WO2016027026A1

WO2016027026A1 - Facility for producing electrical energy by means of converting wave energy

Info

Publication number: WO2016027026A1
Application number: PCT/FR2015/052195
Authority: WO
Inventors: Charles DUMORTIER
Original assignee: Dumortier Charles
Priority date: 2014-08-20
Filing date: 2015-08-11
Publication date: 2016-02-25
Also published as: FR3025004B1; FR3025004A1

Abstract

The invention relates to a facility (1) for producing electrical energy by means of converting wave energy in a stretch of water, of the type comprising a flotation body (2) containing a wave energy converter comprising at least one mobile element designed so as to oscillate vertically under the effect of the vertical undulation of the waves, and a device for converting the vertical oscillation of the mobile element into electrical energy, said facility (1) being characterised in that it also comprises at least one upstream structure (3) submerged in the stretch of water and positioned upstream of the flotation body (2) in the direction of the waves, said upstream structure (2) being designed so as to regulate the frequency of vertical undulation of the waves upstream of the flotation body (2) to a resonance frequency of the wave energy converter.

Description

The present invention relates to an installation for producing electrical energy by converting wave energy in a body of water.

The invention is in the field of the production of electrical energy from the potential energy and kinetic alternative contained in the movement of vertical back and forth waves, called wave energy.

To convert this wave energy into electrical energy, it is known to employ a wave energy converter disposed inside a buoyancy body (or buoy) anchored directly to the bottom or moored to a floating structure, and comprising a mobile element oscillating vertically. The vertical oscillation of the moving element, induced by the vertical wave ripple, is converted into electrical energy.

For this purpose, there are converters of the "point absorb" type comprising, inside the buoyancy body, a movable magnet slidably guided inside the buoyancy body along a fixed axis and connected to a upper part of the buoyancy body by a return spring, and an annular coil mounted inside the buoyancy body and traversed by the fixed axis.

The operation of a "point absorbing" type converter is as follows: the waves cause a vertical movement of the floatation body, which is transmitted to the magnet via the spring, thus creating a vertical oscillation of the magnet which is converted in induced electric current in the coil.

There are also other technologies that exploit the oscillation of a vertically oscillating moving element to produce electricity.

However, it turns out that the conversion of the vertical oscillation of the mobile element into electricity is optimal for a so-called resonance oscillation frequency. Indeed, the electrical conversion is performed by means of an oscillating system which has a maximum of efficiency at a vertical oscillation frequency of the movable element corresponding to the resonance frequency. This is particularly the case with a converter of the "point absorb" type where the resonant frequency is a function in particular of the spring stiffness constant, the weight of the various constituent elements of the converter, and the shape of the buoyancy body. Thus, the Applicant has identified the importance of playing on the wave frequency so that the vertical oscillation frequency of the oscillating mobile element is closer to the resonance frequency of the converter.

The object of the present invention is to propose an installation for producing electrical energy using a converter provided with a mobile element oscillating substantially at the resonance frequency induced by the movement of the waves in order to increase the efficiency of production of electrical energy.

For this purpose, it proposes an installation for producing electrical energy by converting wave energy in a body of water, of the type comprising a buoyancy body inside which is disposed a wave energy converter comprising at least a movable member shaped to oscillate vertically under the effect of the vertical wave corrugations and a device for converting the vertical oscillation of the mobile element into electrical energy, said installation being remarkable in that it further comprises at least one Upstream structure immersed in the body of water and positioned upstream of the flotation body in the direction of the waves, said upstream structure being shaped to adjust the vertical wave-wave frequency upstream of the flotation body at a resonant frequency of the wave energy converter.

Thus, the invention proposes to regulate the vertical wave-wave frequency in a suitable frequency range so that the vertical oscillation frequency of the energy converter is closer to the resonance frequency of the converter, by the immersion of an upstream submerged structure upstream of the converter. This upstream structure increases the vertical amplitude of the waves reaching the flotation body and especially regulates their vertical ripple frequency to ensure optimal operation of the converter at the resonant frequency.

The upstream structure thus acts as a kind of amplifier of the vertical wave movement which increases the efficiency of the converter while providing an additional advantage which is to protect the converter placed downstream of the upstream structure.

