EP2852759A1

EP2852759A1 - Floating wind turbine having a vertical axle, with improved flotation stability

Info

Publication number: EP2852759A1
Application number: EP13728460.0A
Authority: EP
Inventors: Jean-Luc Achard
Original assignee: Centre National de la Recherche Scientifique CNRS
Current assignee: Centre National de la Recherche Scientifique CNRS
Priority date: 2012-05-22
Filing date: 2013-05-22
Publication date: 2015-04-01
Also published as: FR2991006B1; WO2013175124A1; FR2991006A1

Abstract

The invention relates to a floating wind turbine (10) comprising a float(14) and a turbine engine resting on the float, said float comprising a floating casing (49), said turbine engine comprising at least one transverse-flow turbine column and a structure for holding the turbines, the holding structure extending by means of a connecting body (70) arranged in the floating casing and pivotably connected to the floating casing by means of at least first and second bearings (84, 82) arranged in the floating casing, the first bearing (84) being arranged above the centre of buoyancy of the floating casing. The wind turbine comprises a generator (65) driven by the turbines and arranged in the floating casing beneath the centre of buoyancy.

Description

FLOATING WIND TURBINE WITH VERTICAL AXIS

WITH IMPROVED FLOTATION STABILITY

Field of the invention

The present invention relates to a floating wind turbine, particularly for use offshore.

Presentation of the prior art

Most wind turbines installed on land include axial flow turbines typically having three blades and whose axis of rotation is parallel to the wind direction. The blades are held by a nacelle at the upper end of a mast. Other onshore wind turbines include transverse flow turbines whose axis of rotation is perpendicular to the wind direction, and arranged horizontally or usually vertically. The blades of a wind turbine rotate a shaft which in turn drives an electric generator.

A current trend is to install offshore wind turbines because the wind is more intense and more constant. Such turbines are called offshore wind turbines. Offshore wind turbines currently in operation also include axial flow turbines. The lower end of the mast holding the axial flow turbine is fixed to the seabed. In soft soil, the lower end of the mast can be while in hard ground, the lower end of the mast can be provided with a concrete base, placed on the seabed. Structures consisting of a mesh of welded tubes (called "jacket") can also be used to attach the axial turbine to the seabed. Such offshore wind turbines can therefore be installed only in shallow water depths, of the order of a few tens of meters. However, shallow sites are limited in number and are not always usable for the installation of wind turbines. It is therefore desirable to design wind turbines at sea whose installation can be carried out further away from the shore. The wind turbine then comprises a partially immersed support structure which comprises at least one float which is, for example, connected to the seabed by anchoring lines. Such wind turbines are called floating wind turbines.

The realization of a floating wind turbine axial flow has drawbacks. Indeed, access to the platform that usually contains the electric generator is difficult.

A first disadvantage of the use of an axial flow turbine is that the mass of the nacelle and the blades can cause the appearance of a significant moment of tilting of the wind turbine which must be compensated.

A second disadvantage of using an axial flow turbine is the nacelle orientation system which incorporates auxiliary rotor yaw correction equipment to position the rotor in the wind. This equipment is essential on large wind turbines, the nacelle being too heavy to be oriented in the wind by a drift. This equipment requires extra maintenance.

A third disadvantage of the use of an axial flow turbine is the drop in reliability with the necessary rise in power of floating wind turbines. At sea, wind turbines suffer from a cost of installation and higher than on land. To monetize instal ^¬ tion of a wind turbine, the trend is to increase the power of the turbines (5-6 MW) and elongation of the blades. However, at sea, wind turbines need to increase reliability, maximize availability and reduce maintenance costs. Some organs poorly follow these antagonistic constraints. Indeed, the hubs wear out quickly under increasing loads induced by the blades. In addition, the gigantism of the blades requires the implementation of specialized equipment and exceptional procedures for their transport to the site, their attachment to the mat, their repair, fixing the turbine on the holding structure, etc. In addition, a speed multiplier must generally be provided between the turbine and the generator. This speed multiplier is one of the main sources of damage encountered in recent years for floating turbines with axial flow turbines in operation. The use of a permanent magnet generator makes it possible, in principle, to suppress the speed multiplier at the cost of a body of imposing size which accentuates the instability of the nacelle mentioned above.

A fourth disadvantage of the use of an axial flow turbine is that it is necessary to introduce thermal regulations for the bearings of the turbine and their lubrication, due to the climatic constraints of the areas where the best cooling regimes meet. winds. At the top of the nacelles, ambient temperature ranges can range from -10 to + 40 ° C.

Examples of floating turbines with transverse flow turbines have been described. The first disadvantage described above is reduced since such floating wind turbines allow in particular to house the electric generator in the float or on the float, which facilitates the stabilization of the wind turbine. By way of example, the document WO03089787 describes a floating wind turbine composed of two transverse flow turbines superimposed on vertical axis and counter-rotating. The request for WO2011056425 discloses a floating wind turbine in which the float comprises a movable portion driven in rotation by a transverse flow turbine and rotating around a central floating portion connected to the seabed by anchoring lines.

The second disadvantage mentioned above is also removed. Indeed, a transverse flow turbine is insensitive to the direction of the wind and does not require an auxiliary lace correction mechanism.

