Field

[001 ] The present disclosure relates to waver energy collectors, and more particularly to sea wave energy collectors.

Background

[002] Waves are generated by wind passing over a large surface of water. When the wind generated waves propagate slower than the wind speed just above the waves, there is an energy transfer from the wind to the waves. The energy contained in waves, especially sea and ocean waves, is clean, enormous and always regenerating, but not well utilized.

[003] In general, larger waves are more powerful but wave power is also determined by wave speed, wavelength and water density. Oscillatory motion of a sea wave is highest at the surface and diminishes exponentially with depth. However, for standing waves (clapotis) near a reflecting coast, wave energy is also present as pressure oscillations at great depth, producing microseisms. These pressure fluctuations at greater depth are too small to be interesting from the point of view of wave power.

[004] The waves propagate on sea or ocean surface, and the wave energy is also transported horizontally with the group velocity. The mean transport rate of the wave energy through a vertical plane of unit width, parallel to a wave crest, is called the wave energy flux (or wave power, which must not be confused with the actual power generated by a wave power device).

[005] In deep water where the water depth is larger than half the wavelength, the wave energy

flux is T _{e «} ( 0.5 ] H? T _e , where P is wave energy flux per unit of wave-crest length,

Y m ³ -s J

Hi is the significant wave height, T _e is the wave energy period, p is the water density and g is the acceleration by gravity. The above formula states that wave power is proportional to the wave energy period and to the square of the wave height. When the significant wave height is given in meters, and the wave period in seconds, the result is the wave power in kilowatts (kW) per meter of wave-front length or wavelength in short.

[006] In a sea state, the average (mean) energy density per unit area of gravity waves on the water surface is proportional to the wave height squared, according to linear wave theory: E = where E is the mean wave energy density per unit horizontal area (J/m ² ), the sum of kinetic and potential energy density per unit horizontal area. The potential energy density is equal to the kinetic energy, both contributing half to the wave energy density E, as can be expected from the equipartition theorem. In ocean waves, surface tension effects are negligible for wavelengths above a few decimeters.

[007] As waves propagate, their energy is transported. The energy transport velocity is the group velocity. As a result, the wave energy flux, through a vertical plane of unit width perpendicular to the wave propagation direction, is equal to P = E _Cg , with c _g the group velocity (m/s), where c _g = g

— T _e . Due to the dispersion relation for water waves under the action of gravity, the group velocity depends on the wavelength l, or equivalently, on the wave period T. Further, the dispersion relation is a function of the water depth h. As a result, the group velocity behaves differently in the limits of deep and shallow water, and at intermediate depths.

[008] Wave energy is most wasted. It would be advantageous if wave energy can be collected and utilized.

Summary of disclosure

[009] Wave energy collectors and methods of operating wave energy collectors for collecting kinetic energy from waves to generate electric power are disclosed.

[010] The wave energy collector of the present disclosure comprises a wave follower or a plurality of wave followers, a floatable station, a kinetic energy transformation arrangement, a kinetic power coupling arrangement and a dynamo. The wave follower comprises a floatable wave follower body which is to follow movement of a wave to collect kinetic energy therefrom. The kinetic energy transformation arrangement comprises a motion conversion mechanism for converting a kinetic energy collecting motion of the wave follower into a power generating motion of the kinetic power coupling arrangement for driving the dynamo into power generation motion. The wave follower is to move towards and away from the floatable station repeatedly in cycles and to move up and down relative to the floatable station repeatedly in cycles during wave energy collection operations.

[01 1 ] The floatable station may comprise a floatable body which is to function as a station buoy, a station platform which is at an elevated axial level above the station buoy, and a stay having a stay axis which elevates the station platform above the station buoy and which defines a main axis and an axial direction of the floatable station and the wave energy collector.

[012] The floatable station may have a buoyancy which is sufficient to keep the wave energy collector and the wave follower or the plurality of wave followers afloat under normal operation conditions. The wave follower has a buoyancy smaller than the buoyance of the floatable station. The floatable station and the wave follower or the plurality of wave followers may cooperate to maintain the wave energy in a normal working configuration when the wave energy collector is afloat on wavy water to perform wave energy collection operations with the dynamo and the kinetic power coupling arrangement above water.

