Wave power generation device

Abstract

[Solution] The present disclosure provides a wave power generation device comprising: a floating wave collector (12) having a front end (18a) and a rear end (18b) adapted to float on the surface (14) of water (16); a platform (30) adapted to be submerged and located below the wave collector 12, the platform (30) adapted to allow the wave collector to move relative to the platform; an extendable front attachment (36a) connecting the front part of the wave collector to the platform; and an extendable rear attachment (36b) connecting the rear part of the wave collector to the platform; wherein in at least one configuration, the extendable front attachment and the extendable rear attachment are configured to control the wave collector such that the angle of attack (α) of the wave collector with respect to the incoming wave (20) increases when the front part of the wave collector contacts the incoming wave, and the wave collector (12) moves in a compound horizontal and vertical manner with the wave (20) to absorb the horizontal and vertical energy of the wave (20).

Description

Technical Field

[0001] The present disclosure relates to wave energy converters (WECs). The present disclosure also relates to a method of extracting wave energy using such wave energy converters and the like.

Background Art

[0002] Wave power generation is a technology for capturing the energy of (sea / ocean) waves for power generation and the like, and a machine that utilizes wave power generation is usually referred to as a wave energy converter (WEC). A plurality of types of wave energy converters have been proposed, such as surface attenuators, terminators, point absorber buoys, and oscillating wave surge converters. A surface attenuator uses a plurality of floating body segments connected to each other and generates movement between the segments in accordance with the movement of waves. An example of a terminator-type WEC is the Salter Duck, which has the shape of a duck or a cam and has a rotation axis near the water surface. A point absorber buoy generates power using the rise and fall of waves. That is, the point absorber buoy deals with the vertical movement of waves, that is, the system absorbs potential energy. An oscillating wave surge converter has a structure (inverted pendulum) in which one end is fixed to a structure or the seabed and the other end moves freely, and energy is recovered by the relative movement of the vibrating body with respect to the fixed point.

[0003] An example of an "inverted pendulum" is disclosed in US11028818 (OSCILLA POWER, INC), and the wave energy converter includes a surface float, a reaction structure, a plurality of flexible tethers, and a plurality of drive trains. Each flexible tether connects the surface float to the reaction structure. Each drive train is connected to a corresponding flexible tether. Each flexible tether has a length such that the system can be treated as an inverted pendulum, uses the horizontal surge movement of the surface float to generate tension in the corresponding drive train, and generates power by the horizontal surge movement.

[0004] Furthermore, US10767617, which has the same applicant as US11028818, discloses a wave power generator comprising a float body, a heave plate, a tether connecting the heave plate to the float body, and a controller for controlling the tether during survivability modes, each of which adjusts the tension and / or length of the tether. Various embodiments that may improve the survivability of US10767617 include raising the heave plate to the surface float, raising the heave plate close to the surface float without the two touching, and sinking the surface float by ballasting the float elements of the wave power generator so that the float elements of the wave power generator are in a negative buoyancy state and sink below the surface.

[0005] Furthermore, US2007257491A1 discloses an offshore device positioned in front of a breakwater and configured to receive waves arriving perpendicular to the long axis of the offshore device. The float chamber converts wave energy into mechanical energy along one or more known directions, namely rotation of the float chamber around its long axis. The float chamber has an axial profile that responds to changes in the water level perpendicular to the axis, as shown in Figure 15a of US2007257491A1, and the incoming waves rotate and tilt the float chamber forward and backward, as shown in Figures 15A and 15B of US2007257491A1. Mooring lines are attached to the front and rear portions of the float chamber, opposite each other on either side of the float chamber's center of gravity. The rotation of the float chamber around its axis causes the mooring lines to extend and contract. According to US2007257491A1, by using mooring lines on opposing sides and ends of each float chamber, the electroactive polymer device can expand and contract due to the multidirectional movement of the chamber (increasing height, rotation and tilting in relation to both incoming and transverse waves), allowing the offshore device to generate electricity in almost all wave directions and water level changes. [Overview of the Initiative]

[0006] Despite the numerous different wave power generation devices proposed, the object of this disclosure is to provide an improved wave power generation device that can extract more energy per wave, in particular.

[0007] According to a first aspect of the present disclosure, the present and other objectives are achieved by a wave power generation device comprising: a floating wave collector having a front and a rear end, adapted to float on the surface of water; a platform adapted to be submerged and located below the wave collector, the platform adapted (intended) for the wave collector to move relative to the platform; an extendable front attachment (36a) connecting the front part of the wave collector to the platform; and an extendable rear attachment connecting the rear part of the wave collector to the platform; wherein in at least one configuration, the extendable front attachment and the extendable rear attachment are configured to control the wave collector such that the angle of attack α of the wave collector with respect to an incoming wave increases when the wave collector contacts the incoming wave, and the wave collector moves in a compound horizontal and vertical direction with the wave to absorb the horizontal and vertical energy of the wave.

[0008] The angle of attack of the wave collector may be interpreted as the angle between the wave collector's reference line and the horizontal plane (still water surface). If the wave collector has an airfoil profile, the reference line is the chord of the airfoil. Furthermore, the platform should be considered the (substantial) fixed or stationary point of the wave power generator.

[0009] This disclosure is at least partially based on the understanding that more power can be extracted from waves by controlling the wave collector via forward and rear attachments. In particular, by controlling the wave collector so that the angle of attack α increases, for example, from about 0 degrees to about 10-45 degrees, the power extraction area of ​​the wave collector can be expanded, allowing the wave collector to better catch and ride the wave. As a result, the wave collector of the WEC of this disclosure can follow the wave for longer periods and distances than, for example, the surface float of US11028818. In particular, the horizontal distance over which the reaction force acts can increase by 3-4 times due to the ability to follow the wave. Furthermore, compared to conventional point absorber buoys that deal primarily with the vertical motion of waves, the WEC of this disclosure can extract power from both the horizontal and vertical directions of the wave.

[0010] Neither US11028818 nor USA2007257491A1 discloses controlling the wave collector via the forward and rear attachments so that the angle of attack with respect to the incoming wave increases and the wave collector moves in a compound horizontal and vertical direction with the wave.

[0011] The fact that the wave collector moves in a complex manner both horizontally and vertically with the wave means that the wave collector moves in the same direction, at least partially, as the wave direction of the incoming wave.

[0012] As the angle of attack of the wave collector increases relative to the incoming wave, the wave collector increases its hydrodynamic resistance and moves with the wave, absorbing its horizontal and vertical energy.

[0013] This has the further advantage that, as the angle of attack increases, the hydrodynamic resistance also increases, allowing the disclosed wave collector to efficiently control the amount of energy extracted from the wave. This is advantageous because, in large waves, the angle of attack is relatively small, avoiding overloading the system, while in small waves, the angle of attack is relatively large, allowing for the absorption of as much energy as possible.

[0014] The ability of wave collectors to avoid overload can be advantageous in that it allows for larger wave collectors, thereby improving the ability of wave power generators to extract energy from waves.

[0015] The wing shape of a wave collector allows for increased hydrodynamic resistance to incoming waves while maintaining low hydrodynamic resistance along the chord. This improves the wave collector's ability to move the wavefront upward from the trough to the crest, enabling it to absorb vertical energy from the wave for longer periods and over longer distances.

[0016] Therefore, the wing shape of the wave collector can increase its hydrodynamic drag in order to absorb energy by moving in a complex manner both horizontally and vertically with the wave.

[0017] Furthermore, controlling the wave collector via forward and rear attachments to reduce the angle of attack relative to incoming waves is advantageous because it reduces the hydrodynamic resistance of the wave collector, allowing it to glide or slide down through the wave and quickly return to its initial position, thereby absorbing power from the next incoming wave.

[0018] Furthermore, neither US11028818 nor US2007257491A1 discloses controlling the wave collector via the forward and rear attachments to increase the angle of attack relative to the incoming wave, allowing the wave collector to catch and ride the wave.

[0019] The meaning of the expression "wave collector" which allows you to catch and ride waves is explained below.

[0020] To capture a wave means that when the wave collector comes into contact with the wave at its trough, it absorbs the wave's kinetic energy due to its hydrodynamic resistance, and therefore moves together with the wave.