The third disadvantage is in principle greatly reduced. Transverse flow turbines lend themselves easily to the integration of several turbines into the same wind turbine, reducing the size of turbines for a final master torque of the equivalent wind turbine. The transverse flow turbines can thus be stacked in one or two columns, each column rotating one or more vertical coaxial shafts which transfer their power to a single shared generator. The verticality of the axis induced elsewhere on the drive shafts of less bending moments.

The fourth disadvantage disappears, the various machines of the electromechanical conversion being housed in the float.

One of the drawbacks of the use of transverse flow turbines is the lower efficiency obtained with respect to axial flow turbines. To remedy this, it is possible to introduce on both sides of the turbines diffuser type fairings which accelerate the wind seen by the turbines, thus increasing their efficiency and also participating in the turbine holding structure. For such turbomachines consisting of keeled but also stacked transverse flow turbines as previously proposed, the Applicant filed a set of patent applications. Among these, mention may be made of patent applications PCT / FR2006 / 050135 (B6869) and PCT / FR2008 / 051917 (B8450) and French patent applications No. 10/59154 (B10563), PCT / FR2011 / 052781 (B10341) and No. 11/56768 (B11141).

However, it is then necessary to provide a system for orienting these turbomachines suitably with respect to the direction of the wind, because of the presence of the fairings but which nevertheless kept, under certain conditions, a self-orienting character in the wind as described in Application No. 10/59154 (B10563).

However, the weight of the column of turbines and the associated holding structure and the forces exerted by the wind on the column of turbines and on the associated holding structure may cause a moment that may favor the tilting of the floating wind turbine and which can be difficult to compensate.

It would therefore be desirable to propose a floating wind turbine comprising an emergent turbomachine constituted by one or two columns of streamlined transverse flow turbines, each column of turbines being able to orient properly with respect to the direction of the wind and maintaining its verticality in the normal operating conditions of the wind turbine.

summary

An object of an exemplary embodiment of the present invention is to overcome all or part of the disadvantages of floating turbines with transverse flow turbines mentioned above.

An object of an exemplary embodiment of the present invention is to increase the energy efficiency of the turbomachine emerged from a floating wind turbine, consisting of one or two columns of transverse flow turbines.

Another object of an exemplary embodiment of the present invention is to ensure the buoyancy of the turbomachine using a submerged support structure or float, the float leaving the turbomachine free to rotate in the wind along an axis vertical rotation. Another object of an exemplary embodiment of the present invention is to compensate, by the float, the roll and pitch moments that the turbomachine exerts on the float.

Another object of an exemplary embodiment of the present invention is to limit the horizontal displacements of the wind turbine with the aid of the anchoring system.

Another object of an exemplary embodiment of the present invention is to limit the drag that waves exert on the float.

Another object of an exemplary embodiment of the present invention is to limit with the aid of the anchoring system the heave movement of the wind turbine.

One aspect of an exemplary embodiment of the invention provides a floating wind turbine comprising a float and a turbomachine resting on the float, the float comprising a floating hull, the turbomachine comprising at least one column of transverse flow turbines and a structure of maintaining the turbines, the holding structure being extended by a connecting member, located in the floating hull and connected to the floating hull in a pivot connection by at least first and second bearings located in the floating hull, the first bearing being located below the hull center of the floating hull, the wind turbine comprising a generator driven by the turbines and located in the hull floating under said hull center.

According to one embodiment of the present invention, the connecting member extends over more than half the height of the floating hull, the second bearing being located above said hull center, the second bearing being a bearing radial and not being an axial bearing and the first bearing being a radial and axial bearing.

According to one embodiment of the present invention, each turbine comprises a drive shaft, the drive shafts of the column turbines being connected to each other. the others, the connecting member comprising a transmission system connecting, to the generator, the drive shaft of the turbine at the base of the column.

According to one embodiment of the present invention, the transmission system comprises a link drive shaft connecting, to the generator, the drive shaft of the turbine at the base of the column.

According to one embodiment of the present invention, the transmission system comprises a hydraulic pump driven by the drive shaft of the turbine at the base of the column, the hydraulic pump being connected to a hydraulic motor driving the generator.

According to one embodiment of the present invention, the turbomachine comprises an additional column of transverse flow turbines, the drive shafts of the turbines of the additional column being connected to each other, the transmission system further connecting to the generator, the drive shaft of the turbine at the base of the additional column.

According to one embodiment of the present invention, the floating hull is rotational symmetrical and has, in a meridian plane, the transverse profile of the hull of a ship, the ratio between the height of the floating hull and the maximum diameter. floating hull varying from 1.5 to 5.

According to one embodiment of the present invention, the float compartments and comprises a device for filling and emptying water each compartment inde ^¬ pendently of each other.

According to one embodiment of the present invention, the float comprises at least a first steer, a second steer under the first steer, a third steer under the second steer, and a conduit through the second steerage and connecting the first steer to the third steerage , the generator being located in the third steerage, the holding structure being connected to the float by the first and second landing, the second landing being in the first steerage, the first landing being in the third steer or being in the conduit, closer to the third steer than the first steer.

According to one embodiment of the present invention, the floating hull has a reduced section at the level of the waterline.

According to one embodiment of the present invention, the wind turbine comprises unsupported anchor lines, radiating from the floating hull and intended to connect the float to the seabed.

According to an embodiment of the present invention, the wind turbine further comprises a tension line connected to the lowest point of the float and intended to be connected to the seabed.