[013] The floatable station has an in-water moment of inertia which may be at least 1.5 or 2 times larger than the in-water moment of inertia of the wave follower, and/or wherein the floatable station has a transversal extent which may be at least 1.5 or 2 times larger than the transversal extent of the wave follower.

[014] The wave follower is to execute a wave-following motion during a wave energy collection cycle. The kinetic energy transformation arrangement is to convert the wave-following motion into a power generation motion for driving the dynamo in to electrical power generation. The wave following motion may resemble an elliptical motion, a partial elliptical motion, a quasi-elliptical motion or a pendulum-like motion.

[015] The kinetic energy transformation arrangement may comprise a drive member. The drive member is to move up and down to drive the dynamo to generate electricity. The wave follower may be arranged to execute a non-linear wave-following motion during a wave energy collection cycle, and the kinetic energy transformation arrangement comprises a motion conversion arrangement to convert the non-linear wave-following motion into a linear up and down motion of the driver member.

[016] The floatable station has a main axis which is a vertical axis when the wave energy collector is placed on a horizonal surface. The kinetic energy transformation arrangement may comprise a linkage mechanism which extends in a radial direction with respect to the main axis to connect the wave follower with the floatable station and with a movable drive member. The movable driver is to move up and down relative to the floatable station to drive the dynamo during wave energy collection operations.

[017] The kinetic energy transformation arrangement may comprise a plurality of linkage mechanisms in connection with a corresponding plurality of wave followers. The linkage mechanisms are connected to move in synchronization, and wherein the wave followers are distributed to surround the floatable station.

[018] The wave followers may be distributed to define an outer periphery of the wave energy collector. The wave followers are located at corners of a regular polygon. The floatable station may be located at center of the polygon and surrounded by the wave followers. [019] The wave energy collector may have a transversal extent of approximately one wavelength or slightly larger than one wavelength of the wave on which the wave energy collector operates, the transversal extent being measured through the floatable station as a center.

[020] The wave follower and the floatable station may be separated by a separation distance such that when the wave follower at a wave crest, the floatable station is at a wave trough, and when the wave follower at a wave trough, the floatable station is at a wave crest.

[021 ] The wave follower and the floatable station may be configured such that the vertical center axes are approximately half-wavelength apart.

[022] The kinetic energy transformation arrangement may comprise a plurality of crank arm mechanisms and the crank arm mechanisms are distributed with uniform angular separation between adjacent crank arm mechanism.

[023] The crank arm mechanism may consist of a plurality of radially extending crank arm portions, wherein some of the crank arm portions are hinge joined and have a crank angle between adjacent crank arm portions, and wherein the crank angle is variable and is to change in response to wave following motion of the wave follower.

[024] The crank arm mechanism passes through the floatable station during wave energy collection operations of the wave followers.

[025] The wave follower is to move upwards relative to the floatable station to reach a top position which is above the floatable station and to move downwards relative to the floatable station to reach a bottom position which is below the floatable station.

[026] The wave energy collector of the present disclosure is operated by water waves moving the wave followers towards and away from the floatable station repeatedly or in cycles during wave collecting operations. The wave follower is also to move up and down relative to the floatable station during wave energy collection operations when the wave follower moves towards and away from the floatable station. When the wave follower moves up and down relative to the floatable station, the axial level of the wave follower relative to the floatable station changes. In example embodiments such as the present, the axial level of the wave follower relative to the floatable station increases when the wave follower moves up. The axial level of the wave follower relative to the floatable station increases to a maximum when the wave follower moves up to a maximum allowable axial extent; and the axial level of the wave follower relative to the floatable station decreases when the wave follower moves down. The axial level of the wave follower relative to the floatable station reaches a minimum when the wave follower moves down to the lowest allowable axial level. The axial level is measured with respect to an axis of the floatable station, for example, with reference to the stay axis or a center axis of the floatable body of the floatable station.

