The present application claims priority to Italian Patent Application No. TO2011A000879, filed Oct. 3, 2011, incorporated herein in its entirety.
The present invention relates to a system for generating electrical energy from sea waves, of the type comprising a floating body and a gyroscope structure set thereon.
In known systems of the type described above, the first frame moves according to a movement of oscillation that is supplied by the gyroscopic force induced by the combination of the motion of roll (and/or pitch) of the floating body and of the motion of rotation of the rotor about its own axis. The movement of oscillation of the first frame is exploited by the electric-generator means for the production of electrical energy. In some solutions of a known type, the generator means are directly connected to the first frame to generate an a.c. signal, whilst in other solutions, between the first frame and the generator means, mechanical transmission means are provided designed to connect operatively together the first frame and the generator means only in one direction of rotation of the frame in such a way that the generator means will generate a variable-current signal but with constant sign. An example of the latter type of known solution is described in the U.S. Pat. No. 4,352,023.
The object of the present invention is to provide a system that is able to operate with an operating efficiency that is higher than those of the known systems indicated above. The object is achieved via a system of the type indicated at the beginning and characterized in that it comprises actuator means designed to control rotation of the first frame about the first axis, as a function of the angular position of the first frame in such a way that in operation the first frame will perform, about the first axis, complete rotations through 360°, in one and the same direction of rotation.
The present invention relates to a system for generating electrical energy from sea waves, of the type comprising a floating body and a gyroscope structure set thereon. The gyroscope structure comprises a first frame mounted so that it can turn with respect to the floating body about a first axis of rotation; and a rotor, which is mounted so that it can turn about a second axis of rotation, is carried by the first frame, and is substantially orthogonal to the first axis. The system further comprises electric-generator means operatively connected to the first frame for generating electrical energy as a result of rotation of the first frame about the first axis.
Further characteristics and advantages of the invention will emerge from the ensuing description with reference to the annexed drawings, which are provided purely by way of non-limiting example and in which:
a-4f illustrate the system of
a-5f are schematic illustrations of operating sequences of the system;
In the ensuing description, various specific details are illustrated aimed at an in-depth understanding of the embodiments. The embodiments may be provided without one or more of the specific details, or with other methods, components, materials, etc. In other cases, known structures, materials, or operations have not been described in detail so that the various aspects of the embodiments will not be obscured.
The references used herein are provided only for convenience and hence do not define the sphere of protection of the embodiments.
With reference to
In general, the system 10 comprises a floating body (not shown) and a gyroscope structure 4 set thereon and comprising a first frame 6 mounted so that it can turn with respect to the floating body about a first axis E; a rotor 8, which is mounted so that it can turn about a second axis of rotation Φ, is carried by the first frame, and is substantially orthogonal to the first axis. In various preferred embodiments, as in the one illustrated, the second axis of rotation is contained in a plane substantially orthogonal to the plane of floating of the floating body.
In the embodiment illustrated in the figures, the first frame 6 is directly mounted on a supporting structure 12, which is to be rigidly connected to the floating body; in the embodiment, the gyroscope structure 12 consequently has just one degree of freedom. In alternative embodiments, the first frame can, instead, be mounted—so that it can turn about the first axis—on a second frame, which is in turn mounted so that it can turn on the supporting structure about a third axis of rotation orthogonal to the first axis. Consequently, in the embodiment, the gyroscope structure has two degrees of freedom.
As is evident to a person skilled in the art, the gyroscope structure with one degree of freedom—of which, as has already been the, the figures illustrate just an example—enables exploitation only of the oscillations of the floating body that occur about an axis orthogonal to the axis of rotation of the first frame, and not also, instead, of the oscillations that occur about an axis parallel thereto. Consequently, in preferred embodiments, the floating body has, on the outer part of its hull, drift elements designed to orient the floating body in such a way that, during operation, the axis of the first frame is kept parallel to the direction of advance of the waves (namely, the axis of oscillation of the floating body will remain orthogonal to the axis of the first frame).
In various embodiments, as in the one illustrated, the first frame 6 has a structure substantially resembling a picture frame defining first portions 6′ for rotatable coupling, about the second axis, with the shaft of the rotor, and second portions 6″ for rotatable coupling, about the first axis, with the supporting structure 12.