According to one embodiment of the present invention, the holding structure comprises, for each turbine, vertical uprights on either side of the turbine and at least one horizontal plate attached to the vertical uprights, the turbine being connected to the horizontal plate by a pivoting connection.

According to an embodiment of the present invention, each turbine comprises a drive shaft, the drive shafts of the turbines not being connected to each other, each drive shaft being connected to the generator by a control system. hydraulic transmission comprising a hydraulic pump located in the tray.

Brief description of the drawings

These and other objects, features, and advantages will be set forth in detail in the following description of particular embodiments in a non-limitative manner with reference to the accompanying figures in which:

Figures 1 and 2 show, schematically, two embodiments of a floating turbine turbines transverse flow 1 according to the invention; Figures 3 to 6 are perspective views in section of embodiments of a float of the floating wind turbine according to the invention;

Figure 7 shows, schematically, another embodiment of the float according to the invention; and

Figure 8 is a schematic section of the float of the floating wind turbine of FIG 1 according to a perpendicular plane ^¬ dicular to the axis of rotation of the wind turbines.

For the sake of clarity, the same elements have been designated by the same references in the various figures and, in addition, the various figures are not drawn to scale.

detailed description

Only the elements useful for understanding the invention are described and shown in the figures. In the rest of the description, unless otherwise indicated, the terms "substantially", "about" and "of the order of" mean "to within 10%". In addition, the terms "upper", "lower", "above", "below", "top" and "base" are defined with respect to the axis of rotation of the turbines of the corresponding wind turbine. for example, substantially in the vertical direction.

Figure 1 is a schematic perspective view of an embodiment of a floating wind turbine 10 according to the invention. The floating wind turbine 10 comprises a turbomachine 12 resting on a float 14. The float 14 is connected to the seabed, not shown, by anchoring lines 16. The water level is represented diagrammatically by the line 18. float center 14 corresponds to the geometric center of the immersed volume of the float 14, that is to say the center of gravity of the volume of water displaced by the float 14.

The turbomachine 12 comprises a stack of several stages 20. By way of example, four stages 20 are shown in FIG. 1. The number of stages varies, for example, from 2 to 10.

Each stage 20 comprises:

a frame 21 ensuring the rigidity of the assembly and comprising lateral uprights 22, a horizontal panel upper 26 and a lower horizontal panel 28 connected to the lateral uprights 22; and

a transverse flow turbine 30 disposed between the lateral uprights 22 and the plates 26, 28 capable of rotating about an axis D, for example substantially vertical.

The lateral uprights 22 of a stage 20 are in the extension of the lateral uprights 22 of the adjacent stage above and / or of the adjacent floor below in the stack of stages. The amounts 22 of the stages 20 may correspond to a monobloc element or to distinct elements. The turbines 30 of two successive stages 20 are separated by a horizontal plate 31 formed by the upper panel 26 of the lower stage 20 and the lower panel 28 of the upper stage 20. Each lateral upright 22 has a profiled shape to play, in addition, the role of a fairing.

The transverse flow turbine 30 comprises a drive shaft 32 of axis D and means adapted to drive the shaft 32 in rotation about the axis D under the action of the wind, especially when the wind has an approximately perpendicular direction to the axis D. The drive shaft 32 is maintained at the panels 26, 28 by bearings 34. The stacked turbines 30 form a column 35 of turbines 30 or stack of turbines. The uprights 22 and the plates 31 of the entire turbine engine 12 are integral with each other to form the holding structure 36 of the column 35 of turbines 30.

The drive shafts 32 of the turbines 30 may be connected to each other to form the D-axis drive shaft of the turbine column. The column 35 of turbines 30 drives an electric generator (not visible in FIG. 1) contained in the float 14.

According to an exemplary embodiment, the shafts 32 of the turbines 30 are independent of one another. In this case, each shaft 32 can drive a hydraulic pump, arranged for example at the uprights 22. The hydraulic pump drives a hydraulic motor connected to the electric generator which is housed in the float 14. The axes of rotation of the turbines 30 can then not be confused. Such an example allows autonomous operation of each turbine 30 of the turbomachine 12. In particular, if a turbine, damaged, is blocked, the other turbines can continue to operate.

According to an exemplary embodiment, the shafts 32 are connected to each other and the rotation shaft of the stage 20 at the base of the turbomachine 12 drives the electric generator housed in the float 14, as will be described in more detail thereafter. The shafts 32 of the turbines 30 may form a one-axis shaft D maintained by the trays 31. Alternatively, the shafts 32 of the turbines 30 may be separate elements. Couplings, not visible, between the shafts 32 associated with two adjacent turbines may be provided in the trays 31. These may be flexible couplings or elastic.

Each lateral upright 22 has a profiled shape to play, in addition, the role of a fairing. For each stage, the shrouds 22 favor the suction of the air flow towards the turbine 30. Beyond each turbine 30, the flow engages in a divergent part obtained thanks to the gradual removal of the shrouds 22 one of the other.

The turbine 30 may be any type of transverse flow turbine. More particularly, it may be a transverse flow turbine comprising blades 38 rotating the shaft 32 under the action of lift forces.

The span of each blade 38, measured along the axis D, can vary from 1 to 20 meters. In a plane perpendicular to the axis D, the blades 38 follow in operation a circle centered on the axis D whose diameter may vary from 1 to 15 meters. The height of the blade 38 relative to the diameter (relative height) can vary from 0.5 to 3.

