A Coupled Repair System for Asymmetric Faults in Dual-Rotor Wind Turbines

Abstract

This invention discloses a coupling repair system for asymmetrical faults in a dual-rotor wind turbine, comprising a nacelle, an a-rotor, and a b-rotor. The a-rotor and b-rotor rotate symmetrically at the front and rear ends of the nacelle, coaxially. The nacelle includes an a-gearbox, a b-gearbox, an a-generator, a b-generator, and an asymmetrical fault coupling system. The a-rotor shaft of the a-rotor is connected to the input end of the a-gearbox, and the output end of the a-gearbox is connected to the a-shaft. The a-permanent magnet rotor of the a-generator rotates synchronously with the a-shaft. The b-rotor shaft of the b-rotor is connected to the input end of the b-gearbox, and the output end of the b-gearbox is connected to the b-shaft. The b-permanent magnet rotor of the b-generator rotates synchronously with the b-shaft. The a-rotor and b-rotor are counter-rotating rotors, rotating in opposite directions under wind power. This invention provides a reliable repair solution for asymmetrical faults in dual-rotor wind turbines.

Description

Technical Field

[0001] This invention belongs to the field of wind turbines. Background Technology

[0002] To overcome the bottleneck of wind energy utilization efficiency in traditional single-rotor wind turbines, dual-rotor wind turbines, which adopt a coaxial counter-rotating rotor structure (i.e., the front rotor and the rear rotor rotate in opposite directions), can effectively reduce wake energy loss and improve the wind energy utilization coefficient to 0.4-0.5, which is significantly better than single-rotor models. This has become an important development direction for medium and large-scale wind farms.

[0003] The core transmission and power generation system of existing dual-rotor wind turbines usually adopts an independent configuration of "dual rotors, dual gearboxes, and dual generators": the front rotor drives the front permanent magnet synchronous generator through a planetary gear gearbox, and the rear rotor drives the rear permanent magnet synchronous generator through another set of gearboxes of the same type. The two generators realize power output through independent MPPT control systems. During normal operation, wind energy can be fully utilized and grid connection requirements can be met. However, during long-term outdoor operation, dual-rotor wind turbines are frequently affected by factors such as extreme weather, mechanical wear, and electrical aging, leading to asymmetrical faults (i.e., a single generator experiencing an open circuit fault, such as an open stator coil or a broken output cable). When one of the generators is open-circuited, its stator coil cannot generate back electromotive force, causing the load on the corresponding permanent magnet rotor to suddenly drop to zero. At this time, the wind turbine on that side will accelerate rapidly due to the loss of load constraint, with the speed increase rate reaching 50 r / min / s, which can easily exceed 120% of the rated speed, causing serious safety hazards such as wind turbine blade flutter and shaft fatigue damage. To address the aforementioned faults, existing technologies primarily employ a direct braking and locking solution: a disc-type electromagnetic brake or mechanical brake mounted on the shaft is used to directly lock the permanent magnet rotor and impeller on the faulty side, forcibly stopping their rotation to prevent overspeeding. However, this solution has the following three major drawbacks: 1. High risk of mechanical stress: When the brake is locked, the static torque between the faulty side shaft and the wind turbine can reach 3-5 times the normal operating torque, and the stress exceeds 80% of the material yield strength. Long-term and frequent use can easily lead to irreversible damage such as shaft deformation and wind turbine hub cracking. 2. Serious energy waste: After being locked, the faulty side wind turbine completely loses its power generation capacity. Since dual-rotor wind turbines are mostly installed in remote areas, such as plateaus and offshore, maintenance by staff requires a long period of time. During this period, the wind energy resources on the faulty side are completely wasted, resulting in significant economic losses. 3. No kinetic energy co-utilization mechanism: The existing scheme cannot transfer the rotational kinetic energy of the faulty wind turbine to the normal generator. The normal side can only utilize wind energy from one side, which further reduces the overall power generation efficiency. In addition, some improvement solutions attempt to use rigid mechanical coupling (such as gear clutch) to connect the dual rotors. However, due to the extremely high requirements for the rotational synchronization of the dual rotors (the coaxiality error must be ≤0.02mm), rigid coupling is prone to generating impact loads, leading to new problems such as clutch tooth surface wear and abnormal noise from the transmission. Furthermore, it still cannot solve the requirements for kinetic energy recovery and flexible buffering on the fault side. In summary, existing dual-rotor wind turbines struggle to simultaneously achieve the coordinated goals of overspeed suppression, kinetic energy recovery, and mechanical protection when dealing with asymmetric faults. A novel coupled repair system is urgently needed to address the shortcomings of existing technologies and improve the operational reliability and energy efficiency of dual-rotor wind turbines. Summary of the Invention

[0004] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a coupling repair system for asymmetrical faults in dual-rotor wind turbines, providing a reliable repair solution for asymmetrical faults in dual-rotor wind turbines.

