Axis-variable, contra-rotating wind turbine

Abstract

An axis-variable, contra-rotating wind turbine is disclosed. The axis-variable, contra-rotating wind turbine according to the present invention comprises: a tower; spline shafts horizontally connected to both upper sides of the tower; main rotors respectively coupled to the spline shafts on both sides so as to be axially movable and configured to contra-rotate to convert wind energy into mechanical energy; a main actuator having one end connected to the main rotors and the other end connected to the tower, and configured to move the main rotors on both sides in the axial direction of the spline shafts so as to adjust the distance between the main rotors; and a nacelle that converts mechanical energy transferred to the spline shafts into electrical energy, wherein the rotors are moved in the axial direction of the spline shafts by means of the main actuator to adjust the distance between the main rotors on both sides, such that the amount of generated power can be maximized.

Description

Axial variable-rotation wind turbine

[0001] The present invention relates to a variable-axis, counter-rotating wind turbine, and more specifically, to a variable-axis, counter-rotating wind turbine capable of maximizing power generation by adjusting the distance between main rotors on both sides.

[0002] As is well known, a wind turbine is a generator that generates electricity by rotating the main rotor with wind, and the main rotor shaft of the wind turbine is connected to the shaft of the generator.

[0003] In general, a wind turbine includes a main rotor that converts the kinetic energy of the wind into mechanical energy, a shaft that transmits the mechanical energy converted by the main rotor to a generator, a nacelle or generator that converts the power transmitted to the shaft into electricity, and a tower that structurally supports the above configuration.

[0004] Depending on the connection position of each component, wind turbines are broadly classified into horizontal wind turbines (Horzontal Axis Wind Turbine, HAWT, which is the most common type) that have a horizontal positional relationship between the main rotor and the nacelle and are supported by a tower, and vertical wind turbines (Vertical Axis Wind Turbine, VAWT) that have a vertical positional relationship between the main rotor and the nacelle.

[0005] And in the form of HAWT, a horizontal wind turbine positioned in the order of the main rotor-nacelle is called an upwind turbine, and a horizontal wind turbine positioned in the order of the nacelle-main rotor is called a downwind turbine.

[0006] Typically, a vertical wind turbine with a single main rotor, generator, and tower structure is known as the simplest form of a single main rotor turbine (Single Rotor Wind Turbine, SRWT).

[0007] Meanwhile, a dual main rotor wind turbine (DRWT) is a turbine that has two main rotors added on a coaxial line to produce more power and be more efficient than a SRWT.

[0008] The traditional type of DRWT is known to consist of one set of opposing turbines and one set of directional turbines.

[0009] Here, a wind turbine in which the rotation directions of the main rotor of the opposing turbine and the main rotor of the directional turbine are the same is called a corotating wind turbine (co-DRWT), and a wind turbine in which the rotation directions of the two main rotors are opposite is called a counterrotating-DRWT (counter-DRWT).

[0010] From a fluid dynamic perspective, this can be understood as a type of wake problem, as the main rotor located behind the wind operates in the wake of the main rotor located ahead of the wind. This is caused by the fluid dynamics of the rear main rotor, which are influenced by the flow characteristics of the wake. Research has shown that if properly utilized, this can produce more power than before. Specifically, the performance comparison between the SRWT and the CRWT (including the counter-DRWT) yields the following results.

[0011] According to Lucia-Andreea Mitulet, Gabriela Oprina, Rares-Andrei Chihaia, Sergiu Nicolaie, Adrian Nedelcu, and Mihail Popescu. "Wind Tunnel Testing for a New Experimental Model of Counterrotating Wind Turbine," DAAAM 2014, the differences in power generation between SRWT and CRWT are summarized in Table 1.

[0012]

[0013] Also, referring to BG Newman. "Multiple Actuator-Disc Theory for Wind Turbines," Journal of Wind Engineering and Industrial Aerodynamics, Vol. 24, 1986., the results of research using computational fluid dynamics (CFD) are summarized in Table 2 as follows.

[0014]

[0015] The effectiveness of these counter-rotating wind turbines (CRWT) has been studied by considerable engineering research.

[0016] Furthermore, Newman BG reported that the ideal efficiency of the Betts SRWT ideal wind turbine is 59%, while the ideal efficiency of the CRWT is 13% greater.

