Preferred wind turbines

Abstract

A HAT wind turbine (1) for generating electricity from wind comprises a tower (5), a nacelle (6), a generator, and a rotor (2), the rotor being rotatable about a rotor axis by wind, the rotor having a rotor solidity ratio SOL of up to 0.10. rotor and the rotor has a radius R (3), the rotor has at least four N blades (4) that reach a radial position of at least 0.90R, and the blades have a local chord c r (9) The distribution of the local chord c in the radial range r = 15%R to R r is one of less than 5.5% R, less than 5% R, less than 4.5% R, less than 4% R, less than 3% R, less than 2% R, and less than 1.5% R.

Description

[Technical Field]

[0001] The present invention relates to horizontal axis wind turbines (HATs), blades for HATs, methods for adapting existing HATs, methods for installing HATs, and methods for extracting useful power from HATs. [Background technology]

[0002] Wind energy is increasingly contributing to global energy production and has become one of the cheapest clean, renewable energy sources. This success has led to the installation of many wind turbines around the world. Especially in densely populated areas, the implementation of HATs faces the so-called "nimby" (i.e., "not in my backyard") problem. Many people support clean energy from HATs but do not want turbines in their neighborhoods. Some people associate HATs with obstacles. The obstacles experienced can also lead people to oppose wind energy projects, thereby delaying or even canceling their implementation. Environmental obstacles experienced from HATs typically include acoustic and visual obstacles, although other forms of environmental obstacles can also be perceived.

[0003] Visual obstructions can come in a variety of forms. Some people are annoyed by the large moving rotor blades, which can be visible from a distance of up to about 50 or even 100 times the rotor diameter from the turbine, depending on the size of the HAT. This visibility of the moving rotor is often experienced as disrupting the tranquility of the view.

[0004] Another form of visual obstruction can occur closer to the HAT. Depending on the position of the sun and the cloudiness of the sky, sunlight intensity can vary as a result of a moving cast shadow at the point where the HAT blades cast a repeating shadow pattern between the observer and the sun, which can occur up to a distance of about 12 rotor diameters. Cast shadows can also create obstructions for solar farms and crops that depend on the amount of sunlight received.

[0005] Yet another form of visual hazard can be caused by high intensity reflection of sunlight on the blade, this form of optical hazard has become less relevant in recent years as opalescent blade coatings that reduce reflection have been applied.

[0006] Acoustic interference is typically caused by rotating rotor blades. Known solutions to acoustic interference include the application of serrated blade trailing edges to reduce noise. In practice, this somewhat alleviates the acoustic interference, but usually not enough to eliminate the negative impression. Furthermore, the application of serrations increases cast shadow interference, which may be undesirable.

[0007] Most wind energy is harvested by HAT-type turbines, which typically contain one rotor and three blades, although multiple rotors are also possible. For example, a HAT may include a first rotor with a diameter of 113 m and a second coaxial rotor with a diameter of 40 m. Such a first rotor does not require blades with large chords near the rotor center because the second rotor, which typically rotates at a higher rpm, can efficiently harvest energy at the rotor center. Dual-rotor HATs are not common for several reasons. First, the two rotors operate at different rotational speeds, and therefore each rotor requires a mechanism to convert mechanical energy into electricity. Dual drivetrains increase cost and complexity. This complexity can increase downtime and subsequently reduce HAT yield. Second, the root bending moment of the large blades (the root is the portion of the blade closest to the hub) remains approximately the same compared to a single-rotor HAT. Because the root bending moments are approximately equal, the pitch bearings are approximately equal. To induce large bending moments, thick blade roots are preferably used. Thus, although the large blades may have a reduced chord, the total blade length and thickness, and therefore the amount of composite required, are generally similar to those of a turbine without a second rotor. Third, the typically thick blade roots of the large rotor within the range of the second, smaller rotor, have a somewhat cylindrical shape and generate large aerodynamic drag, thus reducing the yield of the large rotor. This drag, in turn, reduces the wind to the smaller rotor, thereby also reducing the yield of the smaller rotor. Furthermore, non-uniform air speeds within the small rotor area induced by the large rotor's blade roots cause additional noise, and the relative position of the small rotor's blades with respect to the large blade roots determines noise reflections, leading to more non-uniform noise levels.

[0008] The efficiency of a HAT can be expressed as yield per cost unit. It is undesirable to reduce HAT failure at the expense of HAT efficiency. Factors to take into account when expressing HAT efficiency include the transportation and installation of typically large and heavy HAT components, which already cause problems and should not be exacerbated. Summary of the Invention

[0009] The present disclosure aims to provide a horizontal axis turbine type wind turbine (hereinafter referred to as a "HAT" or "HAT wind turbine") that reduces one or more of the various impairment aspects described throughout this disclosure while maintaining or even improving the efficiency of state-of-the-art HATs.

[0010] Wind power is one of the most important renewable energy sources enabling the global energy transition. Producing large amounts of energy from wind, accounting for a significant portion of global energy consumption, requires large wind turbines with rotor diameters of 100 meters or more, and for offshore wind energy, such large turbines may be considered the only option. Unfortunately, wind turbines of this size also cause the most damage. In short, it would be advantageous if wind turbines, especially those with diameters of 100 meters or more, were less prone to damage. Experts in the art only consider two or three blades for horizontal axis wind turbines of this size. Therefore, quite different from the conventional adoption of HATs with three and sometimes two blades having relatively large chords, the present disclosure is a groundbreaking idea that favors the application of smaller chord blades, and potentially more blades, to address the following sources of damage: (i) cast shadows, (ii) disturbance of tranquil views, (iii) reduced solar farm or crop yields, (iv) average sound pressure, (v) audio amplitude modulation, (vi) inaudible sounds, and / or (vii) bird accidents. Additionally, this may simplify transportation and installation of the blades, leading to an improved yield to cost ratio for the wind turbine.

[0011] According to one aspect of the present disclosure, a HAT for generating power from wind is proposed. The HAT may include a tower. The HAT may further include a nacelle. The HAT may further include a generator. The HAT may further include a rotor. The rotor may be rotatable about a rotor axis by wind. The rotor may have a rotor solidity SOL of up to 0.10. rotor The rotor may have a radius R and a diameter D. The diameter D may be 100 m or greater. The rotor may include N blades, where N may be at least 4. The rotor may include a maximum chord of the blades, which may be less than 12%R, or less than 11%R, or less than 10%R, or less than 9%R, or less than 8%R.

[0012] According to one aspect of the present disclosure, a HAT for generating power from wind is proposed. The HAT may include a tower. The HAT may further include a nacelle. The HAT may further include a generator. The HAT may further include a rotor. The rotor may be rotatable about a rotor axis by wind. The rotor may have a rotor solidity SOL of up to 0.10. rotor The rotor may have a radius R. The rotor may include N blades extending to a radial position of at least 0.90R, where N may be at least 4. The blades may have a local chord c r It may have a distribution of relative radial position r, and the local chord c in the radial range of r = 15% R to R r may be less than 5.5%R.

[0013] According to one aspect of the present disclosure, a HAT for generating power from wind is proposed. The HAT may include a tower. The HAT may further include a nacelle. The HAT may further include a generator. The HAT may further include a rotor. The rotor may be rotatable about a rotor axis by wind. The rotor may have a rotor solidity SOL of up to 0.10. rotorThe rotor may have a radius R. The rotor may include N blades extending to a radial position of at least 0.90R, where N may be at least 2. The blades may have a local chord c r It may have a distribution of relative radial position r, and the local chord c in the radial range of r = 15% R to R r may be less than 9%R. The rotor has an average mean radial solidity "avgsol. 25R ” and the average radial rigidity over the radial range of 0.65R~0.85R “avgsol. 75R " and may further include avgsol. 25R / avgsol. 75R may be less than 2.00.

[0014] The rotor has an average radial solidity "avgsol. over the radial range of 0.15R to 0.35R. 25R ” and the average radial rigidity over the radial range of 0.65R~0.85R “avgsol. 75R " may further include ".

[0015] In one embodiment, avgsol. 25R / avgsol. 75R may be less than 2.00.

[0016] In one embodiment, avgsol. 25R / avgsol. 75R may be less than 1.75.

[0017] In one embodiment, avgsol. 25R / avgsol. 75R may be less than 1.50.

[0018] In one embodiment, avgsol. 25R / avgsol. 75R may be less than 1.25.

[0019] In one embodiment, avgsol. 25R / avgsol. 75R may be less than 1.

[0020] In one embodiment, avgsol. 25R / avgsol. 75R may be less than 0.9.

[0021] In one embodiment, avgsol. 25R / avgsol. 75R may be less than 0.75.

[0022] In one embodiment, avgsol. 25R / avgsol. 75R may be less than 0.5.

[0023] In one embodiment, avgsol. 25R / avgsol. 75R may be less than 0.25.

[0024] The rotor has an average radial solidity "avgsol. 35R " may further be included.

[0025] In one embodiment, avgsol. 35R / avgsol. 75R may be less than 1.75.

[0026] In one embodiment, avgsol. 35R / avgsol. 75R may be less than 1.50.

[0027] In one embodiment, avgsol. 35R / avgsol. 75R may be less than 1.25.

[0028] In one embodiment, avgsol. 35R / avgsol. 75R may be less than 1.

[0029] In one embodiment, avgsol. 35R / avgsol. 75R may be 0.9 or less.

[0030] In one embodiment, avgsol. 35R / avgsol. 75R may be less than 0.75.

[0031] In one embodiment, avgsol. 35R / avgsol. 75R may be less than 0.5.

[0032] In one embodiment, avgsol. 35R / avgsol. 75R may be less than 0.25.

[0033] The rotor has a radial solidity sol at a radial position of 0.25R. 25R and the radial rigidity sol at the radial position 0.75R. 75R The ratio between their radial stiffnesses may be sol. 25R / sol. 75R It can be expressed as:

[0034] In one exemplary embodiment, sol. 25R / sol. 75R may be less than 2.00.

[0035] In one exemplary embodiment, sol. 25R / sol. 75R may be less than 1.75.

[0036] In one exemplary embodiment, sol. 25R / sol. 75R may be less than 1.50.

[0037] In one exemplary embodiment, sol. 25R / sol. 75R may be less than 1.25.

[0038] In one exemplary embodiment, sol. 25R / sol. 75R may be less than 1.00.

[0039] In one exemplary embodiment, sol. 25R / sol. 75R may be less than 0.90.

[0040] In one exemplary embodiment, sol. 25R / sol. 75R may be less than 0.75.

[0041] In one exemplary embodiment, sol. 25R / sol. 75R may be less than 0.50.

[0042] In one exemplary embodiment, sol.25R / sol. 75R may be less than 0.25.

[0043] In one embodiment, c r may be less than 8%R for r=15%R to R.

[0044] In one embodiment, c r may be less than 7%R for r=15%R to R.

[0045] In one embodiment, c r may be less than 5.5%R for r=15%R to R.

[0046] In one embodiment, c r may be less than 5%R for r=15%R to R.

[0047] In one embodiment, c r may be less than 4.5%R for r=15%R to R.

[0048] In one embodiment, c rmay be less than 4%R for r=15%R to R.

[0049] In one embodiment, c r may be less than 3%R for r=15%R to R.

[0050] In one embodiment, c r may be less than 2%R for r=15%R to R.

[0051] In one embodiment, c r may be less than 1.5%R for r=15%R to R.

[0052] In one embodiment, c r For r=15%R~R, 5.5%R-2.5 / 85 * It may be less than (r-15%R).

[0053] In one embodiment, c r For r=15%R~R, 5%R-2 / 85 * It may be less than (r-15%R).

[0054] In one embodiment, c r For r=15%R~R, 4.5%R-1.5 / 85 * It may be less than (r-15%R).

[0055] In one embodiment, c r For r=15%R~R, 4%R-1 / 85 * It may be less than (r-15%R).

[0056] In one embodiment, c r For r=15%R~R, 3.5%R-0.5 / 85 * It may be less than (r-15%R).

[0057] In one embodiment, c r For r=15%R~R, 5.5%R-3.5 / 85 *It may be less than (r-15%R).

[0058] In one embodiment, c r For r=15%R~R, 5%R-3 / 85 * It may be less than (r-15%R).

[0059] In one embodiment, c r For r=15%R~R, 4.5%R-2.5 / 85 * It may be less than (r-15%R).

[0060] In one embodiment, c r For r=15%R~R, 4%R-2 / 85 * It may be less than (r-15%R).

[0061] In one embodiment, c r For r=15%R~R, 3.5%R-1.5 / 85 * It may be less than (r-15%R).

[0062] In one embodiment, c r For r=15%R~R, 3%R-1 / 85 * It may be less than (r-15%R).

[0063] In one embodiment, c r For r=15%R~R, 2.5%R-0.5 / 85 * It may be less than (r-15%R).

[0064] In one embodiment, c r For r=15%R~R, 5.5%R-4.0 / 85 * It may be less than (r-15%R).

[0065] In one embodiment, c r For r=15%R~R, 5%R-3.5 / 85 * It may be less than (r-15%R).

[0066] In one embodiment, c r For r=15%R~R, 4.5%R-3.0 / 85 * It may be less than (r-15%R).

[0067] In one embodiment, c r For r=15%R~R, 4%R-2.5 / 85 * It may be less than (r-15%R).

[0068] In one embodiment, c r For r=15%R~R, 3.5%R-2.0 / 85 * It may be less than (r-15%R).

[0069] In one embodiment, c r For r=15%R~R, 3%R-1.5 / 85 * It may be less than (r-15%R).

[0070] In one embodiment, a rotor may include blades with local chords that may be less than a particular limit line for r = 15%R to R. In such cases, the chord may be greater than the predetermined limit line over a range of up to 5%R. This may be useful, for example, to compensate for blade connections, etc., that may result in an increase in chord over a radial range of less than 5%.

[0071] In one embodiment, the HAT may include at least three blades that reach a radial position r of at least one of 0.70R and 0.90R.

[0072] In one embodiment, the HAT may include at least four blades that reach a radial position r of at least one of 0.70R and 0.90R.

[0073] In one embodiment, the HAT may include at least five blades that reach a radial position r of at least one of 0.70R and 0.90R.

[0074] In one embodiment, the HAT may include at least seven blades that reach a radial position r of at least one of 0.70R and 0.90R.

[0075] In one embodiment, the HAT may include at least 11 blades that reach a radial position r of at least one of 0.70R and 0.90R.

[0076] In one embodiment, the number N of blades that reach a radial position r of at least one of 0.70R and 0.90R may be up to seven.

[0077] In one embodiment, the number N of blades that reach a radial position r of at least one of 0.70R and 0.90R may be up to 11.

[0078] In one embodiment, the number N of blades that reach a radial position r of at least one of 0.70R and 0.90R may be up to 17.

[0079] In one embodiment, the number N of blades that reach a radial position r of at least one of 0.70R and 0.90R may be up to 43.

[0080] In one exemplary embodiment, the number N of blades at one of the radial positions r of 0.70R and 0.90R may be equal to a prime number.

[0081] In one exemplary embodiment, N may be 4. In another exemplary embodiment, N may be 5. In another exemplary embodiment, N may be 6. In another exemplary embodiment, N may be 7. In one exemplary embodiment, N may be 11.

[0082] In one embodiment, the diameter D may be at least 5 m.

[0083] In one embodiment, the diameter D may be at least 10 m.

[0084] In one embodiment, the diameter D may be at least 20 m.

[0085] In one embodiment, the diameter D may be at least 40 m.

[0086] In one embodiment, the diameter D may be at least 70 m.

[0087] In one embodiment, the diameter D may be at least 100 m.

[0088] In one embodiment, the diameter D may be at least 140 m.

[0089] In one embodiment, the diameter D may be at least 200 m.

[0090] In one embodiment, the diameter D may be less than 40m and at least 3m.

[0091] In one embodiment, the diameter D may be less than 40m and at least 5m.

[0092] In one embodiment, the diameter D may be less than 40 m and at least 10 m.

[0093] In one embodiment, the diameter D may be less than 40m and at least 25m.