[0005] Technical Solution: To achieve the above objectives, the present invention provides a coupling repair system for asymmetrical faults in a dual-rotor wind turbine, comprising a nacelle, an a-rotor, and a b-rotor, the a-rotor and b-rotor rotating symmetrically at the front and rear ends of the nacelle coaxially; the nacelle includes an a-gearbox, a b-gearbox, an a-generator, a b-generator, and an asymmetrical fault coupling system; the a-rotor shaft of the a-rotor is connected to the input end of the a-gearbox, the output end of the a-gearbox is connected to the a-rotor shaft, and the a-permanent magnet rotor of the a-generator rotates synchronously with the a-rotor shaft; the b-rotor shaft of the b-rotor is connected to the input end of the b-gearbox, and the output end of the b-gearbox is connected to the b-rotor shaft. The permanent magnet rotor of generator b rotates synchronously with the shaft b. Wind turbines a and b are counter-rotating wind turbines, rotating in opposite directions under wind power. Under the transmission of gearboxes a and b, the shafts of generators a and b rotate in the same direction, thus making the permanent magnet rotors of generators a and b rotate in the same direction. The asymmetric fault coupling system does not intervene under normal conditions. When one of generators a and b experiences an open circuit fault, the asymmetric fault coupling system intervenes, causing the permanent magnet rotors of generators a and b to be magnetically coupled under the intervention of the asymmetric fault coupling system.

[0006] Furthermore, both the a stator coil assembly of generator a and the b stator coil assembly of generator b are cylindrical bodies that run through the axis, with the induction coils distributed on the inner wall of the cylinder.

[0007] Furthermore, one end of permanent magnet rotor a is coaxially fixedly connected to shaft a; the end of permanent magnet rotor b, away from permanent magnet rotor a, is coaxially fixedly connected to shaft c. Shaft b and shaft c can both undergo relative displacement along the axial direction and maintain synchronous rotational motion.

[0008] Furthermore, the asymmetric fault coupling system includes a guide rail and a floating translation seat, the floating translation seat being guided and fitted to the guide rail by a slider; it also includes a hydraulic telescoping device that can drive the floating translation seat to slide along the guide rail; the c-shaft is rotatably mounted on the c-bearing housing through a bearing, and the c-bearing housing is fixedly connected to drive the floating translation seat.

[0009] It also includes a clutch support between stator coil assembly A and stator coil assembly B, with a floating translation seat fixedly connected to the upper end of the clutch support; an internal threaded rotating sleeve is rotatably mounted on the clutch support via an active clutch, the internal threaded rotating sleeve being coaxial with stator coil assembly A and stator coil assembly B; the active clutch has two states: locked and disengaged. When the active clutch is locked, the internal threaded rotating sleeve cannot rotate; when disengaged, the internal threaded rotating sleeve can rotate around its own axis; a threaded screw is coaxially threaded on the inner side of the internal threaded rotating sleeve, with a turntable A and a turntable B fixedly connected to both ends of the threaded screw, respectively, and a coupling ring A and a coupling ring B integrally connected to the ends of the turntable A and turntable B, respectively, coaxially. The inner rings of the coupling ring A and the coupling ring B are respectively arranged in a circumferential array with several permanent magnets A and several permanent magnets B.

[0010] The length of the permanent magnet rotor axis is greater than the length of the stator coil assembly axis, so that a small section of the permanent magnet rotor near the turntable (right end) is exposed outside the stator coil assembly. In the initial state, the small section of the permanent magnet rotor exposed outside the right end of the stator coil assembly is deviated from the enclosure of the coupling ring.

[0011] Furthermore, it also includes a friction head support fixed on the stator support, with a friction head of high friction coefficient fixed at the end of the friction head support. In the initial state, the friction head presses against the surface of turntable a, thereby suppressing the spontaneous rotation of turntable a.

[0012] Furthermore, under normal operating conditions, the permanent magnet rotor a is exposed outside the stator coil assembly a, within a small section of the area enclosed by the coupling ring a; and the permanent magnet rotor b is completely within the area enclosed by the stator coil assembly b; the rotation of the wind turbine a and the wind turbine b drives their respective generators a and b via the gearbox a and gearbox b, respectively. The generators a and b are in a decoupled state, while the friction head inhibits the spontaneous rotation of the integrated structure consisting of the turntable a, the screw thread, and the turntable b, and the active clutch is locked; the generators a and b operate stably under the control of their respective MPPT control systems and transmit electrical energy to the outside.

[0013] Furthermore, when generator A experiences a circuit breaker fault alone, the active clutch is first locked. The hydraulic telescoping device drives the floating translation seat to slide to the left along the guide rail. This causes the floating translation seat, clutch support, active clutch, internal thread rotating sleeve, threaded screw, A turntable, B turntable, A coupling ring, B coupling ring, C bearing housing, C shaft, and B permanent magnet rotor to translate to the left as a whole. The friction head automatically disengages from the A turntable. Finally, a small section of the left end of the B permanent magnet rotor moves to the left until it is exposed outside the left end of the B stator coil assembly. The A coupling ring moves to the left until it surrounds the originally exposed right end of the A permanent magnet rotor. At this time, the outer ring of permanent magnets on the right end of the A permanent magnet rotor and the inner ring of A permanent magnets on the A coupling ring enter a magnetic coupling state. The rotation, driven by magnetic coupling, causes coupling ring a to rotate, which in turn causes coupling ring a, turntable a, threaded screw, turntable b, and coupling ring b to rotate as a whole along the axis. Under the threaded transmission of the inner wall of the locked internal threaded rotating sleeve, the threaded screw is offset to the right relative to the internal threaded rotating sleeve, causing coupling ring a, turntable a, threaded screw, turntable b, and coupling ring b to offset to the right relative to the internal threaded rotating sleeve as a whole until the left end of the internal threaded rotating sleeve contacts turntable a, thus preventing the threaded screw and the internal threaded rotating sleeve from continuing threaded transmission. At this time, coupling ring b has been relatively displaced to the right to enclose the left end of permanent magnet rotor b. At this time, the outer ring of permanent magnets on the left end of permanent magnet rotor b and the inner ring of permanent magnets b on coupling ring b also enter a magnetic coupling state.

