DE102010025907A1 - Wave energy converter for the conversion of kinetic energy into electrical energy - Google Patents

Abstract

The invention relates to a wave energy converter for converting kinetic energy of a wave motion of a fluid into electrical energy. The wave energy converter has a cylinder (7) which is guided in the fluid (2) in such a way that it can follow a wave motion of the fluid (2). A second body (8) is coupled to the cylinder (7), but so as to be movable with the cylinder. An energy conversion unit (16) serves to convert the kinetic energy of a relative movement between the second body (8) and the cylinder (7) into electrical energy. The energy conversion unit (16) includes a capacitor containing an electroactive polymer and whose capacity changes as the electroactive polymer is deformed. The relative movement between the second body and the cylinder causes a change in capacity.

Description

The invention relates to a wave energy converter for converting kinetic energy into electrical energy. A variety of wave energy converters are known in the art. These can be differentiated according to location, depending on whether they are located on the high seas, near the coast or on the coast. Another distinction relates to how the energy is taken from the wave motion. For example, buoys float on the water surface, so that lifting and lowering the buoyant body drives a linear generator. In another system concept, the so-called "Wave Roller", a wing is placed on the seabed, which is tilted back and forth due to the movement of the water molecules. The kinetic energy of the wing is converted in a generator, for example, into electrical energy. An overview of wave energy power plants is shown in the book "Renewable Energy" by Godfrey Boyle.

The US 7,649,276 B2 shows a wave energy generator in which the kinetic energy of a wave causes an up and down movement of a rod, which in turn drives a power conversion unit.

The systems known in the prior art have in common that they can convert only a small part of the energy present in the shaft.

It is an object of the invention to provide an energy conversion unit which has a greater efficiency than known in the prior art systems.

This object is achieved with the subject of the independent claim. Advantageous developments emerge from the subclaims.

The invention relates to a wave energy converter for converting kinetic energy of a wave motion of a fluid into another form of energy. The wave energy converter has a cylinder which is immersed in the fluid. A second body is at least partially provided within the cylinder, but so that the second body is movable to the cylinder.

In this case, the second body is approximately perpendicular to a longitudinal axis of the cylinder translationally movable relative to the cylinder. This does not exclude that the relative movement additionally has a rotation component. An energy conversion unit is designed such that, during operation, it converts an energy of the relative translatory movement between the second body and the cylinder into the other form of energy.

The relative movement between the cylinder and the second body is thus used to convert the energy of the relative movement, kinetic energy and possibly potential energy, into another form of energy. The cylindrical shape has the advantage that forces acting on the cylinder from a shaft can attack uniformly in the circumferential direction. Thus, the energy is also transmitted evenly from the shaft to the cylinder, which increases the efficiency of the wave energy plant.

Preferably, a bearing is provided between the second body and the cylinder for the relative movement between the second body and cylinder to be on predetermined paths.

In one embodiment, a part of the second body is provided stored in the cylinder and another part of the second body is protruding from the second cylinder. This allows water molecules to move the part of the second body outside the cylinder, while the cylinder remains stable in position relative to the seabed. According to one embodiment, the wave energy converter additionally comprises attenuators for damping the movement between the cylinder and the second body. Thus, the relative movement between the cylinder and the second body can be adjusted so that it gains as much energy from the wave energy, since it depends on the natural frequency of the system between the cylinder and the second body, how effective the energy conversion is.

Preferably, the attenuators are adjustable. As a result, consideration can be given to different wave frequencies.

By guiding one of the body cylinders and second bodies on a circular path or an elliptical path, the wave motion of the fluid is used as efficiently as possible for energy conversion. Underwater waves cause an orbital motion of the water molecules. By guiding on circular or elliptical paths, the energy is used throughout the duration of the orbital motion. The provision of the second body in the cylinder causes the energy conversion to take place in the cylinder or close to the cylinder, resulting in a compact design. This also avoids transmission losses, or by friction, in the transmission of the kinetic energy of the circular or elliptical movement to a remote energy conversion unit.

