Inner shaft type speed-increasing transmission pneumatic speed-limiting trapezoidal wing electric control braking vertical shaft wind turbine

Abstract

The invention discloses an inner shaft type speed-increasing transmission pneumatic speed-limiting trapezoidal wing electric control braking vertical shaft wind turbine, which relates to the field of wind power generation, and comprises a bearing outer seat, an inner shaft type wind turbine main shaft, a spoiler, a bearing outer seat, a connecting disc of the bearing outer seat and a machine seat, blades are fixed to the outer ends of the supporting arms and comprise trapezoidal blades and rectangular-trapezoidal combined blades. By means of the method that the retractable spoilers are installed on the blades, the spoilers are opened in strong wind and high rotating speed, the wind wheel is decelerated, and the wind energy obtaining rate of the wind wheel is reduced, so that the output power is controlled, the defect of shutdown at medium and high wind speeds is overcome, continuous operation for power generation can be achieved, the power generation duration is prolonged, and the power generation efficiency is improved. The blade body is of a metal framework and skin structure, so that necessary rigidity and strength of the whole blade are kept, light weight is achieved, and more importantly, spoiler mechanisms of any form can be conveniently designed to be installed in a cavity of the blade.

Description

Technical Field

[0001] This invention belongs to the field of wind power generation, specifically a vertical axis wind turbine with internal shaft speed-increasing transmission, aerodynamic speed-limiting trapezoidal airfoil, and electric control braking. Background Technology

[0002] The existing vertical transmission system with speed-increasing bearings (wind turbine, speed-increasing gearbox, and generator are all coaxial and vertical) uses a bearing housing design. This involves designing a single bearing housing assembly, which is a complex structure consisting of three to four bearings. This results in a large amount of machining work, and the most significant problem is its poor resistance to overturning moments and low overall bending section modulus. In this bearing housing design, the vertically oriented wind turbine sits on the top flange of the bearing housing, and the speed-increasing gearbox (i.e., the speed increaser) is connected to the bottom flange of the bearing housing. The input shaft at the top of the speed increaser fits into the hole in the bearing housing, and the generator shaft then fits into the shaft hole at the bottom of the speed increaser, thus achieving vertical transmission. This design integrates the rotating body inside the bearing and the supporting fixed body outside the bearing into a single assembly. The shaft diameter of the rotating shaft inside the bearing housing must match the shaft diameter of the speed-increasing gear shaft, and the inner diameter of the outer support component of the bearing housing must also match it. While this assembly seems to conform to mechanical conventions, it deviates from the requirements of wind turbines. This not only leads to a complex mechanism but, more importantly, causes the bearing housing to fail to meet the most crucial requirement of wind turbines—anti-overturning capability. This makes the bearing housing prone to breakage under strong winds, causing the wind turbine to fall off the tower. It also results in poor anti-overturning ability. Furthermore, the size of the transmission main shaft inside the bearing housing is constrained by the size of the speed-increasing gearbox shaft, leading to a complex mechanism and high cost.

[0003] Existing vertical axis wind turbines lack flow-limiting and speed-limiting devices on their blades that can be controlled to open and close, and therefore lack methods for controlling speed and power.

[0004] Existing vertical axis wind turbines require increasing rotor resistance using electromagnetic force when the rotor stops, such as by switching on a low-resistance resistor to slow the rotor before short-circuiting the generator. While this has some effect, it easily causes the generator to overheat instantly, which is not a true mechanical friction brake. Therefore, this invention proposes an internal shaft-type speed-increasing transmission electrically controlled braking method to solve the problems mentioned in the background technology. Summary of the Invention

