WO2025012387A1

WO2025012387A1 - Wave energy converter

Info

Publication number: WO2025012387A1
Application number: PCT/EP2024/069692
Authority: WO
Inventors: Sokolj VULJAJ
Original assignee: Individual
Current assignee: Individual
Priority date: 2023-07-11
Filing date: 2024-07-11
Publication date: 2025-01-16
Anticipated expiration: 2026-01-11
Also published as: EP4532922A1; AU2024288459A1

Abstract

A wave energy converter for converting kinetic energy of waves into electric energy is provided. The wave energy converter includes a base configured for being submerged on a seabed (23), a first floating weight (3), a first lever (6) connected to the floating weight (3) and the base, a first hydraulic cylinder (4) and a first piston (21) slidably received within the hydraulic cylinder (4), one of the first hydraulic cylinder (4) and the first piston (21) being connected to the base, the other one being connected to the first lever (6) or the first floating weight (3), a first output non-return valve (15) connected to an output of the first hydraulic cylinder (4), a first input non-return valve (14) connected to an input of the first hydraulic cylinder (4), a high-pressure hydraulic line (16) connected to the first output non-return valve (15), a low-pressure hydraulic line (17) connected to the first input non-return valve (14), a hydraulic tank (18) connected to the low-pressure hydraulic line (17), and a hydraulic motor (5) or turbine coupled to an electric generator, wherein an inlet (27) of the hydraulic motor (5) or the turbine is coupled to the high-pressure hydraulic line (16) and preferably an outlet (28) of the hydraulic motor (5) or the turbine is coupled to the tank (18).

Description

Wave Energy Converter

Field of the invention

The present invention relates to an energy converter. More particularly, the present invention relates to a wave energy converter for converting kinetic energy of waves into electric energy. The present invention further relates to a wave energy converter system including a plurality of such wave energy converters.

Background of the invention

Energy demand and in particular electric energy demand is increasing. At the same time, an ecofriendly way of producing electric energy becomes more and more important.

Wave energy converters offer an ecofriendly way of producing electric energy. Wave energy converters convert kinetic energy of waves into electric energy. Wave energy converters are known, for example, from documents CN 104329 212 A, WO 2014/056049 Al or WO 2006/079812 Al.

It is an object of the present invention to propose an improved wave energy converter. It is further an object of the present invention to propose a wave energy converter system including a plurality of such wave energy converters.

Solution to the problem

These and other objects, which become apparent upon reading the description, are solved by the subject-matter of the independent claims. Further embodiments and developments are provided in the dependent claims.

According to a first aspect of the present invention, a wave energy converter for converting kinetic energy of waves (also referred to as wave energy) into electric energy is disclosed. The wave energy converter comprises: a base configured for being placed on a seabed, preferably wherein the base comprises a base element and a mounting body; a first floating weight configured for floating, preferably on a water surface, and following a movement of water, preferably of the water surface, caused by waves; a first lever having a first end connected to the first floating weight and a second end connected to the base, wherein the first lever is pivotally connected to the base such that an ascending and/or descending movement of the first floating weight causes the first lever to pivotally move with respect to the base; a first hydraulic cylinder and a first piston slidably received within the first hydraulic cylinder, one of said first hydraulic cylinder and said first piston being connected such as pivotally connected to the base and the other one of said first hydraulic cylinder and said first piston being connected such as pivotally connected to the first lever or the first floating weight, preferably wherein a descending movement of the first floating weight causes the first piston to move deeper into the first hydraulic cylinder thereby compressing hydraulic fluid provided within the first hydraulic cylinder, and an ascending movement of the first floating weight causes the first piston to move further out of the first hydraulic cylinder thereby drawing hydraulic fluid into the first hydraulic cylinder; a first output non-return valve connected to an output of the first hydraulic cylinder, the first output non-return valve being configured for allowing a flow of compressed hydraulic fluid out of the first hydraulic cylinder and blocking a flow of hydraulic fluid into the first hydraulic cylinder; a first input non-return valve connected to an input of the first hydraulic cylinder, the first input non-return valve being configured for allowing hydraulic fluid to be drawn into the first hydraulic cylinder and blocking a flow of hydraulic fluid out of the first hydraulic cylinder; a high-pressure hydraulic line connected to the first output non-return valve; a low-pressure hydraulic line connected to the first input non-return valve; a hydraulic tank connected to the low-pressure hydraulic line; and a hydraulic motor or turbine coupled to an electric generator for producing electric energy, wherein an inlet of the hydraulic motor or turbine is coupled to the high-pressure hydraulic line such that compressed hydraulic fluid is provided to the hydraulic motor or turbine for turning the hydraulic motor or turbine and producing electric energy by the electric generator, preferably wherein an outlet of the hydraulic motor or the turbine is coupled to the hydraulic tank for discharging hydraulic fluid into the hydraulic tank.

The wave energy converter according to the first aspect is based at least partially on the idea that kinetic energy of ascend and/or descending waves can be converted into electric energy. The wave energy converter is based on the idea that the movement of floating weights which follows the movements of the waves can be used to move a piston within a hydraulic cylinder. Hydraulic fluid such as oil contained inside the hydraulic cylinder gets compressed by the movement of the piston and is discharged from an output of the hydraulic cylinder into a high-pressure hydraulic line via an output non-return valve.

The pressurized hydraulic fluid is transferred to a hydraulic motor or turbine which is connected to an electric generator. The pressurized hydraulic fluid drives the hydraulic motor or turbine such that electric energy is generated by the electric generator. The hydraulic fluid may then be discharged from the hydraulic motor or turbine and transferred into a tank that is connected via a low-pressure hydraulic line to an input non-return valve of the hydraulic cylinder.

The proposed wave energy converter is efficient and can be used for the production of electricity everywhere around the world where there is access to the sea (or another body of water with waves). The wave energy converter may serve as an engine for city water supply pumps, for sewage drainage pumps, for supplying salt pans with sea water, etc. The wave energy converter may be installed in the sea, for example close to the coast or where the water is not too deep because the space from the bottom to the surface of the water can be used.

The proposed wave energy converter may be fully submerged into the sea except for the floating weights, which may be floating on the water surface.

The proposed wave energy converter may be compact. A plurality of such wave energy converters may work together such as in a wave energy converter system. The wave energy converter provides an ecofriendly way of producing electric energy

Preferably, the base, and/or the base element and/or the mounting body of the base are configured to be submerged. Preferably, the mounting body is connected to a top of the base element.

Preferably, the second end of the first lever is connected to the mounting body of the base.

Preferably, the wave energy converter comprises a second floating weight configured for floating, preferably on the water surface, and following a movement of the water, preferably of the water surface, caused by waves; a second lever having a first end connected to the second floating weight and a second end connected to the base, preferably to the mounting body, and/or on a side opposite the first lever, wherein the second lever is pivotally connected to the base, preferably to the mounting body, such that an ascending and/or descending movement of the second floating weight causes the second lever to pivot with respect to the base, preferably to the mounting body; a second hydraulic cylinder and a second piston slidably received within the second hydraulic cylinder, one of said second hydraulic cylinder and said second piston being pivotally connected to the base, preferably to the base element and/or on a side opposite the side where the first hydraulic cylinder or the first piston is connected to the base, and the other one of said second hydraulic cylinder and said second piston being pivotally connected to the second lever or the first floating weight, preferably wherein a descending movement of the second floating weight causes the second piston to move deeper into the second hydraulic cylinder thereby compressing hydraulic fluid provided within the second hydraulic cylinder, and an ascending movement of the second floating weight causes the second piston to move further out of the second hydraulic cylinder thereby drawing hydraulic fluid into the second hydraulic cylinder; a second output non-return valve connected to an output of the second hydraulic cylinder, the second output non-return valve being configured for allowing a flow of compressed hydraulic fluid out of the second hydraulic cylinder and blocking a flow of hydraulic fluid into the second hydraulic cylinder; a second input non-return valve connected to an input of the second hydraulic cylinder, the second input nonreturn valve being configured for allowing hydraulic fluid to be drawn into the second hydraulic cylinder and blocking a flow of hydraulic fluid out of the second hydraulic cylinder, wherein the high-pressure hydraulic line is connected to the second output non-return valve, and the low-pressure hydraulic line is connected to the second input non-return valve.