[0021] To "ride a wave" means that the wave collector absorbs kinetic energy from the wave (captures the wave) and, being constrained at least to some extent by the forward and rear attachments, moves upward relative to the wave, either above or below the water surface, from the trough to the crest.

[0022] Therefore, by capturing and riding the wave, the wave collector moves horizontally with the wave, and at the same time, glides from the trough to the crest of the wave, moving diagonally upward. Thus, the wave collector can follow the elliptical motion of the wave.

[0023] A wave trough can be defined as the lowest point of a wave in its period. A wave crest can be defined as the highest point of a wave in its period.

[0024] A wave collector with an airfoil shape may have the advantage of improving the wave collector's ability to move upward from the trough to the crest of a wave or to ride the wave.

[0025] A wave collector with an airfoil shape can have the added advantage of improving the wave collector's ability to move horizontally and vertically with the wave. Therefore, a wave collector with an airfoil shape can have the added advantage of improving the wave power generator's ability to absorb the horizontal and vertical energy of the wave. Absorbing the horizontal and vertical energy of the wave may mean absorbing the energy associated with the wave's motion in both the horizontal and vertical directions.

[0026] In addition, in a wave, as the wave passes, water particles trace circular or elliptical orbits. This motion is most prominent at the water surface and weakens with increasing depth. At the wave trough, the water particles move forward and upward. Then, as the wave passes, these particles move downward and backward.

[0027] A wave collector having an airfoil shape can have the further advantage of extracting energy from waves by the orbital path of water particles.

[0028] The airfoil shape may mean that the overall geometric shape is airfoil-like, such as having an airfoil cross-sectional profile. Alternatively, the airfoil shape may mean an overall geometric shape adapted to be streamline along the chord of the airfoil.

[0029] The angle of attack α can be increased in the range of 10 to 45 degrees when the wave collector contacts the oncoming wave. Further, the angle of attack α can be increased up to 30 degrees or up to 45 degrees. Further, the angle of attack α can be increased from approximately 0 degrees, such as 0 ± 5 degrees, or 0 ± 2 degrees, or 0 degrees.

[0030] The wave power generation device may further include means for determining the height of the oncoming wave. In at least one configuration, the telescopic front attachment and the telescopic rear attachment are configured to control the wave collector such that the angle of attack (α) with respect to the oncoming wave increases in the range of 10 to 45 degrees based on the height of the oncoming wave determined according to an inverse relationship between the angle of attack and the (wave) height. That is, the higher the oncoming wave, the lower the angle of attack, and vice versa. Thereby, overload can be avoided and / or the energy of the WEC can be optimized.

[0031] In at least one configuration, the rear attachment of the wave power generator is configured to shorten and lower the rear portion of the wave collector so that the angle of attack (α) with respect to the incoming wave increases when the wave collector contacts the incoming wave. At the same time, the front attachment can be kept substantially unchanged. This allows for an efficient increase in the angle of attack.

[0032] The buoyancy of the rear portion (28b) of the wave collector may be lower than that of the front portion (28a) of the wave collector. That is, the buoyancy of the wave collector can be considered to be offset toward the front end of the wave collector. This allows the rear portion of the wave collector to be lowered / pushed down, thereby increasing or at least promoting the angle of attack α.

[0033] The center of volume of the wave collector may be located in front of its center of gravity. This makes the wave collector "unstable," which means that the front end of the wave collector can quickly adapt to incoming waves.

[0034] In at least one configuration, the retractable forward attachment and the retractable rear attachment are configured to control the wave collector such that, at the end of the wave period, the angle of attack α decreases to, for example, 0 ± 5 degrees before the wave collector moves forward. By reducing the angle of attack (to 0 ± 5 degrees) at the end of the wave period, the shortening load required to return the wave collector to its initial position after riding a wave using the forward and rear attachments can be reduced. Furthermore, the speed at which the wave collector returns can be increased compared to when it is catching and riding the wave, which means that the time during which the reaction force acts and power is extracted can be increased. The wave period may be defined as from crest to crest (peak to peak) of the wave.

[0035] The wave collector is shaped such that its drag coefficient increases as the angle of attack α increases, and vice versa. In particular, the wave collector needs to have a geometric shape that has a low drag coefficient Cd2 when moving forward (angle of attack = 0 ± 5 degrees) and a high drag coefficient Cd1 when the angle of attack α increases (e.g., 10 to 45 degrees). For example, Cd1 may be approximately 50 × Cd2 when α is 45 degrees. Furthermore, as the angle of attack α increases, the mass increases, meaning that the volume and weight of water "stopped" by the wave collector moving higher up increases, which can increase the horizontal drag load.

[0036] The wave collector may be, for example, an airfoil wave collector and / or have an airfoil profile. This wave collector design reduces the shortening load required to return the wave collector to its initial position after riding a wave using the forward and rear attachments. At the same time, increasing the angle of attack can expand the power extraction area of ​​the wave collector.

[0037] In at least one configuration, the extendable front attachment and the extendable rear attachment are configured to control the wave collector such that, for each incoming wave, the angle of attack (α) of the wave collector initially increases in the range of 10 to 45 degrees, and then decreases to 0 ± 5 degrees. Thus, the angle of attack may repeatedly change during the operation of the wave power generator.

[0038] The front attachment comprises at least one front damper forming part of the (WEC) power extraction system and at least one front spring connected in parallel to the at least one front damper, and the rear attachment comprises at least one rear damper forming part of the power extraction system and at least one rear spring connected in parallel to the at least one rear damper. For example, at least one front damper may be at least one front hydraulic cylinder having at least one front piston and rod. Similarly, at least one rear damper may be at least one rear hydraulic cylinder having at least one rear piston and rod. At least one front spring may be at least one mechanical front spring. Similarly, at least one rear spring may be at least one mechanical rear spring.

[0039] The power take-off (PTO) system further comprises an accumulator connectable to the forward and rear dampers, each including a plurality of high-pressure (HP) output accumulators and high-pressure (HP) input accumulators of different pressures, and optionally the power take-off system further comprises a switch (49) that can control either the high-pressure output accumulator or the high-pressure input accumulator to selectively connect to at least one forward damper and / or at least one rear damper. By connecting the forward and / or rear dampers to different accumulators of the PTO system, various configurations of the WEC of this disclosure can be realized.

[0040] The wave power generator may further include a control unit adapted to control switches and / or which high-voltage output accumulators are connected to at least one forward damper and / or at least one rear damper, typically based on monitored data and / or characteristics of the wave power generator.

[0041] At least one configuration may include a (passive) configuration in which at least one rear spring is configured to shorten and pull down the rear portion of the wave collector such that the angle of attack α increases when the wave collector contacts and adapts to an incoming wave. If the buoyancy of the rear portion is lower than that of the front portion, the rear portion can be easily pulled down by at least one rear spring, but the front portion cannot be easily pulled down by at least one front spring because of its higher buoyancy. With this passive configuration, the wave collector follows the elliptical motion of the wave. In particular, in this passive configuration, the aspect ratio of the elliptical motion of the wave may be X:1, where X is in the range of 2 to 3.

[0042] At least one configuration may include an (active) configuration in which at least one rear spring and at least one rear damper are configured to shorten and pull down the rear portion of the wave collector such that the angle of attack α increases to, for example, 45 degrees when the wave collector comes into contact with an incoming wave. If at least one rear damper is at least one hydraulic cylinder, it may be configured to pull down the rear portion of the wave collector by connecting, for example, to the aforementioned high-pressure input accumulator that applies pressure to at least one rear hydraulic cylinder. When the buoyancy of the rear portion is low, less energy is required to pull down the rear portion by at least one rear damper, and more energy is recovered so that the wave collector can better catch and ride the wave and absorb more of the wave's horizontal energy. Typically, an active configuration can extract more energy than a passive configuration. In an active configuration, the wave collector follows the elliptical motion of the wave. In particular, in this active configuration, the aspect ratio of the elliptical motion of the wave may be X:1, where X is in the range of 3 to 4.

[0043] After the rear section is lowered / pulled down (for example, in an active or passive configuration), at least one front and rear damper may be configured to extend when the wave collector is riding a wave, thereby extracting energy.