[0005] The purpose of this invention is to provide a vertical axis wind turbine with an internal shaft type speed-increasing transmission aerodynamic speed-limiting trapezoidal airfoil and electric control braking, in order to solve the problems of existing technologies that easily lead to bearing housing breakage in high wind conditions, causing the wind turbine to fall off the tower, poor anti-overturning ability, and the size of the internal transmission main shaft of the bearing housing being limited by the size of the speed-increasing gearbox shaft, resulting in complex mechanisms and high costs; and to solve the problems of existing vertical axis wind turbine blades lacking flow obstruction and speed limiting, and existing vertical axis wind turbine blades being cantilever beams that are not equal strength beams.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a vertical axis wind turbine with an inner shaft type speed-increasing transmission, aerodynamic speed-limiting trapezoidal wing, and electric control brake, comprising a wind turbine main shaft, coupling, connecting disc, speed-increasing gearbox, generator, and electric control brake. The wind turbine main shaft, coupling, connecting disc, speed-increasing gearbox, generator, and electric control brake are arranged sequentially from top to bottom and are all concentric. The bearing outer housing is sleeved outside the inner shaft and connected to the lower half of the inner shaft via a pair of bearings. The wind turbine main shaft, coupling, connecting plate, speed-increasing gearbox, generator, and electric control brake are mounted on the base via the connecting plate and supported by the base. The base provides a support for the entire wind turbine (including the rotor) for on-site assembly. The base is located at the top of the tower column. The wind turbine main shaft is connected to the speed-increasing gear shaft via the coupling. The lower end of the speed-increasing gear shaft is connected to the generator shaft. The wind turbine main shaft is fixedly connected to the support arm, and blades are fixedly connected to the outer end of the support arm.

[0007] The aforementioned vertical axis wind turbine with internal shaft speed-increasing transmission, aerodynamic speed-limiting trapezoidal blades and electric control braking, for situations where the wind-catching area is not very large and the blades are not very long, adopts a single arm to reduce rotational inertia, simplify the structure, and reduce costs. More importantly, the entire blade is designed as a trapezoid to increase the bending section modulus of the root of the entire blade, which serves as a cantilever beam component. The cantilever beam is designed as a beam of equal strength to resist the bending moment load caused by centrifugal force under strong winds and high speeds.

[0008] The skin surface is cut with openings, and a skin baffle is installed inside the openings.

[0009] The blades include trapezoidal blades and rectangular-trapezoidal combined blades. In particular, trapezoidal blades are significant for increasing the strength of single-arm blades (a type of wind turbine structure).

[0010] Preferably, the rectangular-trapezoidal combined blade is provided with a trailing edge baffle, which can be controlled to swing on the blade body.

[0011] Preferably, the blade body includes two U-shaped longitudinal beams, and a transverse rib is provided between the two U-shaped longitudinal beams. The U-shaped longitudinal beams and the transverse rib form a blade skeleton. The blade skeleton is hollow inside, and the outer surface of the blade skeleton is covered with a skin. The skin is fixedly connected to the blade skeleton by riveting or welding to form a strong cavity enclosure.

[0012] Preferably, when the support arm consists of two sets (upper and lower supports are needed to support the blade when the blade is very long), a rectangular-trapezoidal combined blade is provided, with the rectangular part fixedly connected to the support arm and the trapezoidal part located at the top and bottom of the rectangular part.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. The design of the wind turbine shaft diameter in this invention is independent of the speed-increasing gearbox shaft diameter. The overturning moment is borne solely by the wind turbine main shaft, which is supported by the bearing outer housing through the bearing. The wind turbine main shaft is directly connected to the speed-increasing gearbox shaft via a coupling, simplifying the transmission structure. Furthermore, the wind turbine main shaft diameter can be arbitrarily determined according to the size of the wind turbine without having to be close to the gearbox shaft diameter, facilitating the use of a larger shaft diameter to increase the bending section modulus of the main shaft and the bearing outer housing, thereby increasing the overall machine's ability to resist horizontal thrust. The shape and size of the wind turbine main shaft can be determined as needed through force verification, and the dimensions of the bearings and bearing outer housing can be determined simultaneously. The structure is simple, and the verified wind turbine main shaft can meet the requirements for resisting overturning moments under strong winds.

[0015] 2. This invention utilizes a method of installing retractable baffles on the blades to alter the wind turbine's wind energy harvesting rate, thereby controlling the output power. Experimental results have shown significant effectiveness, filling a gap in existing vertical axis wind turbines. Specifically, the baffles deploy during strong winds, forcing the turbine to slow down, thus eliminating the need to shut down the turbine for safety at medium to high wind speeds. This allows for continued operation and power generation at medium to high wind speeds, increasing power generation time. The blades employ a metal frame and skin integrated structure, maintaining necessary rigidity and strength while achieving lightweight design. More importantly, it facilitates the design of any type of baffle mechanism to be installed within the blade cavity.

