A wireless power supply system for offshore superconducting wind turbines

Abstract

This invention discloses a wireless power supply system for offshore superconducting wind turbines, relating to the field of offshore wind power generation technology. It includes a housing and a wireless power supply device for a vacuum Dewar, a superconducting motor, and a rotary flux pump housed within the housing. The vacuum Dewar contains a rotating cooling device. The outer rotor and inner rotor of the rotary flux pump rotate at different speeds. A permanent magnet on the outer rotor induces a DC output voltage on the high-temperature superconducting stator strip of the inner rotor, providing DC current to the excitation winding of the superconducting motor, forming a magnetic field, and inducing an output voltage at the armature winding of the superconducting motor. This invention employs non-contact rotary excitation, eliminating the need for traditional current leads, thus avoiding heat leakage caused by bridging current leads between room temperature and low-temperature environments, as well as the Joule heat generated by the leads themselves. Furthermore, placing the rotary excitation outer rotor at room temperature effectively avoids frictional and conductive heat from the mechanical drive shaft, further reducing cooling requirements.

Description

Technical Field

[0001] This invention relates to the field of offshore wind power generation technology, and in particular to a wireless power supply system for offshore superconducting wind turbines. Background Technology

[0002] Compared to economically exploitable onshore wind resources, offshore wind energy boasts advantages such as higher reserves, higher wind speeds, less dust, less turbulence, better quality, and no environmental pollution. Wind speeds in open sea areas are 30%-40% higher than onshore wind speeds. Compared to onshore wind power, offshore wind power resources offer 20%-40% higher energy efficiency and 50%-70% larger power generation capacity. It also features advantages such as not occupying land resources, stable operation, and zero dust emissions, making it suitable for large-scale development. For example, a 1.5 MW wind turbine installed along the Zhejiang coast can generate 1800-2000 hours of electricity annually onshore, while offshore wind power can generate 2000-2300 hours, resulting in an additional 450,000 kilowatt-hours of electricity per year.

[0003] The aforementioned advantages have made offshore wind power a major trend in wind energy development. With the large-scale development of nearshore wind farms, the trend of large-capacity single units in deep-sea wind power is inevitable and represents the latest frontier in global wind power development.

[0004] Current research on offshore wind power focuses on the trend towards larger single-unit capacities in deep-sea areas, leading to increased turbine weight and size, and increased difficulty in offshore transportation, installation, operation, and maintenance. To ensure efficient, low-cost, and reliable operation of wind farms / wind turbine units, a suitable method is needed. Using high-temperature superconducting (HTS) motors to replace existing motors can significantly increase power density, substantially reduce size and weight, and lower wind power costs, thus gaining widespread adoption in the offshore wind power sector.

[0005] However, considering the current transmission characteristics of second-generation high-temperature superconducting tapes, in order to maintain the constant current mode of the high-temperature superconducting magnet, an external power supply is usually used to charge the magnet through copper current leads. This is a considerable heat source for the cooling system. Traditional current leads are connected between the cryogenic Dewar and room temperature. The huge temperature difference creates a heat leakage source at the current leads. In addition, the Joule heat generated by the joint resistance, magnetic flux creep, and AC losses during excitation operation creates an additional heat source, which puts a heavy burden on the refrigeration equipment and affects the safe and stable operation of the equipment.

[0006] To address these issues, those skilled in the art have developed various technical solutions, such as the invention patent entitled "A Method for Applying Wireless Power Transmission and Magnetic Drive to Superconducting Motors," application number "201710034310.9." In this invention, the frequency converter converts industrial frequency power into radio frequency power, which is transmitted through a transmitting coil. A receiving coil, with its resonant frequency matching that of the transmitting coil, induces an alternating current through coupling resonance. This current is then supplied to the stator coils via a rectifier-inverter unit to generate a rotating magnetic field. The rotor windings generate an induced current, forming a magnetic field that interacts with the stator's rotating magnetic field to produce rotation. Torque is transmitted to the external load via a magnetic drive device. This invention utilizes wireless power transmission technology to transmit electricity to the stator coils, generating a rotating magnetic field in the motor's air gap. The rotor's output torque is then transmitted to the load via a magnetic drive device. This effectively avoids heat leakage loads caused by current feeders and mechanical drive shafts, reducing the cooling requirements of the refrigerator, decreasing the cost of the refrigeration system and motor operation, optimizing the motor system structure, and resulting in a smaller, more compact overall machine.

[0007] However, this solution requires a frequency converter to convert the mains frequency power to radio frequency power, and a rectifier-inverter unit to rectify the alternating current. This necessitates complex electromagnetic devices and control units, resulting in a complex structure and poor maintainability. Furthermore, the conversion circuit generates a large amount of Joule heat over a long period, which is detrimental to long-term reliable operation.

[0008] Another example is the invention patent titled "A Wireless Excitation System for a Superconducting Motor," application number "202310735554.5," which includes a transmitting coil, a receiving coil, and a superconducting rectifier. The transmitting coil is kept stationary at room temperature, while the receiving coil, the superconducting rectifier, and the superconducting excitation winding in the superconducting motor are kept at low temperature and rotate synchronously. The transmitting and receiving coils are coupled by a magnetic field, and the superconducting rectifier and the superconducting excitation winding are connected in parallel across the receiving coil. During operation, the transmitting coil is driven by an external AC current source, enabling it to transmit magnetic field energy outward using the current magnetic effect, thus inducing an alternating current in the receiving coil. The superconducting rectifier is used to rectify this induced alternating current, thereby generating a DC voltage across the superconducting excitation winding for excitation. This invention effectively eliminates the current leads and rotating parts used for excitation in traditional superconducting motors, improving the efficiency of the superconducting motor and reducing its size, weight, and cost.

