HK1165845A - Vertical axis wind turbines - Google Patents

Description

Vertical axis wind turbine

The invention is a divisional application of patent application with the international application date of 2006, 5 and 15, the international application number of PCT/US2006/019326 and the Chinese national application number of 200680016461.1.

RELATED APPLICATIONS

This application claims priority to U.S. provisional application 60/681,210 entitled "improved vertical axis wind turbine" filed on 13.5.2005, the contents of which are hereby incorporated by reference in their entirety.

Statement regarding federally sponsored research and development

The invention was accomplished under contract number No. de-AC02-05CH11231 during work supported by the united states energy sector. The government has certain rights in this invention.

Background

Technical Field

The present invention relates generally to wind turbines, and more particularly to vertical axis wind turbines.

Description of the Related Art

Most wind turbine literature relates to horizontal axis wind turbines, which appear to be the main form of wind energy production due to the better efficiency of the blades. This high blade efficiency is a result of the high tip speeds, however, such high speeds can result in increased noise and increased damage upon impact with the blade during operation.

Many vertical shaft designs with low blade speeds have been proposed for many years, but none have achieved widespread use despite the advantages that low blade speeds offer. The main problems relate to structural resonance failure, high production costs and the requirement to be placed on the ground very close to the low wind speed sites. The energy output is reduced due to the low wind speed close to the ground.

Many vertical axis construction and cost issues are associated with attempting to recapture additional wind energy by adjusting the blade angle of attack. Others have attempted to modify the structural shape to accommodate high wind speeds or gusts. Such designs inevitably lead to increased hardware complexity, with attendant increased failure rates and production costs.

Disclosure of Invention

The embodiments described herein address several shortcomings of the prior art and use modern engineering and system modeling tools to analyze overall system behavior in multiple wind forms.

One embodiment of the invention is a vertical axis wind turbine. The embodiment comprises the following steps: at least one airfoil, wherein the airfoil comprises an upper surface, a lower surface, and a centerline, wherein a distance from the upper surface to the centerline is the same as a distance from the lower surface to the centerline across a length of the airfoil.

Yet another embodiment is a vertical axis wind turbine rotor, comprising: an upper ring, a middle ring, and a lower ring; a plurality of upper airfoils disposed vertically between said upper ring and said middle ring; and a plurality of lower airfoils disposed vertically between the lower ring and the middle ring.

Yet another embodiment is a vertical axis wind turbine, comprising: a vertical axis rotor comprising at least one wing and configured to be rotated by wind; and an air regulator controlled by centrifugal force from the rotor and configured to reduce a rotational speed of the rotor by moving a position of the at least one airfoil.

Neither the summary nor the following specific examples are intended to limit the invention. The invention is defined by the claims.

Drawings

FIG. 1 shows an embodiment of a vertical axis wind turbine system interfaced with an alternator, a control system and a battery.

FIG. 2A shows a schematic front view of an embodiment of a four-bladed vertical axis wind turbine system.

FIG. 2B shows a schematic side view of an embodiment of a four-bladed vertical axis wind turbine system.

FIG. 2C shows a different angle schematic side view of an embodiment of a four-bladed vertical axis wind turbine system.

FIG. 2D shows a schematic plan view of an embodiment of a four-bladed vertical axis wind turbine system.

FIG. 3 is a schematic view of a blade unit used with certain embodiments of a vertical axis wind turbine.

FIG. 4A is a cross-sectional schematic plan view of an embodiment of an airfoil showing openings and blunt narrow ends for two structural elements.

FIG. 4B is a cross-sectional view of an embodiment of an airfoil for use with a wind turbine system.

FIG. 4C is a graph of fluid dynamics test results showing that a blunt trailing edge produces less turbulence than a sharp edge rotated through 180 degrees.

FIG. 5 illustrates one embodiment of a six-bladed vertical axis wind turbine engaged with an alternator.

FIG. 6 is a schematic side view of an embodiment of a six-bladed vertical axis wind turbine.

FIG. 7 is a top view of an embodiment of a six-bladed vertical axis wind turbine.

FIG. 8 is a top view of an embodiment of an aerodynamic adjuster assembly.