By way of example, the transverse flow turbine is a Darrieus or Gorlov-type turbine, for example Turbines described in Gorlov's publication "Helical Turbines for the Gulf Stream: Conceptual Approach to Design of a Large-Scale Floating Power Farm" (Marine Technology, Vol 35, No. 3, July 1998, pages 175-182, etc.). ).

In addition, the applicant has filed a set of patent applications on transverse flow turbines driven by lift forces in patent applications described above. The turbines 30 may correspond to the turbines described in these patent applications.

FIG. 2 is a schematic perspective view of another embodiment of a floating wind turbine 40 which, with respect to the floating wind turbine 10 represented in FIG. 1, comprises first and second columns of juxtaposed turbines 30 whose axes of rotation D and D 'are parallel. The turbine columns 35 and the holding structure 36 of the turbine columns 35 rest on the float 14.

Each stage 20 of a wind turbine 40 comprises two turbines 30, one belonging to the first column of turbines and the other belonging to the second column of turbines. The rotation shaft 32 of each turbine 30 is held by the upper panel 26 and the lower panel 28 associated. The frame 21 of each floor 20 comprises, in addition to the fairings 22 and panels 26, 28, a central upright 42 interposed between the two turbines 30 of the floor 20. Each upper panel 26 extends between one of the fairings 22 and the central upright 42. The central uprights 42 of the stages 20 may correspond to a monobloc element or to distinct elements per stage.

By way of example, for the wind turbine 10 comprising a single column of turbines, the distance between the leading edges of the shrouds 22 can vary from 1.5 to 20 meters. For the turbine 40 comprising two turbine columns, the distance between the leading edges of the shrouds 22 may vary from 3.5 to 40 meters.

FIG. 3 is a cutaway perspective view of an exemplary embodiment of the float 14 of the wind turbine 10, only the plate 31 at the base of the turbomachine 12 being shown. The float 14 comprises a floating hull 49 containing all of the other elements forming the float 14. The floating hull 49 may have a symmetry of rotation with respect to a vertical axis A. Preferably, for the wind turbine 10, the axis A corresponds to the axis D. By way of example, the section of the floating hull 49 in a plane perpendicular to the axis A can follow a circle, a polygon having a number of sides greater than or equal to five, a star with more than five branches, a curve close to the preceding curves, and in general, a curve which has no privileged dimensions. By way of example, the floating hull 49 may have a surface of revolution about the axis A. According to a meridian section in a plane containing the axis A, the floating hull 49 may have the transverse profile of the hull. a ship. The material used to make the hull 49 may be identical to the material used to make the hull of the current vessels.

The maximum diameter of the floating hull 49 may vary from 1.5 to 5 times the distance between the leading edges of the shrouds 22 of the stage 20 at the base of the turbomachine 12. The ratio between the height, measured according to FIG. axis A, and the maximum diameter of the floating hull 49 may vary from 0.5 to 5. Preferably, the floating hull 49 has an elongate shape and the ratio between the height, measured along the axis A, and the diameter maximum of the floating hull 49 can vary from 1.5 to 5.

The float 14 may comprise an upper bridge 50 and an intermediate bridge 52, below the upper bridge 50. In FIG. 3, the upper bridge 50 is shown with a frustoconical shape and comprises a cylindrical opening 51 of axis A. However, the angle of the truncated cone may be very small, for example less than a few degrees, so that equipment, including cranes, can be arranged on the upper deck 50. The space provided between the upper deck 50 and the deck Intermediate 52 constitutes a superior steerage 54. Steerage 54 may play part of the role of a storage. Control instruments, control, thermal control systems, air handling machines can be provided in the bridge 54 which then appears as a machine room. The upper steerage 54 may be at least partly below the water level 18.

The submerged part of the float 14 under the intermediate bridge 52 ensures the buoyancy of the wind turbine 10. The float 14 comprises another intermediate bridge 58, below the intermediate bridge 52, which delimits an intermediate mid-deck 60 with the intermediate bridge 52. The float 14 further comprises a lower bridge 62, below the intermediate bridge 58, which delimits with the intermediate bridge 58 a lower tweeter 64 at the lower end of the float 14. The heavy and bulky conversion bodies mechanical / electrical energy, in particular the generator 65, are located in the lower tweeter 64. A central cylindrical conduit 66, sealed, axis A connects the bridge 52 to the bridge 58. The conduit 66 opens at one end on the upper twister 54 and the opposite end on the lower tweeter 64. A fixed weight 68 may be provided below the lower bridge 62.

The mooring lines 16 connect the floating hull 49 to the seabed. The mooring lines 16 are flexible. At least three mooring lines 16 may be used. The mooring lines 16 can fan away from the floating hull 49 and are each fixed to the seabed by means of an anchor or a pile, not shown. The mooring lines 16 may be chains, steel cables, synthetic ropes, etc.

The turbomachine 12 is mounted on the float 14 so that the turbomachine 12 can rotate relative to the float 14 about a substantially vertical axis in a pivot-type connection. Preferably, the axis of rotation of the turbomachine 12 relative to the float 14 corresponds to the axis A. As a result, the holding structure 36 of the column 35 of turbines is pivotable relative to the float 14 around the axis A. The holding structure 36 of the turbomachine 12 is extended at the bottom and secured to a connecting structure 70, comprising an upper hollow cylindrical portion 72, of axis A, partially closed at the top by a flat plate 74 perpendicular to the axis A. The cylindrical portion 72 is extended in the lower part, via an annular portion 76, by a lower hollow cylindrical portion 78, coaxial with the cylindrical portion 72 and of smaller diameter . The cylindrical portion 72 is partially disposed in the upper tweer 54. The plate 74 is located at the opening 51 of the upper bridge 50. The cylindrical portion 78 extends in the conduit 66. The cylindrical portion 78 is provided a flange 80 at its lower end.

