"WIND ELECTRIC GENERATOR"

[0001] . The present invention relates to a device for the generation of electric energy from renewable sources and, particularly, a wind electric generator.

[0002] . The generation of electric energy from renewable sources has become a more and more felt need worldwide in the last years. The risk that, in a not very far future, the extraction of petroleum may stop or slow down due to the exhaustion of the oil deposits, or also to other reasons of political or economical nature, has given a push to the search for new sources of energy. Then, reasons of ecological nature have concentrated many efforts on the development of low environmental impact systems, especially those systems not involving the discharge of harmful substances into the air or water. Among these systems, the solar power generators, the utilization of geothermal energy, and the wind electric generators can be mentioned. [0003] . Wind energy is already broadly exploited in the USA, Europe, and in other industrialized countries, above all in those countries that are exposed to considerable ventilation. The need to spread its use potentially to the whole territory, and to each weather condition, has provided the drive for the development of highly efficient devices, that is, such as to advantageously operate also in the presence of a low ventilation. [0004] . The wind electric generators are generally composed of a tower which is even more than 100 meters high, so as to better intercept the wind, on top of which the electric generator is located. The electric generator is composed of an alternator and a motor reducer, the shaft of which is made to rotate, through suitable gears, by a large-sized blade which intercepts the wind energy. [0005] . However, the known wind plants have several drawbacks, which limit the diffusion thereof. First of all, the difficulties with the installation, requiring the transport and positioning of the large-sized and heavy elements constituting the plant, make the installation at the highest, thus hardly accessible, points substantially impracticable. Anyway, the installation and maintenance cost is extremely high, since it is necessary to use large-sized fixtures, particularly cranes. [0006] . Second, the visual impact of the known plants is such as to discourage the installation within protected landscape environments. In fact, it is impossible to camouflage the above-described plants in a natural environment. [0007] . Another problem related to the known wind generators is the functioning efficiency. While in some cases the ventilation is so weak, or even absent, to make the plant productivity to collapse, in the moments of strong ventilation, instead, an energy overproduction can be obtained, leading to storage and distribution, as well as structural and mechanical safety problems. In substance, therefore, the wind plants are affected by a functioning unevenness problem.

[0008] . Therefore, the object of the present invention is to provide a wind electric generator which addresses one or more of the problems set forth above. [0009] . Such object is achieved by a wind electric generator as outlined in the annexed claims, the definitions of which form an integral part of the present description.

[0010] . Further characteristics and the advantages of the present invention will be more clearly understood from the following description of an embodiment, given by way of non-limitative example only, in which: - Fig. 1 represents a sectional side view of a wind electric generator according to the invention;

- Fig. 2 represents a top schematic view of the turbine of the wind electric generator of Fig. 1;

- Fig. 3 represents a sectional side view of a detail of the wind electric generator of Fig. l; - Fig. 4 represents a schematic view of a detail of the wind plant of Fig. 1;

- Fig. 5 represents a top view of a second embodiment of the turbine of the wind electric generator of the invention;

Fig. 6 represents a side view of the turbine blade of Fig. 5 ;

- Fig. 7 represents a view of a detail of the blade of Fig. 6; - Fig. 8 represents a view along the direction A of the detail of Fig. 7;

- Fig. 9 represents a side view of a different embodiment of the wind electric generator of Fig. 1.

[0011] . With reference to the Figures, the wind electric generator of the invention, generally indicated with the number 1, comprises a tower 2, on top of which wind collection means 3 are arranged.

[0012] . The tower 2 comprises a plurality of telescopic segments 4', 4", 4'''. In the drawing, the tower 2 has three telescopic segments, but it shall be apparent that it will be able to comprise only two of them or, vice versa, four or more, according to the needs.

[0013]. The first telescopic segment 4' starting from the bottom comprises a base 5 for the anchoring to the ground, according to conventional methods used in the field.