[0017] In addition, according to Riadh WY Habash, Voicu Groza, Yue Yang, Charles Blouin, and Pierre Guillemette, "Performance of a Contrarotating Small Wind Energy Converter," ISRN Mechanical Engineering, Vol. 2011, which summarized the results showing that co-DRWT and counter-DRWT have different characteristics from a fluid dynamics perspective, the results of a comparative study on co-rotation between main rotors and counter-rotation between main rotors are presented in Table 3.

[0018]

[0019] Co-DRWT and counter-DRWT or CRWT show significant differences in effectiveness. Therefore, counter-CRWT and CRWT should be considered the same type.

[0020] Here, the rotation direction between the main rotors appears to be the distinguishing factor affecting the CRWT performance or effectiveness, but a more in-depth study reveals that the following five factors are important factors affecting the CRWT, as shown in Oprina G., Chihaia RA, El-Leathey LA, Nicolaie S., Bbutanu CA, Voina A. "A Review on Counter-rotating Wind Turbines Development," Journal of Sustainable Energy, Vol. 7, No. 3, September 2016.

[0021] (1) generator

[0022] (2) Power transmission system (or transmission) from the main rotor to the generator

[0023] (3) Wing cross-section and shape (including degree of twist or pitch)

[0024] (4) Solidity ratio

[0025] (3) Diameter ratio between the front and rear rotors

[0026] (5) The distance between the two main rotors.

[0027] The fifth factor has become a subject of interest to many researchers.

[0028] For reference, Sung Nam Jung, Tae-Soo No, and Ki-Wahn Ryu. "Aerodynamic performance prediction of a 30 kW counter-rotating wind turbine system," Renewable Energy, Vol. 30, 2005. reported that there is a difference in power production depending on the distance between the two main rotors, and presented the difference in power production as shown in Table 4 below.

[0029]

[0030] Meanwhile, Yosua Heru Irawan, M. Agung Bramantya. "Numerical Simulation of The Effect of Axial Distance Between Two Rotors in Counter-Rotating Wind Turbines," 2016 2nd International Conference on Science and Technology-Computer (ICST) reported that the mechanical power generation behavior changes depending on the distance between the two main rotors, highlighting the importance of an appropriate axial distance between the two main rotors.

[0031] As described above, as the distance between the axes of the two main rotors increases, the cantilever problem (large deflection) that is unfavorable to the rotation axis occurs, making it difficult to apply in reality.

[0032] The present invention has been devised to solve the conventional problems described above, and an object of the present invention is to provide an axially variable counter-rotating wind turbine capable of maximizing power generation by adjusting the distance between the main rotors on both sides.

[0033] In order to achieve the above object, the present invention is a technical idea of ​​a variable-axis, counter-rotating wind turbine, comprising: a tower; spline shafts horizontally connected to both upper sides of the tower respectively; main rotors respectively coupled to the spline shafts on both sides so as to be axially movable and to counter-rotate to convert wind energy into mechanical energy; a main actuator having one end connected to the main rotor and the other end connected to the tower, and moving the main rotors on both sides in the axial direction of the spline shaft to adjust the distance between the main rotors on both sides; and a nacelle converting mechanical energy transmitted to the spline shaft into electrical energy.

[0034] The main rotor may include a main hub axially movably connected to the spline shaft, a plurality of blades radially connected from the center of the main hub and rotating to convert wind energy into mechanical energy, and a main bushing rotatably supporting the outer diameter of the main hub.

[0035] The above main actuator may include a main tube rotatably connected to the tower as a pivot, and a main plunger rotatably connected to the main tube and rotatably connected to the main bushing.

[0036] The present invention may further include a main buffer bushing coupled to the outer diameter of the main plunger, and a main buffer cylinder having one end rotatably connected to the main buffer bushing and the other end rotatably connected to the tower.

[0037] The present invention may further include a support rotor axially coupled to support the spline shafts on both sides, and a support actuator connected to the support rotor and the tower so as to move the support rotor in the axial direction of the spline shaft in conjunction with the main actuator.

[0038] The above support rotor may include a support hub that is axially movably coupled to the spline shaft, and a support bushing that rotatably supports the outer diameter of the support hub.

[0039] The above support actuator may include a support tube rotatably connected to the tower as a pivot, and a support plunger reciprocally connected to the support tube and rotatably connected to the support bushing.