[0009] However, in this scheme, the superconducting rectifier is connected in parallel with the excitation winding, and the joint winding generates a heat load, which is not conducive to maintaining the low temperature environment. Furthermore, the superconducting rectifier is used to rectify the induction AC of the excitation winding, which generates heat loss during operation. More cooling capacity is required to maintain the stability of the low temperature environment, resulting in a large cooling demand.

[0010] Therefore, a completely new solution is urgently needed to address the above problems, simplify equipment composition, and reduce heat loss. Summary of the Invention

[0011] The purpose of this invention is to provide a wireless power supply system for offshore superconducting wind turbines, in order to solve the problems existing in the prior art, simplify the equipment composition, and reduce heat loss.

[0012] To achieve the above objectives, the present invention provides the following solution:

[0013] A wireless power supply system for an offshore superconducting wind turbine includes a housing and wireless power supply devices for a vacuum Dewar, a superconducting motor, and a rotary flux pump disposed inside the housing.

[0014] The vacuum Dewar is equipped with a refrigeration device that rotates inside, and the power source for the rotation of the refrigeration device is an offshore wind turbine.

[0015] The superconducting motor includes an armature winding fixedly disposed on the inner wall of the housing and an excitation winding uniformly arranged on the outer periphery of the refrigeration device.

[0016] The rotary flux pump wireless power supply device includes an inner rotor and an outer rotor that are disposed opposite to each other on the inner and outer sides of the vacuum Dewar, and the inner rotor and the outer rotor rotate coaxially with the excitation winding.

[0017] The outer periphery of the inner rotor is provided with a high-temperature superconducting stator strip that is electrically connected to the excitation winding in a one-to-one correspondence; the outer rotor is provided with a permanent magnet on the side facing the inner rotor that corresponds to the high-temperature superconducting stator strip in a one-to-one correspondence.

[0018] The outer rotor and the inner rotor rotate at different speeds. The permanent magnet induces a DC output voltage on the high-temperature superconducting stator strip, which inputs DC current to the excitation winding, forms a magnetic field, and induces an output voltage at the armature winding of the superconducting motor.

[0019] Preferably, the excitation winding is a non-insulated double-pane coil, which is made of second-generation high-temperature superconducting tape YBCO and stainless steel wound on an epoxy resin skeleton.

[0020] Preferably, the high-temperature superconducting stator strips on the inner rotor are wound independently in parallel.

[0021] Preferably, the high-temperature superconducting stator strip is welded to the excitation winding via a lead solder joint.

[0022] Preferably, the annular magnetic yoke of the inner rotor is made of aluminum oxide.

[0023] Preferably, the portion of the vacuum dewar located between the inner and outer rotors is made of G10 composite material.

[0024] Preferably, the refrigeration device is fixedly connected to the offshore wind turbine via a first rotating shaft that extends through the vacuum dewar and the housing.

[0025] Preferably, the vacuum dewar has a support member inside for mounting the refrigeration device, and the refrigeration device is rotatably connected to the support member via a bearing.

[0026] Preferably, it further includes a negative feedback transmission device for monitoring the rotational speed of the first rotating shaft of the fan and adjusting the rotational speed of the outer rotor accordingly.

[0027] Preferably, the negative feedback transmission device includes a monitoring system, a drive motor electrically connected to the monitoring system, a driving gear fixedly disposed at the output end of the drive motor, and a driven gear fixedly connected to the outer rotor.

[0028] The present invention achieves the following technical effects compared to the prior art:

[0029] 1. This invention introduces superconducting flux pump technology, which adopts non-contact rotary excitation. The magnetic flux is injected into the closed coil through non-electrical connection to compensate for the current attenuation of the high-temperature superconducting magnet. It eliminates the need for traditional current leads, thus eliminating the heat leakage source formed by the current lead bridging between room temperature and low temperature environments, as well as the Joule heat generated during the excitation operation itself. This reduces the cooling demand and improves the energy utilization efficiency of the equipment. At the same time, the modular design eliminates structures such as slip rings, optimizes mechanical wear, and reduces the complexity of equipment maintenance.

[0030] 2. Non-contact rotary excitation induces DC output in the high-temperature superconducting stator strip, eliminating the need for a separate rectifier. This simplifies the structure of the superconducting fan equipment, eliminates additional energy consumption, and effectively improves energy utilization.

[0031] 3. The electrical parameters output by the rotary flux pump wireless power supply equipment are DC output, which eliminates the slip rings and brushes in traditional fans, simplifies the rotor structure of superconducting fans, eliminates the mechanical losses of slip rings and brushes, and is more conducive to inspection and maintenance.

[0032] 4. In the internal rotor structure of the rotary flux pump wireless power supply equipment, each high-temperature superconducting stator strip is individually connected to the excitation winding of the superconducting motor, forming a modular design. When one coil fails, the other superconducting coils can still operate reliably.

[0033] 5. The rotary flux pump wireless power supply equipment transfers the rotary excitation outer rotor from the low-temperature Dewar and places it in a room temperature environment, effectively avoiding frictional heat and conduction heat from the mechanical transmission shaft, reducing the cooling demand of the refrigeration unit, and reducing refrigeration costs and operation and maintenance costs.