[0014] Simultaneously, the hydraulic expansion joint drives the floating translation seat to slide adaptively to the left along the guide rail, ensuring that the outer ring of permanent magnets on the right end of permanent magnet rotor a and the inner ring of permanent magnets a in a magnetic coupling state are always in a magnetic coupling state. Finally, the active clutch is controlled to enter the disengaged state from the locked state, so that the internal thread rotating sleeve, threaded screw, a turntable, b turntable, a coupling ring, and b coupling ring form a whole that can rotate freely along the axis. At this time, the whole formed by the internal thread rotating sleeve, threaded screw, a turntable, b turntable, a coupling ring, and b coupling ring acts as an intermediate medium to achieve non-rigid magnetic coupling between permanent magnet rotor a and permanent magnet rotor b.

[0015] Furthermore, if wind turbine A is still overspeeding, or if generator B is overloaded due to coupling, the existing braking system in the nacelle can be selectively activated to apply brakes and decelerate.

[0016] Beneficial effects: This invention solves the following core problems faced by traditional dual-rotor wind turbines in the event of asymmetrical failures: Effectively prevents overspeed damage to faulty wind turbines: Traditional solutions involve direct braking, which leads to structural stress concentration and energy waste. This solution uses magnetic coupling to transfer excess energy from the faulty wind turbine, suppressing its rotational speed under normal generator load. This eliminates the risk of overspeed damage due to sudden load drops and improves system safety.

[0017] Maximizing energy utilization and reducing energy waste: Unlike traditional braking shutdown solutions, this solution recovers and utilizes wind energy from the faulty side, transferring it to the normal power generation units for power generation. While waiting for maintenance, the system can still maintain partial power generation capacity, improving the overall energy efficiency and economic benefits of the equipment.

[0018] Achieving non-contact power transmission and reducing mechanical damage: Power is transmitted through magnetic coupling, a non-contact, flexible connection. This avoids the rigid impact, wear, and fatigue damage associated with traditional mechanical clutches or brakes, improving system reliability and lifespan.

[0019] This solution, through the innovative principle of "non-rigid magnetic coupling and multi-component collaborative control," breaks through the contradiction of existing technologies that "either sacrifice equipment to ensure safety or waste energy to ensure equipment safety," and achieves the triple collaborative goal of "overspeed suppression, kinetic energy recovery, and mechanical protection," providing a reliable repair solution for asymmetric faults in dual-rotor wind turbines. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of a dual-rotor wind turbine; Figure 2 This is a schematic diagram of the three states when an asymmetric fault-coupled system is intervened; Figure 3 for Figure 2 Cross-sectional views in three states; Figure 4 This is a schematic diagram of the internal rotating part of the device. Detailed Implementation

[0021] The invention will now be further described with reference to the accompanying drawings.

