Vertical axis wind turbine and method for operating such a turbine
10871143 · 2020-12-22
Assignee
Inventors
Cpc classification
Y02E10/74
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
F05B2260/507
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F05B2260/79
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F05B2260/5032
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F05B2260/76
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F03D3/066
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F03D3/068
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F05B2270/32
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F03D3/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F05B2260/505
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F03D7/06
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F05B2270/326
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F05B2260/71
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F03D3/005
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F03D9/25
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F05B2270/327
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F05B2270/321
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F05B2260/503
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F05B2260/72
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F03D3/06
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F03D3/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F03D7/06
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F03D9/25
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
H02K7/18
ELECTRICITY
Abstract
A vertical axis wind turbine includes two or more cells arranged one above the other along a vertical machine axis, wherein each of the cells includes a plurality of vertical blades which are arranged within the cell distributed on a concentric circle about the machine axis and which are connected so as to be able to move together on this circle and which are rotationally fixed with a main shaft, and wherein the blades in the cell are each individually mounted so as to be able to rotate about a vertical axis of rotation which in particular runs internally through them.
Claims
1. A vertical wind turbine, comprising a plurality of vertical blades and a plurality of radial arms, with each blade of the plurality of blades supported at a distal end of at least one radial arm of the plurality of radial arms, so that the blades are rotationally fixed with a main shaft of the wind turbine, wherein the blades are each individually mounted at said end of the respective at least one radial arm so as to be able to rotate about a vertical axis of rotation running internally through each of the blades, wherein to each of the blades means are associated, so that the blade is made to adopt, during the circulation about the machine axis and independently of the other blades, an angular position about the respective axis of rotation of the blade, wherein on said end of the respective at least one radial arm, a wind measurement device is fixed, and wherein the wind turbine is configured to actively control said angular position according to measured values of a relative wind speed, a relative wind flow direction, a rotational speed of the wind turbine, and a position of the individual blade along the circulation of the individual blade around a machine axis of the wind turbine.
2. The vertical wind turbine according to claim 1, wherein the wind measurement device is positioned at a distance from the end of the arm, the distance from the end of the arm is sufficient to avoid any influence of an air turbulence zone of the arm end on the wind measurement device.
3. The vertical wind turbine according to claim 1, wherein the wind measurement device on each arm allows to individually control the respective blade in an independent manner.
4. The vertical wind turbine according to claim 1, wherein the rotational position is determined depending on at least one of a relative wind flow direction and a relative wind speed with respect to the blade.
5. The vertical wind turbine according to claim 1, wherein the wind measurement device is an ultrasound anemometer.
6. The vertical wind turbine according to claim 1, wherein on each arm, at a blade bearing, a force measurement device for radial and tangential force direction is provided.
7. The vertical wind turbine according to claim 1, wherein at least three arms form a ring.
8. The vertical wind turbine according to claim 7, wherein the blades are positioned on the ring in order to rotate through 360.
9. The vertical wind turbine according to claim 7, wherein the blades are rotatably supported at an end of each blade on the ring.
10. The vertical wind turbine according to claim 7, wherein the means for changing the angular position of the blades are positioned on the ring.
11. The vertical wind turbine according to claim 10, wherein the means for changing the angular position of the blades comprise an electrically driven motor or a hydraulically driven motor.
12. The vertical wind turbine according to claim 11, wherein a rotational movement of the motor is directly transmitted to the corresponding blade.
13. The vertical wind turbine according to claim 11, wherein the hydraulically driven motor is positioned with a motor axis in a plane of the rings.
14. The vertical wind turbine according to claim 11, wherein the hydraulically driven motor has a motor axis extending perpendicularly to a plane of the rings.
15. The vertical wind turbine according to claim 11, wherein the rotational movement of the electrically driven motor is transmitted by gears to the corresponding blade.
16. The vertical wind turbine according to claim 15, wherein the electrically driven motor is positioned with a motor axis in a plane of the rings, and wherein the rotational movement of the electrically driven motor is transmitted between the gears by a toothed belt.