FIG. 9 is a cross-sectional view of an embodiment of an aerodynamic adjuster assembly.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

According to one embodiment, a vertical axis wind turbine is disclosed having a rotor with blades designed and tested to produce maximum torque at approximately 2.5 times the wind speed. In one embodiment, the blades have a fixed angle of attack such that the turbine starts up on itself at wind speeds of 2-4m/s and produces rated power at 11m/s wind speed. The wind turbine of this embodiment captures energy in all wind directions and in gust conditions without requiring any modification to the basic shape of the turbine. They can also be arranged in this way: avoiding the need to pass through any central shaft of the turbine. This arrangement utilizes aerodynamic forces to maintain the proper shape and continues to rotate about the proper axis of rotation.

Also disclosed herein are aerodynamic force modulators, such as known aerodynamic spoilers and aerodynamic braking devices. In one embodiment, the aerodynamic force modulator is fabricated as a top cross-beam of a rotor in a wind turbine. These regulators are actuated by centrifugal force and spring energy to control the maximum rotational speed of the rotor, thus preventing turbine failure due to excessive rotational speed.

In a further embodiment, the wind turbine comprises a mechanical braking device that can be activated at a desired moment to slow down or stop the rotor. In one embodiment, the wind turbine includes a rotor connected to a rotating tube. The rotating tube connects the wheel shaft at the base of the turbine, which contains space for an axial gap alternator and/or an additional mechanical braking system to control angular velocity. Such mechanical braking systems allow the turbine to be stopped and serviced at high wind speeds. When operating with the axial gap alternator, the wind generator essentially comprises a single moving part, with suitable dimensioning of the alternator, an output voltage close to the standard line voltage for local use can be obtained.

Vertical axis wind turbines: four-bladed embodiment

FIG. 1 shows an example embodiment of a wind turbine system 1 comprising a rotor 100 mounted on a rotating pipe 2, whereby rotation of the rotor 100 causes rotation of the pipe 2. The base of the tube 2 engages the alternator 200 so that rotation of the tube 2 causes rotation of the alternator 200. The alternator 200 is electrically connected to the control system 300 and the battery 400. As shown, the rotor 100 is in an elevated position with respect to the ground to gain access to higher wind speeds. The rotor 100 is connected to an alternator 200 to convert mechanical energy from the rotor into electrical energy. The alternator 200 is connected to a control system 300, the control system 300 being connected to a battery 400 for storing the electrical energy generated by the wind turbine 100. The control system 300 controls the current to the battery. Of course, it is realized that the wind turbine system 1 may also be coupled directly or indirectly to a power grid to provide energy to the power grid instead of a battery. Furthermore, it is also possible to use the rotor 100 for mechanically rotating a pump or other device for operation.

Fig. 2A shows a schematic front view of a four-bladed vertical shaft rotor 100, fig. 2B shows a schematic side view of the four-bladed vertical shaft rotor 100, and fig. 2C shows schematic side views of the four-bladed vertical shaft rotor 100 at different angles. Fig. 2D shows a top view of the four-bladed vertical axis rotor 100.

As shown in fig. 2A-2D, the vertical axis rotor 100 comprises four angled blade units 10, 20, 30 and 40. Although these four-bladed units comprise the main functional elements of the four-bladed embodiment shown in fig. 2A-2D, any integer number of more than two bladed units is feasible, given the physical space and the degree of aerodynamic capture. Moreover, although certain angles are used in the embodiments described herein, embodiments of the present invention are not limited to any particular angle, but rather relate to the configuration of the blades relative to each other.

Each blade unit 10 includes a lower blade assembly 12 and an upper blade assembly 15. The two blade assemblies consist of the same or substantially the same airfoil 18, which airfoil 18 is connected to two internal tubes (not shown) that carry structural loads and provide rigidity and optimum angle of attack for the blade. The upper blade assembly 15 has extension tubes 25 and 27 that allow for direct connection to the top connection point, the upper joint 50. The horizontal return elements 17 function to return from the lower blade assembly 12 to the lower connecting axle 35 where the rotational force is transferred to the alternator 200 or other energy conversion mechanism (not shown). The lengths of the extension pipes 25 and 27 are such that: the blade unit 10 is provided with an included angle of approximately 145 degrees between the lower blade assembly 12 and the upper blade assembly 15. The 145 degree angle allows the overall shape of the wind turbine to be constructed, although other suitable angles may be used. All of the horizontal return member 17, the lower blade assembly 12, the upper blade assembly 15, the extension tubes 25 and 27, and the axle 35 are adapted to be interconnected by substantially rigid connectors to produce the blade unit 10 shape shown in fig. 2A-2D.