[0022] As shown in Figures 1 to 4, a coupling repair system for asymmetric faults in a dual-rotor wind turbine includes a nacelle 6, a rotor 1 (a) and a rotor 2 (b). Both rotor 1 (a) and rotor 2 (b) have 3-5 blades. The chord length of the blades gradually decreases radially from the blade root to the blade tip. The blades are made of glass fiber reinforced resin matrix composite material, which combines lightweight and high strength characteristics. The rotor 1 (a) and rotor 2 (b) rotate symmetrically at the front and rear ends of the nacelle 6 on the same axis. The nacelle 6 includes a transmission 4, a transmission 5, a generator 41, a generator 42, and an asymmetric fault coupling system. Transmissions 4 and 5 are both planetary gear transmissions with a transmission ratio range of 1:50-1:100, which can increase the low speed of the wind turbine (10-30 r / min) to the high speed required by the generator (1500-3000 r / min). Generators 41 and 42 are both permanent magnet synchronous generators with a rated power of 1.5MW-5MW and a rated voltage of 690V. The a wind turbine shaft 3 of the a wind turbine 1 is connected to the input end of the a transmission 4. The a wind turbine shaft 3 and the input end of the a transmission 4 are connected by a spline. The output end of the a transmission 4 is connected to the a rotating shaft 7. The a permanent magnet rotor 12 of the a generator 41 rotates synchronously with the a rotating shaft 7. The b-wind rotor 2's b-wind rotor shaft 11 is connected to the input end of the b-transmission 5, and the output end of the b-transmission 5 is connected to the b-rotor shaft 9. The b-permanent magnet rotor 13 of the b-generator 42 rotates synchronously with the b-rotor shaft 9. The structure and material of the b-permanent magnet rotor 13 are the same as those of the a-permanent magnet rotor 12 to ensure symmetrical performance of the two generators. The a-permanent magnet rotor 12 and the b-permanent magnet rotor 13 are coaxial, and their coaxiality error is ≤0.02mm to avoid electromagnetic noise caused by radial runout during rotation. To achieve better aerodynamic efficiency, wind turbine 1 (a) and wind turbine 2 (b) are counter-rotating wind turbines, rotating in opposite directions under wind power. However, this solution utilizes the internal transmission structure of gearbox 4 (a) or gearbox 5 (b). Specifically, gearbox 4 (a) adopts a forward transmission structure of "sun gear-planet gear-internal gear ring", while gearbox 5 (b) adds a reversing gear to the same basic structure, making the rotation directions of shaft 7 (a) and shaft 9 (b) the same, thereby making the rotation directions of permanent magnet rotor 12 (a) and permanent magnet rotor 13 (b) the same. The asymmetric fault coupling system does not intervene under normal conditions. At this time, the system power consumption is ≤50W, and only the standby pressure (5MPa) of the hydraulic expansion joint (23) is maintained. When one of the generators a41 and b42 experiences a circuit failure, the asymmetric fault coupling system intervenes, so that the permanent magnet rotor a12 and the permanent magnet rotor b13 are magnetically coupled under the intervention of the asymmetric fault coupling system, with a coupling torque range of 500-2000N·m. The stator coil assembly 20 of generator a41 and the stator coil assembly 21 of generator b42 are both fixed on stator support 10, which is fixed inside the engine compartment 6. A bearing housing 29 and a bearing housing 36 are respectively provided at both ends of the stator support 10, and deep groove ball bearings are installed in the bearing housings. A rotating shaft 7 and a rotating shaft 9 are rotatably mounted on bearing housing 29 and bearing housing 36 respectively through bearings. Both stator coil assembly 20 (a) and stator coil assembly 21 (b) are cylindrical bodies that run through the axis, with the induction coils distributed on the inner wall of the cylinder. One end of the permanent magnet rotor 12 (a) is coaxially fixedly connected to the rotating shaft 7 (a), with an interference fit and double positioning via a shoulder and a locking nut. The end of the permanent magnet rotor 13 (b) away from the permanent magnet rotor 12 is coaxially fixedly connected to the rotating shaft 27 (c), with the connection method identical to that of the permanent magnet rotor 12 and the rotating shaft 7 (a). The rotating shaft 9 (b) has a hexagonal section 28 near the rotating shaft 27 (c), and the rotating shaft 27 (c) has a corresponding hexagonal hole section. The hexagonal section 28 of the rotating shaft 9 and the hexagonal hole section of the rotating shaft 27 (c) are fitted with a fit accuracy of H7 / f6 and a clearance of 0.015-0.04mm, allowing the rotating shaft 9 (b) and the rotating shaft 27 (c) to both undergo relative displacement along the axial direction and maintain synchronous rotation. The asymmetric fault coupling system includes a guide rail 8 fixed to the top of the engine compartment 6. The guide rail 8 is a high-precision linear ball guide rail, and the length direction of the guide rail 8 is parallel to the axis direction of generator a 41 and generator b 42. It also includes a floating translation seat 26, which is guided and engaged with the guide rail 8 by a slider 24. It also includes a hydraulic expansion joint 23 that can drive the floating translation seat 26 to slide along the guide rail 8. The hydraulic expansion joint 23 is fixed on the stator coil assembly 20. The c-shaft 27 is rotatably mounted on the c-bearing seat 35 via a bearing. The bearing model installed in the c-bearing seat 35 is the same as that of the a-bearing seat 29. The c-bearing seat 35 is fixedly connected to the drive floating translation seat 26. The asymmetric fault coupling system also includes a clutch support 33 between stator coil assembly 20 (a) and stator coil assembly 21 (b). A floating translation seat 26 is fixedly connected to the upper end of the clutch support 33. An internal threaded rotating sleeve 15 is rotatably mounted on the clutch support 33 via an active clutch 14. The internal threaded rotating sleeve 15 is coaxial with stator coil assembly 20 (a) and stator coil assembly 21 (b). The active clutch 14 has two states: locked and disengaged. The active clutch 14 is an electromagnetic jaw clutch. When locked, the torque transmission capacity is ≥500 N·m. When disengaged, the separation gap is ≤0.5 mm. When the active clutch 14 is locked, the internal threaded rotating sleeve 15 cannot rotate. When disengaged, the internal threaded rotating sleeve 15 can rotate around its own axis. The inner side of the internal threaded rotating sleeve 15 is coaxially threaded with a threaded screw 25. The two ends of the threaded screw 25 are coaxially fixedly connected to a turntable 16 and a turntable 17, respectively, by key connection and locking nut fixation. The ends of the turntables 16 and 17 that are far apart from each other are coaxially integrally connected to a coupling ring 31 and a coupling ring 34, respectively. The inner diameter of the coupling rings 31 and 34 is 5-10mm larger than the outer diameter of the corresponding permanent magnet rotor to ensure no mechanical collision during coupling. The inner rings of the coupling rings 31 and 34 are respectively arranged in a circumferential array with a number of permanent magnets 18 and a number of permanent magnets 19. The material and magnetic density of the permanent magnets 18 and 19 are the same as those of the permanent magnet rotor 12, and they are evenly distributed along the circumference. The length of the permanent magnet rotor 12 along its axis is greater than the length of the stator coil assembly 20 along its axis, with a length difference of 20-40mm. This results in a small section of the permanent magnet rotor 12 near the turntable 16 (right end) being exposed outside the stator coil assembly 20. In the initial state, the small section of the permanent magnet rotor 12 exposed outside the right end of the stator coil assembly 20 is deviated from the enclosure of the coupling ring 31, ensuring no magnetic interference under normal conditions. It also includes a friction head support 32 fixed on the stator support 10. A high-friction friction head 30 is fixed at the end of the friction head support 32. The friction head 30 is made of a composite material of nitrile rubber and metal skeleton, with a static friction coefficient ≥0.8 and a contact pressure ≥100N when the compression is 2-5mm. In the initial state, the friction head 30 presses against the surface of the a turntable 16, thereby suppressing the spontaneous rotation of the a turntable 16 and suppressing the torque ≥100N·m, ensuring that the threaded screw 25 does not move under normal conditions.