[0016] 3. This invention, through the design of a double-sided trapezoidal blade body (both sides are trapezoidal when viewed from two mutually perpendicular surfaces), is suitable for use in single-arm wind turbines. Existing H-type vertical axis wind turbines have blades that are cantilever beam components. When the wind turbine rotates at high speeds, the blades are subjected to large bending moment loads at the junction with the arm, and the blades are prone to failure at this junction, i.e., the blade root. This invention designs the blades as trapezoids, which strengthens the bending section modulus at the junction of the blade and the arm, i.e., the point where the blade stress is the greatest, without reducing aerodynamics. It also reduces the rotational inertia as a whole and improves the acceleration performance of the wind turbine.

[0017] 4. This invention employs an electrically controlled brake—a mechanical brake—to apply mechanical friction braking to the generator shaft. Compared to existing short-circuit braking (i.e., electric braking), which relies on a large instantaneous current in the generator coil, this method provides stronger braking force and avoids subjecting the generator coil to excessive current. This brake applies friction braking simply by being energized. Since the braking torque is applied to the wind turbine via a speed-increasing gearbox, based on the principle that the resistance ratio of the gears equals the speed ratio, the brake can apply a smaller braking torque to a larger wind turbine torque. This results in a better braking effect than electric braking.

[0018] All the technical aspects of this invention are interconnected and work in coordination; none can be omitted, thus forming a novel vertical axis wind turbine with coordinated operation. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0020] Figure 2 This is a cross-sectional view of the trapezoidal blade in Embodiment 1 of the present invention;

[0021] Figure 3 This is a schematic diagram of the structure of Embodiment 2 of the present invention;

[0022] Figure 4 This is a cross-sectional view of the rectangular-trapezoidal combined blade in Embodiment 2 of the present invention;

[0023] Figure 5 For the present invention Figure 1 A magnified view of a portion of the image;

[0024] Figure 6 This is a schematic diagram of the trailing edge baffle of the present invention; it can be used in various embodiments.

[0025] Figure 7 This is a schematic diagram of the structure of the skin baffle plate in this invention; all embodiments are applicable.

[0026] Figure 8 This is a schematic diagram of the skeleton and skin structure of the blade of the present invention, which can be used in all embodiments and is required for blades of various shapes;

[0027] Figure 9 This is a schematic diagram of the blade skeleton in this invention. It can be used in all embodiments and is required for blades of various shapes.

[0028] Figure 10 This is a top view of the wind turbine of the present invention, showing the relationship between the blades and the support arm, main shaft, and bearing housing, and showing the position of the blades in the wind turbine;

[0029] Figure 11 A diagram showing the wind turbine design with pure rectangular blades and the overall structure of the unit.

[0030] In the picture:

[0031] 1. Bearing; 2. Bearing housing; 3. Wind turbine main shaft; 4. Connecting disc; 5. Coupling; 6. Speed-increasing gearbox; 7. Speed-increasing gear shaft; 8. Generator; 9. Generator shaft; 10. Base; 11. Electric control brake; 12. Brake mounting plate; 13. Trapezoidal blade; 14. Bolt; 15. Support arm; 16. Rectangular-trapezoidal combined blade; 17. Blade; 18. Trailing edge baffle; 19. Skin baffle; 20. U-shaped longitudinal beam; 21. Transverse rib; 22. Skin. Detailed Implementation

[0032] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0033] As attached Figure 1 Appendix Figure 2 Appendix Figure 5 Appendix Figure 7 To be continued Figure 10 As shown:

