FR2964422A1 - WINDMILL WITH ALTITUDE REGULATION ACCORDING TO AERODYNAMIC FORCES. - Google Patents

Abstract

The present invention relates to a wind turbine with altitude regulation according to the aerodynamic forces, in particular to allow the regulation of the power captured by the wind turbine. The invention relates to displacement means comprising a lever equipped with a counterweight and connected by means of connection to a tilting support arm of the wind turbine so as to recall the carrier arm upwards. The displacement means moves the connecting means and the counterweight on the lever so as to raise the carrier arm upwardly as the carrier arm lowers.

Description

"Wind turbine with altitude regulation according to the aerodynamic forces"

The present invention relates to a wind turbine with altitude regulation and orientation according to the aerodynamic forces, in particular to allow the regulation of the power captured by the wind turbine. According to a second aspect of the invention, displacement means make it possible to adjust the inclination of a support arm particularly for maintenance and / or protection in the event of strong winds.

According to a third aspect of the invention, a braking device makes it possible, under the action of the wind, to reduce the power captured in the event of strong winds. The invention relates to wind turbine applications of any kind, in particular for the production of electricity, or mechanical applications such as pumping. The invention is based on the observation that the aerodynamic forces generated by the wind decrease as one approaches the ground. The wind power captured by the rotor therefore decreases as the rotor approaches the ground.

On the same site, winds can vary greatly depending on weather conditions. This is why wind turbines generally have regulating devices that make it possible to exploit wind energy over a widest range of wind speeds, but also protection devices intended to prevent any degradation of the wind turbine in the event of strong winds. . Classically, wind turbines include a wind group placed at the top of a fixed mast to maximize the wind power captured. To be able to make the most of winds whose aerodynamic force varies over time, and / or to face strong winds, a wind turbine generally accumulates different control systems. These control systems can be of different types, particularly electrical, for example the use of synchronous electric generators, mechanical for example using a disk brake acting on the rotor, aerodynamic for example using stepped blades adjustable.

In addition to the high cost they represent, this equipment contributes to the significant weight of the wind group, which also adds additional costs of implementation. The maintenance of wind turbines whose wind group is placed at the top of a mast is tricky: either the technician and his equipment must be allowed to climb to the level of the wind farm, or have a crane to lower the wind group to the level of the wind farm. of the ground. According to FR2823784 a wind turbine with a guyed mast and hinged at its base to allow to lower the wind turbine to the ground by means of a winch equipping one of the stay cables. Lowering or raising the wind turbine takes about one hour. This solution makes it possible to use a thin mast generating less aerodynamic disturbances, to facilitate maintenance and to protect the wind turbine in the event of a storm. Regulation of the wind power captured is provided by conventional control means of the kind previously described. In wind turbines according to WO 90/03517, a mast supports a support arm in a median region thereof. The wind group is suspended at one end of the arm, a counterweight is suspended at the other end. When the wind becomes more intense, the aerodynamic forces lower the wind group to the ground, and the counterweight rises accordingly. In a first embodiment, this is obtained by variable inclination of the arm about a horizontal axis relative to the top of the mast. In another embodiment, the wind generator and the counterweight are attached to both ends of a cable that runs along the non-reclining arm. In both cases a mast of a certain height is necessary. This mast, as well as the foundations that support it in the ground, are exposed to considerable moments, generated by aerodynamic forces, especially those captured by the wind group. This results in a delicate and expensive construction, and heavy components. In addition, the regulation of the known device is operative only for a relatively narrow range of wind speeds. In addition, the known structure does not always allow fine regulation of the power captured for each wind force. A first objective of the invention is to propose a wind turbine with optimized inclination regulation of a support arm.

A second object of the invention is to propose a wind turbine whose structure is less mechanically constrained. A third object of the invention is to provide a wind turbine in which an arm supporting the wind group is tiltable about an axis close to the ground. The invention also aims at a low cost wind turbine, particularly suitable for the production of small units. Another objective of the invention is to propose a wind turbine with adjustable inclination of a support arm, in particular for maintenance and / or protection in the event of strong winds. The invention proposes a wind turbine comprising: - a support arm having an articulated portion which is hinged relatively to the ground with freedom of rotation in inclination and azimuth, - at least one wind group connected to a movable portion of the support arm, located at a distance of the articulated portion, so that the aerodynamic forces experienced by the wind group tend to pivot the carrier arm downward in a plane of inclination parallel to the wind direction and decrease the altitude of the wind group; a force generator, in particular a counterweight, for producing a return force; balancing means for converting the return force into a moment of return of the carrier arm upwards, the balancing means comprising adjustment means responsive to the inclination of the carrier arm to vary the moment of recall in the opposite direction of the altitude of the wind turbine group, a lever being at least indirectly in transmission of restoring force transmission relationship with the support arm, characterized in that the balancing means form with the support arm a structure with adjustable geometry and in that the adjusting means controls an adjustment of said geometry.

