Converter structure and power generation system having the same

Abstract

The application provides a converter structure and a power generation system with the same, wherein the converter structure comprises: a shell, an internal part of the shell having a containing space; a converter body, arranged in the containing space, a gap being formed between the converter body and an inner wall of the shell, at least part of the gap being filled with an insulating liquid, the converter body being immersed in the insulating liquid; a supporting insulating piece, arranged below the shell; and a connecting terminal, penetrating through a top part of the shell and connected with the converter body. The technical scheme of the application effectively solves the problem of a large volume of an offshore wind power direct current transmission converter in the related art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of converter, in particular to a converter structure and a power generation system with the same. BACKGROUND

[0002] Offshore wind power resources are abundant, and the use of DC transmission to transport wind power is an important trend in offshore wind power development. The series boosting topology of the full DC offshore wind farm is widely concerned due to its simple structure and the absence of an offshore converter station. This topology can significantly reduce the collection and transmission costs. However, the converter unit at a higher potential in the series boosting mode poses a severe challenge to insulation design, especially for ±500kV level DC voltage. The traditional air insulation and water cooling technology results in the need to place the converter valve tower in an indoor valve hall to ensure sufficient insulation distance.

[0003] The limitation of air insulation is its low withstand voltage level, which results in a huge size of the offshore converter station valve hall, for example, the valve hall of ±400kV level is 39m x 60m x 21.5m in size and weighs more than 20,000 tons, while the actual converter valve tower only accounts for a small part of it. This not only increases the cost of offshore wind power projects, but also limits the layout and construction of offshore wind farms. Air insulation is the main factor leading to the large size and heavy weight of offshore converter stations, which has become one of the bottlenecks of offshore wind power development.

[0004] In traditional converter stations, the cooling system of the converter usually adopts forced water cooling, and its complexity and reliability have always been the focus of the industry. For offshore wind power converters, the power supply and power extraction of the heat sink at high potential are more complex, increasing the difficulty of system design. In addition, the cooling system of air insulation is less efficient in dealing with high heat flux semiconductor devices, and additional cooling equipment is needed to assist, which further increases the volume 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 heavy weight of the converter valve tower due to air insulation design, and the complexity of the cooling system caused by the power supply and power extraction of the heat sink at high potential. SUMMARY

[0006] The main purpose of the present application is to provide a converter structure and a power generation system with the same, to solve the problem of large size of offshore wind power DC transmission converter in the related art.

[0007] In order to achieve the above object, according to one aspect of the present application, a converter structure is provided, comprising: a housing, the inside of the housing having a containing space; a converter body, arranged in the containing space, a gap being formed between the converter body and the inner wall of the housing, at least part of the gap being filled with an insulating liquid, the converter body being immersed in the insulating liquid; a supporting insulating member, arranged below the housing; and a connecting terminal, penetrating through the top of the housing and connected with the converter body.

[0008] Further, the converter body has a gap with any inner wall of the housing.

[0009] Further, the housing comprises a top wall, a bottom wall and a surrounding wall, the surrounding wall being arranged between the top wall and the bottom wall, the converter body having a first gap with the bottom wall and a second gap with the top wall, the first gap being smaller than the second gap.

[0010] Further, the surrounding wall comprises a first side wall, a second side wall, a third side wall and a fourth side wall, the first side wall, the second side wall, the third side wall and the fourth side wall being connected in sequence, the converter body having a third gap with the first side wall, a fourth gap with the second side wall, a fifth gap with the third side wall and a sixth gap with the fourth side wall, the third gap being smaller than the fifth gap, the fourth gap being greater than or equal to the fifth gap, and the sixth gap being smaller than or equal to the third gap.

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

[0012] Further, the ratio of the first gap to the sixth gap is between 0.9 and 1.1.

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

[0014] Further, the top wall and the surrounding wall are arranged separately, and / or the housing further comprises a suspension structure, the suspension structure being connected between the top wall of the housing and the converter body.

[0015] Further, the connecting terminal comprises a series terminal outgoing line, a series terminal incoming line, a first discrete AC port and a second discrete AC port, the series terminal outgoing line, the series terminal incoming line, the first discrete AC port and the second discrete AC port being arranged at intervals, and the series terminal outgoing line being located at the center of the converter body.

[0016] Further, the diameter of the series terminal outgoing line gradually increases from the direction close to the housing to the direction away from the housing.