In other words, the wave energy converter may include two floating weights, preferably arranged on opposite sides of the base. The wave energy converter may include two levers, each of the two levers is connected to a respective floating weight and the base, preferably on opposite sides of the base. The wave energy converter may include two hydraulic cylinders, wherein in each of the two hydraulic cylinders a piston is slidably received. A combination of hydraulic cylinder and piston is associated with each floating weight such that an upward movement and/or downward movement of the floating weight causes a movement of the respective piston within the respective hydraulic cylinder. Each hydraulic cylinder includes an input non-return valve and an output non-return valve connected to an input and output of the hydraulic cylinder respectively. The high-pressure hydraulic line is connected to the output of each of the hydraulic cylinders for transferring compressed hydraulic fluid to the input of the hydraulic motor or turbine for driving the same for generating electric energy.

The skilled reader will understand that the wave energy converter may include any suitable number of floating weights, such as one, two, three, four or more floating weights, and/or a corresponding number of combinations of hydraulic cylinders, pistons, input non-return valves, and output non-return valves for driving the hydraulic motor or turbine.

Preferably, the mounting body of the base is configured for mounting the hydraulic motor thereon or therein, preferably wherein the hydraulic motor is configured to be submerged under the water surface. Preferably, the mounting body is configured for mounting the hydraulic tank thereon or therein, preferably wherein the hydraulic tank is configured to be submerged under the water surface. In other words, the mounting body may be configured to include the hydraulic motor and/or the tank and at least one or both of the tank and/or the hydraulic motor may be configured to be submerged under the water surface.

Preferably the wave energy converter comprises a first upper stopper for stopping and/or limiting an upward pivot movement of the first lever and/or the first floating weight; and/or a first lower stopper for stopping and/or limiting a downward pivot movement of the first lever and/or the first floating weight. Alternatively or additionally, a second upper stopper for stopping and/or limiting an upward pivot movement of the second lever and/or the second floating weight may be provided. Alternatively or additionally, a second lower stopper for stopping and/or limiting a downward pivot movement of the second lever and/or the second floating weight may be provided. Preferably, the first upper stopper and/or the first lower stopper and/or the second upper stopper and/or the second lower stopper is configured to be submerged under the water surface.

In other words, each of the floating weights and/or lever may be associated with a respective upper and/or lower stopper for limiting an upward and/or downward movement of the respective lever and/or floating weight. If more than two floating weights and/or levers are used, the wave energy converter may comprise a corresponding number of upper and/or lower stoppers.

Preferably, the first and/or second upper stopper and/or the first and/or second lower lever stopper is arranged on the mounting body.

Preferably, the wave energy converter comprises a cooler configured for cooling the hydraulic fluid, preferably wherein the cooler is configured to be submerged.

Preferably, the cooler is arranged on the base, preferably on the mounting body.

Preferably, the cooler includes fins, preferably wherein the fins are arranged on a wall of the hydraulic tank, preferably wherein a wall of the hydraulic tank is a wall of the mounting body. In other words, the fins may be part of the mounting body. In yet other words, the mounting body may be adapted to provide for a cooler and/or fins of the cooler. The mounting body and with that the cooler and/or fins of the cooler may be submerged under the water surface.

Preferably, the wave energy converter comprises a high-pressure stabilizer for stabilizing a hydraulic pressure of the hydraulic fluid within the high-pressure line.

Preferably, the high-pressure stabilizer is arranged inside the base, preferably inside the mounting body.

Preferably, the high-pressure stabilizer includes a hydraulic fluid reservoir, preferably wherein the hydraulic fluid reservoir is formed by a space inside the base, preferably inside the mounting body.

Preferably, the high-pressure stabilizer includes a valve connecting the hydraulic fluid reservoir with the high-pressure hydraulic line, preferably wherein the valve includes a spring-loaded piston abutting on a valve seat, wherein the spring-loaded piston lifts off from the valve seat during build-up of the hydraulic pressure within the high-pressure hydraulic line such that the hydraulic fluid reservoir is filled with hydraulic fluid.

Preferably, the spring-loaded piston lifts-off or contacts the valve seat depending on an actual hydraulic pressure within the high-pressure hydraulic line such that a substantially constant hydraulic pressure within the high-pressure hydraulic line is maintained.

The high-pressure stabilizer may be used to stabilize the hydraulic pressure, e.g. when several pistons are in a charging phase and/or move deeper into the respective cylinder and/or pressurize the hydraulic fluid at the same time. Preferably, the high-pressure stabilizer may be adjustable, for example, by pre-loading the high-pressure stabilizer, for example by pumping air at several bars into the stabilizer.

Preferably, more than one high-pressure stabilizer may be used. Preferably, a spring of the spring-loaded piston may be adjustable, and/or a strength of a respective spring of a respective high-pressure stabilizer may vary. For example, a first high-pressure stabilizer may include a spring that is adjusted such that a respective hydraulic cylinders starts filling at about 100 bar and stops filling at about 150 bar, a second high- pressure stabilizer may include a spring that is adjusted such that the respective hydraulic cylinders starts filling at about 150 bar and stops filling at about 200 bar, a third high-pressure stabilizer may include a spring that is adjusted such that a respective hydraulic cylinders starts filling at about 200 bar and stops filling at about 250 bar, and so on. The stabilizer may mitigate the pressure drop and pressure rise during operation of the wave energy converter.

Preferably, the wave energy converter comprises a high-pressure safety valve configured for limiting hydraulic pressure within the high-pressure line to a predetermined upper limit.

Preferably, the high-pressure safety valve is arranged upstream of the inlet of the hydraulic motor or turbine and/or provides a by-pass for by-passing the hydraulic motor or turbine when the hydraulic pressure within the high-pressure hydraulic line approaches or exceeds the predetermined upper limit.

Preferably, the high-pressure safety valve and preferably the by-pass are arranged inside or on the base, preferably inside or on the mounting body.

Preferably, the wave energy converter comprises a low-pressure safety switch configured for switching off the hydraulic motor or turbine when the hydraulic pressure within the high-pressure hydraulic line approaches a predetermined lower limit or is below a predetermined lower limit. In other words, the low-pressure safety switch may be configured to switch off the hydraulic motor or turbine when the waves decrease and the hydraulic pressure drops.

Preferably, the base, and more preferably the mounting body, includes a first shaft and a first bearing for pivotally mounting the first lever to the base, and more preferably to the mounting body. Preferably, the base, and more preferably the mounting body, includes a second shaft and a second bearing for pivotally mounting the second lever to the base, and more preferably to the mounting body.

Preferably, the first and/or second floating weight has an annular and/or tubular shape with an open space and/or a middle opening.

Preferably, the annular and/or tubular shape is filled with material for adjusting the weight of the floating weight. Preferably, a floating weight such as the first and/or second floating weight has a weight of at least 500 kg, preferably at least 1,000 kg, more preferably at least 2,500 kg, such as about 2,500 kg.

Preferably, a hydraulic cylinder such as the first and/or second hydraulic cylinder has a volume of at least 1,000 ml, preferably at least 2,000 ml, such as about 2,209 ml, and/or a volume of 6,000 ml or less, preferably 4,000 ml or less.

Preferably, a lever such as the first and/or second lever has a length of at least 1 m, preferably at least 2 m, such as about 3 m, and/or a length of 6 m or less, preferably 5 m or less.

Preferably, the hydraulic motor has a hydraulic motor volume of at least 10 ml, preferably at least 15 ml or at least 20 ml, such as about 22.7 ml, and/or a hydraulic motor volume of 70 ml or less, preferably 40 ml or less. Preferably, the hydraulic motor has a maximum power of at least 25 kW, preferably at least 40 kW, such as 51kW, and/or a maximum power of 100 kW or less, preferably 80 kW or less.

Preferably, the base and more preferably the base element of the base includes one or more fastening sections for fastening at least one further wave energy converter to the base. In other words, a plurality of wave energy converters may be connected to one another, e.g. by fastening arranged on the base.

Preferably, the one or more fastening sections are provided on lateral sides of the base, more preferably on lateral sides of the base element.

Preferably, a first fastening section is provided on a first side of the base, more preferably of the base element, and a second fastening section is provided on a second side of the base, more preferably of the base element, that is opposite said first side.

Preferably, the wave energy converter is configured to fasten the further wave energy converter via both the first fastening section and the second fastening section (13).

Preferably, the base, more preferably the base element, includes adjustable legs for adjusting the position of the base on a terrain of the seabed.

According to a second aspect of the present invention a wave energy converter system is proposed. The wave energy converter system comprises a first wave energy converter according to the first aspect and/or embodiments thereof; and at least one second wave energy converter according to the first aspect and/or embodiments thereof, wherein the high-pressure hydraulic lines of the wave energy converters are connected to one another, and the low-pressure hydraulic lines of the wave energy converters are connected to one another.

