WO2013005182A2

WO2013005182A2 - Wind power plant

Info

Publication number: WO2013005182A2
Application number: PCT/IB2012/053445
Authority: WO
Inventors: Jan HYSTAD
Original assignee: Hystad Jan
Priority date: 2011-07-07
Filing date: 2012-07-05
Publication date: 2013-01-10
Also published as: WO2013005182A3

Abstract

An aircraft handling device comprises a member (60) which at one end is rotatably connected to a base (61) and at another, free end, comprises a jaw (66a) having a shape which is complementary to at least a portion of a leading edge portion (21) of the aircraft. The gripper member (66) has a guide slot (70) extending to the back of the yaw and having a transversal closure member (71) whereby an inner portion of the guide slot may be isolated, thus forming a guide channel (72) for an aircraft tether line (26, 29). An aircraft control module (30) comprises one or more attachment devices (38) for lines (24a,b, 25a,b, 26) extending between the control module (30) and an aircraft (20). The control module may be suspended by said lines when the aircraft is in operation, and further comprising attachment means (37) for a tether line (29) connected to a ground-based device. Each attachment device (38) is operable for selectively reducing and extending the length of the individual lines (24a,b, 25a,b, 26). A power plant comprises one or more aircraft (20) tethered to a ground-based structure (5) which has a circular rim (16) with a bearing surface (8a) which is rotatably supported by bearing members (1 la,b, 12a,b) connected to a ground foundation (10). One or more power generators (17) are connected to the ground foundation (10) and rotatably connected to the circular rim (16) via driving means (8, 9). Each aircraft handling device comprises a plurality of extendible telescoping members (60a-c), whereby the torque of the power plant may be increased when the plant is in operation, or used for holding the aircraft when it is in an inactive state.

Description

WIND POWER PLANT

Field of the invention

The invention relates to power generation, more specifically to wind-based power plant utilizing one or more aircraft such as kites, and to an associated handling system and an airborne control module, as set out in the preamble of the

independent claims.

Background of the invention

A traditional wind-based power plant typically comprises a wind turbine having a generator which is driven by one or more turbine blades. The wind turbine is mounted on top of a tall tower, where it is allowed to weather-vane. The wind turbine will also in most cases need a gearbox between the turbine axle and the generator, in order to step up the relatively low rotational speed of the turbine blades. This is a normally a preferred arrangement, because a higher input rotational speed allows for a smaller (and hence less costly) generator.

The state of the art also includes airborne power generation systems. One such system is disclosed by WO 2010/148373 Al (Bevirt, et al.), which describes a tethered airborne electrical power generation system which may utilize a strutted frame structure with airfoils built into the frame to keep wind turbine driven generators which are within the structure airborne. The primary rotors utilize the prevailing wind to generate rotational velocity. Electrical power generated is returned to ground using a tether line that is also adapted to fasten the flying system to the ground. The flying system is adapted to be able to use electrical energy to provide power to the primary turbines which are used as motors to raise the system from the ground, or mounting support, into the air.

The state of the art also inc ludes kites and/or airfoils which by virtue of their movement in the atmosphere provide kinetic energy to a power generator on the ground. One such system is described in WO 2009/142762 Al (Griffith, et al.), which describes a power generation system comprising a kite tethered to a ground station having a crank arm and power extractor. The force of wind captured by the kite is transferred through the crank arm to the power extractor, thus generating power as the kite flies in a circular path.

Another example in this category is WO 2009/147692 A2 (Ippolito), describing a system for launching and controlling an airfoil connected to a ground-based power generator. The system described in this publication has five main components: a rotary base, a movable arm, a jet- type ventilation plant, a variable-geometry system for supporting a wing, and a driving system. The cable driving system, composed of a set of pulleys, rollers and fairleads, is placed externally to the arm. The generator comprises sub-systems and plants for e.g. converting mechanical energy into electric energy, which may be housed inside or outside the rotary base. Yet another example is WO 2010/017495 Al (Varrichio, et al.), describing a kite electrical power system consisting of a line that turns a generator. The line is attached to a kite and to a spool on a vertical axle fixed in a concrete ground anchor. The spool allows 360° of operation for the kite. A separate guide rod, which rotates independently around the axle above the spool, keeps the line properly aligned on the spool. A bevelled gearing system connects the spool to a detached generator. The guide rod rotates according the wind direction, and aids in the winding and unwinding of the spool. A clutch coupled to the gearing system is also described.