[0017] Further, a plane passing through the center line of the series terminal outgoing line and the center line of the series terminal incoming line is set as a first preset plane, and a 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 a second preset plane, and the first preset plane and the second preset plane are arranged vertically.

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

[0019] Further, the converter structure further comprises a heat dissipation structure, and the heat dissipation structure is arranged on the outer sidewall of the shell.

[0020] Further, the heat dissipation structure comprises a cover and a pipeline arranged in the cover, the pipeline is in communication with the accommodation space, and the pipeline is arranged in a coiled manner.

[0021] According to another aspect of the present application, a power generation system is provided, comprising the converter structure as described above.

[0022] By the technical scheme of the present application, the shell has an accommodation space inside, the converter body is arranged in the accommodation space, a gap is formed between the converter body and the inner wall of the shell, and the converter body is immersed in the insulating liquid. The support insulating piece is arranged below the shell. The connecting terminal is arranged through the top of the shell and connected with the converter body. By the above arrangement, the converter body is immersed in the insulating liquid inside the shell, effectively solving the insulation problem under high voltage. The insulating liquid provides superior insulation performance than air, greatly shortening the necessary insulation distance, and further reducing the overall volume and weight of the converter. Moreover, since the support insulating piece supports the shell, the shell can be separated from the ground, and thus the air outside the shell can also be insulated, so as to reduce the insulation pressure of the insulating liquid, and such arrangement can reduce the amount of insulating liquid. In addition, the above structure also promotes internal efficient cooling, that is, the insulating liquid not only plays an insulation role, but also takes away the heat generated during the operation of the converter body through liquid-gas phase change natural circulation without the support of an additional power source, improving the self-sufficiency and stability of the system. The support insulating piece arranged below the shell further ensures the insulation requirement of the equipment to the ground, and the connecting terminal ensures the safe and reliable connection of the converter body with the external circuit. Therefore, the technical scheme of the present application effectively solves the problem of large volume of the offshore wind power DC transmission converter in the related art. BRIEF DESCRIPTION OF DRAWINGS

[0023] The accompanying drawings, which form a part of the present application, are intended to provide further understanding of the present application and are incorporated herein for a purpose of explanations of the present application and are not intended as an undue limitation of the application. In the drawings:

[0024] Figure 1 a perspective structural schematic view of an embodiment of the converter structure according to the present application is shown;

[0025] Figure 2 a perspective structural schematic view of another view of the converter structure of Figure 1

[0026] Figure 3 a front schematic view of the converter structure of Figure 1

[0027] Figure 4 a A-A sectional view of the converter structure of Figure 3

[0028] Figure 5 a B-B sectional view of the converter structure of Figure 3

[0029] Figure 6 an exploded structural schematic view of the converter structure of Figure 1

[0030] Figure 7 a structural schematic view at the housing of the converter structure of Figure 6

[0031] Figure 8 a structural schematic view at the converter body of the converter structure of Figure 6

[0032] Figure 9 a front schematic view of the structure at the converter body of Figure 8

[0033] Figure 10 a top schematic view of the structure at the converter body of Figure 9

[0034] wherein the above figures comprise the following reference signs:

[0035] 10, housing; 11, containing space; 12, top wall; 13, bottom wall; 14, surrounding wall; 141, first side wall; 142, second side wall; 143, third side wall; 144, fourth side wall; 20, converter body; 30, support insulation; 40, connection terminal; 41, series end outgoing line; 42, series end incoming line; 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 DESCRIPTION​​​​​​​​​

[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] Further, for the power supply and power taking problems of the high potential heat sink, and the low efficiency of the air insulation cooling system in handling high heat flux density semiconductor devices, the inventors realize that these technical obstacles not only increase the system complexity and maintenance cost, but also restrict the miniaturization and lightweight development of the offshore wind power converter, especially for the construction of offshore wind farms, high cost and space constraints have become key technical bottlenecks.

[0041] In view of the above analysis, the inventors have clearly defined the direction of technical improvement, that is, to seek a new insulation solution that can significantly reduce the volume and weight of the converter, while simplifying the structure of the cooling system and overcoming the complexity of the heat sink power supply under high potential.

[0042] Specifically, as shown in Figures 1 to 7 In this embodiment, the converter structure includes a shell 10, a converter body 20, a support insulation 30, and a connection terminal 40. The inside of the shell 10 has a containing space 11. The converter body 20 is arranged in the containing space 11, and there is a gap between the converter body 20 and the inner wall of the shell 10, at least part of the gap is filled with insulation liquid, and the converter body 20 is immersed in the insulation liquid. The support insulation 30 is arranged below the shell 10. The connection terminal 40 passes through the top of the shell 10 and is connected with the converter body 20.