In various embodiments, as in the one illustrated, the system comprises electric-generator means 14 connected to the first frame so as to exploit the kinetic energy associated thereto for generating electrical energy. The means will not be described herein in detail in so far as they are already widely known in the relevant art. For the reasons that will be evident in what follows to a person skilled in the art, the electric-generator means used in the system described herein are preferably of the rotary type.
In various embodiments, as in the one illustrated, the system further comprises means 16 for storing the electrical energy produced, such as for example a set of batteries, which are electrically connected to the generator means and are carried, for example, by the supporting structure.
An important characteristic of the system described herein consists in the fact that it comprises actuator means designed to control rotation of the first frame about the first axis, as a function of its angular position in such a way that in operation the first frame will perform, about the first axis, complete rotations through 360°, in one and the same direction of rotation.
As will be seen in what follows, the actuator means are designed to exert on the first frame a torque concordant or discordant with respect to the motion of rotation of the first frame, as a function of its angular position. In various embodiments, as in the one illustrated, the means are designed to control rotation of the first frame in such a way as to keep its velocity of rotation substantially constant, or in any case always in the same direction.
As will be seen in what follows, the actuator means may be completely mechanical actuator means or else may be a control unit provided for actuating an electric motor or else the generator means themselves, switched to an operating mode of a motor type so as to exert on the first frame a torque that is either concordant or discordant with respect to its motion of rotation, as a function of the angular position of the first frame itself.
In order to render as clear as possible to a person skilled in the art the criteria underlying operation of the actuator means, described in brief hereinafter, with reference to
In particular,
As is known to the person skilled in the branch, the gyroscopic torque is given by the following equations:
{right arrow over (T)}=I·{dot over ({right arrow over (φ)}×{dot over ({right arrow over (δ)}
T=I·({dot over (φ)}·cos ε)·{dot over (δ)}
where:
As is evident from the equations, the gyroscopic torque T depends upon the vector of the velocity of oscillation of the floating body (vector {dot over ({right arrow over (δ)}) and upon the vector of the velocity of rotation of the rotor (vector {dot over ({right arrow over (φ)}), specifically upon the component of the vector orthogonal to the vector {dot over ({right arrow over (δ)}, the component being given by {dot over (φ)}×cos ε, and thus varying, given the same modulus {dot over (φ)}, as a function of the angular position of the vector {dot over ({right arrow over (φ)}.
Represented in
a illustrates an instant at which the floating body is moving at the maximum velocity about the axis Δ, in a counterclockwise direction, and the axis has assumed a condition orthogonal to the axis Δ. In the condition, the gyroscopic torque {right arrow over (T)} is in a counterclockwise direction and assumes a maximum value in so far as the velocity of oscillation of the floating body is maximum; i.e., the modulus of the vector {dot over ({right arrow over (δ)} is maximum, and the component {dot over ({right arrow over (φ)}×cos ε is also maximum. The gyroscopic torque {right arrow over (T)} thus causes rotation of the first frame—i.e., the axis of rotation Φ about the axis E in a counterclockwise direction.
b illustrates a step in which the floating body continues to oscillate in a counterclockwise direction about the axis Δ, and the axis Φrotates about the axis E in a counterclockwise direction, pushed by the gyroscopic torque {right arrow over (T)}.