In the embodiment shown in fig. 2A-2D, four blade units 10, 20, 30 and 40 are connected to the top joint 50 and the lower joint 35 by each blade unit being rotationally arranged around the plane of rotation at about 90 ° to each other and by each two blade assemblies being rotated in the vertical direction by 180 ° relative to each other. As best shown in fig. 2B, in this arrangement, the blade units 10 and 20 are 180 ° opposite each other. As best shown in fig. 2C, the inverted blade units 30 and 40 are also 180 ° opposite each other. By interconnecting the substantially rigid joints of these components of each blade unit, the vertical shape of the wind turbine is built up.

As best shown in fig. 2B, the wing 18 mainly comprises a lower horizontal return element 17. These wings 18 act as fairings to reduce aerodynamic drag. These airfoils 18 may be mounted at a small non-zero angle of attack to facilitate management of vertical force loads on the bearings without generating substantial rotational drag. For example, the small non-zero angle of attack may be +/-5 degrees. The lower horizontal return member 17 completes the connection of the blade unit 10 to the lower joint 35. A similar lower horizontal return element 23 performs the same function by the blade unit 20.

As shown in fig. 2C, four movable airfoils 22a-d are located on the upper horizontal return element 19. An upper horizontal return element 19 is used in each of the vane units 30 and 40 and completes the connection of these vane units to the tip junction 50. The movable airfoils 22a-d are energized by the rotation of the rotor 100 so that the airfoils articulate to a greater degree as the rotor rotates faster. In one embodiment, the articulation of the movable airfoils 22a-d is controlled by weights 5 that move radially in response to the rotational forces acting on the rotor 100. When the rotor 100 rotates, the weights 5 move outwards and change the position of the movable wing 19 via a mechanical coupling. Thus, as the rotor 100 rotates at a faster speed, the weights 5 are gradually moved outwards by centrifugal force, thus causing the movable airfoils 19 to change position and become drag inducing devices. This causes the rotor 100 to reduce its rotational speed.

In this embodiment, the movable airfoils 22a and 22b articulate in opposite directions, resulting in increased drag as the surface area increases. Similarly, movable wings 22c and 22d articulate in opposite directions. Thus, when the rotor turns faster, these wings act as a regulator, or air brake, to slow the rotation of the rotor. The excitation of these movable airfoils 22a-d is most simply achieved by internal springs and centrifugal actuators controlled by the movement of the weights 5, and which maintain the rotational speed of the rotor 100 at or below a maximum limit.

Returning to FIG. 2A, it shows the movable airfoils 22A-d in a situation where the wind turbine is rotating very quickly and requires deceleration. The movable airfoils 22a-d are configured at opposing angles to produce approximately zero vertical force on the rotor 100 while providing drag to slow the turbine. If desired, the movable airfoils 22a-d may also be configured in the same direction to provide vertical force while reducing the same drag. A plurality of movable airfoils may also be arranged on a horizontal plane to control the rotational speed. Thus, embodiments of the invention are not limited to this particular configuration or number of movable airfoils.

The guy wires 13 are arranged between the blade units 10 and 20. Similarly, the guy wires 14 are disposed between the blades 30 and 40. The guy wires 13 and 14 function as extensible members that are tensioned by the rotational load caused by the centrifugal force from the paired blade assemblies as they rotate.

In some embodiments, the lower connecting hub 35 may be connected to a hub that houses the mechanical brake, the axial gap alternator, and the connection of the tower (not shown) that is comprised of somewhat conical nesting sections. Also, each nesting portion may have at least two protrusions at the tip along the tube near the end of the narrow taper to limit the travel of the added portion and set the amount of overlap from one portion to another to be that which is allowed for the strength of the entire tower. Thus, the tower may be of variable height to accommodate the mounting point, and the tower section may be easily transported in smaller vehicles.

FIG. 3 is a schematic view of a blade unit 10 used with certain embodiments of the vertical axis wind turbines described herein. In some embodiments, the blade unit 10 is foldable. With the example embodiment of the blade unit 10 shown in fig. 3, the lower blade assembly may be folded along the path of arrow a to contact the lower horizontal return element 17. The upper blade assembly 15 may then be folded along the path of arrow B. As shown, the angle between the return member 17 and the lower blade assembly 12 is 90 degrees with an error of plus or minus 5 degrees. The angle created by lower blade assembly 12 and lower horizontal return member 17 is 141.30 degrees, which may be plus or minus 5 degrees. Of course, embodiments of the invention are not limited to any of these particular angles, and other configurations of the rotor are contemplated.