[0043] The technical scheme of the embodiment is applied, the inside of the shell 10 has a containing space 11, the converter body 20 is arranged in the containing space 11, there is a gap between the converter body 20 and the inner wall of the shell 10, and the converter body 20 is immersed in the insulating liquid. The supporting insulating piece 30 is arranged below the shell 10. The connecting terminal 40 is arranged through the top of the shell 10 and connected with the converter body 20. Through the above arrangement, the converter body 20 is immersed in the insulating liquid in the inside of the shell 10, effectively solving the insulation problem under high voltage. The insulating liquid provides superior insulation performance than air, greatly shortening the necessary insulation distance, and further reducing the overall volume and weight of the converter. Moreover, the shell 10 is supported by the supporting insulating piece 30, so that the shell 10 is separated from the ground, and the air outside the shell 10 can also be insulated, thereby reducing the insulation pressure of the insulating liquid. Such an arrangement can reduce the amount of insulating liquid. In addition, the above structure also promotes internal efficient cooling, that is, the insulating liquid not only plays an insulating role, but also takes away the heat generated during the operation of the converter body through liquid-gas phase change natural circulation without the support of an additional power source, thereby improving the self-sufficiency and stability of the system. The supporting insulating piece 30 arranged below the shell 10 further ensures the insulation requirement of the equipment to the ground, and the connecting terminal 40 ensures the safe and reliable connection of the converter body 20 and the external circuit. Therefore, the technical scheme of the embodiment effectively solves the problem of large volume of the offshore wind power direct current transmission converter in the related art.

[0044] The technical scheme of the current insulation mode of the converter includes gas insulation and liquid immersion insulation. If the volume of the converter body is set as a x b x c, for a 500-kilovolt-level converter, the insulation distance of the gas insulation is about 5 meters, and the volume of the valve hall is a x b x c + 100 x (ab + bc + ac) + 1000 cubic meters. The insulation distance of the liquid immersion insulation is about 0.5 meters, and the volume of the equipment is a x b x c + ab + bc + ac + 1 cubic meter.

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

[0046] Compared in terms of insulation distance and insulation volume, the technical scheme of the present application has great advantages. Compared with the liquid immersion insulation, the present application can save up to 90% of the amount of fluorinated liquid.

[0047] It should be noted that the above-mentioned insulating liquid is fluorinated liquid. The fluorinated liquid provides internal insulation from the converter body 20 to the top wall 12, and the insulation level is 50 kilovolts or above.

[0048] The support insulation 30 achieves ground insulation, and the insulation level is 500 kV or above 500 kV.

[0049] Specifically, the converter structure significantly improves the problems of large volume, heavy weight and complex cooling system faced by the converter in the process of offshore wind power DC transmission. When the converter structure is working, the converter body 20 is completely immersed in the insulating liquid inside the shell 10. Through the high insulation performance of the insulating liquid, the insulation distance between the internal elements of the converter body 20 and the shell 10 is greatly reduced, which effectively compresses the overall volume of the converter structure and reduces the weight. In the process of power conversion, the cooling characteristics of the insulating liquid in the two-phase conversion process provide efficient internal cooling for the converter body 20, without the need for an additional power source, greatly simplifying the cooling system and enhancing the adaptive cooling capability of the system. The external support insulation 30 not only stably supports the converter structure, but also provides the necessary external insulation in a high voltage environment, ensuring electrical safety. The connection terminal 40, by its design through the top of the shell 10 during equipment operation, not only ensures the reliable connection of the converter body 20 and the external circuit, but also allows 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 the optimization of the 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 operation efficiency and reliability of the system.

[0051] This design can better adapt to the offshore environment and reduce the demand for space. At the same time, through the natural circulation cooling method, the energy consumption in the process of power conversion is reduced, realizing a more economical and environmentally friendly offshore wind power DC transmission solution.

