CA2019252A1 - Method for regulating an air machine for the conversion of wind energy to useful energy, and machine for carrying out said method - Google Patents
Method for regulating an air machine for the conversion of wind energy to useful energy, and machine for carrying out said methodInfo
- Publication number
- CA2019252A1 CA2019252A1 CA002019252A CA2019252A CA2019252A1 CA 2019252 A1 CA2019252 A1 CA 2019252A1 CA 002019252 A CA002019252 A CA 002019252A CA 2019252 A CA2019252 A CA 2019252A CA 2019252 A1 CA2019252 A1 CA 2019252A1
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- CA
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- Prior art keywords
- recuperator
- machine
- axis
- accordance
- wind
- Prior art date
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- Abandoned
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/70—Wind energy
- Y02E10/72—Wind turbines with rotation axis in wind direction
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- Wind Motors (AREA)
Abstract
A B S T R A C T
Company known as :
TOUTENKAMION and Marc GIRERD and Eric GIRERD
"Method for regulating an air machine for the conversion of wind energy to useful energy, and machine for carrying out said method".
(Invention by GIRERD Marc and GIRERD Eric) A mast (1) supports a vane-type energy recuperator (4) by means of a frame (2) which is orientable about a vertical axis (3). An energy conversion device (9) is connected to the recuperator (4) in order to be driven in rotation by the recuperator (4). The frame (2) is responsive to the aerodynamic force exerted on the recuperator (4) in order to self-position the recuperator (4) with respect to the mast (1) and to the ground in the direction of optimization of the power collected by the machine.
The frame (2) comprises a turret (31) pivoted to the mast (1) about the axis (33 and a structure pivoted to the turret (31) about a horizontal axis (42) of tilting motion. A balance weight (14) maintains the recuperator (4) in the top position when there is no wind. The aerodynamic drag of the recuperator acts in the opposite direction. In consequence, in the event of a high wind, the recuperator moves down towards the ground where the wind is of lower strength. One position of equilibrium corresponds to each wind intensity.
To be used for self-regulating the machine and protecting it against climatic hazards.
See FIG. 7.
Company known as :
TOUTENKAMION and Marc GIRERD and Eric GIRERD
"Method for regulating an air machine for the conversion of wind energy to useful energy, and machine for carrying out said method".
(Invention by GIRERD Marc and GIRERD Eric) A mast (1) supports a vane-type energy recuperator (4) by means of a frame (2) which is orientable about a vertical axis (3). An energy conversion device (9) is connected to the recuperator (4) in order to be driven in rotation by the recuperator (4). The frame (2) is responsive to the aerodynamic force exerted on the recuperator (4) in order to self-position the recuperator (4) with respect to the mast (1) and to the ground in the direction of optimization of the power collected by the machine.
The frame (2) comprises a turret (31) pivoted to the mast (1) about the axis (33 and a structure pivoted to the turret (31) about a horizontal axis (42) of tilting motion. A balance weight (14) maintains the recuperator (4) in the top position when there is no wind. The aerodynamic drag of the recuperator acts in the opposite direction. In consequence, in the event of a high wind, the recuperator moves down towards the ground where the wind is of lower strength. One position of equilibrium corresponds to each wind intensity.
To be used for self-regulating the machine and protecting it against climatic hazards.
See FIG. 7.
Description
'- ?)~g2~2 "Method for regulating an air machine for the conversion of wind energy to useful energy, and machine for carrying out said method"
The present invention relates to a method for regulating an air machine for the conversion of wind energy to useful energy.
The present invention also relates to a machine for the application of said method.
The FR - A - 2 568 948 discloses a wind engine comprising a mast and a tilting structure which is pivoted at the top end of this latter about a horizontal axis, this tilting structure being in turn adapted to carry at its free end an energy recuperator comprising a vane-type rotor. Under service conditions a spring-loaded system maintains the tilting structure in an angular position of maximum elevation of the recuperator. In the event of a sudden gust of wind, the tilting structure is inclined momentarily, subject to increased tension of the spring. Furthermore, it is possible for maintenance of the recuperator to lower this latter to the ground by pivotal displacement of the tilting structure about the horizontal axis. A system of this type is not conducive to regular production of energy. The machine usually operates below its rated capacity when the wind is light. In the event of a gust of wind, the damping movements permitted by the spring result in fluctuations in production.
The present invention relates to a method for regulating an air machine for the conversion of wind energy to useful energy.
The present invention also relates to a machine for the application of said method.
The FR - A - 2 568 948 discloses a wind engine comprising a mast and a tilting structure which is pivoted at the top end of this latter about a horizontal axis, this tilting structure being in turn adapted to carry at its free end an energy recuperator comprising a vane-type rotor. Under service conditions a spring-loaded system maintains the tilting structure in an angular position of maximum elevation of the recuperator. In the event of a sudden gust of wind, the tilting structure is inclined momentarily, subject to increased tension of the spring. Furthermore, it is possible for maintenance of the recuperator to lower this latter to the ground by pivotal displacement of the tilting structure about the horizontal axis. A system of this type is not conducive to regular production of energy. The machine usually operates below its rated capacity when the wind is light. In the event of a gust of wind, the damping movements permitted by the spring result in fluctuations in production.
2~ The US - A - 4 142 830, EP - A - 0033258 and DE - A - 28 10 239 disclose machines in which the recuperator is oriented about a horizontal axis in order to be placed obliquely in the airstream and thus collects with lower efficiency an airstream of smaller cross-sectional area when the wind becomes strong. These machines are very badly protected against climatic hazards.
2 ~
The object of the invention is to propose an air machine of the type indicated at the outset, which permits high energy production over a wide range of wind forces while being well protected against climatic hazards.
According to the first aspect of the invention, the method for regulating an air machine for the conversion of wind energy to useful energy, of the type comprising a rotary energy recuperator which is capable of moving to different heights, is characterized in that the recuperator is positioned in a substantially stable manner at a height with respect to the ground which is a decreasing function of the force of the wind.
According to the second aspect of the invention, the air machine for the conversion of wind energy to useful energy, comprising a mast, a rotary energy recuperator, means for height displacement of the recuperator with respect to the mast under the action of the aerodynamic force exerted on the recuperator and in opposition to restoring means, and an energy conversion device connected to the recuperator in order to be driven in rotation by the recuperator, is characterized in that the height displacement means are designed to position the recuperator in a substantially stable manner at a height above ground which is a decreasing function of the force of the wind.
The invention is based on the observation that the force of the wind is lower as the wind is closer to the ground. The recuperator of the machine in accordance with the invention comes into position and operates closer to the ground as the wind is stronger.
The machine can be dimensioned so as to deliver its rated power with a relatively light wind which will be collected at a substantial height above ground and so as to deliver substantially the same power in a high wind which is collected much nearer the ground.
Thus the collected power is often close in value to the rated power and the second result achieved is that the recuperator is sheltered or in other words close to the ground in the event of a high wind.
The method in accordance with the invention is such that the height of positioning of the recuperator is a decreasin~ function of the force of the windO This does not rule out the possibility that the height of positioning of the recuperator can be a function of - other variables. In particular, for a given force of wind, the height of the recuperator may vary as a function of the power required of the machine by users of the energy produced.
Preferably, when the height displacement means comprise a tilting structure which carries the recuperator at a distance from a substantially horizontal axis of tilting motion on which said tilting structure is articulated with resPect to the maqt, the restoring means are provided by an arrangement whereby a vertical ideal plane containing the axis of tilting motion extends between the recuperator and the center of gravity of the moving system (that is to say, for example, the assembly comprising the tilting structure, the recuperator and a balance weight) which is capable of moving about the axis of tilting motion.
The result thereby achieved is to minimize the bending moments sustained by the mast and therefore to minimize the cost of the mast and the cost of its installation. On the contrary, in FR - A - 2 568 948, the spring which partially locks the tilting-motion articulation increases the bending moment sustained by the mast.
In order to limit the upward travel of the recuperator, provision is preferably made for bearing `- 201~2~
means which rest on the ground when the recuperator is in the light-wind position.
In accordance with patent FR-A- 2 569 948, the bearing means rest on the mast and further increase the bending moment sustained by the mast.
It is also preferred that the machine comprises flexible supporting means for suspension of the recuperator. By virtue of these flexible means, the vibrations resulting from operation of the recuperator are decoupled from the remainder of the structure, thus avoiding the risk that these vibrations may produce dangerous resonances within the frame and the mast.