The present applicant has devised and embodied this invention in order to overcome shortcomings of the prior art and to obtain further advantages.

Summary of the invention

The invention is set forth and characterized in the main claims, while the dependent claims describe other characteristics of the invention.

It is thus provided an aircraft handling device, characterized by a member which at one end is rotatably connected to a base and at another, free end, comprises a gripper member which is rotatably connected to the member and comprises holding means configured for connection to at least a portion of the aircraft.

In one embodiment, the holding means comprises a jaw having a shape which is complementary to at least a portion of a leading edge portion of the aircraft. The jaw preferably comprises teeth for interaction with at least a portion of the aircraft when the leading edge is in the jaw.

Advantageously, the gripper member comprises a guide slot extending to the back of the yaw and having a transversal closure member whereby an inner portion of the guide slot may be isolated, thus forming a guide channel for an aircraft tether line. The gripper member is in one embodiment rotatably connected to said free end of the member via a bolt which is arranged away frorn the gripper member's centre of mass, and that the jaw is arranged and configured such that the jaw, when the gripper member is in its equilibrium state, assumes a substantially horizontal orientation irrespective of the orientation of the member.

In one embodiment, the member comprises a plurality of telescoping members, and the aircraft comprises a kite. The aircraft handling device may be used for launching and retrieving an aircraft, for holding the aircraft when it is in an inactive state, and for providing support for the main tether line when the aircraft is airborne.

It is also provided an aircraft control module, characterized by one or more attachment devices for lines extending between the control module and an aircraft whereby the control module may be suspended by said lines when the aircraft is in operation, and further comprising attachment means for a tether line connected to a ground-based device, and wherein each attachment device is operable for

selectively reducing and extending the length of the individual lines.

The attachment devices comprise servos receiving control input signals from a control unit within the control module. In one embodiment, the aircraft control module comprises a transceiver for communicating information and/or control signals to/from a remote control facility and/or one or more sensors on the aircraft. An on-board power generator provides electrical power to the attachment devices and the control unit, and sensors provides data on ambient atmospheric parameters and/or tension applied to the attachment devices by the lines. The aircraft is advantageously a kite which is steerable by the reduction and extension of said lines.

It is also provided a power plant, characterized by one or more aircraft tethered to a ground-based structure which has a circular rim with a bearing surface which is rotatably supported by bearing members connected to a ground foundation, and one or more power generators are connected to the ground foundation and rotatably connected to the circular rim via driving means.

In one embodiment, the driving means comprise a gear rim connected to the circular rim, and a gear wheel connected to each generator and configured for rotatable interaction with the gear rim. In one embodiment, the bearing members are roller supports and the circular rim is arranged substantially horizontal.

In one embodiment, the structure comprises one or more aircraft handling devices according to the invention. Each aircraft handling device comprises a member having a plurality of extendible telescoping members, whereby the torque of the power plant may be increased when the plant is in operation.

In one embodiment, the power plant comprises one or more aircraft control modules according to the invention.

The structure advantageously comprises a stowage bay for each aircraft, and a handling device is arranged in each bay. Each aircraft is connected to a respective handling device via a plurality of length-adjustable lines which are connected to a respective control module which is connected to a main tether line which is connected to the handling device.