[0094] In one embodiment, the rotor has a C P The axial length may be designed to have

[0095] In one embodiment, the rotor has a C P The axial length may be designed to have

[0096] In one embodiment, the rotor has a C PE The axial length may be designed to have

[0097] In one embodiment, the rotor has a C PE The axial length may be designed to have

[0098] In one embodiment, the rotor has a C PE The axial length may be designed to have

[0099] In one embodiment, the rotor has a C PE The axial length may be designed to have

[0100] C in some embodiments P Values ​​are often greater than 0.45 C P The cost-to-yield ratio may be higher than that of a large, state-of-the-art HAT. This may be explained by the small chords used by some embodiments, which may result in less energy being captured near the rotor center. The cost-to-yield ratio may be more relevant and higher than that of a large, state-of-the-art HAT.

[0101] In one embodiment, the rotor has a maximum solidity SOL of 0.07. rotor It may be configured so that:

[0102] In one embodiment, the rotor has a maximum solidity SOL of 0.05. rotor It may be configured so that:

[0103] In one embodiment, the rotor has a maximum solidity SOL of 0.04. rotor It may be configured so that:

[0104] In one embodiment, the rotor has a maximum solidity SOL of 0.035. rotor It may be configured so that:

[0105] In one embodiment, the rotor has a maximum solidity SOL of 0.03. rotor It may be configured so that:

[0106] In one embodiment, avgsol. 25Rmay be less than 0.06.

[0107] In one embodiment, avgsol. 25R may be less than 0.05.

[0108] In one embodiment, avgsol. 25R may be less than 0.04.

[0109] In one embodiment, avgsol. 25R may be less than 0.03.

[0110] In one embodiment, the rotor has a design tip speed ratio λ design =ωR / U, and λ design is less than 9.

[0111] In one embodiment, the rotor has a λ of less than 8 design It may be configured as follows.

[0112] In one embodiment, the rotor has a λ of less than 7 design It may be configured as follows.

[0113] In one embodiment, the rotor has a λ of less than 6 design It may be configured as follows.

[0114] In one embodiment, the rotor has a λ of less than 5 design It may be configured as follows.

[0115] In one embodiment, the rotor may include a first blade and a second blade, and the first blade and the second blade may have a tangential connection at a radial location R3.

[0116] In one embodiment, one of the following may apply: R3>0.20R, R3>0.30R, R3>0.40R, or R3>0.45R.

[0117] In one embodiment, one of the following may be applied: R3 < 0.80R, R3 < 0.70R, R3 < 0.60R, or R3 < 0.50R.

[0118] In one embodiment, one of the following may be applied: 0.20R < R3 < 0.80R, 0.30R < R3 < 0.70R, or 0.40R < R3 < 0.60R.

[0119] In one embodiment, the HAT may further include a stay and a stay holder. The blade, stay, and stay holder may be connected at a radial position between 0.25R and 0.65R. The stay holder may be pivotally connected to the blade at the joint such that the blade can be pitch-adjusted around the joint for at least 30 degrees. Alternatively, the blade may be pitch-adjusted around the joint for at least 60 degrees. Alternatively, the blade may be pitch-adjusted around the joint for at least 90 degrees.

[0120] In one embodiment, the truss structure at the center of the rotor may connect the blade to the hub. The truss structure may include blade joints and hub joints that can be connected by one of the compression members, which are two compression members, and the stay. The pitch-adjustable blade may be connected to a pitch bearing at the blade joint. The blade joint may be connected to the blade joints of adjacent blades by a compression member or a stay.

[0121] In one embodiment, the rotor blade may not have a structural support portion outside the radial position of 70%R. For example, there may be no structural support portion from the compression member or the stay to the blade beyond 70%R. The support portion in this range has been found to be disadvantageous as it reduces the aerodynamic performance.

[0122] In one embodiment, the compression members and / or stays may have an aerodynamic shape that enables the compression members and / or stays to generate aerodynamic lift that contributes to rotor torque when the HAT is in use.

[0123] In one embodiment, the blades may be fixed to the pitch bearings.

[0124] In one embodiment, the pitch bearing may be located at a radial position that is greater than 0.25R and less than 0.6R.

[0125] In one embodiment, the pitch bearing may be located at a radial position that is greater than 0.3R and less than 0.6R.

[0126] In one embodiment, the pitch bearing may be located at a radial position that is greater than 0.35R and less than 0.6R.

[0127] In one embodiment, the pitch bearing may be located at a radial position that is greater than 0.4R and less than 0.6R.

[0128] In one embodiment, the pitch bearing may be located at a radial position that is greater than 0.45R and less than 0.6R.

[0129] In one embodiment, the HAT may include a first blade and a second blade. The first blade may be part of a first rotor and may reach a radial position R. The second blade may be part of a second rotor and may reach a radial position R2.

[0130] In one embodiment, one of the following may apply: R2<0.70R, R2<0.60R, or R2<0.55R.

[0131] In one embodiment, one of the following may apply: R2>0.25R, R2>0.30R, R2>0.35R, or R2>0.40R.

[0132] In one embodiment, one of the following may be applied: 0.25R < R2 < 0.70R, 0.30R < R2 < 0.60R, 0.35R < R2 < 0.55R, or 0.40R < R2 < 0.55R.

[0133] In one embodiment, the second rotor having the second blade may not directly generate energy by not being connected to the generator and may be designed to rotate freely.

[0134] In one embodiment, the second rotor may be further designed to have an axial force coefficient C D,ax when in use. When rotating freely, one of the following: C D,ax > 0.6, C D,ax > 1.0, C D,ax > 1.2, C D,ax > 1.5, or C D,ax < 2.2 may be applied to the second rotor.

[0135] In one embodiment, the HAT has a blade including a drawn airfoil profile having a length of at least one of at least 5 %R, at least 60 %R, at least 70 %R, and at least 80 %R.

[0136] In one embodiment, the drawn airfoil may have twist, may have a vortex generator, and may have a Gurney flap.

[0137] In an exemplary embodiment, a rotor having blades extending up to 0.90R may have variable speed stall control. The small chord and small aspect ratio reduce the rotor stiffness, and as a result, the survival wind speed loads are reduced. This advantage can be utilized to control the rotor using variable speed stall to avoid overloading and / or overfeeding, and further, the additional advantage of not requiring pitch control results in savings in the pitch mechanism and its maintenance.

[0138] In one embodiment, D may be greater than 1 m and less than 50 m. The HAT may include an aft vane surface for aligning the rotor with the wind. A portion of the aft vane surface may be hinged. Hinging the portion means that the portion can pivot relative to the nacelle in response to wind forces on that portion. The aft vane surface may be axially spaced apart by πR. 2 Alternatively, the rear vane may be larger than πR 2 Alternatively, the rear vane may be greater than πR 2 Alternatively, the rear vane may be larger than 1 / 2D. 2 Alternatively, the rear vane may be 3 / 4D 2 Alternatively, the trailing vane may be larger than D 2 Alternatively, the rear vane may be larger than 1 1 / 2D. 2 It may be larger than

[0139] In one embodiment, the HAT may be a land-based turbine.

[0140] In one embodiment, the HAT may be an offshore turbine.

[0141] In one embodiment, the HATs may be parallel-connected.

[0142] In one embodiment, the HAT may be standalone.

[0143] In one embodiment, the HAT may have exactly one rotor.

[0144] In one embodiment, the HAT may have exactly one largest rotor of radius R and exactly one second coaxial rotor of radius R2.

[0145] In one embodiment, the HAT may have two rotors that are coaxial and rotate in the same direction.

[0146] In one embodiment, the rotor may be downwind relative to the tower. This may be advantageous as it may save on active yaw mechanics. Another possible advantage is that in a downwind configuration, the thin blades with low chord values ​​according to one embodiment have more room to flex, and in this configuration, loads may cause the blades to flex away from the tower instead of flexing towards the tower as in an upwind configuration.

[0147] In one embodiment, the rotor may be upwind relative to the tower.

[0148] In one embodiment, the rotor may be supported by towers on both the windward and leeward sides.

[0149] In one embodiment, the HAT may have an upwind rotor and a downwind rotor.

[0150] In one embodiment, the generator may be of the direct drive type.

[0151] In one embodiment, the generator may be of the gear type.

[0152] In one embodiment, the generator may use superconductivity.

[0153] In one embodiment, the rotor may drive a fluid conduction.

[0154] In one embodiment, mechanical power may be first converted to fluid power and then converted to electrical power.

[0155] In one embodiment, the rotor comprises a ring-like structure extending radially by less than 20%R.

[0156] In another embodiment, the rotor may not include a ring-like structure.

[0157] In one embodiment, the rotor may include an airfoil having a relative thickness t / c of ​​30% or greater.

[0158] In one embodiment, the rotor may have a cambered airfoil.

[0159] In one embodiment, vortex generators may be attached to the rotor.

[0160] In one embodiment, the rotor has a design lift coefficient c of 1.5 or greater. l,design The airfoil may include an airfoil having

[0161] In one embodiment, the rotor may include blade sections having a weight percentage of carbon fiber of 10% or greater.

[0162] In one embodiment, the rotor may be of the fast runner type, with a design tip speed ratio λ design and λ design may be greater than four.

[0163] In one embodiment, the rotor may be of the fast runner type, with a design tip speed ratio λ design and λ design may be greater than 5.

[0164] In one embodiment, the rotor may be of the fast runner type, with a design tip speed ratio λ design and λ design may be greater than 6.

[0165] In one embodiment, the composite string N r c r may be less than 16.5%R.

[0166] In one embodiment, N r c r may be less than 15%R for r=15%R to R.

[0167] In one embodiment, N r c r may be less than 13.5%R for r=15%R to R.

[0168] In one embodiment, N r c r may be less than 12.0%R for r=15%R to R.

[0169] In one embodiment, N r c r may be less than 10.5%R for r=15%R to R.

[0170] In one embodiment, N r c r may be less than 9.0%R for r=15%R to R.

[0171] In one embodiment, N r c r may be less than 7.5%R for r=15%R to R.

[0172] In one embodiment, N r c r may be less than 6.0%R for r=15%R to R.

[0173] In one embodiment, N r c r For r=15%R~R, 16.5%R-7.5 / 85 * It may be less than (r-15%R).

[0174] In one embodiment, N r c r For r=15%R~R, 15%R-6.0 / 85 * It may be less than (r-15%R).

[0175] In one embodiment, N r c r For r=15%R~R, 13.5%R-4.5 / 85 * It may be less than (r-15%R).

[0176] In one embodiment, N r c rFor r=15%R~R, 12%R-3.0 / 85 * It may be less than (r-15%R).

[0177] In one embodiment, N r c r For r=15%R~R, 16.5%R-10.5 / 85 * It may be less than (r-15%R).

[0178] In one embodiment, N r c r For r=15%R~R, 15%R-9.0 / 85 * It may be less than (r-15%R).

[0179] In one embodiment, N r c r For r=15%R~R, 13.5%R-7.5 / 85 * It may be less than (r-15%R).

[0180] In one embodiment, N r c r For r=15%R~R, 12.0%R-6.0 / 85 * It may be less than (r-15%R).

[0181] In one embodiment, N r c r For r=15%R~R, 10.5%R-4.5 / 85 * It may be less than (r-15%R).

[0182] In one embodiment, N r c r For r=15%R~R, 9.0%R-3.0 / 85 * It may be less than (r-15%R).

[0183] In one embodiment, N r c r For r=15%R~R, 7.5%R-1.5 / 85 * It may be less than (r-15%R).

[0184] In one embodiment, N r c r For r=15%R~R, 16.5%R-12.0 / 85 * It may be less than (r-15%R).

[0185] In one embodiment, N r c r For r=15%R~R, 15%R-10.5 / 85 * It may be less than (r-15%R).

[0186] In one embodiment, N r c r For r=15%R~R, 13.5%R-9.0 / 85 * It may be less than (r-15%R).

[0187] In one embodiment, N r c r For r=15%R~R, 12%R-7.5 / 85 * It may be less than (r-15%R).

[0188] In one embodiment, N r c r For r=15%R~R, 10.5%R-6.0 / 85 * It may be less than (r-15%R).

[0189] In one embodiment, N r c r For r=15%R~R, 9.0%R-4.5 / 85 * It may be less than (r-15%R).

[0190] In one embodiment, N r c r For r=15%R~R, 7.5%R-3.0 / 85 * It may be less than (r-15%R).

[0191] In some embodiments, the rotor may have a composite chord that may be below a particular limit line for r = 15%R to R. In such cases, the composite chord may be greater than the predetermined limit line over a range of up to 5%R. This may serve to compensate, for example, for blade connections that may result in an increase in composite chord over a radial range of less than 5%.

[0192] According to one aspect of the present disclosure, a blade may be proposed for use in a rotor of a HAT for extracting useful power from wind. The blade may be rotatable about a shaft of the HAT by wind. The blade has a local chord c from L=0 at the blade root to L=100% at the blade tip. L It may have a distribution of blade length positions l, and for local chord l=15%L to L, L may be less than 5.5%L. The local chord sol at the blade length position 0.25L 0.25L and the string sol at blade length position 0.75L 0.75L The ratio of sol 0.25L / sol 0.75L and may be less than 2.00.

[0193] In one embodiment, for l=15%L to L, c L may be less than 5%L.

[0194] In one embodiment, for l=15%L to L, c L may be less than 4.5%L.

[0195] In one embodiment, for l=15%L to L, c L may be less than 4%L.

[0196] In one embodiment, for l=15%L to L, c L may be less than 3%L.

[0197] In one embodiment, for l=15%L to L, c L may be less than 2%L.

[0198] In one embodiment, for l=15%L to L, c L may be less than 1.5%L.

[0199] In one embodiment, for l=15%L to L, c L is 5.5%L-2.5 / 85 * (1-15%L) may be less.

[0200] In one embodiment, for l=15%L to L, c L is 5%L-2 / 85 * (1-15%L) may be less.

[0201] In one embodiment, for l=15%L to L, c L is 4.5%L-1.5 / 85 * (1-15%L) may be less.

[0202] In one embodiment, for l=15%L to L, c L is 4%L-1.5 / 85 * (1-15%L) may be less.

[0203] In one embodiment, for l=15%L to L, c L is 3.5%L-0.5 / 85 * (1-15%L) may be less.

[0204] In one embodiment, for l=15%L to L, c L is 5.5%L-3.5 / 85 * (1-15%L) may be less.

[0205] In one embodiment, for l=15%L to L, c L is 5%L-3 / 85 * (1-15%L) may be less.

[0206] In one embodiment, for l=15%L to L, c L is 4.5%L-2.5 / 85 *(1-15%L) may be less.

[0207] In one embodiment, for l=15%L to L, c L is 4%L-2 / 85 * (1-15%L) may be less.

[0208] In one embodiment, for l=15%L to L, c L is 3.5%-1.5 / 85 * (1-15%L) may be less.

[0209] In one embodiment, for l=15%L to L, c L is 3%L-1 / 85 * (1-15%L) may be less.

[0210] In one embodiment, for l=15%L to L, c L is 2.5%L-0.5 / 85 * (1-15%L) may be less.

[0211] In one embodiment, for l=15%L to L, c L may be less than 2%L.

[0212] In one embodiment, for l=15%L to L, c L is 5.5%L-4.0 / 85 * (1-15%L) may be less.

[0213] In one embodiment, for l=15%L to L, c L may be less than 5%L-3.5 / 85*(l-15%L).

[0214] In one embodiment, for l=15%L to L, c L is 4.5%L-3.0 / 85 * (1-15%L) may be less.

[0215] In one embodiment, for l=15%L to L, c L is 4%L-2.5 / 85* (1-15%L) may be less.

[0216] In one embodiment, for l=15%L to L, c L is 3.5%L-2.0 / 85 * (1-15%L) may be less.

[0217] In one embodiment, for l=15%L to L, c L is 3%L-1.5 / 85 * (1-15%L) may be less.

[0218] In one embodiment, for l=15%L to L, c L may be less than 1.5%L.

[0219] In one exemplary embodiment, sol 0.25L / sol 0.75L may be less than 1.75.

[0220] In one exemplary embodiment, sol 0.25L / sol 0.75L may be less than 1.50.

[0221] In one exemplary embodiment, sol 0.25L / sol 0.75L may be less than 1.25.

[0222] In one exemplary embodiment, sol 0.25L / sol 0.75L may be less than 1.00.