[0023] Normal operating status: In normal operating conditions, such as Figure 2 The image above and Figure 3As shown in the figure above, the permanent magnet rotor 12 is exposed outside the stator coil assembly (20) by a small section deviating from the enclosure of the coupling ring 31; and the permanent magnet rotor 13 is completely within the enclosure of the stator coil assembly 21; when the wind turbines 1 and 2 are running normally, the wind energy utilization coefficient Cp is stable at 0.4-0.5 (corresponding to wind speeds of 3-15 m / s), and the rotation of the wind turbines 1 and 2 drives their respective generators 41 and 42 via the transmissions 4 and 5, respectively. Generator 41 and generator 42 are in a decoupled state. At the same time, the friction head (30) suppresses the spontaneous rotation of the integrated structure composed of turntable 16, threaded screw 25 and turntable 17, and the active clutch 14 is locked. Generator 41 and generator 42 operate stably under the control of their respective maximum power point tracking (MPPT) control systems. The MPPT system adopts the incremental conductance method, with a tracking accuracy of ≥98% and a response time of ≤0.3s, and transmits electrical energy to meet the grid connection requirements. Suppose that a single open-circuit fault occurs in either generator A (41) or generator B (42). Open-circuit faults include stator coil open circuits, output cable breaks, and other fault types that prevent current output. This case study will explain the principle in detail using an open-circuit fault occurring solely in generator A (41) as an example: When generator 41 experiences a circuit breaker fault, the Hall current sensor (measurement range 0-500A, accuracy ±1%) installed at the output terminal of stator coil assembly 20 detects that the output current is 0. Simultaneously, the Hall speed sensor (measurement range 0-5000r / min, accuracy ±1r / min) installed on the rotor shaft 7 detects that the speed exceeds the rated speed by 120%. The induction coil of stator coil assembly 20 cannot generate back electromotive force, causing the load on permanent magnet rotor 12 to suddenly drop to zero. At this time, the rotor 1 will accelerate due to the sudden decrease in load, with a speed increase rate reaching 50r / min / s, leading to overspeeding and a very high probability of damage. Bad risks: In conventional technical means, when the sensor detects that the load on the permanent magnet rotor 12 has disappeared and that it is overspeeding, the braking device is usually activated to directly lock the permanent magnet rotor 12, causing the wind turbine 1 to stop rotating. Although this method can solve the overspeed problem of the wind turbine 1, it will cause the static torque and stress of the shaft 7 and the wind turbine 1 to increase. The static torque can reach 3-5 times the normal operating torque, and the stress exceeds 80% of the material yield strength. At the same time, the completely stopped wind turbine 1 will lose its power generation function, resulting in energy waste. This type of wind turbine is generally installed in uninhabited areas, and it usually takes a long time for staff to reach it for maintenance, so there are the above-mentioned hidden dangers. In this scheme, when the sensor detects that the load on permanent magnet rotor 12 has disappeared and overspeed has occurred, the asymmetric fault coupling system will intervene. The intervention signal is issued by the wind turbine main controller, with a control delay of ≤0.1s. The specific intervention process is as follows: First, control the active clutch 14 to enter the locked state. The electromagnetic clutch is energized for ≤0.05s to ensure rapid locking. The hydraulic telescoping device 23 drives the floating translation seat 26 to slide to the left along the guide rail 8. The sliding speed is set to 10mm / s to avoid excessive speed causing component impact. This causes the floating translation seat 26, clutch support 33, active clutch 14, internal thread rotating sleeve 15, threaded screw 25, a turntable 16, b turntable 17, a coupling ring 31, b coupling ring 34, c bearing seat 35, c shaft 27 and b permanent magnet rotor 13 to slide to the left as a whole. The friction head 30 automatically disengages from the a turntable 16. Finally, a small section of the left end of the b permanent magnet rotor 13 moves to the left until it is exposed outside the left end of the b stator coil assembly 21. The a coupling ring 31 moves to the left to surround the originally exposed part of the right end of the a permanent magnet rotor 12, ensuring the magnetic coupling strength.