The energy conversion unit in one embodiment includes a capacitor containing an electroactive polymer and its capacity changes in the deformation of the electroactive polymer. The condenser is disposed between the second body and the cylinder. The relative movement between the second body and the cylinder causes a change in capacity.

With such an energy conversion device, it is possible to use the wave energy particularly efficiently. This is due to the movement of the water molecules. Water molecules, which are located below the water surface, move due to the wave motion on a so-called orbital trajectory. The following example illustrates this. At a certain location, the water level is first at a maximum, before it sinks, passes through the zero crossing, and then reaches a minimum. Then the water level rises again, goes back around the zero point, to land again at the maximum. Then the movement starts again.

When the wave is at its maximum, all water molecules below the maximum move in the propagation direction of the waves. In a right-waving wavefront to the right. During the subsequent zero crossing, the water molecules move downwards. On the other hand, they move to the left during the minimum of the wave. At the next zero crossing, the water molecules all move downwards, after which they start the described movement again from the maximum. It is understood that the water molecules move continuously in a circular motion, while here only four discrete points of this circular motion were exemplified. The diameter of this circular motion decreases with increasing water depth, so that at a water depth of one half of the wavelength almost no orbital motion is present. In shallow water, however, the water molecules no longer move on a circular path, but on elliptical paths.

The molecules of the fluid, usually water molecules, each flow radially to the cylinder so that it follows a circular path or an elliptical path. The fact that the second body is movably coupled to the cylinder, there is a relative movement between the second body and the cylinder. The provision of the capacitor with electroactive polymer has the advantage that the kinetic energy resulting from the relative movement, can be converted directly into electrical energy.

The use of electroactive polymer makes it possible to arrange capacitors so that relative movements between the cylinder and the second body of at least one of the capacitors changes its capacity, whereby energy can be obtained.

Thus, it is possible to convert energy from movement acting in different directions into electrical energy. In the classic buoy power plants, only the energy resulting from the up and down movement of the buoy is used. However, the movement of the water molecules under the water surface is a complete circular motion or elliptical motion whose energy can be continuously converted by means of the wave energy converter presented.

The advantage of continuous energy production is that it is effective because energy is being transformed throughout the movement. In addition, it has the advantage that due to the continuous generation of the energy, no peak values of the energy of the other form of energy must be smoothed, as is the case, for example, with the "Wave Roller".

The cycle for converting kinetic energy into electrical energy by means of a capacitor with an electroactive polymer from the class of dielectric elastomers can be outlined as follows. At the beginning, the polymer is relaxed and no charge is on the plates of the capacitors. Subsequently, the polymer is stretched so that the capacitor has a high capacity. Subsequently, charges are applied to the capacitor and the polymer is relaxed again. This reduces the capacitance, which leads to higher voltages while the charge remains constant. The charges are dissipated, and from the voltage difference of the charges between the charging and the discharging, electric power is obtained which can be consumed in a load. In alternative embodiments, instead of the charge, the voltage or electric field is kept constant.

In one embodiment, the second body is enclosed by the cylinder. This has the advantage that the interior of the cylinder can be separated from the water surrounding the cylinder. There is thus no risk that the energy conversion unit or, for example, a storage between the second body and cylinder will be damaged by the water.

Preferably, the energy conversion unit comprises a polymer belonging to the class of dielectric elastomers. As a rule, the capacitor is realized by a layer structure in which electrode layers alternate with elastomer layers. The electrodes are made of flexible electrically conductive material which follows the strains and compressions of the elastomer. The charging and discharging from the capacitor via flexible electrode connections, z. As cables that can follow the deformations, strains and compressions of the electroactive polymer. Here, in particular, operating states near the natural frequency are to be aimed for.

In an alternative embodiment, the energy conversion unit includes at least one hydraulic cylinder which causes a change in the pressure in a hydraulic fluid due to a relative movement between the second body and the cylinder. In addition, the energy conversion unit includes a generator for converting the energy of the hydraulic fluid into electrical energy.