[0034] 6. The rotary flux pump wireless power supply equipment uses G10 composite material for the Dewar between the inner and outer rotors. G10 material, at the same thickness as traditional insulating materials, possesses excellent insulation performance and high-temperature resistance. Therefore, while maintaining the same electrical performance, its thickness can be reduced, thus decreasing the air gap space occupied between the inner and outer rotors and compressing the air gap. Using G10 composite material effectively reduces the gap between the permanent magnet and the high-temperature superconducting stator strip, increases the magnetic field strength on the high-temperature superconducting stator strip, and improves the excitation current in the high-temperature superconducting double-pancake coil.

[0035] 7. Offshore wind energy is intermittent and fluctuates, causing the rotational speed of the superconducting wind turbine to change continuously. By setting up a negative feedback transmission device to monitor the rotational speed of the offshore wind turbine, the rotational speed of the outer rotor is adjusted to maintain the speed difference between the permanent magnet and the high-temperature superconducting stator tape, so that the traveling wave magnetic field on the high-temperature superconducting stator tape remains stable, thereby ensuring that the excitation current input of the superconducting wind turbine is constant. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the wireless power supply system for offshore superconducting wind turbines disclosed in this invention.

[0038] Figure 2 for Figure 1 A schematic diagram of an inner rotor and an outer rotor;

[0039] Figure 3 for Figure 1 Another structural schematic diagram of the inner and outer rotors;

[0040] The components are as follows: 1. Liquid nitrogen input pipe; 2. First rotating shaft; 3. Housing; 4. Support component; 5. Refrigeration device; 6. Armature winding; 7. Vacuum Dewar; 8. Excitation winding; 9. Lead solder sheet welding head; 10. Drive gear; 11. Drive motor; 12. High-temperature superconducting stator strip; 13. Inner rotor; 14. Second rotating shaft; 15. Permanent magnet; 16. Outer rotor; 17. Support gear; 18. Bracket; 19. Driven gear. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0042] It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings of this specification are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation conditions of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. In the description of this invention, it should be understood that the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are merely for the convenience of describing the invention and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of those features. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0043] It should also be noted that in the embodiments of this application, the same reference numerals are used to denote the same component or the same part.

[0044] A superconducting motor (HTS motor) is a type of motor whose windings are made of superconducting materials and can carry high-density currents in a strong magnetic field. Utilizing the characteristic that superconducting materials have zero resistance at low temperatures, a stronger current can pass through wires of the same specifications, generating a high-strength magnetic field. This results in a significantly smaller motor size, higher power density, and higher efficiency.

[0045] To date, research on superconducting motors has mainly focused on superconducting synchronous generators and superconducting monopole motors. Because the stator windings of the motors use superconducting tape, the AC losses are very large at power frequency. Therefore, superconducting synchronous generators usually use superconducting coils as rotor excitation windings, while the stator windings still use conventional copper windings.

[0046] Currently, there are three main types of superconducting materials that have achieved large-scale commercialization: low-temperature superconducting materials (superconducting critical temperature below 25K), first-generation high-temperature superconducting materials (Bi-based), and second-generation high-temperature superconducting materials (Y-based). Low-temperature superconducting materials are commercially mature, with relatively low tape prices, and are mainly used in low-field magnetic fields of 15T and below. High-temperature superconducting materials have high upper limits on critical magnetic fields and strong current-carrying capacity, allowing for smaller superconducting devices and offering greater potential for large-scale applications. Among these, the manufacturing of most first-generation high-temperature superconducting materials (BSCCO) tapes relies heavily on silver as a raw material, making cost reduction difficult and limiting commercial application. In contrast, the raw materials for the baseband and buffer protective layer of second-generation high-temperature superconducting materials (YBCO) tapes are mainly stainless steel and copper, allowing for significant cost reduction. With advancements in multilayer thin-film fabrication technology and the economies of scale brought about by large-scale manufacturing of kilometer-long tapes, the price of second-generation high-temperature superconducting tapes continues to decline, and product yields are improving, further accelerating the industrial application of high-temperature superconducting technology.

[0047] High-temperature superconducting magnets have advantages such as high magnetic field strength, strong operational stability, low risk of quenching, low cooling cost, and small size, making them highly promising for commercial applications and with a wider range of applications.

[0048] (1) High-temperature superconducting magnets have a high upper limit of critical magnetic field, currently the highest field strength can be 45T, which can be used in fields with high field magnetic field requirements such as NMR (nuclear magnetic resonance spectrometer) above 15T and compact controllable nuclear fusion.

[0049] (2) High-temperature superconducting magnets have strong operational stability and low risk of quenching. They can be processed without insulation, which greatly improves the robustness of superconducting magnets. The critical temperature of high-temperature superconducting materials is usually above 77K in the liquid helium temperature range. Compared with low-temperature superconducting materials, high-temperature superconducting materials have the characteristics of a wide transition temperature range, a relatively large operating temperature range, a slower quenching propagation speed, and a larger minimum quenching energy. From the perspective of heat resistance, the latent heat of vaporization of liquid helium is 2.6kJ / L, and that of liquid nitrogen is 160kJ / L. High-temperature superconductors can withstand much greater heat accumulation than low-temperature superconductors. At the same time, the alloy base material of high-temperature superconducting tapes can prevent magnetic flux movement, reduce the released heat, and lower the risk of quenching. High-temperature superconducting magnets are more stable, and the frictional heat generated by mechanical disturbances is insufficient to cause them to lose quench. Therefore, during winding, epoxy resin curing can be omitted, and non-insulating methods can also be used. In non-insulated high-temperature superconducting magnets, the baseband and protective layer of the tape act as "electrical insulation" materials between the turns of the superconducting layer. Once quench occurs, the resistance of the superconducting layer will rapidly rise to an order of magnitude comparable to that of these metal materials. Part of the current can be automatically shunted through the inter-turn contact to bypass the quench point, effectively suppressing the further development of quench. Compared with traditional insulated coils, this significantly improves the robustness of superconducting magnets and the overall engineering current density. Since non-insulated coils are self-stabilizing, active protection systems such as heaters are generally not required.