[0024] At this time, the outer ring of permanent magnets on the right end of permanent magnet rotor 12 and the inner ring of permanent magnets 18 on coupling ring 31 enter a magnetic coupling state. The air gap during coupling is 2-5mm, and the magnetic torque increases as the air gap decreases. Figure 2 Chinese map and Figure 3 As shown in the middle figure, the rotation of permanent magnet 18 (a) drives coupling ring 31 (a) to rotate under the action of magnetic coupling. This causes coupling ring 31, turntable 16 (a), threaded screw 25, turntable 17 (b), and coupling ring 34 (b) to rotate as a whole along the axis. At this time, the threaded screw 25, under the threaded drive of the inner wall of the locked internal threaded rotating sleeve 15, is offset to the right relative to the internal threaded rotating sleeve 15. The offset speed is determined by the thread lead and the rotational angular velocity, usually 1-3 mm / s. This causes coupling ring 31, turntable 16 (a), threaded screw 25, and turntable 17 (b) to rotate. 7 and b coupling ring 34 are offset to the right relative to the internal thread rotating sleeve 15 as a whole until the left end of the internal thread rotating sleeve 15 makes a limiting contact with the a turntable 16. When making the limiting contact, a rubber buffer pad with a thickness of 5mm is provided to avoid rigid collision, so that the threaded screw 25 and the internal thread rotating sleeve 15 can no longer continue thread transmission. At this time, b coupling ring 34 is relatively displaced to the right to surround a small section of the left end of b permanent magnet rotor 13. At this time, the outer ring of permanent magnets on the left end of b permanent magnet rotor 13 and the inner ring of b permanent magnets 19 on b coupling ring 34 also enter a magnetic coupling state.

[0025] Simultaneously, the hydraulic expansion joint 23 drives the floating translation seat 26 to slide adaptively to the left along the guide rail 8. The amount of sliding is adjusted in real time by the displacement sensor, ensuring that the outer ring of permanent magnets on the right end of the permanent magnet rotor 12 and the inner ring of permanent magnets 18 on the coupling ring 31 are always in a state of magnetic coupling. At this time, if Figure 2 The image below and Figure 3 As shown in the figure below; finally, the active clutch 14 is controlled to enter the disengaged state from the locked state. The clutch de-energization time is ≤0.05s. After disengagement, there is no residual torque, so that the internal thread rotating sleeve 15, threaded screw 25, a-disc 16, b-disc 17, a-coupling ring 31, and b-coupling ring 34 form a whole that can rotate freely along the axis. At this time, the whole formed by the internal thread rotating sleeve 15, threaded screw 25, a-disc 16, b-disc 17, a-coupling ring 31, and b-coupling ring 34 acts as an intermediate medium to achieve non-rigid magnetic coupling between a permanent magnet rotor 12 and b permanent magnet rotor 13. Non-rigid coupling can buffer the speed fluctuations of the two rotors, thereby coupling the rotational kinetic energy of a wind turbine 1. The energy is ultimately transferred to the permanent magnet rotor 13 (b), with a kinetic energy transfer efficiency of ≥75%, avoiding energy waste. This allows the permanent magnet rotor 13 to simultaneously receive rotational kinetic energy from both the wind turbine 1 (a) and the wind turbine 2 (b), suppressing overspeed of the wind turbine 1 (a) while comprehensively utilizing its rotational energy. The speed of the wind turbine 1 (a) can be reduced to within 110% of its rated speed within 5-10 seconds. The generator 42 (b) continues to operate stably under the control of the maximum power point tracking (MPPT) control system. At this time, the output power of the generator 42 (b) can be increased to 120%-150% of its rated power (short-term overload capacity ≤30min), thus achieving the coupling repair function in the event of asymmetrical faults in the dual-rotor wind turbine. If wind turbine 1 is still overspeeding, i.e., its speed exceeds 130% of the rated speed, or if generator 42 is overloaded due to coupling, i.e., its output current exceeds 120% of the rated current, the existing braking device in the nacelle 6 can be selectively activated to brake and decelerate. The existing braking device is a disc electromagnetic brake, which adopts a graded braking method (first-stage braking torque 500-1000 N·m, second-stage 1500-2500 N·m) to avoid mechanical shock caused by sudden braking.

[0026] The core principle of this solution is as follows: Normal decoupling and independent operation: Under normal conditions, the permanent magnet rotors (12 and 13) of the two generators (a and b) are spatially separated and driven by their respective wind turbines (1 and 2) through gearboxes (4 and 5), generating electricity independently without interference. A friction braking device 30 ensures that the coupling mechanism will not operate unexpectedly.