[0044] Additionally, at least one front and rear spring typically extends when the wave collector is riding a wave, before shortening to its original length at the end of the wave period to propel the wave collector forward. When the wave collector moves forward against the direction of the wave, it is typically not extracted by at least one front and rear damper.

[0045] In at least one configuration, the forward attachment of the wave power generator is configured to stiffen / stop towards the end of the wave period due to the extension of at least one forward spring, and the rear attachment is configured such that the wave causes the rear attachment to further extend towards the end of the wave period such that the angle of attack (α) decreases to 0 ± 5 degrees at the end of the wave period. This may result from at least one forward spring extending more than at least one rear spring when the wave collector is riding the wave. The rear attachment is configured such that the wave causes the rear attachment to further extend towards the end of the wave period, for example by connecting at least one rear damper / hydraulic cylinder to a (lower) high-pressure accumulator of the PTO system in response to extension of the rear attachment beyond a predetermined threshold.

[0046] Furthermore, at least one configuration includes a configuration in which the forward attachment of the wave power generator is configured to become more rigid when the wave collector rides a wave in response to an extension of the forward attachment exceeding a predetermined threshold, causing the wave collector to submerge and avoid the wave crest. This avoids overloading in the case of large waves. In particular, it prevents at least one forward and rear hydraulic cylinder from becoming overloaded and reaching its maximum extension position. For example, the predetermined threshold may be in the range of 60-90%, such as 70% of the extension of the forward attachment. For example, the forward attachment may be configured to become more rigid in response to an extension of the forward attachment exceeding a predetermined threshold when the wave collector rides a wave, by connecting at least one forward damper / hydraulic cylinder to the high-pressure input accumulator described above. Alternatively, the forward attachment may include at least one additional stronger (mechanical) spring that switches away from the forward attachment in response to an extension of the forward attachment exceeding a predetermined threshold.

[0047] In a further (fully submerged) configuration, the retractable forward and rear attachments are configured to shorten so that the wave collector is fully submerged, without altering the wave collector's buoyancy (and usually without lowering the platform). This helps avoid overloading in very rough seas. For example, in this configuration, the wave collector can be fully submerged to a depth of 5 meters. Furthermore, by lowering the platform, the wave collector can be fully submerged to a depth of, for example, 15 meters. The depth to which the wave collector is fully submerged may depend on the location, wave size, etc.

[0048] The (overall) buoyancy of the wave collector and the loads on the front and rear attachments may be selected so that the wave collector has a submersion level in the water ranging from 80% to 99%, such as approximately 90%. This means that the loads on the front and rear attachments only need to be increased by about 10% to completely submerge the wave collector in the fully submerged configuration described above. In other configurations, such as passive and active configurations, this submersion level (e.g., about 90%) allows the forces on the front and rear attachments to remain consistently high and very close to their maximum throughout the wave period. In this partially submerged configuration, the submersion level may vary, for example, between 80% and 100%. In this application, “submersion level” means Submersion level = 1 - (Wave collector's upward force - Wave collector's weight - Load of front and rear attachments) / Wave collector's upward force It can be defined as follows.

[0049] For example, the length of the wave collector may be in the range of 10 to 150 meters, preferably in the range of 50 to 100 meters, such as 50 meters. For example, the width (or chord length) of the wave collector may be in the range of 6 to 16 meters, such as 8 meters.

[0050] The platform is adapted so that the wave collector rotates around the center of the platform (56) to align with the incoming wave, preferably so that the wave collector is perpendicular to the wave direction / parallel to the front of the wave with its front end facing the incoming wave. This ensures highly efficient energy extraction from the wave. Here, the platform has, for example, an upper part to which the front attachment and rear attachment are connected. This upper section is rotatable about the platform's own axis relative to the platform's (non-rotatable) lower section.

[0051] The diameter of the maximum area occupied by the wave collector (82) when the wave collector captures incoming waves and rotates around the center of the platform is 200% or less, preferably 150% or less, of the length (L) of the wave collector. This results in a clear and compact water surface area, which is highly desirable, for example, when combining offshore wind power generation and wave power generation equipment.

[0052] The platform may be a mid-water platform. When in use, a mid-water platform may be moored to the seabed. Alternatively, in shallow waters, the platform may be installed on the seabed.

[0053] A second aspect of this disclosure provides a method for extracting wave energy using a wave power generator according to the first aspect, wherein a floating wave collector floats on the surface of water (16), a platform is submerged, and an extendable forward attachment and an extendable rear attachment control the wave collector such that the angle of attack (α) of the wave collector with respect to the incoming wave increases when the wave collector comes into contact with the incoming wave, and the wave collector moves in a compound horizontal and vertical manner with the wave to absorb the horizontal and vertical energy of the wave. This can be expressed as the wave collector capturing and riding the wave and absorbing the horizontal and vertical energy of the wave when it comes into contact with the incoming wave. This aspect may exhibit the same or similar features and technical effects as the first aspect, and vice versa.

[0054] A feature described in one mode may be incorporated into other modes, and the benefits of that feature are applicable to all modes in which it is incorporated.

[0055] Other purposes, features, and benefits of this disclosure will become apparent from the following detailed disclosure, including the attached claims and drawings.

[0056] In general, all terms used in the claims shall be interpreted according to their ordinary meaning in the art unless otherwise specifically indicated herein. Furthermore, the use of terms such as “first,” “second,” and “third” in this specification does not indicate any order, quantity, or importance, but rather is used to distinguish one element from another. References to “a / an / the [element, apparatus, part, means, process, etc.]” ​​shall be broadly interpreted as referring to the case where such element, apparatus, part, means, process, etc. is at least one, unless otherwise specifically indicated. The steps of any method described herein do not need to be performed in the strictly disclosed order unless otherwise specifically indicated.

[0057] These and other aspects of the Disclosure will be described in more detail with reference to the accompanying drawings illustrating one or more embodiments of the Disclosure. [Brief explanation of the drawing]

[0058] [Figure 1] Figure 1 is a perspective view of a wave power generation apparatus according to one or more embodiments of the present disclosure. [Figure 2] Figure 2 is a side view of the wave power generation apparatus shown in Figure 1. [Figure 3] Figure 3 is a partial view of an embodiment of the power extraction system for a wave power generation device. [Figure 4] Figures 4A and 4B show the angle of attack of the wave collector of the wave power generation device. [Figure 5] Figures 5A to 5B show various modes or configurations of wave power generation equipment. [Figure 6] Figures 6A to 6D show the modes / configurations of Figure 5A in more detail. [Figure 7] Figure 7A is a schematic top view of the wave collector's rotation, and Figure 7B is a schematic top view of the wave collector's maximum occupied area. [Figure 8] Figure 8 is a schematic perspective view illustrating the scalability of a wave power generation system. [Figure 9] Figures 9A and 9B show various electrical layouts in conjunction with the wave power generation equipment. [Modes for carrying out the invention]

[0059] This disclosure will be described with reference to the accompanying drawings. Features illustrated or described as part of one embodiment may be used in another embodiment to realize further embodiments. For the purpose of clarification, not all features of actual implementation examples are described herein. Various structures, systems and devices are illustrated schematically for illustrative purposes only and so as not to obscure detailed descriptions known to those skilled in the art. However, the accompanying drawings are included to describe and illustrate explanatory examples of the subject matter of this disclosure.

[0060] The terms and phrases used herein are understood and interpreted as having the same meanings as those understood by those skilled in the art. Throughout this specification, no special definitions of terms or phrases, i.e., definitions different from the ordinary and customary meanings understood by those skilled in the art, are implied or intended. Where a term or phrase has a special meaning, i.e., a meaning different from that understood by those skilled in the art, such a special definition is explicitly stated in the specification to directly and clearly define the special definition of the term or phrase.

[0061] Figures 1 and 2 illustrate wave power generators (WECs) 10 according to one or more embodiments of the present disclosure. The wave power generators 10 may be interpreted as terminator-type WECs.

[0062] The wave power generator 10 includes a wing-shaped floating wave collector 12. The wave collector 12 is adapted to float on the surface 14 of the water 16. Therefore, the wave collector 12 may be alternatively referred to as a surface collector. The water 16 is typically a sea or ocean, but may alternatively be, for example, a (large) lake.