[0223] In one exemplary embodiment, sol 0.25L / sol 0.75L may be less than 0.90.

[0224] In one embodiment, a blade according to the present invention may be made from a single piece having a length of at least one of 40 m, 60 m, 80 m, 100 m. The thinness of such a blade may be advantageous because a shorter chord may be easier to transport and the thinness may make the blade more flexible.

[0225] According to one aspect of the present disclosure, a method for adapting an existing HAT may be proposed. The method may include removing a rotor from the existing HAT. The method may further include installing a new rotor such that the HAT has one or more of the above-described characteristics.

[0226] According to one aspect of the present disclosure, a method for extracting useful power from wind may be proposed using a HAT having one or more of the above-described features. The method may include rotating blades of the HAT about a shaft with the wind. The method may further include converting torque from a rotor of the HAT into electrical energy using a generator of the HAT.

[0227] Hereinafter, embodiments of the present disclosure may be described by way of example only. [Brief explanation of the drawings]

[0228] Some embodiments are illustrated in the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts. [Figure 1] An onshore upwind HAT with seven blades is shown. [Figure 2] An offshore upwind HAT with five blades is shown. [Figure 3] An onshore upwind HAT with seven blades and seven shorter blades is shown. [Figure 4] 1 illustrates the local chord distribution and limits of one embodiment. [Figure 5] 1 illustrates the local chord distribution and limits of one embodiment. [Figure 6] A land-based HAT with seven blades and a second rotor with three blades is shown. [Figure 7] Shown is a land-based HAT with seven blades and stays. [Figure 8] Shown is a stay holder that allows blade pitch adjustment. [Figure 9] An offshore HAT with a three-bladed downwind rotor with stays is shown. [Figure 10] An offshore HAT is shown with a large downwind rotor and a small upwind rotor. [Figure 11] A small land-based 11-blade rotor with large trailing vanes is shown. [Figure 12] 1 illustrates the shadow effect of the prior art and one embodiment. [Figure 13] The AM noise caused by blade passing is shown for different numbers of blades. [Figure 14] 1 shows a pultruded twisted airfoil section with integrated structural elements. [Figure 15] 1 shows a pultruded airfoil section with cuts to reduce torsional stiffness. [Figure 16] 1 shows an airfoil with transparent indentations. [Figure 17] 1 shows an airfoil with a pointed trailing edge. [Figure 18] 1 shows an airfoil with vortex generators. [Figure 19] 1 shows an improved vortex generator pair. [Figure 20] 1 illustrates the local chord distribution and limits of one embodiment. [Figure 21] 1 shows a tiltable HAT with five pultruded twist blades. [Figure 22] 1 illustrates the composite strings and limitations of one embodiment. [Figure 23] 1 illustrates the composite strings and limitations of one embodiment. [Figure 24] 1 illustrates the composite strings and limitations of one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0229] It will be readily understood that the components of the embodiments generally described herein and / or illustrated in the accompanying drawings may be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of various embodiments, as illustrated in the drawings, is not intended to limit the scope of the disclosure, but is merely representative of various embodiments.

[0230] The drawings and described embodiments are intended for illustrative purposes only and do not limit the scope of protection as claimed. The drawings are not drawn to scale unless otherwise specified.

[0231] The scope of the invention is indicated by the appended claims, rather than this detailed description, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced by them.

[0232] References to features, advantages, or similar language throughout this specification do not imply that all features and advantages that may be realized in the present invention are to be a single example of the present invention. Rather, language referring to features and advantages may be understood to mean that a particular feature, advantage, or characteristic that is described in connection with one embodiment may be included in at least one embodiment of the present invention. Thus, references to features, advantages, and similar language throughout this specification may, but need not, refer to the same example.

[0233] Furthermore, the described features, advantages, and characteristics of the invention may be combined in any suitable manner in an embodiment. Those skilled in the art will understand, upon reviewing the description herein, that the invention can be practiced without one or more specific features or advantages of a particular embodiment. In other instances, they will understand that additional features and advantages observed in a particular embodiment may not be present in all embodiments of the invention. References throughout this specification to "one embodiment," "one embodiment," or similar language mean that a particular feature, structure, or characteristic described in connection with the illustrated embodiment is included in at least one embodiment of the invention. Thus, references throughout this specification to the phrase "in one embodiment," "in one embodiment," or similar language may, but do not necessarily, all refer to the same embodiment.

[0234] Terminology used The following terms are used throughout this disclosure.

[0235] The inventors define a HAT wind turbine "HAT" in this disclosure as a horizontal axis turbine type wind turbine having a maximum rotor of radius R, which is designed to extract useful energy from the wind, and which is non-airborne and has a fixed foundation.

[0236] Airborne devices are excluded due to at least one of the following reasons: shadow, noise, and bird obstruction mechanisms are not comparable to those of HATs; overall aerodynamic and / or structural optimization is not comparable.

[0237] Devices without fixed foundations are excluded for at least one of the following reasons: Devices without fixed foundations and therefore mobile have different optimizations. For example, the structure does not need to withstand high safety limit wind speeds of over 40 m / s, and the device should be easy to install and disassemble. Mobile devices have comparable failure characteristics and can be moved in the event of a failure, so they do not cause permanent failure in the same location. Mobile devices may be constructed with less durability and may not be intended for permanent power generation, but instead for occasional power delivery. Finally, mobile devices may be designed for easy transport and transportation. Mobile devices may be toy-like products that briefly drive LEDs for decorative purposes and cannot be compared to devices intended for bulk power generation. Note that floating offshore wind turbines and horizontal axis wind turbines installed on ships are considered to have fixed foundations. In one embodiment, the HAT is intended for large-volume energy generation in a fixed location and should be able to withstand wind speeds of one of 40 m / s, 60 m / s, 72 m / s, and 80 m / s.

[0238] The definition of a HAT may be further limited to one that does not include a ring-like structure that is coaxial with the rotor and extends radially to a position greater than 20%R, 30%R, 50%R, or 70%R. Such ring-like structures are known and may be disadvantageous. Three types of ring-like structures may exist: ring-like structures with a primarily structural function, a wind-concentrator rotor, and a direct-drive generator. Also, ring-like structures that are a combination of one or more of the three types are disadvantageous and excluded.

[0239] Ring-like structures that have a primarily structural function and extend to radial positions greater than 20%R, 30%R, 40%R, 50%R, or 70%R may be excluded for one of the following reasons: While ring-like structures connecting different blades are known, the arc-shaped connections of the ring-like structures between blades may be inefficient because they cannot efficiently handle tension and / or compression forces between the blades, and a straight connection would be more cost-effective. While ring-like structures with blades connected to a ring-like structure and no direct connection from the blade root to the hub along the blade length are known, this structure adds material and cost to the ring-like structure and can make the rotor inefficient because the bending moment at the blade root is completely captured by the torsion of the ring-like structure. Therefore, in one embodiment, every blade that reaches a radial position of 0.90R is directly connected to the hub by a straight structure along the blade length.

[0240] A wind-concentrator rotor designed to increase or decrease air speed within a wind concentrator ring, which may extend to a radial position greater than 20%R, 30%R, 40%R, 50%R, or 70%R, may be excluded for at least one of the following reasons: A wind-concentrator rotor has different aerodynamic and structural optimizations. The wind concentrator ring may be connected to four or more blades to form multiple load-bearing (movable) supports for the ring-shaped wind concentrator; the rationale for four or more blades does not make sense without the wind concentrator ring. A wind concentrator rotor may have four or more blades to reduce the intensity of circulation per blade and thereby reduce adverse aerodynamic interactions between the blade tips and the wind concentrator. Wind turbines with wind concentrator rings typically have a low yield-to-cost ratio. Large wind concentrators attract loads, especially under safe wind speed conditions. Wind concentrators can cause a lot of cast shadows, which can be expensive.

[0241] Devices with direct-drive generators extending radially beyond 20%, 30%, 40%, or 50% R may have a direct structural connection between the blades and the generator, rather than through a hub. This may be an argument for using a larger number of blades, providing more structural support for the generator and better load distribution and reduced load per support. However, direct connections between the generator and blades at radial locations of at least 10%, 20%, or 30% R are not preferred because blade bending moments would deform the generator and a tight air gap must be maintained. Such devices may also have counter-rotating rotors, with blades passing each other in opposite directions at a small mutual distance (less than R / 5, less than R / 10, or less than R / 50). This has the advantage of achieving high relative speeds between the generator rotor and "stator." However, the mutual blade passing of closely spaced counter-rotating rotors can cause noise and aeroelastic excitations in use. To reduce excitation and noise, it may be suggested to increase the number of blades N and / or use different numbers of blades on different rotors. Even then, such devices are not preferred. The use of counter-rotating rotors of approximately the same diameter (less than 30%, 20%, or 10% difference) may also be inefficient in terms of yield to cost ratio, since a single rotor can already extract almost all of the energy. Compared to co-rotating rotors, counter-rotating rotors have the additional disadvantage of being more disruptive to the scenery, causing more "chaotic" cast shadows, and potentially leading to more obstructions. Finally, direct-drive generators with radii greater than 20% R may lead to various disadvantages, such as increased weight, greater transportation problems, problems maintaining a narrow air gap, and therefore increased costs.

[0242] A medium-sized HAT may be defined as a HAT having a diameter greater than 40 m, greater than 50 m, or greater than 70 m.

[0243] A large HAT may be defined as a HAT having a diameter greater than 100 m, greater than 140 m, or greater than 200 m.

[0244] A small HAT may be defined as a HAT that is smaller than a medium HAT and has a diameter greater than 3 m, greater than 5 m, greater than 110 m, or greater than 25 m.

[0245] A HAT may have one or more downwind and / or one or more upwind rotors. Different rotors of the same HAT may rotate at different speeds. A HAT may be onshore or offshore. A HAT may be installed on a ship. A HAT may have a single foundation with two towers, each tower having one or more rotors with exclusive or (partially) overlapping sweep areas when in use. A HAT may have a single tower, or a tower that splits into one or more arms, each of which may be connected to a rotor.

[0246] A rotor may be a structure of parts that, in use, rotate about the same axis, at the same speed and in the same direction.

[0247] The center of rotation of the rotor is the point on the rotor's axis of rotation that corresponds to the average axial position of the rotor sweep region.

[0248] A HAT has coaxial horizontal rotors when the distance between the centers of rotation of the rotors is less than R / 2, or less than R / 4, or less than R / 10 (R is the radius of the largest rotor).

[0249] The number of blades, "N," may be defined as the number of blades on a rotor. When multiple aerodynamically shaped elongated portions of the same rotor extend along the same longitudinal axis on the same side of the axis of rotation, those portions may be considered portions of the same blade, and those portions may together be counted as one blade. The number of blades may be counted individually for each rotor. For example, if a HAT includes a first rotor with blades extending to position R1 and a second rotor with blades extending to position R2, and the rotors may be designed to operate at different rotational speeds, the number of blades on each rotor may be counted individually. For example, if a HAT includes rotors with blades of different lengths, the number of blades may depend on radial position. For example, a rotor with five long blades reaching 0.1R to R and five small blades reaching 0.1R to 0.6R may be counted as 0.3R(N 0.3R =10) and 10 blades at 0.8R(N 0.8R For example, a rotor with N=5 has 5 blades, but N for the rotor as a whole is 10. In some embodiments, the blades may be assumed to be evenly distributed across the rotor azimuth angle. When a rotor has N blades, this means that the azimuth angle between adjacent blades can be 360° / N±360° / 4N or 360° / N±3 degrees. For example, when N=7, the azimuth angle between adjacent blades is 51.4°±12.9° or 51.4°±3°, such that the minimum azimuth angle between adjacent blades is 38.6° or 48.4°, and the maximum azimuth angle is 64.3° or 54.4°. This even distribution of blades may have any of the following advantages: The rotor is well balanced. The rotor swept area appears as a "closed" and inaccessible surface to birds, a uniform distribution avoids placing the blades too close together and creating deeper cast shadows or core shadows, and the rotor can be more aerodynamically efficient as a uniform azimuthal distribution of the blades results in minimal tip losses.

[0250] The orientation of a longitudinal blade segment may be given by the rotor azimuthal angle φ (φ∈[0°, 360°]) and the polar angle θ (θ∈[0°, 180°]) with the axis of rotation. If a rotor with N blades has multiple aerodynamically shaped elongated segments that can be oriented within 360° / 4N in azimuthal angle and 30° in polar angle, the segments may be considered to be segments of the same blade, and the segments together may be counted as one blade. For example, if a rotor has seven blades, the segments may be oriented within 360° / (4 * 7) = 12.9 degrees difference, and a thin section of an aerodynamic shape that can be oriented within a 30 degree difference in polar angle can be counted as one blade.

[0251] The blade may include a connection side where the blade connects to the hub of the rotor. The blade may be connected to the hub via an intermediate structure, such as a truss structure. The blade further includes a tip side. The radial position of the connection side may be smaller than the radial position of the tip side. Along the length of the blade, the blade may include a stiffening connection that improves structural integrity. The aerodynamic portion of the blade may include a leading edge and a trailing edge. A cross section of the aerodynamic portion of the blade may include an airfoil. Away from the stiffening connection, the blade may be adapted to improve aerodynamics. The blade may include a fixed inner portion and a pitch-adjustable outer portion, or may include only the pitch-adjustable outer portion. The blade may be installed at a fixed pitch angle as a whole, or may be installed to a pitch device to have a variable pitch angle.

[0252] The radial position "r" may be expressed as r = xR, where x∈[0,1] or x∈[0%,100%], and defines the position measured outward from the axis of rotation at a distance x times the maximum rotor radius "R." "In the radial range r = 15%R to R" is equivalent to "for r = 15%R to R." Similarly, "in the blade length range l = 15%L to L" is equivalent to "for l = 15%L to L."

[0253] The local chord c at the radial position r of the blade r" may be defined as the sum of the distances between the leading and trailing edges of all blade segments at a radial location that can contribute to the aerodynamic lift at that radial location when in use. If the blade consists of one segment at a radial location, c r may be the distance between the leading and trailing edges of that section at that radial location. Airfoil extensions due to sound-reducing serrations may not be considered part of the local chord. If the blade has a variable local chord depending on wind speed, for example when a sail may be used, the maximum local chord may be used with the variable section fully extended at position r. At the blade root, where the blade shape often transforms from an aerodynamic shape to a cylindrical shape, the maximum distance of the cross section of the transition at a radial location may be interpreted as the value of the local chord. If the blade consists of multiple aerodynamic shape sections, for example unrestricted radial stays and / or radial compression elements, and connecting joints at different radial locations (greater than 10%R) may contribute to lift in use, the local chord c r may be the sum of the portions of those multiple aerodynamic shapes at radial position r. Blade or rotor parts, such as the hub and / or spinner, that do not generate aerodynamic lift in use may not contribute to the local chord. Tangential stays or tangential compression elements that connect adjacent blades at equal radial positions (equal to within 5% R) at position r are preferably excluded from the local chord. The local chord may refer to the blades of the largest rotor.

[0254] The maximum chord of the blade may be the maximum of the local chord values ​​along the blade length, typically for r=15%R to R.

[0255] Some embodiments have rotors with blades that have a local chord that may be below a certain limit for r = 15%R to R. In such cases, the chord may be greater than the predetermined limit for up to 5%R. This may be useful, for example, to compensate for connections that lead to an increase in chord over a radial range of less than 5%. Such local chord extensions may also be excluded from the maximum chord.

[0256] Rotor solidity "SOLrotor " is calculated by using the following equation 1, which is the local chord c of all N blades of the largest rotor. r can be a mathematical integer over the radial length, e.g., r=0.15R to R, divided by the rotor swept area. Note that the spinner at the center of the rotor does not contribute to SOLrotor. JPEG2026507827000002.jpg13159 (Formula 1)

[0257] Rotor solidity "SOL rotor " may alternatively be the projected area of ​​the rotor, or of a coaxial rotor including the hub and / or spinner, in a plane perpendicular to the rotor axis, with the blades pitched so that the projected area is maximized divided by the (maximum) swept area of ​​the rotor.

[0258] In the case of a ring-shaped wind collector, the chord of the wind collector multiplied by the circumference of the wind collector is called the "SOL rotor " may be added to either of the two definitions above.