[0052] From the above, the inventors have clearly defined the technical improvement goal of reducing the volume and weight of the converter structure and simplifying the cooling system structure. After defining the improvement goal, 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 application scenarios of various insulation technologies and realized that liquid insulation medium is a potential choice for reducing the size of the valve hall and reducing weight due to its high insulation performance and compactness. Compared with air insulation, liquid insulation medium such as fluorinated liquid can provide the same insulation effect at a shorter distance, which creates the possibility of placing 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 comprises a top wall 12, a bottom wall 13, and a surrounding wall 14 located between the top wall 12 and the bottom wall 13. The converter body 20 has a first gap 51 with the bottom wall 13 and a second gap 52 with the top wall 12, and the first gap 51 is smaller than the second gap 52. The housing 10 comprises a top wall 12, a bottom wall 13, and a surrounding wall 14 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 converter body 20 has a first gap 51 with the bottom wall 13 and a second gap 52 with the top wall 12, and the first gap 51 is smaller than the second gap 52. This asymmetric design aims to optimize the cooling efficiency and insulation performance of the converter. Through the smaller first gap 51, the circulation speed of the immersed cooling medium at the bottom of the converter body 20 is improved, and the cooling effect of the heat source is strengthened. At the same time, the larger second gap 52 ensures sufficient insulation distance between the top of the converter body 20 and the external environment, improving the electrical safety. In addition, this design also helps to reduce the overall weight of the housing 10, as the amount of cooling medium used is reduced, and the requirement for the structural strength of the housing 10 is also reduced, making the overall device more lightweight and efficient, especially suitable for DC transmission systems for offshore wind power, which requires higher reliability and economy of the device.

[0059] As Figures 1 to 5As shown, in the present embodiment, the enclosing wall 14 comprises a first side wall 141, a second side wall 142, a third side wall 143, and a fourth side wall 144, which are connected in sequence. The converter body 20 and the first side wall 141 have a third gap 53 therebetween, the converter body 20 and the second side wall 142 have a fourth gap 54 therebetween, the converter body 20 and the third side wall 143 have a fifth gap 55 therebetween, and the converter body 20 and the fourth side wall 144 have a sixth gap 56 therebetween. 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 smaller than or equal to the third gap 53. The enclosing wall 14 is formed by the first side wall 141, the second side wall 142, the third side wall 143, and the fourth side wall 144 connected in sequence, forming a closed space surrounding the converter body 20. The key of this design lies in the size difference of the gaps between the enclosing wall 14 and the converter body 20. Specifically, the third gap 53 between the converter body 20 and the first side wall 141 is smaller than the fifth gap 55 between the converter body 20 and the third side wall 143, while the fourth gap 54 between the converter body 20 and the second side wall 142 is greater than or equal to the fifth gap 55, and the sixth gap 56 between the converter body 20 and the fourth side wall 144 is smaller than or equal to the third gap 53. This asymmetric gap design takes full advantage of the different insulation characteristics of the fluorinated liquid, achieving precise control of the insulation requirements inside 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 side wall 142 and the third side wall 143, to cope with possible electrical fluctuations and stress distribution, ensuring electrical safety.

[0060] In summary, the present embodiment optimizes the gap layout between the enclosing wall 14 and the converter body 20, not only achieving compact design of the device, but also considering electrical safety and economy, embodying the efficiency and rationality of the design.

[0061] As 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 takes full advantage of the characteristics of the internal space 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 reducing costs.

[0067] In the design of the converter under high-voltage environment, it is crucial to reasonably plan the insulation distance at different positions. Through this asymmetric gap design strategy, not only the insulation safety of the key parts is ensured, but also the heat dissipation path of the area with high heat flux density inside the converter structure is optimized, enhancing the reliability and stability of the system. This design can effectively cope with the complex and variable operating conditions of offshore wind power.

[0068] As shown in the figure, Figures 6 to 9 In this embodiment, the top wall 12 and the surrounding wall 14 are detachably arranged. The above design allows the converter structure to be more flexible and convenient to operate during maintenance and repair. Specifically, when it is necessary to inspect or replace the converter body 20 located inside the box, the whole can be lifted out by separating the top wall 12 and the surrounding wall 14, without the need to disassemble the complex internal wiring or rearrange the position of the radiator.

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

[0070] In addition, the independent disassembly of the top wall 12 also makes it possible to upgrade the cooling system of the converter, such as adding more radiators or optimizing the fluorinated liquid circulation path as necessary to adapt to the working requirements of the converter under higher power density. Therefore, this separable top wall design not only enhances the maintenance convenience of the converter.

[0071] In this embodiment, the inside of the converter body 20 is provided with a gas-liquid separation radiator and a power device, and the power device is arranged on the gas-liquid separation radiator.