The plate 31 located at the base of the turbomachine 12 is, for example, fixed to the plate 74. A radial radial bearing 82 is provided in the deck 54 and allows the rotation of the upper cylindrical portion 72 relative to the floating hull 49 about the axis A. The bearing 82 is located above the hull center of the float 14 when the axis A is vertical.

A radial bearing is a bearing which prevents displacements of the shaft held by the bearing in a direction perpendicular to the axis of the shaft. A radial and axial sealed bearing 84 is provided in the tweezers 60 at the lower end of the cylindrical portion 78. The radial and axial bearing 84 is provided for example at the flange 80. The bearing 84 is located below from the float center 14 when the axis A is vertical. An axial bearing is a bearing which prevents the displacement of the shaft held by the bearing along the axis of the shaft. Bearings 82, 84 may include roller bearings, tapered one- or two-row bearings, plain bearings, and the like. Each bearing 82, 84 may comprise several bearings.

The float 14 comprises a transmission system 89 of the mechanical energy supplied by the column 35 of turbines to the generator 65. In the present embodiment, the transmission system 89 is essentially mechanical and comprises a drive shaft 90 of axis A. The rotation shaft 90 extends in particular in the cylindrical portions 72 and 78 and in the lower tweeter 64. The upper end of the shaft 90 is connected to the rotation shaft 32, not shown in Figure 3, the turbine at the base of the column of turbines. The lower end of the shaft 90 is connected to the generator 65. The column of turbines rotates the shaft 90 which, in turn, directly rotates the generator 65. The shaft 90 is held by a bearing radial and axial sealed 92 fixed to the plate 31 at the base of the turbomachine 12. The shaft 90 is further maintained by a radial and axial bearing 94 fixed to the lower bridge 62. Additional bearings, not shown, can be provided , for example in the conduit 66, for the maintenance of the shaft 90. The additional bearings located above the center of the hull may be only radial bearings.

The ballast 68 may be replaced by a flywheel driven by the shaft 90.

The generator 65, shown schematically in FIG. 3, comprises, for example, a rotor 96 driven directly in rotation by the shaft 90 and a stator 98 surrounding the rotor 96. It may be a direct drive magnet generator. permanent multipolar. It can also be a synchronous alternator with wound rotor. It can also be an asynchronous generator, a speed multiplier can then be provided between the shaft 90 and the rotor of the generator and / or between the shaft 90 and the shaft 32 of the turbine at the base of the column 35 of turbines. Electrical equipment 100 recover the energy supplied by the generator 65, which is transmitted by a cable 102.

In operation, the column of turbines rotates the shaft 90 which, in turn, drives the generator 65. The pivot type connection between the turbine engine 12 and the float 14 makes it possible to orient the turbomachine 12 in the direction of the wind to increase the efficiency of the turbomachine 12.

Figure 4 is a perspective sectional view of an embodiment of the float 14 of the wind turbine 40, only the base of the turbomachine 12 being shown. The plate 31 at the base of the holding structure 36 of each column of turbines is fixed to the plate 74. The axis of rotation of the turbomachine 12 with respect to the float 14 is parallel to the axes D and D 'of rotation of the two Turbine columns and preferably corresponds to the axis A. The float 14 of the wind turbine 40 shown in FIG. 4 has the same structure as the float 14 of the wind turbine 10 represented in FIG. 3 with the difference that the rotation shafts 32 at the base of the turbine columns are connected to the rotation shaft 90 via a transmission system 102, provided for example in the cylindrical portion 72, and not shown in detail. The transmission system 102 may be a mechanical transmission system. It may include gear trains, such as the system described in PCT / FR2008 / 051917.

FIG. 5 is a view similar to FIG. 3 of another embodiment of the float 14 which has the same structure as the structure of the float 14 shown in FIG. 3, except that the transmission system 89 which connects the shaft of rotation 32 of the turbine at the base of the column 35 of turbines and the generator 65 is a hydraulic system.

The wind turbine 10 comprises a hydraulic pump 110, for example of variable displacement, housed in the cylindrical portion 72, and driven by the rotation shaft 32. Pipes 112, 114 connect the hydraulic pump to a hydraulic motor 116 housed nearby of the generator 65. It may be a hydraulic motor 116 with variable displacement, for example a hydraulic motor 116 with gears. The hydraulic motor 116 rotates the rotor 96 of the generator 65.

According to another exemplary embodiment, when the shafts 32 of the turbines 30 of a column are independent of the each other and that each shaft 32 drives a hydraulic pump housed in the plate 31, the hydraulic pumps can be connected to the hydraulic motor 116.

Figure 6 is a perspective sectional view of an embodiment of the float 14 of the wind turbine 40, only the base of the turbomachine 12 being shown. The plate 31 at the base of the holding structure of each column of turbines is fixed to the plate 74. The float 14 of the wind turbine 40 shown in FIG. 6 has the same structure as the float 14 of the wind turbine 10 shown in FIG. 5 except that the rotation shaft 32 at the base of each column of turbines drives a hydraulic pump 117, 118. The hydraulic pumps 117, 118 are connected to a flow control system 119, itself connected to the suction and discharge conduits 112, 114. In operation, the two hydraulic pumps 117, 118 drive the hydraulic motor 116.