In one embodiment, the second body is attached to the seabed. This ensures that the second body and cylinder make a relative movement to each other, since the cylinder moves with the fluid, while the second body can not follow this movement due to the attachment in the reference frame.

Alternatively, the second body is attached to a damper plate by means of ropes or chains, the damper plate in turn being moored to the bottom of the sea.

In a further embodiment, the second body is fastened with a slack mooring in which the chain lies partially on the seabed. In this case buoyancy bodies can determine the baptismal depth.

In one embodiment, the cylinder is attached to the seabed with at least one string or leash. This ensures that the cylinder can not swim away and is fixed relative to the seabed.

With buoyancy bodies on the cylinder this can be held in suspension, if the buoyancy of the cylinder is not sufficient to ensure this. The buoyant body also serves to preload the chains that secure the cylinder to the seafloor.

With an acceleration sensor for detecting the relative movements between the cylinder and the second body, the relative movement, even if it follows complex movement patterns, can be recorded to control the charging and discharging of the capacitor.

According to a preferred embodiment, the second body is designed as a shaft which is movable in the cylinder. The areas between cylinder and shaft are segmented in the circumferential direction. The power conversion unit includes a plurality of capacitors, each of the capacitors being provided in a segment. The segmentation of the gap between the cylinder and the shaft ensures that the capacitors are divided into the different directions of movement of the relative movement between the cylinder and the second body and can be controlled independently of one another according to their respective extension states.

Movement in a first direction of the second body relative to the cylinder causes compression of a first capacitor, wherein a second capacitor is stretched on the other side of the axis.

On the other hand, the movement in another direction is effected by squeezing one other than the first capacitor. Thus, during movement in different directions, the capacitances of different capacitors are changed, whereby at least one of the capacitors can convert energy in each case.

In one embodiment, the capacitor electrodes form ring sections. Compressing the capacitors reduces the distance and increases the area between the capacitor electrodes, increasing the capacitance.

In one embodiment, the ring sections are arranged concentrically around the cylinder axis.

In another embodiment, the capacitors each contain a plurality of stacked elastomer layers with interposed mutually connected capacitor electrodes.

In one embodiment, the capacitors are arranged such that the capacitor electrodes of the capacitor extend in the direction of those areas between the shaft and cylinder which intersect the cylinder axis transversely.

The invention will now be illustrated by means of embodiments which are illustrated with the aid of the figures. Show

1 an energy converter for converting energy of a wave motion into electrical energy;

2 to 5 the energy converter during different phases of the movement;

6 the arrangement of electroactive polymer in an energy converter;

7 another embodiment of the arrangement of electroactive polymer in an energy converter;

8th a further embodiment of the arrangement of electroactive polymer in an energy converter according to the invention;

9 another arrangement of electroactive polymer in an energy converter;

10 in a further embodiment arrangements of electroactive polymers in an energy converter according to the invention;

11 in a further embodiment, the arrangement of electroactive polymer in an energy converter according to the invention;

12 a further embodiment of an energy converter;

13 a further embodiment for the arrangement of electroactive polymer in an energy converter;

14 a further embodiment of a wave energy converter;

15 the wave energy converter after 14 in the movement;

16 a further embodiment of a wave energy converter according to the invention;

17 the wave energy converter after 16 in the movement;

18 a further embodiment of a wave energy converter according to the invention;

19 the wave energy converter after 18 in the movement;

20 another embodiment of a wave energy converter.

1 shows a first embodiment of an energy converter according to the invention for converting energy of a wave motion of a fluid into electrical energy. The energy converter 1 is in the water 2 below the water surface 230 , The energy converter 1 has a cylinder 7 up in the water 2 surfaced.

The cylinder 7 indicates at the left in the 1 illustrated end face 150 a first camp 9 and a second camp 10 and on the front side shown on the right 160 a third camp 11 and a fourth camp 12 on. The anchoring chains 4 and the buoy lines 6 are on mounting rings 19 and 20 attached. At the mounting ring 19 is the first camp 9 and the mounting ring 20 is the fourth camp 12 appropriate. The fastening rings 19 and 20 are via anchoring chains 4 with the seabed 3 connected and at the same time via buoy lines 6 with at the water surface 230 located buoyancy bodies 5 attached. In advantageous embodiments, the buoyancy bodies are located below the water surface 230 , Camps 9 and 12 are formed such that the housing 18 of the cylinder 7 in relation to the attachment rings 19 and 20 can move within a circle.