[027] The wave follower of the wave energy collector of the present disclosure is to operate to collect wave energy contained in sidewise or lateral components of waves in addition to up and down components of the waves. The kinetic energy transformation arrangement of the present disclosure is arranged to permit the wave follower to execute a pendulum-like motion to facilitate collection of wave energy embedded in both lateral and axial components of the waves. Lateral components of a wave herein mean sidewise or lateral components of the wave, which are components towards and away from the floatable station in the example embodiments. The sidewise or lateral components of the wave are components in a direction generally parallel to the direction of wave propagation. Axial components of a wave herein mean up or down components of the wave which are in a direction orthogonal to the direction of wave propagation. In example embodiments such as the present, the wave follower is to move in a quasi-elliptical path following the quasi-elliptical characteristics of waves.

[028] A method of collecting energy from waves of the present disclosure comprises: devising a wave follower to move relative to a floatable station to follow waves and to generate wave following motions, transforming wave-following motion a power generating motion for driving a dynamo and coupling the power generating motion to the dynamo. The wave-following motion resembles an elliptical motion, a partial elliptical motion, a quasi-elliptical motion or a pendulum like motion.

[029] The method comprises devising a plurality of wave followers to surround the floatable station, and connecting the wave followers to move in synchronization.

[030] The method comprises devising the wave followers at half-wavelengths.

[031 ] The method comprises devising the wave followers at vertexes of a regular polygon to surround the floatable station at center of the polygon.

[032] The method comprises devising the floatable to have a moment of inertia which is 2, 3, 4, 5, or 6 times, or a range or any ranges selected from the aforesaid values the moment of inertia of the wave follower.

Figures

[033] Example embodiments of the present disclosure are described by way of example and with reference to the accompanying Figures, in which; Figure 1A is a perspective view of an example wave energy collector 100 according to the disclosure,

Figure 1 B is a top plan view of the wave energy collector of Figure 1 A,

Figure 1 A1 is a perspective view of another example wave energy collector 100A according to the disclosure,

Figure 2A is a perspective view of an example wave energy collector 200 according to the disclosure,

Figure 2B is side view of the example wave energy collector 200,

Figure 3A is a perspective view of an example wave energy collector 300 according to the disclosure, and

Figure 3B is a side view of the example wave energy collector 300.

Description

[034] A wave energy collector of the present disclosure comprises one wave follower or a plurality of wave followers, a wave motion converter, a dynamo and a floatable station.

[035] The wave energy collector is for collecting kinetic energy from waves and to convert the kinetic energy carried or embedded in the waves into electrical energy. Wave energy is collected by the wave follower when the energy collector floats on a wavy water surface. During wave energy collection operations, the wave follower is to float on wavy water and to follow movements of waves on the wavy water surface to collect or capture kinetic energy therefrom. The wave follower comprises a floatable body which is to follow wave movements in order to capture kinetic energy from water waves during wave energy collection operations (or operations in short). The floatable body comprises at least a submerged portion which is submerged below water surface and at least an exposed portion which is above water surface. During example operations, the wave energy collector floats on water in order to collect kinetic energy from the water on which it floats. To collect kinetic energy carried by or contained by the waves, the wave follower, and more specially the floatable body of the wave follower, is to follow rippling motion of the water on the surface. The kinetic energy carried by or contained by the waves is transformed into kinetic energy useable for electric power generation when the wave follower moves relative to the floatable station.

[036] A floatable body has an outer periphery defining an outer surface and volume of the floatable body. The buoyancy of a floatable body is equal to the weight of liquid displaced by the floatable body. The portion of a floatable body which is immersed as a submerged portion is determined by the density of the floatable body and by relationship that immersed weight is total weight minus weight of displaced liquid. The floatable body may be a hollow body enclosed with a water-tight shell or a solid body made of a low-density material such as polystyrene. In general, the floatable body has an overall density of 50% or less, for example, between 20%-50%, the density of water on which it operates.

[037] The example floatable body of the example wave follower 112 comprises a cylindrical floatable body having a cylindrical axis extending between top and bottom ends, as depicted in Figures 1 A and 1 B. The cylindrical axis is a main axis of the floatable body and is orthogonal to a level surface when the bottom end of the floatable body rests on the level surface. The floatable body may have a larger ratio of transversal extent d to its axial extent l for better stability, the axial extent being measured along the direction of the cylindrical axis. When the floatable body is afloat on a clam water surface, the main axis is aligned with the vertical or the direction of gravity force and orthogonal to the horizon which defines a horizontal level.