Preferably, in the wave energy converter system, each wave energy converter may comprise a low-pressure safety switch, such as the low-pressure safety switch explained in connection with the first aspect, wherein the low-pressure safety switch may be configured for switching off the hydraulic motor or turbine of the respective wave energy converter, when the hydraulic pressure approaches a predetermined lower limit or is below a predetermined lower limit.

Preferably, the predetermined lower limit is set independently for each wave energy converter. For example, if the hydraulic pressure drops, a first wave energy converter may be switched off while the other wave energy converters of the wave energy converter system may still be working. If the hydraulic pressure drops further, a second wave energy converter may be switched off, while the remaining other waver energy converters may still be working. This shut-off procedure may continue until one or no wave energy converter is still working. The predetermined lower limit for each wave energy converter may be set independently. For example, a first wave energy converter in a system of, for example, ten wave energy converters may be switched off when the pressure approaches or drops below, e.g., 230 bar and may be switched on when the pressure approaches or exceeds, e.g., 260 bar. A second wave energy converter of the system may be switched off when the pressure approaches or drops below, e.g., 220 bar and may be switched on when the pressure approaches or exceeds, e.g., 250 bar. The pressure limits may continue in this way within the system of wave energy converters. A shut off sequence may be provided for shutting off each of the wave energy converters depending on the respective pressure limit. Multiple commands or a single command for executing the shut-off sequence may be provided. The skilled reader will understand that the pressure limits and/or the number of wave energy converters within the system are only examples, and many other suitable examples are possible. Thus, the examples provided shall not limit the scope of this disclosure.

Preferably, the wave energy converters are fastened to one another, such as chain fastened to one another, using fastening sections, such as the fastening section explained in connection with the first aspect, and/or arranged on each base of each wave energy converter.

Preferably, a number of wave energy converters used in the wave energy converter system is 2, more preferably at least 5, even more preferably 10, even more preferably at least 10 such as 12 or more.

Brief description of the drawings

Figure 1 is a schematic view of one example of a wave energy converter according to the present invention.

Figure 2 is schematic view of one example of a wave energy converter system according to the present invention.

Detailed description

Within the figures, same components are referenced by the same reference numerals. The figures are schematic and merely exemplary. They are intended to providing a thorough understanding of the present invention but shall not limit the scope of the claims.

Figure 1 shows a schematic view of a wave energy converter. The wave energy converter includes a base. The base is configured to be submerged under the water 24 and may be placed on a seabed. Adjustable legs 22 are provided for adjusting the position of the base on a terrain of the seabed. The base includes a base element 1 and a mounting body 2. The mounting body 2 is connected to a top of the base element 1 using bolts 11. The mounting body 2 may be made from stainless steel. The base element 1 may be made from concrete.

The wave energy converter includes floating weights 3. In the specific embodiment shown, the wave energy converter includes two floating weights 3. In other embodiments not shown, the wave energy converter may include a different number of floating weights 3. The floating weights 3 may be configured for floating on the water surface. The floating weights 3 follow a movement of the waves and/or of the water surface. For example, if waves of the water 24 cause the water surface to ascend or descend, the floating weights 3 ascend or descend accordingly.

In the specific embodiment shown, the floating weights 3 have an annular and/or tubular shape with an open space and/or a middle opening 26. The annular and/or tubular shape may be filled with material for adjusting the weight of the floating weights 3. For example, the floating weights 3 may have a weight of at least 500 kg, preferably at least 1,000 kg, more preferably at least 2,5000 kg, such as about 2,500 kg. Any suitable weight for the floating weights 3 is possible.

In the specific embodiment shown, the two floating weights 3 are arranged on opposite sides of the base element 1 and/or the mounting body 2. Each floating weight 3 is connected to the base by a lever 6. A first end of each lever 6 is connected to the respective floating weight 3, for example using a carrier 25. A second end of each lever 6 is pivotally connected to the base. In the specific embodiment shown, the second end of each lever 6 is pivotally connected to the mounting body 2. The mounting body 2 includes a shaft 29 and a bearing 7 on each side such that each lever 6 can be pivotally connecting to the mounting body 2. In other embodiments not shown, levers 6 may be pivotally connected to the base element 1 instead of the mounting body 2. An ascending and/or descending movement of the floating weights 3 causes the levers 6 to pivotally move upwards and/or downwards relative to the base.

For each floating weight 3 a set of hydraulic cylinder 4 and piston 21 is provided. The piston 21 is slidably received within the hydraulic cylinder 4. In the specific embodiment shown, the hydraulic cylinder 4 is connected to the base, more specifically to the base element 1, e.g., by a mount 12 and the piston 21 is connected, e.g. with a piston lever 30 to the lever 6, e.g., by another mount 12. The hydraulic cylinders 4 and pistons 21 are arranged on opposite sides of the base or base element 1 such that on a first side of the base a first hydraulic cylinder 4 with a first piston 21 is connected to a first lever 6 and therewith to a first floating weight 3, and on a second side opposite the first side a second hydraulic cylinder 4 with a second piston 21 is connected to a second lever 6 and therewith to a second floating weight 3.

The hydraulic cylinders 4 are configured to receive and/or discharge hydraulic fluid. Each hydraulic cylinder 4 includes an output with an output non-return valve 15 and an input with an input nonreturn valve 14. The output non-return valve 15 is configured for allowing a flow of compressed hydraulic fluid out of the hydraulic cylinder 4 and is configured for blocking a flow of hydraulic fluid into the hydraulic cylinder. The input non-return valve 14 is configured for allowing hydraulic fluid to be drawn into the hydraulic cylinder 4 and is configured for blocking a flow of hydraulic fluid out of the hydraulic cylinder 4.

A high-pressure hydraulic line 16 is connected to the output of each hydraulic cylinder 4 and a low-pressure hydraulic line 17 is connected to the input of each hydraulic cylinder 4. The high-pressure hydraulic lines 16 and the low-pressure hydraulic lines 17 may form part of a hydraulic circuit.

The wave energy converter includes a tank 18. The tank 18 is used to store and/or provide hydraulic fluid. In the specific embodiment shown, the tank 18 is provided within the mounting body 2. The tank 18 is submerged under the water surface. In other embodiments not shown this may not be the case. The low-pressure hydraulic line 17 is fluidly connected to the tank 18. A cap 19 is provided to close the tank 18. The cap 19 may be removed, for example, for (re-)filling purposes.

The wave energy converter includes a hydraulic motor 5. The hydraulic motor 5 is configured to be driven or turned by compressed and/or pressurized hydraulic fluid. The hydraulic motor 5 is connected to an electric generator (not shown). Turning of the hydraulic motor 5 produces electric energy by the electric generator. In the specific embodiment shown, the hydraulic motor 5 is arranged within the mounting body 2 and the hydraulic motor 5 is submerged under the water surface. In other embodiments not shown, the hydraulic motor 5 may not be arranged within the mounting body 2 and/or may not be submerged. Instead of a hydraulic motor 5, a turbine may be used.

An input or inlet coupling 27 of the hydraulic motor 5 is fluidly connected to the high- pressure hydraulic line 16. An outlet or output coupling 28 of the hydraulic motor 5 is fluidly connected to the low-pressure hydraulic line 17 and/or the tank 18.

A fluctuating water surface causes the floating weights 3 to move upwards or downwards relative to the base. As a result, for example, during a downward movement of the floating weight 3, the respective piston 21 moves deeper into the respective hydraulic cylinder 4 and hydraulic fluid contained inside the hydraulic cylinder 4 gets compressed. The compressed hydraulic fluid leaves the hydraulic cylinder 4 via the output non-return valve 15 and is transferred via the high-pressure hydraulic line 16 to the input 27 of the hydraulic motor 5. The hydraulic motor 5 is driven by the compressed hydraulic fluid and electricity is produced by the electric generator that is connected to the hydraulic motor 5. Hydraulic fluid may then leave the hydraulic motor 5, e.g. via the output 28, and/or may be discharged into the tank 18. An upward movement of the floating weight 3 may cause the piston 21 to move further out of the hydraulic cylinder 4 such that hydraulic fluid is drawn into the hydraulic cylinder 4 via the input non-return valve 15.

In the specific embodiment shown, the base of the wave energy converter includes upper and lower stoppers 9. Upper stoppers 9 limit an upward pivot movement of the levers 6. Lower stoppers 9 limit a downward pivot movement of the levers 6. For each lever 6 an upper and/or a lower stopper 9 may be provided. In the specific embodiment shown, the stoppers 9 are provided on the mounting body 2. In the specific embodiment shown, the stoppers 9 are submerged under the water surface.