[0259] Radial stiffness “sol r ” is the local chord c of all N blades of the rotor at radial position r r divided by the rotor circumference at the rotor radius R (see Equation 2 below). For coaxial rotors, the radial solidity is calculated separately for each rotor. JPEG2026507827000003.jpg14159 (Formula 2)

[0260] Average radial stiffness “avgsol r " may be defined as the average radial solidity of the rotor in the radial range of r-0.1R to r+0.1R. Equation 3 provides an exemplary "avgsol. 25R " is defined as the average radial rigidity between radial positions 0.15R and 0.35R. Similarly, "avgsol. 35R ” may be the average radial stiffness between 0.25R and 0.45R, and “avgsol. 75R" may be an average radial solidity between 0.65R and 0.85R. Note that the radial solidity, radial solidity ratio, and average solidity ratio refer to the largest rotor. JPEG2026507827000004.jpg13159 (Formula 3)

[0261] The undisturbed wind speed "U" may be defined as the speed of the wind through the rotor swept region if the wind were not disturbed by the HAT.

[0262] Power coefficient "C P " is the power "P M It can be defined as the ratio of the kinetic power of the undisturbed wind through the rotor swept region to the power of the undisturbed wind through the rotor swept region (see left side of Equation 4). PE " is the power P produced by the HAT E can be defined as the ratio of the kinetic power of the undisturbed wind through the rotor swept area to the kinetic power of the undisturbed wind through the rotor swept area (see the right side of Equation 4). When the turbine extracts power from the wind, C P is always C PE If the turbine has two rotors with overlapping swept areas, the power coefficient is the sum of the power of both rotors and the swept area of ​​the largest rotor, πR 2 In equations 4 and 5, p is the air density. JPEG2026507827000005.jpg17159 (Formula 4)

[0263] In this disclosure, when the HAT includes two rotors, the axial force coefficient “C D,ax ” refers to the smaller rotor of radius R2, typically referred to as the second rotor, and is the axial force F that the smaller rotor exerts on the wind. ax " and the rotor sweep area πR2 for the small rotor 2 is equal to the ratio of the momentum flow of the undisturbed wind U through JPEG2026507827000006.jpg16159 (Formula 5)

[0264] Design tip speed ratio “λ design” is the angular rotor speed “ω” multiplied by the rotor radius R and the rotor speed C P The ratio at a radial position other than the tip is the radial velocity ratio λ r = λdesign / R (see the right side of Equation 6 below). JPEG2026507827000007.jpg12159 (Formula 6)

[0265] The rotor is typically design Although λ has the highest yield, the HAT control may deviate from this optimum, for example, to reduce load or sound, to avoid natural frequencies, or to avoid excessive power. design Note that refers to the largest rotor.

[0266] The rotor may be designed using known Blade Element Momentum (BEM) theory. Based on BEM, it has been found that for λr>2, an approximation determining the local chord at radial position r to extract more of the energy from the wind can be calculated as shown in Equation 7 below: JPEG2026507827000008.jpg14159 (Formula 7)

[0267] In Equation 7, c l,design may be the design lift coefficient, which is an airfoil characteristic. r c r may be referred to as the composite local chord or "composite chord", which is a rotor characteristic that is a function of radial position and may apply to the largest rotors.

[0268] Cast shadow refers to the shadow of the moving HAT blade. Core shadow refers to the cast shadow where the sun is completely obscured by the moving blade, thereby blocking essentially all direct sunlight.

[0269] It should be noted that every HAT has a shaft, which may be a necessary part to allow relative rotation between the nacelle and rotor, and the shaft may be fixed to the rotor or may be fixed to the nacelle.

[0270] overview Environmental hazards from wind turbines, and in particular from HAT type wind turbines, can take different forms. The following types of hazards are described below: (i) visual (or optical) hazards, (ii) acoustic hazards, and (iii) hazards to birds.

[0271] Visual obstructions may be classified as, for example, direct cast shadow obstructions, indirect cast shadow obstructions resulting in reduced yields of solar farms or crops, and / or obstructions affecting peaceful views. Cast shadows may be shadows caused by blades moving through sunlight. An obstruction to peaceful views may be caused by viewing the moving blades. Larger blades typically result in greater visual obstructions.

[0272] Known solutions to visual obstructions typically involve a design process in which mathematical algorithms can be used to calculate or measure when too large a cast shadow occurs and then determine when to turn off the turbine. Experts in the field generally believe that large rotor blade cast shadows can be unavoidable when wind energy needs to be harvested. Applying transparent blades does not help, as cast shadows are still formed as a result of light refraction, which changes the direction of the light rays. Furthermore, the internal structure of HAT blades, which are typically made of fiber, can be difficult to make transparent.

[0273] The present disclosure proposes to eliminate the core shadow by reducing the local chord to such an extent that the blades no longer visually completely obscure the sun. Traditionally, the sun is often assumed to be a point source of light. However, the inventors have recognized that the sun is visible below an angle of approximately 0.50 degrees above the horizon. Therefore, by reducing the local chord to an angle below 0.50 degrees, the sun is not completely obscured by the blades, and the core shadow can be eliminated.

[0274] The maximum local chord of a known, state-of-the-art blade is typically 7%R, where R is the rotor radius. Applying trigonometry, we can see that such a chord can be visible from a distance of 0.07R / tan(0.50°) = 8R, or 4D (where D is the rotor diameter), down to 0.50°. Thus, for a known HAT of up to 4D, the blade casts a core shadow. As proposed in embodiments of the present disclosure, reducing the maximum chord by, for example, halving the known maximum chord to 3.5%R results in the core shadow reaching only a distance of 0.035R / tan(0.50°) = 4R, or 2D, in this example. This means that the core shadow no longer occurs in the significant range of 2D to 12D from the HAT, i.e., the range where visual obstructions are primarily perceptible. Cast shadow obstructions typically include both core shadows and partial shadows. Furthermore, partial shadows can be minimized, i.e., half the "depth" in the given example. Advantageously, the present disclosure may achieve a reduction in visual obstruction by about a factor of two or more, such as a factor of two in the above example, by reducing the maximum chord of the state of the art.

[0275] An additional benefit of having less deep or core shadows from wind turbines is the yield of photovoltaic solar panels located in the shadowed areas. Reducing shadow depth is advantageous because the power of a particular solar system consisting of a series of solar panels can be approximately proportional to the power of the panel with the lowest yield, and therefore the panel that is in the deepest shadow.

[0276] With respect to the tranquility of the view, large moving blades in particular can attract attention and elicit stress responses because their movements may be perceived as dangerous. This type of disturbance is often less annoying than cast shadows, but it can occur more frequently. This disturbance affects most of the daytime and can be annoying up to 50 diameters from the HAT in clear weather. Unlike cast shadow disturbances, this type of disturbance is not limited to the shadow area, but instead affects nearly the entire turbine perimeter, up to 10-50 diameters from the HAT. Disturbances can be estimated to reach a visual distance of approximately 20D on average, and the circular area around the turbine where disturbances can occur is approximately π(20D) in size. 2 Assuming that this disturbance occurs approximately 50% of the time during the day (e.g., excluding nighttime hours), which could be approximately 4400 hours per year, the disturbance frequency for impacts on view tranquility is approximately π(20D) 2 ·4400h=7040000·1 / 4πD 2 m2 h It could be.

[0277] In comparison, cast shadow damage can typically be limited to an area about four times the sweep area (assuming the sun is 15 degrees above the horizon) and occurs only in direct sunlight, with about 1500 occurrences per year in the Netherlands, for example. Therefore, for cast shadows, we calculate the frequency to be about 1 in 1200, or 4 1 / 4πD. 2 1500m 2 h=6000·1 / 4πD 2 m 2 h.

[0278] The inventor's insight is that by reducing the maximum chord by a factor of two, the distance at which the background blades visually disappear is approximately halved. This can be understood optically because the angle at which the half-maximum chord is visible at half the distance can be equal to the angle of the full maximum chord blade at full distance. Thus, the visual obstruction can be reduced in distance by a factor of two, and thus the obstruction area and obstruction frequency can be reduced by a factor of four. While the above-described embodiments may be based on the maximum chord, similar logic can be applied to local chords as well.

[0279] The maximum chord reduction and local chord reduction provided by the present disclosure may be particularly advantageous for medium and large HATs, and for small HATs, the maximum chord reduction and local chord reduction may also be advantageous.

[0280] Regarding acoustic interference from wind turbines, it has been found that aerodynamic sound pressure levels can be approximately proportional to the fifth power of the blade tip speed, and therefore, reducing the tip speed can reduce noise from rotating blades. However, because the aerodynamic lift generated by HAT blades is approximately proportional to the square of the tip speed, reducing the tip speed requires a square increase in blade chord to maintain the required lift. Thus, blade chord increases all kinds of problems associated with large chords, such as increased visual obstruction, transportation size, and production issues. Therefore, a solution that reduces tip speed is undesirable.

[0281] The inventors have discovered that, contrary to conventional wisdom, it may be better to reduce the chord rather than increase it in order to reduce noise. It has been discovered that reducing the chord and / or reducing the tip speed can be complemented by, for example, increasing the number of blades. Increasing the number of blades may be particularly advantageous for medium and large HATs. It may also be advantageous for small HATs to increase the number of blades.

[0282] In this disclosure, a HAT may be considered to be optimized for yield or yield to cost ratio, or total CO2 emissions or circulation avoided, e.g., having a power coefficient of at least 0.35. Additionally, medium, large, and small HATs are preferably able to withstand greater wind speeds, including extreme wind speeds of, e.g., 40 m / s.

[0283] For current-technology HATs, the general consensus is that the optimal number of blades for a medium- or large-sized power-generating HAT is three, or perhaps two. Other blade counts are typically not considered for medium- or large-sized HATs intended for power generation, and those skilled in the art would typically not consider increasing the number of blades in a HAT. A known argument for choosing three blades over four or more blades is that the power coefficient does not improve significantly (perhaps 1%) with more than four blades. Furthermore, every additional blade requires additional handling during transportation, lifting, and maintenance. Furthermore, there may be arguments regarding blade loads comparing a rotor with three blades to another rotor with more blades, e.g., six blades. Each blade in a three-bladed rotor experiences double the load and double the chord and thickness compared to each blade in a six-bladed rotor. Because of the double load, the bending moment may also be doubled, but the double-thickness structure has four times the bending stiffness when the same amount of material can be used. Thus, using three dual-loaded blades requires less material than, for example, six single-loaded blades, and so known HATs prefer three blades over more blades.

[0284] The inventors have discovered that having four or more blades can have a positive acoustic impact. Generally, three potential sources of acoustic interference can be distinguished: (i) total sound pressure level, (ii) amplitude modulation (AM), and (iii) inaudible sounds. AM means that the sound of the HAT is not constant; the passage of individual blades can be heard as a loud, repetitive "whoosh" noise. Using four or more blades has been found to reduce AM sounds. For example, AM can be reduced by about a factor of five by changing from three to five blades. Further AM reduction to a nearly constant sound pressure level can be achieved with seven or more blades. This is particularly true for medium and large HATs, but also applies to smaller HATs to a lesser extent because the rotational speed of smaller HATs is so fast that individual blade noise is indistinguishable.

[0285] With regard to inaudible sounds, it was found that changing the rotor design from the traditional three-chord blades to a greater number of short-chord blades shifts the audible frequency distribution toward higher frequencies. This reduces the proportion of inaudible sounds and increases the proportion of high-frequency sounds. The shorter the local blade chord, the less thick the boundary layer stack is on the blade surface, thus thinning the boundary layer and introducing high-frequency noise. Additionally, short-chord blades pass through the pressure field around the tower more quickly, thus shifting the source of this sound toward higher frequencies. Advantageously, because high frequencies may be better attenuated in the atmosphere, while low frequencies are not, the shift toward higher frequencies may be perceived as less annoying.

[0286] As shown in Equation 7 above, reducing the chord and increasing the number of blades are related. From Equation 7, for a given c l,design and λ r In the case of N and local chord c r It can be said that the product of preferably satisfies a specific value. As will be further explained below, a reduction in chord can be compensated for by an increase in the number of blades, and vice versa. If an observer is at a distance of 3 diameters (3D = 6R) behind the turbine, and we want to limit the visibility of the blades to less than 50% of a solar angle of about 0.5 degrees, and therefore less than about 0.25 degrees, then the blade chord should be about tan(0.25 degrees). * 6R = 0.026R. Substituting this into Equation 7, r = 0.4R, λ r = 3.2, and c l,design = 1.5, the estimated number of blades N can be 5.2, so that essentially five or six blades can be used instead of the conventional three.

[0287] Therefore, it may be preferable to reduce acoustic obstruction through a combination of lower tip speed, reduced chord, and increased blade count, which minimizes visual and acoustic obstruction while maintaining yield.

[0288] Bird-related hazards include bird accidents caused by direct collisions between the HAT and birds. Bird-related hazards can also be caused by, first, the impact of air pressure near the rotating blades, and, second, non-contact overloading of birds due to the high speed / low air pressure of vortex flows from the blade tips. If the number of blades applied to a HAT rotor is increased and the chord is reduced, the lift per blade can be reduced, for example, according to Equation 7. The inventors have insight that this reduces the area around the blade where a specific air pressure is induced by the blade, reducing the strength of the tip vortex, and therefore making the rotor less dangerous to birds.

[0289] The risk to birds for a rotor of diameter D with N blades can be expressed as follows: The boundary vorticity "Γ" can be thought of as proportional to D and inversely proportional to N, so Γ = kD / N. The risk space S to birds due to N tip vortices of strength Γ is Γ can be a space where the velocity induced by the vortex flow can exceed a certain limit. In a plane perpendicular to Γ, the width and height of this space can be proportional to Γ and the length of the space in the direction of Γ, respectively, and can also be proportional to Γ. Therefore, the space S Γ =k2NΓ 3 Here, substituting Γ=k1D / N, S Γ =k2N(k1D / N) 3 =k3D 3 / N 2 (where k, k1, and k2 are constants).

[0290] The effect of air pressure on the bird can be expressed as follows: P is considered to be proportional to the square of the boundary vorticity and proportional to the blade length, which is proportional to D, so SP=c1DΓ 2 Substituting Γ=k1D / N again, we get S P =cD 3 / N 2 where c and c1 are constants.

[0291] The inventors have insight that the vortex and / or pressure related danger space for birds on a rotor of diameter D decreases with the number of blades, and specifically decreases as the square of the number N of blades.

[0292] Bird accidents due to blade strikes may occur less frequently when the entire swept area of ​​the rotor is more visible to birds and when the blades move at slower speeds. Lower blade speeds give birds more time to react and avoid a collision with the blade, and if a collision does occur, the impact is less severe. At lower blade speeds, in one embodiment, conventional λ design For conventional offshore turbines, λ design Typically, λ may be in the range of 9 to 10. In one embodiment, design ≦9, and preferably λ design ≦8, more preferably λ design is about 7. For conventional land-based turbines, λ design Typically, λ can be in the range of 8 to 9. In one embodiment, for terrestrial HAT, λ design ≦8, and preferably λ design ≦7, more preferably λ design ≦6, and more preferably λ design ≦5.

[0293] To improve the visibility of the rotor swept area to birds, in one embodiment it may be preferable to have at least four or five blades, and preferably at least six or seven blades, since a rotor with more blades will appear as a "closed" and inaccessible surface to birds. On the other hand, a rotor with two or three blades will have large open areas between the blades which may "guide" birds to fly through the open areas, increasing the risk of collision when the rotor is rotating.

[0294] Therefore, to avoid bird accidents, a low rotational speed and / or a high number of blades may be preferable. At low speeds, a large composite chord N is required to keep the efficiency high. rc r may apply, even for a large number of blades.

[0295] In one embodiment, the HAT may include controls to minimize the impact of shading on crops or solar energy systems such as photovoltaic panels by swaying the HAT, rotating the rotor, and pitching the blades so that the impact of shading can be minimized during periods of direct sunlight when the turbine cannot generate much energy, for example, due to low wind speed or malfunction. During these periods, the yaw and / or pitch position of the blades and / or the rotor azimuth angle may be adjusted, possibly individually, depending on the position of the sun so that shading of the generating unit can be minimized and / or the cross section of the blades in a direction perpendicular to the sunlight can be minimized.