This architecture makes it possible to change the return force according to a predetermined law when the inclination of the arm varies. The invention thus makes it possible to better control the inclination of the carrier arm as a function of the aerodynamic forces, and thus to improve the regulation of the wind turbine. The use of an increasing return moment as the carrying arm lowers also makes it possible to eliminate the instability phenomena of the wind turbine by oscillation in inclination.

According to another important aspect of the invention, the balancing means comprise a lever of the balancing means having a hinge means conferring an adjustable inclination and a connecting means to the force generator, the lever being at least indirectly in the transmission of restoring force transmission relationship with the carrier arm characterized in that the adjustment means move the connecting means relative to the hinge means. As the variation of the moment of return is no longer necessarily obtained by movements of a counterweight moving with a rear portion of the support arm, the arm can be hinged close to the ground. The invention also proposes that the connection means comprise a sliding carriage along the lever, the force generator being connected to said carriage. In one embodiment of the invention, the balancing means comprise: the lever having a hinge means giving it an adjustable inclination and a retaining means, the force generator acting on the lever; - A return force transmission member at least indirectly connecting the retaining means and the support arm, and the adjusting means comprise displacement means for moving the retaining means on the lever. The invention also proposes that the balancing means comprise the lever that can be pivoted by means of articulation and carrying means for connecting the force generator and a retaining means, as well as a reminder force transmission member. at least indirectly connecting the support arm and the retaining means. The adjustment means comprise displacement means for moving at least one of the hinge, connecting and retaining means relative to the other two.

In one embodiment, the displacement means move the connecting means and the retaining means in opposite directions of the other along the lever. The invention also proposes that the displacement means comprise a coupling cable forming a loop stretched between two diverting pulleys carried by the lever, the connecting means and the retaining means being each connected to a respective one of two opposing strands. of said loop, so as to move in opposite directions the connecting means and the retaining means on the lever. The relative displacement of the connecting means and the retaining means along the tilting lever varies the return force transmitted to the support arm by the retaining means. The moment of return can thus be increasing when the carrying arm lowers. The invention thus allows better control of the altitude of the wind group, and therefore a better regulation of it. According to a further aspect of the invention, the return force transmission member is a cable whose length is adjustable by a winch for bringing the carrier arm lying down for maintenance or in case of storm. The winch makes it possible to vary the length of the at least one return force transmission member linking the support arm to the lever, and thus to adjust the inclination of the carrier arm of the wind turbine. In particular, it is possible to incline the support arm so as to place the wind generator close to the ground, which makes it possible in particular to facilitate maintenance operations and / or protection in the event of strong winds. The winch makes it possible to train the wind turbine without the need for a crane. The wind turbine can thus be assembled beforehand on the ground, which is convenient and economical. The winch could for example be mounted on the retainer. But preferably, it is installed near the ground, and the cable extends from the winch of the carrier arm through a pulley belonging to the retaining means. Thus the winch is at man's height for maintenance operations and / or to be maneuvered. Preferably, the cable extends over a stop on which it rests when the support arm is in the supine position. Thus, even when the arm is inclined downwards, especially in the supine position, the cable forms an angle with the support arm. The carrier arm can be brought back to the service position by pulling on the cable, in particular with the winch. The invention also proposes that the adjustment means comprise a leg articulated at least indirectly: on the one hand relatively to the ground away from the lever; - on the other hand by means of restraint.

The aforementioned winch can be secured to the leg. Thus, when the winch is not actuated, the length of the at least one return force transmission member may be constant between the support arm and the lever regardless of their respective inclination. In combination or separately, it is advisable to place the winch at man's height for maintenance operations and / or to be maneuvered as already envisaged above.