c illustrates a step in which the body 2 is close to reversal of the motion from the counterclockwise direction to the clockwise direction, and the axis of rotation Φ is almost parallel to the axis Δ. In the condition, the gyroscopic torque is substantially zero in so far as the velocity of oscillation of the floating body is almost zero—by now close to reversal of the motion—and the component {dot over (φ)}×cos ε of the vector {dot over ({right arrow over (φ)} is likewise approximately zero. Between the step of
d illustrates a step in which the floating body has only just reversed its motion of oscillation and now rotates in a clockwise direction (see in this connection the vector {dot over ({right arrow over (δ)}), whereas the axis of rotation Φ turning in a counterclockwise direction has only just exceeded the condition of parallelism with the axis Δ. As may be seen from a comparison between
Between the step of
As has been seen, in the steps illustrated above, the gyroscopic torque {right arrow over (T)} is such as to act always in the same direction. It is thus possible to envisage operation of the system in which a gyroscopic torque is generated that, within each cycle of oscillation of the floating body, will produce as a whole useful work always and only in the same direction of rotation, thus causing rotation of the first frame always and only in the direction. The modality of operation illustrated above brings with it the advantage of optimal exploitation of the sea waves; in particular, in the case where, as in the example illustrated in
In this context, the actuator means referred to above have the function of guaranteeing the mode of operation by causing the motion of rotation of the first frame to be synchronized with the motion of pitch—and/or roll—of the floating body, so that, as has been mentioned above, within each cycle of oscillation of the floating body, the induced gyroscopic torque {right arrow over (T)} will produce as a whole useful work always and only in the same direction of rotation. As will be seen in what follows, for the purpose the actuator means “expend” a part of the energy of the system to exert on the first frame torques that are concordant or discordant with respect to the motion of rotation of the first frame, the energy being, however, returned to the system—with some reduction on account of the losses due to friction—in the form of useful work by the gyroscopic torque itself.
As has been mentioned above, the means have the function of synchronizing the motion of rotation of the first frame with the motion of pitch of the floating body, so that, within each cycle of oscillation of the floating body, the induced gyroscopic torque {right arrow over (T)} will be as a whole such as to produce useful work always and only in the same direction of rotation.
In particular, the means illustrated in
As illustrated in
In the step of
In the steps of
Between the step of
As has been seen above, during rotation of the axis Φ, i.e., during rotation of the first frame, the springs act first so as to oppose the motion and then so as to sustain it. In the light of what has been illustrated with reference to
It is to be noted that the type of control can be provided also via mechanical means different from the ones illustrated in
As mentioned previously, the control referred to above can be performed also via the electric-generator means themselves.
In general, it is to be noted that the action of control exerted by the actuator means of the system on the first frame may also vary from the one described above with reference to
It is to be noted that in the examples illustrated above a system has been described that is to be used in areas of water characterized by a wave motion with a substantially constant cycle. The system is, in fact, pre-arranged for synchronizing with a single type of motion, which is a characteristic of the area in which the system will be used. As has been seen above, in the system the actions of the actuator means are set on the basis of the angular position alone of the first frame, since, as is evident to the person skilled in the art, within a sinusoidal motion with a substantially constant cycle, the position is directly correlated with the phase of the cycle of the wave motion so that by controlling the position to all effects the movement of the first frame is co-ordinated with respect to the motion. It is, however, possible to pre-arrange the system described herein also for uses in areas of water with variable wave motion. For this purpose, the system can envisage one or more acceleration sensors designed to detect the accelerations induced on the floating body by the wave motion, as likewise one or more position sensors, velocity sensors and/or torque sensors, and actuator means designed to control rotation of the first frame, not only as a function of the angular position of this, but also as a function of the signals produced by the sensors. In this way, the system may be synchronized also with variable wave motions. The criteria with which the actuator means act on the first frame remain in any case the same as the ones that have been described above.
As has been the previously, the system described herein can provide also a gyroscope structure with two degrees of freedom, comprising a first rotatable frame and a second rotatable frame. In the embodiment, by applying the same criteria as the ones highlighted above, it is possible to envisage that both of the frames, or else just one of these, will turn always and only in one and the same direction. As compared to the one previously illustrated, the embodiment affords the advantage of enabling exploitation both of the motion of pitch and of the motion of roll of the floating body.
As emerges from the above description, the system described herein envisages an operation in which the system expends energy for synchronizing with the action of the sea waves on the floating body, but by so doing is able to exploit in an optimal way the gyroscopic torques induced by the wave motion, reducing as much as possible the losses of energy due to the forces of inertia. The present applicant has in this connection found that the system described herein presents levels of operating efficiency that are higher than those obtained in systems of a known type. Moreover, as may be seen in
Of course, without prejudice to the principle of the invention, the details of construction and the embodiments may vary, even significantly, with respect to what has been illustrated herein purely by way of non-limiting example, without thereby departing from the scope of the invention, as defined by the annexed claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| TO2011A000879 | Oct 2011 | IT | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IB2012/055268 | 10/2/2012 | WO | 00 | 4/1/2014 |