CN111133192A

CN111133192A - Wind turbine

Info

Publication number: CN111133192A
Application number: CN201880061744.0A
Authority: CN
Inventors: 尹瑨穆
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-07-21
Filing date: 2018-07-23
Publication date: 2020-05-08
Also published as: JP2020528514A; KR102185806B1; KR20190010505A

Abstract

A wind turbine is provided, comprising: a rotating part; a nacelle assembly in which a main shaft for increasing rotational kinetic energy of the rotating portion is mounted; a power transmission shaft connected perpendicular to the main shaft to transmit rotational kinetic energy of the rotating part; a tower supporting the nacelle assembly and having a power transmission shaft mounted in a tower section; and a power generation unit to which rotational kinetic energy is transmitted through the power transmission shaft. In the wind turbine of the present invention, the driving torque of the power transmission shaft and the reaction torque of the nacelle assembly are compensated for each other by the electromagnetic force generated between the rotor of the power generation unit receiving the driving torque and the stator of the power generation unit receiving the reaction torque according to lenz's law.

Description

Wind turbine

Technical Field

The present invention relates to a wind turbine in which a generator coupled with a nacelle assembly is installed in a lower portion of a wind turbine installation tower, and more particularly, to a wind turbine having a reaction torque balancing mechanism that balances reaction torque generated in the nacelle assembly by using electromagnetic force generated by the generator.

Background

Generally, a rotating blade wind turbine includes: a rotating part for converting wind power into mechanical rotational kinetic energy; a nacelle assembly comprising means for converting rotational kinetic energy of the rotating portion into electrical energy; and a tower for supporting the nacelle assembly. Wind turbines are classified into vertical axis type wind turbines and horizontal axis type wind turbines according to whether the rotation axis of the blades is horizontal or vertical with respect to the ground, and the vertical axis type wind turbines operate regardless of the wind direction, but have disadvantages in that the start-up of the wind turbines is not easy and unstable or the power generation efficiency is low.

A rotating part of a typical horizontal axis type wind turbine includes a hub nose cone assembly in which a plurality of blades arranged at regular intervals in a radial direction are assembled, wherein the hub nose cone assembly is connected to a horizontal main shaft installed in a machine gun assembly, and the hub nose cone assembly rotates with the blades rotated by wind power in a state in which a generator is assembled on the main shaft, and a rotational force is transmitted to the main shaft to drive the generator to generate electric power.

A conventional horizontal axis wind turbine has the following structure: in which important devices including a heavy generator are installed inside a nacelle assembly disposed on an upper end of a tower, and thus, construction, installation, inspection, maintenance and repair work of a conventional horizontal axis type wind turbine is difficult, and construction costs are increased as manufacturing costs are increased, costs of electricity production are high, and importance of anti-seismic design for a heavy power generation unit supported in the air and the nacelle assembly is increased.

Korean patent No.10-1027055 (3/29/2011) of the applicant discloses a wind turbine which is intended to simplify the structure of a nacelle assembly and reduce construction costs by reducing the total weight of the wind turbine, wherein kinetic energy of a rotating part is rapidly increased at a main shaft of the nacelle assembly and is transmitted to a generator positioned on the ground below a tower via a power transmission shaft vertically coupled with the main shaft of the nacelle assembly by adopting the following structure: this mechanism is used to balance the reaction torque generated by the load operating the generator by means of the upper and lower yoke mechanisms of the vertical power transmission shaft of the inventive mechanical structure for free yaw of the nacelle assembly.

However, the wind turbine disclosed in the above-mentioned prior art has the following problems: the problem of heavy weight of the reaction torque balancing mechanism of the yoke mechanism adopting a mechanical structure operating in a vertically reciprocating motion, and the problem of up-and-down vibration of the thrust bearing capable of freely yawing the nacelle assembly by converting the motion into a rotational operation while reciprocating up and down with the yoke mechanism, thereby complicating the production process and increasing the manufacturing and maintenance costs.

Disclosure of Invention

Technical problem

Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide a wind turbine in which reaction torque is balanced by using electromagnetic force induced under lenz's law (h.f.e.lenz, russian physicist, germany).

Another object of the present invention is to provide a wind turbine with a reaction torque balancing mechanism that facilitates the handling and transportation of a vertical power transmission shaft, a generator, etc., and prevents vibration of a yoke mechanism during the operation of mounting the generator.