According to a complementary aspect of the invention, the retaining means comprises a retaining carriage slidably mounted along the lever for moving the retaining means on the lever. The invention further proposes that the lever is orientable about a vertical axis to be substantially in the same vertical plane as the carrier arm. According to an important aspect of the invention, the articulation means of the lever is placed higher than the articulated part of the support arm, in particular substantially above the articulated part. Preferably, the mast is rotatable around a vertical axis relative to the ground. The invention further proposes that the mast is equipped with a stop near the articulation to the lever in order to maintain the return force transmission member, made flexible, above the stop. The wind turbine preferably comprises a turret which is rotatable about a vertical axis relative to the ground and to which the support arm is articulated about a horizontal inclination axis. The lever and / or the leg can also be carried by this turret and articulated along one or more horizontal axes relative thereto. The wind turbine preferably comprises as an electric generator an asynchronous three-phase motor. The asynchronous three-phase motor has a reduced cost, in particular a lower cost than the generators usually used. In addition, an asynchronous three-phase motor is widely available on the market, its maintenance is easy, its relatively low weight facilitates tilting movements of the carrier arm of the wind turbine. The wind turbine group preferably comprises at least one rotor consisting of a circular rim connected to a hub by spokes, webs being stretched between the spokes and anchors to the rim. This rotor structure has a great ease of implementation, and a low cost.

A driven shaft, in particular that of an electric generator, is preferably driven by the rotor by means of at least one belt wound at least partially around the rim. The rim also participates in power transmission and transmission ratio, reducing the number of parts required. This decreases the weight and cost of the wind turbine. According to another aspect of the invention, the hinge means is placed higher than the articulated portion of the support arm, and in particular articulates the lever to a mast with freedom of rotation in inclination. Preferably, the mast is associated at least indirectly with the ground while being connected in rotation in azimuth with the support arm. The return force depends on the action exerted by the counterweight on the lever under the action of gravity. For a given position of the counterweight along the lever, the counterweight moment tends to increase as the lever approaches a horizontal position. By raising one end of the lever, the lever is allowed to be in a non-horizontal initial position when the wind group is in the up position, and to tend towards a substantially horizontal position when the altitude of the wind group decreases (stronger wind). . The moment of the counterweight can then grow as the inclination of the lever tends to the horizontal position, allowing a better regulation of the wind turbine. According to an important aspect of the invention, the wind turbine group comprises at least one braking device. In particular, the braking device makes it possible to prevent any deterioration of the wind turbine due to excessive winds and / or in the event of at least partial malfunction of the wind turbine. Preferably the braking device comprises a braking pad, pivoting at least temporarily around a pad axis so that the aerodynamic forces exerted on the pad tending to rotate the pad to a braking activation position . The braking device thus allows braking proportioned to the aerodynamic forces without requiring external operation. The invention also proposes that the wind generator is associated with the support arm by a pivot connection, or temporary pivot having an axis oriented along the normal plane of rotation in inclination of the carrier arm.

The invention thus makes it possible either to maintain the rotor in a substantially vertical position, in particular under the action of gravity, or to incline the rotor at the same time as the support arm. A rotor held substantially vertical will on average capture more wind power than a tilting rotor. The tilting rotor forms an angle relative to the wind as the carrier arm tilts, thereby reducing the aerodynamic forces exerted by the wind on the wind turbine, as well as the energy captured by the rotor. Other features and advantages of the invention will appear on reading the following description relating to non-limiting embodiments. In the accompanying drawings: FIG. 1 is a perspective view of the wind turbine in the up position according to the invention, FIG. 2 is a side view of the wind turbine of FIG. 1 in the high position, FIG. is a side view of the wind turbine in the down position, - Figure 4 is a side view of the wind turbine in the storm position, and - Figure 5 is a perspective view of the wind turbine with braking of the braking unit .

The wind turbine shown in the figures comprises (see FIG. 1) a wind energy group 1 intended to capture wind energy and transform it into useful energy, typically into electrical energy. The wind turbine group 1 is carried by a carrier arm 2 at a variable altitude relative to a bearing surface 3 (see FIGS. 2 to 4). In the remainder of the description, it will be considered that the carrier surface 3 is the floor.

The carrying arm 2 comprises a portion 4 articulated relative to the ground 3 about a substantially horizontal axis of inclination 6, and a movable portion 7 to which the wind power unit 1 is connected. In the example shown, the articulated portion 4 and the movable portion 7 respectively correspond to a proximal end and to a distal end of the support arm 2.