In one embodiment, a central line is connected at one end to a central point on the aircraft leading edge and at the other end to an attachment device on the control module. In a preferred embodiment, the aircraft is a kite having a rigid or semi-rigid lifting surface. Brief description of the drawings

These and other characteristics of the invention will be clear from the following description of a preferential form of embodiment, given as a non-restrictive example, with reference to the attached drawings wherein:

Figure 1 is a perspective view of an embodiment of the invented power plant, in an inactive state;

Figure 2 is a perspective, and partly cut-away, drawing of the power plant illustrated in figure 1 ;

Figure 3 is a perspective view of a portion of the frame, identifying the rotatable support for the power plant, and the interface between the gear rim and the gear wheel of a power generator;

Figure 4 is a perspective view of a kite and a boom in a partly deployed position;

Figure 5 is a side view of a kite and boom in a launch/retrieve position, the kite being held by the gripper;

Figure 6 is a perspective close-up view of the tip of the boom, and the gripper;

Figure 7 is a perspective view of the gripper;

Figure 8 is a perspective close-up view of the bottom part of the boom, and a control module in its receptacle;

Figure 9 is a perspective view of the control module;

Figure 10 is a block diagram identifying main control components in the control module and their interface with remote sensors and control means, and with the ground-based plant;

Figure 11 is a perspective view of a kite and boom, illustrating the kite flying near the gripper;

Figure 12 is a perspective view similar to that of figure 1 1, but shows the kite hi a state where it is not held by the gripper;

Figure 13 is a perspective view of the power plant in an active state, with three kites deployed; and

Figure 14 is a perspective close-up view of the tip of the boom, and the gripper, in a state when the power plant is in operation. Detailed description of a preferential embodiment

Referring initially to figures 1 , 2 and 3, the power plant 1 comprises a framing 5 with external cladding panels 4. A number (here: three) of kites 20 are arranged in respective bays 14. The framing comprises a truss structure which provides the required stiffness for operation of the plant, and is constructed in a known manner and using commonly available materials. The framing 5 has in the illustrated embodiment a circular, disk-like shape, with a central hub 7 connected via three "spokes" 15 to a circumferential rim 16. Along the rim 16 is attached a gear rim 8, which in addition to the toothed rack also comprises a support portion 8a.

The support portion 8a is rotatably supported by rollers 1 la,b, 12a.b which in the embodiments shown in figure 3 are arranged in pans so as to firmly support and secure the power plant, while allowing rotation in the horizontal plane. The rollers are in turn supported to a foundation 10. which is firmly secured to the ground (not shown) or other firm supporting structure. Although not illustrated, the skilled person will understand that a number of support rollers, arranged aroimd the rim 16, are required in order to provide rotatable support for the power plant.

A gear wheel 9 is arranged for rotatable interaction with the gear rim 8, such that rotation of the framing 5 will rotate the gear wheel 9. The gear wheel 9 is connected to a generator 17 for producing electricity, e.g. incorporated in a suitable

compartment in the foundation. A rotation of the framing 5 will hence produce electric power. Electric cables, etc. are not shown, as these components are known in the art. A number of such gear wheels 9 and associated generators 17 may be arranged along the gear rim 8 (although only one is illustrated). Arranging the generators in this manner provides an inherent gearing and remove the need for gear boxes which are common in the prior art power plants.

Each kite 20 comprises a rigid or semi-rigid lifting surface, having a leading edge 21, a trailing edge 22 and downwardly extending tips 23.

Referring now also to figure 4, the framing comprises base structures 61 and equipment for supporting and handling each respective kite. Each base structure 61 is securely attached to the framing, near the circumferential rim 8 and halfway between two spokes 15. A boom 60 is connected to the base structure 61 via a bolt 62, and is hence rotatable between a stowed position (e.g. as shown in figure 2) and a deployed position (e.g. as shown in figure 13). The boom comprises a support guide tab 64 which enters a corresponding arm guide support 63 when the boom is in the deployed position. The boom also comprises telescoping elements 60a, b,c, such that the boom is axially movable between a retracted position (e.g. as shown in figure 4 and a fully extended position (e.g. as shown in figure 5). Necessary actuators (e.g. mechanical, hydraulic) and power sources for rotating, extending and retracting the boom are not shown, as this equipment is well known in the art. Referring additionally to figure 6 and figure 7, a gripper 66 is rotatably connected to the free end of the boom 60 via bolt 67 and fixtures 68. The gripper 66 comprises a jaw 66a and a guide slot 70 in the lower jaw element and extending to the back of the jaw. A guide pin 71 is arranged across the guide slot at a distance from the back of the jaw, thus defining a guide channel 72. The guide pin 71 may be retracted through the opening 71a, thereby allowing passage in the guide slot 70 and all the way to the back of the jaw. In the illustrated embodiment, the bolt 67 is arranged a distance above the gripper' s centre of mass, such that the jaw is oriented more or less horizontally when allowed to swing freely. The jaw has a shape which matches that of the leading edge 21 , and is dimensioned such that he kite is held by the jaw (see figure 4), preferably with the added friction provided by gripper teeth 69.