Wing

Fig. 4A is an airfoil 18 having a leading edge 24 and a rounded trailing edge 16. The cross-section has two holes 21a, b for inserting structural elements to stabilize the wing 18 and carry these loads with minimal deformation of the wing 18. Other embodiments of these structural elements are also within the scope of the present invention. Exemplary structural elements are extension tubes 25 and 27 (fig. 2A). In one embodiment, the wing 18 may be made of a foam filled composite or metal with a tie-down beam. Which is suitable for extrusion or pultrusion manufacturing processes.

As shown, the design of the airfoil 18 can be described by the relationship with respect to a centerline x-axis drawn across the airfoil 18 and a vertical y-axis drawn across the airfoil. As shown in fig. 4B, upper surface 350 and lower surface 355 are maintained at a constant distance from the x-axis along the length of airfoil 18. Thus, at any point along upper surface 350, the distance from upper surface 350 to centerline x is equal to the distance from lower surface 355 to centerline x.

FIG. 4B is a schematic plan view of an embodiment of an airfoil for use in a wind turbine system. Referring to FIG. 4B, one embodiment of the shape of the airfoil 18 may be designed using the coordinate table shown in Table 1 below. Where 'b' is the chord length, 'c' is the maximum thickness of the profile, and b/c is constant.

TABLE 1

X and Y coordinates of an airfoil

x/b	0	0.001	0.002	0.003	0.004	0.005	0.006	0.007	0.008	0.009
											y/c	0	0.035078	0.049608	0.060757	0.070156	0.078436	0.085923	0.092807	0.099215	0.105233
x/b	0.01	0.02	0.03	0.04	0.05	0.051928	0.06	0.07	0.08	0.09
											y/c	0.110926	0.156873	0.192129	0.221852	0.248038	0.252774	0.271178	0.291407	0.309567	0.326335
x/b	0.1	0.15	0.2	0.25	0.3	0.35	0.4	0.45	0.5	0.55
											y/c	0.342234	0.408723	0.454353	0.482354	0.496254	0.5	0.495243	0.480917	0.457402	0.427095
x/b	0.6	0.65	0.7	0.75	0.8	0.85	0.9	0.95	0.986813	1
											y/c	0.392118	0.353088	0.310766	0.26637	0.220631	0.173868	0.127219	0.081241	0.045298	0

Although FIG. 4B and the above-described coordinate tables illustrate one exemplary embodiment of an airfoil 18 for use with the wind turbines described herein, alternative shapes that generate lift forces may be used. Because of its high efficiency at low wind speeds, the exemplary shape of airfoil 18 may be selected for certain embodiments discussed herein. For example, low wind speeds may be 3-4 meters/second. The aerodynamic coefficient of the airfoil 18 of this embodiment is such that: the vertical axis rotor 100 starts itself when the wing 18 is fixed at an angle of attack of 0-5 deg.. However, in one embodiment, the angle of attack is fixed at 2 °. The trailing edge 16 of the wing is rounded to avoid turbulence as it does during each revolution when the wing 18 moves backwards into the wind.

FIG. 4C is a graph of fluid dynamic test results showing that the blunt trailing edge 16 produces less turbulence than a sharp trailing edge moving through a 180 degree rotation. The graph shows the results of a hydrodynamic test comparing the drag coefficient of a wing with a blunt trailing edge (blurry squares) with a similar wing with a sharp trailing edge (blurry triangles). The blunt trailing edge reduces turbulence potential and dynamic structural loading, both of which increase the efficiency of the turbine.