[0296] In one embodiment, solar panels in an area that may be shaded by the HAT may be divided into groups, with the panels connected in series within the group and the groups connected to inverters with maximum power point tracking, so that panels within the same group are shaded or unshaded as simultaneously as possible depending on the position of the sun. For example, it may be advantageous for all panels of the same group on the north side of the HAT to be located in a pie-shaped area around the tower, particularly at least three tower diameters from the tower.

[0297] Turbine diameter can play a significant role in all sources of disturbance. The rotor area exposed to direct or indirect sunlight, the total sound pressure level, and the area at risk for birds are roughly proportional to the square of the diameter. The contribution of low frequencies to HAT sound increases with turbine size. Low frequencies generally cause more problems than high frequencies. The impact of the hissing sound from individual blades also increases with turbine size. For small turbines with diameters less than 5 m, this effect is nearly nonexistent. These turbines rotate at such high speeds that individual blade sounds are inaudible. For medium-sized wind turbines with diameters greater than 40 m and larger wind turbines with diameters greater than 100 m, rotor speeds can be slower, and individual blades on two- or three-blade turbines may be discernible. Furthermore, the visual impact of small HATs can typically be reduced because buildings and trees can obscure them.

[0298] In one embodiment, the HAT may be a medium-sized HAT.

[0299] In another embodiment, the HAT may be a large HAT.

[0300] In one embodiment, the HAT of the present disclosure has the same radial stiffness sol for r=15%R to R. r The samples may be made in serial production so that at least two specimens of the same diameter can be produced.

[0301] Hazards to rare birds are typically considered to be of greater importance than hazards to more common birds. Rare birds are often predatory birds and typically fly at high altitudes, which may be the altitudes of medium and large HATs. Thus, the larger the turbine, the more significant the various hazards, and therefore, the present disclosure may be particularly relevant to medium and large HATs.

[0302] Further Exemplary Embodiments In one embodiment, the HAT is designed to have a tip speed ratio λ design The number N of blades at 60%R may be N0.6R,min =INT(100π / λ design 2 +0.5) and N 0.6R,max =2 N 0.6R,min Preferably, N is considered to be a prime number or a double of a prime number. For example, λ design For example, when N = 7, 0.6R,min =INT(100π / 7 2 +0.5) = 6 and N 0.6R,max =12, where the INT function returns an integer value, i.e., a number with no fractional part. If the number of blades is prime, the lowest rotor natural frequency may correspond to the inverse of the rotor rotation period, and the next natural frequency is N times higher; it may be preferable to have large separations between the rotor natural frequencies.

[0303] In one embodiment, the required lift may be generated by an airfoil with a high design lift coefficient so that radial rigidity may be kept to a minimum. l,design ≧1.4, preferably c l,design ≧1.6, more preferably c l,design ≧1.8, more preferably c l,design ≧2.0, more preferably c l,design Apply an airfoil that is ≧2.2 and may have vortex generators at locations 0.5R, 0.7R, and 0.9R. For the design lift coefficient, the lift coefficient of the airfoil with the highest lift to drag ratio may be selected.

[0304] Instead of using the lift coefficient at the maximum lift-to-drag ratio as the design lift coefficient, the lift coefficient c at angles of attack of 4 to 9 degrees or 5 to 8 degrees before the stall angle is used. l It has been found that it can be advantageous to apply as the design lift coefficient. The stall angle may be the minimum positive angle of attack α (derivative dcl / dα=0 in a 2D situation). The advantage of using this latter design lift coefficient is that a larger, shorter chord blade can be used to achieve the required lift, which may reduce optical obstruction and favor loading.

[0305] The airfoil characteristics may preferably be effective under operating conditions of, for example, 8 m / s wind speed and for Reynolds numbers consistent with the HAT's design.

[0306] In one embodiment, the HAT of low environmental interference is a maximum power coefficient C measured behind the generator that may be higher than 0.30, preferably higher than 0.35, more preferably higher than 0.40, more preferably higher than 0.45. PE This can be achieved by having:

[0307] The present disclosure may not be limited to land-based HATs. The present disclosure may also provide particular benefits to offshore HATs. It should be recognized that visual and noise disturbances may also be directed to certain species of marine or freshwater animals and / or people working or recreating on the water. Furthermore, offshore turbines may be visible from the shore and cause the aforementioned disturbances to tranquil scenery or tranquil ocean views. Therefore, contrary to conventional belief, offshore turbines may also be a source of environmental disturbance. Furthermore, certain embodiments are described as having a higher cost-to-benefit ratio. Thus, in one embodiment, the HAT may be an onshore or offshore turbine.

[0308] Similar to the unexpected visual and acoustic benefits of offshore turbine embodiments, these benefits also apply to terrestrial natural areas where animals are abundant, as animals may also be annoyed by noise, cast shadows, disturbances to tranquil views, and / or bird accidents. Additionally, wind turbines with fewer accidents according to certain embodiments are preferred in natural areas where more birds typically fly. The benefits are valid for all wind turbines with four or more blades according to certain embodiments. Because natural areas have many trees, and therefore only medium-sized or large wind turbines whose swept areas are typically at high altitudes above tree height are economically efficient, the benefits may be greater for medium-sized wind turbines and even greatest for large wind turbines.

[0309] The inventors have found that using small chord blades in combination with rotors having four or more blades not only reduces interference but also increases the yield-to-cost ratio, which may be particularly important for medium-sized wind turbines and even more important for large wind turbines. Notably, for some embodiments where the number of blades is increased, e.g., from three to five, the yield increases by approximately 1%, and for a further seven blades, the yield increases by approximately 1.5%. For four or six blades, the yield increase may be somewhere between these values. For eight or more blades, the additional yield increase may be less. The reason for this yield increase is that tip losses, often explained by "Prandtl tip straightening," are reduced with more blades.

[0310] Additionally, current state-of-the-art turbines occasionally need to be shut down due to failures, but the HAT of the present disclosure is less prone to failures, resulting in less or no failure-related downtime and an estimated 1% to 2% additional yield.

[0311] Blade production and transportation tends to be more problematic as turbine size increases, and reaching certain HAT sides may be practically impossible. Advantageously, in one embodiment, using a larger number of blades with shorter chords and / or shorter lengths is less expensive than a conventional smaller number of blades with larger chords and / or longer lengths.

[0312] While those skilled in the art typically focus on high yield per unit of rotor swept area, the present disclosure focuses on parameters such as yield to cost ratio, total CO2 emissions avoided, or circularity. It can be seen that the blade area closer to the tip harvests more energy per blade than the blade area closer to the rotor center. Solidity Nc r / (2πr) can be calculated at two radial positions, for example, r=0.3R and r=0.9R. (c l = 1.5, and λ design= 8) and using Equation 7, Nc r / (2πr) r=0.3R =0.104 and Nc r / (2πr) r=0.9R= 0.0116. Therefore, at the blade root, the required blade surface area may be approximately nine times larger than at the tip, at 0.104 / 0.0116 per swept area. And because the energy captured is approximately proportional to the swept area, the airfoil at the root captures approximately one-ninth as much energy per unit of chord length as the airfoil at the tip. During hurricane wind speeds, when the HAT must be shut down to avoid damage, the loads exerted by the blade at the base of the tower may be approximately proportional to the blade area. Thus, the blade root generates high wind loads but harvests relatively little energy, while the blade tip performs approximately nine times better in terms of yield to load ratio. The inventors recognized that it would be better to accept generating less power near the rotor center, thereby increasing the yield to load ratio. Therefore, in one embodiment, the blade area at the blade root may be less than the area that would be required to obtain maximum power extraction (the Lanchester-Betts limit). Although power extraction in the root region (below 0.35R or even below 0.45R) may fall below 50% or 25% of the optimum, or even approach zero, the yield-to-cost ratio of the wind turbine may be increased. Utilizing the lower blade area of ​​the blade at the root further means that rotor solidity may be reduced, which has the added benefit of less damage to the yield of crops and solar panels that may be located in the rotor's shadow. Furthermore, reduced chord at the root has the advantage of casting less shadow and disrupting the tranquility of the view. Furthermore, when bird visibility is poor, such as at night or in heavy fog, the number of bird casualties is roughly proportional to the projected area of ​​the wind turbine rotor, so reducing chord at the root, and therefore rotor solidity, is advantageous. Using these arguments, in one embodiment, the radial solidity near the rotor center may be reduced relative to the radial solidity near the tip. The ratio of the radial solidity of the rotor at a radial position of 0.25R to the radial solidity of the same rotor at a radial position of 0.75R is sol 0.25R / sol 0.75RR, which may be less than 2.0, preferably less than 1.75, more preferably less than 1.5, more preferably less than 1.25, more preferably less than 1.0, and more preferably less than 0.90. Efficiency advantages may also be realized for HATs with exactly two or exactly three blades that reach a radial position of 0.90R, particularly for exactly two blades with a maximum chord of less than 9%R or 8%R or 7%R, since blades with such low maximum chords also have less optical obstruction, are easier to produce, and are simpler to transport.

[0313] In one embodiment, the HAT comprises a rotor with exactly two blades reaching a radial position of 0.90R and having a maximum chord of less than 9%R.

[0314] In one embodiment, the HAT comprises a rotor with exactly two blades reaching a radial position of 0.90R and having a maximum chord of less than 8%R.

[0315] In one embodiment, the HAT comprises a rotor with exactly two blades reaching a radial position of 0.90R and having a maximum chord of less than 7%R.

[0316] In one embodiment, at the radial position of 0.25R, the aerodynamic blade section is partially or completely replaced by a structural element, thereby 0.25R / sol 0.75R In an extreme example embodiment where there are only structural elements with no aerodynamic shape contributing to lift at 0.25R, sol 0.25R / sol 0.75R can even be 0, which may be preferable as explained above, and may also be preferable for embodiments with a second, smaller coaxial rotor designed for higher rpm, which may be more efficient at 0.25R (where R is the radius of the large rotor).

[0317] In one embodiment, the ratio sol 0.25R / sol 0.75RSimilarly, the average solidity ratio avgsol. 25R / avgsol. 75R and avgsol. 35R / avgsol. 75R may also be less than 2.0, preferably less than 1.75, more preferably less than 1.5, more preferably less than 1.25, more preferably less than 1.0, more preferably less than 0.90, more preferably less than 0.75, more preferably less than 0.50, and more preferably less than 0.25.

[0318] For example, the radial solidity of the rotor at 0.25R divided by the radial solidity of the rotor at 0.75R may be less than 2.0. 0.25R / sol 0.75R may be equal to 1.9, 1.7, 0.8, or 0.1.

[0319] As a result of reducing the radial stiffness near the root at a radial position less than 0.6R, in one embodiment, the HAT has a radius of f / λ design 2 Rotor solidity SOL, which can be less than rotor where f is a factor less than 2.0, preferably less than 1.8, more preferably less than 1.6, and more preferably equal to about 1.35.

[0320] In one embodiment, a rotor with low rigidity near the rotor center may be applied, since in this range the ratio of yield to wind load may not be beneficial for state-of-the-art HATs. Therefore, in one embodiment, we use an average radial rigidity avgsol at r=0.25R. 25 In one embodiment, a HAT having a rotor with avgsol. is proposed. 25 is less than 0.06. In one embodiment, avgsol. 25 is less than 0.05. In one embodiment, avgsol. 25 is less than 0.04. In one embodiment, avgsol. 25 is less than 0.03.

[0321] For offshore turbines, the yield to cost ratio may be more important than reducing interference. Thus, in one embodiment, the HAT may have a rotor with two or more blades reaching a radius R that may be at least 70 m. The ratio of the radial solidity of a rotor at a radial position 0.25R to the radial solidity of the same rotor at a radial position 0.75R is sol 0.25R / sol 0.75 The radius of curvature of the offshore HAT may be expressed as R and may be less than 2.0, preferably less than 1.75, more preferably less than 1.5, and more preferably less than 1.25. In one embodiment, such an offshore HAT may have five blades that span a radius of R.

[0322] For land-based HATs, both yield to cost ratio and reduced interference can be important. Thus, in one embodiment, the HAT may have a rotor with five or more blades reaching a radius of R. The ratio sol 0.25R / sol 0.75R may be less than 2.0, preferably less than 1.75, more preferably less than 1.5, more preferably less than 1.25. In one embodiment, such a land-based HAT may have seven blades that span a radius R.

[0323] In one embodiment, at least one of the blades may include a blade section. Such a section may have a variable cross-section if it has a difference in cross-section over its length. Such a variable cross-section may consist of a pultruded airfoil section integrated into one or more separately produced structural elements.

[0324] Potential problems can arise with pultruded blade sections. While a pultruded product may have a constant cross-section in the direction of pultrusion, the desired characteristics of a HAT blade may be a varying aerodynamic shape and varying bending stiffness along the blade's length. By placing structural elements of different lengths in the pultruded airfoil section's void, the cross-section may vary along the blade's length, and the bending stiffness may vary accordingly. If the pultruded airfoil section's void is cylindrical with its axis aligned with the torsion axis, cylindrical structural elements of different lengths may be inserted into the void and cured to create a pultruded airfoil section with varying bending stiffness along the blade's length. An advantage of using pultruded airfoil sections is that the pultrusion process allows fibers to be cured without wrinkles, resulting in efficient use of composites, which can lead to weight and cost savings. Furthermore, the pultrusion process can be better controlled than processes in which the blade is made in a single piece in a mold. Such better control can lead to reduced production uncertainty and therefore reduced oversizing requirements. Additionally, the use of pultrusion can improve the airfoil shape and surface quality, thus increasing yields compared to processes that create blades in a single piece with larger molds.

[0325] In one embodiment, the blade section may include a cylindrical void having an axis that is coincident with the twist axis of the pultruded twisted airfoil section. The separately integrated structural element may be a cylindrical element that fits into the cylindrical void. The cylindrical element may be pultruded.

[0326] In one embodiment, the pultruded airfoil section may be twisted by counter-rotating the cylindrical structural element and the pultruded airfoil section and connecting them under prestress.

[0327] In one embodiment, the reduced chord blade may include a blade section that includes a pultruded twisted aerodynamic section, which may result in more optimal use of composites and / or better surface quality and / or avoid the need for a large mold to make the blade in a single piece.

[0328] In one embodiment, at least one section of the blade may be injection molded or 3D printed, and the section may include the tip of the blade, or the section may include a transition from one blade section to another blade section of a different chord length.

[0329] In one embodiment, one or more of the blades may include vortex generators having cambered fins. The fins may have a fin thickness that is about 95% of the fin height. The fin thickness may be at least 0.5 mm. Alternatively, the fin thickness may be at least 0.7 mm. Alternatively, the fin thickness may be at least 1 mm. Alternatively, the fin thickness may be at least 2 mm.

[0330] In one embodiment, one or more of the blades may include a vortex generator having a base plate and cambered fins. The fins may extend at an angle relative to the normal of the base, the angle may be greater than 0.5 degrees. Alternatively, the angle may be greater than 1 degree. Alternatively, the angle may be greater than 3 degrees. Alternatively, the angle may be greater than 10 degrees. Alternatively, the angle may be approximately 15 degrees. Alternatively, the angle may be less than 50 degrees.

[0331] In one embodiment, at least one of the blades may include a vortex generator pair having at least two mirror fins designed to generate counter-rotating vortices. Each fin of the vortex generator pair may have its own base plate so that the fins are individually attached to the blade and the distance between the fins can be controlled.

[0332] In one embodiment, at least one of the blades may include a vortex generator on the suction side of the blade. The vortex generator may be located at a radial position greater than 60%R and a chordal position greater than 60% of the local chord. Alternatively, the chordal position may be greater than 70%. Alternatively, the chordal position may be greater than 80% of the local chord. Alternatively, the chordal position may be greater than 90% of the local chord. Advantageously, such vortex generator(s) may further reduce the sound at the trailing edge of the rotating HAT blade.