In this way, the invention makes it possible to convert into electricity the amplitude of the waves corresponding to the vertical movement following the sinusoid of the waves, with an optimization in the recovery in working, thanks to the immersed upstream structure, the resonance frequency of the oscillating element. Indeed, like any oscillating system, the oscillating element has a resonance frequency.

According to one characteristic, the installation comprises an anchoring system of the upstream structure on the bottom of the body of water, this anchoring system incorporating a device for adjusting the immersion depth of the upstream structure.

With this depth adjustment device, it is possible to control the effect produced on the vertical wave frequency and the amplitude of the waves to optimize the operation of the converter at the resonance frequency.

According to another characteristic, the device for adjusting the immersion depth of the upstream structure is automatically controlled by the vertical oscillation frequency of the mobile element of the converter, in order to slave said vertical oscillation frequency around the resonance frequency of the wave energy converter.

Thus, the control of the immersion depth of the upstream structure is automated, to allow adaptation in real time to the local conditions of the waves.

In a particular embodiment, the anchoring system incorporates a device for adjusting the inclination of the upstream structure.

By acting on the inclination of the upstream structure, it is also possible to control as accurately as possible the amplitude and the vertical wave frequency of the waves necessary for operation of the converter at the resonance frequency.

Advantageously, the upstream structure has in the front part a rising ramp positioned in the direction of the waves.

This form of rising ramp for the waves arriving on the upstream structure is particularly advantageous for controlling the frequency and the amplitude of the waves.

In a particular embodiment, the upstream structure is at least partially covered with a hydrophobic film, thus making it possible to accelerate the movement of the waves on the upstream structure, which is advantageous for the operation described above.

According to a possibility of the invention, the converter is hooked on the upstream structure. According to another possibility of the invention, the mobile element of the wave energy converter comprises a magnetic member carrying a plurality of magnets and slidingly guided inside the buoyancy body along at least one fixed axis and connected to an upper part of the buoyancy body by at least one return spring, and the conversion device of the wave energy converter comprises an assembly of coils arranged in a ring and mounted on a support inside the buoyancy body, this assembly coil being traversed at its center by the fixed axis.

The invention is particularly well adapted to work with such a type of converter, called "point absorb", where the support assembly with coils - magnetic member forms a linear motor converting the oscillating movement of the magnetic member into electrical current induced in the coils distributed in a ring.

According to another characteristic of the invention, the support of the coils is either fixedly mounted inside the buoyancy body or slidably mounted on translation guides and connected to a lower part of the buoyancy body by at least one spring. recall.

In the embodiment where the coil carrier is also movable, the power supplied is improved over a fixed or static coil carrier.

In an advantageous embodiment, the buoyancy body is provided with peripheral outer fins enabling said floatation body to be rotated under the effect of the horizontal movement of the waves, and internally incorporates a system for converting the rotation of the buoyancy body into electric energy.

Thus, the installation also recovers the energy provided by the wave current, corresponding to the horizontal movement of the waves, by rotating the buoyancy body, to convert it into electrical energy.

The invention also relates to a method for producing electrical energy by converting wave energy in a body of water, of the type comprising the following steps:

positioning in the body of water at least one flotation body inside which is disposed a wave energy converter comprising at least one movable element shaped to oscillate vertically under the effect of vertical waves waves and a device for converting the vertical oscillation of the mobile element into electrical energy; and

positioning, upstream of the buoyancy body in the direction of the waves, at least one upstream structure immersed in the body of water, said upstream structure being shaped to adjust the wave vertical wave frequency upstream of the buoyancy body at a resonant frequency of the wave energy converter.

According to one possibility, this method also comprises a step of adjusting the immersion depth of the upstream structure.

According to another possibility, the adjustment of the immersion depth of the upstream structure is automatically controlled by the vertical oscillation frequency of the mobile element of the wave energy converter, so as to slave said vertical oscillation frequency around of the resonance frequency of the wave energy converter.