[0063] The wave collector 12 has a front end 18a and a rear end 18b. Typically, the front end 18a and the rear end 18b are straight and parallel and extend in the longitudinal direction of the wave collector 12. During operation, the front end 18a faces the incoming wave 20, as shown by the arrow 22 indicating the wave direction in Figure 1. The longitudinal length L of the wave collector 12 is, for example, in the range of 10 to 150 meters, preferably in the range of 50 to 100 meters, such as 50 meters. A wave collector 12 with a length of 50 meters can extract approximately 1 MW of power depending on the wave conditions at the installation site.

[0064] Referring further to Figure 8, the wave power generator 10 is expandable, and more energy can be extracted by increasing the length of the wave collector 12. In Figure 8, the total length of the wave collector 12 is 2 × L2 ≈ 2 × power.

[0065] The wave collector 12 may have an airfoil profile (or cross section) 24. The airfoil profile 24 can give the wave collector 12 a desired variable drag coefficient, as will be further described below. The airfoil profile 24 is (substantially) uniform over the entire length L of the wave collector 12. The airfoil profile 24 may have a rounded front end corresponding to the front end 18a of the wave collector 12. The airfoil profile 24 may also have a rounded rear end corresponding to the rear end 18b of the wave collector 12, the radius of which may be smaller than the radius of which may be smaller than that of which may be smaller. The airfoil profile 24 also has a chord 26 connecting the front end 18a and the rear end 18b. The chord 26 can be treated as a reference line for the wave collector 12, and the angle of attack α of the wave collector 12 may be defined as the angle between the chord 26 and the horizontal plane or direction, for example, as shown in Figure 4A. For example, the length of the blade corresponding to the width W of the wave collector 12 may be in the range of 6 to 10 meters, such as 8 meters.

[0066] Furthermore, the buoyancy of the rear portion 28b of the wave collector 12 may be lower than that of the front portion 28a of the wave collector 12, that is, the buoyancy of the front portion 28a of the wave collector 12 is higher than that of the rear portion 28b of the wave collector 12. Here, the buoyancy of the wave collector 12 can be considered to be offset in the direction of the front end 18a of the wave collector 12. For example, the front portion 28a of the wave collector 12 may be the front / front half of the wave collector 12, and the rear portion 28b of the wave collector 12 may be the rear / rear half of the wave collector 12. For example, the ratio of the buoyancy of the rear half 28b to that of the front half 28a may be 1:n, where n is in the range of 2 to 10. For example, the low buoyancy of the rear portion 28b can be achieved by making the volume of the floating elements of the rear portion 28b smaller than that of the front portion 28a. Furthermore, the volume center of the wave collector 12 may be in front of the center of gravity of the wave collector 12.

[0067] The wave power generator 10 may further comprise a platform 30. During operation, the platform 30 is submerged and positioned lower than the wave collector 12. The wave collector 12 is intended to move relative to the platform 30, which is the (substantially) fixed or stationary point of the wave power generator 10. For this purpose, if the platform 30 is a mid-water platform as shown in Figure 1, the platform 30 needs to be firmly moored to the seabed 32 using mooring devices 34, such as four mooring devices 34. For example, the mooring devices 34 may be composite mooring lines, typically ropes and / or anchor chains. Alternatively, in shallow waters, the platform 30 may be installed on the seabed.

[0068] The wave power generation device 10 further includes an extendable front attachment 36a that connects the front part 28a of the wave collector 12 to the platform 30 (in front of it), and an extendable rear attachment 36b that connects the rear part 28b of the wave collector 12 to the platform 30 (behind it).

[0069] Referring further to Figure 3, the forward attachment 36a may comprise at least one forward damper 38a forming part of the power extraction system 40 of the WEC 10, and at least one forward (mechanical) spring 42a connected in parallel to the at least one forward damper 38a. That is, the forward damper 38a and the forward spring 42a are connected in parallel. For example, at least one forward damper 38a may be at least one forward hydraulic cylinder comprising at least one forward (movable) piston and rod 44a. One end of each of the parallel forward damper 38a and forward spring 42a may be connected to the platform 30, for example by a ball joint, and the other end (including the forward piston and rod 44a) may be connected to the wave collector 12 via a wire or rod (etc.) of the forward attachment 36a. Thus, the forward piston and rod 44a are pulled outward when the wave collector 12 catches a wave 20, as indicated by arrow 47a which also indicates the force from the wave. For example, at least one front spring 42a may be at least one front coil spring. At least one front spring 42a may be used to pre-tension the WEC 10. Furthermore, at least one front spring 42a may be configured to retract at least one front damper 38a to its initial position, as indicated by arrow 47b which also shows the shortening force from the front spring 42a. The (longitudinal / axial) extension / shortening of the front attachment 36a is achieved by the (simultaneous) extension / shortening of at least one front damper 38a and at least one front spring 42a. In the embodiment shown in Figure 1, the front attachment 36a comprises two front dampers 38a (e.g., two front hydraulic cylinders each having a front piston and a rod 44a) and two front springs 42a (and thus two wires / rods 46a).

[0070] Similarly, the rear attachment 36b may comprise at least one rear damper 38b forming part of the power extraction system 40 of the WEC 10, and at least one rear (mechanical) spring 42b connected in parallel to the at least one rear damper 38b. That is, the rear damper 38b and the rear spring 42b are connected in parallel. For example, at least one rear damper 38b may be at least one rear hydraulic cylinder comprising at least one rear (movable) piston and rod 44b. One end of each of the parallel rear damper 38b and rear spring 42b may be connected to the platform 30, for example by a ball joint, and the other end (including the rear piston and rod 44b) may be connected to the wave collector 12 via a wire or rod (etc.) of the rear attachment 36b. This causes the rear piston and rod 44b to be pulled outward when the wave collector 12 catches a wave 20, as indicated by arrow 47a which also indicates the force from the wave. For example, at least one rear spring 42b may be at least one rear coil spring. At least one rear spring 42b may be used to pre-tension the WEC 10. Furthermore, at least one rear spring 42b may be configured to return at least one rear damper 38b to its initial position, as indicated by arrow 47b which also shows the shortening force from the rear spring 42b. As described above, the (longitudinal / axial) extension / shortening of the rear attachment 36b is achieved by the (simultaneous) extension / shortening of at least one rear damper 38b and at least one rear spring 42b. In the embodiment shown in Figure 1, the rear attachment 36b comprises two front dampers 38b (e.g., two rear hydraulic cylinders each having a rear piston and a rod 44b) and two rear springs 42b (and thus two wires / rods 46b). Therefore, this WEC10 has a total of four dampers 38a-b and four springs 42a-b.

[0071] The power extraction system 40 further comprises accumulators 48a to c. The accumulators 48a to c may comprise a plurality of high-pressure (HP) accumulators (outputs) 48a, each having different pressures such as high pressure, medium pressure, and low pressure. (Also) the accumulators 48a to c may comprise a high-pressure (HP) accumulator (input) 48b. The high-pressure (HP) accumulator (input) 48b may be connected to / supplied to one or more HP accumulators (outputs) 48a. (Also) the accumulators 48a to c may comprise a low-pressure (LP) accumulator (input) 48c. The HP accumulator (output) 48a may be up to 200 bar, the HP accumulator (input) 48b may be, for example, 100 bar, and the LP accumulator 48c may be 10 to 20 bar (should exceed the hydrostatic pressure at the current depth). The (output) pressure must be higher than the (input) pressure, for example, 200 bar (output) and 100 bar (input). The accumulators 48a-c may be connected to the damper / hydraulic cylinders 38a-b (upper chambers) as shown, for example, in Figure 3. In particular, the switch 49 of the power extraction system 40 may be controlled between two positions, (output) and (input), to selectively connect either the HP accumulator (output) 48a or the HP accumulator (input) 48b to the damper / hydraulic cylinders 38a and / or 38b. The default state of the switch 49 may be (output). Furthermore, only one of the HP accumulator (output) 48a may be connected at a time. By connecting the damper / hydraulic cylinders 38a-b to different HP accumulator (output) 48a, the pressure / load / stiffness / pre-tension of the damper / hydraulic cylinders 38a-b is adjusted (in stages, for example, from low to high). Typically, energy is generated / absorbed / stored in the power extraction system 40 when at least one forward and backward piston and rods 44a-b are extended (by the motion of the wave collector 12) and connected to one of the HP accumulators (outputs) 48a.