Further particular features and advantages of the invention will be brought out by the description given hereinafter.
In the accompanying drawings which are given as non-limitative exampleS:
- FIG. 1 is a view in perspective of a machine in accordance with the invention ;
- FIG. 2 is a partial explanatory view in elevation of the machine of FIG. 1 ;
- FIG. 3 is a schematic top view of the machine of FIGS. 1 and 2 ;
- FIG. 4 is a view which is similar to FIG. 3 but relates to a second embodiment ;
- FIG. 5 is a view in side elevation of a water tower equipped with a wind engine in accordance with a third embodiment of the invention ;
- FIG. 6 is a top view of the water tower of FIG. 5 ;
- FIG. 7 is a view in perspective showing a fourth embodiment of the machine in accordance with the invention ;
- FIG. 8 is a view in elevation of the machine of FIG. 7, the recuperator being in the top posi-tion ;
` ` ~ 2~9~2 - FIG. 9 is a view to a larger scale showing a portion of FIG. 8, in the event of wind ;
- FIG. 10 is a schematic top view of a fifth embodiment of the invention ;
- FIG. 11 is a view in elevation of the fifth embodiment of the invention ;
- FIG. 12 is a detail of FIG. 11, in the event of wind ;
- FIG. 13 is a schematic view in elevation showing the air machine of FIG. 11, in the presence of a violent wind ; and - FIGS. 14 and 15 are views which are similar to FIGS. 11 and 13 ~ut relate to a sixth embodiment.
In the example shown in FIG. 1, the wind engine comprises a mast 1 anchored to the ground so as to extend vertically upwards from the ground, and a frame 2 which is mounted at the top of the mast 1 so as to be orientable with respect to the mast 1 about a vertical central axis 3 of the mast 1.
The orientable frame 2 carries an energy recuperator 4 comprising two vane-type rotors 60 The central shafts of said rotors are freely mounted for rotation about parallel axes on a mounting support 7.
A peripheral ring 8 of each rotor 6 forms an inertia fly-wheel contributing to regulation of the machine and drives a respective asynchronous machine 9 by meshing or by friction so as to convert the wind energy collected by the machine to electric current.
The asynchronous machines 9 are capable of rotating freely with respect to each other.
The recuperator 4 is connected to the mast 1 in such a manner as to ensure that the aerodynamic forces exerted on the recuperator 4 and in particular on its rotors 6 under the action of wind, the direction of which is represented by the arrow V, result in a 2 ~ 2 variation in the geometry of the machine so that the recuperator is always located in an optimum position with respect to the wind, taking into account the maximum permissible power of the machine, the maximum speed of rotation of t~le rotors, and the required power.
To this end, the recuperator 4 is suspended from the orientable frame 2 by flexible means 11 which are passed over guide pulleys 12 and 13 rotatably carried by the frame 2. At their ends remote from the mounting support 7, the flexible means 11 are attached to a balance weight 14. In the example, the flexible means ll consist of two cables 16 which extend parallel to each other in order to maintain the axes of the two rotors 6 in the same horizontal plane and to maintain them substantially parallel to, and equidistant fro~ a vertical plane P(FIG. 3) which contains the axis 3. It is readily apparent that, since these cables are flexible, positioning of the recuperator 4 is not strictly accura~e. However, said positioning is sufficient in practice since the resultant of the aerodynamic forces exerted on the recuperator does not haveany large component which would be capable of acting between the recuperator and the frame 2 so as to destabilize the recuperator with respect to the frame. On the other hand, the cables 16 are so arranged as to ensure that the only restoring force which acts in opposition to a pendular motion of the recuperator 4 about an axis perpendicular to the plane P is the force which results from the weight of the recuperator 4 and from the energy conversion means 9 which are coupled to this latter.
The mass of this assembly is smaller than the mass of the balance weight 14. In consequence, when no other forces are present and in particular when there is no wind, the recuperator 4 assumes the top position ` -` 2~92~2 - --7~
close to the frame 2 whilst the balance weight 14 is close to the ground.
By contrast, as shown in FIG. 2, when an aerodynamic force F2 is exerted on the recuperator 4, said force which is directed substantially horizontally, is added vectorially to the weight P of the assembly consisting of recuperator 4 and generator 9 in order to give the cables 16 a tension T which is higher at absolute value than the weight P. In view of the fact that the aerodynamic force which may be exerted on the recuperator increases with the height above ground ~FIG. 2 shows the force Fl in the vicinity of the : ground, the force F2 at a mean height above ground and the force F3 at a maximum height of the recuperator), the recuperator 4 stabilizes at a height at which the tension T of the cables 16 at the end nearest the recuperator is equal to the weight of the balance weight 14.
Moreover, as shown in FIG. 2, the angle of slope of the cable 16 above the recuperator 4 departs from the vertical to a greater extent as the aerodynamic force is larger. Thus, in the event of a sudden gust of wind of gale force, the recuperator dodges the gust of wind in two ways, on the one hand by moving away from the mast 1 in the direction of the wind and on the other hand by moving closer to the ground until the tension T again becomes equal to the weight of the balance weight 14.
If the power required by users and delivered by the generators 9 is relatively low, the adjustment carried out by the aforementioned equilibrium between the balance weight 14 and the recuperator may correspond to an excessive speed of rotation of the rotors 6.
As shown in FIG. 3, this drawback can be avoided by mounting a frequency meter 18 on one of the 2 ~ 5 ~
three phase leads 17 of the output line of the generators 9. The output of said frequency meter 18 is directed to one o~ the inputs 19 of a comparator 21, the other input 22 of which is connected to a set point. The output 23 of the comparator 21 controls a servomotor 24 which is mounted on the sha~t of the pulleys 12 and, when it is activated, imparts a torque to these pulleys in the direction of downward displacement of the recuperator 4 towards the ground. It may also happen that the speed of rotation of the rotors 6 is insufficient. This may resu]t from an overload produced by the users. It is possible to guard against such a drawback by providing a circuit-breaker which is capable of putting all or part of the installation out of circuit.
The speed of the rotors 6 may also be insufficient by reason of practically total absence of wind. In this case, even if the recuperator 4 is placed at the maximum height above ground, the speed of rotation of the rotors may be insufficient and the power delivered may be relatively low. Within the limits of a self-contained installation (the machine is connected only to a certain number of well-determined utilization points), it is possible to ensure that the circuit-breaker is responsive to the frequency of the current delivered by the generators 9 and not to the intensity of this current.
In the case of a machine connected to a power supply system 26 (FIG. 4), it is proposed in accordance with the invention to mount capacitors 27 between the phase leads 17 (or alternatively between each phase lead 17 and a neutral point). Moreover, each generator 9 is disposed in engagement with the associated rotor 6 by means of a free-wheel device 28 which enables the generator to rotate at a higher speed than -the - 2 1~ 5 2 g associated rotor. Since the generators 9 are ` asynchronous generators, then in the event of insufficient speed imparted by the rotor 6, the generators 9 then operate as motors which rotate on no load since they do not have to drive the associated rotor 6 by virtue of the free wheels 28. This prevents the generators 9 from impairing the current delivered to users by the power supply system 26.
The recuperator 4 is positioned laterally with respect to the axis 3 of pivotal displacement of the frame 2 in such a manner as to ensure that the centroid B (FIG. 4) of application of the resultant of the aerodynamic forces exerted on the recuperator 4, in particular the forces Fa and Fb exerted on the rotors 6, is located at a distance from the axis 3. Thus the recuperator 4 has a permanent tendency to come into position behind the mast 1 with respect to the direction of the wind by rotational displacement of the frame 2 about the axis 3.
More s~i~ ly, when the line of action L of the resultant F does not pass through the axis 3, it exerts about the axis 3 a rotational moment which tends to cause rotation of the frame and consequently of the recuperator 4 about the axis 3. This situation (shown in FIG. 4) is therefore unstable. In the situation shown in chain-dotted lines, this is a stable situation in which the resultant F has a line of action which passes through the axis 3, the direction of the wind V
being naturally parallel to this line of action. By virtue of the symmetry of the recuperator 4 with respect to the plane P, P is accordingly parallel to the direction of the wind.
Since the centroid B is substantially located in the common plane of the rotors 6, the aforementioned distance between the centroid B and the axis 3 is ~ 2~2~2 achieved by giving the arm 2 a signi~icant length in the plane P, in particular by positioning the axis of the pulleys 12 a~ a significant distance from the axis 3 of pivotal displacement. The position of the axis of the pulleys 13 is substantially symmetrical with that of the axis of the pulleys 12 with respect to the axis 3. Thus the vertical forces exerted on the arm 2 on each side of the axis 3 are substantially the same and the arm 2 does not have to resist a tilting couple.