[0014]. Instead, the top telescopic segment 4'" supports said wind collection means 3, as it will be described herein below. [0015]. The telescopic segments 4', 4", 4''' can have a tubular shape, as shown in the drawing, or a pylon shape, essentially similar to that of a crane. In the latter case, the whole structure will have a lesser weight and a more aerial visual impact, without for this renouncing to robustness and stability.

[0016] . The tower 2 will be able to be made of cement, steel, or other metal alloys, and it will be able to be painted in a colour appropriate to the surrounding environment . [0017]. The telescopic segments 4', 4", 4''' are hollow and are slidable into one another along suitable guides

(not shown) . A rope or hydraulic system of a conventional type, such as that employed in the construction crane, will be further provided for in order to obtain the telescopic lifting or lowering of the tower 2 between a retracted position of the telescopic segments 4', 4", 4 ' ' ' , corresponding to the tower 2 minimum height, and an extended position of said telescopic segments 4', 4", 4 ' ' ' , corresponding to the tower 2 maximum height . It will be also possible to arrange the telescopic segments 4', 4", "4''' in an intermediate position between said extreme positions, thanks to suitable fixing means, such as pawls to be inserted through suitable through holes drilled in alignment through the walls of the telescopic segments, ratchet lock systems, hydraulic or pneumatic lock systems, or other systems known to those skilled in the art.

[0018] . The wind collection means 3 arranged on top of the upper telescopic segment 4''' consist of a case 6 in which a vertical axis turbine 7 is housed.

[0019] . The turbine 7 comprises a stator 8 and a rotor 9. The stator 8, constituting the case 6 side walls, comprises a plurality of orientable vanes 10, so as to better exploit the wind impact force on the rotor 9. As shown by way of example for a single vane 10 in Fig. 2, the orientation of all the vanes 10 will be able to be implemented thanks to a rotation thereof, shown by the arrows, around a vertical axis 11 which is pivoted on the case 6 structure. [0020] . In an embodiment, the case 6 side surface, externally relative to the vanes 10, comprises a loose mesh netting (not shown) , as a bird control netting.

[0021] . The case 6 superiorly comprises an opening 30, acting as a vent outlet for the air intercepted by the turbine 7. [0022] . In an embodiment, the circular crown 31 constituting the case 6 roof comprises solar panels for the production of further electric energy, which will be able to be used, for example, for the operation of all the service uses of the wind power station (lighting, control and check units, electric actuators, electrovalves, etc . ) .

[0023] . The rotor 9 is idle mounted on the telescopic segment 4''', and comprises a plurality of blades 12. The blades 12, in the embodiment shown in Fig. 2, have a concave profile, so as to better intercept the push generated by the wind oncoming through the stator 8.

[0024] . In an embodiment, the blades 12 are made of a light material, such as aluminium alloy or wood coated with glass fibre or carbon fibre, or they are entirely made of carbon fibre, so as to give them the required strength and elasticity.

[0025]. The total area of the rotor 9 blades 12, that is the total area of wind impact, will be able to range between 500 sqm and 2500 sqm, or between 1000 and 2000 sqm, according to the power which is desired to be installed.

[0026] . The wind collection means 3 are operatively connected, through a transmission and transformation system of . the wind energy, to electric energy generator v.

8

means 22 .

[0027] . In an embodiment of the invention shown in the

Figures, the wind energy transmission and transformation system comprises motion transmission and transformation means 14, which are operatively connected to said wind collection means 3 and which transmit the motion from the turbine 7 to a plurality of hydraulic pumping means 15.

[0028] . In the example shown in the Figures, such motion transmission and transformation means 14 comprise a toothed wheel 13, mounted integral to the rotor 9 shaft, along the perimeter of which driven toothed wheels 16 mesh. In other embodiments, different motion transmission and transformation systems, selected from the conventional ones which are known to those skilled in the art, will be able to be used.

[0029] . Each of the driven toothed wheels 16 is integral to a shaft 17 which, in turn, transfers the motion to the rotor of respective hydraulic pumping means 15. The hydraulic pumping means 15 will typically be two or more; for example, eight hydraulic pumping means 15 will be arranged at regular intervals around the toothed wheel 13.

