition, this asymmetrical diameter design also helps to reduce the burden on the cooling system, because the larger diameter part can provide a larger heat dissipation area, which helps to dissipate heat quickly and ensures that the converter can still maintain good temperature control when operating at high power.

[0085] Specifically, this tapered-diameter outgoing line device can be coordinated with other asymmetric design features of the converter to achieve compactness and efficient heat dissipation.

[0086] The diameters of the series terminal inlet 42, the first discrete AC port 43, and the second discrete AC port 44 gradually increase from the direction closest to the housing 10 to the direction furthest from the housing 10.

[0087] like Figure 1 , Figure 2 as well as Figures 8 to 10 As shown, in this embodiment, the plane passing through the center line of the series-connected outgoing line 41 and the center line of the series-connected incoming line 42 is designated as the first preset plane, and the plane passing through the center line of the first discrete AC port 43 and the center line of the second discrete AC port 44 is designated as the second preset plane. The first and second preset planes are set perpendicularly. This asymmetrical outgoing line layout strategy makes full use of the internal space of the converter structure while reducing the insulation difficulty of critical locations. This layout ensures the insulation safety of the high-voltage outgoing lines, and further reduces the size of the equipment by making reasonable use of the space of the converter structure, making it more compact in structure. Therefore, in the offshore wind power DC transmission scenario, it can effectively save installation area and weight, reduce the construction cost of offshore converter stations, and improve the overall efficiency and reliability of offshore wind farms.

[0088] Of course, this vertical layout is not the only way to achieve this. Depending on the different usage environments and requirements, the angle between the first and second preset surfaces can also be adjusted appropriately to achieve the best insulation and heat dissipation effects. This design concept provides a more flexible and efficient converter structure option for offshore wind power DC transmission systems.

[0089] It should be noted that the included angle between the first preset surface and the second preset surface can be between 75° and 115°.

[0090] like Figure 1 , Figure 2 as well as Figures 8 to 10 As shown, in this embodiment, the length of the series-connected output line 41 is greater than the length of the series-connected input line 42, the length of the series-connected output line 41 is greater than the length of the first discrete AC port 43, and the length of the series-connected output line 41 is greater than the length of the second discrete AC port 44. This asymmetric design fully utilizes the internal space layout of the converter structure. Especially when the high-voltage output line is located in the middle of the converter, it effectively optimizes the design of key insulation components, reduces insulation difficulty, and ensures safe and reliable electrical performance. By extending the length of the series-connected output line 41, not only is the internal space of the converter structure effectively utilized, but the insulation treatment of the high-voltage output line is also simplified without affecting the overall electrical characteristics. This significantly reduces the size and weight of the converter while ensuring safe equipment operation, thereby lowering the construction and operation costs of the offshore wind power DC transmission system.

[0091] Of course, the specific length ratios of the series terminal output line 41, the series terminal input line 42, the first discrete AC port 43, and the second discrete AC port 44 can be flexibly adjusted according to actual working conditions and design requirements to achieve the best insulation and cooling effect.

[0092] Specifically, the offshore wind turbine is connected to an isolation transformer after two stages of AC / DC and DC / AC conversion. The voltage is then stepped up in series by a subsequent AC / DC / DC converter. The voltage between the series output line 41 and the series input line 42 is the port voltage, while the series output line 41 is the bus voltage. The voltage between the series output line 41 and the series input line 42 can be selected as 50kV DC, and the voltage between the series output line 41 and the series input line 42 can be selected as 500kV DC. The wind turbine's power is then transmitted to the onshore converter station and connected to the power grid via 500kV DC.

[0093] like Figures 1 to 7 As shown, in this embodiment, the converter structure also includes a heat dissipation structure 70, which is disposed on the outer wall of the housing 10. The heat dissipation structure 70 is tightly integrated into the outer wall of the housing 10, and the above structure makes full use of the natural wind conditions of the offshore wind farm. When the converter structure is working, the heat generated by the internal converter body 20 is absorbed by the fluorinated liquid with excellent thermal conductivity. As the temperature rises, the fluorinated liquid gradually changes from a liquid state to a gaseous state, forming internal liquid-gas phase change cooling. At this time, the gaseous fluorinated liquid rises to the top of the housing 10, and the heat dissipation structure 70 can cool the housing through the outer wall of the housing 10, thereby reducing the temperature of the gaseous fluorinated liquid inside the housing and causing it to liquefy into fluorinated liquid. This cycle repeats, effectively removing heat.