[038] The floatable body may have other geometric shapes or configurations such as spherical, elliptical, prismatic (including rectangular prismatic or polygonal prismatic), polygonal (including multi-polygonal-faceted), or other shapes or non-geometric shapes or configurations without loss of generality.

[039] The floatable station comprises a floatable body 122, a platform 124 which is spaced apart from the floatable body 122, and a stay 126 which maintains a separation distance between the platform 124 and the floatable body 122. The floatable station is designed and configured such that when the wave energy collector floats on calm water or is placed on a horizontal-levelled surface, the platform 124 is at a vertical level above the floatable body and the vertical separation distance between the platform and the upper surface of the floatable body 122 is determined by the longitudinal extent of the stay 126.

[040] In embodiments such as the present, the floatable body 122 forms a support base of the floatable station to keep the floatable station afloat and defines a base portion of the wave energy collector. The example floatable body 122 comprises a first surface which is an upward-facing surface, a second surface which is a downward-facing surface, and a peripheral surface interconnecting the first and second surfaces.

[041 ] The platform 124 is a station platform having an upper platform surface which is upward- facing, a lower platform surface which is downward-facing, and a platform periphery surface interconnecting the upper platform surface and the lower platform surface. The upper platform surface and the lower platform surface are parallel and opposite facing and the platform periphery surface is defined by a platform peripheral wall which has a uniform thickness and defining the axial extent of the platform 124. The example platform 124 has a transversal extent, measured in a direction orthogonal to the axial extent. The transversal extent of the station platform is significantly smaller than the transversal extent of the floatable base body 122. In example embodiments, the ratio between the transversal extent of the floatable base body 122 and that of the station platform 124 is smaller than 30%, 25%, 20%, 15%, or a range or any ranges defined by selection of some or all of the aforesaid values. The transversal extent of the platform is measured in a direction orthogonal to the stay axis. The upward facing surface of the example platform 124 has an area which is substantially smaller than the first surface of the floatable base body 122. The example platform is geometrically similar to the geometry of the first surface of the floatable base body. In example embodiment such as the present, both the station platform 124 and the floatable base body 122 has a circular cross section and share a common center axis. In some embodiments, the axial level of the station platform 124 relative to the floatable body 122 is adjustable. The floatable body 122 of the floatable station may have a buoyancy which is sufficient to keep the entire wave energy collector afloat and in stability. The floatable body 122 of the floatable station is significantly bulkier than the wave follower, and may have a buoyancy of 2, 3, 4, or 5 times that of the floatable body of a wave follower.

[042] In general, the station platform, the stay and the floatable base body cooperate to define a stable floatable platform so that the power generator and associated equipment and circuits are kept above the water level even during rough conditions such as stormy conditions.

[043] The floatable platform is a strong, rigid and light structure with low wind-resistance coefficient to withstand strong winds and rough waves, since conditions in an open sea can be harsh and unpredictable. In some embodiments such as the present, the floatable base body is to function as a floating ballast, for example a ballasting buoy, to maintain stability of the entire wave energy collector to remain in an upward configuration even during extreme conditions. When the wave energy is in the upward configuration, the station platform 124 is above the upper surface of the floatable body 122. During operations, the floatable body 122 may be anchored, for example, anchored on sea floor or to a supporting structure by a flexible rope or cable. In example embodiments, a plurality of wave energy collectors is connected to form a matrix of floating wave energy collectors, with the wave energy collectors movable transversely in directions parallel to water surface in response to change in wind directions.

[044] The stay 126 is to elevate the station platform 124 from the floatable body 122 when the wave energy collector is afloat. The stay extends longitudinally in a longitudinal direction between the station platform 124 from the floatable body 122. The longitudinal direction is defined by a longitudinal center axis which is also a stay axis. In example embodiments such as the present, the stay comprises an elongate strut member having a longitudinal center axis which is also the stay axis. The stay axis is orthogonal to the upper surface of the floatable body and coaxial with the main axis of the floatable body 122. The stay may have a tripod-type structure, a tower-type structure such as a tower-frame type strut structure, or other support structure forms without loss of generality. The example strut member comprises an elongate tube having a tube axis which extends in the longitudinal direction defined by the longitudinal axis of the strut. The tube is preferably made of aluminum, aluminum alloy, or other light metal or light metal alloys which are corrosion and weathering resistant.