Technical scheme

The object of the invention is achieved by providing a wind turbine comprising:

a rotating part having a main shaft for converting wind power into mechanical rotational kinetic energy, the rotating part being horizontally installed with respect to a ground;

a nacelle assembly in which the main shaft of the rotating part is mounted,

a power transmission shaft vertically connected to a main shaft of the nacelle assembly through gear engagement, to which rotational kinetic energy of the rotating portion is transmitted;

a hollow shaft unit having an upper end connected to a bottom of the nacelle assembly and a lower end extending downward;

a tower including a tower body having an upper portion connected to a hollow shaft unit through a pair of up-down yaw bearings and a lower end fixed to a support base, wherein a power transmission shaft is provided in the hollow shaft unit; and

a generator, comprising: a housing, a multi-pole rotor having a shaft and a plurality of stators spaced apart from the rotor, wherein the housing couples and fixes a lower end of the hollow shaft unit in the tower and thus is mounted on the hollow shaft unit in a floating manner, and the shaft of the rotor is coupled to a power transmission shaft through a coupling such that electric energy is generated by rotational kinetic energy transmitted via the power transmission shaft, wherein a reaction torque of the nacelle assembly transmitted to the stator of the generator is balanced by a driving torque generated by an electromagnetic force due to a rotational magnetic field of the rotor under lenz's law.

According to one aspect of the invention, a wind turbine may comprise a rotating base assembly having a structure to rotatably support a spindle coupled coaxially with a rotor shaft of a generator on a support base in a mounted position of the generator.

According to another aspect of the invention, the inventive wind turbine comprises a hollow shaft unit and a power transmission shaft, which are vertically built in multiple parts or made of multiple halves, sections or parts by using connecting means for constituting the multi-stage body of the hollow shaft unit and the power transmission shaft, respectively.

According to another aspect of the invention, the inventive wind turbine further comprises a reaction torque transfer mechanism comprising a reaction torque transfer shaft rotatably arranged between the nacelle ring gear of the hollow shaft unit and the ring gear of the rotating base assembly.

According to another aspect of the invention, the inventive wind turbine comprises a parallel drive mechanism comprising: a housing having a bearing housing coupled to the power transmission shaft and to a lower portion of the hollow shaft unit; a main gear attached to a lower end of the power transmission shaft through the bearing housing; a plurality of sub-gears axially coupled to a lower portion of the housing at a predetermined angle to be respectively engaged with the main gear; and a plurality of generators axially coupled to each of the shafts of the sub-gears.

According to another aspect of the invention, the inventive wind turbine comprises a horizontal generator mechanism comprising: a housing formed with a bearing housing coupled to the power transmission shaft and disposed between a lower end of the hollow shaft unit and the rotating base assembly; a first bevel gear attached to a lower portion of the power transmission shaft exposed to pass through the housing; a second bevel gear engaged with the first bevel gear; and a generator having an end of a horizontal rotor shaft coupled to the second bevel gear.

According to another aspect of the invention, the inventive wind turbine may comprise a pitch control mechanism comprising: a push-pull rod disposed through a longitudinal hollow in the hollow main shaft of the nacelle assembly; a connecting rod and an actuator respectively coupled to either one of the two ends of the push-pull rod; a plurality of pivoting joint pins sequentially connected to the rotating blades such that the blades form a predetermined angle with a central axis of the hub, and such that a control position of the pivoting joint pin installed in the hub is changed as the angle is changed.

Advantageous effects

In the wind turbine according to the present invention, in which rotational kinetic energy of the rotating part is transmitted to the generator coupled to the lower end of the hollow shaft unit attached to the lower portion of the nacelle assembly through the power transmission shaft vertically installed in the tower, when the gears connected to the power transmission gears, which receive the power generation load (energy of the generator against power generation) of the generator, are rotated by the main gear of the nacelle assembly, rotational force is applied to the power transmission shaft and the main gear receives reaction force against the rotational force at the contact point (moment equivalent average point) or the force point of the two gears, thereby generating rotational torque or reaction torque in a direction perpendicular to the reaction force due to the distance between the force point and the rotational axis of the gear coupled to the power transmission shaft. However, the reaction torque for rotating the nacelle assembly is balanced by using the electromagnetic force generated in the generator, thereby achieving free yaw of the nacelle assembly and simplifying the structure of the nacelle assembly, and reducing the weight of the wind turbine and the construction costs thereof.

Drawings

Other advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which like or similar reference characters designate the same elements, and in which,

figure 1 is a schematic cross-sectional view showing the configuration of a wind turbine according to a first embodiment of the present invention,

fig. 2a is a cross-sectional view taken along line a-a' in fig. 1, while fig. 2b is a conceptual diagram illustrating the reaction torque received by the nacelle assembly,

fig. 3a and 3b are a partial detailed view showing the internal construction of the generator in fig. 1 and a cross-sectional view taken along the line b-b' in fig. 1,

figure 4 is a schematic cross-sectional view of a wind turbine with a reaction torque balancing mechanism according to a second embodiment of the present invention,

figures 5 to 7 are cross-sectional views taken along the lines c-c ', d-d ' and e-e ' in figure 4 respectively,