[0333] Equation 6 is a high design lift coefficient c l,design By using the composite string N r c r This indicates that high c can reduce the l,design Reducing disability using high c l,design It may be advantageous to apply an optimized vortex generator to obtain

[0334] In one embodiment, the HAT may have a blade including a pultruded aerodynamic section extending over more than 50% R, preferably more than 60% R, and more preferably more than 70% R. The pultruded blade section may include features to enhance the design lift coefficient by increasing the distance to the blade tip, which may include the use of vortex generators and / or Gurney flaps. The blade of this example may include exactly one pultruded blade section. This has the advantage that no connections are required between pultruded sections, making the blade simpler, cheaper, and more precise in terms of shape, resulting in a high yield-to-cost ratio. The blade of this example may be designed for a five-blade rotor with a diameter D, with the advantage that the blade can be extended by a factor of 7 / 5 by increasing the length of the pultruded section to fit a seven-blade rotor with a diameter of 7 / 5D. Conversely, the blade length can be shortened by 3 / 5 so that a shorter blade can be used for a three-blade rotor with a diameter of 3 / 5D. The pultruded blade section of this example may be twisted during or after the pultrusion process. If the same pultrusion die can be used to produce blades for different rotors, the twist per unit length of the blade can be increased or decreased to keep the twist per %R approximately the same. The twist rate can be adapted by applying torque to the blade during the pultrusion process. These embodiments have the advantage of inexpensive, high-quality pultruded aerodynamic sections, designed to have near-optimal aerodynamic efficiency at approximately 80%R or 90%R, with this efficiency decreasing toward the main axis. This design takes advantage of the aforementioned effect that the tip harvests more energy per blade area unit than the blade area near the rotor center, thereby improving the yield-to-load ratio and reducing optical obstructions due to the lower radial solidity at smaller radial locations and the lower overall rotor solidity.

[0335] In one embodiment, the drawn forming blade section may include a prehub trailing edge that can be supplied through a drawn forming die and integrated in the drawn forming section. The advantage is a thin trailing edge of good shape that can be less prone to damage.

[0336] In one embodiment, at least one of the blades may include a strip attached to the blade trailing edge. The strip may have a trailing edge thickness of less than 2.0 mm or less than 1.0 mm over 50%R. Alternatively, the strip may have a trailing edge thickness of less than 1.0 mm or less than 0.5 mm over 25%R. Alternatively, the strip may have a trailing edge thickness of less than 0.5 mm or less than 0.3 mm over 10%R. Such a trailing edge strip has the advantage of reducing the trailing edge noise of the HAT blade and can improve the structural integrity of the trailing edge of the blade.

[0337] To reduce the bending moment of the blade, particularly the bending moment having a direction vector in the rotor axis direction, the inventor recognized that a tangential stay can be effective without causing significant aerodynamic drag. A tangential stay refers to a connection from one blade at a specific radial position to an adjacent blade at approximately the same radial position. In one embodiment, the HAT may have a first blade and a second blade that are part of the same rotor, and the blades may have a tangential connection at a radial position R3, where R3 > 0.20R, preferably R3 > 0.30R, more preferably R3 > 0.40R, and even more preferably R3 > 0.45R. Additionally or alternatively, R3 < 0.8R, more preferably R3 < 0.70R, more preferably R3 < 0.60R, and even more preferably R3 < 0.50R. In one embodiment, 0.20R < R3 < 0.80R, preferably 0.30R < R3 < 0.70R, and more preferably 0.40R < R3 < 0.60R.

[0338] In one embodiment, the blades may include pitch-adjustable outer sections that do not need to be fixed to the center of rotation at r less than 0.20R, but instead may be fixed at a radial position of 0.25R or greater. This has the advantage that the pitch-adjustable outer sections are shorter in length, and potentially shorter in the chord direction, making them easier to handle and transport. Furthermore, the bending moment exerted by the blades increases the closer they are to the rotor center. By fixing the outer blade sections at a greater radial position, the section with the greatest bending moment, which may be the most expensive section, can be eliminated. If the outer blade sections can be fixed to pitch bearings that can be located at a greater radial position, the pitch bearings can be less loaded and less expensive than conventional pitch bearings located at a radial position less than 0.2R. Calculations have shown that a rotor with blades in the range of 0.4R to 1.1R, e.g., 0.7R, generates 7% more energy and has lower blade and pitch bearing costs than a rotor with blades in the range of 0.05R to 0.95R (R refers to the radius of the latter conventional rotor). Blades in the 0.4R to 1.1R range may also be less expensive than blades in the 0.05R to R range. The structure required to replace a "stripped" blade root of about 0.05R to 0.4R in this example may be less expensive than the "stripped" blade root.

[0339] In one embodiment, the HAT includes a rotor, and bending-inducing forces by the blades can be reduced by application of stays. In one embodiment, the stays and blades can be connected by stay holders at radial positions between 0.25R and 0.65R, and the stay holders are preferably pivotally secured to the blades to allow pitch adjustment of the blades over at least 30 degrees, preferably at least 60 degrees, and more preferably at least 90 degrees.

[0340] In one embodiment, rotors with a diameter greater than 100 m, including truss structures and / or reduced-length blades and / or four or more blades, may offer additional advantages during rotor installation. Blade weight and / or blade length are smaller compared to current-state rotors with two or three blades, and thus the blades can be lifted more easily. For the same reason, rotor imbalance may be reduced when installing one blade on a rotor with four or more blades compared to installing one blade on a rotor with two or three blades. With only one blade installed, it may be easier to rotate the rotor to an azimuth position where the next blade can be installed. With three-bladed rotors, rotor imbalance can be a problem when rotating a rotor with two of its three blades installed to the appropriate position to install the third blade. This problem may be reduced with rotors with four or more blades. For example, if a rotor has five blades, say at positions 1 through 5 in increasing azimuth angles, and the first blade is installed at position 1, the next blade can be installed at position 3, again reducing imbalance compared to a situation where only two blades of a three-bladed rotor can be installed. In a method of installing a HAT with four or more blades, after the first blade is installed on the rotor, a second blade is installed at a rotor position that is not adjacent to the first blade already installed.

[0341] In one embodiment, a control issue with current-state rotors may be addressed. The control issue may occur in the wind speed range between rated wind speed and cutout wind speed. In this range, rotor blades can typically adjust the pitch of their vanes to control power so as not to exceed the generator's maximum power and / or a certain maximum load level. Just before cutout wind speed, the blades can typically adjust the pitch of their vanes so that the blade tips have negative lift, accelerating the wind and absorbing power, or in other words, generating negative power. The innermost blade area may generate more power than the maximum allowable value. The total power, equal to the power generated by the innermost blade portion plus the negative power from the tips, may be the maximum power the generator will absorb. This situation may be load sizing. The tips may flex in the opposite direction to operation below rated wind speed, or even stall, causing high loads. This adverse effect can be the result of pitching the entire blade along its entire length as a single piece, with the blade root mounted near the center of rotation and the tip reaching the radius.

[0342] In one embodiment, the above control problem can be reduced by a HAT including at least a first blade, which can be a member of a first rotor, and a second blade, which can be a member of a second rotor, where the first blade reaches a radial position R and the second blade reaches a radial position R2. The first blade can be designed for a first range of rotational speeds, and the second blade can be designed for a second range of rotational speeds. Advantageously, in these embodiments, the first blade and the second blade can be individually controlled, thereby reducing the above control problem. The first rotor can be optimized to extract energy from a flow in the range from radial position R2 to radial position R, while the second rotor can be designed to extract wind energy in a radial range below R2. The first rotor and the second rotor can rotate about the same axis.

[0343] In one embodiment, the HAT may have a diameter greater than 1 meter and less than 50 meters. Such a HAT may have a trailing vane that aligns the turbine with the wind, and the trailing vane surface may be hinged to the trailing side, and the surface may be oriented in a direction perpendicular to the πR 2 / 10 or greater than πR 2 / 5 or greater than πR 2 Greater than / 2, 1 / 2D 2 Larger, 3 / 4D 2 Bigger, D 2 Larger and 1 1 / 2D 2 Greater than.

[0344] In one embodiment, the HAT may have blades that include pultruded airfoil sections, possibly with twist.

[0345] Thus, it has been discovered that the present disclosure provides many further advantages. Embodiments of the present disclosure notably and advantageously can address multiple sources of environmental hazards while improving the yield to cost ratio of HATs for any one or more of the following reasons: (i) reduced tip losses, (ii) reduced downtime due to reduced hazards, (iii) lower solidity and / or low sol 0.25R / sol 0.75R (iv) good ratio between yield and wind load due to the dual rotor concept; (v) inexpensive rotor due to truss structure and / or stays; (vi) reduced manufacturing costs due to the use of blades with reduced length and / or reduced chord and / or pultruded blade sections; (vii) control advantages in wind and snow; (viii) easier logistics and installation due to reduced blade length and / or blade chord; (iix) reduced rotor imbalance during installation when four or more blades may be applied.

[0346] Table 1 below lists exemplary types of environmental disturbances in the "Disturbance" column. The "Measures" column lists measures that can attenuate the specified type of disturbance. The measures can have a consequential effect on the HAT design, examples of which are shown in the "Results" column. For example, cast shadow disturbance can be reduced by using blades with reduced chord (Measure: "Short Chord"), so that the number of blades N can preferably be increased ("Large N") to maintain high HAT efficiency, for example, based on Equation 7. Cast shadow disturbance can also be reduced by using blades with reduced chord (Measure: "Short Chord"), so that the number of blades N can preferably be increased ("Large N") to maintain high HAT efficiency, for example, based on Equation 7. 25R / avgsol. 75R or avgsol. 35R / avgsol. 75R This is reduced by a high solidity ratio such as λ, because a high solidity ratio is accompanied by a reduction in the local chord near the rotor center, and thus a reduction in the cast shadow. design Also, λ design By increasing the SOL ROTOR is reduced, leading to reduced cast shadows. design and / or related to bird incident hazards that can be reduced by means of large N. Low λ design The result of, for example, λ r =λ design By Equation 7, where r / R, the composite string N r c r Increase in "large N r c r "). Large composite strings can have large N ("large N r c r →large N"). Other exemplary obstacles, measures, and results can be seen in Table 1. [Table 1]

[0347] From Table 1, we can see that certain measures are inconsistent. For example, low λ design reduces the sound pressure level but at the same time increases the cast shadow, so the choice of the designer depends on the situation.

[0348] The inventors' insight is that increasing the number of blades N may be beneficial for most or even all of the listed obstacles. design Assuming that σ is still approximately the same, and thus the composite strings are approximately the same, it may be suggested that a reduced string reduction is favorable for the fault. Therefore, some embodiments define a string below a certain limit.

[0349] Obviously, Table 1 refers to wind turbines with the same diameter D, and reducing the diameter is not a meaningful means of reducing interference, since yield decreases approximately as the square of the diameter. This emphasizes that the present disclosure is important for wind turbines of all sizes, especially medium and large wind turbines.

[0350] A higher blade count can add approximately 1% to 1.5% to yield due to lower tip losses. Fewer failures translate into less downtime at failure costs, which can add another 1% or 2% to yield. Thus, notably, the solution of the present disclosure results in higher yields.

[0351] Although reducing the chord reduces production and handling and transportation problems, it reduces the lay height of the blade structure near the root and therefore may, at first glance, lead to an increase in material in the root area of ​​the blade, which introduces bending moments. The tip typically harvests more energy per blade area unit than the blade area near the rotor center. Therefore, reducing the chord has a positive effect on the yield ratio to wind and snow loads and is therefore advantageous, saving material, for example, in the tower or foundation.

[0352] DESCRIPTION OF THE DRAWINGS FIG. 1 shows one embodiment of a land-based HAT 1 having a rotor 2 designed to minimize environmental disturbances, for example, by reducing noise and / or reducing cast shadows, while achieving a high cost-to-yield ratio. In this example, the rotor has a radius 3, seven blades 4, a tower 5, a nacelle 6, and a hub 7. Each blade has a length L8, a local chord 9, and a maximum chord 10. The direction in which the rotor rotates is indicated by arrow 11. The land-based turbine may be anchored to the ground 12 by any state-of-the-art foundation (not shown). An example of a cross section II is shown in FIGS. 16-18.

[0353] FIG. 2 shows one embodiment of an offshore HAT 21 with an upwind rotor 22 of diameter D33 having five blades 23. The rotor may be designed to minimize environmental disturbance, for example, by producing low noise and a low cast shadow, while achieving a high cost-to-yield ratio. The blades 23 may include a pultruded aerodynamic inner section 24, which in this example also has a maximum chord 29, a pultruded intermediate section 25, a pultruded outer section 26, and a tip 27. Sections of the blades 23 may be fabricated by injection molding, 3D printing, or any conventional method. The offshore turbine may be located on a tower 5 that traverses the seawater surface 30 and continues as a monopile foundation 32 anchored to the seabed 31. An example of cross section II-II is shown in FIGS. 14-15.

[0354] 3 illustrates an embodiment of a land-based HAT 41 with a relatively high blade count, having a rotor 42 designed to operate at a relatively low tip speed ratio λ. In this case, there are seven large blades 43 and seven short blades 44 on the same rotor 42. There may be one large blade and one small blade, as shown, with a pultruded inner section 45, a pultruded middle section 46, and a tip 47. In this example, the low tip speed ratio may further reduce the turbine noise level. The low tip speed and relatively high blade count may also reduce the likelihood of bird strikes.

[0355] 4 shows a graph of a conventional distribution 50 of local chord versus radial position, in one embodiment, and several limit lines for the local chord. In one embodiment, the local chord distribution of the blade is shown by limit lines 51, c limit = 5.5%R - 3.5 / 85 (r - 15%R), and the local chord can be above the limit line for a radial length of up to 5%R. All illustrated limit lines can be valid for r = 15%R ~ R. The other limit lines 52, 53, 54, 55, 56, 57, 58 can be calculated by the formula c limit =5%R-3 / 85(r-15%R), c limit =4.5%R-2.5 / 85(r-15%R), c limit =4%R-2.0 / 85(r-15%R), climit=3.5%R-1.5 / 85(r-15%R), c limit =3.0%R-1 / 85(r-15%R), c limit = 2.5%R - 0.5 / 85 (r - 15%R), and c limit = 2.0%R, respectively.

[0356] Similar to the embodiment described in FIG. r For r=15%R~R, 5.5%R-2.5 / 85 * In one embodiment, c r For r=15%R~R, 5%R-2.0 / 85 * In one embodiment, c r For r=15%R~R, 4.5%R-1.5 / 85 * In one embodiment, c r For r=15%R~R, 4%R-1.0 / 85 * In one embodiment, c r For r=15%R~R, 3.5%R-0.5 / 85 * It may be less than (r-15%R).

[0357] 5 shows another graph of a conventional distribution 60 of local chord versus radial position, and several limit lines for the local chord, in one embodiment. In one embodiment, the local chord distribution of the blade is shown by limit lines 61, c limit = 5.5%R - 4.0 / 85 (r - 15%R), and the local chord can be above the limit line for a radial length of up to 5%R. All illustrated limit lines can be valid for r = 15%R ~ R. The other limit lines 62, 63, 64, 65, 66, 67, 68, 69 can be calculated by the formula c limit =5.0%R-3.5 / 85(r-15%R), climit=4.5%R-3.0 / 85(r-15%R), c limit =4.0%R-2.5 / 85(r-15%R), c limit =3.5%R-2.0 / 85(r-15%R), c limit =3.0%R-1.5 / 85(r-15%R), c limit =2.5%R-1.0 / 85(r-15%R), c limit = 2.0%R - 0.5 / 85 (r - 15%R), and c limit = 1.5%R, respectively.

[0358] FIG. 6 illustrates an embodiment of a land-based HAT 91 having dual rotors 92. In this example, the dual rotors include a first rotor of radius R with seven blades 93 and a second rotor of radius R2 96 with three blades 97. The first rotor blades have a local chord 94 and a maximum chord 95. In this example, the first rotor blades, which face vertically upward, are shown with an inner pultrusion 100, an outer pultrusion 101, and a tip 102. The smaller rotor blades of the second rotor may be connected to a hub 98 and may rotate in a direction 99. The rotational speed of the second rotor, in use, is designed to be faster than the rotational speed of the first rotor. The first rotor may be any rotor for a HAT turbine. The second rotor may also be any conventional rotor for a HAT turbine.

[0359] In one embodiment, the second rotor may generate energy directly via a connection to a generator.