[0072] The power extraction system 40 may further include various valves, including the valve 50 shown in Figure 3. The power extraction system 40 may further include a hydraulic motor / turbine 51. The hydraulic motor / turbine 51 may be connected to an HP accumulator (output) 48a and an LP accumulator 48c. The power extraction system 40 may further include a generator 51. The generator 51 may be connected to the hydraulic motor / turbine 51. The power extraction system 40 may further include a compensating bladder (or low-pressure accumulator) 53. The compensating bladder 53 may be connected to the lower chambers of the damper / hydraulic cylinders 38a-b. The compensating bladder 53 may have a default pressure equal to the hydrostatic pressure at the current depth. A compensating bladder 53 connected to the lower chamber may be used to change the total force acting on the wave collector 12 (the total force depends on the Δ pressure from the upper and lower chambers) by changing the pressure, thereby allowing for finer-grained changes in the shortening force on the wave collector 12, and thus enabling more specific optimization of power extraction.

[0073] The power extraction system 40 may be located at least partially on and / or within the platform 30. Furthermore, the accumulators 48a-c may be common to the (two) front dampers 38a and the (two) rear dampers 38b, and the PTO system 40 may have switches 49 for each of the (two) front dampers 38a and the (two) rear dampers 38b, i.e., the PTO system 40 may have multiple switches 49.

[0074] As will be described in more detail below, the wave power generator 10 may further include a switch 49, and a control unit 54 applied to control the connection between damper / hydraulic cylinders 38a-b and one of the HP accumulators (outputs) 48a, typically via valves of the power extraction system 40, thereby achieving various configurations of the forward attachment 36a and the rear attachment 36b. The control by this control unit 54 may be based on monitored data and / or characteristics of the WEC 10, which may be one or more, such as wave height, spring position, piston position / motion / velocity, and extension of the forward / rear attachments. Furthermore, the control unit 54 may be adapted to calculate the position of the wave collector 12 in the wave 20 based on measured data (piston extension length, velocity, acceleration, etc.). The control unit 54 may include a computer and / or at least one processor, and software for executing commands to control the switch 49 and / or valves of the power extraction system 40.

[0075] Furthermore, as shown in Figures 1 and 7A, the platform 30 is adapted to align with the incoming wave 20 such that the wave collector 12 rotates about the center of the platform 30 (as indicated by reference numeral 56) and is perpendicular to the wave direction 22 (i.e., parallel to the front of the wave) with its front end 18a facing the incoming wave 20. For this purpose, the platform 30 may have an upper part 58a to which the front attachment 36a and rear attachment 36b are connected, the upper part 58a being rotatable about the axis 56 of the platform itself relative to the lower part 58b of the platform 30. If the platform 30 is a deepwater platform, the mooring device 34 described above is connected to the lower part 58b of the platform 30. Here, the wave power generator 10 may have a wave direction determination means 60, which may be adapted to rotate the wave collector 12 based on the determined wave direction 22 by, for example, using a hydraulic motor (not shown) to rotate the upper part 58a of the platform 30. For example, the wave direction determination means 60 may be a (wireless) communication unit adapted to remotely receive local sensors on the wave power generator 10, (actual and / or predicted) wave direction data, etc.

[0076] Generally, the retractable front attachment 36a and the retractable rear attachment 36b may be configured to control the angle of attack α of the wave collector 12 (e.g., by setting α and / or increasing α and / or decreasing α) by setting (e.g. by the control unit 54; before the wave 20) and optionally (e.g. by the control unit 543; during the wave period 62) the (shortening) load of at least one retractable front attachment 36a and / or at least one retractable rear attachment 36b.

[0077] For example, as shown in Figures 5A and 5B and 6A to 6D, according to embodiments of the present disclosure, the retractable front attachment 36a and the retractable rear attachment 36b may be configured to control the wave collector 10 such that the angle of attack (α) of the wave collector 12 with respect to the incoming wave increases from approximately 0 degrees, such as 30 degrees, to 10 to 45 degrees when the wave collector 12 contacts the incoming wave 20 (Figure 4), and the wave collector 12 catches the wave 20, rides the wave, and moves in a compound horizontal and vertical direction with the wave to absorb the horizontal and vertical energy of the wave. In particular, the low buoyancy of the rear portion 28b of the wave collector 12 makes it possible, or at least facilitates, lowering / pulling down the rear portion 28b to increase the angle of attack α. Furthermore, due to the shape / design of the wave collector 12 described above, when the angle of attack α is in the range of 10 to 45 degrees (Figure 4A), the wave collector 12 has an expanded power extraction area and a (higher) drag coefficient Cd1, resulting in a higher horizontal load F1 from the wave 20 acting on the wave collector 12, which allows the wave collector 12 to ride the wave for (longer) hours and distances, thereby enabling the WEC 10 to generate more energy. In addition, as the angle of attack α increases, the mass increases, i.e., the volume and weight of water that the wave collector 12, which is moving higher, "holds" increases, which can increase the horizontal (drag) load F1.

[0078] The retractable forward attachment 36a and the retractable rear attachment 36b are configured to control the wave collector 12 such that, at the end of the wave period, the angle of attack α decreases to 0 ± 5 degrees (Figure 4b) as the wave collector 12 adapts to the shape of the wave 20 before the wave collector 12 moves forward. Here, the wave collector 12 has a lower drag coefficient Cd2 due to the shape / design of the wave collector 12 described above, and the horizontal load F2 from the wave 20 acting on the wave collector 12 is lower (F1 >> F2). Furthermore, as the angle of attack α decreases, the mass, i.e., the volume of water that the flatter wave collector 12 "holds," decreases or does not increase substantially, so the horizontal (drag) load F2 may decrease. By reducing the angle of attack α to 0 ± 5 degrees, the shortening load required to return the wave collector 12 to its initial position after submerging in the wave using the forward and rear attachments or gliding across the water surface can be reduced, allowing the wave collector 12 to return at a faster speed compared to when it is catching and riding the wave (thus increasing the time during which energy can be generated in one cycle), and / or effectively avoiding overload.

[0079] In the (basic) operation of the wave power generator 10, corresponding to the method of extracting wave energy using the wave power generator 10, the buoyant wave collector 12 floats on the surface 14 of the water 16, and the platform 30 is submerged in the water 16.

[0080] The overall buoyancy of the wave collector and the loads of the front attachment 36a and rear attachment 36b may be selected so that when the wave collector 12 is in water, it has a submersion level in the range of 80-99%, such as approximately 90%. Submersion level = 1 - (Wave collector's upward force - Wave collector's weight - Load of front and rear attachments) / Wave collector's upward force It can be defined as follows.

[0081] In this example, the upward force of the wave collector is 5000kN, the weight of the wave collector is 1500kN, and the loads of the forward and rear attachments are 3000kN. The submersion level is 1-(5000-1500-3000) / 5000=90%.

[0082] Furthermore, as shown in Figure 7A, the wave collector 12 needs to align with the incoming wave 20, etc., (by rotation around the center 56 of the platform 30) so that the wave collector 12 is perpendicular to the wave direction 22 with its front end 18a facing the incoming wave. When the wave direction 22 changes during the operation of the WEC 10, the wave collector 12 also rotates.

[0083] Furthermore, the retractable forward attachment 36a and the retractable rear attachment 36b are used to control the wave collector 12 so that the angle of attack α of the wave collector 12 with respect to the incoming wave 20 increases, for example, from about 0 degrees to 10-45 degrees when the wave collector 12 makes contact with the incoming wave 20, so that the wave collector 12 catches the wave 20 and rides it. The movement of the wave collector 12 relative to the (fixed) platform 30 causes the forward and rear attachments 36a-b, which include at least one forward and rear piston and rods 44a-b, to extend, and energy is generated / absorbed / stored in the power extraction system 40. At the end of the wave period 62, the retractable forward attachment 36a and the retractable rear attachment 36b may control the wave collector 12 so that the angle of attack α decreases to 0 ± 5 degrees before the wave collector 12 moves forward to its initial position.