Advantageously, the articulated portion 4 and the hinge pin 6 are substantially adjacent to the ground 3. The support arm 2 is movable about the hinge axis 6 between a high, quasi-vertical position (see FIGS. and 2) in which the altitude of the wind turbine group 1 and the mobile part 7 of the support arm 2 is maximum, and a low service position (FIG. 3) in which the wind turbine group 1 and the mobile part 7 of the support arm 2 are at a short distance above the ground 3.

In use, the wind subjects the wind group 1 to essentially horizontal aerodynamic forces which are transmitted to the support arm in the form of a moment which tends to incline the support arm towards the low service position, thus bringing the wind group closer to the ground.

Balancing means 8 are provided to balance variably this loading of the support arm by the aerodynamic forces, in the sense of a regulation of the altitude of the wind group 1 as a function of the force of the wind, so that the group wind turbine 1 is at high altitude when the wind is weak and at a lower altitude the lower the wind is stronger.

The aerodynamic forces exert on the support arm 2, around the axis of inclination 6, a moment tending to increase the inclination of the support arm 2 towards the ground 3, and the balancing means exert on the carrying arm, around of the inclination axis 6, a return moment, directed in the opposite direction, tending to reduce the inclination of the support arm 2 towards the ground 3.

These balancing means comprise a force generator, here a counterweight 9. The counterweight 9 indirectly biases the support arm 2 in the direction of pivoting from the low service position to the high position. In the example, this bias is transmitted by at least one cable 11 having an end 12 attached at least indirectly to the support arm 2 at a distance from the articulated part 4, here in the region of the mobile part 7. The at least one cable 11 extends above the axis of inclination 6. Said at least one cable exerts on the support arm 2 the aforementioned balancing moment tends to reduce the inclination of the support arm 2 towards the ground 3 around the inclination axis 6.

In the example, there are two cables working in parallel, which are attached to two opposite lateral regions of a transverse frame 13 of the wind group 1, so that the cables simultaneously perform a guying of the connection between the group. wind generator 1 and the support arm 2. The force produced by the force generator 9 is transmitted to the at least one cable 11 by a conversion device 14 comprising a lever 16 hinged relative to the ground 3 around a lever axis Parallel to the axis of inclination 6. The lever 16 carries means 18 for retaining the cable and means 19 for connecting the force generator 9. The force generator 9 biases the lever 16 via the connecting means 19, and the lever 16 in turn urges the at least one cable 11 through the retaining means 18 of the cable 11.