As indicated in Figure 1, a cooler 20 may be provided. The cooler 20 is configured for cooling the hydraulic fluid. In the specific embodiment shown, the cooler 20 is arranged on the mounting body 2 and is submerged under the water surface. Fins of the cooler 20 may be formed within a wall of the mounting body 2. The wall may at least partially surround the tank 18 such that the hydraulic fluid contained inside the tank 18 can be efficiently cooled.

The wave energy converter may further include at least one high-pressure stabilizer 8. The high-pressure stabilizer 8 is configured for stabilizing a hydraulic pressure of the hydraulic fluid within the high-pressure hydraulic line 16. In the specific embodiment shown, the high-pressure stabilizer 8 is arranged within the mounting body 2. In the specific embodiment shown, the high-pressure stabilizer 8 is submerged under the water surface. The high-pressure stabilizer 8 includes a hydraulic fluid reservoir which may be filled depending on the actual pressure inside the high-pressure hydraulic line. The hydraulic fluid reservoir may be arranged in or formed within a space inside the mounting body 2. The high-pressure stabilizer 8 includes a valve that connects the high-pressure hydraulic line 16 with the hydraulic fluid reservoir. In the specific embodiment shown, the valve includes a spring-loaded piston configured to abut on a corresponding valve seat of the valve. The spring-loaded piston is configured to lift off from the valve seat when the pressure inside the high-pressure hydraulic line 16 is larger than that of the hydraulic fluid reservoir. For example, during build-up of the hydraulic pressure within the high-pressure hydraulic line 16, the spring-loaded piston may lift off and the hydraulic fluid reservoir may get filled by hydraulic fluid. The spring-loaded piston lifts off or contacts the valve seat depending on the actual hydraulic pressure within the high-pressure hydraulic line 16.

The high-pressure stabilizer 8 may be adjustable for adjusting a pressure level and/or range within the high-pressure hydraulic line 16. For example, the spring-loaded piston may be pre-loaded and/or adjusted, for example by pumping air at several bars into the stabilizer 8. A lift-off behavior of the spring- loaded piston may be adjusted depending on the pre-load and/or air pressure provided to the stabilizer 8.

It is possible that more than one high-pressure stabilizer 8 is provided in the wave energy converter. The high-pressure stabilizers 8 may be adapted to different pressure levels and/or pressure ranges. For example, a spring-strength of the respective spring-loaded piston may be adjusted to an appropriate pressure level and/or range. For example, a first high-pressure stabilizer may include a spring that is adjusted such that a respective hydraulic cylinder starts filling at about 100 bar and stops filling at about 150 bar, a second high-pressure stabilizer may include a spring that is adjusted such that the respective hydraulic cylinders starts filling at about 150 bar and stops filling at about 200 bar, a third high-pressure stabilizer may include a spring that is adjusted such that a respective hydraulic cylinders starts filling at about 200 bar and stops filling at about 250 bar, and so on. These are only examples and shall not limit the scope of this disclosure.

The wave energy converter further includes a high-pressure safety valve 31. The high- pressure safety valve 31 is configured for limiting hydraulic pressure within the high-pressure hydraulic line 16 to a predetermined upper limit. The high-pressure safety valve 31 may be a one-way valve and/or a nonreturn valve. The high-pressure safety valve 31 is arranged upstream of the inlet 27 of the hydraulic motor 5 is provides a by-pass such that hydraulic fluid may bypass the hydraulic motor 5 when the hydraulic pressure within the high-pressure hydraulic line 16 approaches or exceeds the upper limit. In the specific embodiment shown, the high-pressure safety valve 31 and the bypass are arranged within the mounting body 2. In the specific embodiment shown, the high-pressure safety valve 31 and the bypass are submerged under the water surface.

The wave energy converter further includes a low-pressure safety switch 10. The low- pressure safety switch 10 is configured for switching off the hydraulic motor 5 when the hydraulic pressure within the high-pressure hydraulic line 16 approaches or is below a predetermined lower limit. The lower limit may be adjustable and/or may be set individually for the wave energy converter, as will be explained in more detail in connection with Figure 2. In the specific embodiment shown, the low-pressure safety switch 10 is arranged on the base and is submerged under the water surface.

As indicated in Figure 1, fastening sections 13 such as ears for bolts or screws 32 may be provided on the base, such as on the base element 1. The fastening sections 13 are configured for fastening at least one further wave energy converter to the base. A plurality of wave energy converters may be fastened, such as chain fastened, to one another. In the specific embodiment shown, two fastening sections 13 are arranged on opposite sides, such as opposite lateral sides, of the base element 1. A first wave energy converter may be fastened on a first side and another wave energy converter may be fastened on a second side of the base element 1 using the fastening sections 13.

As an example, the floating weight 3 may have a weight of at least 500 kg, preferably at least 1,000 kg, more preferably at least 2,500 kg, such as about 2,500 kg; and/or the hydraulic cylinder 4 may have a volume of at least 1,000 ml, preferably at least 2,000 ml, such as about 2,209 ml, and/or a volume of 6,000 ml or less, preferably 4,000 ml or less; and/or the lever 6 may have a length of at least 1 m, preferably at least 2 m, such as about 3 m, and/or a length of 6 m or less, preferably 5 m or less; and/or the hydraulic motor 5 may have a hydraulic motor volume of at least 10 ml, preferably at least 15 or at least 20 ml, such as about 22.7 ml, and/or a hydraulic motor volume of 70 ml or less, preferably 40 ml or less; and/or the hydraulic motor 5 may have a maximum power of at least 25 kW, preferably at least 40 kW, such as 51kW, and/or a maximum power of 100 kW or less, preferably 80 kW or less.

The skilled reader will understand that the above example is only one of many other possible examples. The above example shall thus not to be understood as limiting the scope of this disclosure.

Referring to Figure 2, a schematic view of a wave energy converter system is shown. The wave energy converter system includes multiple wave energy converters. Each wave energy converter may be identical and/or similar to the one explained in connection with Figure 1. In the example of Figure 2, the wave energy converter system includes four wave energy converters. In other examples not shown, the wave energy converter system may include any other suitable number. For example, the wave energy converter system may include 2, preferably at least 5, more preferably 10, more preferably at least 10 such as 12 wave energy converters.

As indicated in Figure 2, the wave energy converters may be placed on the seabed 23. The wave energy converters may be fastened to one another, such as chain fastened, for example, using, e.g., the fastening sections 13 arranged on the base element 1. Each wave energy converter includes a hydraulic motor 5 (or turbine) with an inlet 27 and an outlet 28. The high-pressure hydraulic lines 16 are fluidly connected to the inlet 27 and the low-pressure hydraulic lines 17 are fluidly connected to the outlet 28. The high-pressure lines 16 are fluidly connected to the output non-return valve 15 of each hydraulic cylinder 4 and the low- pressure hydraulic lines 17 are fluidly connected to the input non-return valve 14 of each hydraulic cylinder 4. A hydraulic circuit of interconnected high-pressure hydraulic lines 16 and interconnected low-pressure hydraulic lines 17 may be provided. Hydraulic fluid may circulate within the hydraulic circuit between the hydraulic cylinder 4, the hydraulic motor 5 and the tank 18. Figure 2 shows only some of the hydraulic lines that may be provided in the waver energy converter system. The hydraulic lines shown in Figure 2 are for illustration purpose only.

In other words, the high-pressure hydraulic lines 16 and or the low-pressure hydraulic lines 17 of two or more wave energy converters of the wave energy converter system may be fluidically coupled to each other.

Each wave energy converter may include a low-pressure safety switch, such as the low- pressure safety switch 10 of Figure 1. The low-pressure safety switch is configured for switching off the hydraulic motor 5 (or turbine) of the respective wave energy converter, when the hydraulic pressure approaches a predetermined lower limit or is below a predetermined lower limit.

In the wave energy converter system of Figure 2, the predetermined lower limit may be set independently for each wave energy converter. For example, if the hydraulic pressure drops, a first wave energy converter may be switched off while the other wave energy converters of the wave energy converter system may still be working and/or may still be switched on. Then, if the hydraulic pressure drops further, a second wave energy converter may be switched off, while the remaining other waver energy converters may still be working and/or may still be switched on. This shut-off procedure may continue until only one or no wave energy converter is still working. The predetermined lower limit for each wave energy converter may be set independently for each wave energy converter of the wave energy converter system. For example, a first wave energy converter in a system of, for example, ten wave energy converters may be switched off when the pressure approaches or drops below, e.g., 230 bar and may be switched on when the pressure approaches or exceeds, e.g., 260 bar. A second wave energy converter in the system may be switched off when the pressure approaches or drops below, e.g., 220 bar and may be switched on when the pressure approaches or exceeds, e.g., 250 bar, and so on. The lower limits may be set accordingly for each wave energy converter within the system. A shut off sequence may be provided for shutting off each of the wave energy converters depending on the respective lower pressure limit. Multiple commands or a single command for executing the shut-off sequence may be provided.