Each kite 20 is tethered to the framing via lines running into each respective boom, via a control module and a main tether line, as described in the following. Figure 5 shows a first sets of lines 24a,b connected to one tip of the kite, and a second set of lines 25a,b connected to the opposite tip of the kite. A so-called "mid-line" 26 is connected to the leading edge 21 , at a halfway location 28 between the tips 23 (see figure 11). These lines are all connected to a control module 30, for which a receptacle 65 is provided on the lower portion of the boom 60.

Referring to figure 8 and figure 9, the control module 30, which is air -borne when the plant is in operation, comprises individual line adjusters 38, one for each of the aforementioned lines 24a,b, 25a,b. 26. The line adjusters 38, which each comprise servos and associated drums and pulleys for pulling or releasing on the lines, are only illustrated schematically, as these items are well known in the art. Each line 24a,b, 25a,b, 26 runs through respective openings 34a,b_: 35a.b, 36 in the control module housing and is connected to its respective line adjuster in a known fashion. The lines are not illustrated in figures 8 and 9. Referring additionally to figure 10, the line adjusters 38 are controlled and powered by a power pack 33b, a transceiver 33c and one or more control units 33a (all schematically illustrated at 33 in figure 9), embedded in the control module body. A wind-powered fan generator 32 provides charging power for the power pack. The control module is also furnished with a fin 31 , the main purpose of which is to ensure that the fan driving the generator 32 is facing the prevailing wind direction. A solar cell panel (not shown) may be included in the control module to provide electric power to the power pack.

In figure 10, solid lines indicate power cables, while dotted lines indicate signal transmittal. The transceiver 33c is configured for communicating with one or more sensors 40 on the kite. These sensors 40 sense such parameters as kite position and attitude, and may employ GPS receivers and/or inertial gyros, etc. The kite sensors 40 comprise rechargeable battery packs, which are charged (e.g. via suitable docking stations in the gripper jaw) when the kite is stowed in the stowage bay. The transceiver 33c is also configured for communicating with a control facility 52, remote from the control module 30, via wireless means or a signal cable embedded in or attached to the main tether line. The remote control facility 52 is conveniently located on or near the ground-based structure 1 , and receives signal inputs from sensors 54 (e.g. plant rotational speed, generator power output, ambient

meteorological conditions) and/or a human operator. The control facility 54 thus sends control signals to the control module 30 and also controls the operation of the boom(s) 60 and the associated winches (not shown) for operating the main tether line.

In the control module 30, the control unit 33a is powered by the power pack 33b and/or on-board turbine 32, and communicates with the transceiver 33c, on-board sensors 39 and the line adjusters 38. The sensors are configured for sensing ambient meteorological conditions and kite line tension. Each kite may thus be remotely controlled (e.g. from the ground), either manually of automatically via the airborne, tethered control module 30.

In the lower part of the control module 30 is a hole 37, to which a main tether line (not shown in figures 8 and 9) may be attached. In figure 13, which shows the power plant in operation, it is seen how the kite is connected via lines 24a,b, 25a,b and midline 26 to the control module 30, and how the main tether line 29 connects the control module to the boom 60. The control module is made of a light-weight material having the structural integrity necessary for accommodating the loads generated by the kite.

The main tether line 29 is connected to a winch and drum (not shown) within the base 61. The control module receptacle 65 comprises a central slit 73 (see figure 8), which in addition to providing an alignment device for the control module (by guiding the fin 31), also permits the main tether line to run through the receptacle and into the aforementioned winch drum below. Suitable power systems, control systems, sheaves, etc., for paying out and reeling in the main tether line are well known and need therefore not be illustrated.