[0030] . The hydraulic pumping means 15 are typically high pressure hydraulic pumps. [0031] . Each of the hydraulic pumping means 15 is operatively connected to a closed hydraulic circuit which comprises a delivery tube 18 and a return tube 19. Such tubes 18, 19 are flexible, and have a length at least corresponding to the tower 2 maximum height, so as to accommodate the different height adjustments of the same tower 2.

[0032] . The closed hydraulic circuit further comprises motorization hydraulic means 20, to which the tubes 18, 19 are operatively connected. The motorization hydraulic means 20, which may be, typically, a hydraulic motor or a hydraulic motor reducer, are associated to respective electric energy generator means 22, typically alternators, through transmission means 21. Typically, such transmission means 21 will be implemented by means of a driving shaft. In this manner, the high pressure fluid pumped by the hydraulic pumping means 15 actuates the motorization hydraulic means 20 which, in turn, convert the kinetic energy into electric energy for the production of alternate current by means of the alternator 22.

[0033] . As stated before, electric energy generator means 22 correspond to each hydraulic pumping means 15. Said means 22 are connected to an electric energy transformation and distribution system of the conventional type (not shown) , which will comprise potential booster converters, a network of power lines and transformers adapted to reduce the voltage according to the needs of the various users.

[0034] . In an embodiment of the invention, the motion transmission and transformation means 14, or the motorization hydraulic means 20, comprise transmission engaging/disengaging means (not shown) . Such means will be controlled or they will be automatic, and may comprise, for example, engaging/disengaging mechanic means provided with coupling systems such as, for example, two discs couplable by means of an axial toothing, or a clutch. If said mechanical transmission engaging/disengaging means are a clutch, they will be preferably a dry clutch, an oil-immersed clutch, or a centrifugal clutch.

[0035] . In another embodiment, in place of such transmission engaging/disengaging means, the hydraulic pumping means 15 comprise a secondary by-pass hydraulic circuit and by-pass valving means, adapted to recirculate the fluid within said secondary hydraulic circuit, therefore excluding the above-described closed hydraulic circuit comprising said tubes 18, 19. Such by-pass valving means comprise, for example, a three-way electrovalve, of the type adapted to high pressures (about 200 bars) . Therefore, in this embodiment, when the secondary by-pass circuit is selected, the hydraulic pumping means 15 rotor will always be operative, but it will run idle and not send the pressurized fluid to the motorization hydraulic means 20 through the delivery tube 18.

[0036] . In this manner, or by operating on said transmission engaging/disengaging means, or having one or more hydraulic pumping means 15 to run idle, it is possible to exclude one or more electric energy generator means 22 from production when the number of rotations of the turbine 7 is below predefined threshold limits. This need can occur when the wind blows with low speed. Vice versa, as the wind speed and, therefore, the available wind energy increases, a number of electric energy generator means 22 will be able to be progressively put to production, exploiting at the best the potentiality of the plant. However, if the wind exceeds a given threshold limit - which may vary according to the power of the installed wind plant - such as, for example, during a gale, the above-described procedure will be able to be reversed, progressively excluding one or more electric energy generator means 22 from production, so as to avoid an overproduction, which is difficult to be used.

[0037] . In a further embodiment, it is possible to reduce the wind impact on the turbine 7 blades 12, and therefore the rotation speed of the same, by reducing the window between the stator 8 vanes 10, by rotation of the vanes 10 around their vertical axis 11. Therefore, in this manner it is possible to avoid an overproduction of electric energy without having to exclude one or more electric energy generator means 22 as described above, or by synergically operating with said procedure of exclusion of the means 22.

[0038] . In an embodiment shown in Fig. 4, the wind electric generator of the invention comprises an automatic system 23 for the distribution of the power to the various electric energy generator means 22.