[0084] When a wave 20 passes through the wave collector 12, the wave height is reduced due to the wave collector 12. Thus, the WEC 10 / wave collector 12 has the ability to calm waves. This is advantageous, for example, when combined with offshore wind power generation, where by placing one or more WEC 10s in front of the wind turbine generator with respect to the main wave direction 22, the sea behind the WEC 10 can be calmed, which facilitates access to and / or maintenance of the wind turbine generator. In particular, the WEC 10 can extend the time available for maintenance of the wind turbine generator.

[0085] Various configurations of the retractable forward attachment 36a and the retractable rear attachment 36b will be described in more detail with reference to Figures 5A to 5E and 6A to 6D. In Figures 6A to 6D, the wave period is 10.0 seconds, the wave length is 156.1 meters, and the wave height is 2 meters. Reference numeral 63 indicates the water surface reference level, also referred to as the calm water line / level or calm sea level. Reference numeral 65 indicates the wavehead. As shown in Figure 5A, reference numeral 62 may be defined as the area between peaks.

[0086] In the first active configuration shown in Figures 5A and 6A to 6D, at least one rear spring 42b and at least one rear damper / hydraulic cylinder 38b may be configured to shorten and pull down the rear portion 28b of the wave collector 12 such that the angle of attack α increases to, for example, 45 degrees when the wave collector 12 contacts the incoming wave 20. Here, the wave collector 12 may have an initial position, as shown in Figure 6A, in which the wave collector 12 is positioned more or less above the platform 30 at the trough of the wave and is substantially horizontal (angle of attack α is 0 ± 5 degrees). The initial position may be the foremost position of the wave collector 12. The rear section 28b of the wave collector 12 is shortened to its natural length (and thus pulled down) by at least one rear spring 42b, as shown by arrow 66, due to the shortening of at least one rear damper / hydraulic cylinder 38b and the low buoyancy of the rear section of the wave collector 12. The front section 28a is not pulled down by at least one front spring 42a, at least due to its relatively high buoyancy, and as a result, the angle of attack α (α ≈ 25 degrees in Figure 6B) increases. Looking at the time slider to the right, we can see that the length of the front attachment 36a is substantially the same in Figures 6A and 6B, while the length of the rear attachment 36b is shorter in Figure 6B than in Figure 6A (by about 4 meters).

[0087] At least one rear hydraulic cylinder 38b may be configured to shorten and pull down the rear section 28b by being controlled by the control unit 54 to set switch 49 to (input) when the wave collector 12 is in its foremost position, and the HP accumulator 48b applies pressure to at least one rear hydraulic cylinder 38b, causing at least one rear hydraulic cylinder 38b to pull down the rear of the wave collector 12. That is, at least one rear damper / hydraulic cylinder 38b is here actively shortened by operating switch 49. Because the rear section 28b has low buoyancy, less energy is required to further lower the rear section 28b, allowing the wave collector 12 to better capture the wave 20, ride the wave 20, absorb more of the wave 20's horizontal energy, and obtain more energy to be consumed. For at least one front damper / hydraulic cylinder 38a, switch 49 may here be in the default setting (output).

[0088] Next, the wave 20 pushes the wave collector 12 backward, as indicated by arrow 68. Due to the increased angle of attack α and higher drag load, the wave collector 12 can ride the wave 20 for a longer time and distance, as shown in Figure 6C. As the wave collector 12 rides the wave 20, the forward attachment 36a extends, for example, from about 22 meters to about 26 meters. At this point, both at least one forward damper / hydraulic cylinder 38a and at least one forward spring 42a are extended, and the extended at least one forward damper / hydraulic cylinder 38a creates pressure in at least one of the HP accumulators (outputs) 48a. After the rear section 28b of the wave collector 12 is pulled down by at least one rear spring 42b and at least one rear damper 38b, and after the wave 20 begins to push the wave collector 12 backward, the switch 49 is set to (output), and under the control of the control unit 54, at least one rear damper 38b is connected to one of the HP accumulators (output) 48a, which preferably have the same pressure as the HP accumulator (input) 48b, and at least one rear damper 38b in addition to at least one front damper 38a also begins to extract energy. This may be actuated by the control unit 54 by measuring the motion and velocity of at least one front and rear piston and rod 44a~b. From Figures 6B and 6C, the rear attachment 36b extends approximately 2 meters. Therefore, the forward attachment 36a can extend longer than the rear attachment 36b when the wave collector 12 is riding a wave, and most of the energy is extracted by at least one forward damper / hydraulic cylinder 38a. In Figures 6A to 6D, the power output is 1165.6 kW, the maximum forward tension is 850 kN, and the maximum rear tension is 650 kN. The power output of a conventional wave buoy under the same conditions was only 306.3 kW. Note that the motion of the wave collector 12 in Figures 6A to 6D is schematic and was realized through computer simulation. From Figures 6B and 6C, it can be seen that the wave collector 12 is affected by both the hydrodynamic force and the potential energy of the wave 20.In particular, in Figures 6A to 6D, the horizontal movement of the center of the wave collector 12 is 7.8 meters, and the vertical movement of the center of the wave collector 12 is 2.9 meters.

[0089] Towards the end of wave 20 / wave period 62, at or near the peak (mountain) 80 of wave 20, the front attachment 36a may stiffen due to a longer extension of at least one front spring 42a (the return force from at least one front spring 42a is (substantially) equal to the force from wave 20 acting on the wave collector 12), and the rear attachment 36b may be configured to be further extended by wave 20 towards the end of wave period 62, such that the angle of attack α decreases to 0 ± 5 degrees at the end of wave period 62 (as indicated by arrow 70). The rear attachment 36b may be configured to allow the wave 20 to further extend the rear attachment 36b toward the end of the wave period 62 by controlling the control unit 54 to connect at least one rear damper / hydraulic cylinder 36b to a lower HP accumulator 48a of the power extraction system 40 in response to the rear attachment 36b extending beyond a predetermined threshold.

[0090] From a position in Figure 6D that may correspond to the innermost position of the wave collector 12, the wave collector 12 moves forward to the initial position in Figure 6A or against the direction of the wave, as indicated by arrow 72, due to at least one forward and rear spring 42a~b that shorten toward its natural length after the crest 80 of the wave 20 has passed. As the wave collector 12 moves forward, the forward and rear dampers / hydraulic cylinders 38a~b are connected to the LP accumulator 48c. This may be done via a mechanical check valve in the power extraction system 40. Thus, when the wave collector 12 moves forward, energy is typically not extracted by at least one forward and rear damper 38a~b. Furthermore, due to the decrease in angle of attack α and low drag load, the wave collector 12 can easily and quickly return to its initial position. It should be noted that the motion of water in the wave 20 is circular, and when the wave collector 12 is returning, it is also following the motion of water in the wave.

[0091] Once the wave collector 12 returns to its initial position, the angle of attack increases again, and this process is repeated. Thus, the angle of attack α can repeatedly change during the operation of the wave power generator 10. Furthermore, in the first active configuration, the wave collector 12 follows the elliptical motion 74 of the wave. In particular, in the active configuration, the aspect ratio of the elliptical motion of the wave may be X:1, where X is in the range of 3 to 4. Furthermore, in the first active configuration, the wave collector 12 can remain on the surface 14.

[0092] In a modified active configuration, at least one rear hydraulic cylinder 38b may be configured not to pull down the rear section 28b, and the switch 49 remains (output). Meanwhile, the HP (output) pressure remains controlled throughout the wave period, for example, high pressure, medium pressure, low pressure, etc.

[0093] A second passive configuration is shown in Figure 5B. The second configuration is similar to the first configuration, except that at least one rear damper / hydraulic cylinder 38b is configured not to pull down the rear portion 28b of the wave collector 12 (further), thereby the angle of attack α with respect to the incoming wave 20 does not increase as much as in the first active configuration. In other words, the rear portion 28b of this wave collector 12 does not go lower than that in the first configuration, as indicated by arrow 66'. Furthermore, the rear attachment 36b in this configuration is not connected to a lower HP accumulator 48a towards the end of the wave period 62. Consequently, the angle of attack α can also decrease towards the end of the wave period in the second / passive configuration, because the extension of the front attachment 36a usually stops before the extension of the rear attachment 36b stops due to the load from the dampers 38a~b and springs 42a~b. In the second / passive configuration, the wave collector 12 follows the elliptical motion of the (smaller) wave. In particular, in the passive configuration, the aspect ratio of the wave's elliptical motion may be Y:1, where Y is in the range of 2 to 3.