According to another exemplary embodiment, when the shafts 32 of the turbines 30 of the twin columns are independent of each other and each shaft 32 drives a hydraulic pump, housed in the lower plate 31, the hydraulic pumps can be connected to the hydraulic motor 116 .

The exemplary embodiments of the float 14 according to the invention described with reference to FIGS. 3 to 6 provide the static stability of the floating wind turbine 10, 40 with respect to horizontal displacements or tilting.

Indeed, the resultant F ^ substantially horizontal aerodynamic forces on the turbine engine 12, in the direction of the wind (drag) or perpendicular to the direction of the wind (lift), is exerted in an aerodynamic center A _r located in the turbomachine 12 The resultant F 1 is taken up by the mooring lines 16 which thus limit the movement of the wind turbine in a horizontal plane (movements of caval and yaw) as well as the yaw motions of the float 14. These aerodynamic forces can in addition to hydro- horizontal dynamics which are also taken up by the anchor lines.

Similarly, the buoyancy of Archimedes P, which is exerted in the center of the hull C of the float 14, and the sum of the weights of the float 14, mp, and the weight m ^ of the assembly formed by the turbomachine 12 extended by the connecting member 70, and wetting lines 16, which is exerted at the center of gravity G of the wind turbine, also located in the float 14, are substantially vertical and offset each other. The determination of the Archimedes thrust and therefore of the volume of the submerged hull 49 is constrained by the set of weights to be supported which are fixed in advance: turbomachine 12 and damping lines 16. Only the weight of the float 14 offers a margin maneuver knowing also that for issues of cost, the weight of material used should be reduced.

The action of the resultant F ^ on the turbomachine 12 is reflected on the float 14 via the upper bearings 82 and lower 84 located at points Pg and P _j . Advantageously, the bearing 82 is essentially a radial bearing while the bearing 84 is a radial and axial bearing. The bearing 84 is therefore the only one of the two bearings 82, 84 to absorb the axial loads related to the weight m ^ of the turbomachine 12, the connecting member 70 and the wetting lines 16. As a result, these loads s' apply essentially at level 84, in P _j , so that the center of gravity G of the wind turbine is in fact defined by the relation:

(m _F + m _T ) GC = m _F G _F C + m _T P _j C

where Gp is the center of gravity of the float 14 and where the distances, measured in the vertical direction, are signed, namely the distance signed EF is positive when the point F is above the point E and is negative when the point F is below the point E. On the one hand the positioning of the location P _j of the lower bearing 84 below the hull center C promotes the lowering of the center of gravity G below the center of hull C. On the other hand, the organs heavy and bulky power conversion Mecani ^¬ / electric, in particular the generator 65, arranged at the lower end of the submerged part of the float 14 in the lower decks 64, contribute to lowering the position of the center of gravity Gp float below the hull center C and also favor the lowering of the center of gravity G below the center of hull C. However, as we will see later, the increase in the distance signed GC is favorable to the stability static of the wind turbine 10, 40.

It is placed in a meridian plane of the float 14 containing the resultant aerodynamic forces F ^ not to distinguish in the following between drag and lift as well as between moment of roll and moment of pitch, grouped under the term of tipping moment mg. The radial bearing 82 takes up part of the bending forces applied to the turbomachine 12 and the same is true of the radial and axial bearing 84. To keep the floating wind turbine 10, 40 in a perfectly vertical position when a tilting moment s it is shown that the radial reaction Rg of the upper bearing 82 must be:

% = -d + A _r P _S / PiP _S ) F _A

and the radial reaction Rg of the lower bearing 84 must be:

The further away the bearings 82, 84 are from the other, the longer the hull 49 is elongated and the more the bearings 82, 84 are relieved and the greater part of the reaction is provided by the upper bearing 82 which must be placed as close as possible to the plate 74.

Under the effect of the tilting moment Μ _β resulting from the resultant aerodynamic forces F _i which reaches a maximum value in P _j , the wind turbine tends to tilt by an angle Θ. This moment must be compensated to bring back the axis A in the vertical direction. The moment of recovery M results from a triple effect. The first effect is related to the fixing point of the anchoring lines 16. In order to better compensate for the tilting moment Mg which reaches a maximum value in P _j , it may be advantageous for the anchoring lines 16 to be connected to a position L such that the distance A _r L is minimized and, the distance A _r Pg being given elsewhere, such that the distance LPg is as small as possible. This implies that L is in an upper position of the shell 49, that is to say in a position as shown by way of example in FIG. 2. On the other hand, the wetting lines 16 being heavy, it is advantageous to fix them in a lower position: a compromise is to be found.

The other two effects are expressed in the following formula:

M _R = P x (CH + GC) x sin Θ

The first term translates the lateral displacement of the center of careen C which deviates from the axis of symmetry A of the floating hull 49. To introduce this displacement is introduced the metacentric point H located above C at a proportional distance in the case considered at the ratio of the square of the radius of the floating hull 49 on its height, if one assimilates the hull to a disk. To amplify this effect, it is necessary to expand radially shell 49 and shorten the axial elongation. It is this stabilizing effect that is favored in multifunctional wind turbines that have a wide base.