[0050] (3) The cooling cost of high-temperature superconducting magnets is relatively low. Compared with dry low-temperature superconducting magnets that require multiple two-stage refrigeration units, high-temperature superconducting magnets only require a single-stage refrigeration unit for magnet cooling, and the magnet system is relatively small in size.

[0051] However, to maintain the constant current mode of high-temperature superconducting magnets, an external power source is typically used to charge the magnets through copper current leads, which is a considerable heat source for the cooling system. Traditional current leads are connected between the cryogenic Dewar and room temperature; the huge temperature difference creates a heat leakage source at the current leads. Furthermore, Joule heating generated by joint resistance, magnetic flux creep, and AC losses during excitation operation creates additional heat sources, placing a heavy burden on the refrigeration equipment and affecting its safe and stable operation.

[0052] The purpose of this invention is to provide a wireless power supply system for offshore superconducting wind turbines, in order to solve the problems existing in the prior art, simplify the equipment composition, and reduce heat loss.

[0053] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0054] Please refer to Figure 1This embodiment provides a wireless power supply system for offshore superconducting wind turbines, including a housing 3 and a wireless power supply device for a vacuum Dewar 7, a superconducting motor, and a rotary magnetic flux pump disposed inside the housing 3. The vacuum Dewar 7 has a rotating cooling device 5 inside, powered by an offshore wind turbine. The superconducting motor includes an armature winding 6 fixed on the inner wall of the housing 3 and an excitation winding 8 evenly arranged around the outer periphery of the cooling device 5. The rotary flux pump wireless power supply device includes an inner rotor 13 and an outer rotor 16 arranged opposite to each other on the inner and outer sides of the vacuum Dewar 7, and the inner rotor 13 and the outer rotor 16 rotate coaxially with the excitation winding 8. The outer periphery of the inner rotor 13 is provided with a high-temperature superconducting stator strip 12 that is electrically connected to the excitation winding 8 in a one-to-one correspondence. The outer rotor 16 is provided with a permanent magnet 15 on the side facing the inner rotor 13 that corresponds to the high-temperature superconducting stator strip 12 in a one-to-one correspondence. The outer rotor 16 and the inner rotor 13 rotate at a differential speed. The permanent magnet 15 induces a DC output voltage on the high-temperature superconducting stator strip 12, inputs DC current to the excitation winding 8, forms a magnetic field, and induces an output voltage at the armature winding 6 of the superconducting motor.

[0055] Specifically, the vacuum Dewar 7 uses non-magnetic materials, with laminated silicon steel as the external magnetic shielding layer to protect electrical equipment. Internally, it houses a cooling device 5 that provides a cryogenic environment. One end of the cooling device 5 is fixedly connected to the first rotating shaft 2 of the offshore wind turbine, and it rotates coaxially with the offshore wind turbine under the drive of the first rotating shaft 2, which passes through the casing 3 and the vacuum Dewar 7. The cooling device 5 is made of stainless steel and uses liquid nitrogen introduced through a liquid nitrogen input pipe 1 that passes through the first rotating shaft 2 to provide cooling for the cryogenic vacuum environment inside the vacuum Dewar 7. This ensures that the high-temperature superconducting strip on the excitation winding 8 and the inner rotor 13 maintains a superconducting state and operates safely and reliably.

[0056] The vacuum Dewar 7 has internal support members 4 for supporting the cooling device 5, located at both ends of the cooling device 5. A bearing is installed on the outer periphery of the end of the cooling device 5 closest to the first rotating shaft 2, and is rotatably connected to the support member 4 at that end via the bearing. The inner rotor 13 of the rotary flux pump wireless power supply device is installed at the end of the cooling device 5 away from the first rotating shaft 2. The inner rotor 13 has a mounting part for mounting a bearing, and is rotatably connected to the other support member 4 located at this end of the cooling device 5 via the bearing.

[0057] To ensure the stability of the refrigeration device 5 rotating at high speed during operation, the number of support members 4 is not limited to two, but can also be multiple members evenly arranged along the axial direction of the refrigeration device 5. The refrigeration device 5 is rotatably connected to multiple support members 4 through multiple bearings that are set accordingly.

[0058] The excitation winding 8 of the superconducting motor is a non-insulated double-panel coil, made of second-generation high-temperature superconducting tape YBCO and stainless steel wound on an epoxy resin skeleton. Multiple sets of excitation coils are evenly arranged around the outer periphery of the cooling unit 5, and rotate coaxially with the offshore wind turbine under its drive. The structure of the excitation winding 8 of the superconducting motor is not limited to the double-panel coil form, and can also adopt any other structural form that can achieve the same function.