[0072] Specifically, the gas-liquid separation radiator includes a radiator body, the inside of the radiator body has a avoiding space, and the power device is arranged on the radiator body and passes through the avoiding space. The top of the radiator body is open. The side wall of the radiator body is provided with a liquid inlet. The fluorinated liquid can enter the inside of the radiator body through the liquid inlet and contact the power device. After the gas-liquid two-phase conversion is realized, the gas can be discharged through the top of the radiator body.

[0073] The inside of the radiator body is provided with a plurality of connecting rods, and the plurality of connecting rods are arranged at intervals. The liquid inlet is arranged downwardly. The liquid inlet is arranged on the side wall of the converter body 20 and communicates with the containing space 11. That is, in this case, the top wall is not immersed in the fluorinated liquid.

[0074] As shown in Figures 6 to 9 In this embodiment, the shell 10 further comprises a suspension structure 60 connected between the top wall 12 of the shell 10 and the converter body 20. The suspension structure 60 is connected between the top wall 12 of the shell 10 and the converter body 20, forming 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, the structure allows the whole to be hoisted out without disassembling complex internal wiring, effectively simplifying the operation process and reducing the operation and maintenance cost.

[0075] In addition, the arrangement of the suspension structure 60 also optimizes the spatial layout of the converter, enabling efficient cooling and insulation in limited space while taking into account the compactness and operability of the equipment, embodying the comprehensiveness and practicality of the design.

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

[0077] As shown in Figure 1 , Figure 2 and Figures 8 to 10 In this embodiment, the connecting terminal 40 comprises a series end outlet 41, a series end inlet 42, a first discrete AC port 43 and a second discrete AC port 44, and the series end outlet 41, the series end inlet 42, the first discrete AC port 43 and the second discrete AC port 44 are arranged at intervals. The series end outlet 41 is located at the center of the converter body 20. The series end outlet 41 is positioned at the center of the converter body 20, and the above structure not only optimizes the internal electrical layout, but also makes full use of the space inside the converter structure, effectively alleviating the difficulty of insulation treatment of the high-voltage outlet at the key position.

[0078] In the working process, when the current enters the converter body 20 through the series end incoming line 42, the current path is designed to be more compact due to the central location of the series end outgoing line 41, which promotes the uniform distribution of the cooling medium inside the converter, enhances the cooling efficiency, and ensures the stable operation of the semiconductor devices under high load. At the same time, the first discrete AC port 43 and the second discrete AC port 44 are distributed on the outer edge, and this dispersed layout helps to balance the overall thermal load distribution of the device, ensures consistent temperature control of each part, prevents local overheating, and improves the thermal management and reliability of the converter. The overall structure of the converter is more compact, the space utilization is significantly improved, and at the same time, this layout simplifies the maintenance and repair process of the device, improving the operation and maintenance convenience of the offshore wind power DC transmission system.

[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 needs under different working conditions, ensuring the efficient and stable operation of the converter under various environments.

[0080] The internal section of the series end outgoing line 41 is designed as medium voltage 50kV, and the contact position with the shell 10 is the key point, with an insulation level of 50kV, thereby reducing the difficulty of insulation manufacturing, and the outgoing line section can select medium voltage insulation 50kV or high voltage insulation 500kV according to the different external connection lines.

[0081] In some embodiments, the length of the series end outgoing 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 end incoming line 42.

[0082] The distance a between the end of the series end outgoing line 41 away from the shell 10 and the end of the series end incoming line 42 away from the shell 10, and the distance b between the end of the first discrete AC port 43 away from the shell 10 and the end of the second discrete AC port 44 away from the shell 10 satisfy: 1.5≤a / b≤3. The above setting can reduce the difficulty of insulation and optimize the effect of insulation.

[0083] As Figure 1 , Figure 2 and Figures 8 to 10As shown, in this embodiment, the diameter of the series-end outgoing line 41 gradually increases from the direction close to the shell 10 to the direction away from the shell 10. The above design can effectively improve the current flow capacity of the series-end outgoing line 41, while ensuring that the insulation distance between the series-end outgoing line 41 and the shell 10 remains within a safe range in a high-voltage environment. By gradually increasing the diameter of the series-end outgoing line 41 from the shell 10 to the outside, the distribution characteristics of the electric field can be better adapted, the current density distribution can be optimized, and the possibility of corona discharge can be reduced, thereby improving the operation stability and safety of the entire converter.

[0084] In addition, this asymmetric diameter design also helps to reduce the burden on the cooling system, as the larger diameter part can provide a larger heat dissipation area, helping to quickly dissipate heat energy and ensuring that the converter can still maintain good temperature control during high-power operation.