The second term reflects the effect implemented in the physics apparatus called ludion. This effect assumes, of course, that the center of gravity is located below the hull center of the float 14. It is this stabilizing effect which is favored on the contrary in wind turbines with submerged weights housed in the bottom of thin and elongated structure ( in English SPAR). This effect is also favored by the embodiments described above, without the first effect being neglected. So as announced above, the increase of the distance signed GC is favorable to the static stability of the wind turbine 10, 40. The elongation of the floating hull 49 offers a greater latitude to increase both the distances GC and PjPs / which makes ^it possible both to amplify the rectifying torque and to relieve the radial bearings .

In conclusion, compared to an axial flow turbine:

the proximity of the upper deck 54 of the sea surface 18 causes the weight of the elements arranged in the upper deck 54 to cause a negligible moment of tilting of the wind turbine 10, 40.

energy conversion components Mecani ^¬ / electrical (generator 65 and the electrical equipment 100) of the wind turbine 10, 40 are located below the wind center of gravity 10, 40. The weight of the conversion components mechanical / electrical energy no longer favor the tilting of the wind turbine 10, 40.

Access and maintenance of the wind turbine 10, 40 is simplified. Indeed, as the upper high deck 54 is at the foot of the turbomachine 12 above the water level 18, the access and the evacuation of the bridge 54 can be made simply by traps. The presence of the sea in the vicinity of the steerage deck 54 also dampens the temperature differences at the level of the steerage deck 54. It is therefore possible not to provide for thermal regulation systems in the steerage deck 54. alternatively, it is possible to provide thermal control systems using seawater that is easily accessible. In addition, the access to the generator 65 which is located in the hull 49 is facilitated, for example by the tweeter 60.

In addition, for the embodiments described above in relation to FIGS. 3 and 4, the stresses exerted on the generator 65 are reduced. In fact, the shaft 90 transmits to the generator 65 the sum of the torques delivered by the turbines of the turbine column without the bending stresses and the constraints along the axis D which are taken up by the holding structure 36 of the turbomachine 12 and transmitted to the floating shell 49 via the connecting structure 70. Therefore, the design of the generator 65 can be simplified. In particular, in the case where the generator 65 is direct drive and permanent magnets, it is easier to maintain the play of the gap of the generator in the ranges necessary for the proper operation of the generator 65.

In addition, for the embodiments described previously with reference to FIGS. 3 and 4, the drive shaft 90 directly connects the column of turbines to the rotor of the generator 65. As a result, the moment of inertia of the rotor is high. On the one hand, a large gyroscopic effect thus contributes to further stabilizing the axis A of the float 14 in the vertical direction. On the other hand, a smoothing of the rotational speed of the rotor of the generator 65 is obtained.

According to the embodiments described above in connection with FIGS. 5 and 6 and according to the exemplary embodiment in which each turbine 30 drives a hydraulic pump, the use of a hydraulic transmission system 89 allows the implementation of different types of servo-control between the pump 110 or the hydraulic pumps 117, 118, 120, 122 and the hydraulic motor 116, for example to protect the turbomachine 12 against the jolts of operation due to gusts of wind or to provide a function of braking in case of emergency stop.

FIG. 7 represents another exemplary embodiment of a wind turbine 150. The wind turbine 150 has a structure similar to the wind turbine 10 shown in FIG. 1, with the difference that the floating shell 49 comprises a portion of reduced section 152, forming a collar. or constriction, at the level of the float water line 14. The waterline 153 is shown in dashed lines in FIG. 7 and corresponds to the line which separates the submerged part of the floating hull 49 from the emergent part of the floating hull 49. The collar 152 makes it possible to reduce the impact of the waves on the floating hull 49.

In addition, the floating hull 49 can be fixed to the seabed 154 by a stretched line 156 which connects the lowest point 158 of the floating hull 49 to an anchoring system 160 fixed to the seabed 154. The line 156 is stretched permanently. Line 156 may be composed of one or more tendons which may include steel pipes, metal cables ^¬ lic or cords of synthetic fibers or a combination of these materials. Line 156 advantageously makes it possible to reduce the heave movements of float 14 without having to contribute to the limitation of horizontal displacements, which is the objective assigned to the waterlines 16. For this, the pretension of line 156 can be reduced thus relieving the overall downward force that must overcome the float through the force of Archimedes. The rigidity of the line 156 can also be reduced resulting in the use of less material on the one hand and on the other hand avoiding the decrease in the proper period of heave which must remain important as explained below.

FIG. 8 is a diagrammatic section of the float 14 of the wind turbine 10, 40 described above in relation to FIGS. 1 to 7 in a plane perpendicular to the axis A at the level of the steerage 60. The steerage 60 may be divided into compartments 160 separated by bulkheads 162 substantially vertical. Each partition 162 extends between the floating hull 49 and the duct 66 over the entire height of the tweeter 60. By way of example, eight compartments 160 are shown in FIG. 8. The float 14 may comprise a filling device 164. and selectively emptying the compartments 160 independently of each other in seawater. The device 164 may provide a means for adjusting the pitching and rolling periods of the floating hull 49. These periods must be outside the range of periods of excitation of the waves which are the most energetic. This dangerous range can typically be between 20 and 25 seconds. The proper periods of pitch and roll increase with the moments of conventional inertia and inertia added around the roll and pitch axes respectively. They decrease with the stiffness in rotation of the wind turbine which is quantified by the righting moment M _R and that one sought above to maximize to increase the static stability. If we try to fix the proper periods of roll and pitch just above the dangerous range, ie 30 seconds for example, we must choose the aforementioned sufficiently large moments. This can be done by lengthening the floating hull 49. One can also play on the distance of the compartments 160 of the axis A of the hull 49 during the design and on their selective filling by favoring the compartments 160 close to the plane perpendicular to the axis A around which the moment of inertia must be amplified. Finally a compromise to reduce the righting moment M _R without sacrificing the constraints of the static stability can also be sought.