FIG. 8a is a schematic cross-sectional view of a wind turbine according to a third embodiment of the invention, FIG. 8b is a cross-sectional view taken along the line f-f' in FIG. 8a,

fig. 9a is a schematic cross-sectional view of a wind turbine according to a fourth embodiment of the invention, and fig. 9b is a cross-sectional view taken along the line g-g' in fig. 9a,

fig. 10a is a schematic cross-sectional view of a wind turbine according to a fifth embodiment of the invention, and fig. 10b is a cross-sectional view taken along the line h-h' in fig. 10a,

FIG. 11a is a schematic cross-sectional view of a wind turbine of a sixth embodiment of the invention, and FIG. 11b is a cross-sectional view taken along the line i-i' in FIG. 11a, an

Fig. 12a to 12b are schematic views showing the configuration of a pitch control mechanism of a wind turbine having a reaction torque balancing mechanism according to a seventh embodiment of the present invention.

Detailed Description

Hereinafter, the present invention will be described in detail with reference to embodiments thereof and the accompanying drawings. Like reference numerals refer to like elements throughout the drawings.

Fig. 1 shows a configuration of a wind turbine according to a first embodiment of the invention, fig. 2a shows a cross section taken along line a-a' of fig. 1, and fig. 2b is a view showing the reaction torque received by the nacelle assembly.

Referring to fig. 1, 2a and 2b, in a wind turbine according to a first embodiment of the present invention, a tower 100, a nacelle assembly 200 and a rotating part 300 are sequentially assembled, and an adapter unit 160 is provided on an outer surface of a hollow shaft unit 120 in the tower 100, the adapter unit 160 having a bearing assembly for free yaw, and a lower portion of the nacelle assembly 200 and an upper end of the tower 100 are coupled to the hollow shaft unit 120.

In the wind turbine according to the first embodiment of the present invention, the free yaw of the nacelle assembly 200 is achieved by the adapter unit 160 provided on the hollow shaft unit 120 in the tower 100 without the aid of a separate yaw device, thereby allowing the nacelle assembly 200 to be operated only with the resistance of the wind received by the blades 310.

The nacelle assembly 200 includes a rotatable main shaft 220 horizontally supported on a support frame having a bearing therein, and a bevel gear 230 mounted on the main shaft 220, and the rotating part 300 includes a hub 320 and a plurality of blades 310, the hub 320 being attached to one end of the main shaft 220 of the nacelle assembly 200, and the plurality of blades 310 being attached to the hub 320 at a predetermined angle such that the main shaft 220 rotates with the rotation of the blades 310 in the wind. A stopper 240 is attached to the other end of the main shaft 220.

In the tower 100, there are provided a hollow shaft unit 120, a power transmission shaft 140, an adapter unit 160, and a tower body 180, wherein the hollow shaft unit 120 is fixed to a lower portion of the nacelle assembly 200, the power transmission shaft 140 has a bevel gear 142 on an upper end thereof to be combined with a bevel gear 230 of the nacelle assembly 200, and the power transmission shaft 140 is vertically installed in a bearing assembly 102 in the hollow shaft unit 120, the adapter unit 160 is installed on an outer surface of the hollow shaft unit 120, and the tower body 180 supports the lower portion of the adapter unit 160.

Since the bevel gear 142 of the power transmission shaft 140 is engaged with the bevel gear 230 of the main shaft 220, the rotational force of the main shaft 220 is transmitted to the power transmission shaft 140.

The adapter unit 160 includes an inner adapter 164 and an outer adapter 166, the inner adapter 164 and the outer adapter 166 having a pair of yaw bearings 162 therein to be mounted on the outer surface of the hollow shaft unit 120, and the upper yaw bearings are disposed between the protrusions 122 on the upper portion of the outer surface of the hollow shaft unit 120 and the outer adapter 166, in the drawing, the inner adapter 164 is positioned at an upper position, and the outer adapter 166 is positioned at a lower position, but they may be positioned at opposite positions.

A plate flange 602 is provided at a lower portion of the hollow shaft unit 120 to mount the generator 600.

The generator 600 includes a rotor shaft 610, a rotor 620, and a pair of

stators

630 and 635, the rotor shaft 610 being fixed to a lower end of the power transmission shaft 140 via a coupling 604, the rotor 620 being coupled to the rotor shaft 610, and the pair of

stators

630 and 635 being located spaced apart from an outer surface of the rotor 620. The case 640 is provided to surround the outer surfaces of the

stators

630 and 635, and bearings are provided at the lower and upper portions of the rotor shaft 610.

The tower body 180 is assembled on a support base 182 (hereinafter referred to as support base) that is installed into a support base region 184 of the installation site.