Waves 24 as schematically shown in Figure 2 cause the floating weights 3 of the system to ascend and/or descend and the kinetic energy of the waves is converted into electric energy, as explained in connection with Figure 1. The wave energy converter system of Figure 2 provides an ecofriendly way of producing electric energy.

A skilled reader will understand that the examples provided within the disclosure are for illustrating purposes only. Thus, the examples shall not be understood as limiting the scope of this disclosure. Many other suitable examples are possible.

The following is also part of the disclosure:

The invention in a broader sense belongs to the field of energy, and specifically refers to a wave energy converter. (IPC F03B13/14)

Due to the high level of environmental pollution and the need to protect the environment, future sources of electricity production are exclusively ecological. Given that there are still a lot of power plants operating on combustible materials, the need for new ecological sources of energy is inevitable.

The new wave energy converter is efficient and can be used for the production of electricity in all countries of the world that have access to the sea, it also serves as an engine for city water supply pumps, for sewage drainage pumps of all coastal cities, for supplying salt pans with sea water, etc. It is intended to be installed in the sea close to the coast or where the water is not too deep because the space from the bottom to the surface of the water is used. Due to the efficiency of production and assembly, this wave energy converter is constructed as a single element that is connected to several of the same elements and they all work together as a closed system, because 20 or more connected converters work in one system to achieve stable oil pressure pumping multiple hydraulic pistons. The floating weights rise with the waves, and when they descend, they push hydraulic pistons that pump high pressure oil into a hydro motor that turns a generator to produce electricity.

Figure 1 shows the converter in detail.

Figure 2 shows the operation of several connected converters.

This transducer has a base element 1 of concrete construction that has the appropriate weight to stand fixed and stable on the seabed 23 at the appropriate depth for the operation of the floating weights 3 that follow the surface of the water 24 during smaller and larger waves. The base element 1 has at least four adjustable legs 22, ears 13 for connecting the converters to each other with screws 32. The converter has two unidirectional hydraulic cylinders 4, two levers 6, two floating weights 3, a hydraulic motor 5, a metal body 2 attached to a number of concrete bolts 11 on a base element 1. Body 2 has the upper and lower lever stopper 9, tank 18 for hydraulic oil with finned cooler 20 and cap 19, low pressure switch 10, high pressure safety valve 31 and high-pressure oil stabilizer 8. The levers 6 are fixed on one side to the body of the converter on shafts 29 with bearings 7 allowing the shaft to move up and down with a limited stroke on the lower and the upper lever stopper 9. The levers 6 on the other side are fixed to the carrier 25 of the floating weight. The floating weight 3 has a suitable empty surface 26 so that it can stand most of it above the water and follow the surface of the water 24. The hydraulic cylinders 4 are attached with the piston lever 30 to the hydraulic cylinder mounts 12 which are fixed on the lower part of the lever 6 and the other side with the cylinder housing on the hydraulic cylinder mount 12 on the concrete base 1. The hydraulic cylinders 4 each have one inlet non-return valve 14 and one outlet non-return valve 15. High-pressure lines 16 are attached to the output valves of the hydraulic cylinders, which connect both hydraulic cylinders with the high- pressure oil stabilizer 8 and the hydraulic motor 5 to the inlet coupling 27. The output coupling 28 of the hydraulic motor is connected to the oil tank 18, and the tank with the inlet non-return valve 14 to the hydraulic cylinder 4, Figure 1. The hydraulic motor 5 is connected to the generator for power generation or water pump and so on. Multiple inverters are connected together and function as a single unit. When we connect 10 or more converters, they work in one closed system, so that the outputs of all hydraulic cylinders 4 are connected in the high-pressure hose line 16 to which all the hydraulic motors 5 are connected to the inlet couplings 27 and have the same oil pressure, Figure 2. The hydraulic motors have an output coupling 28 which is connected to the tank 18 and all the tanks 18 are connected in the low-pressure line 17 with inlet non-return valve 14 to all hydraulic cylinders 4. The wave energy converter works by the fact that when the floating weights move with the waves up, the hydraulic cylinders open and draw oil from the reservoir and when the weights go down, they push the pistons 21 down with their weight and create a high oil pressure that exits through the outlet check valves of the cylinders in the high pressure line and the inlet of the hydraulic motors, so that the oil from the hydraulic cylinders can only circulate through the hydraulic motors into the tank and again through the inlet check valves into the hydraulic cylinders 4. The high-pressure oil stabilizer 8 is installed in the high-pressure line 16, which has a pressure spring on the piston and as pressure is created in the high-pressure line, it fills and holds the reserve oil to maintain a stable pressure in the hydraulic motors that is needed at the moment when it happens that several pistons are in the charging phase at the same time. Hydraulic motors 5 on the high-pressure line 16 have installed a low-pressure switch 10, which is intended to turn off the hydro motors when the waves decrease and the oil pressure in the system drops. The low-pressure switches 10 are designed for each engine separately to turn it off at a certain pressure drop, arranged up to the last one that does not have a pressure cut-off switch to work even when the sea is calm, so that the last engine is supplied by all the converters with a smaller stroke of the pistons.

Examplel:

One wave energy converter having:

Floating weights of 2.5t each.

Levers for weights 3m long.

Hydraulic cylinders 4.7cm2 x 100cm (volume 2.209ml).

Hydraulic motor volume 22.7 ml, 51 kw maximum power.

The pistons are attached to the base and lever with a stroke of 3/1, so the weight of the weight is tripled in the hydraulic cylinder, so that 7.5t of weight in this cylinder diameter creates a pressure of 336 bar. The waves lift the weight on average 20 times per minute, the average piston stroke 30cm, that's 662.7ml x20 = 13.254ml x 2 pistons = 26.508ml of oil pushes one converter with two pistons into the hydraulic motor in one minute. So, with only one converter with 30 cm stroke of the pistons, we get an average of 26.5 L of oil flow per minute with a maximum pressure of up to 336 bar under load. A hydraulic motor with a volume of 22.7 ml and a maximum power of 51 kW requires 22.7 ml of oil for one revolution. 26,508 ml; 22.7 ml = 1,177.5 revolutions per minute, i.e., on twice the waves the piston opens 60 cm, and we get 2,335 revolutions per minute and on the biggest waves the pistons open 100 cm x 20 times per minute pushing 44.5 L per minute into the engine, i.e. one converter with two pistons 89 L or 3900 revolutions per minute which is almost the maximum flow of this hydraulic motor.

A possible aspect is: The wave energy converter is characterized by the fact that this converter has a concrete base (1) with a square shape that has at least four adjustable legs (22) for adjusting according to the terrain so that the base (1) stands flat on the bottom of the seabed (23), ears (13) for chain fastening the bases (1) one with the other with screws (32), on the upper surface of the base (1) there are several concrete bolts (11) embedded in the concrete and attached to them is a body (2) made of stainless steel, which has a tank (18) in the middle with a cap (19) and with finned cooler (20), shafts (29) and bearings (7) where levers (6) are attached, one on the left and the other on the right, which have a vertical stroke, limited to the upper and lower lever stoppers (9), at the ends they each have one floating weight (3) which have external carriers (25) for fastening with a lever (6) and inside a suitable empty surface (26) to stand and follow the surface of the water (24), the levers (6) have one hydraulic cylinder mount (12) each to which is attached one unidirectional hydraulic cylinder (4) with a piston lever (30) and on the other side hydraulic cylinder mounts (12) attached to a concrete base (1), where the hydraulic cylinders (4), each have an input non-return valve (14) and each an output non-return valve (15), where high-pressure lines (16) are attached to the output non-return valves (15) that connect botOh hydraulic cylinders with the high-pressure oil stabilizer (8) and with the hydraulic motor (5) to the inlet coupling (27), where the low pressure switch (10) is installed while the safety valve (31) connects the high pressure line (16) with the tank (18), also the output coupling (28) of the hydraulic motor is connected to the tank (18), and the tank (18) with low-pressure lines (17) connected to the inlet non-return valve (14) in the hydraulic cylinders (4).