In order to ensure better symmetry of the forces applied on the machine, the two rotors 6 have vanes which are differently oriented so that they rotate in opposite directions together with the generators 9 which are also disposed symmetrically with respect to the plane P. The fact that the aerodynamic forces exerted on the recuperator 4 are perfectly symmetrical on each side of the plane P and are located at a significant distance on each side of the plane P endows the recuperator 4 with high stability despite the fact that it is suspended only from two cables 16.
In the example shown in FIGS. 5 and 6, the mast 1 is a water tower. Only the differences with respect to the previous example will be described. In this example, the generators 9 supply a pump located at the base of the water tower. The connection between the generators 9 and the pump (not shown) located within the water tower is established by means of a flexible electric wire 28 connected electrically via a rotary contact 29 to a connector located within the hollow interior of the pivot 31 which is secured to the mast 1 and on which the orientable frame 2 is pivotally mounted.
In a machine o. small height, the energy conversion means 9 could be a pump connected by flexible pipes and rotary seals within the pivot 31 which would contain two tubes, one for drawing water by suction and 2a~9~
the other for discharging water.
As shown diagrammatically in FIG. 6, the frame 2 can be rig.idly fixed to two deflectors 32 placed between the body of the water tower 1 and the rotors 6, the function of said deflectors being to guide the airstreams 33 towards the rotors 6.
In the case of the application to a water tower, the speed regulation of the machine is not critical if it is certain that ~here is always a possibility of pumping water to the top of the water tower. It is in fact possible to ensure that, a-t the rated speed of the pump, the power consumed by this latter corresponds to the electric power delivered by the generators 9 when the rotor rotates at its rated speed and when the recuperator is in equilibrium with the balance weight 14. Should the wind be too light, it is not a serious matter if the pump output decreases.
In the case of a water tower, the machine in accordance with the invention is therefore, in its basic principles, completely regulated by the means for self-positioning about the axis 3 and by the means for self-positioning in height by equilibrium with the balance weight 14.
The example of FIGS. 7 and 8 will be described only in regard to the differences between this latter and the example of FIG. 1. The orientable frame 2 comprises a turret 31 which covers the mast 1 and a tilting structure 2a, 2b, 2c which is pivoted to the turret 31 about a horizontal axis 42 of tilting motion by means of an articulation 41. The tilting axis 42 intersects the axis 3 of pivotal displacement at the top of the mast l.
The tilting structure comprises a first individual frame 2a and a second individual frame 2b 2~9~
which are pivoted to each other about the tilting axis 42 and which extend respectively on each side of a vertical plane PV containing the tilting axis 42.
Under the action of their own weight and of the weight of the elements which they carry and which will be described hereinafter, the two individual frames 2a and 2b each tend to pivot downwards, that is to say in opposite directions about the tilting axis 42.
In order to guard against this tendency and to couple the two individual frames 2a and 2b in rotation about the tilting axis 42, the tilting structure comprises in addition two traction cables 2c mounted in parallel, each cable being anchored to the end 2d of the frame 2a and to the end 2e of the frame 2b which are remote from the tilting axis 42. The cables 2c extend above the tilting axis 42 perpendicularly to this latter. Thus in regard to the loads to which it is subjected, the assembly constituted by the frames 2a and 2b and the cables 2c behaves as a rigid structure while being constituted by elements of relatively small size which can be readily assembled in situ. The end 2d of the individual frame 2a is constituted by a fastening member from which the recuperator 4 is suspended.
The fastening member 2d comprises, at that end which is directed laterally away from the plane PV, a tube 53 having a so-called suspension axis 70 which is substantially horizontal and parallel to the axis 42.
Connecting means 16 which are closed in loop, such as two straps, chains or belts mounted in parallel connect the tube 53 to the mounting support 7 and, more precisely, surround the tube 53 and the main beam of the mounting support 7. Said main beam is a tube having an axis 71 which is substantially horizontal and parallel to the axes 70 and 42.
Moreover, the loop connection means 16 are `~ 2 ~
prevented from sliding in the circumferential direction with respect to the tube 53 and with respect to the main beam of the mounting support 7. In this example, the tube 53 is capable of rotating about its axis 70 with respect to the fastening member 2d and its angular position is controlled as a function of the inclination of the structure 2a, 2b, 2c about the tilting axis 42 so as to ensure that the axes of the rotors 6 are horizontal irrespective of said inclination. In the event of wind (FIG. 9), the suspension 16 tilts under the action of the horizontal forces F3 which are exerted on the recuperator but maintains the recuperator in the position in which the axes of the rotors are horizontal. The center of gravity of the recuperator 4 is located on the axis 71 of the mounting support 7, with the result that the weight of the recuperator 4 continuously tends to place the axis 71 in the vertical plane containing the axis 70 and does not exert any torque about the axis 71.
A balance weight 14 is connected to the end 2e of the second individual frame 2b by means of an articulation 52 which permits free rotational displacement of the balance weight 14 about a pivotal axis 43 which is parallel to the axis 42 and distant from the plane PV. As shown in FIG. 8, the balance weight 14 is such that the center of gravity G of the moving svstem (comprising the tilting structure 2a, 2b, 2c, the balance weight 14 and the recuperator 4) is located on the same side of the plane PV as the balance weight 14.
Thus, in the absence of forces other than gravity forces on the moving system 2a, 2b, 2c, 4, 14, in particular when there is no wind, the recuperator 4 takes up the so-called "light wind" top position at a height above ground which is distinctly greater than 2~2~2 that of the axis 42 of tilting motion. The tilting structure 2a, 2b, 2c is in that case steeply inclined and the balance weight 14 is close to the ground. In this situation, the center of gravity G of the moving system is located at a greater height above ground than the tilting axis 42.
When wind is blowing, there is exerted on the moving system 2a, 2b, 2c, 4, 14 an aerodynamic force F3 (FIG. 9) which is considered for the sake of simplici-ty as located in the plane of the axes 6a of the rotors 6 of the recuperator 4. In actual fac-t, taking into account the aerodynamic forces exerted on the frames 2a and 2b, said force is located slightly lower than the axes 6a when the tilting structure is in the light-wind position and at a slightly greater height than the axes 6a when the frame 2a makes a larger angle with the plane PV as will be seen hereafter.
The force F3 applies to the tilting structure about the tilting axis 42 a moment which is orien-ted in the direction opposite to the moment applied by the weight P of the moving system at the center of gravity G.
Thus the recuperator 4 is located in the top position until the wind attains the velocity corresponding to the rated power of the machine.
When the wind attains this intensity threshold, the torque exerted by the aerodynamic force about -the tilting axis 42 exceeds the torque exerted in the opposite direction about the same axis by the weight of the moving system 2a, 2b, 2c, 4, 53 and the moving system pivots about the tilting axis 42 in the direction of downward displacement of the recuperator 4 towards the ground, up to a position of equilibrium in which the moment of the aerodynamic force and the moment of the weight of the moving system about the tilting axis 42 are equal and opposite, that is to say when the torque i 2 ~ 2 exerted by the aerodynamic drag has decreased to a sufficient extent to be no longer in excess with respect to the torque exerted by the weight of the moving system.
This new equilibrium can be found by reason of the fact that, when the tilting structure pivots about the axis 42 in the direction of downward displacement of the recuperator towards the ground, the aerodynamic force F3 decreases in order to become a new force F2 of smaller magnitude since the intensity of the wind is an increasing function of the height above ground.
If the torque exerted by the weight were independent of the inclination of the moving system about the tilting axis 42, the new equilibrium would be attained when the torque exerted by the aerodynamic drag of the moving system has also returned to the threshold value above which the moving system leaves the light-wind position. However, since the lever arm length available to the action of aerodynamic drag decreases when the moving system comes closer to the ground, the aerodynamic force to which this threshold value of torque of the aerodynamic force would correspond would be of greater magnitude as the recuperator would be nearer the ground. Under these conditions, the power delivered by the machine would tend to be higher as the recuperator 4 is nearer the ground. These disadvantages are avoided by vixtue of the particular position of the center of gravity G of the moving system 2a, 2b, 2c, 4, 53 which is located at a slightly higher altitude than that of the tilting axis 42 when the tilting structure is in the light-wind position.