As described above with reference to fig. 1 and 2, in the free yaw wind turbine according to the first embodiment of the present invention, as the blades 310 rotate by the wind, the blades 310 and the main shaft 220 rotate, the rotational force of the main shaft 220 is transmitted to the power transmission shaft 140, and the rotational force transmitted to the power transmission shaft 140 is transmitted to the rotor shaft 610 of the generator 600.

Fig. 3a and 3b are an internal configuration of the generator and a cross-sectional view taken along line b-b' of fig. 1, respectively.

Referring to fig. 1, 2 and 3, the wind turbine according to the first embodiment of the present invention balances the reaction torque by using the electromagnetic force of the generator, as discussed below.

When the bevel gear 230 drives the bevel gear 142 of the power transmission shaft 140 with a force in the direction of the arrow Fc by the rotation torque H to receive the power generation load, a reaction torque D of the power transmission shaft 140 in the direction of the arrow D with respect to the rotation axis of the power transmission shaft, which rotates the nacelle assembly 200, is generated by a reaction force Fd that is received due to the force Fc and transmitted to the housing 640 and the

stators

630 and 635 fixed to the housing 640 of the generator 600 through the hollow shaft unit 120 to which the generator 600 is coupled.

When the bevel gear 230 of the main shaft 220 is operated to rotate the rotor 620 of the generator 600 through the bevel gear 142 engaged with the bevel gear 230, the coupling 604, and the power transmission shaft 140 engaged with the bevel gear 142 to receive a power generation load and thus the rotor 620 is rotated in the direction of the arrow C through the power transmission shaft 610, a rotating magnetic field is generated by the rotor 620 having magnets with N and S poles on opposite sides, and an electromagnetic force is generated according to lenz' S law, which is applied to the power generation coils 632 and 634 provided on opposite sides of the

stators

630 and 635. Due to the electromagnetic force induced as above, a magnetic force of polarity N is induced in the stator 630 and its generating coil 632 positioned in the direction in which the N pole of the rotor 620 travels, thereby hindering the movement of the rotor 620 by a repulsive force to the N pole of the rotor 620 and an attractive force to the S pole of the rotor 620, and a magnetic force of polarity S is induced in the stator 635 and its generating coil 634, which applies a repulsive force to the S pole of the rotor 620 and an attractive force to the N pole of the rotor 620. Torque in the direction of arrow U is generated to rotor 620 by force caused by

stators

630 and 635 in the direction of arrow T and transmitted as a power transmission load to power transmission shaft 140, while

stators

630 and 635 fixed in housing 640 as an integral part of housing 640 receive reaction torque D of nacelle assembly 200, which is transmitted to housing 640 via hollow shaft unit 120, and drive torque, which is generated by repulsive and attractive forces of rotor 620 in the direction of arrow V, which is the same as the direction of rotation of rotor 620. As a result, the

stators

630 and 635, which are a single body, receive two torques from opposite directions, i.e., the reaction torque D via the hollow shaft unit 120 and the driving torque V generated according to lenz's law at the

stators

630 and 635, so that the vector combination of the two torques is zero, i.e., U + V-U-0 (zero), and the reaction torque and the driving torque are balanced with each other, so that the generator 600 under the tower can be operated without the nacelle assembly 200 rotating due to the reaction torque.

The reaction torque balancing mechanism in the generator has been described for a generator including a rotor 620 having two magnetic poles and two

stators

630 and 635 having two magnetic poles, respectively, but it is the same for various generators including more than one rotor 620 and more than two

stators

630 and 635 having more than two magnetic poles, respectively, to balance the two torques with each other by electromagnetic force as long as a rotating magnetic field is utilized and applied to a generator including the rotor 620 provided with a coil and the two

stators

630 and 635 having a magnet.

Furthermore, the combination of the hollow shaft unit and the tower body may use other known configurations as long as the nacelle assembly can be freely yawed.

In addition, since the nacelle assembly 200 is supported by the hollow shaft unit 120 having a smaller diameter than the tower body 180, a surface area of the wind turbine exposed to the wind blows in a direction toward the rotating part 300, thereby reducing low frequency noise generated between the hollow shaft unit 120 and the blades 310.

Fig. 4 shows a configuration of a wind turbine according to a second embodiment of the present invention, and fig. 5 to 7 show cross-sections taken along lines c-c ', d-d ', and e-e ' of fig. 4, respectively.

Referring to fig. 4 to 7, the wind turbine according to the second embodiment of the present invention further includes a rotating base assembly 700, but other components are the same as those of the wind turbine of the first embodiment of the present invention described above, and thus the rotating base assembly 700 will be described with respect to the present embodiment.

The rotating base assembly 700 comprises a plate 710 attached to a lower portion of a housing 640 of the generator 600, a turntable 720, a base plate 730, and a thrust bearing 740, the turntable 720 being for receiving a rotor shaft 610 of the generator 600, the base plate 730 being mounted on a base or ground of the support base 182, the thrust bearing 740 being arranged between the turntable 720 and the base plate 730.