[0040] According to the present invention implemented by the above-described solution, the rotor is moved in the axial direction of the spline shaft by the main actuator to adjust the distance between the main rotors on both sides, which has a very useful effect of maximizing the amount of power generated.

[0041] In addition, according to the present invention implemented with the above-described solution, there is a very useful effect of preventing deformation due to bending moment by supporting the spline shaft by the support rotor and the support actuator.

[0042] Figure 1 is a front view showing the overall shape according to an embodiment of the present invention;

[0043] Figure 2 is an enlarged view showing the right part of Figure 1.

[0044] Figure 3 is a side view viewed from the 'A' direction of Figure 2.

[0045] Fig. 4 is a cross-sectional view showing the BB line cross-section of Fig. 2.

[0046] Figure 5 is an operating diagram showing an operating state according to an embodiment of the present invention.

[0047] - Explanation of drawing symbols -

[0048] 100: Tower 200: Spline shaft

[0049] 300: Main rotor 400: Main cylinder

[0050] 500: Support rotor 600: Support cylinder

[0051] 700: Nacelle

[0052] Hereinafter, in order to fully understand the present invention, a preferred embodiment of the present invention will be described with reference to the attached drawings.

[0053] The embodiments of the present invention may be modified in various ways, and the scope of the present invention should not be construed as being limited to the embodiments detailed below. These embodiments are provided to more fully explain the present invention to those of ordinary skill in the art.

[0054] Accordingly, the shapes of components depicted in the drawings may be exaggerated to emphasize a clearer explanation, and it should be noted that in each drawing, the same components may be depicted with the same reference numerals.

[0055] A variable-axis, counter-rotating wind turbine according to an embodiment of the present invention comprises a tower (100), spline shafts (200) horizontally connected to both upper sides of the tower (100), main rotors (300) that are axially movably coupled to the spline shafts (200) on both sides and that counter-rotate to convert wind energy into mechanical energy, a main actuator that is connected at one end to the main rotor (300) and at the other end to the tower (100) and moves the main rotors (300) on both sides in the axial direction of the spline shaft (200) to adjust the distance between the main rotors (300) on both sides, and a nacelle (700) that converts mechanical energy transmitted to the spline shaft (200) into electrical energy.

[0056] The tower (100) is a structure that forms the skeleton of the present invention.

[0057] Referring to Fig. 1, the tower (100) is a structure built tall like a tower, and has a height of approximately 80 m or more.

[0058] A main bracket (110) is provided on both sides of the center of the tower (100) to rotatably support the other end of the main actuator, and a support bracket (120) is provided on the upper part to rotatably support the other end of the support actuator.

[0059] The spline shaft (200) is horizontally connected to each of the upper sides of the tower (100) and has the function of transmitting the mechanical energy of the main rotor (300) to the nacelle (700) and guiding the axial movement of the main rotor (300).

[0060] Referring to Fig. 1, the spline shaft (200) is formed horizontally and connected in a cantilever shape to the upper left and right sides of the tower (100). That is, one end of the spline shaft (200) is rotatably fixed to the upper part of the tower (100) by a shaft bracket (130), and the other end is in an unsupported state.

[0061] And a bevel gear (BG) is connected to one end of a spline shaft (200) fixed to a tower (100) to transmit mechanical energy to a nacelle (700).

[0062] Referring to FIG. 3, the spline shaft (200) is provided with a plurality of keys at equal intervals along the outer surface to rotate together with the main rotor (300) and guide the movement of the main rotor (300) in the axial direction.

[0063] The main rotor (300) is axially movably coupled to the spline shafts (200) on both sides and rotates in opposite directions to convert wind energy into mechanical energy.

[0064] Referring to FIGS. 1 and 2, the main rotor (300) includes a main hub (310) that is axially movably coupled to a spline shaft (200), a plurality of blades (320) that are radially connected from the center of the main hub (310) and rotate to convert wind energy into mechanical energy, and a main bushing (330) that rotatably supports the outer diameter of the main hub (310).

[0065] Referring to FIG. 3, a plurality of keyways are formed on the inner diameter of the main hub (310) to be coupled to the keys of the spline shaft (200), so that the main hub can rotate together with the spline shaft (200) and move in the axial direction of the spline shaft (200).