The following aspects are preferred embodiments of the invention:

1. A wave energy converter for converting kinetic energy of waves into electric energy, the wave energy converter comprising: a base configured for being placed on a seabed (23), preferably wherein the base comprises a base element (1) and a mounting body (2), a first floating weight (3) configured for floating, preferably on a water surface, and following a movement of water, preferably of the water surface, caused by waves, a first lever (6) having a first end connected to the first floating weight (3) and a second end connected to the base, wherein the first lever (6) is pivotally connected to the base such that an ascending and/or descending movement of the first floating weight (3) causes the first lever (6) to pivotally move with respect to the base, a first hydraulic cylinder (4) and a first piston (21) slidably received within the first hydraulic cylinder (4), one of said first hydraulic cylinder (4) and said first piston (21) being connected to the base and the other one of said first hydraulic cylinder and said first piston (21) being pivotally connected to the first lever (6) or the first floating weight (3), preferably wherein a descending movement of the first floating weight (3) causes the first piston (21) to move deeper into the first hydraulic cylinder (4) thereby compressing hydraulic fluid provided within the first hydraulic cylinder (4), and an ascending movement of the first floating weight (3) causes the first piston (21) to move further out of the first hydraulic cylinder (4) thereby drawing hydraulic fluid into the first hydraulic cylinder (4), a first output non-return valve (15) connected to an output of the first hydraulic cylinder (4), the first output non-return valve (15) being configured for allowing a flow of compressed hydraulic fluid out of the first hydraulic cylinder (4) and blocking a flow of hydraulic fluid into the first hydraulic cylinder (4), a first input non-return valve (14) connected to an input of the first hydraulic cylinder (4), the first input non-return valve (14) being configured for allowing hydraulic fluid to be drawn into the first hydraulic cylinder (4) and blocking a flow of hydraulic fluid out of the first hydraulic cylinder (4), a high-pressure hydraulic line (16) connected to the first output non-return valve (15), a low-pressure hydraulic line (17) connected to the first input non-return valve (14), a hydraulic tank (18) connected to the low-pressure hydraulic line (17), and a hydraulic motor (5) or turbine coupled to an electric generator for producing electric energy, wherein an inlet (27) of the hydraulic motor (5) or turbine is coupled to the high-pressure hydraulic line (16) such that compressed hydraulic fluid is provided to the hydraulic motor (5) or turbine for turning the hydraulic motor (5) or turbine and producing electric energy by the electric generator preferably wherein an outlet (28) of the hydraulic motor (5) or the turbine is coupled to the hydraulic tank (18) for discharging hydraulic fluid into the hydraulic tank (18). The wave energy converter of aspect 1, wherein the base element (1) and/or the mounting body (2) are configured to be submerged; and/or wherein the mounting body (2) is connected to a top of the base element (1). The wave energy converter of aspect 1 or 2, wherein the second end of the first lever (6) is connected to the mounting body (2). The wave energy converter of any one of the preceding aspects, further comprising: a second floating weight (3) configured for floating, preferably on the water surface, and following a movement of the water, preferably of the surface, caused by waves, a second lever (6) having a first end connected to the second floating weight (3) and a second end connected to the base, preferably to the mounting body (2) and/or on a side opposite the first lever (6), wherein the second lever (6) is pivotally connected to the base, preferably to the mounting body (2), such that an ascending and/or descending movement of the second floating weight (3) causes the second lever (6) to pivot with respect to the base, preferably to the mounting body (2), a second hydraulic cylinder (4) and a second piston (21) slidably received within the second hydraulic cylinder (4), one of said second hydraulic cylinder (4) and said second piston (21) being pivotally connected to the base, preferably to the base element (1) and/or on a side opposite the side where the first hydraulic cylinder (4) or the first piston (5) is connected to the base, and the other one of said second hydraulic cylinder (4) and said second piston (21) being pivotally connected to the second lever (6) or the first floating weight (3), preferably wherein a descending movement of the second floating weight (3) causes the second piston (21) to move deeper into the second hydraulic cylinder (4) thereby compressing hydraulic fluid provided within the second hydraulic cylinder (4), and an ascending movement of the second floating weight (3) causes the second piston (21) to move further out of the second hydraulic cylinder (4) thereby drawing hydraulic fluid into the second hydraulic cylinder (4), a second output non-return valve (15) connected to an output of the second hydraulic cylinder (4), the second output non-return valve (15) being configured for allowing a flow of compressed hydraulic fluid out of the second hydraulic cylinder (4) and blocking a flow of hydraulic fluid into the second hydraulic cylinder (4), a second input non-return valve (14) connected to an input of the second hydraulic cylinder (4), the second input non-return valve (14) being configured for allowing hydraulic fluid to be drawn into the second hydraulic cylinder (4) and blocking a flow of hydraulic fluid out of the second hydraulic cylinder (4), wherein the high-pressure hydraulic line (16) is connected to the second output non-return valve (15), and the low-pressure hydraulic line (17) is connected to the second input non-return valve (14). The wave energy converter of any one of the preceding aspects, wherein the mounting body (2) is configured for mounting the hydraulic motor (5) thereon or therein, preferably wherein the hydraulic motor (5) is configured to be submerged under the water surface; and/or wherein the mounting body (2) is configured for mounting the hydraulic tank (18) thereon or therein, preferably wherein the hydraulic tank (18) is configured to be submerged under the water surface. The wave energy converter of any one of the preceding aspects, further comprising: a first upper stopper (9) for stopping and/or limiting an upward pivot movement of the first lever (6) and/or the first floating weight (3); and/or a first lower stopper (9) for stopping and/or limiting a downward pivot movement of the first lever (6) and/or the first floating weight (3); and/or a second upper stopper (9) for stopping and/or limiting an upward pivot movement of the second lever (6) and/or the second floating weight (3); and/or a second lower stopper (9) for stopping and/or limiting a downward pivot movement of the second lever (6) and/or the second floating weight (3); preferably wherein the first upper stopper (9) and/or the first lower stopper (9) and/or the second upper stopper (9) and/or the second lower stopper (9) is configured to be submerged under the water surface. The wave energy converter of aspect 6, wherein the first and/or second upper stopper and/or the first and/or second lower lever stopper (9) is arranged on the mounting body (2). The wave energy converter of any one of the preceding aspects, further comprising: a cooler (20) configured for cooling the hydraulic fluid, preferably wherein the cooler (20) is configured to be submerged. The wave energy converter of aspect 8, wherein the cooler (20) is arranged on the base, preferably on the mounting body (2). The wave energy converter of aspect 9, wherein the cooler (20) includes fins, preferably wherein the fins are arranged on a wall of the hydraulic tank (18), preferably wherein a wall of the hydraulic tank (18) is a wall of the mounting body (2). The wave energy converter of any one of the preceding aspects, further comprising: a high-pressure stabilizer (8) for stabilizing a hydraulic pressure of the hydraulic fluid within the high-pressure hydraulic line (16). The wave energy converter of aspect 11, wherein the high-pressure stabilizer (8) is arranged inside the base, preferably inside the mounting body (2). The wave energy converter of aspects 11 or 12, wherein the high-pressure stabilizer (8) includes a hydraulic fluid reservoir, preferably wherein the hydraulic fluid reservoir is formed by a space inside the base, preferably inside the mounting body (2). The wave energy converter of aspects 11, 12, or 13, wherein the high-pressure stabilizer (8) includes a valve connecting the hydraulic fluid reservoir with the high-pressure hydraulic line (16), preferably wherein the valve includes a spring-loaded piston abutting on a valve seat, wherein the spring-loaded piston lifts off from the valve seat during build-up of the hydraulic pressure within the high-pressure hydraulic line (16) such that the hydraulic fluid reservoir is filled with hydraulic fluid. The wave energy converter of aspect 14, wherein the spring-loaded piston lifts off or contacts the valve seat depending on an actual hydraulic pressure within the high-pressure hydraulic line (16) such that a substantially constant hydraulic pressure within the high-pressure hydraulic line (16) is maintained. The wave energy converter of any one of the preceding aspects, further comprising: a high-pressure safety valve (31) configured for limiting hydraulic pressure within the high- pressure hydraulic line (16) to a predetermined upper limit. The wave energy converter of aspect 16, wherein the high-pressure safety valve (31) is arranged upstream of the inlet (27) of the hydraulic motor (5) or turbine and wherein the high-pressure safety valve (31) provides a by-pass for by-passing the hydraulic motor (5) or turbine when the hydraulic pressure within the high-pressure hydraulic line (16) approaches or exceeds the predetermined upper limit. The wave energy converter of aspect 17, wherein the high-pressure safety valve (31) and preferably the by-pass are arranged inside or on the base, preferably inside or on the mounting body (2). The wave energy converter of any one of the preceding aspects, further comprising: a low-pressure safety switch (10) configured for switching off the hydraulic motor (5) or turbine when the hydraulic pressure within the high-pressure hydraulic line (16) approaches a predetermined lower limit or is below a predetermined lower limit. The wave energy converter of any one of the preceding aspects, wherein the base, preferably the mounting body (2), includes a first shaft (29) and a first bearing (7) for pivotally mounting the first lever (6) to the base, preferably to the mounting body (2); and/or wherein the base, preferably the mounting body (2), includes a second shaft (29) and a second bearing (7) for pivotally mounting the second lever (6) to the base, preferably to the mounting body (2). The wave energy converter of any one of the preceding aspects, wherein the first and/or second floating weight (3) has an annular and/or tubular shape with an open space and/or a middle opening (26). The wave energy converter of aspect 21, wherein the annular and/or tubular shape is filled with material for adjusting the weight of the floating weight (3); and/or wherein the first and/or second floating weight (3) has a weight of at least 500 kg, preferably at least 1,000 kg, more preferably at least 2,500 kg, such as about 2,500 kg. The wave energy converter of any one of the preceding aspects, wherein the first and/or second hydraulic cylinder (4) has a volume of at least 1,000 ml, preferably at least 2,000 ml, such as about 2,209 ml, and/or a volume of 6,000 ml or less, preferably 4,000 ml or less; and/or wherein the first and/or second lever (6) has a length of at least 1 m, preferably at least 2 m, such as about 3 m, and/or a length of 6 m or less, preferably 5 m or less; and/or wherein the hydraulic motor (5) has a hydraulic motor volume of at least 10 ml, preferably at least 15 or at least 20 ml, such as about 22.7 ml, and/or a hydraulic motor volume of 70 ml or less, preferably 40 ml or less; and/or wherein the hydraulic motor (5) has a maximum power of at least 25 kW, preferably at least 40 kW, such as 51kW, and/or a maximum power of 100 kW or less, preferably 80 kW or less. The wave energy converter of any one of the preceding aspects, wherein the base, preferably the base element (1) includes one or more fastening sections (13) for fastening at least one further wave energy converter according to any one of the preceding aspects to the base; preferably wherein the one or more fastening sections (13) are provided on lateral sides of the base, more preferably of the base element (1). The wave energy converter of any one of the preceding aspects, wherein a first fastening section (13) is provided on a first side of the base, more preferably of the base element (1), and wherein a second fastening section (13) is provided on a second side of the base, preferably of the base element (1), that is opposite said first side; preferably wherein the wave energy converter is configured to fasten the further wave energy converter via both the first fastening section (13) and the second fastening section (13). The wave energy converter of any one of the preceding aspects, wherein the base, preferably the base element (1), includes adjustable legs (22) for adjusting the position of the base on a terrain of the seabed. A wave energy converter system, comprising: a first wave energy converter according to any one of the preceding aspects, and at least one second wave energy converter according to any one of the preceding aspects, wherein the high-pressure hydraulic lines (16) of the wave energy converters are connected to one another, and the low-pressure lines (17) of the wave energy converters are connected to one another. A wave energy converter system of aspect 27, wherein each wave energy converter comprises a low- pressure safety switch (10), such as the low-pressure safety switch (10) of aspect 19, wherein the low- pressure safety switch (10) is configured for switching off the hydraulic motor (5) or turbine of the respective wave energy converter, when the hydraulic pressure approaches a predetermined lower limit or is below a predetermined lower limit. The wave energy converter system of aspect 28, wherein the predetermined lower limit is set independently for each wave energy converter. The wave energy converter system of aspects 27, 28 or 29, wherein the wave energy converters are fastened to one another, such as chain fastened to one another, using fastening sections, such as the fastening section (13) of aspect 22 arranged on each base of each wave energy converter. The wave energy converter system of any one of aspects 27 to 30, wherein a number of wave energy converters used in the wave energy converter system is 2, preferably at least 5, more preferably 10, more preferably at least 10 such as 12 or more.