[0360] In one embodiment, the second rotor may be designed to rotate freely and not produce any useful torque, thus C P may be approximately 0. In one embodiment, the second rotor is designed to have an axial force coefficient in use greater than 0.6, preferably greater than 1.0, more preferably greater than 1.2, more preferably greater than 1.5, and preferably less than 2.2. In operation, the second rotor simply slows or even almost completely blocks the wind, forcing it around the swept area of ​​the second rotor and, in turn, the larger swept area of ​​the first rotor. The first rotor may be optimized for maximum energy capture in combination with the blocking characteristics of the second rotor. The second rotor may include a brake so that it can be stopped in the event of high wind speeds. This may reduce the load on the HAT. For example, when wind speeds increase, the HAT may be controlled as follows: At cut-in wind speed, both rotors may be started, with the first rotor generating energy and the second rotor rotating freely with an axial force coefficient greater than 0.6. As the HAT approaches its maximum power, the second rotor may be stopped using a brake. The second rotor no longer blocks the wind and directs it around the radial range between R2 and R of the first rotor, resulting in a reduction in the power of the first rotor. The wind can flow largely unimpeded through the swept region of the second rotor. Because the first rotor is still slowing the wind, it may increase airflow through the rotor center or swept region of the second rotor. At cutout wind speeds, the first rotor may also be stopped. This embodiment captures energy from the torque of the second rotor, providing the benefits of a dual-rotor system without the complexity of the drivetrain. In one embodiment, the number of blades on the second rotor need not be equal to the number of blades on the larger rotor, providing the benefit of reduced resonance and / or sound. Preferably, the number of blades on the second rotor may be three, and the number of blades on the first rotor may be at least five.

[0361] Both the first rotor and the second rotor may include pitch-controlled blades. The portion of the first rotor "covered" by the swept area of ​​the second rotor may be structurally optimized to minimize loads and retain only the portion of the blades not covered by the second rotor. Thus, the first rotor may have a much lower rigidity (r=R2) and therefore have lower wind loads and may be more easily controlled. The captured energy may be approximately equal even if the second rotor does not directly generate useful energy, because the first rotor harvests most of the energy of the wind flowing through the swept area of ​​the second rotor if the second rotor does not disrupt or even block the flow.

[0362] FIG. 7 shows an embodiment of a land-based HAT 111 with a rotor having stays 112. In this example, the rotor has seven blades 113 that may be connected to a hub 7. In this example, avgsol. 25R / avgsol. 75R and avgsol. 35R / avgsol. 75R may be approximately 1±30%. Bending moments on the blades may be efficiently channeled to the hub via one or more stays. In one embodiment, the blades may be interconnected with tangential stays 114. In one embodiment, each blade may be secured to the hub in a forward direction by stay 115. In one embodiment, each blade may be secured to the hub in a rearward direction by stay 116. Stays 115 and 116 may be radial stays. In one embodiment, the stays may converge at point 117 and be secured to the blades by stay holders. Such stay holders may be designed to control the blades' pitch over at least 30 degrees, preferably at least 60 degrees, and more preferably at least 90 degrees. An example of section III-III including a stay holder is shown in FIG. 8.

[0363] Figure 8 shows an example of cross section III-III of the blade 113 of Figure 7. Figure 8 shows the airfoil 131 in the working position. It is fixed to a stay holder 135 at a fixing point 132 so that it can rotate about a bearing 134 from the working position 131 to the vane position 133. The stay holder may be connected to the tangential stay 114, the forward stay 115, and the aft stay 116, and may include a shock absorber 136 to prevent damage to the blade.

[0364] Figure 9 shows an embodiment of an offshore HAT 151 with a large leeward three-bladed rotor 152. In this example, avgsol. 25R / avgsol. 75R and avgsol. 35R / avgsol. 75R may be approximately 0, assuming the truss structure is not aerodynamically shaped. The large rotor includes blades 154. One of the blades is shown interrupted at position 155 for illustrative purposes. In this example, the blade may include four differently sized pultruded sections 155, 156, 157, and 158 with progressively increasing chords from tip to root. The large rotor may have a truss structure with tangential rods or tangential connections 156, forward rods 157, and rods 160 extending along the length of the blade. The latter may be fixed to hub 7 at one end and to blade 154 at the other end. A pitch mechanism may be installed at connection point 159 or the hub and may drive the blade via rods 160. All rods may have aerodynamic shapes, and radial connections 160 and 157 in particular may be designed to contribute to aerodynamic lift. The rods may be compression elements that can be loaded in both compression and tension.

[0365] FIG. 10 shows another embodiment of an offshore HAT 151, this time including a three-bladed windward small rotor 153. The small rotor has blades 161 that can be made of one or more pultruded sections 162, 163, 164, 165, 166, and 167. The blades can be fixed to a second hub 168, on which a pitch mechanism and brakes can be located. The rotor 153 can be designed to contribute directly to the generated power through a mechanical link to a generator and, possibly, through gearing of the large rotor to the generator. In a non-limiting preferred embodiment, the small rotor simply serves to close the aerodynamic gap at the center of the large rotor by applying an axial force that blocks the wind. The small rotor can be designed to create a large blockage by free rotation. The wind is then directed around the small rotor toward the blades of the large rotor, thereby indirectly contributing to the generation of power via the large rotor. The small rotor can be equipped with a brake so that the small rotor can be stopped at a certain wind speed.

[0366] FIG. 11 shows an embodiment of a land-based HAT 181 with a rotor 182 having eleven blades 183. The blades may include two pultruded sections: an inner section 185 and an outer section 184. The turbine may be oriented into the wind by a large trailing vane 189. Such a trailing vane is particularly advantageous for small HATs. The HAT 181 may be designed with a relatively low tip speed ratio, e.g., 6, resulting in a low sound level and a low risk of bird strikes. The vane may be reinforced by a support structure 186 and typically has a large surface that may be divided into a fixed surface 190 and multiple smaller hinge surfaces 187. Each of the surfaces 187 may be secured to the support 186 by a hinge 188. The advantage of this design is that, at low wind speeds, the vanes are large enough to align the rotor with the wind, while at high wind speeds, the vanes do not exert high alignment forces on the HAT because the surface 187 hinges to a more horizontal position when the wind direction suddenly changes, thereby reducing the alignment force. This avoids high-speed yaw movements that would cause high gyroscopic tilt moments that would overload the HAT. Aligning the HAT with the trailing vanes in this embodiment has been found to be effective because the large vanes provide sufficient alignment forces to align the HAT at near-cut-in wind speeds. Furthermore, when the turbine operates at low speeds, e.g., 3-6 m / s, and the vanes are in the wake, the wind speed can be reduced to approximately one-third of the undisturbed wind speed due to rotor energy extraction, and the vanes have a sufficient cross-section to align the HAT with the wind. Advantageously, the large surface of such trailing vanes can also be suitable for advertising, e.g., logo placement.

[0367] FIG. 12 is an exemplary graph of the shadow cast by a conventional blade pass 191 and an embodiment blade pass 192 at a distance of approximately 2D. The y-axis is the ratio of light intensity in shadow to light intensity without shadow. The conventional blade pass reaches the core shadow when the intensity ratio is I / I0=0.1, which is equal to the indirect sunlight intensity ratio. The x-axis represents the position of the passing blade in units of 0.50 degrees of sunlight angle. In one embodiment, the blade cast shadow can be half width and half depth. The local chord of the conventional blade passing through the sun is approximately 10%R, while the local chord of the embodiment blade is approximately 3.5%R.

[0368] 13 shows an exemplary graph of the SPL variation caused by individual blade passes. Curve 194 is the variation for a conventional HAT, showing an amplitude of approximately 6 dB. In one embodiment, the number of blades in the HAT may be five, and the reduced amplitude modulation may follow curve 195. In another embodiment, the number of blades may be seven, and the amplitude modulation may nearly disappear, as shown by curve 196.

[0369] FIG. 14 shows an example of a pultruded twisted airfoil section 200 having a leading edge 202 and a trailing edge 203, and an example of a pultrusion 201 orientation that may be parallel to the blade longitudinal axis. The section terminates in a chord 205 corresponding to section II-II in FIG. 2. The chord 205 at one end may be twisted at an angle 207 relative to the chord 206 at the other end during the pultrusion process. The pultruded airfoil section may include voids 208, 209 that may be filled with separately produced structural elements 210 that may be stiffened within the void 208 over its length 211 to give the section greater bending stiffness over its length 211. For illustrative purposes, the void 208 is shown with a separately produced structural element on only one side of the void; in practice, structural elements may be stiffened on the opposite or other side of the void or other voids, and the structural elements may have different lengths.

[0370] FIG. 15 shows an example of a blade section 212 that is pultruded without twisting. Cuts 213, 214 may be made during or after pultrusion. The cuts may reduce the torsional stiffness of the section. Therefore, the section may be easily twisted after production and the cuts re-hardened to lock the blade section in the twisted position. A blade section produced in this manner may also be considered a pultruded twisted airfoil section. The pultruded airfoil section has a circular void 215, whereby a separately produced structural element, for example, in the shape of a reinforcing cylinder 216, may be installed in the circular void. The axis of the circular void may coincide with the torsional axis. The reinforcing cylinder may be installed along the length 217 of the pultruded airfoil section so that the stiffness of the combination varies along the blade length.

[0371] Figure 16 shows an example of a blade section 220 with optional indentations 221 and a cross section 222 corresponding to cross section II-II of Figure 1. As shown in Figure 16, the indentations 221 do not have to be part of a local chord. In one embodiment, the indentations may be made of a transparent flat plate to reduce cast shadows. Preferably, the surface of the indentations may be optically coated so that some of the reflected light is minimized.

[0372] 17 shows another example of a blade section 220 having an optional thin plate 203 attached to the trailing edge. The plate 203 may be made of a rigid material, such as a composite, and may protrude relative to the trailing edge 203 to provide a pointed extended trailing edge 223. The thickness of the extended trailing edge may be, for example, 0.5 mm or less. The thin plate may be transparent and / or optically coated to reduce cast shadows.

[0373] FIG. 18 shows an example of a blade section 230 with an optional pair of vortex generators 232 near the trailing edge. Each pair of vortex generators may have a base plate 239 and two fins 231, which may be designed to generate counter-rotating vortices. The distance between the pressure sides 233 of the fins may be fixed, while the distance between the suction sides 234 may be variable. In one embodiment, the vortex generators may be located near the trailing edge, for example, at a chord position greater than 60% c or even 80% c. Chord positions are counted from 0% c at the leading edge to 100% c at the trailing edge, with the reference for vortex generator location being the front of the fin. Vortex generators near the trailing edge serve to reduce boundary layer thickness, thereby reducing noise generated by the airfoil. The airfoil section may also have vortex generators located at approximately 20% c to 40% c. Here, vortex generator pairs 235, or vortex generators with separate fins 236 that may not be connected through a base plate, may be used. The advantage of the latter vortex generators is that both the distance between the pressure sides 237 and the distance between the suction sides 238 can be varied, and such vortex generators may be used at the trailing edge. This may result in higher aerodynamic efficiency and may require fewer vortex generator pairs. An example of cross section IV-IV is shown in FIG. 19.

[0374] FIG. 19 shows an example of an optimized vortex generator pair 232, as shown in FIG. 18, attached using tape 243 to an airfoil surface 241. In one embodiment, the fins 242 of the vortex generator pair do not extend perpendicular to the base plate 239, but instead have an angle 240 of at least 0.5 degrees, specifically at least 1 degree, more specifically at least 2 degrees, and preferably about 10-15 degrees. Advantages of the vortex generator pair 232 as shown in FIG. 19 include slightly higher performance, easier injection molding because a smaller base plate 239 can be applied and stapled, and the angle 240 allows the product to be more easily demolded in a two-part mold. In one embodiment, the fin thickness (247), measured at 95% (245) of the total fin height (246), is at least 0.5 mm, or at least 0.7 mm, or at least 1 mm, or at least 2 mm. In one embodiment, the edges of the vg-fins 244 may be rounded instead of sharp, which has the advantage of better erosion resistance, and rounded edges are less likely to cause damage when coming into contact with other objects, reducing the risk of injury to maintenance personnel or cutting rappelling ropes performing blade maintenance.

[0375] FIG. 20 illustrates another graph of a conventional distribution 250 of local chord versus radial position, and several boundary lines 251-258 for the local chord, in one embodiment. In one embodiment, the blade local chord distribution is shown by boundary lines 251, c limit = 5.0%R, and the local chord can be above the limit line for a radial length of up to 5%R. All illustrated limit lines can be valid for r = 15%R to R. The limit lines 251, 252, 253, 254, 255, 256, 257, and 258 are defined by the formula c limit =5.0%R,c limit = 4.5%R, c limit =4.0%R,c limit =3.5%R,c limit =3.0%R,c limit =2.5%R,c limit = 2.0%R, and c limit = 1.5%R, respectively.

[0376] FIG. 21 illustrates an embodiment of a land-based HAT 271 with a rotor 272 having five blades 273. In this example, each blade includes a pultruded torsional aerodynamic section extending over at least 60% R. Blades 273 may optionally be equipped with devices to increase lift coefficient, such as vortex generators and / or chord extensions and / or Gurney flaps. In the example of FIG. 21, tower 274 may include one or more pultruded sections 275 with carbon fiber present. An advantage of pultruded tower sections is that they can be lightweight yet rigid. As a result, the tower section can be relatively thin, which may reduce shadowing and visibility, thereby contributing to reduced environmental hazards. Another advantage of using pultruded tower sections is a slight increase in turbine yield due to a reduced impact on wind. Additionally, acoustic impacts from the blades traversing the pressure / velocity field around the tower section may be reduced. A further advantage of pultruded tower sections is that the weight of the tower can be reduced, especially at high altitudes, when the tower is tilted relative to the ground, for example for maintenance purposes. The same figure also shows the sun 276, which is only partially obscured and therefore casts a reduced shadow thanks to the thin blades 273.

[0377] FIG. 22 illustrates, in one embodiment, the composite string N r c r A conventional distribution 280 of radial position is shown, along with several limit lines 281-288 for the local composite chord. For example, in one embodiment, the local composite chord distribution of the blade is shown by limit line 281, N r c limit = 16.5%R. All illustrated limit lines may be valid for r = 15%R to R. Limit lines 282, 282, 283, 284, 285, 286, 287, 288 are r c limit =15.0%R,N r c limit =13.5%R,N r c limit =12.0%R,Nr c limit =10.5%R,N r c limit =9.0%R,N r c limit = 7.5%R, and N r c limit = 6.0%R, respectively. For example, if the HAT has a maximum rotor diameter of 200 m with seven blades reaching 0.9R, and the blades have a local chord of 2 m over their entire span, then Nc r =7×2m=14m corresponds to 14%R, and as a result, the design is below limit lines 181 and 282 and above limit lines 282-288.

[0378] FIG. 23 illustrates, in one embodiment, the composite string N r c r A conventional distribution 290 of radial position is shown, along with several limit lines 291-298 for the local composite chord. For example, in one embodiment, the local composite chord distribution of the blade is shown by limit line 291, N r c limit = 16.5%R - 10.5 / 85 (r - 15%R). All illustrated limit lines may be valid for r = 15%R to R. Other limit lines 292, 293, 294, 295, 296, 297, 298 are given by the formula N r c limit =15%R-9 / 85(r-15%R), N r c limit =13.5%R-7.5 / 85(r-15%R), N r c limit =12%R-6.0 / 85(r-15%R), N r c limit =10.5%R-4.5 / 85(r-15%R), N r c limit = 9.0%R - 3.0 / 85 (r - 15%R), and N r c limit = 7.5%R - 1.5 / 85 (r - 15%R), respectively.