[0066] The blade (320) is radially connected to the outer end of the main hub (310) and rotates by wind energy, and this wind energy is converted into mechanical energy through the spline shaft (200). The inner end of the blade (320) is connected so as not to protrude in the inner diameter direction of the main hub (310) so as not to interfere when moving in the axial direction of the spline shaft (200).

[0067] The main bushing (330) supports the outer diameter of the main hub (310) so that the main hub (310) moves in the axial direction of the spline shaft (200) that rotates together with the blade (320). A main link (331) is provided on one side of the outer diameter of the main bushing (330) to which one end of the main actuator is connected.

[0068] The main actuator functions to adjust the distance between the main rotors (300) on both sides by moving the main rotors (300) on both sides in the axial direction of the spline shaft (200).

[0069] Referring to FIGS. 1 and 2, the main actuator is implemented as a hydraulic or pneumatic cylinder (hereinafter referred to as “main cylinder (400)”) that is rotatably connected at one end to the main bushing (330) of the main rotor (300) and at the other end to the main bracket (110) of the tower (100) to move the main rotor (300) in the axial direction of the spline shaft (200).

[0070] This main cylinder (400) includes a main tube (410) that is pivotally connected to a main bracket (110) and a main plunger (420) that is reciprocally connected to the main tube (410) and is rotatably connected to a main bushing (330) by a main link (331).

[0071] In addition, the main actuator further includes a main buffer bush (430) coupled to the outer diameter of the main plunger (420), and a main buffer cylinder (440) having one end rotatably connected to the main buffer bush (430) and the other end rotatably connected to the main bracket (110).

[0072] The main buffer bushing (430) and the main buffer cylinder (440) buffer the vibration generated when the main plunger (420) reciprocates, thereby inducing smooth movement of the main rotor (300) in the axial direction of the spline shaft (200).

[0073] Meanwhile, the present invention further includes a support rotor (500) that is axially movably coupled to support the spline shafts (200) on both sides, and a support actuator connected to the support rotor (500) and the tower (100) so as to move the support rotor (500) in conjunction with the main actuator.

[0074] Referring to FIGS. 1 and 2, the support rotor (500) includes a support hub (510) that is axially movably coupled to a spline shaft (200), and a support bushing (520) that rotatably supports the outer diameter of the support hub (510).

[0075] Referring to FIG. 4, a plurality of keyways are formed on the inner diameter of the support hub (510) to be coupled to the keys of the spline shaft (200), so that the support hub can rotate together with the spline shaft (200) and move in the axial direction of the spline shaft (200).

[0076] The support bushing (520) supports the outer diameter of the support hub (510) so that the support hub (510) moves in the axial direction of the spline shaft (200). A support link (521) is provided on one side of the outer diameter of the support bushing (520) to which one end of the main actuator is connected.

[0077] The support actuator functions to move the support rotor (500) in the axial direction of the spline shaft (200) in conjunction with the main actuator.

[0078] Referring to FIGS. 1 and 2, the support actuator is implemented as a hydraulic or pneumatic cylinder (hereinafter referred to as a “support cylinder (600)”) that is rotatably connected at one end to a support bushing (520) of a support rotor (500) and at the other end to a support bracket (120) of a tower (100) to move the support rotor (500) in the axial direction of the spline shaft (200).

[0079] This support cylinder (600) includes a support tube (610) that is pivotally connected to a support bracket (120), a support plunger (620) that is reciprocally connected to the support tube (610) and rotatably connected to a support bushing (520) by a support link (521).

[0080] In addition, the support actuator further includes a support buffer bushing (630) coupled to the outer diameter of the support plunger (620), and a support buffer cylinder (640) having one end rotatably connected to the support buffer bushing (630) and the other end rotatably connected to the support bracket (120).

[0081] The support buffer bushing (630) and the support buffer cylinder (640) buffer the vibration generated when the support plunger (620) reciprocates, thereby inducing smooth movement of the support rotor (500) in the axial direction of the spline shaft (200).

[0082] The nacelle (700) includes a generator that converts mechanical energy transmitted to the spline shaft (200) into electrical energy.

[0083] For example, the nacelle (700) may include a gearbox that accelerates and transmits mechanical energy of the spline shaft (200), and a generator that converts the mechanical energy accelerated by the gearbox into electrical energy.