[0059] The inner rotor 13 of the rotary flux pump wireless power supply device has an alumina yoke, which does not alter the magnetic circuit of each high-temperature superconducting stator strip 12. The inner rotor 13 is fixedly installed at the other end of the cooling device 5 away from the first rotating shaft 2, located inside the vacuum Dewar 7 in a low-temperature cooling environment, and rotates coaxially with the offshore wind turbine under the drive of the cooling device 5. Multiple high-temperature superconducting stator strips 12 are evenly wound side-by-side on the annular yoke of the inner rotor 13, forming the inner rotor excitation coil. In this embodiment, it is specifically configured as 12 YBCO stator strips with a width of 10mm. Each high-temperature superconducting stator strip 12 is welded to the excitation winding 8 of the superconducting motor via a lead solder joint 9.

[0060] The high-temperature superconducting stator strip 12 is connected in series with the excitation winding 8. Multiple sets of high-temperature superconducting stator strips 12 and excitation windings 8 do not interfere with each other, forming a modular design. When a certain set of coils fails, the other superconducting coils can still operate reliably.

[0061] The outer rotor 16 of the rotary flux pump wireless power supply device is made of epoxy resin. Located outside the low-temperature vacuum Dewar 7 at room temperature, it is supported by a bracket 18 and a second rotating shaft 14 located outside the vacuum Dewar 7. Driven by the drive motor 11 and transmission gears, it rotates coaxially with the inner rotor 13. Permanent magnets 15, corresponding one-to-one with the high-temperature superconducting stator strip 12, are evenly distributed on the side near the inner rotor 13. In this embodiment, the permanent magnets 15 are 12 cylindrical permanent magnets 15 with a radius of 5mm, model N52, corresponding to the 12 YBCO stator strips evenly wound on the annular yoke of the inner rotor 13. They have better magnetic field distribution and stronger magnetic field strength, and are arranged with the same pole on the outer rotor 16 of the rotary flux pump wireless power supply device.

[0062] It should be noted that the diameter of the permanent magnet 15 is adjusted to half the width of the stator strip of the wireless power supply device, but it is not limited to half the width. The selection of the permanent magnet 15 is not limited to the N52 cylindrical permanent magnet; any other structural model that can achieve the same function can also be selected.

[0063] As a preferred embodiment of this invention, such as Figure 1 and Figure 2As shown, the inner rotor 13 and the outer rotor 16 are arranged opposite each other. The spacing between the high-temperature superconducting stator strips 12 uniformly wound on the annular magnetic yoke of the inner rotor 13 is consistent with the spacing between the permanent magnets 15 arranged on the outer rotor 16, and the radii of the multiple permanent magnets 15 from the center of the outer rotor 16 are the same.

[0064] In this design, the mounting portion for installing the bearing is located on the outer periphery of the annular magnetic yoke of the inner rotor 13. The high-temperature superconducting stator strip 12 is wound through the hole in the mounting portion. The inner rotor 13 is rotatably connected to the support member 4 via the bearing. The high-temperature superconducting stator strip 12, uniformly wound on the annular magnetic yoke of the inner rotor 13, is located on the outer side of the inner rotor 13 facing the outer rotor 16, opposite to one end face of the permanent magnet 15 mounted on the outer rotor 16. The magnetization direction of the permanent magnet 15 is coaxial, and the same pole faces the high-temperature superconducting stator strip 12 on the inner rotor 13. At this time, the portion of the vacuum Dewar 7 between the inner rotor 13 and the outer rotor 16 is a planar structure. The sides of the inner rotor 13 facing the outer rotor 16 and the sides of the outer rotor 16 facing the inner rotor 13 are located on the inner and outer sides of this planar structure, respectively.

[0065] As another preferred embodiment, such as Figure 3 As shown, the inner rotor 13 and the outer rotor 16 adopt an internal and external coupling form. The spacing between the high-temperature superconducting stator strips 12 uniformly wound on the annular magnetic yoke of the inner rotor 13 is consistent with the spacing between the permanent magnets 15 set on the outer rotor 16, and the radii of the multiple permanent magnets 15 from the center of the outer rotor 16 are the same.

[0066] In this design, the portion of the outer rotor 16 opposite to the inner rotor 13 adopts a ring structure. The inner rotor 13 is located within the inner ring of the outer rotor 16. Permanent magnets 15 are radially and uniformly arranged on the inner circumferential surface of the ring, with the magnetization direction of the permanent magnets 15 pointing towards the rotation axis. The portion of the high-temperature superconducting stator strip 12 uniformly wound on the annular magnetic yoke of the inner rotor 13 located on the outer circumferential surface of the inner rotor 13 is opposite to the end face of the permanent magnets 15 facing the inner rotor 13. A mounting part for mounting bearings is provided on the side of the inner rotor 13 away from the outer rotor 16, and it is rotatably connected to the support member 4 through the bearings. At this time, the portion of the vacuum Dewar 7 between the inner rotor 13 and the outer rotor 16 is an outwardly convex structure. This outwardly convex structure extends into the inner ring of the outer rotor 16. The outer circumferential surface of the inner rotor 13 opposite to the outer rotor 16 and the inner circumferential surface of the outer rotor 16 opposite to the inner rotor 13 are respectively located on the inner and outer sides of the radial direction of the outwardly convex structure.

[0067] It should be noted that the number of high-temperature superconducting stator strips 12 uniformly wound in parallel on the annular magnetic yoke of the inner rotor 13 and the number of permanent magnets 15 disposed on the outer rotor 16 are determined according to the number of excitation windings 8 of the superconducting motor, and are not limited to the 12 exemplified in this embodiment. Furthermore, the height and number of permanent magnets are selected based on a comprehensive consideration of factors such as the rotor magnetic field of the wireless power supply device and the gap width between the rotor and the stator.