A spindle 722 coaxial with the rotor shaft 610 is inserted into the hollow portion of the turntable 720 and a spindle support portion 732 and fixed by a clamp nut 728 to support the generator 600, and a thrust bearing 724 and a radial bearing 726 are provided on the spindle 722 and in the hollow portion of the turntable.

The rotating base assembly 700 may have a structure different from the above-described structure as long as the spindle 722 coaxially connected to the rotor shaft 610 of the generator 600 is rotatably supported on the support base of the generator 600.

The rotating base assembly 700 in this embodiment can support the very large weight of the generator 600 so that it can easily pivot on the thrust bearing 740.

Fig. 8a shows a configuration of a wind turbine according to a third embodiment of the invention, and fig. 8a shows a cross-section taken along the line f-f' of fig. 8 a.

Referring to fig. 8, the wind turbine according to the third embodiment of the present invention further includes a coupling device 800, the coupling device 800 includes two halves of an additional hollow shaft unit 820 and a connector 860 for a power transmission shaft and other components for forming a lower portion of the power transmission shaft 140 and a hollow shaft unit below the yaw bearing 162 in its multiple halves or portions, and the other components are the same as those of the above-described first embodiment of the present invention, and thus the coupling device 800 may have a multi-stage connection structure.

The additional hollow shaft unit 820 is formed of first and

second halves

822, 824 thereof, the first and

second halves

822, 824 being coupled above and below the connector 860 for power transmission shafts and other parts, respectively. The first half 822 of the additional hollow shaft unit is fixed to the lower end of the hollow shaft unit 120 and is fixed on the connector 860 for the power transmission shaft and the second half 824 of the additional hollow shaft unit by means of a spline coupling as shown in fig. 1 for absorbing length changes caused by temperature changes of the

hollow shaft units

120 and 820 and the power transmission shaft 140, which is equally applicable to the insertion coupling of the power transmission shaft 140 into the power transmission shaft receiving support 826, and the spline coupling may be replaced with other known coupling means. In other figures, the component with reference numeral 826 is shown with an insert for receiving a power transmission shaft, and the generator 600 is fixed to the lowest part of the second half 824 of the additional hollow shaft unit.

The connector for the power transmission shaft comprises an inner bearing mount 862 arranged coaxially with the power transmission shaft receiving support 826 of the first half 822 of the additional hollow shaft unit, an outer bearing mount 864 arranged around the inner bearing mount 862, two pairs of bearings 670 arranged between the inner and outer bearing mounts 862, 864 respectively, and on the outer surface of the outer bearing mount 864, and a circular rim portion 866 having three projections equally spaced from the outer circumference of the outer bearing mount 864 and attached to the inside of the tower body 180.

Although the rim portion 866 has been described as having three projections, the number of projections may be four or more, and known mechanical elements may be used instead of the rim portion to fix the assembly with the bearing mount and bearing to the inside of the additional hollow shaft unit.

By dividing the power transmission shaft 140 into a plurality of parts by means of the coupling device 800, which may have a multistage structure, it is possible to prevent or reduce vibration caused by rotation of the power transmission shaft as a whole, because the power transmission shaft 140 includes an upper part above the yaw bearing 162 and the remaining lower part whose length is shortened, and can be built up in stages, thereby making it possible to reduce the cycle time and cost of construction of the wind turbine.

Fig. 9a and 9b show a configuration of a wind turbine according to a fourth embodiment of the invention and a cross-section along line g-g' of fig. 9a, respectively.

Referring to fig. 9, the wind turbine according to the fourth embodiment of the present invention further includes a separate reaction torque transmission mechanism for transmitting reaction torque, which is disposed between the lower end of the hollow shaft unit and the rotating base assembly at the lower end of the generator, but the other parts are the same as those of the second embodiment of the present invention described above, and thus a separate reaction torque transmission mechanism 900 will be described with respect to the present embodiment.

This separate reaction torque transfer mechanism 900 includes a nacelle ring gear 924, a ring gear 964 and a reaction torque transfer shaft 980, the nacelle ring gear 924 being mounted on a flange 922 formed at the lower end of the hollow shaft unit 920, the ring gear 964 being attached to the outer surface of the turret 962 of the rotating base assembly 960, the reaction torque transfer shaft 980 including a nacelle pinion 982 and a reaction torque transfer pinion 984, the nacelle pinion 982 being attached to an end portion of the reaction torque transfer shaft 980 and engaging with the nacelle ring gear 924 of the hollow shaft unit 920, the reaction torque transfer pinion 984 being attached to the other opposite end portion of the reaction torque transfer shaft 980 and engaging with the ring gear 964 of the turret mechanism 900, and reaction torque transfer shaft 980 is rotatably coupled to a plurality of supports 942, the plurality of supports 942 are arranged to be spaced apart at a predetermined interval on the inner wall of the tower body 940.