The cylinder 7 has a housing 18 on, the outer walls of the cylinder 7 contains. Camps 10 and 11 are between the case 18 of the cylinder 7 and the wave 8th intended. Thus, the wave can 8th inside the cylinder 7 within a circular area relative to the cylinder 7 move. Between the camp 9 and the camp 10 as well as between the camp 11 and the camp 12 are each waterproof partitions 15 intended. Thus, the interior of the cylinder 7 protected from water.

During a movement of the water becomes the housing of the cylinder 7 guided on a circular path or an elliptical path. The wave 8th due to storage in the two camps 10 and 11 movable relative to the housing of the cylinder 7 is, moves due to its inertia relative to the housing of the cylinder 7 , The wave 8th makes this circular motion of the cylinder 7 not with the same degree. Only due to the low friction in the bearings 10 and 11 becomes the wave 8th with the cylinder 7 slightly pulled along.

This results in a relative movement between the housing 18 of the cylinder 7 and the wave 8th ,

The cylinder 7 may be considered as a coupling body coupled to the water while the second body is from the shaft 8th is formed.

Between the outer wall of the cylinder 7 and the wave 8th are energy conversion units 16 intended. These have capacitors containing electroactive polymer, in particular from the class of dielectric elastomers. The polymer is built up in layers, with flexible capacitor electrodes between the layers. The capacitance of the capacitors changes upon deformation of the electroactive polymer. By loading and unloading these capacitors can mechanical Work, due to the relative movement between the shaft 8th and the housing 18 of the cylinder 7 is performed on the electroactive polymer, are converted into electrical energy.

In 1 is the case 18 of the cylinder 7 shown so that the central axis 180 of the cylinder 7 in undeflected state by the mounting rings 19 and 20 goes. To in 1 the time shown cuts the axis 14 centered by the shaft 8th go, the two attachment rings 19 and 20 ,

Between the case 18 and the wave 8th each page has four springs 300 and four dampers 310 intended. In addition, the feathers provide 300 and dampers 310 for that the natural frequency of the generator 1 near the wave frequency is. In one embodiment, the dampers are adjustable in order to adjust the generator to different wave frequencies.

The execution according to 1 has the advantage that the inside of the cylinder 7 waterproof can be completed. Because of the front of the cylinder 7 is closed, no water can get to the moving parts inside the cylinder, which is a good protection against seawater.

2 shows the wave energy converter 1 in a deflected state. For clarity, the springs 300 and dampers 310 not drawn. Waves cause so-called orbital motions of those water molecules that are below the water surface. If, for example, a wave moves from left to right, then all the water molecules located above one another under the wave crest are moved to the right, after which they are moved downwards. Subsequently, all water molecules are moved to the left and then up again. The water molecules thus move on an orbital path.

The cylinder 7 which is in the water is also guided by the water molecules surrounding it on such an orbital path. This movement takes place around the fastening rings 19 and 20 with which the housing of the cylinder 7 over the camps 9 and 12 connected is. In 2 is shown that the cylinder was pushed down by the surrounding water molecules, so that the bearings 9 and 12 are maximally deflected. The wave 8th is located, from the seabed 3 from the point of view, in the same place as in 1 , Thus, there is a relative movement between the shaft 8th and the housing of the cylinder 7 occurred. The capacitors in the upper part of the energy conversion unit 16 are upset.

While one of the body coupling body and second body is forced by the circular motion of the mass of water molecules on a circular path, the other moves the body to out of phase. This leads to a relative movement of the two bodies and thus to a cyclic stretching of the electroactive polymer. The wave 8th it serves as inertial mass, whereby it due to the induced by the movement of the water molecules circular motion of the cylinder 7 leads to a periodic stretching of the electroactive polymer. It is realized by a quasi-continuous energy generation, since not only upward and downward movements of the water surface, but also the lateral movement components are used.