[0034] A vertical axis wind turbine with an inner shaft type speed-increasing transmission, aerodynamic speed-limiting trapezoidal wing, and electric control braking includes a bearing outer housing 2, a wind turbine main shaft 3 with an inner shaft type rotor, a coupling 5, a connecting plate 4, a speed-increasing gearbox 6, a generator 8, and an electric control brake 11. The wind turbine main shaft 3, coupling 5, connecting plate 4, speed-increasing gearbox 6, generator 8, and electric control brake 11 are arranged concentrically from top to bottom. The bearing outer housing 2 is sleeved outside the inner shaft and rotatably connected to the lower half of the inner shaft through a pair of bearings 1. The wind turbine main shaft 3, coupling 5, connecting plate 4, speed-increasing gearbox 6, generator 8, and electric control brake 11 are arranged concentrically from top to bottom. Section 5, connecting plate 4, speed-increasing gearbox 6, generator 8 and electric control brake 11 are mounted on base 10 via connecting plate 4 and fixed by bolts 14 and supported by base 10. Base 10 provides a support for the entire wind turbine, including the turbine body and rotor, to be assembled on-site. Base 10 is located at the top of the tower column. Wind turbine main shaft 3 is connected to speed-increasing gear shaft 7 via coupling 5. The lower end of speed-increasing gear shaft 7 is connected to generator shaft 9. Wind turbine main shaft 3 is fixedly connected to support arm 15. Blades 17 are fixedly connected to the outer end of support arm 15.

[0035] During operation, the airflow generates aerodynamic force on the blades 17, propelling them to rotate around the wind turbine's main shaft 3. The blades 17, via the support arm 15, drive the wind turbine's main shaft 3 to rotate, converting wind energy into mechanical energy (shaft power). The wind turbine's main shaft 3 transmits the rotational torque to the speed-increasing gear shaft 7 via the coupling 5, which in turn increases the rotational speed through the planetary gear set inside the gearbox (the speed-increasing ratio can be designed according to the rated speed of the generator 8). The increased rotational power is then transmitted through the speed-increasing gear shaft 7 to the generator shaft 9 of the generator 8, driving the internal rotor of the generator 8 to rotate. The rotor cuts... The stator magnetic field lines generate an induced electromotive force, completing the conversion of "wind energy → mechanical energy → electrical energy". When the wind speed exceeds the rated value (e.g., 12 m / s, which can be set as needed), and the wind turbine speed and output power exceed the rated values, the control system causes the baffle to flip up (open action) to limit the wind turbine speed and output power. When the wind speed is less than the rated wind speed, the control system causes the baffle to retract, and the baffle performs a return action to restore the blade 17 to its original position. By limiting the wind turbine speed using aerodynamic principles, the gap of no aerodynamic speed limiting is filled in the vertical axis wind turbine.

[0036] When maintenance is required, the control system sends a signal to the electric brake 11, causing the fixed plate and moving plate of the electric brake 11 to engage, making close contact and generating friction. The generator shaft 9, the speed-increasing gearbox 6 shaft, and the electric brake 11 are all keyed. The resistance of the brake will limit the rotation of the speed-increasing gearbox 7, the coupling 5, and the wind turbine main shaft 3, thus achieving braking and stopping. Compared with the existing short-circuit electric braking, the mechanical friction braking of this embodiment has stronger braking force, which can overcome the disadvantage of the short-circuit method not being able to stop the vehicle under strong winds, and avoids the generator 8 bearing excessive current. Based on the principle that the ratio of the resistance torque of the input shaft and the output shaft of the gear transmission is equal to the speed ratio multiple, a friction braking device is installed on the high-speed shaft (the generator shaft and the high-speed shaft of the speed-increasing gearbox are at the same speed), resulting in higher braking efficiency and the ability to brake the wind turbine with a small braking torque.

[0037] The brake mounting plate 12 provides fixed support for the fixed plate of the electric brake 11, preventing the component from shifting due to the reaction force during braking; the top of the speed-increasing gearbox 6 is fixedly connected to the connecting plate 4 by bolts 14, forming a coaxial transmission of "speed-increasing gearbox 6-generator 8-electric brake 11".

[0038] In one embodiment of the present invention, the blade 17 is arranged in a trapezoidal shape, namely a trapezoidal blade 13, in order to optimize the stress structure of the blade 17. The principle is to transform the cantilever beam into a beam of equal strength, thereby providing a method to make the stress distribution of the blade 17 more uniform.

[0039] In one embodiment of the present invention, the blade 17 adopts a rectangular-trapezoidal combination, the trapezoidal blade 13 is used for a single arm 15, and the rectangular-trapezoidal combination blade 16 is used for a double arm 15.