Other features and advantages of the present invention will appear on reading the following detailed description of several nonlimiting exemplary embodiments, with reference to the appended figures in which:

FIG. 1 is a diagrammatic perspective view of an electrical energy production installation according to the invention, in a situation in a body of water;

- Figure 2 is a schematic side view of a first flotation body adapted for an installation according to the invention;

- Figure 3 is a schematic perspective view of a second flotation body adapted for an installation according to the invention;

FIG. 4 is a schematic view of a first wave energy converter adapted for an installation according to the invention;

FIG. 5 is a schematic view of a second wave energy converter adapted for an installation according to the invention;

FIG. 6 is a schematic view of a third wave energy converter adapted for an installation according to the invention; FIG. 7 is a diagrammatic view, seen from the front and from the side, of a fourth wave energy converter adapted for an installation according to the invention;

- Figure 8 is a schematic perspective view of a first submerged upstream structure in a situation in a body of water;

- Figure 9 is a schematic perspective view of three other upstream structures.

With reference to FIG. 1, an installation 1 according to the invention essentially comprises:

a buoyancy body 2, or buoy, which internally integrates a wave energy converter adapted to convert the potential energy of the waves, generated by the vertical waves of the waves, into electrical energy; and

- An upstream structure 3 immersed in the body of water and positioned upstream of the float body in the direction of advance of the waves, shown schematically by the arrow AV.

The buoyancy body 2 is a hollow body, adapted to float, and having a symmetry of revolution about a vertical central axis. This buoyancy body 2 may have a cylindrical, conical shape or a shape with a parametric arc profile as illustrated in FIG. 2.

With reference to FIG. 3, the buoyancy body 2 may be provided with a plurality of outer peripheral fins 20 for rotating the buoyancy body 2 under the effect of the horizontal movement of the waves, in order to convert the kinetic energy. waves, generated by the horizontal movement of the waves, in electrical energy.

In a first example illustrated in FIG. 4, the wave energy converter 4, disposed inside a buoyancy body 2, comprises:

a magnetic member 40 carrying several magnets and guided in sliding inside the buoyancy body 2 along at least one fixed axis

41 and connected to an upper portion 21 of the buoyancy body 2 by at least one return spring (not shown), and

- An assembly of several coils 42 arranged in a ring and mounted on a support 43 inside the buoyancy body 2, this assembly of coils 42 being traversed at its center by the fixed axis 41. Thus, the magnetic member 40 forms a mobile element oscillating under the effect of vertical wave waves through the return spring, at an oscillation frequency corresponding substantially to the wave vertical wave frequency. Thus, the magnetic member 40 generates, with its magnets, a current induced in each coil 42 during its alternating passages through the assembly of the coils 42 distributed in a ring.

The fixed axis 41 is fixed at its two ends on respectively the upper part 21 and the lower part 22 opposite the buoyancy body 2; this fixed axis 41 extending vertically in situation on the body of water. The return spring, fixed both on the upper part 21 of the buoyancy body 2 and on the movable magnetic member 40, provides an elastic return of the magnetic member 40 towards this upper portion 21, and is advantageously constituted a tension spring.

In the embodiment of FIG. 4, the support 43 is fixed or static, and is situated substantially midway between the upper part 21 and the lower part 22 of the buoyancy body 2.

In a second example illustrated in FIG. 5, and which constitutes a variant of the first example mentioned above, the wave energy converter 4 is of the same type as described above, comprising a magnetic member 40 movable on at least one fixed axis 41. and an assembly of a plurality of corona coils 42 carried by a support 43, with one difference that this support 43 is slidably mounted on guide rods 44 which make it possible to guide the support 43 in vertical translation, and that this support 43 is connected to the lower part 22 of the buoyancy body 2 by at least one return spring (not shown).

In addition, in the first example, the magnetic member 40 slides along a single fixed axis 41, while in the second example the magnetic member 40 slides along several fixed axes 41, in this case four fixed axes. 41.

The guide rods 44, just like the fixed axes 41, are fixed at their two ends on respectively the upper part 21 and the opposite lower part 22 of the buoyancy body 2.

More specifically, the support 43 is of square shape, which makes it possible to remove the obligatory iron cores to channel the magnetic flux of the magnets in the case of the first example of FIG. 4, where the support 43 is cylindrical. In addition, this square shape advantageously makes it possible to reduce the space between the coils 42 and the magnets of the magnetic member 40.