3 shows that the cylinder 7 moved to the right, while according to 4 the cylinder 7 is pushed up and in 5 the cylinder 7 was moved to the left. Relative to the fastening rings 19 and 20 is the wave 8th in figures up to 5 fixed. In reality, the wave would be 8th due to, albeit loose, coupling with the cylinder 7 move with it. This co-movement would be done with a phase shift. Assuming a phase offset of 90 °, the shaft would be on the right while the cylinder is down. If the cylinder then moves to the left, the shaft is down.

6 shows a cross section through the cylinder 7 , From outside to inside are the case 18 , the energy conversion unit 16 and the wave 8th to see. The energy conversion unit 16 contains around the shaft 8th wound capacitors. The capacitors contain superimposed elastomeric films, between which capacitor electrodes 200 and 210 are located. The films are helical around the shaft 8th wrapped and fill the gap in essence. Shown are the capacitor electrodes 200 and 210 , Between the capacitor electrodes 200 and 210 is the electroactive polymer. On the capacitor electrode 200 For example, the higher potential and the capacitor electrodes 210 the lower potential is provided in each case.

The energy conversion unit 16 is in six circle segments 22 divided up. The circle segments are circumferentially around the shaft 8th arranged. Shown are the mental interfaces 40 that the circle segments 22 separate each other. The interfaces 40 cut the axis 180 of the cylinder 7 along and extending from outer wall to outer wall of the housing 18 of the cylinder 7 ,

For example, the wave 8th pressed to the right, so change the distances between the capacitor electrodes 200 and 210 in the right one circular segment 22 that are compressed. At the same time, the distances between the capacitor electrodes 200 and 210 in the left circle segment 22 increased. At the same time the area changes too. The distance changes causes a change in the capacitance of the capacitors in the right circle segment 22 and in the left circle segment, from which electrical energy is generated according to the cycle of mechanical energy described above. The capacitor electrodes 200 and 210 in the other district segments their capacities are also changing, albeit to a lesser extent.

7 shows a cross section through a cylinder 7 a further embodiment. Here are compared to 6 the capacitor electrodes 200 and 210 not snail-shaped around the shell 18 but run concentrically to the shaft 8th , At least one of the capacitor electrodes 200 and 210 different circle segments are electrically isolated from each other.

8th shows a further embodiment of the arrangement of the energy conversion units in a cylinder 7 , This is the cylinder 7 shown in cross section. Several stack actuators 25 . 26 . 27 . 28 and 29 are inside the cylinder 7 radially around the shaft 8th arranged. Each of the stack actuators 25 . 26 . 27 . 28 and 29 each has a plurality of stacked capacitor electrodes 200 and 210 on.

9 shows a further embodiment for the arrangement of the energy conversion units in a cylinder 7 , The sectional view of the cylinder 7 shows five rollers inside the cylinder 30 around the centered shaft 8th are arranged so that the interior 31 the roles 30 on a circular path around the central axis of the cylinder 7 lie. The roles 30 each extend from the shaft 8th to the housing 18 of the cylinder 7 and each contain capacitor electrodes 200 and 210 that snail around the interior 31 the respective role 30 rolled. There is a polymer between the capacitor electrodes. Internally 31 the role 30 is located in each case compressible gas. These are the roles 30 each closed at its two end faces. Will the wave 8th inside the cylinder 7 moving in one direction becomes one of the roles 30 compressed, so that there is a change in capacity in this, whereby electrical energy can be generated from mechanical energy.

In the figure, gaps are shown between the rollers, especially near the housing. In alternative embodiments, the roles are 30 shaped so that they also fill these spaces. In further alternative embodiments, additional rollers are provided there.

The gas in each interior 31 the roles 30 ensures that the arrangement of the five roles 30 stable among each other and the roles 30 each retain their elliptical shape.