[0084] Since this nacelle (700) can be replaced from the above-described conventional technology, detailed descriptions are omitted.

[0085] The operation of the embodiment of the present invention configured as described above will be described in detail with reference to the attached drawings as follows.

[0086] First, it is assumed that the distance between the two main rotors (300) is adjusted in consideration of the power generation amount and wind speed.

[0087] First, the main cylinder (400) is driven to widen or narrow the distance between the two main rotors (300).

[0088] Then, the main plunger (420) moves inwardly of the main tube (410) to move the main bushing (330) toward the tower (100) as shown in FIG. 1, or moves outwardly of the main tube (410) to move the main bushing (330) toward the outside of the spline shaft (200) as shown in FIG. 5.

[0089] At this time, since the main hub (310) is rotatably supported by the main bushing (330), even if the blade (320) and the spline shaft (200) rotate, it moves in the axial direction of the spline shaft (200) without any interference.

[0090] In addition, the support cylinder (600) is also linked to move the support rotor (500) in the direction of the tower (100) or the outer direction of the spline shaft (200), so that the spline shaft (200) can be prevented from being deformed due to bending moment.

[0091] According to the embodiment of the present invention described above, there is an advantage in that the amount of power generated can be maximized because the rotor is moved in the axial direction of the spline shaft (200) by the main actuator to adjust the distance between the main rotors (300) on both sides.

[0092] In addition, according to the embodiment of the present invention described above, since the spline shaft (200) is supported by the support rotor (500) and the support actuator, there is an advantage in that deformation due to bending moment can be prevented.

[0093] The embodiments of the present invention described above are merely exemplary, and those skilled in the art to which the present invention pertains will readily appreciate that various modifications and equivalent other embodiments are possible.

[0094] Therefore, it can be well understood that the present invention is not limited to the forms mentioned in the detailed description above.

[0095] Accordingly, the true technical protection scope of the present invention should be determined by the technical idea of ​​the appended claims, and the present invention should be understood to include the technical idea defined by the appended claims and all modifications, equivalents, and substitutes within the scope thereof.

Claims

1. In a variable-axis, counter-rotating wind turbine, tower; Spline shafts connected horizontally to each side of the upper portion of the tower; A main rotor that is axially movably coupled to the spline shafts on both sides and rotates counter-rotatably to convert wind energy into mechanical energy; A main actuator, which is connected at one end to the main rotor and at the other end to the tower, moves the main rotors on both sides in the axial direction of the spline shaft to adjust the distance between the main rotors on both sides; and A variable-axis, counter-rotating wind turbine, characterized in that it includes a nacelle that converts mechanical energy transmitted to the spline shaft into electrical energy.

2. In claim 1, The above main rotor is, A main hub axially movably coupled to the spline shaft; A plurality of blades that are radially connected from the center of the main hub and rotate to convert wind energy into mechanical energy; and A variable-axis, counter-rotating wind turbine, characterized by including a main bushing that rotatably supports the outer diameter of the main hub.

3. In claim 2, The above main actuator is, A main tube pivotally connected to the above tower; and A variable-axis, counter-rotating wind turbine, characterized in that it includes a main plunger that is reciprocally connected to the main tube and rotatably connected to the main bushing.

4. In claim 3, A main buffer bushing coupled to the outer diameter of the above main plunger; and A variable-axis, counter-rotating wind turbine, characterized in that it further includes a main buffer cylinder, one end of which is rotatably connected to the main buffer bush and the other end of which is rotatably connected to the tower.

5. In claim 1, Support rotors each axially movably coupled to support the above-mentioned spline shafts; and A variable-axis, counter-rotating wind turbine, characterized in that it further includes a support actuator connected to the support rotor and the tower so as to move the support rotor in the axial direction of the spline shaft in conjunction with the main actuator.

6. In claim 5, The above support rotor is, A support hub axially movably connected to the spline shaft; and A variable-axis, counter-rotating wind turbine, characterized by including a support bushing that rotatably supports the outer diameter of the support hub.

7. In claim 6, The above support actuator, A support tube pivotally connected to the above tower; and A variable-axis, counter-rotating wind turbine, characterized by including a support plunger that is reciprocally connected to the support tube and rotatably connected to the support bushing.

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