[0085] Specifically, this gradually changing diameter outgoing line device can coordinate with other asymmetric design features of the converter to achieve the compactness and efficient heat dissipation of the device.

[0086] As shown, in this embodiment, the diameter of the series-end outgoing line 41 gradually increases from the direction close to the shell 10 to the direction away from the shell 10. The above design can effectively improve the current flow capacity of the series-end outgoing line 41, while ensuring that the insulation distance between the series-end outgoing line 41 and the shell 10 remains within a safe range in a high-voltage environment. By gradually increasing the diameter of the series-end outgoing line 41 from the shell 10 to the outside, the distribution characteristics of the electric field can be better adapted, the current density distribution can be optimized, and the possibility of corona discharge can be reduced, thereby improving the operation stability and safety of the entire converter.

[0087] As shown in FIG. 1, the series-end outgoing line 41 is connected to the series-end incoming line 42, and the series-end outgoing line 41 and the series-end incoming line 42 are connected to the first discrete AC port 43 and the second discrete AC port 44. Figure 1 , Figure 2 and Figures 8 to 10 As shown, in this embodiment, a plane passing through the center line of the series-end outgoing line 41 and the center line of the series-end incoming line 42 is defined as a first preset plane, and a 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 defined as a second preset plane, and the first preset plane and the second preset plane are arranged vertically. This asymmetric design of the outgoing line layout strategy makes full use of the internal space of the converter structure, while reducing the insulation difficulty of the key position. Such a layout can ensure the insulation safety of the high-voltage outgoing line, while reasonably utilizing the space of the converter structure, further reducing the volume of the device, making it more compact in structure, thereby effectively saving installation area and weight in the offshore wind power DC transmission scenario, reducing the construction cost of the offshore converter station, and improving the overall efficiency and reliability of the offshore wind farm.

[0088] Of course, this vertically arranged layout is not the only implementation, and the angle between the first preset plane and the second preset plane can be adjusted appropriately according to different use environments and requirements to achieve the best insulation and heat dissipation effect. Such a design concept provides a more flexible and efficient converter structure selection 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] As shown in Figure 1 , Figure 2 and Figures 8 to 10 , in the present embodiment, the length of the series terminal outgoing line 41 is greater than the length of the series terminal incoming line 42, the length of the series terminal outgoing line 41 is greater than the length of the first discrete AC port 43, and the length of the series terminal outgoing line 41 is greater than the length of the second discrete AC port 44. The above-mentioned asymmetric design makes full use of the internal space layout of the converter structure, especially in the case of arranging the high-voltage outgoing line in the middle position of the converter, which can effectively optimize the design of the key insulation part, reduce the insulation difficulty, and at the same time ensure the safety and reliability of the electrical performance. By lengthening the length of the series terminal outgoing line 41, not only the internal space of the converter structure is effectively utilized, but also the insulation treatment of the high-voltage outgoing line is simplified without affecting the overall electrical characteristics, thereby significantly reducing the volume and weight of the converter while ensuring the safety of equipment operation, and reducing the construction and operation and maintenance cost of the offshore wind power DC transmission system.

[0091] Of course, the specific length ratio of the series terminal outgoing line 41, the series terminal incoming line 42, and the first discrete AC port 43 and the second discrete AC port 44 can be flexibly adjusted according to the actual working condition and design requirement to achieve the best insulation and cooling effect.

[0092] Specifically, the offshore wind turbine and the isolation transformer connected after the AC / DC and DC / AC two-stage conversion are connected through the rear-stage AC / DC / DC converter for series voltage boosting, the port voltage is between the series terminal outgoing line 41 and the series terminal incoming line 42, the series terminal outgoing line 41 is the bus voltage, the series terminal outgoing line 41 and the series terminal incoming line 42 can be selected as 50kV DC, the series terminal outgoing line 41 can be selected as 500kV DC, and the wind turbine electrical energy is sent to the shore converter station through 500kV DC to access the power grid.

[0093] As shown in Figures 1 to 7 , in the present embodiment, the converter structure further comprises a heat dissipation structure 70 arranged on the outer side wall of the shell 10. The heat dissipation structure 70 is closely integrated with the outer side wall of the shell 10, and the above-mentioned structure makes full use of the natural wind power condition 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 heat conduction performance, and as the temperature rises, the fluorinated liquid gradually changes from liquid to gas to form internal liquid-gas phase change cooling. At this time, the gaseous fluorinated liquid rises to the top of the shell 10, and the heat dissipation structure 70 can cool the shell through the outer side wall of the shell 10, thereby reducing the temperature of the gaseous fluorinated liquid inside the shell and liquefying it into fluorinated liquid, which circulates repeatedly to effectively take away the heat.