Characterized in that n = 5 rollers are provided per se, a segmentation of the energy conversion unit is given. An advantage of this arrangement is that large strokes, ie large changes in distance between shaft 8th and housing 18 , are possible because the roles 30 each be well deformed. The gas inside 31 the roles 30 ensures that the electroactive polymer in the rollers 30 is mechanically biased.

10 shows a further embodiment of the arrangement of energy conversion units in a cylinder 7 , Again, the interior of the cylinder has five rollers 30 on whose inside 31 each filled with gas. In contrast to 9 are the plates of the capacitors 200 and 210 not snail-shaped around the interior 31 arranged, but run concentrically.

11 shows a further embodiment of the arrangement of the energy conversion unit in the interior of the cylinder 7 , The housing of the cylinder consists of two cylinder halves, which are fastened together by means of a screw connection. Inside the case half 180 is the wave in their midst 80 provided while inside the case half 181 the wave 81 are housed. Between the waves 80 and 81 and the housing 18 n = 8 segments are arranged, each with circular sections 22 form.

On the right side of the 11 is a longitudinal section through the cylinder 7 according to one embodiment. Between the waves 80 and 81 and the housing 18 are each membranes 220 made of polymer, between the capacitor electrodes 200 and 210 run. The capacitor electrodes 200 and 210 however, do not run in a circle around the shaft 8th but extend only over a segment 22 ,

By movement of the shaft 8th upwards, the polymer is in the lower region, and thus also the lower capacitor electrodes 200 and 210 , stretched and the polymer in the upper area, and thus also the upper capacitor electrodes 200 and 210 , each upset.

Due to the fact that the housing halves 180 and 181 are pressed against each other, are also the waves 80 and 81 pressed on each other. This results in a bias of the membranes, which are now approximately at an angle.

12 shows a further embodiment of a wave energy converter 1 , It contains in comparison to 1 the energy conversion unit is not an electroactive polymer but hydraulic cylinder 400 caused by relative movements of the shaft 8th to the cylinder 7 compressed or compressed. Thus, the pressure of a hydraulic fluid is increased, which flows into a generator, which degrades this pressure to recover electrical energy.

13 shows that too 8th corresponding longitudinal section. In the upper part of the 13 is the longitudinal section shown at the time in which the axis is centered to the housing 18 lies. Between wave 8th and housing 18 are each stack actuators 50 intended. These each contain capacitor electrodes 200 and 210 ,

13 shows in the lower part in cross section the cylinder 7 when the case 18 in terms of the wave 8th has moved down. The stack actuators 50 in the upper part of the cylinder 7 are thus compressed in the vertical direction and stretched in the horizontal direction In contrast, the stack actuators are in the lower part of the cylinder 7 stretched in the vertical direction and compressed in the horizontal direction. The capacity of stack actuators above the shaft 8th has thus increased while the capacity of the stack actuators 50 below the shaft 8th has decreased. Between the stack actuators 50 there are free spaces 51 indicating the transverse strain of the stack actuators 50 be able to record. The provision of open spaces 51 can also in the embodiments according to the 6 . 7 . 8th and 11 make sense.

14 shows a further embodiment of a wave energy converter 1 , Compared to 1 contains the cylinder 7 only two camps 9 and 11 , This bearing connects the shaft 8th with the housing 18 of the cylinder 7 , The cylinder 7 is on its top with buoyant bodies 5 connected. In addition, the cylinder is each with chains 4 and 6 with the seabed 3 connected. The chain 4 is provided in a form of slack mooring. It is attached with one end to the seabed and is partially on the seabed. When moving the cylinder 7 on a circular path in the water shortens and lengthens the length of the part of the chain, which rests on the seabed. The wave 8th is due to the storage in the cylinder 7 movable. Because of its inertia makes the wave 8th the circular motion of the cylinder is only delayed with. This creates a relative movement between the shaft 8th and the housing 18 ,

Between cylinders 7 and wave 8th Springs and damping element can be provided with which the natural frequency of the system cylinder-shaft can be adjusted.