[0027] Fault detection and triggering: When the sensor detects that a generator (such as generator a) has lost its load and the rotor is overspeeding due to an open circuit fault, the system triggers the intervention of the asymmetric fault coupling system.

[0028] Axial translation and initial coupling: The system first controls the hydraulic expansion joint 23 to push the entire coupling mechanism (including the clutch, coupling ring, etc.) axially. This causes the coupling ring 31 on the faulty side (side a) to move its permanent magnet 18 to align with the exposed part of the faulty rotor 12, forming initial magnetic coupling. At this time, the rotation of the faulty rotor begins to drive the coupling ring to rotate.

[0029] Threaded drive and secondary coupling: After initial coupling, the rotating coupling ring drives the threaded screw 25 to rotate. Since the internal threaded rotating sleeve 15 is locked by the clutch 14 at this time, the rotating screw will generate axial displacement under the action of the threaded pair. This displacement drives the entire coupling mechanism to continue moving until the coupling ring 34 on the normal side b is also aligned with the exposed part of the normal rotor 13, forming a second magnetic coupling.

[0030] Complete magnetic coupling and energy transfer: Once coupling on both sides is complete, clutch 14 disengages, and the entire coupling mechanism (internal threaded rotating sleeve 15, lead screw 25, turntable 16 / 17, coupling ring 31 / 34) rotates as a free whole. At this point, the rotational kinetic energy of the faulty rotor 12 is transferred non-contactly to the normal rotor 13 through the magnetic coupling medium, enabling the normal generator b to simultaneously absorb the kinetic energy of both wind turbines for power generation.

[0031] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A coupling repair system for asymmetrical faults in a dual-rotor wind turbine, comprising a nacelle (6), an a rotor (1) and a b rotor (2), wherein the a rotor (1) and the b rotor (2) rotate symmetrically at the front and rear ends of the nacelle (6) on the same axis; characterized in that The engine room (6) includes a transmission (4), a transmission (5), a generator (41), a generator (42), and an asymmetric fault coupling system; The a wind turbine shaft (3) of the a wind turbine (1) is connected to the input end of the a gearbox (4), the output end of the a gearbox (4) is connected to the a rotating shaft (7), and the a permanent magnet rotor (12) of the a generator (41) rotates synchronously with the a rotating shaft (7); The b wind turbine shaft (11) of the b wind turbine (2) is connected to the input end of the b transmission (5), the output end of the b transmission (5) is connected to the b rotating shaft (9), and the b permanent magnet rotor (13) of the b generator (42) rotates synchronously with the b rotating shaft (9); Wind turbine a (1) and wind turbine b (2) are counter-rotating wind turbines. Wind turbine a (1) and wind turbine b (2) rotate in opposite directions under wind power. Under the transmission of gearbox a (4) and gearbox b (5), the rotation directions of shaft a (7) and shaft b (9) are the same, which makes the rotation directions of permanent magnet rotor a (12) and permanent magnet rotor b (13) the same. The asymmetric fault coupling system does not intervene under normal conditions. When one of the generators a (41) and b (42) experiences a circuit failure, the asymmetric fault coupling system intervenes, causing the permanent magnet rotor a (12) and the permanent magnet rotor b (13) to be magnetically coupled under the intervention of the asymmetric fault coupling system. The a stator coil assembly (20) of generator a (41) and the b stator coil assembly (21) of generator b (42) are both cylindrical bodies that run through the axis, with the induction coils distributed on the inner wall of the cylinder. One end of permanent magnet rotor (12) is coaxially fixedly connected to shaft (7); the end of permanent magnet rotor (13) away from permanent magnet rotor (12) is coaxially fixedly connected to shaft (27). Shaft (9) and shaft (27) can both move relative to each other along the axial direction and maintain synchronous rotation. The asymmetric fault coupling system includes a guide rail (8) and a floating translation seat (26), the floating translation seat (26) being guided and mating with the guide rail (8) by a slider (24); it also includes a hydraulic telescoping device (23) that can drive the floating translation seat (26) to slide along the guide rail (8); the c-shaft (27) is rotatably mounted on the c-bearing seat (35) by a bearing, the c-bearing seat (35) being fixedly connected to drive the floating translation seat (26); It also includes a clutch support (33) between stator coil assembly (20) and stator coil assembly (21), with a floating translation seat (26) fixedly connected to the upper end of the clutch support (33); an internal threaded rotating sleeve (15) is rotatably mounted on the clutch support (33) via the active clutch (14), and the internal threaded rotating sleeve (15) is coaxial with stator coil assembly (20) and stator coil assembly (21); the active clutch (14) includes two states: locked and disengaged. When the active clutch (14) is locked, the internal threaded rotating sleeve (15) cannot rotate; when disengaged, the internal threaded rotating sleeve (15) can rotate around its own axis. The inner side of the internal threaded rotating sleeve (15) is coaxially threaded with a threaded screw (25). The two ends of the threaded screw (25) are coaxially fixedly connected to a turntable (16) and b turntable (17). The ends of the turntable (16) and b turntable (17) that are far apart from each other are coaxially integrally connected to a coupling ring (31) and b coupling ring (34). The inner rings of the coupling ring (31) and the b coupling ring (34) are respectively arranged in a circular array with a permanent magnet (18) and a permanent magnet (19). The length of the permanent magnet rotor (12) in the axial direction is greater than the length of the stator coil assembly (20) in the axial direction, so that a section of the permanent magnet rotor (12) near the turntable (16) is exposed outside the stator coil assembly (20). In the initial state, the section of the permanent magnet rotor (12) exposed outside the right end of the stator coil assembly (20) is deviated from the enclosure of the coupling ring (31).