[0094] This cooling mechanism avoids the need for an additional power source, greatly simplifying the system structure and reducing the complexity and cost of operation and maintenance. By rationally arranging the location and shape of the heat dissipation structure 70, it can adapt to the diverse wind directions and speeds of offshore wind farms. Whether in low wind speeds or stronger winds, it ensures continuous and stable cooling of the converter body, maintaining the normal operation of the equipment and significantly improving the overall thermal management performance and operational stability of the converter.

[0095] like Figures 1 to 7 As shown, in this embodiment, the heat dissipation structure 70 includes a cover and a pipe disposed within the cover. The pipe is connected to the receiving space 11 and is coiled. When the converter operates under high load, the heat generated inside is rapidly absorbed by the fluorinated liquid, causing the fluorinated liquid to change from a liquid state to a gaseous state, i.e., fluorinated gas. Under the influence of natural wind in the offshore wind farm, due to the large heat dissipation area of ​​the heat dissipation structure 70, the fluorinated gas can be rapidly cooled and recondensed into liquid fluorinated liquid. This process does not require the intervention of an external power source and relies entirely on the natural cooling effect of the environment, achieving system self-sufficiency and high reliability. The liquid fluorinated liquid falls under the action of gravity and participates in the cooling cycle of the converter again. The entire cooling system has a compact structure, which not only saves space but also simplifies the maintenance process, making it particularly suitable for the outdoor deployment and long-term operation and maintenance needs of offshore wind power converters.

[0096] Since the heat dissipation structure 70 is at a high potential, it is difficult to supply power. According to the unique wind conditions of offshore wind power, the natural wind conditions can reach the level of 11 m / s. Under certain wind speed conditions, it is possible to use natural air cooling. Two sets of heat dissipation structures 70 can be arranged on both sides of the shell 10, or four sets of heat dissipation structures 70 can be arranged around the shell 10 to meet the heat dissipation requirements of the converter body 20.

[0097] It should be noted that the aforementioned coiled pipe is tightly attached to the outer wall of the housing 10.

[0098] When the converter structure starts up, the electrical energy generated by the wind turbine is transferred to the converter body 20 for power conversion via the first discrete AC port 43 and the second discrete AC port 44. During this process, the converter body 20 is completely immersed in the insulating liquid inside the housing 10, achieving efficient internal cooling through the liquid-gas phase change of the fluorinated liquid. When the equipment is running, the converter body 20, composed of semiconductor devices, generates heat. This heat is absorbed by the insulating liquid, causing the liquid to evaporate. The generated gas flows along the gaps formed with the inner wall of the housing 10, such as the first gap 51 to the sixth gap 56, towards the top of the housing 10. At the top of the housing 10, the gas is cooled back to a liquid state through heat exchange with the natural wind via the heat dissipation structure 70, and then circulates again around the converter body 20, forming a closed cooling cycle.

[0099] This design ensures that the converter can maintain a stable and suitable temperature level during high-power operation. Simultaneously, the asymmetric gap distribution strategy optimizes the internal heat flow distribution, reduces the amount of cooling medium used, and lowers the pressure on ground insulation, thereby achieving effective reduction in equipment size and weight. The series-connected output line 41 and series-connected input line 42 are connected to the converter body 20 and external circuitry, respectively. Maintenance is achieved through the suspension structure 60 above the housing, allowing the entire converter body to be lifted out, simplifying maintenance operations and eliminating the need to disassemble complex internal wiring. This process demonstrates effective thermal management and electrical insulation optimization of the converter structure in offshore wind power DC transmission systems, improving equipment operating efficiency and economy while ensuring the long-term safe and stable operation of offshore wind power projects.

[0100] According to another aspect of this application, a power generation system is provided, including a converter structure, which is the converter structure described above. The converter structure described above has a smaller size and ensures effective insulation. Therefore, the power generation system having the converter structure described above also has the aforementioned advantages.

[0101] Specifically, the aforementioned power generation systems include wind power generation systems, nuclear power generation systems, tidal power generation systems, thermal power generation systems, hydropower generation systems, geothermal power generation systems, or other power generation systems.