Thus, the support 43 and therefore the coils 42 are connected to the lower part 22 of the buoyancy body 2 by at least one spring of the compression spring type, while the magnetic member 40 and therefore the magnets are connected to the upper part 21 of the buoyancy body 2 by at least one return spring of the tension spring type, thereby creating a phase opposition phenomenon in their displacements, with the advantage of increasing the electrical power generated with respect to a mode with static support 43.

In a third example illustrated in FIG. 6, the magnetic member 40 and the coil support 43 are connected together by a tension wire 45 engaged at 180 ° on a pulley 46, while the magnetic member 40 and the support 43 both are connected to the upper part 21 of the buoyancy body 2 by return springs 47.

Thus, in this third example, the magnetic member 40 and the support 43 with coils can move in phase opposition, regardless of the oscillation frequency, which makes it possible to increase the generated electric power compared to a mode with static support 43.

In the first three examples described above, the wave energy converter 4 uses a linear motor composed mainly of a support assembly 43 with coils 42 - magnetic member 40 with magnets, where the relative movement between the coils 42 and the magnets is a linear or rectilinear motion.

In a fourth example, the wave energy converter 4 uses at least one rotary motor 50 conventionally comprising a stator composed of windings or permanent magnets, and a rotor consisting of a set of coils connected to a rotary shaft 51 rotating.

The rotary shaft 51 is connected to a flywheel 52, integral in rotation with the rotary shaft 51. A gearbox 53 is optionally positioned between the flywheel 52 and the rotor of the rotary motor 50, in order to obtain a rotational speed of the rotor greater than that of the flywheel 52. As illustrated in FIG. 7, it is it is conceivable to have two sets of gearbox 53 - rotary motor 50 on either side of the flywheel 52.

The wave energy converter 4 also comprises a mass 54 connected to the upper part 21 of the buoyancy body by at least A return spring 55. Thus, this mass 54 oscillates vertically under the effect of the vertical wave waves, by means of the return spring 55. The vertical oscillation of the mass 54 is converted into a rotation of the steering wheel. inertia 52 by means of a connecting rod 56 articulated on the mass 54 and on the flywheel 52.

In the case where the buoyancy body 2 is provided with several external peripheral fins 20, this buoyancy body 2 internally integrates, in addition to the aforementioned wave energy converter 4, a system (not shown) for converting the rotation of the body. Flotation 2 in electrical energy. As such, the conversion system may comprise a rotary motor with a fixed stator consisting of windings or permanent magnets, and a rotor consisting of a coil assembly rotated by the buoyancy body 2.

The function of the upstream structure 3 is to adjust the wave vertical wave frequency upstream of the buoyancy body 2 to a resonant frequency of the wave energy converter 4. In this way, the vertically oscillating element or elements of the wave converter wave energy 4 oscillate at the resonant frequency which corresponds to the oscillation frequency offering the best efficiency of electric power production.

With reference to FIG. 8, the upstream structure 3 is anchored to the bottom F of the body of water by means of an anchoring system 6 which comprises several strands 60 attached to the upstream structure 3 and weighted on the bottom F using weights 61.

This anchoring system 6 also comprises a device for adjusting the immersion depth of the upstream structure 3, which comprises a retractor 62 for each rope 60. In this way, by winding more or less the ropes 60, it is possible to to vary the immersion depth of the upstream structure 3.

This device for adjusting the depth of immersion also forms a device for adjusting the inclination of the upstream structure 3. In fact, it suffices to play on the windings of the strands 60 between the upstream and the downstream of the structure upstream 3, to obtain the desired angle.

With reference to FIGS. 8 and 9, several forms of upstream structure 3 are conceivable, and each upstream structure 3 has, in the front part, a rising ramp positioned in the direction of the waves. ramp 30 being extended by a plate 31. The ramp 30 may have a rectilinear or curved slope, and the tray may have a rectangular, square, semicircular, semi-ellipsoidal or other shape.

Furthermore, the buoyancy body 2 is anchored or attached to the upstream structure 3, by means of a rope or rope of predetermined length, so that the buoyancy body 2 is maintained downstream of the upstream structure 3 at a distance fixed; this flotation body 2 receiving waves whose vertical ripple frequency is modified locally thanks to the upstream structure 3.

The resonance frequency depends in particular on the mass of the vertically oscillating elements of the wave energy converter 4, the stiffness of the return spring or springs, the geometric shape and the dimensions of the buoyancy body: an optimization of these parameters being advantageous for establishing a resonant frequency coherent with the local conditions of the waves.