[0040] The blade 17 (whether it is a trapezoidal blade 13, a rectangular-trapezoidal combination blade 16, or a single rectangle) is constructed using a sheet metal method. The purpose is to provide a method to achieve lightweighting while ensuring the strength and rigidity of the aerodynamic component—the blade 17. The blade 17 includes two or more U-shaped longitudinal beams 20, and a transverse rib 21 is provided between the two U-shaped longitudinal beams 20. The shape of the transverse rib 21 is not limited. The U-shaped longitudinal beams 20 and the transverse rib 21 form the skeleton of the blade 17. The inside of the skeleton is a cavity to accommodate the aerodynamic speed limiting device. The outer surface of the skeleton is covered with a skin 22, which is fixedly connected to the skeleton by riveting or welding to form a high-strength integrity.

[0041] During operation, the cross-sectional shape of the U-shaped longitudinal beam 20 can effectively resist the centrifugal force and wind load when the blade 17 rotates, and the transverse rib 21 further enhances the overall stability of the frame and avoids frame deformation; the hollow design greatly reduces the weight of the blade 17, reduces the starting wind speed of the wind turbine, and improves the power generation capacity in low wind speed environments.

[0042] In one embodiment of the present invention, a portion of the skin 22 is used as a baffle plate, which is called "skin baffle plate 19".

[0043] When the wind speed exceeds the rated value, the skin deflector 19 activates, opening on the surface of the blade 17 (the opening angle can be driven by a motor or hydraulic system). At this time, the opening of the skin deflector 19 will disrupt the lift on the blade 17, thus reducing the aerodynamics of the blade 17 and increasing the air resistance on the surface of the blade 17. This reduces the wind energy capture rate, keeping the rotor speed within a safe range (avoiding overspeed damage to the generator 8). This allows for continuous power generation without shutdown even in strong winds (up to 25 m / s), overcoming the shortcomings of existing vertical axis wind turbines that rely on resistance unloading and short-circuit braking methods, which require braking protection at wind speeds of 15-16 m / s, resulting in significant loss of the generator 8 and increasing power generation.

[0044] Example 2: This example is basically the same as the previous example, except for the structural design of the support arm 15 and the blade 17, as detailed below. Figure 3 , Figure 4 , Figure 7 As shown: The wind turbine main shaft 3 is fixedly connected to two sets of arms 15 (when the blade 17 is very long, upper and lower arms 15 are needed to support the blade 17). The outer end of the arm 15 is provided with a rectangular-trapezoidal combined blade 16. The rectangular-trapezoidal combined blade 16 includes a rectangular part and a trapezoidal part. The rectangular part is fixedly connected to the arm 15. The trapezoidal part is located at the upper and lower ends of the rectangular part. The rectangular part and the trapezoidal part are fixedly connected. The trailing edge of the rectangular-trapezoidal combined blade 16 is provided with a trailing edge baffle 18, which can be controlled to swing on the blade 17. Both the rectangular-trapezoidal combined blade 16 and the trapezoidal blade 13 can be equipped with baffle actuation devices, such as the trailing edge baffle 18 or the skin baffle 19.

[0045] During operation, the power and horizontal thrust load of the blade 17 are transmitted to the wind turbine main shaft 3 through the support arm 15. The force on the main shaft is a concentrated force, which not only transmits torque but also creates a bending moment on the bearing 1. Since the wall thickness and outer diameter of the main shaft can be designed entirely based on the load of the main shaft itself, the overturning moment (bending section modulus) of the main shaft can be significantly improved. Moreover, the structure is simple and significantly provides high reliability of the main shaft and the entire machine.

[0046] The trapezoidal portion of the rectangular-trapezoidal combined blade 16 is located at the top and bottom of the rectangular portion. The trapezoidal structure makes the blade 17 equivalent to a beam of equal strength. At the joint of the support arm 15, the bending section modulus is significantly improved, solving the problem of easy breakage at the joint of the existing H-type blade 17 and support arm 15. At the same time, the trapezoidal portion can reduce the mass at the end of the blade 17, reduce the rotational inertia of the wind turbine, shorten the acceleration time of the wind turbine, improve the speed response speed when the wind speed fluctuates, and reduce the bending moment at the blade arm joint caused by centrifugal force.