The lever shaft 17 allows in particular to articulate the lever 16 relative to the support arm. In the example shown, the lever shaft 17 is placed at a distance above the hinge axis 6, and in particular at the top of a mast 21. The assembly is such that the lever 16 is inclined downwardly from the lever axis 17 when the support arm 2 is in the up position (FIG. 2) and the lever 16 is substantially horizontal or even inclined upwards from the lever axis when the support arm 2 is in the low service position (FIG. 3). The balancing means comprise variation means 22 responsive to the inclination of the support arm 2 to vary the moment of return in the opposite direction of the altitude of the wind group 1. In the example shown, the means of variation 22 are means for adjusting the geometry of the balancing means and more generally the geometry of the assembly formed by the balancing means and the support arm 2. A first means for adjusting the geometry is a means for moving the means 19 for connecting the counterweight 9 relative to the lever 16. More particularly here, the connection means 19 move along the lever 16. For this purpose, the connecting means 19 comprise a connecting carriage 23 which is sliding along of the lever 16 and which is suspended the counterweight 9. When the connecting carriage 23 moves along the lever 16, the moment exerted by the counterweight 9 on the lever 16 varies. This causes a variation in the voltage of the at least one cable 11 and therefore a variation in the moment of return. A second means for adjusting the geometry is a means for moving the retaining means 18 of the at least one cable 11 relative to the lever 16. More particularly here, the retaining means 18 move along the lever 16. this effect, the retaining means 18 comprise a retaining carriage 24 which slides along the lever 16 and which supports the at least one cable 11. When the retaining means 18 moves along the lever 16, the tension in the at least one cable 11, induced by the moment exerted by the counterweight 9 on the lever 16, varies. In the example shown, the two adjustment means are coupled in such a way that the two carriages 23, 24 move in opposite directions along each other along the lever 16. For this purpose, a coupling cable 26 mounted in loop bypasses two diverting pulleys 27, 28 each located at one respective end of the lever 16. This cable 26 thus comprises two strands 29, 31 circulating in opposite directions along the lever 16. Each of the strands 29, 31 is coupled to one of the carriages 23, 24 respectively so that any movement of one of the carriages 23, 24 along the lever 16 is accompanied by a movement of the same length, but in opposite directions, of the other carriage 24, 23 along the lever 16. The two carriages 23, 24 are mounted to be able to cross along the lever 16. In the example shown, the two carriages 23, 24 are slidably mounted on two opposite longitudinal edges 32, 33 16. When the support arm 2 is in the up position (see FIG. responding to a low wind situation, the retaining means 18 of the at least one cable 11 are in an extreme position at most away from the lever axis 17 while the connecting means 19 are substantially halfway through. distance between the retaining means 18 and the lever axis 17. Therefore, the moment exerted by the counterweight 9 on the lever 16 is relatively small. In addition, the tension in the at least one cable 11 is low for two cumulative reasons: the relatively low moment of the counterweight 9 and the large distance between the retaining means 18 and the lever axis 17. In the low position of 3, corresponding to a situation of strong wind, the situation has substantially reversed, the connecting means 19 of the counterweight 9 is in an extreme position close to the free end of the lever 16 while the means of 18 of the at least one cable 11 is substantially located midway between the connection means 19 of the counterweight 9 and the lever axis 17. The return moment exerted by the counterweight 9 is increased, in particular substantially doubled relative to the situation of FIG. 2, and the tension in the at least one cable 11 is further increased, in particular substantially multiplied by 4, for two reasons: the increase in the moment of return exerted by the counterpoise s 9 and the approximation between the retaining means 18 and the lever axis 17. The means of variation are sensitive to the inclination of the support arm 2 to vary the moment of return in the opposite direction of the altitude of the wind group 1, and more particularly, in the example shown, to move the connecting means 19 and the retaining means 18 in the manner described above when the wind varies. In the example shown, this automatic adjustment function is mainly provided by a leg 34 articulated at least indirectly: on the one hand relatively to the ground 3 at a distance from the lever axis 17; - On the other hand the retaining means 18. Preferably, the two joints 36, 37 of the leg 34 are located at both ends. In the example shown, the hinge 36 of the leg 34 relative to the ground 3 is located near the base of the mast 21. It is also located near the axis of inclination 6. For articulation with the means 18, the leg 34 is articulated to the holding trolley 24. Thus, as seen by comparing Figures 2 and 3, the leg 34 moves the trolley 24 to the free end of the lever 16 when the lever 16 swivels down. The coupling cable 26 causes the connecting means 19 of the counterweight 9 to move in opposite directions in the opposite direction. Thanks to the adjustment means, there is a position of the retaining means 18 and the connecting means 19 which respectively correspond to each inclinations of the support arm 2, the tension in the at least one cable 11 being all the greater as the inclination of the support arm 2 towards the ground is strong. Thus, for each force of wind, the wind group 1 stabilizes at an altitude which is even lower than said force is large. The wind turbine is self-orienting in azimuth, that is to say around a vertical axis 38 which, in the example shown, coincides substantially with the axis of the mast 21 (see Figure 2). For this purpose, the articulation of the support arm 2 along the axis of inclination 6 articulates the support arm 2 with a turret 39 rotatably mounted relative to the ground 3 about the vertical axis 38. This turret 39 also carries the mast 21 and the articulation of the leg 34 relative to the ground 3. More generally, according to an important aspect of the invention, the articulated portion of the support arm 2 is connected to the ground 3 by a ball joint which, in the example described, is constituted by the combination of the articulation along the axis of inclination 6 and the pivoting mounting of this joint around the vertical axis 38 thanks to the turret 39. Still as in the example shown, this ball joint, and in particular its horizontal axis, namely the axis of articulation 6 in the example, is close to the ground 3. The freedom of movement of the movable part of the support arm around this ball joint is such that in all circumstances wind forces aerodynamic training on the wind group Iien place it in substantially optimal position for power capture, this by pivoting the carrier arm around the ball joint, and with the regulation provided by the balancing means with respect to the tilt component of the movement of the carrier arm.