[0039] . Such automatic system 23 comprises measuring means 24 of the wind speed and, optionally, the wind direction, typically an anemometer or an electronic sensor, connected to a control and check unit 25 which, in turn, is operatively connected, by means of suitable wiring 26, to electric actuators connected to each of the mechanical transmission engaging/disengaging means associated to the motion transmission and transformation means 14 or to the motorization hydraulic means 20 - or, alternatively, to said by-pass valving means of the hydraulic pumping means 15. Furthermore, said control and check unit 25 will be operatively connected to electric actuators (not shown) of the orientable vanes 10 of the stator 8, so as to drive the opening/closure thereof, thereby the orientation thereof.

[0040] . The control and check unit 25 performs the following functions: - reading the wind speed; assigning a first wind speed threshold value different for each transmission engaging/disengaging means to each of said transmission engaging/disengaging means, so as to create a first set of preset incremental threshold values; comparing the read speed value to said first set of preset incremental threshold values; send an on-off control signal to each of said transmission engaging/disengaging means, in which said "on" control corresponds to the engagement of the transmission, and in which each of said control signals is an "off" control if the read wind speed value is lower than the corresponding threshold value, while it is an "on" control if the read wind speed value is higher than the corresponding threshold value.

[0041] . Thus, it is possible to exploit at the best the wind energy, increasing the electric energy production as the wind energy becomes available. [0042] . Alternatively, the control and check unit 25 is capable of: reading the wind speed; assigning a first wind speed threshold value different for each by-pass valving means to each of said by-pass valving means, so as to create a first set of preset incremental threshold values; comparing the read speed value to said first set of preset incremental threshold values; sending an on-off control signal to each of said bypass valving means, in which said ^w on" control corresponds to the delivery of the fluid through the respective delivery tube 18, and said ^u off" control corresponds to the interruption of said delivery, and in which each of said control signals is an "off" control if the read wind speed value is lower than the corresponding threshold value, while it is an "on" control if the read wind speed value is higher than the corresponding threshold value.

[0043] . Furthermore, the control and check unit 25 is capable of: - reading the wind speed;

- assigning a second wind speed threshold value different for each transmission engaging/disengaging means or each by-pass valving means to each of said transmission engaging/disengaging means or said by- pass valving means, so as to create a second set of preset incremental threshold values, in which the lowest threshold value of said second set is higher than the highest threshold value of said first set, and it is higher than or equal to a preset wind speed value;

- comparing the read speed value to said second set of preset incremental threshold values;

- sending an on-off control signal to each of said transmission engaging/disengaging means or each of said by-pass valving means, in which said "on" control corresponds to the engaging of the transmission or the delivery of the fluid through the respective delivery tube 18, respectively, and in which each of said control signals is an "on" control if the read wind speed value is lower than the corresponding threshold value of said second set, while it is an "off" control if the read wind speed value is higher than the corresponding threshold value of said second set. [0044] . In an embodiment, the control and check unit 25 performs the following further functions:

- Reading the speed and direction of the wind;

- Comparing the read speed to a preset threshold value; - Sending a control signal to the actuator of the orientable vanes 10 of said stator 8, so as to orientate said vanes 10 as a function of said read wind direction and/or as a function of said read wind speed, in which the window between said vanes 10 is decreased if said read wind speed is above said preset threshold value.

[0045] . Therefore, as described above, the wind electric generator of the invention will be able to exploit at the best the potentialities thereof according to the wind speed: in fact, up to a given speed, the energy production will be progressively increased as a function of the increasing wind energy available; whereas, if the wind speed rises beyond a given preset threshold, one or more electric energy generator means 22 will be able to be automatically disengaged, thus avoiding an electric energy overproduction.