The coupling of the separate reaction torque transfer mechanism 900 between the hollow shaft unit 920 and the rotating base assembly 960 may be different from the above-described structure as long as it can rotate. Further, the rotating base assembly 960 may also have a structure different from the above-described structure as long as the spindle 722 coaxial with the rotor shaft 610 of the generator 600 is rotatably supported in the support base of the generator 600.

Although the flange 922 has been described as being integrally formed at the lower end of the hollow shaft unit 120, the flange may be separately formed and attached to the lower end of the hollow shaft unit 120.

According to the present embodiment, the reaction torque is balanced by the reaction torque transfer shaft 980 installed within the tower body 940, and thus, the efficiency of installation and management of the wind turbine is conveniently improved.

In general, a wind turbine according to this embodiment of the invention comprises:

a rotating part 300, the rotating part 300 being provided with a main shaft 220 for converting wind power into mechanical rotational kinetic energy, and the rotating part 300 being installed to be horizontal with respect to the ground;

a nacelle assembly 200 in which a main shaft 220 of a rotating part 300 is mounted in the nacelle assembly 200;

a power transmission shaft 140, the power transmission shaft 140 being vertically connected to the main shaft 220 of the nacelle assembly 200 through a gear combination, and the power transmission shaft 140 receiving rotational kinetic energy of the rotating part 300 transmitted to the power transmission shaft 140;

a hollow shaft unit 920, the hollow shaft unit 920 having an upper end coupled to a lower side of the nacelle assembly 200 and a lower end extending downward, and the hollow shaft unit 920 having a nacelle ring gear 924 mounted on a flange 922 formed at the lower end thereof;

a tower 960, the tower 960 including a tower body 940, an upper portion of the tower body 940 being combined with an outer circumferential surface of the hollow shaft unit 920 through upper and lower yaw bearings 162, and a lower end being fixed to a support base, and the power transmission shaft 140 extending within the tower body 940 from the hollow shaft unit 920;

a generator 600 having a housing 640, a rotor shaft 610, a multi-pole rotor 620 coupled to rotor shaft 610, and a multi-pole stator 635 arranged at a distance from rotor 620, wherein housing 640 is arranged to be coupled to power transmission shaft 140 to generate electricity by rotational kinetic energy transmitted by means of power transmission shaft 140;

a rotating base assembly 700, the rotating base assembly 700 being located on a support base of a tower 960, the rotating base assembly 700 rotatably supporting a spindle 722, the spindle 722 being coaxially coupled with the rotor shaft 610 of the generator 600; and

a reaction torque transfer shaft 980, the reaction torque transfer shaft 980 being rotatably coupled between the nacelle ring gear of the hollow shaft unit 920 and the ring gear of the rotating base assembly 960.

Fig. 10a shows a configuration of a wind turbine according to a fifth embodiment of the present invention, and fig. 10b shows a cross-section taken along line h-h' in fig. 10 a.

Referring to fig. 10, a wind turbine according to a fifth embodiment of the present invention adopts a configuration having a parallel drive device for a plurality of small generators vertically arranged according to power generation capacity, and has the same structure as that of the above-described second embodiment, and therefore, the present embodiment will be described below with respect to a parallel drive mechanism 1000.

The parallel drive mechanism 1000 having a plurality of generators includes: a housing including a center bearing housing 922 having a bearing for supporting the power transmission shaft 140, and two bearing housings 925 formed opposite to the lower side of the housing 920 and coupled to the lower end of the hollow shaft unit 120; a main gear 940, the main gear 940 being attached to a lower end of the power transmission shaft 140 held by a bearing housing 922; and two sub-gears 960 engaged with the main gear 940 and axially coupled with bearings in the two bearing housings 925 and coupled to a rotating shaft of the generator 980, respectively.

Although two small generators 980 are shown and described above, there may be three or more bearing blocks 925 and sub-gears 960 arranged parallel to each other to facilitate handling and transporting the same number of generators.

Fig. 11a shows a configuration of a wind turbine according to a sixth embodiment of the present invention, and fig. 11b shows a sectional view taken along line i-i' in fig. 11 a.

Referring to fig. 11, the configuration of a wind turbine according to a sixth embodiment of the present invention is the same as that of the wind turbine of the fifth embodiment except that a horizontal generator driving mechanism 1100 is disposed between a lower portion of a hollow shaft unit 120 and a rotation base assembly 700, and thus the horizontal generator driving mechanism 1100 will be described hereinafter with reference to the present embodiment.