Whatever the altitude of the wind group 1, the centroid of the aerodynamic forces acting on the wind group 1 is always located at a certain distance from the vertical axis 38. Thus, the aerodynamic forces exert on the wind turbine a moment of rotation about the vertical axis 38, constantly reminding the wind turbine in an azimuth where the resultant aerodynamic forces intersects the vertical axis 38. In the example shown, the support arm 2 forms a fixed angle with the plane of rotors (which will be described later), so that this plane is substantially vertical when the support arm is in the up position (Figure 2), and that this plane is all the more inclined as the inclination of the support arm 2 to the soil 3 is large (Figure 3). Thus, when the wind is strong (Figure 3), the area of the section of the wind vein intercepted by the rotors is smaller. In the preferred example which is shown, the wind generator 1 is articulated relative to the support arm 2 around an axis (not shown) parallel to the inclination axis 6 to allow the adjustment of the inclination of the plane of the rotors. relative to the support arm 2. The inclination thus set is fixed by a monitor 40 installed to be in tension under the action of aerodynamic forces acting on the wind group 1 and under the action of the weight of the wind group that tends to orient the plane of the rotors substantially vertically.

As shown in FIG. 4, the support arm is furthermore capable of a supine position, even more inclined than the low service position, and in which the aeolian group 1 is accessible from the ground 3. This position is useful for the maintenance of the wind group 1 by a person or a team intervening from the ground. This position is also useful in case of storm, to put the wind turbine completely out of service.

In the example shown, to allow this position, the at least one cable 11, instead of having an end attached to the holding carriage 24, bypasses the retaining carriage at least one pulley 41 and extends to the trolley 24 to a winch 42 located substantially on the ground 3 so as to be able to control it from the ground. More particularly, the winch 42 is located on the leg 34. Thus, when the winch is located on the leg 34, the movements of the leg 34 around its joints 36, 37 do not induce parasitic variations in the length of the cable between the retainer carriage and carrying arm. Even more particularly the winch 42 is located near the articulated portion 4 of the support arm 2. In the example shown, this extension of the at least one cable runs along the leg 34. To pass the support arm 2 in the supine position, the winch 42 is actuated in the direction of the elongation of its unrolled length.

The lengthening of the length unwound by the winch also makes the lever 16 in its maximum downward inclination position, the retaining means 18 are in their far extreme position at the maximum of the lever axis 17. It this is the position producing a reduced return moment, which can be substantially canceled if the counterweight is resting on the ground. In the example shown, the support arm reaches the supine position when the winch 42 has unwound the cable 11 over its entire length. There are on both sides of the upper end of the mast 21 two opposite stops 44 which prevent the cable 11 from being placed in this region lower than the top of the mast 21. Thus, the cable extends with a certain upward angle from the support arm 2 in supine position and actuation of the winch 42 in the direction of the winding of the cable 11 will effectively exert a lifting moment on the support arm 2.

The wind power unit 1 comprises at least one rotor 51 and an electric generator 52 mounted on the transverse frame 13. The wind power unit being placed at the top of the support arm 2, the electricity can then be brought to the ground via minus an electric cable not shown. Different types of electric generators can be used. The wind turbine according to the invention for regulating the power captured, the invention allows, in a preferred embodiment, the use of a three-phase asynchronous motor as a generator. The power of the wind turbine according to the invention is preferably regulated so as to make the best use of the electric generator 52, in particular so as not to exceed the maximum permissible power.

The rotor 51 is in the preferred embodiment of Figures 1 to 5, consisting of a circular rim 53 connected to a hub 54 by spokes 56. The hub 54 is rotatably mounted on the transverse frame 13, with an axis of rotation parallel to the plane of inclination for any inclination of the support arm. Sails 57 are stretched between spokes 56 and anchors 58 to the rim. Said anchors are connected to the rim so as to stretch the sail. Preferably each web 57 has a substantially triangular shape between the anchor 58 defining a vertex, and the radius 56 defining the opposite side of the triangle. The sail can be in different materials such as for example textiles or synthetic materials.