Thus, when the tilting structure pivots towards another position about the tilting axis 42, the vertical line Y (FIG. 8J which passes through the center of gravity G comes closer to the axis 42 and the torque 2~2~2 exerted by the weight of the moving system consequently decreases.
In consequence, the aerodynamic torque which is necessary in order to balance the torque due to the weight also decreases. Thus it is possible to ensure that the aerodynamic drag exerted on the recuperator varies little as a function of the inclination of the tilting structure In the example shown in FIGS. 7 to 9, the particular position of the center of gravity G is obtained by giving an upwardly directed concavity to the broken line which passes through the axes 43, 42, 71.
In the embodiment of FIGS. 10 and 11, the balance weight 14 is provided with rolling means 50.
These rolling means can comprise one or a number of wheels such as, for example, two wheels 50a, 50b joined together by means of an axle 50c, the axis of which intersects the axis 3, at least when the tilting structure is in the light-wind position as shown in FIG. 11, in which case the wheels 50a, 50b bear on two rails 58a, 58b of a circular track 80 whose axis coincides with the axis 3 of pivotal displacement, said track being arranged on the ground around the mast 1.
Application of the wheels 50a, 50b on the track 80 defines the light-wind position of the tilting structure.
In this positionr the balance weight 14 does not exert any torque on the mast 1.
Moreover, in this embodiment, the axis 43 of suspension of the balance weight 14, the axis 42 of tilting motion, and the axis 70 of the tubes 53 which is the axis of suspension of the recuperator 4, are contained in the same plane or so-called principal plane PP of the tilting structure. Furthermore, steps are taken to ensure that the center of gravity of the tilting structure 2a, 2b, 2c is located in the principal ~ 2 ~
plane PP.
Thus the tilting structure constitutes a balance. In other words, the downward vertical force to be applied to the axis 70 in order to ensure that the tilting structure is in equilibrium about the axis 42 of tilting motion is the same irrespective of the inclination of the plane PP about the tilting axis 42.
On the contrary, in the example of FIGS. 7 to 9, by virtue of the particular position of the center of gravity G of the moving system, the downward vertical force to be applied to the axis 70 in order to balance the tilting structure was lower in value as the recuperator was closer to the ground.
Moreover, ln the example considered, the suspension of the recuperator is identical with that of the previous example except for the fact that the tubes 53 are attached to the fastening member 2d. The tubes 53 and 54 have the same diameter.
The loop suspension system 55 causes the main beam 7 to rotate about its own axis and about the principal axis 71 of the recuperator 4 while the tilting structure 2a, 2b, 2c pivots about the tilting axis 42 at the same time.
- FIGS. 12 and 13 illustrate schematically this effect of rotation of the recuperator 4 in a machine provided with suspension means 55 arranged in a first manner in which the loops have an oval configuration as in FIGS. 7 to 9.
The center of gravity of the recuperator is located on the axis 71 which will be designated as the "correction axis" for reasons which will become apparent hereafter.
When there is no wind, the correction axis 71 is located vertically beneath the suspension axis 70.
The fixing members 56, 57 which prevent the loops 55 ; 2 ~ 2 from sliding around the tubes 53 and 54 are placed in such a manner as to ensure tha-t, when the tilting structure 2a, 2b, 2c is in the light-wind position and when there is no wind, the axes 6a of the rotors are horizontal.
In the event of wind, as long as the tilting structure remains in the light-wind position, the two parallel strands of each loop 55 are inclined so as to be parallel to the resultant tension T but, as can readily be verified, the axes 6a of the rotors 6 remain horizontal ~FIG. 12) by virtue of the equality of diameter between the tubes 53 and 54. In other words, with an assembly of this type, the angle made by the axes of the rotors 6a with the principal plane PP is constant. In consequence, as illustrated schematically in FIG. 7, when the plane PP is inclined in the direction in which the recuperator 4 comes closer to the ground, the axis 6a of the rotor is also inclined.
This has the effect of reducing the cross-sectional area of the airstream which passes through each rotor and therefore of reducing the resultant aerodynamic drag.
The power collected by the machine is reduced even further since the axis of the rotors is no longer parallel to the wind.
Thus, when the machine is in a state of equilibrium which is different from the light-wind position, the aerodynamic drag on the recuperator is higher than the maximum drag in the light-wind position (if this were not the case, the machine would return to the light-wind position). However, the power is collected by the machine with lower efficiency and therefore remains substantially the same as the maximum power in the light-wind position~
The suspension loops can be arranged in a different manner as shown in FIGS. 14 and 15. In the absence of wind, the situation of the recuperator 4 with respect to the tilting structure 2 is identical with the situation illustrated in FIG. 5, the sole difference being that the suspension loops are crossed in a figure of eight.
By virtue of the fact that the loops 65 are each designed in a figure of eight and the fact that the axis 71 is positioned with respect to the axis 70 according to the orientation of the resultant tension, a rotation of the tilting structure 2a, 2b, 2c in the presence of a high wind 101 causes a rotation in the opposite direction of the tube 54 which is rigidly fixed to the main beam 7 of the recuperator 4, thus tilting this latter in the direction opposite to the inclination obtained in the first mode of arrangement of the suspension loops.
These modes of arrangement of the suspension loops produce an automatic adaptation of the power of the machine by means of a flexible suspension which ensures decoupling between on the one hand the rotors which produce vibrations and on the other hand the mast 1 and the frame 2.
In the second arrangement of the loops (FIGS.
14 and 15), the axes 6a are inclined if the axis 71 moves away from a position vertically beneath the axis 70~ In consequence, in the event o~ a gust of wind, this second arrangement produces a dodging movement on the part of the rotors 6 while waiting for the tilting structure 2a, 2b, 2c to be re-positioned about the tilting axis 42.
As can readily be understood, the present invention is not limited to the examples described and different arrangements can be made in these examples.
Provision may thus be made for restoring means other than a balance weight such as one or a 2 ~
number of restoring springs, for example. Stops other than the wheels 50 can be contemplated such as, for example, a sliding contact of the balance weight on a suitable track.
In the examples of FIGS. 11 to 15, the diameters of the tubes 53 and 54 can be different in order to obtain a predetermined dependence relation between the angles made with the principal plane PP by the axes 6a and by the strands of the loop 55.
It is even possible to achieve a more elaborate function by designing at least one of the tubes 53 and 54 in the form of a cam having the shape of an ellipse, for example. Each orientation of the plane PP results from a predetermined aerodynamic force which in turn corresponds to a predetermined angle of the strands of the loop 55 with respect to the vertical and consequently with respect to the plane PP. Thus, to give the axes 6a a predetermined orientation with respect to the plane PP as a function of the angle between the strands of the loop 55 and the plane PP is equivalent to giving the axes 6a a predetermined orientation with respect to the ground as a function of the inclination of the plane PP. It is thus possible among other things to maintain the axes 6a substantially horizontal irrespective of the inclination of the tilting structure. In the example of FIGS. 7 to 9, it is accordingly no longer necessary to control the angular position of the tube 53 with respect to the tilting structure as a function of the inclination of this latter.
The energy conversion means could be so arranged as to supply alternating current to a lamp which serves to illuminate the vanes of the rotors in order to animate an advertisement or the like which is carried by the vanes. The frequency of the current is .
2 ~
substantially proportional to the speed of rotation of the vanes. In addition, steps are taken to ensure that a whole number of electric half-waves corresponds substantially to an angle of rotation of each rotor equal to an angular pitch between two vanes of the rotor.
Thus at night, an advertisement or the like which is carried by the vanes forms a fi~ed image or an image which rotates relatively slowly in one direction or in the other. The machine equipment of this type is shown . 10 in chain-dotted lines in FIG. 3 with two lamps 40 which are carried by the frame 2 and each of which illuminates one of the rotors 6. In a manner which has not been illustrated, the lamps 40 are supplied between one of the conductors 17 and ground, or between two conductors 17.
2 ~
The object of the invention is to propose an air machine of the type indicated at the outset, which permits high energy production over a wide range of wind forces while being well protected against climatic hazards.
According to the first aspect of the invention, the method for regulating an air machine for the conversion of wind energy to useful energy, of the type comprising a rotary energy recuperator which is capable of moving to different heights, is characterized in that the recuperator is positioned in a substantially stable manner at a height with respect to the ground which is a decreasing function of the force of the wind.