[0379] FIG. 24 illustrates, in one embodiment, the composite string N r c rA conventional distribution 300 of radial position is shown, along with several limit lines 301-309 for the local composite chord. For example, in one embodiment, the local composite chord distribution of the blade is shown by limit lines 301, N r c limit = 16.5%R - 12 / 85 (r - 15%R). All illustrated limit lines may be valid for r = 15%R to R. Other limit lines 302, 303, 304, 305, 306, 307, 308 are given by the formula N r c limit =15%R-10.5 / 85(r-15%R), N r c limit =13.5%R-9.0 / 85(r-15%R), N r c limit =12%R-7.5 / 85(r-15%R), N r c limit =10.5%R-6.0 / 85(r-15%R), N r c limit =9.0%R-4.5 / 85(r-15%R), N r c limit = 7.5%R - 3.0 / 85 (r - 15%R), and N r c limit = 4.5%R, respectively. For example, if a HAT has a maximum rotor diameter of 200 m, and the rotor has five blades that reach 0.9R, and the blades have local chords that increase linearly from 1 m at R to 5 m at 0.15R, the local chord at 0.75R is found by linear interpolation, and Nc r =7×2m=14m corresponds to 14%R, and as a result, the design is below limit lines 181 and 282 and above limit lines 282-288.

[0380] The limit for composite strings is N r By increasing c r This suggests that the c r The limit of the composite string is a useful parameter since a reduction in leads in particular to a reduction in optical disturbances.

[0381] In the above exemplary embodiments, where a blade is described that includes one or more pultruded sections, it should be understood that the blade may alternatively be made as a single piece conventional blade, and vice versa.

[0382] In the above description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the practice of the disclosed technology. However, it will be apparent to one skilled in the art that embodiments of the disclosed technology may be practiced without some of these specific details.

[0383] Gustave Paul Corten, Master of Science in Nuclear Engineering and Doctor of Wind Turbine Aerodynamics, is the author, illustrator, and inventor of this disclosure. A contemplated name for a turbine according to the present invention may be AmiWind or Ami Wind Turbine or Preferred Wind Turbine or Corton Wind Turbine or C!N!C Wind Turbine, where C!N!C is an abbreviation for Corten no Noise no Cast shadow.

Claims

1. A HAT wind turbine (1, 21, 41, 91, 111, 151, 181) for generating electricity from wind, comprising a tower (5), a nacelle (6), a generator, and a rotor (2, 22, 42, 92, 112, 152, 182), the rotor being rotatable about its rotor axis by wind, the rotor having a rotor solidity ratio SOL of at most 0.

10. ｒｏｔｏｒ the rotor has a radius R(3); the rotor comprises N blades (4, 23, 43, 44, 93, 113, 154, 183) of at least 4, each extending to a radial position of at least 0.90R; The blade is positioned at a local chord c ｒ (9, 28, 94) distribution of the radial position r; The local chord c in the radial range r=15% R to R ｒ but, Less than 5.5% R Less than 5% R, Less than 4.5% R Less than 4% R, Less than 3% R, Less than 2% R, and HAT wind turbine, one of less than 1.5%R.

2. The rotor has an average radial solidity avgsol. in the radial range of 0.15R to 0.35R. ２５Ｒ and the average radial solidity avgsol. in the radial range of 0.65R to 0.85R. ７５Ｒ and the ratio avgsol. between these average radial solidities is ２５Ｒ / avgsol. ７５Ｒ but, Less than 1.75, Less than 1.50, Less than 1.25, Less than 1.00, Less than 0.90, less than 0.75, less than 0.50, and 2. The HAT of claim 1, wherein the HAT has a viscosity of 1000 psig or less than 0.

25.

3. The rotor has an average radial solidity avgsol. in the radial range of 0.25R to 0.45R. ３５Ｒ and the average radial solidity avgsol. in the radial range of 0.65R to 0.85R. ７５Ｒ and the ratio avgsol. between these average radial solidities is ３５Ｒ / avgsol. ７５Ｒ but, Less than 1.75, Less than 1.50, Less than 1.25, Less than 1.00, Less than 0.90, less than 0.75, less than 0.50, and 3. The HAT wind turbine of claim 1 or claim 2, wherein the ΔT is one of less than 0.

25.

4. The blade is positioned at a local chord c ｒ (9, 28, 94) versus radial position r, and the local chord c in the radial range r = 15% R to R ｒ but, Less than 9% R, Less than 8%R, Less than 7% R, Less than 5.5% R Less than 5% R, Less than 4.5% R Less than 4% R, Less than 3% R, Less than 2% R, and one of less than 1.5% R or 5.5%R-2.5 / 85 ＊ Less than (r-15%R), 5%R-2 / 85 ＊ Less than (r-15%R), 4.5%R-1.5 / 85 ＊ Less than (r-15%R), 4%R-1 / 85 ＊ less than (r-15%R), and less than 3.5%R−0.5 / 85*(r−15%R); or 5.5%R-3.5 / 85 ＊ Less than (r-15%R), 5%R-3 / 85 ＊ Less than (r-15%R), 4.5%R-2.5 / 85 ＊ Less than (r-15%R), 4%R-2 / 85 ＊ Less than (r-15%R), 3.5%R-1.5 / 85 ＊ Less than (r-15%R), 3%R-1 / 85 ＊ Less than (r-15%R), 2.5%R-0.5 / 85 ＊ less than (r-15%R), and one of less than 2% R or 5.5%R-4.0 / 85 ＊ Less than (r-15%R), 5%R-3.5 / 85 ＊ Less than (r-15%R), 4.5%R-3.0 / 85 ＊ Less than (r-15%R), 4%R-2.5 / 85 ＊ Less than (r-15%R), 3.5%R-2.0 / 85 ＊ Less than (r-15%R), 3%R-1.5 / 85 ＊ less than (r-15%R), and The HAT wind turbine according to any one of claims 1 to 3, wherein the R is one of less than 1.5%.

5. 5. The HAT wind turbine of claim 1, wherein the N blades are one of at least 3 blades, at least 4 blades, at least 5 blades, at least 7 blades, and at least 11 blades, and wherein the blades reach a radial position of at least one of 0.70R and 0.90R.

6. 6. The HAT wind turbine of claim 1, wherein the N blades are one of a maximum of 7 blades, a maximum of 11 blades, a maximum of 17 blades, and a maximum of 43 blades, and wherein the blades reach a radial position of at least one of 0.70R and 0.90R.

7. 7. The HAT wind turbine according to any one of claims 1 to 6, wherein the diameter D is one of at least 5m, at least 10m, at least 20m, at least 40m, at least 70m, at least 100m, at least 140m, at least 200m.

8. The HAT wind turbine according to any one of claims 1 to 7, wherein the diameter D is smaller than 40m and is one of at least 3m, at least 5m, at least 10m, at least 25m.

9. The rotor has a maximum power coefficient C of at least one of 0.35, 0.40, and 0.

45. Ｐ and in particular, the rotor is designed to have a maximum power coefficient C of at least one of 0.35, 0.40, and 0.

45. ＰＥ 9. The HAT wind turbine according to any one of claims 1 to 8, designed to have

10. The rotor has a maximum solidity SOL of at least one of 0.07, 0.05, 0.04, 0.035, and 0.

03. ｒｏｔｏｒ The HAT wind turbine according to any one of claims 1 to 9, configured so that

11. The average radial solidity of the rotor at r=0.25R is avgsol. ２５Ｒ is one of less than 0.06, less than 0.05, less than 0.04, and less than 0.03, and in particular avgsol. ２５Ｒ HAT wind turbine according to any one of claims 1 to 10, wherein refers to the largest rotor.

12. The rotor has a design tip speed ratio λ ｄｅｓｉｇｎ It consists of λ ｄｅｓｉｇｎ The HAT wind turbine according to any one of claims 1 to 11, wherein is one of: less than 9, less than 8, less than 7, less than 6, and less than 5.

13. the rotor comprises a first blade and a second blade, the first blade and the second blade having a tangential connection (114, 156) at a radial position R3; one of R3 > 0.20R, R3 > 0.30R, R3 > 0.40R, and R3 > 0.45R; and / or one of R3<0.80R, R3<0.70R; R3<0.60R, and R3<0.50R; and / or 13. The HAT wind turbine according to any one of claims 1 to 12, wherein one of 0.20R<R3<0.80R, 0.30R<R3<0.70R, and 0.40R<R3<0.60R.

14. 14. The HAT wind turbine according to any one of claims 1 to 13, further comprising stays (115, 116, 117) and stay holders (135), wherein the blades, the stays, and the stay holders are connected at radial positions between 0.25R and 0.65R, and the stay holders are pivotally connected to the blades at joints whereby the blades can be pitched around the joints through one of at least 30 degrees, at least 60 degrees, and at least 90 degrees.

15. 15. The HAT wind turbine of any one of claims 1 to 14, wherein a truss structure at the center of the rotor connects the blades to a hub, the truss structure comprising one of a blade joint, a hub joint, and a compression member and a stay, the blade joint being connected to the hub joint by two compression members (156, 157, 160) or by one compression member and one stay, in particular the blade joint of a first blade being connected to the blade joint of an adjacent second blade by a compression member or a stay.

16. 16. The HAT wind turbine according to any one of claims 1 to 15, wherein the blades are fixed to pitch bearings (159), said pitch bearings being located at one of the radial positions of more than 0.25R, more than 0.3R, more than 0.35R, more than 0.4R, more than 0.45R and less than 0.6R.

17. a first blade and a second blade, the first blade being part of a first rotor and reaching a radial position R, and the second blade being part of a second rotor and reaching a radial position R2; one of R2<0.70R, R2<0.60R, and R2<0.55R; and / or and / or one of R2 > 0.25R, R2 > 0.30R, R2 > 0.35R, and R2 > 0.40R.

17. The HAT wind turbine according to any one of claims 1 to 16, wherein one of 0.25R<R2<0.70R, 0.30R<R2<0.60R, 0.35R<R2<0.55R, and 0.40R<R2<0.55R.

18. The second rotor is designed to rotate freely and not generate useful torque, thereby Ｐ is approximately 0, and in use, the axial force coefficient C Ｄ，ａｘ and C Ｄ，ａｘ But C Ｄ，ａｘ >0.6, C Ｄ，ａｘ >1.0, C Ｄ，ａｘ >1.2, C Ｄ，ａｘ >1.5, C Ｄ，ａｘ 20. The HAT wind turbine of claim 19, wherein one of <2.

2.

19. 19. A HAT wind turbine according to any one of claims 1 to 18, comprising a blade, said blade comprising a pultruded aerodynamic profile having a length of one of at least 50%R, at least 60%R, at least 70%R, and at least 80%R, optionally said pultruded aerodynamic profile comprising a kink and / or a vortex generator and / or a Gurney flap.

20. D is greater than 3 m and less than 50 m, and further comprising a trailing vane surface (186, 187, 190) for aligning the rotor with the wind, the trailing vane surface being such that πR ２ / 10 or greater, πR ２ / 5 or greater, πR ２ / 2 or greater, 1 / 2D ２ Larger, 3 / 4D ２ Greater than, D ２ Greater than 1 1 / 2D ２ A HAT wind turbine according to any one of claims 1 to 19, wherein the rear vane surface (187) is one of the larger ones, in particular a part of the rear vane surface (187) is hinged.

21. The HAT wind turbine is an onshore turbine or an offshore turbine. The HAT wind turbine is parallel-connected or standalone. the HAT wind turbine has exactly one rotor, the HAT wind turbine has exactly one largest rotor of radius R and exactly one second coaxial rotor of radius R2; The HAT has two rotors that are coaxial and rotate in the same direction. The rotor may be upwind or downwind relative to the tower. The generator is a direct drive or gear type. the rotor has a ring-shaped structure extending radially to less than 20% R; The rotor does not have a ring-shaped structure. The generator uses superconductivity. The rotor drives a fluid conduction. the rotor comprises an airfoil having a relative thickness t / c of ​​30% or greater; the rotor comprises a cambered airfoil; the rotor is provided with vortex generators; The rotor has a design lift coefficient c of 1.5 or more. ｌ and 21. A HAT wind turbine according to any one of claims 1 to 20, wherein the rotor is one or more of: comprising blade sections with a weight percentage of carbon fibre of 10% or more.

22. The rotor is of the high-speed runner type, and λ ｄｅｓｉｇｎ The HAT wind turbine according to any one of claims 1 to 21, wherein is one of greater than 4, greater than 5 and greater than 6.

23. The maximum rotor is the composite chord N ｒ c ｒ (9, 28, 94) distribution of the composite string N in the radial range r=15% R to R ｒ c ｒ but, Less than 15.0% R, Less than 13.5% R, Less than 12.0% R, Less than 10.5% R, Less than 9.0%R, Less than 7.5% R, and one of less than 6.0% R; or 16.5%R-7.5 / 85 ＊ Less than (r-15%R), 15.0%R-6.0 / 85 ＊ Less than (r-15%R), 13.5%R-4.5 / 85 ＊ Less than (r-15%R), 12.0%R-3.0 / 85 ＊ less than (r-15%R), and 10.5%R-1.5 / 85 ＊ (r-15%R), or 16.5%R-10.5 / 85 ＊ Less than (r-15%R), 15.0%R-9.0 / 85 ＊ Less than (r-15%R), 13.5%R-7.5 / 85 ＊ Less than (r-15%R), 12.0%R-6.0 / 85 ＊ Less than (r-15%R), 10.5%R-4.5 / 85 ＊ Less than (r-15%R), 9.0%R-3.0 / 85 ＊ less than (r-15%R), and 7.5%R-1.5 / 85 ＊ (r-15%R), or 16.5%R-12.0 / 85 ＊ Less than (r-15%R), 15.0%R-10.5 / 85 ＊ Less than (r-15%R), 13.5%R-9.0 / 85 ＊ Less than (r-15%R), 12.0%R-7.5 / 85 ＊ Less than (r-15%R), 10.5%R-6.0 / 85 ＊ Less than (r-15%R), 9.0%R-4.5 / 85 ＊ Less than (r-15%R), 7.5%R-3.0 / 85 ＊ less than (r-15%R), and 6.5%R-1.5 / 85 ＊ The HAT wind turbine according to any one of claims 1 to 22, wherein the R is one of less than (r-15%R).

24. A blade (4, 23, 43, 44, 93, 113, 154, 183) for use in a rotor of a HAT wind turbine (1, 21, 41, 91, 111, 151, 181) for extracting useful power from wind, said blade being rotatable about a shaft of said HAT wind turbine by said wind, said blade having a local chord c Ｌ (9, 28, 94) The blade length position l has a distribution from L = 0 at the blade root to L = 100% at the blade tip, and the local chord c in the blade length range of l = 15% L to L Ｌ The value of Less than 5.5% L, Less than 5% L, Less than 4.5% L, Less than 4% L, Less than 3% L, Less than 2% L, and one of less than 1.5% L; or 5.5%L-2.5 / 85 ＊ (l-15%L) or less, 5%L-2 / 85 ＊ (l-15%L) or less, 4.5%L-1.5 / 85 ＊ (l-15%L) or less, 4%L-1.5 / 85 ＊ (l-15%L), and 3.5%L-0.5 / 85 ＊ (l-15%L), or 5.5%L-3.5 / 85 ＊ (l-15%L) or less, 5%L-3 / 85 ＊ (l-15%L) or less, 4.5%L-2.5 / 85 ＊ (l-15%L) or less, 4%L-2 / 85 ＊ (l-15%L) or less, 3.5% - 1.5 / 85 ＊ (l-15%L) or less, 3%L-1 / 85 ＊ (l-15%L), and 2.5%L-0.5 / 85 ＊ (l-15%L), or 5.5%L-4.0 / 85 ＊ (l-15%L) or less, 5%L-3.5 / 85 ＊ (l-15%L) or less, 4.5%L-3.0 / 85 ＊ (l-15%L) or less, 4%L-2.5 / 85 ＊ (l-15%L) or less, less than 3.5%L - 2.0 / 85 * (l - 15%L), and 3%L-1.5 / 85 ＊ A blade that is one of less than (l-15%L).

25. 25. A blade according to claim 24 from a single piece having a length of at least one of 40m, 60m, 80m, 100m.

26. 1. A method for adapting an existing HAT wind turbine, comprising: removing a rotor from the existing HAT wind turbine; Installing a new rotor such that the wind turbine is a wind turbine (1, 21, 41, 91, 111, 151, 181) according to any one of claims 1 to 25.

27. 26. A method for extracting useful power from wind using a HAT wind turbine according to any one of claims 1 to 25, comprising the steps of: causing the wind to rotate blades of the HAT wind turbine around a shaft; and converting torque from the rotor of the HAT wind turbine into electrical energy using the generator of the HAT wind turbine.

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