15 shows the wave energy converter 1 out 14 after the cylinder has moved down. The axis of the shaft 8th is located above the center axis 180 of the cylinder 7 ,

16 shows a further embodiment of a wave energy converter according to the invention 1 , This one has a cylinder 100 with a housing 18 on. The housing 18 of the cylinder 100 is via anchoring chains 4 with the seabed 3 and over buoy lines 6 with buoyancy bodies 5 connected. The cylinder 100 thus essentially remains with respect to the seabed 3 stationary. If the cylinder 100 have a neutral or slightly positive buoyancy, no buoyancy 5 needed.

Inside the cylinder 100 a coupling body is provided, which is a first shaft 90 , a second wave 91 and a third wave 92 contains. The first wave 90 is on its right side over a pole 94 stuck with the third wave 92 connected while on the left side the first wave 90 over another pole 95 with the second wave 91 is firmly connected. The waves 91 and 92 should have as neutral a lift as possible.

The wave 90 is inside the cylinder 100 while the waves 91 and 92 outside the cylinder 100 are provided. By the movement of the water, the waves become 91 and 92 brought into circular movements. Thus, the wave moves 90 with the waves 91 and 92 With. camp 9 and 11 make sure the movement of the shaft 90 inside the cylinder 100 controlled. Between the wave 8th and the housing 18 are the energy conversion units 16 are provided, each containing electroactive polymer and arranged according to one of the various above-mentioned configurations.

By the relative movement of the coupling body with the cylinder 7 For example, the capacitances of the capacitors in the polymer are changed, thereby obtaining electrical energy according to the above-mentioned cycle.

In an alternative embodiment, there are no bearings 9 and 10 provided and the coupling between cylinder 100 and the coupling body via the capacitor.

17 shows the wave energy converter 1 out 16 in a deflected position.

18 shows a further embodiment of a wave energy converter according to the invention 1 , The wave 90 of the wave energy converter 1 is directly with the fastening rings 19 and 20 connected. The fastening rings 19 and 20 are with chains 6 with the buoyancy bodies 5 and at the same time over the chains 4 connected to the seabed. The wave 90 is also over stock 9 and 11 in the case 18 of the cylinder 100 stored. The cylinder 100 thus performs circular movements in the water 2 while the wave 90 in relation to the seabed 3 essentially remains stationary. Thus, there is a relative movement between cylinders 100 and the wave 90 , The polymer in the energy conversion unit 16 and the capacitors provided in the polymer are stretched and compressed, whereby the respective capacitances of the capacitors change. The change in capacitance is utilized by means of the above-described drive of the capacitors to generate electrical energy.

Also regarding 18 is there an alternative embodiment without bearings 9 and 10 , where the coupling between cylinder 100 and the coupling body via the capacitor.

In addition, in the embodiments shown, parallel to the bearings 9 . 10 . 11 respectively. 12 In addition, springs and / or attenuators are provided. With these springs and attenuators, which can also be adjustable, the natural frequency of the system cylinder damping wave is tuned to the frequency of the wave motion. It is beneficial if the shaft is inside the case 18 is arranged so that the relative movement between the shaft and housing can be adjusted to the frequency of the wave motion.

19 one shows the energy conversion unit 18 in a deflected position. The cylinder 18 is moved up while the shaft is up 90 is stationary with respect to the seabed.

20 shows a further embodiment of an energy converter 1 , It is compared to 8th the capacitor is provided so that it is between the housing 8th and a partition 510 concentric about the center axis of the cylinder 7 runs in the interior, is provided. The wave 8th runs along this partition 510 and pushes them at the point of attack 520 between wave 8th and partition 510 in the direction of the cylinder housing 18 ,

This will also make the capacitor in the segment 22 compressed between point and cylinder housing.