According to the second aspect of the invention, the air machine for the conversion of wind energy to useful energy, comprising a mast, a rotary energy recuperator, means for height displacement of the recuperator with respect to the mast under the action of the aerodynamic force exerted on the recuperator and in opposition to restoring means, and an energy conversion device connected to the recuperator in order to be driven in rotation by the recuperator, is characterized in that the height displacement means are designed to position the recuperator in a substantially stable manner at a height above ground which is a decreasing function of the force of the wind.
The invention is based on the observation that the force of the wind is lower as the wind is closer to the ground. The recuperator of the machine in accordance with the invention comes into position and operates closer to the ground as the wind is stronger.
The machine can be dimensioned so as to deliver its rated power with a relatively light wind which will be collected at a substantial height above ground and so as to deliver substantially the same power in a high wind which is collected much nearer the ground.
Thus the collected power is often close in value to the rated power and the second result achieved is that the recuperator is sheltered or in other words close to the ground in the event of a high wind.
The method in accordance with the invention is such that the height of positioning of the recuperator is a decreasin~ function of the force of the windO This does not rule out the possibility that the height of positioning of the recuperator can be a function of - other variables. In particular, for a given force of wind, the height of the recuperator may vary as a function of the power required of the machine by users of the energy produced.
Preferably, when the height displacement means comprise a tilting structure which carries the recuperator at a distance from a substantially horizontal axis of tilting motion on which said tilting structure is articulated with resPect to the maqt, the restoring means are provided by an arrangement whereby a vertical ideal plane containing the axis of tilting motion extends between the recuperator and the center of gravity of the moving system (that is to say, for example, the assembly comprising the tilting structure, the recuperator and a balance weight) which is capable of moving about the axis of tilting motion.
The result thereby achieved is to minimize the bending moments sustained by the mast and therefore to minimize the cost of the mast and the cost of its installation. On the contrary, in FR - A - 2 568 948, the spring which partially locks the tilting-motion articulation increases the bending moment sustained by the mast.
In order to limit the upward travel of the recuperator, provision is preferably made for bearing `- 201~2~
means which rest on the ground when the recuperator is in the light-wind position.
In accordance with patent FR-A- 2 569 948, the bearing means rest on the mast and further increase the bending moment sustained by the mast.
It is also preferred that the machine comprises flexible supporting means for suspension of the recuperator. By virtue of these flexible means, the vibrations resulting from operation of the recuperator are decoupled from the remainder of the structure, thus avoiding the risk that these vibrations may produce dangerous resonances within the frame and the mast.
Further particular features and advantages of the invention will be brought out by the description given hereinafter.
In the accompanying drawings which are given as non-limitative exampleS:
- FIG. 1 is a view in perspective of a machine in accordance with the invention ;
- FIG. 2 is a partial explanatory view in elevation of the machine of FIG. 1 ;
- FIG. 3 is a schematic top view of the machine of FIGS. 1 and 2 ;
- FIG. 4 is a view which is similar to FIG. 3 but relates to a second embodiment ;
- FIG. 5 is a view in side elevation of a water tower equipped with a wind engine in accordance with a third embodiment of the invention ;
- FIG. 6 is a top view of the water tower of FIG. 5 ;
- FIG. 7 is a view in perspective showing a fourth embodiment of the machine in accordance with the invention ;
- FIG. 8 is a view in elevation of the machine of FIG. 7, the recuperator being in the top posi-tion ;
` ` ~ 2~9~2 - FIG. 9 is a view to a larger scale showing a portion of FIG. 8, in the event of wind ;
- FIG. 10 is a schematic top view of a fifth embodiment of the invention ;
- FIG. 11 is a view in elevation of the fifth embodiment of the invention ;
- FIG. 12 is a detail of FIG. 11, in the event of wind ;
- FIG. 13 is a schematic view in elevation showing the air machine of FIG. 11, in the presence of a violent wind ; and - FIGS. 14 and 15 are views which are similar to FIGS. 11 and 13 ~ut relate to a sixth embodiment.
In the example shown in FIG. 1, the wind engine comprises a mast 1 anchored to the ground so as to extend vertically upwards from the ground, and a frame 2 which is mounted at the top of the mast 1 so as to be orientable with respect to the mast 1 about a vertical central axis 3 of the mast 1.
The orientable frame 2 carries an energy recuperator 4 comprising two vane-type rotors 60 The central shafts of said rotors are freely mounted for rotation about parallel axes on a mounting support 7.
A peripheral ring 8 of each rotor 6 forms an inertia fly-wheel contributing to regulation of the machine and drives a respective asynchronous machine 9 by meshing or by friction so as to convert the wind energy collected by the machine to electric current.
The asynchronous machines 9 are capable of rotating freely with respect to each other.
The recuperator 4 is connected to the mast 1 in such a manner as to ensure that the aerodynamic forces exerted on the recuperator 4 and in particular on its rotors 6 under the action of wind, the direction of which is represented by the arrow V, result in a 2 ~ 2 variation in the geometry of the machine so that the recuperator is always located in an optimum position with respect to the wind, taking into account the maximum permissible power of the machine, the maximum speed of rotation of t~le rotors, and the required power.
To this end, the recuperator 4 is suspended from the orientable frame 2 by flexible means 11 which are passed over guide pulleys 12 and 13 rotatably carried by the frame 2. At their ends remote from the mounting support 7, the flexible means 11 are attached to a balance weight 14. In the example, the flexible means ll consist of two cables 16 which extend parallel to each other in order to maintain the axes of the two rotors 6 in the same horizontal plane and to maintain them substantially parallel to, and equidistant fro~ a vertical plane P(FIG. 3) which contains the axis 3. It is readily apparent that, since these cables are flexible, positioning of the recuperator 4 is not strictly accura~e. However, said positioning is sufficient in practice since the resultant of the aerodynamic forces exerted on the recuperator does not haveany large component which would be capable of acting between the recuperator and the frame 2 so as to destabilize the recuperator with respect to the frame. On the other hand, the cables 16 are so arranged as to ensure that the only restoring force which acts in opposition to a pendular motion of the recuperator 4 about an axis perpendicular to the plane P is the force which results from the weight of the recuperator 4 and from the energy conversion means 9 which are coupled to this latter.
The mass of this assembly is smaller than the mass of the balance weight 14. In consequence, when no other forces are present and in particular when there is no wind, the recuperator 4 assumes the top position ` -` 2~92~2 - --7~
close to the frame 2 whilst the balance weight 14 is close to the ground.
By contrast, as shown in FIG. 2, when an aerodynamic force F2 is exerted on the recuperator 4, said force which is directed substantially horizontally, is added vectorially to the weight P of the assembly consisting of recuperator 4 and generator 9 in order to give the cables 16 a tension T which is higher at absolute value than the weight P. In view of the fact that the aerodynamic force which may be exerted on the recuperator increases with the height above ground ~FIG. 2 shows the force Fl in the vicinity of the : ground, the force F2 at a mean height above ground and the force F3 at a maximum height of the recuperator), the recuperator 4 stabilizes at a height at which the tension T of the cables 16 at the end nearest the recuperator is equal to the weight of the balance weight 14.
Moreover, as shown in FIG. 2, the angle of slope of the cable 16 above the recuperator 4 departs from the vertical to a greater extent as the aerodynamic force is larger. Thus, in the event of a sudden gust of wind of gale force, the recuperator dodges the gust of wind in two ways, on the one hand by moving away from the mast 1 in the direction of the wind and on the other hand by moving closer to the ground until the tension T again becomes equal to the weight of the balance weight 14.
If the power required by users and delivered by the generators 9 is relatively low, the adjustment carried out by the aforementioned equilibrium between the balance weight 14 and the recuperator may correspond to an excessive speed of rotation of the rotors 6.
As shown in FIG. 3, this drawback can be avoided by mounting a frequency meter 18 on one of the 2 ~ 5 ~
three phase leads 17 of the output line of the generators 9. The output of said frequency meter 18 is directed to one o~ the inputs 19 of a comparator 21, the other input 22 of which is connected to a set point. The output 23 of the comparator 21 controls a servomotor 24 which is mounted on the sha~t of the pulleys 12 and, when it is activated, imparts a torque to these pulleys in the direction of downward displacement of the recuperator 4 towards the ground. It may also happen that the speed of rotation of the rotors 6 is insufficient. This may resu]t from an overload produced by the users. It is possible to guard against such a drawback by providing a circuit-breaker which is capable of putting all or part of the installation out of circuit.