17. The vertical wind turbine according to claim 15, wherein the electrically driven motor has a motor axis extending perpendicular with respect to a plane of the rings, and wherein an angular gear is interposed for transmitting the rotational movement.
18. The vertical wind turbine according to claim 1, wherein the main shaft comprises a plurality of portions, the plurality of portions are serially positioned in the axial direction, and wherein the plurality of portions is connected to each other by flanges.
19. The vertical wind turbine according to claim 18, wherein the main shaft comprises a lower cylindrical portion, a middle portion, and an upper cylindrical portion, wherein the middle portion conically widens in an upward direction, and wherein the upper cylindrical portion has an outer diameter, which outer diameter is greater than an outer diameter of the lower cylindrical portion.
20. The vertical wind turbine according to claim 19, wherein the lower cylindrical portion supports a rotor of an electrical energy generating generator.
21. The vertical wind turbine according to claim 1, wherein, for rotatably supporting the main shaft, a bearing pin is provided at a lower end of the main shaft and a supporting roller track is provided at an upper end of the main shaft.
22. The vertical wind turbine according to claim 1, wherein an upper bearing of the main shaft is a supporting roller bearing, absorbs vertical upper reaction wind forces of the main shaft, and is supported by a supporting frame, the supporting frame obliquely widens up in a downward direction, on foundations positioned outside the machine axis, wherein lower axial and radial bearings of the main shaft are housed inside a generator housing, the generator housing is fixed to upper struts inside the machine house, and wherein the machine house is suspended from the supporting frame.
23. A method for operating a vertical wind turbine, wherein an angular position of an individual blade of a plurality of blades of the wind turbine around a respective axis of rotation of the individual blade is actively controlled, independently from the other blades of the plurality of blades, according to measured values of a relative wind speed, a relative wind flow direction, a rotational speed of the wind turbine, and a position of the individual blade along the circulation of the individual blade around a machine axis of the wind turbine, wherein each blade of the plurality of blades is supported at a distal end of at least one radial arm of a plurality of radial arms, and wherein on said end of the respective at least one radial arm, a respective wind measurement device is fixed for determining the relative wind flow direction and the relative wind speed with respect to the respective blade.
24. The method according to claim 23, wherein the wind measurement device determines in each instant in time during circulation of the respective blade around the machine axis, the relative wind flow direction and speed, with respect to the at least one arm and therefore to the respective blade.
25. The method according to claim 23, wherein for a blade angle describing a deviation of the respective blade from a base position, in a tangential direction with respect to a circulation circle around the machine axis, virtual cam discs are provided, the virtual cam discs define a variation of the blade angle with the position of the respective blade on the circulation circle, and wherein the active control of the respective blade is performed according to the virtual cam discs.
26. The method according to claim 25, wherein for selecting the virtual cam discs used for the active control of the respective blade, a tip-speed ratio of the wind turbine is continually determined, wherein the tip-speed ratio indicates a ratio of a peripheral velocity of the respective blade to wind speed, and wherein according to the determined tip-speed ratio, the virtual cam disc used for active control of the respective blade is selected or different virtual cam discs are exchanged.
27. The method according to claim 25, wherein the virtual cam discs are referenced to a zero position of the wind turbine, and wherein the zero position depends on the relative wind flow direction.
28. The method according to claim 23, wherein the measurement device is adapted to determine brief high local turbulences which may lead to a blade and turbine overload, for performing a relieving blade adjustment or a complete blade disconnection.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The invention is explained in the following by means of exemplary embodiments in connection with the drawing. In particular:
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DESCRIPTION OF THE INVENTION
(18) In
(19) The wind turbine 10 of
(20) The structure of rings 11, 16 and 19 is obtained from
(21) Cells Z1, Z2 are non-rotatably connected with their blades 13 through a central pipe 15 and 18 to a vertical main axis 20, which is rotatably supported underneath cells, so that they may rotate about the machine axis MA together with the main axis 20. The main axis 20 is rotatably supported at the upper end in a bearing support 23 with support rollers, which is supported by a frame of obliquely downwards spread pipes 24 on external foundations 29. In the example of
(22) The main axis 20 is composed, in the example of
(23) As is shown in
(24) In
(25) Energy is supplied to actuators 39 or 39a,b through corresponding lines by a central supply unit and these are controlled by control signals according to the settings of a control unit. If hydraulic actuators (motors) are used instead of electric motors, the energy is provided by a central hydraulic unit through corresponding hydraulic conduits.