The horizontal generator driving mechanism 1100 includes: a housing 1120, the housing 1120 being formed with a central bearing housing 922, the central bearing housing 922 having a bearing therein, and the housing 1120 being disposed between a lower portion of the hollow shaft unit 120 and the rotating base assembly 700; a first bevel gear 148 attached to a lower end of the power transmission shaft 140 exposed downward through a central bearing housing of the housing 1120; and a second bevel gear 142 coupled to the horizontal rotation shaft of the power transmission unit 600 through the horizontal rotation shaft of the power transmission unit. According to this embodiment, assembly and maintenance of the wind turbine is facilitated because the generator is mounted horizontally, rather than vertically.

Fig. 12 illustrates a pitch control mechanism of a wind turbine according to a seventh embodiment of the invention, wherein fig. 12a is a block diagram of the pitch control mechanism in a free (Stroll) control position and fig. 12b is a partial enlargement of fig. 12 a.

Referring to fig. 12, a wind turbine according to a seventh embodiment of the present invention will be described according to a pitch control mechanism 1200 for adjusting the rotation angle of the blades according to the wind speed and the driving conditions, since any configuration of the aforementioned embodiments may be used for other parts or components of the wind turbine of the present embodiment.

Pitch control mechanism 1200 includes: a push-pull rod 1240, the push-pull rod 1240 being arranged through the hollow of the hollow main shaft 1220 formed by the main shaft 200 of the nacelle assembly 200: a linkage 1260 and an actuator 1280, the linkage 1260 and the actuator 1280 being coupled to either end of two opposite ends of the push-pull rod 1240, respectively; and a pivot joint pin 1300, the pivot joint pin 1300 being eccentrically disposed on each end of the blade 310 provided on the hub 320 so as to change an angle to a controlled position and the pivot joint pin 1300 being connected to the link 1260 such that the blade 310 is at a predetermined angle to the rotational axis of the hub 320 attached to the hollow main shaft 1220. When the blade 310 is rotated by wind causing the hollow main shaft 1220 and the actuator 1280 to rotate, the push-pull rod 1240 having an end attached to the actuator 1280 reacts such that the link 1260, an end of which is rotatably coupled to the other end of the push-pull rod 1240, forces the pivot joint pin 1300 through the other end of the push-pull rod to pivot the blade 310, thereby changing the angle of the blade 310 as desired, wherein the end of the blade is eccentrically arranged from the pivot joint pin 1300.

Thus, known pitch control mechanisms with eccentrically pivotable blades operate through the eccentric pivot joint pin 1300, the linkage 1260 coupled with the eccentric pivot pin 1300, the push-pull rod 1240, the hollow main shaft 1220 and the actuator 1280, eliminating the clearance due to wear of the connecting parts, reducing the weight of the rotating part, and achieving a balance of the weight of the nacelle assembly.

Industrial applicability

As described above, the wind turbine according to the present invention can realize a reaction torque balancing mechanism and a free yaw nacelle assembly with a simplified structure by transmitting rotational kinetic energy of a rotating part to a generator mounted at a lower part of a tower through a power transmission shaft vertically arranged in the tower, wherein reaction torque generated at the nacelle assembly by driving torque generated in the power transmission shaft due to a power generation load is balanced by using electromagnetic force of the generator, and thus construction costs can be reduced by reducing the overall weight of the wind turbine.

Further, the wind turbine according to the present invention can smoothly and pivotally support the heavy generator coupled to the lower portion of the vertical power transmission shaft by turning the base assembly, thereby achieving free yaw of the nacelle assembly in the direction in which the wind blows, and reducing the period in which yaw error may occur because the response speed is faster than active yaw even when the wind direction is frequently changed.

Further, the wind turbine according to the present invention can reduce the height of the power transmission shaft and the tower body in units or segments by dividing the long body of the power transmission shaft into a plurality of power transmission shaft units or sections that can be sequentially connected in a plurality of stages, thereby preventing self-excited vibration when the power transmission shaft rotates, and reducing construction costs and construction period.

Although the present invention has been described in accordance with non-limiting embodiments, it is not intended to limit the scope and spirit of the present invention, but rather, it is intended that various modifications, alterations, and adaptations may be made within the spirit and scope of the present invention. It is not intended to be exhaustive or to limit the invention to the precise form disclosed in the foregoing description or illustrated in the accompanying drawings. It is therefore to be understood that the scope of the present invention is not limited to the foregoing exemplary embodiments, but is defined by the following claims and their equivalents.