Claims

1. A wave energy converter for converting kinetic energy of waves into electric energy, the wave energy converter comprising: a base configured for being placed on a seabed (23), preferably wherein the base comprises a base element (1) and a mounting body (2), a first floating weight (3) configured for floating, preferably on a water surface, and following a movement of water, preferably of the water surface, caused by waves, a first lever (6) having a first end connected to the first floating weight (3) and a second end connected to the base, wherein the first lever (6) is pivotally connected to the base such that an ascending and/or descending movement of the first floating weight (3) causes the first lever (6) to pivotally move with respect to the base, a first hydraulic cylinder (4) and a first piston (21) slidably received within the first hydraulic cylinder (4), one of said first hydraulic cylinder (4) and said first piston (21) being connected to the base and the other one of said first hydraulic cylinder and said first piston (21) being pivotally connected to the first lever (6) or the first floating weight (3), preferably wherein a descending movement of the first floating weight (3) causes the first piston (21) to move deeper into the first hydraulic cylinder (4) thereby compressing hydraulic fluid provided within the first hydraulic cylinder (4), and an ascending movement of the first floating weight (3) causes the first piston (21) to move further out of the first hydraulic cylinder (4) thereby drawing hydraulic fluid into the first hydraulic cylinder (4), a first output non-return valve (15) connected to an output of the first hydraulic cylinder (4), the first output non-return valve (15) being configured for allowing a flow of compressed hydraulic fluid out of the first hydraulic cylinder (4) and blocking a flow of hydraulic fluid into the first hydraulic cylinder (4), a first input non-return valve (14) connected to an input of the first hydraulic cylinder (4), the first input non-return valve (14) being configured for allowing hydraulic fluid to be drawn into the first hydraulic cylinder (4) and blocking a flow of hydraulic fluid out of the first hydraulic cylinder (4), a high-pressure hydraulic line (16) connected to the first output non-return valve (15), a low-pressure hydraulic line (17) connected to the first input non-return valve (14), a hydraulic tank (18) connected to the low-pressure hydraulic line (17), and a hydraulic motor (5) or turbine coupled to an electric generator for producing electric energy, wherein an inlet (27) of the hydraulic motor (5) or turbine is coupled to the high-pressure hydraulic line (16) such that compressed hydraulic fluid is provided to the hydraulic motor (5) or turbine for turning the hydraulic motor (5) or turbine and producing electric energy by the electric generator preferably wherein an outlet (28) of the hydraulic motor (5) or the turbine is coupled to the hydraulic tank (18) for discharging hydraulic fluid into the hydraulic tank (18). The wave energy converter of claim 1, wherein the base element (1) and/or the mounting body (2) are configured to be submerged; and/or wherein the mounting body

(2) is connected to a top of the base element (1).

3. The wave energy converter of claim 1 or 2, wherein the second end of the first lever (6) is connected to the mounting body (2).

4. The wave energy converter of any one of the preceding claims, further comprising: a second floating weight (3) configured for floating, preferably on the water surface, and following a movement of the water, preferably of the water surface, caused by waves, a second lever (6) having a first end connected to the second floating weight (3) and a second end connected to the base, preferably to the mounting body (2) and/or on a side opposite the first lever (6), wherein the second lever (6) is pivotally connected to the base, preferably to the mounting body (2), such that an ascending and/or descending movement of the second floating weight (3) causes the second lever (6) to pivot with respect to the base, preferably to the mounting body (2), a second hydraulic cylinder (4) and a second piston (21) slidably received within the second hydraulic cylinder (4), one of said second hydraulic cylinder (4) and said second piston (21) being pivotally connected to the base, preferably to the base element (1) and/or on a side opposite the side where the first hydraulic cylinder (4) or the first piston (5) is connected to the base, and the other one of said second hydraulic cylinder (4) and said second piston (21) being pivotally connected to the second lever (6) or the first floating weight (3), preferably wherein a descending movement of the second floating weight (3) causes the second piston (21) to move deeper into the second hydraulic cylinder (4) thereby compressing hydraulic fluid provided within the second hydraulic cylinder (4), and an ascending movement of the second floating weight (3) causes the second piston (21) to move further out of the second hydraulic cylinder (4) thereby drawing hydraulic fluid into the second hydraulic cylinder (4), a second output non-return valve (15) connected to an output of the second hydraulic cylinder (4), the second output non-return valve (15) being configured for allowing a flow of compressed hydraulic fluid out of the second hydraulic cylinder (4) and blocking a flow of hydraulic fluid into the second hydraulic cylinder (4), a second input non-return valve (14) connected to an input of the second hydraulic cylinder (4), the second input non-return valve (14) being configured for allowing hydraulic fluid to be drawn into the second hydraulic cylinder (4) and blocking a flow of hydraulic fluid out of the second hydraulic cylinder (4), wherein the high-pressure hydraulic line (16) is connected to the second output non-return valve (15), and the low-pressure hydraulic line (17) is connected to the second input non-return valve (14).