(26) An overview of the concept of active blade control is provided in block diagram of
(27) Blades 13 or F1-F6 of cells Z1 and Z2 are actively rotated by actuators 39a (through angular gears 52) or 39b (directly) about their longitudinal axis. Any blade angle (angle between the tangent to the circulation circle of rotor and a cord of blade) may be individually set for each blade in each position on the circulation circle.
(28) The object of the active blade control is to operate with all (example 12) blades 13 or F1-F6 in both cells with a blade angle which varies with the rotor position. Depending on the wind speed and rotational speed of rotor another curve of blade angles with respect to rotor position is operated. To this end, various virtual cam discs are generated, which are stored in a memory. The blade angle then follows the edge curve of the selected virtual cam disc. The zero point of the rotor position is a function of the wind direction. Wind direction and wind speed are measured by an wind speed sensor 67 and a wind direction sensor 68.
(29) The wind measurement is of particular importance in the present turbine of
(30) Because of static and dynamic loads on blades, the rotor is subdivided, along the active height, according to size of wind turbine, into one to four cells (two cells Z1 and Z2 in the example of
(31) Since all rotor cells are fixedly connected to the rotor, they also rotate with the same speed of the rotor. The wind direction and speed may however greatly vary along the active height of rotor, in particular in the case of huge (tall) turbines. In order to ensure an optimal thrust control, at each moment during the rotor rotation, the speed and direction of the relative wind flow of each blade should be exactly known. By a static wind measurement, the wind speed and direction may be measured along the height in a vertical direction and at a distance from the rotor (wind measurement pole). Since the wind measurement pole is at a fixed distance from the turbine, in case of an unfavorable wind direction, it will be in the wind shadow of the turbine, and, also because of the distance, will provide incorrect measurements, which do not correspond to the real conditions on the blades.
(32) It is therefore proposed to fix, for each ring, externally on each ring arm 100, a respective wind measurement device Wl-W3 (
(33) It is known that the wind direction and speed may greatly vary along the active height of rotor (wind shear and turbulences). If such phenomena can not be locally and temporally measured with sufficient precision, in order to optimally control the blade 13, the turbine will have a highly reduced aerodynamic efficiency. If the measurement takes place in each cell Z1, Z2 on the upper and lower side of circumference, in a dynamic and temporally proximate way, each blade may also be always controlled at an optimal relative angle of attack. In order to determine the wind conditions at middle height of blade, the respective wind measurements on the upper and lower side of blade have to be mediated, in order to provide the blade control signal. From the measurement of the relative flow, at each moment of time, through the rotor peripheral speed, the absolute wind speed and direction may also be calculated by trigonometric means. Based on these measurements, the optimal tip-speed ratio of turbine and the optimal corresponding blade angle of attack may be determined in a very short time frame.
(34) The measurement device may also determine brief high local turbulences which may lead to a blade and turbine overload. Consequently, an optional relieving blade adjustment or a complete blade disconnection (release) may be performed. Measurements with wind measurement devices W1-W3 on each arm 100 for each ring allow to individually control each cell with their respective blades in an independent manner.
(35) It is also proposed to install on each cell Z1, Z2 on the lower or upper ring, on each arm 100, at the blade bearing, a force measurement device K1-K3 for radial and tangential force direction. Through the tangential force measurement, together with the wind measurement device W1-W3, the blade propulsion and therefore the turbine efficiency may be optimized. Signals from both these measurement devices W1-W3 and K1-K3 shall adaptively improve the efficiency of the turbine by use of a self-learning control program.