[0046] . The wind electric generator of the invention may be completed by an access system to the tower 2 top and a platform extending around the turbine 7 case 6. This platform can be used both to make the maintenance of the turbine 7 and the hydraulic pumping means 15 easier, and as a sighting post, for example, for the civil defence or the forest ranger. To this aim, remote smoke detectors may be installed on the platform, for the monitoring of possible wildfires. Such smoke detectors will be generally connected to a remote alarm system. [0047] . In a different embodiment shown in the Figures 5-8, the turbine 107 comprises a stator 108 and a rotor 109 having a plurality of blades 140 composed of a frame 141, typically made of metal tubing, on which a network 142 is laid, also typically a metal network. A face of such network 142, intended to intercept the wind, is coated with a sheet of a rigid material, such as glass fibre, carbon fibre, or rigid plastic material. [0048]. As shown in the Figures 7 and 8, a trolley 143 is arranged at the free end of the frame 141, along the lower edge. The trolley 143 comprises one or more (in the drawing, three) rollers or rolls 144, intended to slide along a truck 145 running along the turbine 107 outer perimeter, so as to constitute a support for the blades 140, particularly when the dimensions of the latter are very high. The rollers or rolls 144 are made of a low friction coefficient material such as, for example, Teflon. [0049] . In a further embodiment, shown in Fig. 9, the wind electric generator 1 comprises, besides the central tower 2, one or more additional towers or columns 150, arranged along the case 6 perimeter. Such towers or columns 150 are also telescopic, and can be lifted, lowered, and secured in a given position by means of systems that are similar to those described above for the telescopic tower 2. In the example of Fig. 9, the structure of the additional towers or columns 150 is a pylon, but it also may be tubular or of another shape suitable to the purpose. The towers or columns 150 may be made of steel, cement, or other material with high mechanical strength and high load-carrying capacity.

[0050] . The base of the additional towers or columns

150 is anchored to the ground, similarly to the tower 2, while the upper end is connected to the case 6 lower surface through an articulated joint 151, the object of which is to decrease the rigidity of the installation and to avoid breaking loads on the materials.

[0051] . The embodiment shown in Fig. 9 is particularly suitable in the case where the turbine has large dimensions (for example, 80 meters diameter) to increase the plant stability and to allow the installation thereof also on uneven grounds.

[0052]. In Fig. 9, the wind electric generator 1 comprises a turbine 107 as described in the Figures 5-8, but it shall be apparent that it will also be able to mount the turbine 7 of Fig. 2.

[0053] . The advantages of the invention shall be apparent from what has been described above. [0054] . First, the telescopic structure of the tower 2 allows simplifying the transport and installation operations, requiring a crane with a lesser height and power than that required to erect the conventional wind plants. Furthermore, it is possible to adjust the tower 2 to the height suitable for an optimal interception of the wind, which is not necessarily the maximum height. This also allows limiting the visual impact of the installation.

[0055] . The use of a vertical axis turbine in place of the conventional horizontal axis blades drastically reduces the visual impact of the plant.

[0056] . Arranging the alternators 22 at the tower 2 base instead of on top - as occurs, on the contrary, in the conventional plants - allows reducing the weight of the plant portion arranged on the top of the tower 2, which basically translates in a saving of the considerable installation costs. Furthermore, the presence of these equipments at the base reduces the intervention and maintenance times and costs. [0057] . The provision of a plurality of hydraulic pumping means 15 which are disengageable or engageable according to the wind speed allows modulating the plant operativeness as a function of the weather conditions, in order to keep the productiveness as constant as possible, which problem is intrinsic to the conventional plants. Furthermore, the risk of a complete halt of the plant due to a failure is substantially reduced, since at least one alternator will always be operative.

[0058] . It shall be apparent that those of ordinary skill in the art will be able to make a number of variations to the invention, without however departing from the protection scope defined by the claims which are herein annexed.

[0059] . For example, it will be possible to replace the turbine 7 with a conventional horizontal axis blade, while maintaining the other characteristics of the above- described plant, particularly the telescopic structure of the tower 2.

[0060] . Alternatively, the turbine 7 will be able to have a different structure from that shown in the

Figures. For example, a Savonius wind turbine will be able to be used, or another known type which is capable of exploiting at the best the impact of the wind.

[0061] . Furthermore, the energy transmission from the turbine to the alternator through a closed hydraulic circuit will be able to be replaced by a conventional mechanical transmission.