Claims

1. A wind turbine, comprising: a rotating part provided with a main shaft for converting wind power into mechanical rotational kinetic energy, and installed horizontally with respect to a ground surface; a nacelle assembly in which the main shaft of the rotating part is mounted; a power transmission shaft vertically coupled to the main shaft of the nacelle assembly through gear engagement, rotational kinetic energy of the rotating portion being transmitted to the power transmission shaft; a hollow shaft unit having an upper end coupled to an underside of the nacelle assembly and a downwardly extending lower end; a tower including a tower body having an upper portion coupled to the hollow shaft unit and a lower end fixed to a mounting point support, wherein the power transmission shaft is disposed in the hollow shaft unit; and a generator, the generator comprising: a housing, a multi-pole rotor having a shaft, and a plurality of stators spaced apart from the rotor, wherein the housing is coupled and fixed to the lower end of the hollow shaft unit and thus suspendedly mounted on the hollow shaft unit, and the shaft of the rotor is coupled to the power transmission shaft via a coupling such that electric energy is generated by the rotational kinetic energy transmitted through the power transmission shaft, wherein a reaction torque of the nacelle assembly transmitted to the stator of the generator is balanced by a driving torque generated by an electromagnetic force caused according to lenz's law by a rotating magnetic field from the rotor.

2. The wind turbine of claim 1, further comprising an adapter unit disposed in the wind turbine and coupled to an outer surface of the hollow shaft unit to allow the hollow shaft unit to rotate for free yaw and to be supported by the tower body, the adapter unit including an inner adapter and an outer adapter attached to the outer surface of the hollow shaft unit by being joined with a pair of yaw bearings disposed between protrusions on an upper portion of the outer surface of the hollow shaft unit.

3. The wind turbine of claim 1 or 2, further comprising a rotating base assembly rotatably supporting a spindle coaxially coupled with a rotor shaft to a support base of the generator.

4. Wind turbine according to claim 1 or 2, wherein the power transmission shaft and the hollow shaft unit comprise a plurality of parts assembled together by connectors.

5. The wind turbine of claim 4, wherein the connector comprises: an inner bearing housing having a central bore for receiving the power transmission shaft in the hollow shaft unit; an outer bearing seat disposed around the inner bearing seat; and a plurality of edge portions formed on an outer surface of the outer bearing housing at regular intervals and attached to an inner wall of the tower body, wherein the inner bearing housing and the outer bearing housing are provided with a pair of upper and lower bearing assemblies, respectively.

6. The wind turbine of claim 1 or 2, further comprising a parallel drive mechanism comprising: a housing having a bearing housing for receiving and holding the power transmission shaft and coupled to a lower portion of the hollow shaft unit; a main gear attached to a lower end of the power transmission shaft held in the bearing housing; a plurality of sub-gears axially coupled to a lower portion of the housing to engage with the main gear at a predetermined angle and axially coupled with and at respective shafts of a plurality of generators.

7. The wind turbine of claim 5, further comprising a horizontal drive mechanism disposed between a lower portion of the hollow shaft unit supporting the nacelle assembly and a rotating base assembly, the horizontal drive mechanism comprising: a housing disposed between a lower portion of the hollow shaft unit and the rotating base assembly; a first bevel gear fixed to a lower portion of the power transmission shaft exposed through the housing; a second bevel gear arranged to engage with the first bevel gear and coupled to a horizontal rotor shaft of the generator.

8. A wind turbine according to claim 1 or 2, further comprising a pitch control mechanism for adjusting the angle of the blades of the rotating part, wherein the pitch control mechanism comprises: a push-pull rod disposed in a longitudinal hollow formed in the main shaft of the nacelle assembly; a connecting rod and a linear actuator respectively coupled to either one of two opposite ends of the push-pull rod; and a pivot joint pin coupled to the link and eccentrically disposed to each end of the blade of the rotating part such that the blade can form a predetermined angle with a rotation axis of the rotating part, which can be changed with a direction of wind.

9. A wind turbine, comprising: a rotating part provided with a main shaft for converting wind power into mechanical rotational kinetic energy, and installed horizontally with respect to a ground surface; a nacelle assembly in which the main shaft of the rotating part is mounted; a power transmission shaft vertically connected to the main shaft of the nacelle assembly through gear engagement, to which rotational kinetic energy of the rotating portion is transmitted; a hollow shaft unit having an upper end coupled to an underside of the nacelle assembly and a downwardly extending lower end; a tower including a tower body having an upper portion coupled to the hollow shaft unit and a lower end fixed to a mounting point support, wherein the power transmission shaft is disposed in the hollow shaft unit; a generator, the generator comprising: a housing, a multi-pole rotor having a shaft, and a plurality of stators spaced apart from the rotor, wherein the housing is coupled and fixed to the lower end of the hollow shaft unit such that electric energy is generated by the rotational kinetic energy transmitted by means of the power transmission shaft; a rotating base assembly for rotatably supporting a spindle on a support base of the generator; and a reaction torque transfer shaft rotatably coupled between the hollow shaft unit and the two ring gears of the rotating base assembly.