[0094] The wave power generator 10, and in particular its control unit 54, may be adapted, for example in a first or second configuration, to set an increased angle of attack α according to the height h of the incoming wave 20. In this regard, the wave power generator 10 further comprises a means 78 for determining the height h of the incoming wave, and the extendable front attachment 36a and extendable rear attachment 36b are configured to control the wave collector 12 such that the angle of attack α with respect to the incoming wave increases in the range of 10 to 45 degrees based on the height h of the incoming wave, which is determined according to the inverse relationship between the angle of attack α and the height h. That is, if the incoming wave 20 is high, the angle of attack α is low, and vice versa.

[0095] For example, the means 78 for determining the incoming wave height h may be a (wireless) communication unit adapted to remotely receive local sensors on the wave power generator 10, (actual and / or predicted) wave height data, etc. Furthermore, the means 78 for determining the incoming wave height h may be connected to the control unit 54.

[0096] In a passive configuration, for example, a specific angle of attack α may be set by controlling the control unit 54 to connect at least one forward and rear hydraulic cylinder 38a~b to an appropriate accumulator of the HP accumulator (output) 48a described above. In particular, in a passive configuration, the angle of attack does not change / increase during the wave period and is typically set for a large number of periods. In other words, in a passive configuration, at least one forward and rear hydraulic cylinder 38a~b operates at one specific value (e.g., 200 bar).

[0097] In the active configuration, the angle of attack α during the wave period 62 may be adjusted, for example, by temporarily setting switch 49 to (input) so that at least one rear hydraulic cylinder 38b pulls down the rear of the wave collector 12 when the wave collector 12 comes into contact with the incoming wave 20, and / or by temporarily connecting at least one rear damper / hydraulic cylinder 38b to a lower HP accumulator 48a towards the end of the wave period 62. That is, in the active configuration, the control unit 54 may adjust the load of at least one rear hydraulic cylinder 38b during the wave period.

[0098] Furthermore, the load / rigidity of the dampers / hydraulic cylinders 38a~b may be adjusted based on the (current / predicted) wave period and / or the (current / predicted) mean water level.

[0099] Figure 5C shows a third standby configuration. The third configuration is similar to the second configuration, except that the front and rear dampers / hydraulic cylinders 38a-b may be connected to the LP accumulator (output) 48c for the entire wave period, and only the front and rear springs 42a-b are in operation. In the third configuration, the wave collector 12 follows the circular motion (1:1) of the wave.

[0100] Figure 5D shows a fourth partial submersion configuration. The fourth configuration is similar to the first or second configuration, except that when the wave collector 12 rides a wave 20, the forward attachment 36a is configured to become more rigid in response to extension exceeding a predetermined threshold of the forward attachment 36a, thereby allowing the wave collector 12 to automatically submerge at the crest 80 of the wave 20 (and thus avoid the crest 80 of the wave 20). This avoids overloading when the wave 20 is large. For example, the predetermined threshold is in the range of 60-90%, such as 70%. For example, the forward attachment 36a is configured to become more rigid in response to extension exceeding a predetermined threshold of the forward attachment 36a when the wave collector 12 rides a wave 20, by controlling the control unit 54 to set switch 49 to (input) and connecting at least one forward damper / hydraulic cylinder 38a to the HP accumulator (input) 48b of the power extraction system 40.

[0101] Figure 5E shows a fifth fully submerged configuration. Here, the retractable front attachment 36a and the retractable rear attachment 36b are configured to shorten so that the wave collector 12 is fully submerged in the water 14, without changing the buoyancy of the wave collector 12. This may be achieved by increasing the load on the front and rear attachments 36a and rear so that the load on the front and rear attachments 36a and rear is greater than the rise due to the buoyancy of the wave collector 12, in particular by controlling the control unit 54 to connect at least one front and rear damper / hydraulic cylinder 38a and rear b to a higher pressure HP accumulator (output) 48a of the power extraction system 40. Alternatively or additionally, the spring stiffness / constant of at least one front and rear spring 42a and rear b may be increased (increased pre-tension). For example, in the fifth configuration, the wave collector may be fully submerged to a depth of 5 meters. The wave collector 12 can be submerged to a depth of 15 meters, for example, by lowering the platform 30 as well.

[0102] A first variation of the fifth configuration is similar to the first active configuration described above, but the wave collector 12 is completely submerged. A second variation of the fifth configuration (Figure 5E) is similar to the second passive configuration described above, but the wave collector 12 is completely submerged. A third variation of the fifth configuration is similar to the fourth standby configuration described above, but the wave collector 12 is completely submerged.

[0103] Power extraction in TIFF2026519854000002.tif60112 was rankable for each configuration, with the order being 1>2>4>5_1>5_2 (configurations 3 and 5_2 had zero power extraction).

[0104] The wave power generator 10, and especially its control unit 54, is adaptable to select which configuration to operate in depending on the height h and wave period of the incoming wave 20, etc., and the height h is determined by means 78. When the waves are small, a sharp angle of attack α is typically desirable, and the wave power generator 10 can select the first active configuration. The first active configuration is also useful for (very) long and (very) short wave periods. When the waves are high (e.g., 5 meters), a small angle of attack α is sufficient, and the wave power generator 10 can select the second passive configuration. As mentioned above, when the angle of attack is large, energy is required to shorten the rear portion 28b of the wave collector 12, so a lower angle α for higher waves is mainly to optimize energy. For even higher waves, the wave power generator 10 can operate in a fourth partially submerged configuration to avoid overload. And when the sea is very rough, the control unit 54 submerges the wave collector 12 to avoid an even greater load (= fifth configuration).

[0105] Moving to Figure 7B, the diameter of the maximum occupied area 82 of the wave collector 12 when it catches an incoming wave such as wave 20 and rotates around the center of the platform is 200% or less, preferably 150% or less of the wave collector's length L. This makes the water surface area clear and compact, which is very desirable, for example, when combining offshore wind power generation and wave power generation equipment. In the example where the length L of the wave collector 12 is 50 meters, the diameter of the occupied area 82 may be 60 to 70 meters. In Figures 7A and 7B, the rectangle 84 shows from above the area occupied by the wave collector 12 when it rides an incoming wave and then returns to its initial position. An example of rectangle / area 84 is L × Hm meters, where L is the length L of the wave collector 12 and hm is the horizontal motion of the wave collector 12 when it rides wave 20 and then returns to its initial position (indicated by arrow 85). For example, rectangle / area 84 is approximately 50 × 8 m 2 That is the case.

[0106] Figures 9A and 9B show various electrical layouts in conjunction with the wave power generation device 10.

[0107] In Figure 9A, the wave power generator 10 is connected to a wind turbine generator (WTG) 86. In particular, the generator 53 of the power extraction system 40 of the WEC 10 may be connected to the switchgear 88 of the WTG 86. The wind turbine generator 86 may further include a medium voltage unit 90 and an inverter 92. Typically, the medium voltage unit 90 and inverter 92 are existing elements of the WTG 86, and to connect an existing wind turbine generator 86 to the wave power generator 10, only the addition / incorporation of a switchgear is required. The inverter 92 may provide an output of 66 to 132 kV. The wave power generator 10 and the wind turbine generator 86 together can form a system 94.

[0108] In Figure 9B, the wave power generation device 10 includes a medium-voltage unit 94 and an inverter 96. This provides a more complete wave power generation device 10. The medium-voltage unit 94 is connected between the generator 53 and the inverter 96. The inverter 96 may provide an output of 66 to 132 kV.

[0109] It will be apparent to those skilled in the art that this disclosure is not limited in any way to the preferred embodiments described above. Rather, numerous modifications and variations are possible within the scope of the claims. For example, mechanical dampers may be used instead of the hydraulic cylinders 38a-b.

[0110] Furthermore, if, for example, the platform is located on the seabed, the platform may be excluded from the scope of WEC10.