The power plant is shown in an inactive state in figure 1; the kites 20 are stowed in their respective bays 14 and the plant is at rest. Activation, or start-up, of the plant is achieved by rotating the booms 60 such that the kites, which are held by their respective grippers 66, are elevated up from their respective bays and thus exposed to the wind. The kites are held in an approximate horizontal orientation, by virtue of the above mentioned off-centre location of the gripper bolt 67 (see e.g. figure 4). When operating the power plant, it is convenient to raise the boom to an upright position and extend the telescopic sections 60a,b,c (see figure 5), before releasing the kite. The kite lines 24a,b, 25a,b and midline 26 are paid out from their respective line adjusters 38 in the control module 30, and the control module 30 is subsequently lifted from its receptacle 65 while the main tether line 29 is paid out. The midline 26 runs through the guide channel 72 in the gripper jaw (described above with reference to figure 7). The length of the kite lines and midline may thus conveniently correspond to the height of the extended telescopic boom 60. The kite is in this state held by the gripper, but the holding power may be supplemented by the tension in the midline, which runs through the gripper guide channel and is connected to the control module, which is connected to the main tether line.

Figure 11 shows the flying kite having been released from the gripper, but still being controlled by the gripper by virtue of the midline 26 running through the guide channel 72 (not shown in figure 1 1). In figure 12, the main tether line 29 has been paid out somewhat and the midline 26 has been released from the gripper

(guide pin 71 has been retracted; see description above with reference to figure 7). In this transitory state, the kite is tethered directly to the sheave and winch (not shown) in the base 61. The next steps in the launching sequence are to retract the elements 60a-c in the telescopic boom, manoeuvre the main tether line 29 into the gripper' s guide slot 70 and insert the guide pin 71 so as to capture the main tether Hue in the guide channel 72, and complete the rotation of the boom to the fully deployed position, as shown in figure 13. When fully deployed, the telescopic boom may be extended to provide a longer arm and thus increasing the torque of the power plant.

Figure 14 illustrates how the main tether line is guided by the guide channel 72 on the gripper 66, and also how the giipper is rotated about its bolt 67 such that the main tether line bears against the back of the guide slot. When the kites have been deployed in this fashion, they will generate pulling forces in the main tether line and thus rotate the plant so as to generate electricity via the gear rim 8 and the gear wheels 9, in a manner which is known in the art. For example, it is customary to control the kites such that they follow a figure-eight pattern. The individual kites are controllable by the line adjusters 38, operated by the control unit 33, which in turn may be operated by a ground-based unit (not shown). Communication between the air-borne control unit 33 (in the control module 30) and the ground-based unit may be via wireless means or via a cable in the main tether line. The control of the kites may be manual, automatic, or a combination of both. The plant may also comprise sensors for measuring the wind speed, for example via a wind speed meter on the control module or via strain gauges associated with the main tether line, and position sensors and attitude sensors. The launching, in-flight control and retrieval of the kites may be performed automatically, based on atmospheric parameters such as wind speed and direction.

Retrieval of the kites and stowage in their respective bays is performed in an essentially reverse process of the launching operations described above. Although the invention has been described with reference to a disk-shaped plant, the invention shall not be limited to such shape, but also encompass other shapes. Also, the invented power plant may comprise fewer or more kites than the three kites described above.

Claims

1. An aircraft handling device, characterized by a member (60) which at one end is rotatably connected to a base (61) and at another, free end, comprises a gripper member (66) which is rotatably connected to the member and comprises holding means (66a, 69) configured for connection to at least a portion of the aircraft.

2. The aircraft handling device of claim 1 , wherein the holding means comprises a jaw (66a) having a shape which is complementary to at least a portion of a leading edge portion (21) of the aircraft.

3. The aircraft handling device of claim 2, wherein the jaw further comprises teeth (69) for interac tion with at least a portion of the aircraft when the leading edge is in the jaw.

4. The aircraft handling device of any one of claim 1 - 3, wherein the gripper member (66) further comprises a guide slot (70) extending to the back of the yaw and having a transversal closure member (71) whereby an inner portion of the guide slot may be isolated, thus forming a guide channel (72) for an aircraft tether line (26, 29).