(36) The radial force measurement signal should, together with the tangential force measurement signal, constantly monitor the load profile of blade. Through this measurement the frequency and intensity of blade load and therefore of residual operating life of blade may be determined.
(37) As an alternative or in addition to above said force measurement for determining the blade load, a strain gauge may also be provided at blade central surface (for example for blade 13: DM in
(38) The basic concept of an active blade control is shown in block diagram in
(39) The virtual cam discs (different blade angle curves according to rotor position) are stored on the rotor (motion controller 58). They may also be changed through the Wi-Fi connection. Wind speed, wind direction and rotor speed are processed on the tower (not rotating) through an I/O of a programmable logic controller (PLC) 64, which is operating with a computer 70. The virtual cam disc which has to be taken, is communicated through the Wi-Fi connection to the motion controller 58 on rotor. I/O are available on the rotor as well as on the tower.
(40) The 6 actuators 39a or 39b in the simplest case follow the same cam disc, however with an angular offset of 120 (for example with 3 blades for each cell). The zero value of the rotor position depends on the wind direction. If, in case of higher systems, and/or with more than two cells, the wind speeds for the cells are very different from each other, for each of cells a corresponding virtual cam disc is selected according to the corresponding wind speed. For each cell Z1, Z2 a corresponding wind speed (v.sub.w) is determined, depending on the height above ground, and the angular position of individual blades 13, F1-F6 of cell is actively controlled according to the wind speed (v.sub.w) determined for the cell. Since the dependence of the wind speed from height over ground follows a standard curve, it is sufficient to measure the wind speed at a height, in order to determine on its basis the values for other heights. All cells have the same rotational speed about the machine axis MA, but because of the different heights, they have different wind speeds. Correspondingly different tip-speed ratios are obtained, which then are averaged for the entire system and have to ensure a maximum of energy production.
(41) The electric cabinet with the motion controller 58 is provided on the rotor. The rotor position should also be sensed on the rotor. To this end, a corresponding encoder may be used. In the example of
(42) The active blade control receives a plurality of incoming signals, directly from a measurement system, which includes the wind speed sensor 67, the wind direction sensor 68 and possibly a rotor torque sensor 69. In addition, impulses for the rotational speed are supplied. Based on these input signals, the blade control 64 determines how the individual blades have to be controlled (which cam discs are used, where is the zero point of the rotor position). The control signals from the motion controller 58 flow through a power module 59 to an output module 60 and from here through a distribution box 55 to the individual actuators 39a and 39b.
(43) The profile of blade angle is periodically newly selected (different cam discs). The wind direction defines the zero position of rotor. Based on the input signals required for adjustment, a median over a predetermined time is calculated. Both the refresh time and the time window for the averaging of the adjustment parameters should be freely selectable. A specific control 61 may provide commands for the switching off of turbine or rotational speed reduction.
(44) The maximum number of different blade angle profiles (virtual cam discs), which may be defined, is limited by the motion controller 58 and may for example be equal to 99. The blade angle profile to be used depends on the operating conditions and the tip-speed ratio of the turbine. The tip-speed ratio is calculated in a way known per se, from the wind speed v.sub.w and the rotor speed (or the rotor peripheral velocity).
(45) The theoretical optimal blade angle profile for a blade 13 has been calculated by means of an analytical model for different tip-speed ratios. An example of a tip-speed ratio of 0.4 (a) together with a schematic view of the physical positions of blades each 30 (b) is shown in
(46) It is to be noted that the maximal accelerations in
(47) Blades are positioned according to a virtual lead axis. The lead axis is determined by a NULL-impulse (zero position 54) and the rotational speed. The PLC 64 stores with a predetermined frequency the current wind speed, the rotor speed and the wind direction. The median is periodically calculated based on the wind speed and rotor speed. These provide the averaged tip-speed ratio by calculation through the last time window, and the cam disc is selected. The median of the wind speed is also periodically calculated. It then allows the NULL position of the cam disc to be determined.