Vertical axis wind turbines: six-bladed embodiment

Fig. 5 is an embodiment of a six-bladed vertical shaft rotor 600 engaged with the alternator 90. The six-bladed vertical shaft rotor 600 is useful in this situation: it is desirable to mechanically exert less than 10% of the pulsating force on the system. According to the embodiment shown, six vertically positioned vane units 81 are connected to a central ring 82. The central ring 82 is connected to a base 104, which base 104 rotates the poles 115 to turn the alternator 90. The vane units 81a-c in the upper part 83 of the rotor 600 are set at half the angle of the vane units 81d-f in the lower part 85. The offset vane configuration results in improved actuation and minimizes dynamic thrust from the vane unit 81 to the configuration 600. Thus, the rotor 600 may start to rotate in low speed wind, and when it rotates, there is a minimum of impetus through the device. The hollow, aerodynamically shaped rings 84 at the top and bottom of the rotor 600 serve as drag reducing ends for the blade units 81 and distribute the blade tip loads around the center ring 82. The hydrodynamically shaped torus used as the top and bottom rings 84 allows the rings to reduce and terminate the tip swirl induced lean of the vane cells. As is known, a torus is a rotating surface in the shape of a ring, which is created by rotating a circle about an axis coplanar with the circle. In addition, the structure and location of these rings 84 serve as structural elements for the rotor 600. As will be described below, a set of three aerodynamic adjusters 300a-c causes the rotor 600 to reduce its rotational speed in high winds.

While the six blade unit design provides a light weight and strong structural balance and it uses an aerodynamic regulator, other designs with other numbers of blade units may be used according to certain embodiments disclosed herein, depending on the specific conditions and requirements desired for the turbine.

Fig. 6 is a schematic side view of a six-bladed rotor 600. According to fig. 6 and as discussed with reference to fig. 5, the rotor 600 rotates about the central axis a. Furthermore, the vane unit 81 in the upper portion 83 of the rotor 600 is offset sixty degrees relative to the vane unit 81 in the lower portion 85 to facilitate turbine start-up and reduce dynamic thrust between the vane unit 81 and the rotor 600. Although the illustrated embodiment turns the vane unit by 60 degrees, any other angle may be used to facilitate turbine startup and reduce dynamic thrust. Also, in both the upper portion 83 and the lower portion 85, the respective blade units 81 are positioned 120 degrees apart from each other. Although the embodiment shown positions the blade units 120 degrees apart from each other, any other angle may be used to facilitate use of the turbine.

It is realized that in one embodiment, the shape of the vane elements 81 is the same as the shape of the airfoil 18. Therefore, the shape and size of the airfoil 18 shown in table 1 above is useful in designing the blade unit 81. Furthermore, as described above, for the airfoil 18, these vane elements 81 may have a blunt trailing edge. Of course, the shape of these blade units 81 is not limited to any particular shape, and may have other advantageous shapes.

Fig. 7 is a top view of a six-bladed vertical axis rotor 600. The center ring unit 82 is connected to the base 104 by a tube 103 in the aerodynamic adjuster 300. These tubes 103 traverse and engage the movable airfoils 105 and 106 in the adjuster 300. The aerodynamic adjuster 300 uses centrifugal force from the rotation of the rotor 600 to move the wings 105 and 106 in opposite directions to reduce the speed at which the rotor moves. By moving the wings 105 and 106 in opposite directions, they act as actuated brakes to reduce the rotational efficiency of the rotor 600.

Aerodynamic force regulator

Fig. 8 is a schematic plan view of the aerodynamic force adjuster 300 for slowing down the rotation of the rotor 600 in a strong wind. According to the embodiment shown in fig. 8, the adjuster wings 62 and 63 have different lengths from each other so that the base 104 is given a low speed closest to the centre of rotation of the connection point 61. Additional resistance reducing devices may be added to the distal end of the adjuster 300 (not shown). While the fairing remains stable, the adjuster wings 105 and 106 move in opposite directions to allow aerodynamic equilibrium to act on them. In some embodiments, the wind turbine may have a wind sensor, thus, energizing the aerodynamic regulator to adjust the RPM of the turbine as the wind speed increases above 25 miles per hour. However, as the wind becomes larger, for example 50 miles per hour, the wind sensor may activate a mechanical brake that may slow the speed of the rotor or stop the rotor altogether to prevent damage in high winds.

Fig. 9 is a schematic cross-sectional view of an embodiment of an aerodynamic adjuster assembly 300. As shown in fig. 10, an actuator is shown in which the small tube is connected to the weight by a pivot point, thus applying a force to the spring 75 through a sliding joint 77. As the adjuster assembly 300 rotates about the central axis of the rotor 600, centrifugal forces exerted on the weights cause them to move outwardly from the central axis. This movement causes the movable airfoils to actuate, so they begin to act as air brakes to slow the rotation of the rotor 600. The spring 75 is chosen such that the movable airfoil is actuated at the correct rotational speed. The sliding action caused by the internal weight activates a cam or threaded element on the tube that changes the angle of attack of the wing. In one embodiment of the actuator, the weight is a heavy tube within the outer tube, and it pushes against the spring until the centrifugal force overcomes the spring force. Opposing sensing threaded cams are attached to the load bearing tubes, which cams actuate the wings. Thus, the aerodynamic regulator regulates the rotor revolutions per minute ("RPM") to a relatively steady speed without the need for additional controls.