The wave vertical wave frequency downstream of the upstream structure 3 (and therefore upstream of the buoyancy body 2) depends on the geometry and dimensions of the upstream structure 3, as well as the immersion depth of the structure. upstream 3.

Of course the examples of implementations mentioned above are not limiting and other improvements and details can be made to the installation according to the invention, without departing from the scope of the invention where others For example, the shapes of the buoyancy body and / or the upstream structure may be made.

Claims

1. Installation (1) for producing electrical energy by converting wave energy in a body of water, of the type comprising a buoyancy body (2) inside which is disposed a wave energy converter (4) comprising at least one movable element shaped to oscillate vertically under the effect of the vertical wave corrugations and a device for converting the vertical oscillation of the mobile element into electrical energy, said installation (1) being characterized in that it comprises in addition at least one upstream structure (3) immersed in the body of water and positioned upstream of the floating body (2) in the wave direction, said upstream structure (3) being shaped to adjust the ripple frequency vertical waves upstream of the floatation body (2) at a resonant frequency of the wave energy converter (4).

2. Installation (1) according to claim 1, comprising an anchoring system (6) of the upstream structure (3) on the bottom (F) of the body of water, said anchoring system (6) integrating an adjustment device (62, 60) for the immersion depth of the upstream structure (3).

3. Installation (1) according to claim 2, wherein the adjustment device (62, 60) of the immersion depth of the upstream structure (3) is controlled automatically by the vertical oscillation frequency of the movable member. of the converter, in order to slave said vertical oscillation frequency around the resonance frequency of the wave energy converter (4).

4. Installation (1) according to claims 2 or 3, wherein the anchoring system (6) incorporates a device (62, 60) for adjusting the inclination of the upstream structure (3).

5. Installation (1) according to any one of the preceding claims, wherein the upstream structure (3) has in the front part a ramp (30) rising positioned in the direction of the waves.

6. Installation (1) according to any one of the preceding claims, wherein the upstream structure (3) is at least partially covered with a hydrophobic film.

7. Installation (1) according to any one of the preceding claims, wherein the buoyancy body (2) is hooked on the upstream structure (3).

8. Installation (1) according to any one of the preceding claims, wherein the movable element of the wave energy converter (4) comprises a magnetic member (40) carrying several magnets and slidingly guided inside the body flotation device (2) along at least one fixed axis (41) and connected to an upper part (21) of the buoyancy body (2) by at least one return spring, and the conversion device of the converter wave energy (4) comprises an assembly of coils (42) arranged in a ring and mounted on a support (43) inside the buoyancy body (2), this assembly of coils (42) being traversed at its center by the fixed axis (41).

9. Installation (1) according to claim 8, wherein the support (43) of the coils (42) is either fixedly mounted inside the floating body (2) is slidably mounted on guides (44) in translation and connected to a lower part (22) of the buoyancy body (2) by at least one return spring.

10. Installation (1) according to any one of the preceding claims, wherein the buoyancy body (2) is provided with outer fins (20) peripheral allowing the rotation of said float body (2) under the effect of the horizontal movement of the waves, and integrates internally a system for converting the rotation of the buoyancy body (2) into electrical energy.

1 1. A method of producing electrical energy by converting wave energy in a body of water, of the type comprising the following steps:

- positioning in the body of water at least one flotation body (2) inside which is disposed a wave energy converter (4) comprising at least one movable member shaped to oscillate vertically under the effect of the vertical wave waves and a device for converting the vertical oscillation of the mobile element into electrical energy; and

positioning, upstream of the buoyancy body (2) in the direction of the waves, at least one upstream structure (3) immersed in the body of water, said upstream structure (3) being shaped to adjust the ripple frequency vertical waves upstream of the floatation body (2) at a resonant frequency of the wave energy converter (4).

12. The method of claim 1 1, comprising a step of adjusting the immersion depth of the upstream structure (3).

Method according to claim 12, wherein the adjustment of the immersion depth of the upstream structure (3) is automatically controlled by the vertical oscillation frequency of the moving element of the wave energy converter (4), to enslave said vertical oscillation frequency around the resonant frequency of the wave energy converter (4).