5. The wave energy converter of any one of the preceding claims, wherein the mounting body (2) is configured for mounting the hydraulic motor (5) thereon or therein, preferably wherein the hydraulic motor (5) is configured to be submerged under the water surface; and/or wherein the mounting body (2) is configured for mounting the hydraulic tank (18) thereon or therein, preferably wherein the hydraulic tank (18) is configured to be submerged under the water surface.

6. The wave energy converter of any one of the preceding claims, further comprising: a first upper stopper (9) for stopping and/or limiting an upward pivot movement of the first lever (6) and/or the first floating weight (3); and/or a first lower stopper (9) for stopping and/or limiting a downward pivot movement of the first lever (6) and/or the first floating weight (3); and/or a second upper stopper (9) for stopping and/or limiting an upward pivot movement of the second lever (6) and/or the second floating weight (3); and/or a second lower stopper (9) for stopping and/or limiting a downward pivot movement of the second lever (6) and/or the second floating weight (3); preferably wherein the first upper stopper (9) and/or the first lower stopper (9) and/or the second upper stopper (9) and/or the second lower stopper (9) is configured to be submerged under the water surface.

7. The wave energy converter of claim 6, wherein the first and/or second upper stopper and/or the first and/or second lower lever stopper (9) is arranged on the mounting body (2).

8. The wave energy converter of any one of the preceding claims, further comprising: a cooler (20) configured for cooling the hydraulic fluid, preferably wherein the cooler (20) is configured to be submerged.

9. The wave energy converter of claim 8, wherein the cooler (20) is arranged on the base, preferably on the mounting body (2).

10. The wave energy converter of claim 9, wherein the cooler (20) includes fins, preferably wherein the fins are arranged on a wall of the hydraulic tank (18), preferably wherein a wall of the hydraulic tank (18) is a wall of the mounting body (2).

11. The wave energy converter of any one of the preceding claims, further comprising: a high-pressure stabilizer (8) for stabilizing a hydraulic pressure of the hydraulic fluid within the high-pressure hydraulic line (16).

12. The wave energy converter of claim 11, wherein the high-pressure stabilizer (8) is arranged inside the base, preferably inside the mounting body (2).

13. The wave energy converter of claim 11 or 12, wherein the high-pressure stabilizer (8) includes a hydraulic fluid reservoir, preferably wherein the hydraulic fluid reservoir is formed by a space inside the base, preferably inside the mounting body (2).

14. The wave energy converter of claim 11, 12, or 13, wherein the high-pressure stabilizer (8) includes a valve connecting the hydraulic fluid reservoir with the high-pressure hydraulic line (16), preferably wherein the valve includes a spring-loaded piston abutting on a valve seat, wherein the spring-loaded piston lifts off from the valve seat during build-up of the hydraulic pressure within the high-pressure hydraulic line (16) such that the hydraulic fluid reservoir is filled with hydraulic fluid.

15. The wave energy converter of claim 14, wherein the spring-loaded piston lifts off or contacts the valve seat depending on an actual hydraulic pressure within the high-pressure hydraulic line (16) such that a substantially constant hydraulic pressure within the high-pressure hydraulic line (16) is maintained.

16. The wave energy converter of any one of the preceding claims, further comprising: a high-pressure safety valve (31) configured for limiting hydraulic pressure within the high- pressure hydraulic line (16) to a predetermined upper limit.

17. The wave energy converter of claim 16, wherein the high-pressure safety valve (31) is arranged upstream of the inlet (27) of the hydraulic motor (5) or turbine and wherein the high-pressure safety valve (31) provides a by-pass for by-passing the hydraulic motor (5) or turbine when the hydraulic pressure within the high-pressure hydraulic line (16) approaches or exceeds the predetermined upper limit.

18. The wave energy converter of claim 17, wherein the high-pressure safety valve (31) and preferably the by-pass are arranged inside or on the base, preferably inside or on the mounting body (2).

19. The wave energy converter of any one of the preceding claims, further comprising: a low-pressure safety switch (10) configured for switching off the hydraulic motor (5) or turbine when the hydraulic pressure within the high-pressure hydraulic line (16) approaches a predetermined lower limit or is below a predetermined lower limit.

20. The wave energy converter of any one of the preceding claims, wherein the base, preferably the mounting body (2), includes a first shaft (29) and a first bearing (7) for pivotally mounting the first lever (6) to the base, preferably to the mounting body (2); and/or wherein the base, preferably the mounting body (2), includes a second shaft (29) and a second bearing (7) for pivotally mounting the second lever (6) to the base, preferably to the mounting body (2).

21. The wave energy converter of any one of the preceding claims, wherein the first and/or second floating weight (3) has an annular and/or tubular shape with an open space and/or a middle opening (26).

22. The wave energy converter of claim 21, wherein the annular and/or tubular shape is filled with material for adjusting the weight of the floating weight (3); and/or wherein the first and/or second floating weight (3) has a weight of at least 500 kg, preferably at least 1,000 kg, more preferably at least 2,500 kg, such as about 2,500 kg.

23. The wave energy converter of any one of the preceding claims, wherein the first and/or second hydraulic cylinder (4) has a volume of at least 1,000 ml, preferably at least 2,000 ml, such as about 2,209 ml, and/or a volume of 6,000 ml or less, preferably 4,000 ml or less; and/or wherein the first and/or second lever (6) has a length of at least 1 m, preferably at least 2 m, such as about 3 m, and/or a length of 6 m or less, preferably 5 m or less; and/or wherein the hydraulic motor (5) has a hydraulic motor volume of at least 10 ml, preferably at least 15 or at least 20 ml, such as about 22.7 ml, and/or a hydraulic motor volume of 70 ml or less, preferably 40 ml or less; and/or wherein the hydraulic motor (5) has a maximum power of at least 25 kW, preferably at least 40 kW, such as 51kW, and/or a maximum power of 100 kW or less, preferably 80 kW or less.

24. The wave energy converter of any one of the preceding claims, wherein the base, preferably the base element (1) includes one or more fastening sections (13) for fastening at least one further wave energy converter according to any one of the preceding claims to the base; preferably wherein the one or more fastening sections (13) are provided on lateral sides of the base, more preferably of the base element (1).

25. The wave energy converter of any one of the preceding claims, wherein a first fastening section (13) is provided on a first side of the base, more preferably of the base element (1), and wherein a second fastening section (13) is provided on a second side of the base, preferably of the base element (1), that is opposite said first side; preferably wherein the wave energy converter is configured to fasten the further wave energy converter via both the first fastening section (13) and the second fastening section (13).

26. The wave energy converter of any one of the preceding claims, wherein the base, preferably the base element (1), includes adjustable legs (22) for adjusting the position of the base on a terrain of the seabed.

27. A wave energy converter system, comprising: a first wave energy converter according to any one of the preceding claims, and at least one second wave energy converter according to any one of the preceding claims, wherein the high-pressure hydraulic lines (16) of the wave energy converters are connected to one another, and the low-pressure lines (17) of the wave energy converters are connected to one another.

28. A wave energy converter system of claim 27, wherein each wave energy converter comprises a low- pressure safety switch (10), such as the low-pressure safety switch (10) of claim 19, wherein the low- pressure safety switch (10) is configured for switching off the hydraulic motor (5) or turbine of the respective wave energy converter, when the hydraulic pressure approaches a predetermined lower limit or is below a predetermined lower limit.

29. The wave energy converter system of claim 28, wherein the predetermined lower limit is set independently for each wave energy converter.

30. The wave energy converter system of claim 27, 28 or 29, wherein the wave energy converters are fastened to one another, such as chain fastened to one another, using fastening sections, such as the fastening section (13) of claim 22 arranged on each base of each wave energy converter.

1. The wave energy converter system of any one of claims 27 to 30, wherein a number of wave energy converters used in the wave energy converter system is 2, preferably at least 5, more preferably 10, more preferably at least 10 such as 12 or more.