[0102] In the description of this invention, it should be understood that "a plurality of" means two or more. Directional terms such as "front, back, up, down, left, right," "horizontal, vertical, horizontal," and "top, bottom" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are used solely for the convenience of describing the invention and simplifying the description. Unless otherwise stated, these directional terms 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, and therefore should not be construed as limiting the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner or outer contours relative to the outline of each component itself.

[0103] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0104] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0105] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A converter structure, characterized in that, include: The housing (10) has an internal accommodating space (11). A converter body (20) is disposed within the accommodating space (11), and there is a gap between the converter body (20) and the inner wall of the housing (10), at least part of the gap is filled with insulating liquid, and the converter body (20) is immersed in the insulating liquid; A supporting insulating element (30) is disposed below the housing (10); The connection terminal (40) passes through the top of the housing (10) and connects to the converter body (20).

2. The converter structure according to claim 1, characterized in that, The gap is present in both the converter body (20) and any inner wall of the housing (10).

3. The converter structure according to claim 1, characterized in that, The housing (10) includes a top wall (12), a bottom wall (13), and a surrounding wall (14). The surrounding wall (14) is located between the top wall (12) and the bottom wall (13). There is a first gap (51) between the converter body (20) and the bottom wall (13), and a second gap (52) between the converter body (20) and the top wall (12). The first gap (51) is smaller than the second gap (52).

4. The converter structure according to claim 3, characterized in that, The enclosure (14) includes a first sidewall (141), a second sidewall (142), a third sidewall (143), and a fourth sidewall (144). The first sidewall (141), the second sidewall (142), the third sidewall (143), and the fourth sidewall (144) are connected in sequence. There is a third gap (53) between the converter body (20) and the first sidewall (141), a fourth gap (54) between the converter body (20) and the second sidewall (142), a fifth gap (55) between the converter body (20) and the third sidewall (143), and a sixth gap (56) between the converter body (20) and the fourth sidewall (144). The third gap (53) is smaller than the fifth gap (55), the fourth gap (54) is greater than or equal to the fifth gap (55), and the sixth gap (56) is less than or equal to the third gap (53).

5. The converter structure according to claim 4, characterized in that, The ratio of the sixth gap (56) to the fourth gap (54) is between 0.45 and 0.

75.

6. The converter structure according to claim 4, characterized in that, The ratio between the first gap (51) and the sixth gap (56) is between 0.9 and 1.

1.

7. The converter structure according to claim 4, characterized in that, The sum of the first gap (51), the third gap (53), the fourth gap (54), the fifth gap (55), and the sixth gap (56) is less than the second gap (52).

8. The converter structure according to claim 3, characterized in that, The top wall (12) is detachably disposed from the enclosure wall (14); and / or, the housing (10) further includes a suspension structure (60) connected between the top wall (12) of the housing (10) and the converter body (20).

9. The converter structure according to claim 1, characterized in that, The connection terminal (40) includes a series terminal output line (41), a series terminal input line (42), a first discrete AC port (43), and a second discrete AC port (44). The series terminal output line (41), the series terminal input line (42), the first discrete AC port (43), and the second discrete AC port (44) are all spaced apart. The series terminal output line (41) is located at the center of the converter body (20).

10. The converter structure according to claim 9, characterized in that, The diameter of the series terminal wire (41) gradually increases from the direction closer to the housing (10) to the direction farther away from the housing (10).

11. The converter structure according to claim 9, characterized in that, The plane passing through the center line of the series terminal outlet (41) and the center line of the series terminal inlet (42) is set as the first preset plane, and the plane passing through the center line of the first discrete AC port (43) and the center line of the second discrete AC port (44) is set as the second preset plane. The first preset plane and the second preset plane are set perpendicularly.

12. The converter structure according to claim 9, characterized in that, The length of the series terminal output line (41) is greater than the length of the series terminal input line (42), the length of the series terminal output line (41) is greater than the length of the first discrete AC port (43), and the length of the series terminal output line (41) is greater than the length of the second discrete AC port (44).

13. The converter structure according to claim 1, characterized in that, The converter structure also includes a heat dissipation structure (70), which is disposed on the outer wall of the housing (10).

14. The converter structure according to claim 13, characterized in that, The heat dissipation structure (70) includes a cover and a pipe disposed in the cover. The pipe is connected to the receiving space (11) and is coiled around the cover.

15. A power generation system, comprising a converter structure, characterized in that, The converter structure is the converter structure according to any one of claims 1 to 14.

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