LIST OF REFERENCE NUMBERS

1

Wave energy converter

2

water

3

Seabed

4

anchor chains

5

buoyancy

6

buoy lines

7

cylinder

8th

wave

9

first camp

10

second camp

11

third camp

12

fourth camp

14

shaft axis

15

partition wall

16

Energy conversion unit or electroactive polymer

18

Cylinder shell or housing

19

fixing ring

20

fixing ring

22

segment

25

stack actuator

26

stack actuator

27

stack actuator

28

stack actuator

29

stack actuator

30

role

31

Interior

50

stack actuator

51

gap

80

wave

81

wave

90

wave

91

wave

92

wave

94

pole

95

pole

150

front

160

front

180

axis

200

capacitor electrode

210

capacitor electrode

230

water surface

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 7649276 B2 [0002]

Claims (18)

Wave energy converter ( 1 ) for the conversion of kinetic energy of a wave motion of a fluid ( 2 ) into another form of energy, with the following characteristics: - a cylinder ( 7 ), which in the fluid ( 2 ) is immersed, a second body ( 8th ), at least partially within the cylinder ( 7 ), wherein the second body ( 8th ) approximately perpendicular to a longitudinal axis of the cylinder ( 7 ) translationally relative to the cylinder ( 8th ), and - an energy conversion unit ( 16 ) which is designed such that, during operation, it generates an energy of the translatory relative movement between the second body ( 8th ) and the cylinder ( 7 ) into the other form of energy. Wave energy converter according to claim 1, characterized in that a bearing ( 10 . 11 ) between the second body ( 8th ) and the cylinder ( 7 ) is provided. Wave energy converter according to claim 1 or 2, characterized in that the second body ( 8th ) of the cylinder ( 7 ) is included. Wave energy converter according to one of claims 1 to 3, characterized in that a first part ( 90 ) of the second body ( 8th ) in the cylinder ( 100 ) and that, a second part ( 91 . 92 ) of the second body from the cylinder ( 100 ) protrudes. Wave energy converter according to one of claims 1 to 4, characterized in that an attenuator and / or a spring between the cylinder ( 7 ) and the second body ( 8th ) is provided. Wave energy converter according to claim 5, characterized in that the damping member is adjustable and / or the spring stiffness is adjustable. Wave energy converter according to one of claims 1 to 6, characterized in that at least one acceleration sensor for detecting the relative movement between the cylinder ( 7 ) and the second body ( 8th ) is provided. Wave energy converter according to one of claims 1 to 7, characterized in that the energy conversion unit ( 16 ) has at least one capacitor which contains an electroactive polymer and whose capacity changes upon deformation of the electroactive polymer, and which is arranged so that the relative movement between the second body ( 8th ) and the cylinder ( 7 ) causes a deformation of the capacitor. Wave energy converter according to claim 8, characterized in that the electroactive polymer is from the class of dielectric elastomers. Wave energy converter according to one of claims 8 or 9, characterized in that the energy conversion unit ( 16 ) Has segments which are arranged circumferentially about the center axis of the cylinder, and that the energy conversion unit ( 16 ) several electrically isolated capacitors ( 25 . 26 . 27 . 28 . 29 ), each of the capacitors being provided in each of the segments. Wave energy converter according to one of claims 8 to 10, characterized in that the capacitors have capacitor electrodes which form ring sections. Wave energy converter according to claim 11, characterized in that the ring sections are arranged concentrically extending around the cylinder axis. Wave energy converter according to one of claims 8 to 12, characterized in that the capacitors each contain a plurality of stacked polymer layers and capacitor electrode layers. Wave energy converter according to one of claims 1 to 7, characterized in that the energy conversion unit ( 16 ) a hydraulic cylinder ( 400 ) due to the relative movement between the second body ( 8th ) and the cylinder ( 7 ) causes a pressure change in a hydraulic fluid. Wave energy converter according to claim 14, characterized in that a generator for converting, the energy of the hydraulic fluid is provided in electrical energy. Wave energy converter according to one of claims 1 to 14, characterized in that the cylinder ( 7 ) and / or the second body ( 8th ) is connected to the seabed by a holding device. Wave energy converter according to claim 15, characterized in that the holding device is a chain ( 4 ) or a leash, in particular the chain ( 4 ) partially rests on the seabed. Wave energy converter according to claim 15 or 16, characterized in that the holding device buoyancy body ( 5 ), which are connected to the cylinder ( 7 ) and / or to the second body ( 8th ) are coupled.

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