[0047] Both the trailing edge baffle 18 and the skin baffle 19 can rotate around the hinge. When the wind speed is below the rated value (e.g., 12 m / s), the trailing edge baffle 18 or the skin baffle 19 retracts and becomes flush with the surface of the blade 17, without affecting the aerodynamic performance of the blade 17. When the wind speed is 13-15 m / s or above, the trailing edge baffle 18 or the skin baffle 19 rotates outward at a certain angle to increase air resistance. When the wind speed is 15-18 m / s, the trailing edge baffle 18 or the skin baffle 19 opens to a larger angle, further increasing the resistance. By adjusting the baffle angle, a precise match between wind speed and rotation speed can be achieved, avoiding excessive wind energy gain due to increased wind speed.

[0048] The foregoing has described some typical embodiments of the present invention. Undoubtedly, those skilled in the art, after understanding the meaning of the method of the present invention, can apply it in various different ways. Therefore, the above drawings and descriptions are illustrative and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A vertical axis wind turbine with an internal shaft type speed-increasing transmission, aerodynamic speed-limiting trapezoidal wing, and electric braking, characterized in that: The system includes a bearing housing (2), a wind turbine main shaft (3) with an inner shaft type wind turbine, a coupling (5), a connecting disc (4), a speed-increasing gearbox (6), a generator (8), and an electric control brake (11). The wind turbine main shaft (3), coupling (5), connecting disc (4), speed-increasing gearbox (6), generator (8), and electric control brake (11) with the inner shaft type wind turbine are arranged from top to bottom and are all concentric. The bearing housing (2) is sleeved outside the inner shaft and is rotatably connected to the lower half of the inner shaft through a pair of bearings (1). The wind turbine main shaft (3), coupling (5), connecting disc (4), speed-increasing gearbox, and speed-increasing gearbox are all rotatably connected to the inner shaft. (6) The generator (8) and the electric control brake (11) are mounted on the base (10) via the connecting plate (4) and fixed by bolts (14). The base (10) is used to provide a support for the entire wind turbine, including the body and the rotor, to be assembled on-site. The base (10) is located at the top of the tower column. The wind turbine main shaft (3) is connected to the speed-increasing gear shaft (7) via the coupling (5). The lower end of the speed-increasing gear shaft (7) is connected to the generator shaft (9). The wind turbine main shaft (3) is fixedly connected to the support arm (15). The outer end of the support arm (15) is fixedly connected to the blade (17).

2. The vertical axis wind turbine with internal shaft type speed-increasing transmission, aerodynamic speed-limiting trapezoidal wing, and electric braking according to claim 1, characterized in that: The blade (17) includes a trapezoidal blade (13) and a rectangular-trapezoidal combined blade (16), wherein the trapezoidal blade (13) is used for a single arm (15) and the rectangular-trapezoidal combined blade (16) is used for a double arm (15).

3. The vertical axis wind turbine with internal shaft type speed-increasing transmission, aerodynamic speed-limiting trapezoidal wing, and electric braking according to claim 1, characterized in that: The electric brake (11) is fixedly connected to the brake fixing plate (12), and the coupling (5) is fixedly connected to the speed-increasing gear shaft (7) and the wind turbine main shaft (3).

4. The vertical axis wind turbine with internal shaft type speed-increasing transmission, aerodynamic speed-limiting trapezoidal wing, and electric braking according to claim 1, characterized in that: The blade (17) includes a U-shaped longitudinal beam (20), and transverse ribs (21) are provided between the U-shaped longitudinal beams (20). The U-shaped longitudinal beams (20) and transverse ribs (21) form the blade (17) skeleton. The blade (17) skeleton is hollow inside. The outer surface of the blade (17) skeleton is covered with a skin (22). The skin (22) is fixedly connected to the blade (17) skeleton by riveting or welding.

5. The vertical axis wind turbine with internal shaft type speed-increasing transmission, aerodynamic speed-limiting trapezoidal wing, and electric braking according to claim 4, characterized in that: The skin (22) has an opening cut into its surface, and a skin baffle (19) is provided inside the opening. The skin baffle (19) is part of the skin (22). A trailing edge baffle (18) is provided at the trailing edge of the blade (17). Both the skin baffle (19) and the trailing edge baffle (18) can be controlled to swing on the blade (17).

6. The vertical axis wind turbine with internal shaft type speed-increasing transmission, aerodynamic speed-limiting trapezoidal wing, and electric braking according to claim 2, characterized in that: The rectangular-trapezoidal combined blade (16) includes a rectangular portion and a trapezoidal portion and their combination.

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