The speed of the rotors 6 may also be insufficient by reason of practically total absence of wind. In this case, even if the recuperator 4 is placed at the maximum height above ground, the speed of rotation of the rotors may be insufficient and the power delivered may be relatively low. Within the limits of a self-contained installation (the machine is connected only to a certain number of well-determined utilization points), it is possible to ensure that the circuit-breaker is responsive to the frequency of the current delivered by the generators 9 and not to the intensity of this current.
In the case of a machine connected to a power supply system 26 (FIG. 4), it is proposed in accordance with the invention to mount capacitors 27 between the phase leads 17 (or alternatively between each phase lead 17 and a neutral point). Moreover, each generator 9 is disposed in engagement with the associated rotor 6 by means of a free-wheel device 28 which enables the generator to rotate at a higher speed than -the - 2 1~ 5 2 g associated rotor. Since the generators 9 are ` asynchronous generators, then in the event of insufficient speed imparted by the rotor 6, the generators 9 then operate as motors which rotate on no load since they do not have to drive the associated rotor 6 by virtue of the free wheels 28. This prevents the generators 9 from impairing the current delivered to users by the power supply system 26.
The recuperator 4 is positioned laterally with respect to the axis 3 of pivotal displacement of the frame 2 in such a manner as to ensure that the centroid B (FIG. 4) of application of the resultant of the aerodynamic forces exerted on the recuperator 4, in particular the forces Fa and Fb exerted on the rotors 6, is located at a distance from the axis 3. Thus the recuperator 4 has a permanent tendency to come into position behind the mast 1 with respect to the direction of the wind by rotational displacement of the frame 2 about the axis 3.
More s~i~ ly, when the line of action L of the resultant F does not pass through the axis 3, it exerts about the axis 3 a rotational moment which tends to cause rotation of the frame and consequently of the recuperator 4 about the axis 3. This situation (shown in FIG. 4) is therefore unstable. In the situation shown in chain-dotted lines, this is a stable situation in which the resultant F has a line of action which passes through the axis 3, the direction of the wind V
being naturally parallel to this line of action. By virtue of the symmetry of the recuperator 4 with respect to the plane P, P is accordingly parallel to the direction of the wind.
Since the centroid B is substantially located in the common plane of the rotors 6, the aforementioned distance between the centroid B and the axis 3 is ~ 2~2~2 achieved by giving the arm 2 a signi~icant length in the plane P, in particular by positioning the axis of the pulleys 12 a~ a significant distance from the axis 3 of pivotal displacement. The position of the axis of the pulleys 13 is substantially symmetrical with that of the axis of the pulleys 12 with respect to the axis 3. Thus the vertical forces exerted on the arm 2 on each side of the axis 3 are substantially the same and the arm 2 does not have to resist a tilting couple.
In order to ensure better symmetry of the forces applied on the machine, the two rotors 6 have vanes which are differently oriented so that they rotate in opposite directions together with the generators 9 which are also disposed symmetrically with respect to the plane P. The fact that the aerodynamic forces exerted on the recuperator 4 are perfectly symmetrical on each side of the plane P and are located at a significant distance on each side of the plane P endows the recuperator 4 with high stability despite the fact that it is suspended only from two cables 16.
In the example shown in FIGS. 5 and 6, the mast 1 is a water tower. Only the differences with respect to the previous example will be described. In this example, the generators 9 supply a pump located at the base of the water tower. The connection between the generators 9 and the pump (not shown) located within the water tower is established by means of a flexible electric wire 28 connected electrically via a rotary contact 29 to a connector located within the hollow interior of the pivot 31 which is secured to the mast 1 and on which the orientable frame 2 is pivotally mounted.
In a machine o. small height, the energy conversion means 9 could be a pump connected by flexible pipes and rotary seals within the pivot 31 which would contain two tubes, one for drawing water by suction and 2a~9~
the other for discharging water.
As shown diagrammatically in FIG. 6, the frame 2 can be rig.idly fixed to two deflectors 32 placed between the body of the water tower 1 and the rotors 6, the function of said deflectors being to guide the airstreams 33 towards the rotors 6.
In the case of the application to a water tower, the speed regulation of the machine is not critical if it is certain that ~here is always a possibility of pumping water to the top of the water tower. It is in fact possible to ensure that, a-t the rated speed of the pump, the power consumed by this latter corresponds to the electric power delivered by the generators 9 when the rotor rotates at its rated speed and when the recuperator is in equilibrium with the balance weight 14. Should the wind be too light, it is not a serious matter if the pump output decreases.
In the case of a water tower, the machine in accordance with the invention is therefore, in its basic principles, completely regulated by the means for self-positioning about the axis 3 and by the means for self-positioning in height by equilibrium with the balance weight 14.
The example of FIGS. 7 and 8 will be described only in regard to the differences between this latter and the example of FIG. 1. The orientable frame 2 comprises a turret 31 which covers the mast 1 and a tilting structure 2a, 2b, 2c which is pivoted to the turret 31 about a horizontal axis 42 of tilting motion by means of an articulation 41. The tilting axis 42 intersects the axis 3 of pivotal displacement at the top of the mast l.
The tilting structure comprises a first individual frame 2a and a second individual frame 2b 2~9~
which are pivoted to each other about the tilting axis 42 and which extend respectively on each side of a vertical plane PV containing the tilting axis 42.
Under the action of their own weight and of the weight of the elements which they carry and which will be described hereinafter, the two individual frames 2a and 2b each tend to pivot downwards, that is to say in opposite directions about the tilting axis 42.
In order to guard against this tendency and to couple the two individual frames 2a and 2b in rotation about the tilting axis 42, the tilting structure comprises in addition two traction cables 2c mounted in parallel, each cable being anchored to the end 2d of the frame 2a and to the end 2e of the frame 2b which are remote from the tilting axis 42. The cables 2c extend above the tilting axis 42 perpendicularly to this latter. Thus in regard to the loads to which it is subjected, the assembly constituted by the frames 2a and 2b and the cables 2c behaves as a rigid structure while being constituted by elements of relatively small size which can be readily assembled in situ. The end 2d of the individual frame 2a is constituted by a fastening member from which the recuperator 4 is suspended.
The fastening member 2d comprises, at that end which is directed laterally away from the plane PV, a tube 53 having a so-called suspension axis 70 which is substantially horizontal and parallel to the axis 42.
Connecting means 16 which are closed in loop, such as two straps, chains or belts mounted in parallel connect the tube 53 to the mounting support 7 and, more precisely, surround the tube 53 and the main beam of the mounting support 7. Said main beam is a tube having an axis 71 which is substantially horizontal and parallel to the axes 70 and 42.
Moreover, the loop connection means 16 are `~ 2 ~
prevented from sliding in the circumferential direction with respect to the tube 53 and with respect to the main beam of the mounting support 7. In this example, the tube 53 is capable of rotating about its axis 70 with respect to the fastening member 2d and its angular position is controlled as a function of the inclination of the structure 2a, 2b, 2c about the tilting axis 42 so as to ensure that the axes of the rotors 6 are horizontal irrespective of said inclination. In the event of wind (FIG. 9), the suspension 16 tilts under the action of the horizontal forces F3 which are exerted on the recuperator but maintains the recuperator in the position in which the axes of the rotors are horizontal. The center of gravity of the recuperator 4 is located on the axis 71 of the mounting support 7, with the result that the weight of the recuperator 4 continuously tends to place the axis 71 in the vertical plane containing the axis 70 and does not exert any torque about the axis 71.
A balance weight 14 is connected to the end 2e of the second individual frame 2b by means of an articulation 52 which permits free rotational displacement of the balance weight 14 about a pivotal axis 43 which is parallel to the axis 42 and distant from the plane PV. As shown in FIG. 8, the balance weight 14 is such that the center of gravity G of the moving svstem (comprising the tilting structure 2a, 2b, 2c, the balance weight 14 and the recuperator 4) is located on the same side of the plane PV as the balance weight 14.
Thus, in the absence of forces other than gravity forces on the moving system 2a, 2b, 2c, 4, 14, in particular when there is no wind, the recuperator 4 takes up the so-called "light wind" top position at a height above ground which is distinctly greater than 2~2~2 that of the axis 42 of tilting motion. The tilting structure 2a, 2b, 2c is in that case steeply inclined and the balance weight 14 is close to the ground. In this situation, the center of gravity G of the moving system is located at a greater height above ground than the tilting axis 42.