[0068] The portion of the vacuum Dewar 7 located between the inner rotor 13 and the outer rotor 16 is made of G10 composite material. G10 material possesses excellent insulation properties at the same thickness as traditional insulating materials. Therefore, while maintaining the same electrical performance, its thickness can be reduced, thus decreasing the air gap space occupied between the inner rotor 13 and the outer rotor 16, allowing for air gap compression. Consequently, using G10 composite material effectively reduces the gap between the permanent magnet 15 and the high-temperature superconducting stator strip 12, increases the magnetic field strength on the high-temperature superconducting stator strip 12, and improves the excitation current in the inner rotor excitation coil.

[0069] G10 composite material is a composite material composed of glass fiber and epoxy resin. It is widely used in aerospace, electronics, automotive, medical device and other fields. It has excellent mechanical properties, electrical insulation properties and chemical corrosion resistance, and is an ideal engineering material.

[0070] First, G10 composites possess excellent mechanical properties. Due to their fiber-reinforced resin matrix structure, G10 composites exhibit high strength and rigidity, enabling them to withstand high-intensity stress environments. Compared to metallic materials, G10 composites are lighter, making them more flexible and convenient in engineering design.

[0071] Secondly, G10 composite materials possess excellent electrical insulation properties. Composed of epoxy resin with superior insulating properties, G10 composite materials exhibit excellent insulation performance, effectively isolating current and voltage, and reducing electrical equipment malfunctions and accidents. Therefore, G10 composite materials are widely used in the electronics field for insulating materials, circuit boards, and electrical insulation components.

[0072] Furthermore, G10 composite materials also exhibit excellent chemical corrosion resistance. Due to the corrosion resistance of glass fiber and the chemical stability of epoxy resin, G10 composite materials can maintain stable performance in harsh environments such as acids, alkalis, and solvents. This makes them widely used in chemical, marine, and medical device industries.

[0073] Furthermore, G10 composite materials also possess excellent processing properties. They can be manufactured into parts of various shapes and sizes through processes such as molding, extrusion, and pressing, thus adapting to diverse engineering needs. Due to the unique composition of its material, G10 composite materials also exhibit good dimensional stability, are not easily deformed or expanded, and can ensure the precision and stability of products.

[0074] In summary, the high strength and rigidity of the G10 composite material ensure the overall strength requirements of the refrigeration device 5 under the high-speed rotation of the offshore wind turbine shaft; its resistance to deformation and expansion ensures the overall stability of the refrigeration device 5 in the cryogenic environment generated by liquid nitrogen; and its insulation performance, which is far superior to that of conventional insulating materials, allows for a reduction in thickness while maintaining the same electrical performance, thereby reducing the magnetic flux gap between the inner rotor 13 and the outer rotor 16, enhancing the magnetic field strength on the high-temperature superconducting stator strip 12, and increasing the excitation current of the superconducting motor excitation winding 8, thus significantly improving the charging efficiency of the superconducting motor excitation winding 8.

[0075] In this embodiment, considering economic factors, only the portion of the vacuum Dewar 7 located between the inner rotor 13 and the outer rotor 16 is made of G10 composite material, while the other parts are made of stainless steel. It should be noted that the proportion of G10 composite material can be reasonably allocated as needed, not limited to the portion between the inner rotor 13 and the outer rotor 16, such as the end face of the vacuum Dewar 7 near the inner rotor 13 and the outer rotor 16, the axial sidewalls of the vacuum Dewar 7, or all the sidewalls of the vacuum Dewar 7. It should also be noted that the material selection for the portion of the vacuum Dewar 7 located between the inner rotor 13 and the outer rotor 16 is not limited to G10; any other material that can achieve the same function can be used.

[0076] The working principle of this embodiment is as follows:

[0077] This embodiment introduces superconducting flux pump technology, which injects magnetic flux into a closed coil through non-electrical connection to compensate for the current attenuation of the high-temperature superconducting magnet. It eliminates the need for current leads, thus eliminating the heat source of the current leads themselves, and continuously provides DC power to the excitation winding 8. It eliminates the traditional slip ring structure in the motor, eliminates the mechanical friction heat loss of the equipment, and blocks the heat conduction between room temperature and low temperature environment, which can effectively reduce the cooling demand. At the same time, the modular design eliminates the slip ring structure, optimizes mechanical wear, and reduces the complexity of equipment maintenance.

[0078] The rotary flux pump wireless power supply device directly provides DC power to the excitation winding 8, eliminating the need for a frequency converter to convert the power frequency to radio frequency power, and then rectifying the alternating current through a rectifier-inverter unit. This simplifies the equipment composition, resulting in a simple structure and high maintainability, as it eliminates the need for complex electromagnetic devices and control units. Furthermore, the superconducting flux pump does not generate a large amount of Joule heat during operation, unlike conversion circuits, which is beneficial for long-term reliable operation.

[0079] In this embodiment, the inner rotor 13 of the rotary flux pump wireless power supply device, with high-temperature superconducting stator strip 12 wound around it, is placed inside a low-temperature vacuum Dewar 7. The vacuum Dewar 7 is kept at a low temperature by a cooling device 5 to maintain the superconducting state of the high-temperature superconducting stator strip 12. At the same time, the outer rotor 16 of the rotary flux pump wireless power supply device is moved out of the low-temperature environment and placed in a room-temperature environment outside the vacuum Dewar 7. The outer rotor 16 is supported by a bracket 18 and a second rotating shaft 14 located outside the vacuum Dewar 7, so that the inner rotor 13 and the outer rotor 16 form a non-direct contact method. This eliminates the heat conduction caused by the rotating shaft of a traditional flux pump in a low-temperature environment, solves the mechanical friction between the mechanical transmission shaft and the low-temperature vacuum Dewar 7, improves the dynamic sealing performance in the low-temperature environment, and further simplifies the structure of the offshore superconducting wind turbine.