(48) If the tip-speed ratio of turbine is <0.4 a constant blade angle profile is used, in order to increase the rotational speed. As soon as the tip-speed ratio is >0.4, the turbine is operative.
(49) When the power is decreased, the wind turbine is decelerated by the generator, in order to set the speed to zero. The blade control receives from control 61 of system a signal that indicates that the operating condition ramp down has been reached and the blade drives 39a and 39b are de-energized or, in case of a hydraulic drive, the hydraulic motors are released.
(50) The rotor speed is 0 and brakes of wind turbine are closed. The blade control is not deactivated, so that it doesn't lose the rotor position. The motors are de-energized or the hydraulic motors have no oil pressure. The blades 13 therefore align with the wind.
(51) The wind turbine is decelerated by the brake 21 as quick as possible. The blades 13 are physically current-free or oil pressure free in case of actuation of the emergency command.
(52) A block diagram which is analogous to
(53) The hydraulic actuators HA11-HA1n and HA21-HA23 may be particularly compact and provide high adjustment forces. By opening the corresponding valves, it is very easily possible to ensure the necessary freewheeling of blades.
(54) While several embodiments of the invention are shown in the accompanying figures and described in detail above, other embodiments will be apparent to, and readily made by, those skilled in the art without departing from the scope and spirit of the invention. Accordingly, the foregoing description is intended to be illustrative rather than restrictive. The invention described above is defined by the appended claims and all changes to the invention that fall within the meaning and range of equivalency of the claims are to be embraced within their scope.
LIST OF REFERENCES
(55) 10 wind turbine (vertical)
(56) 11 upper ring
(57) 12 axis of rotation
(58) 13 blade
(59) 14, 17 rod
(60) 15, 18 pipe
(61) 16 middle ring
(62) 19 lower ring
(63) 20 main shaft
(64) 21 brake
(65) 22 rotor (generator)
(66) 23 bearing mount
(67) 24 pipe
(68) 25 rod
(69) 26 machine house
(70) 29 foundations
(71) 31, 33 rods
(72) 32 pipe
(73) 34 plane
(74) 35 pipe
(75) 36 flange
(76) 37 rib
(77) 38 bearing support
(78) 39 actuator (blade)
(79) 39a, b servomotor
(80) 40 supporting roller track
(81) 41 upper portion (cylindrical)
(82) 42, 44 flange
(83) 43 middle portion (conical)
(84) 45 lower portion (cylindrical)
(85) 46 lower bearing pin
(86) 47, 48 bearing (for example, self-aligning roller or ball bearings)
(87) 49, 50 gear
(88) 51 cover
(89) 52 angular gear
(90) 53 rotor block
(91) 54 zero position
(92) 55 distribution box
(93) 56 24 VDC voltage supply
(94) 57 Wi-Fi transmitter
(95) 58 motion controller
(96) 59 power module
(97) 60 outlet module
(98) 61 control
(99) 62 collector ring
(100) 63 impulse for rotational speed
(101) 64 PLC
(102) 65 24 VDC voltage power supply
(103) 66 Wi-Fi transmitter
(104) 67 wind speed sensor
(105) 68 wind direction sensor
(106) 69 rotor torque sensor
(107) 70 computer
(108) 71, 72 alternate current power supply
(109) 73 hydraulic aggregate
(110) 100 radial arm
(111) dl diameter
(112) DM strain gauge
(113) FP blade profile
(114) F1-F6 blades
(115) HA11-
(116) HA ln hydraulic actuators (integrated with valves and activation)
(117) HA21-
(118) HA23 hydraulic actuators (integrated with valves and activation)
(119) H1 total height
(120) h1-h3 height
(121) K1-K3 force measurement device
(122) MA machine axis
(123) Wl-W3 wind measurement device
(124) Z1, Z2 cell