5. The aircraft handling device of any one of claims 1 - 4, wherein the gripper member (66) is rotatably connected to said free end of the member (60) via a bolt (67) which is arranged away from the gripper member's centre of mass, and that the jaw is arranged and configured such that the jaw, when the gripper member is in its equilibrium state, assumes a substantially horizontal orientation irrespective of the orientation of the member (60).

6. The aircraft handling device of any one of claims 1 - 5, wherein the member (60) comprises a plurality of telescoping members (60a-c).

7. Use of the aircraft handling device of any one of claims 1 - 6, for launching and retrieving an aircraft, for holding the aircraft when it is in an inactive state, and for providing support for the main tether line when the aircraft is airborne.

8. The aircraft handling device of any one of claims 1 - 7, wherein the aircraft comprises a kite.

9. An aircraft control module (30), characterized by one or more attachment devices (38) for lines (24a,b, 25a,b₅ 26) extending between the control module (30) and an aircraft (20) whereby the control module may be suspended by said lines when the aircraft is hi operation, and further comprising attachment means (37) for a tether line (29) connected to a ground-based device, and wherein each attachment device (38) is operable for selectively reducing and extending the length of the individual lines (24a,b, 25a,b, 26).

10. The aircraft control module of claim 9, wherein the attachment devices (38) comprise servos receiving control input signals from a control unit (33a) within the control module.

11. The aircraft control module of claim 9 or claim 10, further comprising a transceiver (33c) for communicating information and/or control signals to/from a remote control facility (52) and/or one or more sensors (40) on the aircraft.

12. The aircraft control module of any one of claims 9 - 11, further comprising a power generator (32) for providing electrical power to the attachment devices and the control unit (33a).

13. The aircraft control module of any one of claims 9 - 12, further comprising sensors (39) for sensing ambient atmospheric data and/or tension applied to the attachment devices by the lines.

14. The aircraft control module of any one of claims 9 - 13, wherein the aircraft is a kite which is steerable by the reduction and extension of said lines.

15. A power plant (1), characterized by one or more aircraft (20) tethered to a ground -based structure (5) which has a circular rim (16) with a bearing surface (8a) which is rotatably supported by bearing members (l la,b, 12a,b) connected to a ground foundation (10), and one or more power generators (17) are connected to the ground foundation (10) and rotatably comiected to the circular rim (16) via driving means (8, 9).

16. The power plant of claim 15, wherein the driving means comprise a gear rim (8) connected to the circular rim (16), and a gear wheel (9) connected to each generator and configured for rotatahle interaction with the gear rim.

17. The power plant of any one of claim 15 or claim 16, wherein the bearing members are roller supports and the circular rim is arranged substantially horizontal.

18. The power plant of any one of claims 15— 17, wherein the structure (5) comprises one or more aircraft handling devices according any one of claims 1 - 8.

19. The power plant of claim 18, wherein each aircraft handling device comprises a member (60) having a plurality of extendible telescoping members (60a-c), whereby the torque of the power plant may be increased when the plant is in operation.

20. The power plant of any one of claims 15 - 19, further comprising one or more aircraft control modules according any one of claims 9 - 14.

21. The power plant of claim 18, 19 or claim 20, wherein the structure further comprises a stowage bay (14) for each aircraft (20), and wherein a handling device is arranged in each bay.

22. The power plant of claim 18, 19 or claim 20, wherein each aircraft (20) is connected to a respective handling device via a plurality of length-adjustable lines (24a,b, 25a,b, 26) which are connected to a respective control module (30) which is connected to a main tether line (29) which is connected to the handling device.

23. The power plant of any one of claims 20 - 22, further comprising a central line (26) connected at one end to a central point (28) on the aircraft leading edge (21) and at the other end to an attachment device (38) on the control module (30).

24. The power plant of any one of claims 15 - 23, wherein the aircraft is a kite.

25. The power plant of claim 24, wherein the kite has a rigid or semi-rigid lifting surface.