2. A coupling restoration system for a dual rotor wind turbine during asymmetric fault conditions according to claim 1, characterized in that: It also includes a friction head support (32) fixed on the stator support (10), and a friction head (30) with a high coefficient of friction is fixed at the end of the friction head support (32). In the initial state, the friction head (30) presses against the surface of the a turntable (16), thereby suppressing the spontaneous rotation of the a turntable (16).

3. A coupling restoration system for a dual rotor wind turbine during asymmetric fault conditions according to claim 2, characterized in that: In normal operation, the permanent magnet rotor (12) is exposed outside the stator coil assembly (20) and deviates from the enclosure of the coupling ring (31); and the permanent magnet rotor (13) is completely within the enclosure of the stator coil assembly (21). The rotation of the impeller (1) and the impeller (2) drives their respective generators (41) and (42) via the transmission (4) and the transmission (5), respectively. The generators (41) and (42) are in a decoupled state. At the same time, the friction head (30) suppresses the spontaneous rotation of the integrated structure formed by the turntable (16), the screw (25) and the turntable (17), and the active clutch (14) is locked. The generators (41) and (42) operate stably under the control of their respective MPPT control systems and transmit electrical energy to the outside.

4. A method of operating a coupling restoration system of a dual-rotor wind turbine during an asymmetric fault according to claim 3, characterized in that: When generator a (41) experiences a circuit failure alone, the active clutch (14) is first locked. The hydraulic telescoping device (23) drives the floating translation seat (26) to slide to the left along the guide rail (8), thereby causing the floating translation seat (26), clutch support (33), active clutch (14), internal thread rotating sleeve (15), threaded screw (25), a turntable (16), b turntable (17), a coupling ring (31), b coupling ring (34), c bearing seat (35), c shaft (27), and b permanent magnet rotor (13) to move to the left as a whole. The friction head (30) automatically disengages from the a turntable (16). Finally The left end of the permanent magnet rotor (13) moves to the left until it is exposed outside the left end of the stator coil assembly (21), and the coupling ring (31) moves to the left until it surrounds the exposed part of the right end of the permanent magnet rotor (12). At this time, the outer ring of the permanent magnet on the right end of the permanent magnet rotor (12) and the inner ring of the permanent magnet (18) of the coupling ring (31) enter a magnetic coupling state. The rotation of the permanent magnet (18) drives the coupling ring (31) to rotate under the action of magnetic coupling, thereby making the coupling ring (31), the turntable (16), the screw (25), the turntable (17) and the coupling ring (34) rotate as a whole along the axis. Under the threaded transmission of the inner wall of the locked internal threaded rotating sleeve (15), the threaded screw (25) shifts to the right relative to the internal threaded rotating sleeve (15), thereby causing the coupling ring (31), the rotating disk (16), the threaded screw (25), the rotating disk (17), and the coupling ring (34) to shift to the right relative to the internal threaded rotating sleeve (15) as a whole, until the left end of the internal threaded rotating sleeve (15) is in contact with the rotating disk (16), so that the threaded screw (25) and the internal threaded rotating sleeve (15) can no longer continue threaded transmission. At this time, the coupling ring (34) has shifted to the right relative to a section surrounding the left end of the permanent magnet rotor (13). At this time, the outer ring of the permanent magnet of the left end of the permanent magnet rotor (13) and the inner ring of the permanent magnet (19) of the coupling ring (34) also enter the magnetic coupling state. At the same time, the hydraulic expansion joint (23) drives the floating translation seat (26) to slide adaptively to the left along the guide rail (8), so that the outer ring of the permanent magnet on the right end of the permanent magnet rotor (12) and the inner ring of the permanent magnet (18) of the coupling ring (31) are always in a magnetic coupling state. Finally, the active clutch (14) is controlled to enter the disengaged state from the locked state, so that the internal thread rotating sleeve (15), the threaded screw (25), the a-rotor (16), the b-rotor (17), the a-coupling ring (31), and the b-coupling ring (34) are a whole that can rotate freely along the axis. At this time, the whole formed by the internal thread rotating sleeve (15), the threaded screw (25), the a-rotor (16), the b-rotor (17), the a-coupling ring (31), and the b-coupling ring (34) serves as an intermediate medium to achieve non-rigid magnetic coupling between the a-permanent magnet rotor (12) and the b-permanent magnet rotor (13).

5. A method of operating a coupling restoration system of a dual rotor wind turbine during an asymmetric fault according to claim 4, characterized in that: If the wind turbine (1) is still overspeeding, or if the generator (42) is overloaded due to coupling, the existing braking device in the nacelle (6) can be selectively activated to brake and decelerate.

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