[0094] This cooling mechanism avoids the need for an additional power source, greatly simplifies the structure of the system, and also reduces the complexity and cost of operation and maintenance. By reasonably arranging the position and form of the heat dissipation structure 70, it can adapt to the diversification of wind direction and wind speed changes in offshore wind farms. Whether in weather with low wind speed or in a more powerful wind environment, it can ensure that the converter body is continuously and stably cooled, maintain the normal operating state of the equipment, and thus significantly improve the overall thermal management performance and operating stability of the converter.

[0095] As shown in Figures 1 to 7 In this embodiment, the heat dissipation structure 70 includes a cover and a pipe arranged in the cover, the pipe is in communication with the containing space 11, and the pipe is arranged in a coil. When the converter is working in a high load state, the heat generated inside is quickly absorbed by the fluorinated liquid, which causes the fluorinated liquid to change from a liquid state to a gaseous state, i.e., fluorinated gas. Under the action of natural wind in the offshore wind farm, due to the large heat dissipation area of the heat dissipation structure 70, the heat dissipation structure 70 can quickly cool and re-condense the fluorinated gas into liquid fluorinated liquid. This process does not require the intervention of an external power source and completely relies on the natural cooling effect of the environment, achieving self-sufficiency and high reliability of the system. The liquid fluorinated liquid falls under the action of gravity and participates in the cooling cycle of the converter again. The entire cooling system structure is compact, not only saving space but also simplifying the maintenance process, and is particularly suitable for the outdoor deployment and long-term operation and maintenance requirements of offshore wind converter.

[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 11 meters / second, and under certain wind speed conditions, it meets the conditions for natural wind cooling. Two groups of heat dissipation structures 70 can be arranged on both sides of the shell 10, or four groups of heat dissipation structures 70 can be arranged around the shell 10 to meet the heat dissipation needs of the converter body 20.

[0097] It should be noted that the pipe arranged in a coil is closely attached to the outer wall of the shell 10.

[0098] When the converter structure starts to operate, the electric energy generated by the wind turbine is transmitted to the converter body 20 via the first discrete AC port 43 and the second discrete AC port 44 for power conversion. In this process, the converter body 20 is completely immersed in the insulating liquid inside the shell 10, and efficient internal cooling is achieved through the liquid-gas phase change of the fluorinated liquid. When the device operates, the converter body 20 composed of semiconductor devices and the like generates heat, which is absorbed by the insulating liquid and causes the liquid to evaporate, generating gas that flows to the top of the shell 10 along the gaps formed with the inner wall of the shell 10, such as the first gap 51 to the sixth gap 56. At the top of the shell 10, the gas is cooled back to the liquid state by the heat exchange action of the heat dissipation structure 70 with the natural wind, and then recirculates around the converter body 20, forming a closed cooling cycle.

[0099] This design ensures that the converter can stably maintain a suitable temperature level during high-power operation, while optimizing the distribution of internal heat flow through an asymmetric gap distribution strategy, reducing the amount of cooling medium used, and reducing the pressure on the ground insulation, thereby effectively reducing the volume and weight of the device. The series end outgoing line 41 and the series end incoming line 42 are connected to the converter body 20 and the external circuit respectively, and the maintenance of the device is achieved through the suspension structure 60 above the shell, allowing the converter body to be lifted out as a whole, simplifying the maintenance work and eliminating the need to disassemble complex internal wiring. This process demonstrates the effective thermal management and electrical insulation optimization of the converter structure in the offshore wind power DC transmission system, improving the operating efficiency and economy of the device, while ensuring the long-term safe and stable operation of offshore wind power projects.

[0100] According to another aspect of the present application, a power generation system is provided, comprising a converter structure as described above. The converter structure as described above is small in size and can ensure the insulation effect of the converter structure. Therefore, the power generation system with the converter structure as described above also has the advantages as described above.

[0101] Specifically, the power generation system as described above includes a wind power generation system, a nuclear power generation system, a tidal power generation system, a thermal power generation system, a hydroelectric power generation system, a geothermal power generation system, or other power generation systems.