When wind is blowing, there is exerted on the moving system 2a, 2b, 2c, 4, 14 an aerodynamic force F3 (FIG. 9) which is considered for the sake of simplici-ty as located in the plane of the axes 6a of the rotors 6 of the recuperator 4. In actual fac-t, taking into account the aerodynamic forces exerted on the frames 2a and 2b, said force is located slightly lower than the axes 6a when the tilting structure is in the light-wind position and at a slightly greater height than the axes 6a when the frame 2a makes a larger angle with the plane PV as will be seen hereafter.
The force F3 applies to the tilting structure about the tilting axis 42 a moment which is orien-ted in the direction opposite to the moment applied by the weight P of the moving system at the center of gravity G.
Thus the recuperator 4 is located in the top position until the wind attains the velocity corresponding to the rated power of the machine.
When the wind attains this intensity threshold, the torque exerted by the aerodynamic force about -the tilting axis 42 exceeds the torque exerted in the opposite direction about the same axis by the weight of the moving system 2a, 2b, 2c, 4, 53 and the moving system pivots about the tilting axis 42 in the direction of downward displacement of the recuperator 4 towards the ground, up to a position of equilibrium in which the moment of the aerodynamic force and the moment of the weight of the moving system about the tilting axis 42 are equal and opposite, that is to say when the torque i 2 ~ 2 exerted by the aerodynamic drag has decreased to a sufficient extent to be no longer in excess with respect to the torque exerted by the weight of the moving system.
This new equilibrium can be found by reason of the fact that, when the tilting structure pivots about the axis 42 in the direction of downward displacement of the recuperator towards the ground, the aerodynamic force F3 decreases in order to become a new force F2 of smaller magnitude since the intensity of the wind is an increasing function of the height above ground.
If the torque exerted by the weight were independent of the inclination of the moving system about the tilting axis 42, the new equilibrium would be attained when the torque exerted by the aerodynamic drag of the moving system has also returned to the threshold value above which the moving system leaves the light-wind position. However, since the lever arm length available to the action of aerodynamic drag decreases when the moving system comes closer to the ground, the aerodynamic force to which this threshold value of torque of the aerodynamic force would correspond would be of greater magnitude as the recuperator would be nearer the ground. Under these conditions, the power delivered by the machine would tend to be higher as the recuperator 4 is nearer the ground. These disadvantages are avoided by vixtue of the particular position of the center of gravity G of the moving system 2a, 2b, 2c, 4, 53 which is located at a slightly higher altitude than that of the tilting axis 42 when the tilting structure is in the light-wind position.
Thus, when the tilting structure pivots towards another position about the tilting axis 42, the vertical line Y (FIG. 8J which passes through the center of gravity G comes closer to the axis 42 and the torque 2~2~2 exerted by the weight of the moving system consequently decreases.
In consequence, the aerodynamic torque which is necessary in order to balance the torque due to the weight also decreases. Thus it is possible to ensure that the aerodynamic drag exerted on the recuperator varies little as a function of the inclination of the tilting structure In the example shown in FIGS. 7 to 9, the particular position of the center of gravity G is obtained by giving an upwardly directed concavity to the broken line which passes through the axes 43, 42, 71.
In the embodiment of FIGS. 10 and 11, the balance weight 14 is provided with rolling means 50.
These rolling means can comprise one or a number of wheels such as, for example, two wheels 50a, 50b joined together by means of an axle 50c, the axis of which intersects the axis 3, at least when the tilting structure is in the light-wind position as shown in FIG. 11, in which case the wheels 50a, 50b bear on two rails 58a, 58b of a circular track 80 whose axis coincides with the axis 3 of pivotal displacement, said track being arranged on the ground around the mast 1.
Application of the wheels 50a, 50b on the track 80 defines the light-wind position of the tilting structure.
In this positionr the balance weight 14 does not exert any torque on the mast 1.
Moreover, in this embodiment, the axis 43 of suspension of the balance weight 14, the axis 42 of tilting motion, and the axis 70 of the tubes 53 which is the axis of suspension of the recuperator 4, are contained in the same plane or so-called principal plane PP of the tilting structure. Furthermore, steps are taken to ensure that the center of gravity of the tilting structure 2a, 2b, 2c is located in the principal ~ 2 ~
plane PP.
Thus the tilting structure constitutes a balance. In other words, the downward vertical force to be applied to the axis 70 in order to ensure that the tilting structure is in equilibrium about the axis 42 of tilting motion is the same irrespective of the inclination of the plane PP about the tilting axis 42.
On the contrary, in the example of FIGS. 7 to 9, by virtue of the particular position of the center of gravity G of the moving system, the downward vertical force to be applied to the axis 70 in order to balance the tilting structure was lower in value as the recuperator was closer to the ground.
Moreover, ln the example considered, the suspension of the recuperator is identical with that of the previous example except for the fact that the tubes 53 are attached to the fastening member 2d. The tubes 53 and 54 have the same diameter.
The loop suspension system 55 causes the main beam 7 to rotate about its own axis and about the principal axis 71 of the recuperator 4 while the tilting structure 2a, 2b, 2c pivots about the tilting axis 42 at the same time.
- FIGS. 12 and 13 illustrate schematically this effect of rotation of the recuperator 4 in a machine provided with suspension means 55 arranged in a first manner in which the loops have an oval configuration as in FIGS. 7 to 9.
The center of gravity of the recuperator is located on the axis 71 which will be designated as the "correction axis" for reasons which will become apparent hereafter.
When there is no wind, the correction axis 71 is located vertically beneath the suspension axis 70.
The fixing members 56, 57 which prevent the loops 55 ; 2 ~ 2 from sliding around the tubes 53 and 54 are placed in such a manner as to ensure tha-t, when the tilting structure 2a, 2b, 2c is in the light-wind position and when there is no wind, the axes 6a of the rotors are horizontal.
In the event of wind, as long as the tilting structure remains in the light-wind position, the two parallel strands of each loop 55 are inclined so as to be parallel to the resultant tension T but, as can readily be verified, the axes 6a of the rotors 6 remain horizontal ~FIG. 12) by virtue of the equality of diameter between the tubes 53 and 54. In other words, with an assembly of this type, the angle made by the axes of the rotors 6a with the principal plane PP is constant. In consequence, as illustrated schematically in FIG. 7, when the plane PP is inclined in the direction in which the recuperator 4 comes closer to the ground, the axis 6a of the rotor is also inclined.
This has the effect of reducing the cross-sectional area of the airstream which passes through each rotor and therefore of reducing the resultant aerodynamic drag.
The power collected by the machine is reduced even further since the axis of the rotors is no longer parallel to the wind.
Thus, when the machine is in a state of equilibrium which is different from the light-wind position, the aerodynamic drag on the recuperator is higher than the maximum drag in the light-wind position (if this were not the case, the machine would return to the light-wind position). However, the power is collected by the machine with lower efficiency and therefore remains substantially the same as the maximum power in the light-wind position~
The suspension loops can be arranged in a different manner as shown in FIGS. 14 and 15. In the absence of wind, the situation of the recuperator 4 with respect to the tilting structure 2 is identical with the situation illustrated in FIG. 5, the sole difference being that the suspension loops are crossed in a figure of eight.
By virtue of the fact that the loops 65 are each designed in a figure of eight and the fact that the axis 71 is positioned with respect to the axis 70 according to the orientation of the resultant tension, a rotation of the tilting structure 2a, 2b, 2c in the presence of a high wind 101 causes a rotation in the opposite direction of the tube 54 which is rigidly fixed to the main beam 7 of the recuperator 4, thus tilting this latter in the direction opposite to the inclination obtained in the first mode of arrangement of the suspension loops.
These modes of arrangement of the suspension loops produce an automatic adaptation of the power of the machine by means of a flexible suspension which ensures decoupling between on the one hand the rotors which produce vibrations and on the other hand the mast 1 and the frame 2.
In the second arrangement of the loops (FIGS.
14 and 15), the axes 6a are inclined if the axis 71 moves away from a position vertically beneath the axis 70~ In consequence, in the event o~ a gust of wind, this second arrangement produces a dodging movement on the part of the rotors 6 while waiting for the tilting structure 2a, 2b, 2c to be re-positioned about the tilting axis 42.
As can readily be understood, the present invention is not limited to the examples described and different arrangements can be made in these examples.
Provision may thus be made for restoring means other than a balance weight such as one or a 2 ~
number of restoring springs, for example. Stops other than the wheels 50 can be contemplated such as, for example, a sliding contact of the balance weight on a suitable track.
In the examples of FIGS. 11 to 15, the diameters of the tubes 53 and 54 can be different in order to obtain a predetermined dependence relation between the angles made with the principal plane PP by the axes 6a and by the strands of the loop 55.