[0080] Furthermore, considering the randomness, intermittency, and volatility of offshore wind energy, wind speed variations directly lead to instability in wind turbine rotation speed, which in turn alters the output power of the high-temperature superconducting flux pump wireless power supply device. This causes fluctuations in the excitation input current of the superconducting wind turbine, affecting the output power quality of the superconducting wind turbine. The impact of wind farm power fluctuations on the power system is manifested in the following aspects:

[0081] 1. Impact on voltage stability: Power fluctuations in wind farms affect the stability of grid voltage. Large power fluctuations can affect grid voltage and even lead to grid voltage instability, causing various power accidents.

[0082] 2. Impact on frequency stability: Wind farm power fluctuations have a direct impact on grid frequency stability, especially in small grid systems where the impact is greater.

[0083] 3. Impact on power grid security: Power fluctuations in wind farms lead to an increase in the number of trips of circuit breakers and protection devices, which increases the electrical stress and mechanical stress on the equipment, thereby affecting the security of the power system.

[0084] Due to the uncertainty and uncontrollability of wind power, the power supply from grid-connected wind turbines cannot meet the requirements of stability, continuity, and adjustability, and the constant changes in output power can easily impact the power grid. Because of the unpredictability of wind power, dispatching and operation personnel cannot make effective power generation plans, leading to a series of consequences such as increased system backup power, peak-shaving capacity, and system operating costs, as well as threats to the safe and stable operation of the system.

[0085] To address the issue of input current fluctuation in the excitation winding of a superconducting wind turbine, this embodiment introduces a feedback transmission device into the wireless power supply equipment for the rotary flux pump. By monitoring the rotational speed of the offshore wind turbine, the rotational speed of the outer rotor 16 is adjusted, ensuring a stable speed difference between the outer rotor 16 and the inner rotor 13. This stabilizes the excitation current of the superconducting motor excitation winding 8, thereby enabling the offshore superconducting wind turbine to operate safely, stably, and reliably.

[0086] Specifically, the negative feedback transmission device includes a monitoring system, a drive motor 11, and a gear transmission system. The drive motor 11 can be a servo motor or any other motor capable of performing the same function. The drive motor 11 is electrically connected to the monitoring system. The gear transmission system includes a driving gear 10 fixedly mounted at the output end of the drive motor 11, a driven gear fixedly mounted on the outer periphery of the outer rotor 16, and a support gear 17 opposite the driving gear 10 to ensure the rotational stability of the outer rotor 16. The drive motor 11 is fixedly mounted outside the housing 3, and its output shaft passes through the housing 3 and is fixedly connected to the driving gear 10 located inside the housing 3. The driven gear is based on the outer rotor 16 of the rotary flux pump wireless power supply device, with carbon steel gears inlaid on the outer periphery of the outer rotor 16, meshing with the driving gear 10. The support gear 17 is rotatably mounted on the inner wall of the housing 3 on the side opposite to the driving gear 10, thereby providing effective and stable support for the rotating outer rotor 16.

[0087] The monitoring system adopts traditional PID control. It collects the rotational speed of the first rotating shaft 2 in real time, compares it with the rated value, calculates the error, and calculates the control quantity based on the error. It predicts future error changes and adjusts the torque of the drive motor 11 in advance to adjust the rotational speed of the outer rotor 16, maintains the speed difference between the outer rotor 16 and the inner rotor 13 of the rotary flux pump wireless power supply equipment, and maintains the current of the superconducting motor excitation winding 8 constant.

[0088] This invention introduces superconducting flux pump technology, which uses non-contact rotary excitation to inject magnetic flux into a closed coil through non-electrical connection to compensate for the current attenuation of the high-temperature superconducting magnet. It eliminates the need for traditional current leads, thus eliminating the heat leakage source formed by the current lead bridging between room temperature and low temperature environments, as well as the Joule heat generated during the excitation operation itself. This reduces the cooling demand and improves the energy utilization efficiency of the equipment. At the same time, the modular design eliminates the slip ring structure, optimizes mechanical wear, and reduces the complexity of equipment maintenance.

[0089] Non-contact rotary excitation induces DC output in the high-temperature superconducting stator strip 12, eliminating the need for a separate rectifier. This simplifies the structure of the superconducting fan equipment, eliminates additional energy consumption, and effectively improves energy utilization.

[0090] The electrical parameters output by the rotary flux pump wireless power supply equipment are DC output, eliminating the slip rings and brushes in traditional fans, simplifying the rotor structure of superconducting fans, eliminating the mechanical losses of slip rings and brushes, and making it easier to inspect and maintain.

[0091] In the inner rotor 13 structure of the rotary flux pump wireless power supply device, each high-temperature superconducting stator strip 12 is individually connected to the excitation winding 8 of the superconducting motor, forming a modular design. When one coil fails, the other superconducting coils can still operate reliably.

[0092] The rotary flux pump wireless power supply device transfers the rotary excitation outer rotor 16 from the low-temperature Dewar and places it in a room temperature environment, effectively avoiding frictional heat and conduction heat of the mechanical transmission shaft, reducing the cooling demand of the refrigerator, and reducing cooling costs and operation and maintenance costs.