[0102] In the description of the application, it should be understood that "a plurality of" means two or more than two. The orientation words such as "front, back, upper, lower, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" and the like indicated by the orientation or position relationship shown in the drawings are usually based on the orientation or position relationship shown in the drawings, only for the convenience of describing the application and simplifying the description, without making the opposite statement, these orientation words do not indicate and imply that the device or element indicated must have a particular orientation or be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the scope of protection of the application; The orientation words "inner, outer" refer to the inner and outer of the contour of each component itself.

[0103] For the convenience of description, spatial relative terms such as "on", "above", "upper surface", "upper", etc. can be used herein to describe the spatial position relationship of one device or feature with other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation of the device described in the drawings. For example, if the device in the drawing is inverted, the device described as "above" or "on" other devices or structures will be positioned "below" or "under" other devices or structures. Therefore, the exemplary term "above" can include both "above" and "below" orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative description used herein is interpreted accordingly.

[0104] In addition, it should be noted that the use of "first", "second" and the like words to limit parts, only for the convenience of corresponding parts, such as no other declaration, the above words have no special meaning, therefore, it cannot be understood as a limitation on the scope of protection of the application.

[0105] The above only describes the preferred embodiments of the application and is not intended to limit the application. For those skilled in the art, the application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A converter structure, characterized by The application relates to a converter housing. The housing (10) has an accommodating space (11) inside; a converter body (20) is arranged in the accommodating space (11), a gap is formed 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 member (30) is arranged below the housing (10); a connecting terminal (40) penetrates the top of the housing (10) and is connected with the converter body (20); the housing (10) comprises 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), a second gap (52) is formed between the converter body (20) and the top wall (12), and the first gap (51) is smaller than the second gap (52); the surrounding wall (14) comprises a first side wall (141), a second side wall (142), a third side wall (143) and a fourth side wall (144), the first side wall (141), the second side wall (142), the third side wall (143) and the fourth side wall (144) are sequentially connected, a third gap (53) is formed between the converter body (20) and the first side wall (141), a fourth gap (54) is formed between the converter body (20) and the second side wall (142), a fifth gap (55) is formed between the converter body (20) and the third side wall (143), a sixth gap (56) is formed 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 smaller than or equal to the third gap (53). The converter body (20) has the gap with any inner wall of the housing (10). The ratio of the sixth gap (56) to the fourth gap (54) is between 0.45 and 0.

75. The ratio between the first gap (51) and the sixth gap (56) is between 0.9 and 1.

1. 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 smaller than the second gap (52). The top wall (12) and the surrounding wall (14) are arranged in a detachable mode; and / or the housing (10) further comprises a suspension structure (60) connected between the top wall (12) of the housing (10) and the converter body (20).

2. The converter structure according to claim 1, characterized in that ​ 3. The converter structure according to claim 1, characterized in that ​ 4. The converter structure according to claim 1, characterized in that ​ 5. The inverter structure of claim 1, wherein ​ 6. The inverter structure of claim 1, wherein ​ 7. The inverter structure of claim 1, wherein The connecting terminal (40) comprises a series end outgoing line (41), a series end incoming line (42), and a first discrete AC port (43) and a second discrete AC port (44), the series end outgoing line (41), the series end incoming line (42), the first discrete AC port (43), and the second discrete AC port (44) are all arranged at intervals, and the series end outgoing line (41) is located at the center of the converter body (20).

8. The inverter structure according to claim 7, characterized in that The diameter of the series end outgoing line (41) gradually increases from the direction close to the shell (10) to the direction away from the shell (10).

9. The inverter structure according to claim 7, characterized by A plane passing through the center line of the series end outgoing line (41) and the center line of the series end incoming line (42) is defined as a first preset plane, and a 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 defined as a second preset plane, and the first preset plane and the second preset plane are arranged vertically.

10. The inverter structure of claim 7, wherein, The length of the series end outgoing line (41) is greater than the length of the series end incoming line (42), the length of the series end outgoing line (41) is greater than the length of the first discrete AC port (43), and the length of the series end outgoing line (41) is greater than the length of the second discrete AC port (44).

11. The inverter structure of claim 1, wherein, The converter structure further comprises a heat dissipation structure (70) arranged on the outer wall of the shell (10).

12. The converter structure according to claim 11, characterized in that The heat dissipation structure (70) comprises a cover and a pipeline arranged in the cover, the pipeline is in communication with the accommodating space (11), and the pipeline is arranged in a coiled manner.

13. A power generation system comprising a converter structure, characterized by The converter structure is any one of the converter structures in claims 1-12.

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