It will be appreciated by those skilled in the art that the wind turbine described above may be straightforwardly used or expanded in different ways. While the foregoing description refers to particular embodiments, the scope of the present invention is defined solely by the claims that follow and the elements described therein.

Claims (17)

1. A vertical axis wind turbine wing comprising:

a leading edge;

a trailing edge, wherein a distance between the leading edge and the trailing edge is defined as one;

a curved upper surface extending from the leading edge to the trailing edge;

a curved lower surface extending from the leading edge to the trailing edge; and

a centerline that runs from the leading edge to the trailing edge, wherein a maximum distance between the centerline and the upper surface is a thickness defined as 0.5, and wherein the airfoil is shaped to: having a thickness at a given distance from the leading edge to the trailing edge according to the following table:

distance between two adjacent plates Thickness of 0 0 0.005 0.07 0.01 0.11 0.05 0.24 0.1 0.34 0.35 0.5 0.60 0.39 0.80 0.22 1.0 0.0

2. The airfoil of claim 1, wherein the airfoil is further shaped to: having a thickness at a given distance from the leading edge according to the following table:

distance between two adjacent plates Thickness of 0.002 0.05 0.007 0.09 0.03 0.19 0.06 0.27 0.08 0.3 0.2 0.45 0.45 0.48 0.7 0.31 0.9 0.12

3. The airfoil of claim 1, wherein the airfoil is shaped to: having a thickness at a given distance from the leading edge according to the following table:

distance between two adjacent plates Thickness of 0 0.001 0.035078 0.002 0.049608 0.003 0.060757 0.004 0.070156 0.005 0.078436 0.006 0.085923 0.007 0.092807 0.008 0.099215 0.009 0.105233 0.01 0.11 0.02 0.156873 0.03 0.192129 0.04 0.221852 0.05 0.248038 0.051928 0.252774 0.06 0.271178 0.07 0.291407 0.08 0.309567 0.09 0.326335 0.1 0.34 0.15 0.408723 0.2 0.454353 0.25 0.482354 0.3 0.496254 0.35 0.5 0.4 0.495243 0.45 0.480917 0.5 0.457402 0.55 0.427095 0.6 0.39 0.65 0.353088 0.7 0.310766 0.75 0.26637 0.8 0.22 0.85 0.173868 0.9 0.127219 0.95 0.081241 0.986813 0.045298 1 0

4. The airfoil of claim 1, wherein the airfoil comprises a foam-filled composite material.

5. The wing of claim 1, wherein the wing comprises metal with a stringer.

6. A vertical axis wind turbine comprising:

a vertical shaft rotor, the vertical shaft rotor comprising:

a plurality of vertically arranged airfoils according to claim 1 wherein said airfoils are configured to rotate about a vertical axis.

7. The wind turbine of claim 6, wherein the plurality of airfoils are arranged vertically in groups as upper and lower airfoils.

8. The wind turbine of claim 7, wherein the plurality of upper airfoils comprises at least three airfoils.

9. The wind turbine of claim 7, wherein the plurality of lower airfoils comprises at least three airfoils.

10. The wind turbine of claim 7, wherein said plurality of upper airfoils are offset sixty degrees from said plurality of lower airfoils.

11. The wind turbine of claim 6, wherein the plurality of airfoils are connected to a central magnetic pole that rotates when the rotor rotates.

12. The wind turbine of claim 6, wherein the rotor comprises an air conditioner.

13. The wind turbine of claim 12, wherein the air regulator comprises two movable airfoils.

14. The wind turbine of claim 13, wherein the air regulator is configured to move the two movable airfoils.

15. The wind turbine of claim 14, wherein the movable airfoils move in opposite directions to reduce a rotational speed of the rotor.

16. The wind turbine of claim 6, wherein the plurality of airfoils are disposed with an angle of attack of 0-5 degrees.

17. The wind turbine of claim 6, wherein the plurality of airfoils are disposed with an angle of attack of 2 degrees.