In a still preferred embodiment, the sail is folded on itself around a radius 56, two opposite anchors 58 of the sail being contiguous, the radius 56 being in the fold. So that the radius can be of simple geometry, in particular cylindrical, and does not require fasteners intended to maintain the sail relative to the radius. Alternatively or complementary the sail may comprise a longitudinal seam along the radius so as to achieve a sheath. Preferably each rotor 51 is connected to a respective electric generator 52 via a belt 59. The belt is preferably stretched between firstly the rim 53 and secondly a generator pulley 61. preferential embodiment, the outer surface of the rim has a peripheral groove for guiding the belt on the rim. The rim is chosen with a radius greater than the radius of the generator pulley 61 so as to achieve a multiplier between the rotor and the generator.

In the particularly preferred embodiment of Figures 1 to 5, the wind generator 2 comprises two disjoint rotors 51, symmetrical with respect to the support arm 2 and the inclination plane. Each of the rotors is associated with a belt 59, a generator pulley 61 and a generator 52 distinct, placed symmetrically with respect to the support arm 2 and the inclination plane. The generators are preferably placed near the support arm 2.

When the wind turbine comprises several rotors 51 and / or several generatrices 52, these are preferably provided to minimize the gyroscopic effect generated by the displacement of the wind group. In the particularly preferred embodiment of Figures 1 to 5, the two rotors and two generators preferably rotate in opposite directions. In a preferred embodiment, the wind generator comprises at least one braking device 62 acting on the rotors to slow down and / or immobilize the rotors. The braking unit preferably comprises a braking shoe 63 pivoting at least temporarily around a shoe axis 64 as illustrated in the example of FIG. 5, so that the aerodynamic forces acting on the shoe tend to rotate the pad towards the rotor. The braking force exerted increases as the aerodynamic forces increase. Preferably each rotor 51 comprises a braking pad 63 adapted to press on the rim 53 to exert friction braking. In a preferred embodiment, the braking pad 63 is selectively kept at a distance from the rim 53, preferably by an electromagnetic striker 66, so as not to brake the rotor in normal use. The braking pad is capable of being selectively released to brake the rotor, particularly in the case of strong winds likely to degrade the wind turbine, in anticipation of such winds, or to allow the rotor to be immobilized during maintenance operations. Preferably the electromagnetic strike maintains the shoe in a direction substantially profiled relative to the wind so as to reduce the wind load of the pad and / or not disturb the wind in the rotor. In addition to or as an alternative to the electromagnetic strike 66, the braking device 62 may comprise at least one return spring for bringing the braking shoe 63 closer to or away from the rotor 51. Of course, the invention is not limited to the invention. example described, and arrangements can be made to this example. Naturally, the invention is not limited to the example described, and adjustments can be made to this example. The inclination axis 6 of the support arm and the hinge pin 36 of the leg may be merged.

The turret 39 can be fixed on various supports integral with the ground such as foundations, a pylon, or the support integral with the ground can be replaced by a floating support. It may be provided to supplement or replace the generator group at the top of the carrier arm by various instruments such as meteorological instruments.

Claims (24)