[0111] Furthermore, certain features may be implemented without necessarily controlling the wave collector so that the angle of attack α increases when the wave collector comes into contact with the incoming wave, such as, but are not limited to, the partially submerged configuration of claim 16, the fully submerged configuration of claim 17, the rotatable platform and / or area of ​​claim 19, the scalable WEC of Figure 8, etc.

[0112] According to an alternative example, a wave power generation device is provided comprising: a floating wave collector 12 having a front end 18a and a rear end 18b, adapted to float on the surface 14 of water 16; a platform 30 adapted to be submerged and located below the wave collector 12, adapted so that the wave collector 12 moves relative to the platform 30; an extendable front attachment 36a connecting the front part of the wave collector to the platform; and an extendable rear attachment 36b connecting the rear part of the wave collector to the platform; wherein in at least one configuration, the extendable front attachment and the extendable rear attachment are configured to control the wave collector such that the angle of attack α of the wave collector with respect to the incoming wave 20 increases when the front part of the wave collector contacts the incoming wave, and the wave collector 12 moves in a compound horizontal and vertical direction with the wave 20 to absorb the horizontal and vertical energy of the wave 20.

[0113] This disclosure has been described above primarily with reference to a limited number of embodiments. However, it will be readily apparent to those skilled in the art that other embodiments are equally possible within the scope of this disclosure as defined in the attached claims.

[0114] Although the features and elements are described above in specific combinations, each feature and element may be used alone without other features and elements, or in various combinations with or without other features and elements.

[0115] In implementing the claimed invention, a person skilled in the art can understand and implement variations other than those disclosed from the drawings, disclosures, and the claims attached. In the claims, the word “equipped with” does not exclude other elements or processes, and the indefinite article “a” or “an” does not exclude plurals. A single processor or another unit may satisfy the functions of multiple matters described in the claims. The mere fact that certain features are described in different dependent claims does not imply that combinations of these features cannot be used advantageously. The symbol of intent in any claim should not be construed as limiting the scope.

Claims

1. A floating wave collector (12) having a wing-shaped profile and adapted to float on the surface (14) of water (16), having a front end (18a) and a rear end (18b), A platform (30) that is submerged and adapted to be located below the wave collector, wherein the wave collector is adapted to move relative to the platform (30), A retractable front attachment (36a) connects the front part of the wave collector to the platform (30), A retractable rear attachment (36b) connects the rear portion of the wave collector to the platform (30), Equipped with, In at least one configuration, the retractable front attachment (36a) and the retractable rear attachment (36b) are configured to control the wave collector (12) such that the angle of attack (α) of the wave collector (12) with respect to the incoming wave (20) increases when the front portion of the wave collector (12) comes into contact with the incoming wave (20), and the wave collector (12) moves in a compound horizontal and vertical manner with the wave (20) to absorb the horizontal and vertical energy of the wave (20). A wave power generation device (10) characterized by the following:

2. The wave power generation apparatus according to claim 1, wherein the angle of attack (α) increases in the range of 10 to 45 degrees when the wave collector comes into contact with the incoming wave.

3. The system further includes means (78) for determining the height (h) of the incoming wave, In at least one of the above configurations, the extendable front attachment and the extendable rear attachment are configured to control the wave collector such that the angle of attack (α) with respect to the incoming wave increases in the range of 10 to 45 degrees based on the height of the incoming wave, determined according to the inverse relationship between the angle of attack and the height. The wave power generation apparatus according to claim 1 or 2.

4. In at least one of the above configurations, the rear attachment of the wave power generator is configured to shorten and lower the rear portion of the wave collector such that the angle of attack (α) with respect to the incoming wave increases when the wave collector contacts the incoming wave. A wave power generation device according to any one of claims 1 to 3.

5. The wave power generation device according to any one of claims 1 to 4, wherein the buoyancy of the rear portion (28b) of the wave collector is lower than that of the front portion (28a) of the wave collector.

6. In at least one of the above configurations, the extendable front attachment and the extendable rear attachment are configured to control the wave collector such that, at the end of the wave period, the angle of attack decreases to 0 ± 5 degrees before the wave collector moves against the direction of the wave (20). A wave power generation apparatus according to any one of claims 1 to 5.

7. The wave power generation apparatus according to any one of claims 1 to 6, wherein the wave collector is shaped such that the drag coefficient increases as the angle of attack (α) increases.

8. The wave collector has an wing-shaped profile (24), according to any one of claims 1 to 7.

9. In at least one of the above configurations, the extendable front attachment and the extendable rear attachment are then configured to control the wave collector such that, for each incoming wave, the angle of attack (α) of the wave collector initially increases in the range of 10 to 45 degrees, and then decreases to 0 ± 5 degrees. A wave power generation device according to any one of claims 1 to 8.

10. The front attachment comprises at least one front damper (38a) that forms part of the power extraction system (40), and at least one front spring (42a) connected in parallel to the at least one front damper. The rear attachment comprises at least one rear damper (38b) that forms part of the power extraction system (40), and at least one rear spring (42b) connected in parallel to the at least one rear damper. A wave power generation device according to any one of claims 1 to 9.

11. The power extraction system (40) is an accumulator (48a-c) connectable to the front damper and the rear damper, and includes a plurality of high-pressure output accumulators (48a) and a high-pressure input accumulator (48b), each having different pressures. A switch (49) that can control either the high-voltage output accumulator (48a) or the high-voltage input accumulator (48b) to selectively connect to the at least one front damper and / or the at least one rear damper, The wave power generation apparatus according to claim 10, further comprising:

12. The wave power generator according to claim 11, further comprising a control unit (54) adapted to control the switch and / or which of the high-voltage output accumulators (48a) is connected to the at least one forward damper and / or the at least one rear damper, based on monitored data and / or characteristics of the wave power generator.

13. The wave power generation apparatus according to any one of claims 10 to 12, wherein the at least one configuration includes a configuration in which the at least one rear spring is configured to shorten and pull down the rear portion of the wave collector such that the angle of attack (α) increases when the wave collector contacts the incoming wave.

14. The wave power generation apparatus according to claim 10 or 12, wherein the at least one configuration includes the at least one rear spring and the at least one rear damper configured to shorten and pull down the rear portion of the wave collector such that the angle of attack (α) increases when the wave collector contacts the incoming wave.

15. In the above-mentioned at least one configuration, The forward attachment of the wave power generator is configured to stiffen towards the end of the wave period due to the extension of at least one forward spring, The rear attachment is configured such that the wave can further extend the rear attachment toward the end of the wave period such that the angle of attack (α) decreases to 0 ± 5 degrees at the end of the wave period. A wave power generation apparatus according to any one of claims 6 and 10 to 14.

16. The wave power generation device according to any one of claims 1 to 15, wherein the at least one configuration includes a configuration in which the forward attachment of the wave power generation device moves in a compound horizontal and vertical direction in response to an extension of the forward attachment that exceeds a predetermined threshold when the wave moves together with the incoming wave (20), becoming more rigid and causing the wave collector to submerge and avoid the wave crest (80).

17. In a further configuration, the retractable front attachment and the retractable rear attachment are configured to be shortened so that the wave collector is completely submerged in water, according to any one of claims 1 to 16.

18. The wave power generation device according to any one of claims 1 to 17, wherein the buoyancy of the wave collector and the loads of the front attachment and the rear attachment are selected such that the wave collector has a submersion level in water (16) of approximately 90% or in the range of 80 to 99%.

19. The platform is adapted so that the wave collector rotates about the center (56) of the platform to align with the incoming wave. When the wave collector moves in a compound horizontal and vertical direction with the incoming wave and rotates around the center of the platform, the diameter of the maximum occupied area (82) of the wave collector is 200% or less, preferably 150% or less, of the length (L) of the wave collector. A wave power generation apparatus according to any one of claims 1 to 18.

20. The buoyant wave collector (12) is made to float on the surface (14) of the water (16). The aforementioned platform was submerged in water, The retractable front attachment and the retractable rear attachment (36a-c) control the wave collector such that the angle of attack (α) of the wave collector with respect to the incoming wave increases when the front portion of the wave collector comes into contact with the incoming wave (20), and the wave collector (12) moves in a compound horizontal and vertical direction with the wave (20) to absorb the horizontal and vertical energy of the wave. A method for extracting wave energy using a wave power generation apparatus according to any one of claims 1 to 19.

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