The proper periods of pitching and rolling must also be removed from heave periods in order to avoid the coupling of these movements. As the Archimedes' thrust is fixed, the proper period of heave decreases with the flotation surface (section of the floating hull 49 at the waterline 153). The portion 152 of reduced section shown in Figure 7 can amplify this period well beyond the proper periods of pitching and rolling. On the contrary, it can be set at a value lower than the dangerous range (below 10 seconds) by keeping the same diameter or by increasing the rigidity of the pretension line

156.

Particular embodiments of the present invention have been described. Various variations and modifications occur to those skilled in the art. In particular, exemplary embodiments of floating wind turbines comprising one and two Turbine columns have been described. However, it is clear that the invention can be implemented for floating wind turbines comprising more than two columns of turbines. Various embodiments with various variants have been described above. It is noted that one skilled in the art can combine various elements of these various embodiments and variants without being creative. In particular, although the wind turbine 150 is shown in Figure 7 with a throttle 152 and a tension line 156, it is clear that the throttle 152 and the tension line 156 can be provided independently of one another.

Claims

A floating wind turbine (10; 40) comprising a float (14) and a turbomachine (12) resting on the float, the float comprising a floating hull (49), the turbomachine comprising at least one column (35) of turbines (30). ) with a transverse flow and a holding structure (36) of the turbines, the holding structure being extended by a connecting member (70), located in the floating shell and connected to the floating shell in a pivot connection by at least first and second bearings (84, 82) located in the floating hull, the first bearing (84) being located below the hull center of the hull, the turbine comprising a turbine-driven generator (65) and located in the floating hull under said hull center.

A floating wind turbine (10; 40) according to claim 1, wherein the connecting member (70) extends over more than half the height of the floating hull (49), the second bearing (82) being located above said center of hull, the second bearing being a radial bearing and not being an axial bearing and the first bearing (84) being a radial and axial bearing.

Floating wind turbine according to claim 1 or 2, wherein each turbine (30) comprises a drive shaft (32), the turbine drive shafts of the column (35) being connected to each other, the connecting member (70) comprising a transmission system (89) connecting, to the generator (65), the drive shaft of the turbine at the base of the column.

A floating wind turbine according to claim 3, wherein the transmission system (89) comprises a link drive shaft (90) connecting the turbine drive shaft (32) to the generator (65). (30) at the base of the column (35).

The floating wind turbine according to claim 3, wherein the transmission system (89) comprises a hydraulic pump (110; 117,118) driven by the drive shaft. The hydraulic pump is connected to a hydraulic motor (116) driving the generator (65).

6. A floating wind turbine according to claim 3, wherein the turbomachine (12) comprises a column (35) of additional turbines (30) transverse flow, the drive shafts (32) of the turbines of the additional column being connected together to others, the transmission system (89) further connecting to the generator (65), the drive shaft of the turbine at the base of the additional column.

7. A floating wind turbine according to any one of claims 1 to 6, wherein the floating hull (49) is rotationally symmetrical and has, in a meridian plane, the transverse profile of the hull of a ship, the ratio between the height of the floating hull and the maximum diameter of the floating hull varying from 1.5 to 5.

8. A floating wind turbine according to any one of claims 1 to 7, wherein the float (14) comprises compartments (160) and a device (164) for filling and emptying water of each compartment independently of each other.

9. A floating wind turbine according to any one of claims 1 to 8, wherein the float (14) comprises at least a first steer (54), a second steer (60) under the first steer, a third steer (64) under the second steer, and a conduit (66) passing through the second steerage and connecting the first steer to the third steerage, the generator (65) being located in the third steerage, the holding structure (36) being connected to the float by the first and second bearing (84, 82), the second bearing (82) being in the first steer, the first bearing (84) being in the third steer or in the conduit, closer to the third steer than the first steer.

10. A floating wind turbine according to any of claims 1 to 9, wherein the floating hull (49) has a reduced section (152) at the water line (153).

11. A floating wind turbine according to any one of claims 1 to 10, comprising unsprung anchoring lines (16), radiating from the floating hull (49) and intended to connect the float (14) to the seabed (154) .

Floating wind turbine according to any one of claims 1 to 11, further comprising a tension line

(156) connected to the lowest point of the float (14) and intended to be connected to the seabed (154).

13. A floating wind turbine according to any one of claims 1 to 12, wherein the holding structure (36) comprises, for each turbine (30), vertical uprights (22, 42) on either side of the turbine and at least one horizontal plate (31) fixed to the vertical uprights (22, 42), the turbine being connected to the horizontal plate by a pivoting connection (34).

Floating wind turbine according to claim 13, in which each turbine (30) comprises a drive shaft (32), the turbine drive shafts not being connected to each other, each drive shaft being connected to each other. to the generator (65) by a hydraulic transmission system comprising a hydraulic pump located in the plate (31).