It is even possible to achieve a more elaborate function by designing at least one of the tubes 53 and 54 in the form of a cam having the shape of an ellipse, for example. Each orientation of the plane PP results from a predetermined aerodynamic force which in turn corresponds to a predetermined angle of the strands of the loop 55 with respect to the vertical and consequently with respect to the plane PP. Thus, to give the axes 6a a predetermined orientation with respect to the plane PP as a function of the angle between the strands of the loop 55 and the plane PP is equivalent to giving the axes 6a a predetermined orientation with respect to the ground as a function of the inclination of the plane PP. It is thus possible among other things to maintain the axes 6a substantially horizontal irrespective of the inclination of the tilting structure. In the example of FIGS. 7 to 9, it is accordingly no longer necessary to control the angular position of the tube 53 with respect to the tilting structure as a function of the inclination of this latter.
The energy conversion means could be so arranged as to supply alternating current to a lamp which serves to illuminate the vanes of the rotors in order to animate an advertisement or the like which is carried by the vanes. The frequency of the current is .
2 ~
substantially proportional to the speed of rotation of the vanes. In addition, steps are taken to ensure that a whole number of electric half-waves corresponds substantially to an angle of rotation of each rotor equal to an angular pitch between two vanes of the rotor.
Thus at night, an advertisement or the like which is carried by the vanes forms a fi~ed image or an image which rotates relatively slowly in one direction or in the other. The machine equipment of this type is shown . 10 in chain-dotted lines in FIG. 3 with two lamps 40 which are carried by the frame 2 and each of which illuminates one of the rotors 6. In a manner which has not been illustrated, the lamps 40 are supplied between one of the conductors 17 and ground, or between two conductors 17.
Claims (22)
1. Method for regulating an air machine for the conversion of wind energy to useful energy, of the type comprising a rotary energy recuperator (4) which is capable of moving to different heights, characterized in that the recuperator is positioned in a substantially stable manner at a height above ground which is a decreasing function of the force of the wind.
2. Air machine for the conversion of wind energy to useful energy for the application of the method in accordance with claim 1, comprising a mast (1), a rotary energy recuperator (4), means (2, 11, 14) for height displacement of the recuperator (4) with respect to the mast (1) under .the action of the aerodynamic force (F, F2) exerted on the recuperator and in opposition to restoring means, and an energy conversion device (9) connected to the recuperator (4) in order to be driven in rotation by the recuperator (4), character-ized in that the height displacement means (2, 11, 14) are designed to position the recuperator (4) in a substantially stable manner at a height above ground which is a decreasing function of the force of the wind.
3. Machine in accordance with claim 2, characterized in that, as said height displacement means, the recuperator is connected to a balance weight (14) by flexible means (11) which, between the recuperator (4) and the balance weight (14), pass around guide means (12, 13) which are supported at least indirectly by the mast (1).
4. Machine in accordance with claim 3, characterized in that the mass of the balance weight (14) is chosen so as to ensure that the recuperator (4) is returned to the top position in the absence of wind.
5. Machine in accordance with one of claims 3 or 4, characterized in that the flexible means (11) comprise two cables (16) mounted in parallel and separated laterally from each other.
6. Air machine in accordance with one of claims 3 to 5, characterized in that the guide means (12) are made dependent on the variations in speed of rotation of the recuperator (4) or of the energy conversion device (9) in order to adjust the height of the recuperator (4) above ground in the direction of regulation of said speed of rotation.
7. Machine in accordance with one of claims 3 to 6, in which the recuperator is connected to the mast by means of a frame (2) which is orientable about a vertical axis (3) with respect to the mast (1), characterized in that the frame (2) carries the guide means (12, 13) which comprise at least one pulley (12) above the recuperator (4) and at least one pulley (13) located on the other side of the vertical axis (3) above the balance weight (14).
8. Machine in accordance with one of claims 2 to 5, characterized by means (18, 21, 24) for limiting the speed of rotation of the recuperator (4) independently of the aerodynamic force (F) to which the recuperator (4) is subjected.
9. Machine in which the height displacement means comprise a tilting structure (2a, 2b, 2c) which carries the recuperator (4) at a distance from a substantially horizontal axis (42) of tilting motion, in which said tilting structure is articulated with respect to the mast, characterized in that the restoring means are provided by an arrangement whereby a vertical ideal plane (PV) containing the axis (42) of tilting motion extends between the recuperator (4) and the center of gravity (G) of the moving system (2a, 2b, 2c, 14, 4) which is capable of moving about the axis (42) of tilting motion.
10. Machine in accordance with claim 9, characterized in that the center of gravity (G) of the moving system which is capable of displacement about the axis (42) of tilting motion is located at a greater height than the axis (42) of tilting motion.
11. Machine in accordance with one of claims 9 or 10, characterized in that the tilting structure comprises two elementary frames (2a, 2b) one of which is connected to the recuperator and the other of which is connected to a balance weight, said frames being pivoted to each other about the axis (42) of tilting motion and connected to each other by rigidifying means (2c) which extend above the tilting axis and work in traction.
12. Machine in accordance with claim 11, characterized in that the rigidifying means (2c) comprise at least one traction cable.
13. Machine in accordance with one of claims 9 to 12 comprising in addition correcting means (2d, 16) for positioning the recuperator angularly about a correction axis (71) which is substantially parallel to the tilting axis (42) as a function of the angular position of the tilting structure about the -tilting axis, characterized in that it comprises in addition supporting means (16) for suspending the recuperator (4) from the tilting structure, the correcting means being adapted to orient the recuperator (4) in suspension with respect to the tilting structure (2a, 2b, 2c) about the correction axis (71) as a function of an angle made between the tilting structure (2a, 2b, 2c) and the supporting means (16) about a suspension axis (70).
14. Machine in accordance with claim 11, characterized in that the correcting means are actuated by the weight of the recuperator.
15. Machine in accordance with claim 14, characterized in that the suspension means (16) comprise at least one flexible element (55) in the form of a closed loop surrounding a supporting member (53) which is rigidly fixed to the tilting structure and a supporting member (54) which is rigidly fixed to the recuperator (4), and in that said correcting means comprises means preventing any peripheral sliding movement of the flexible element with respect to the two supporting members so that when the tilting structure pivots about its axis (42) of tilting motion, the assembly constituted by the recuperator (4) and the flexible element (55) pivot with respect to the tilting structure under the action of the forces (P, F3) exerted on the recuperator (4) and the flexible element which is coupled with the supporting member (53) of the tilting structure orients the recuperator (4) about the correction axis (71).
16. Machine in accordance with claim 15, characterized in that the flexible element (65) is closed in a crossed loop, generally in the shape of a figure of eight.
17. Machine in accordance with one of claims 13 to 16, characterized in that the correction axis (71) passes substantially through the center of gravity of the recuperator (4).
18. Machine in accordance with one of claims 2 or 8 to 11, characterized in that it comprises flexible means for the suspension of the recuperator.
19. Machine in accordance with one of claims 2 to 18, characterized in that the recuperator (4) comprises two rotors (6) placed side by side.
20. Machine in accordance with one of claims 2 to 19, comprising bearing means for limiting the upward travel of the recuperator, characterized in that said bearing means rest on the ground when the recuperator is in the light-wind position.
21. Machine in accordance with claim 20 in which the recuperator pivots about a vertical axis (3) associated with the mast, characterized in that the bearing means comprise rolling means (50) which, when the recuperator is in the light-wind position, bear on a circular track (80) supported on the ground around the mast (1).
22. Machine in accordance with one of claims 2 to 21, characterized in that its energy conversion device produces alternating current and supplies a device for illuminating its vanes in order to produce a stroboscopic effect.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002019252A CA2019252A1 (en) | 1990-06-19 | 1990-06-19 | Method for regulating an air machine for the conversion of wind energy to useful energy, and machine for carrying out said method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002019252A CA2019252A1 (en) | 1990-06-19 | 1990-06-19 | Method for regulating an air machine for the conversion of wind energy to useful energy, and machine for carrying out said method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2019252A1 true CA2019252A1 (en) | 1991-12-19 |
Family
ID=4145262
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002019252A Abandoned CA2019252A1 (en) | 1990-06-19 | 1990-06-19 | Method for regulating an air machine for the conversion of wind energy to useful energy, and machine for carrying out said method |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2019252A1 (en) |
-
1990
- 1990-06-19 CA CA002019252A patent/CA2019252A1/en not_active Abandoned
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