CLAIMS1- Wind turbine comprising: - a support arm (2) having an articulated portion (4) which is articulated relative to the ground (3) with freedom of rotation in inclination and in azimuth, - at least one wind group (1) connected to a mobile part (7) of the support arm, located at a distance from the articulated part, so that the aerodynamic forces experienced by the wind group tend to pivot the support arm downwards in a plane of inclination parallel to the wind direction and decrease the altitude of the wind group; a force generator (9), in particular a counterweight, for producing a return force; - balancing means (8) for converting the return force into a moment of return of the carrier arm upwards, the balancing means comprising adjustment means (22) responsive to the inclination of the carrier arm to varying the moment of return in the opposite direction of the altitude of the wind turbine group, a lever (16) being at least indirectly in relation of transmission of restoring force with the carrying arm, characterized in that the balancing means form with the support arm a structure with adjustable geometry and that the adjustment means control an adjustment of said geometry. 2- wind turbine according to claim 1, characterized in that the lever (16) balancing means (8) has a hinge means conferring an adjustable inclination and means (19) for connection to the force generator ( 9), and in that the adjusting means (22) move the connecting means relative to the articulation means. 3- wind turbine according to claim 2, characterized in that the means (19) for connection comprises a carriage (23) sliding along the lever (16), the force generator (9) being connected to said carriage. 4-wind turbine according to claim 1, characterized in that the balancing means (8) comprise: - the lever (16) having a hinge means conferring an adjustable inclination and a retaining means (18), the generator stress (9) acting on the lever; a return force transmitting member (11) connecting at least indirectly the retaining means (18) and the carrying arm (2), and the adjusting means comprise moving means for moving the retaining means on the the sink. 5-wind turbine according to claim 1, characterized in that the balancing means (8) comprise the lever (16) rotatable by a hinge means and carrying a connection means (19) to the force generator (9) and retaining means (18); - a return force transmitting member (11) at least indirectly connecting the carrying arm (2) and the retaining means, and in that the adjusting means comprises means for displacement to move at least one of the hinge, connecting and retaining means relative to the other two. 6. Wind turbine according to claim 5, characterized in that the displacement means move the connecting means (19) and the retaining means (18) in opposite directions of the other along the lever (16). 7- Wind turbine according to claim 6, characterized in that the displacement means comprise a coupling cable (26) forming a loop stretched between two diverting pulleys (27, 28) carried by the lever (16), the connection means (19) and the retaining means (18) being each connected to a respective one of two opposite strands (29, 31) of said loop. 8- Wind turbine according to one of claims 4 to 7, characterized in that the return force transmission member is a cable (11) whose length is adjustable by a winch (42) for bringing the arm carrier (2) lying down for maintenance or in case of storm. 9- wind turbine according to claim 8, characterized in that the cable (11) extends above a stop (44) and bears against this stop when the support arm (2) is in the supine position. 10- Wind turbine according to claim 8 or 9, characterized in that the winch (42) is placed close to the ground (3) and the cable (11) extends from the winch to the support arm (2) through a pulley of return (41) belonging to the retaining means. 11- Wind turbine according to one of claims 4 to 10, characterized in that the adjusting means (22) comprise a leg (34) articulated at least indirectly: - on the one hand relatively to the ground (3) away from the lever (3); - on the other hand by means of restraint. 12- Wind turbine according to claims 10 and 11, characterized in that the winch is close to an articulation between the leg and the ground (3), and / or the winch is fixed on the leg. 13- Wind turbine according to one of claims 4 to 12, characterized in that the retaining means comprises a retaining carriage (11) slidably mounted along the lever (3) for moving the retaining means on the lever. 20 14- Wind turbine according to one of claims 2 to 13, characterized in that the lever is orientable about a vertical axis to be substantially in the same vertical plane as the carrier arm (1). 15- wind turbine according to one of claims 2 to 14, characterized in that the means of articulation of the lever (3) is placed higher than the articulated part of the support arm (1) in particular substantially above the articulated part. 16- Wind turbine according to one of claims 1 to 15, characterized in that it comprises a turret (39) which is rotatable about an axis vertical to the ground (3), and to which the support arm ( 2) is articulated about a horizontal axis of inclination (6). 17- Wind turbine according to one of claims 2 to 15, characterized in that it comprises a turret (39) which is rotatable about a vertical axis with respect to the ground (3), and with respect to which the support arm (2) and the lever (34) are articulated in inclination. 18- wind turbine according to one of claims 1 to 17, characterized in that it comprises as an electric generator (52) an asynchronous three-phase motor. 19- Wind turbine according to one of claims 1 to 17, characterized in that the wind turbine group (1) comprises at least one rotor (51) consisting of a circular rim (53) connected to a hub (54) by radii (56), webs (57) being stretched between the spokes and anchors (58) to the rim. 20- Wind turbine according to claim 19, characterized in that an electric generator (52) is driven by the rotor (51) by means of at least one belt (59) wound at least partially around the rim (53). 21- wind turbine according to one of claims 1 to 20, characterized in that the wind turbine group (1) comprises at least one braking device (31). 20 22- wind turbine according to claim 21, characterized in that the braking device (62) comprises a braking pad (63), pivoting at least temporarily around a pad axis (64) so that the aerodynamic forces s' exerting on the shoe tend to pivot the shoe to a braking activation position. 23- Wind turbine according to one of claims 1 to 22, characterized in that the wind generator (1) is associated with the support arm (2) by a pivot connection, or temporary pivot having a pivot axis oriented according to the normal to the plane tilting rotation of the carrier arm. 24- wind turbine according to one of claims 1 to 23, characterized in that the wind turbine unit is connected to the support arm (2) so that in service of the rotors of the wind group rotate in a substantially vertical plane when the altitude the wind group is maximum, and in a plane that tilts at the same time as the carrier arm when the altitude of the wind group decreases.