[0093] The rotary flux pump wireless power supply device uses G10 composite material for the Dewar between the inner rotor 13 and the outer rotor 16. G10 material, with the same thickness as traditional insulating materials, possesses excellent insulation performance and high-temperature resistance. Therefore, while maintaining the same electrical performance, its thickness can be reduced, thus decreasing the air gap space occupied between the inner rotor 13 and the outer rotor 16, allowing for air gap compression. Using G10 composite material effectively reduces the gap between the permanent magnet 15 and the high-temperature superconducting stator strip 12, increases the magnetic field strength on the high-temperature superconducting stator strip 12, and improves the excitation current in the high-temperature superconducting double-pancake coil.

[0094] Offshore wind energy is intermittent and fluctuates, causing the rotational speed of the superconducting wind turbine to change continuously. By setting up a negative feedback transmission device to monitor the rotational speed of the offshore wind turbine, the rotational speed of the outer rotor 16 is adjusted to maintain the speed difference between the permanent magnet 15 and the high-temperature superconducting stator strip 12, so that the traveling wave magnetic field on the high-temperature superconducting stator strip 12 remains stable, thereby ensuring that the excitation current input of the superconducting wind turbine is constant.

[0095] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0096] If this invention discloses or relates to components or structural parts that are fixedly connected to each other, then, unless otherwise stated, a fixed connection can be understood as: a fixed connection that can be detached (e.g., using bolts or screws), or a fixed connection that cannot be detached (e.g., riveting, welding). Of course, a fixed connection can also be replaced by an integral structure (e.g., manufactured in one piece using a casting process) (except where it is obviously impossible to use an integral molding process).

[0097] In addition, unless otherwise stated, the terms used in any of the technical solutions disclosed in this invention to indicate positional relationships or shapes include states or shapes that are similar to, close to, or approximate with those states or shapes.

[0098] Any component provided by this invention can be assembled from multiple individual components or can be a single component manufactured by a one-piece molding process.

[0099] Any adaptive changes made according to actual needs are within the scope of protection of this invention.

[0100] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0101] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A wireless power supply system for offshore superconducting wind turbines, characterized in that: Includes a housing and a wireless power supply device for a vacuum Dewar, a superconducting motor, and a rotary flux pump disposed inside the housing; The vacuum Dewar is equipped with a refrigeration device that rotates inside, and the power source for the rotation of the refrigeration device is an offshore wind turbine. The superconducting motor includes an armature winding fixedly disposed on the inner wall of the housing and an excitation winding uniformly arranged on the outer periphery of the refrigeration device. The rotary flux pump wireless power supply device includes an inner rotor and an outer rotor arranged opposite to each other. The inner rotor is disposed inside the vacuum Dewar, and the outer rotor is disposed outside the vacuum Dewar. The inner rotor and the outer rotor rotate coaxially with the excitation winding. The outer periphery of the inner rotor is provided with high-temperature superconducting stator strips that are electrically connected to the excitation windings one by one; the high-temperature superconducting stator strips on the inner rotor are wound independently in parallel; the outer rotor is provided with permanent magnets that correspond one by one to the high-temperature superconducting stator strips on the side facing the inner rotor. The outer rotor and the inner rotor rotate at a different speed. The permanent magnet induces a DC output voltage on the high-temperature superconducting stator tape, inputs DC current to the excitation winding, forms a magnetic field, and induces an output voltage at the armature winding of the superconducting motor. It also includes a negative feedback transmission device that monitors the rotational speed of the first rotating shaft of the fan and adjusts the rotational speed of the outer rotor accordingly; The negative feedback transmission device includes a monitoring system, a drive motor electrically connected to the monitoring system, a driving gear fixedly disposed at the output end of the drive motor, and a driven gear fixedly connected to the outer rotor; The monitoring system adopts traditional PID control. It collects the rotational speed of the first rotating shaft in real time, compares it with the rated value, calculates the error, and calculates the control quantity based on the error. It predicts future error changes and adjusts the torque of the drive motor in advance to adjust the speed of the outer rotor, maintain the speed difference between the outer rotor and the inner rotor of the rotary flux pump wireless power supply equipment, and maintain the constant current of the superconducting motor excitation winding.

2. The wireless power supply system for offshore superconducting wind turbines according to claim 1, characterized in that: The excitation winding is a non-insulated double-pane coil, which is made of second-generation high-temperature superconducting tape YBCO and stainless steel wound on an epoxy resin skeleton.

3. The wireless power supply system for offshore superconducting wind turbines according to claim 1, characterized in that: The high-temperature superconducting stator strip is welded to the excitation winding via a lead solder joint.

4. The wireless power supply system for offshore superconducting wind turbines according to claim 1, characterized in that: The annular magnetic yoke of the inner rotor is made of aluminum oxide.

5. The wireless power supply system for offshore superconducting wind turbines according to claim 1, characterized in that: The portion of the vacuum Dewar located between the inner and outer rotors is made of G10 composite material.

6. The wireless power supply system for offshore superconducting wind turbines according to claim 1, characterized in that: The refrigeration device is fixedly connected to the offshore wind turbine via a first rotating shaft that passes through the vacuum Dewar and the housing.

7. The wireless power supply system for offshore superconducting wind turbines according to claim 1, characterized in that: The vacuum Dewar has a support for mounting the refrigeration device inside, and the refrigeration device is rotatably connected to the support via a bearing.

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