[045] The motion converter is a motion conversion mechanism comprising a driver, a driver guide and a linkage mechanism. The linkage mechanism connects the wave-follower with the driver and the floatable station. The driver guide has a driver guide axis and defines a track along which the driver is to move in a reciprocating manner or reciprocally during operations.

[046] The driver is to function as a power coupler or power coupling device to couple kinetic energy collected by the waver follower to kinetic energy for driving the dynamo whereby the kinetic energy is converted to electrical energy for use, for storage or for outward transmission. An example driver comprises a rigid driver member 142 which is freely slidable along the driver guide, as depicted in Figures 1A and 1 B. The driver member has a radial portion and a central aperture surrounded by the radial portion. An example driver member is formed from a light metal plate and the radial portion comprises an upper surface, a lower surface and a peripheral wall interconnecting the upper and lower surface. The central aperture is an inner aperture on the light metal plate and has a clearance sufficient to allow the driver to move along the driver guide with no or minimal friction, engagement or obstruction. The upper surface of the driver rr\err\ber142 defines a dynamo platform on which a dynamo is mounted.

[047] The example driver guide comprises a teethed track 144, as depicted in Figure 1A. The teethed track 144 is elongate and extends in a longitudinal direction away from the platform 124 and away from the floatable base body 122. In example embodiments such as the present, the teethed track 144 extends axially in a coaxial manner with the stay 126. The teethed track 144 has a longitudinal axis which is a center axis defining the longitudinal direction and the driver guide axis.

[048] The linkage mechanism comprises a first arm portion 162, a second arm portion 164 and a third arm portion 166. The first arm portion has a first end which is physically connected to a wave follower 122 and a second arm which is at a distance away from the wave follower. The second arm portion has a first end which is physically connected to the platform 124 and a second end which is physically connected with the first arm portion. The third arm portion has a first end which is physically connected to the driver member 142 and a second end which is physically connected with the first arm portion. Each example arm portion comprises a lever portion and the arm portions are preferably made of weathering resistant materials such as stainless steel, light metal alloy, or hard plastics, since the wave collector is expected to operate under harsh weathering conditions.

[049] In example embodiments such as the present, the first arm portion 162 and the second arm portion 164 cooperate to form a first crank arm, which is a crank arm having generally an inverted V shape. More specifically, the first arm portion and the second arm portion are integrally formed or joined to form a rigid first crank arm. The example first crank arm has an obtuse subtended angle between the first and second arm portions. For example, a subtended angle between 120 degrees to 145 degrees such as 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, or a range or any ranges defined by selection of some or all of the aforesaid values, with the opened end of the inverted V which defines the obtuse angle to oppositely face the floatable base body 122. In the example of Figure 1 A and other embodiments, the platform 124 is an anchoring platform on which the first crank arm 162, 164 is anchored by a hinge or a pivot, with the hinge axis or the pivot axis orthogonal to the struct axis or the longitudinal axis of the driver guide.

[050] In example embodiments such as the present, the first arm portion 162 and the third arm portion 166 cooperate to form a second crank arm having a generally inverted V shape. More specifically, the first arm portion and the third arm portion are hinge joined or pivot joined to form a second crank arm having a variable subtended angle between the first and third arm portions.

[051 ] The example second crank arm 162, 166 has an obtuse subtended angle between the first and third arm portions. For example, a subtended angle between 125 degrees to 160 degrees such as 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155 degrees, 160 degrees or a range or any ranges defined by selection of some or all of the aforesaid values, with the opened end of the inverted V which defines the obtuse angle to oppositely face the floatable base body 122.

[052] The example second and third arm portions are coplanar and have an acute angle subtended between them. The example acute angle is between 10 to 25 degrees, including 10 degrees, 15 degrees, 20 degrees, 25 degrees, or a range or any ranges defined by selection of some or all of the aforesaid values. In this example, the first, second and third arm portions are also coplanar and cooperate to define a plane which is parallel to the longitudinal axis of the driver guide.

[053] The first end of the example third arm portion 166 is hinge connected with the rigid drive member 142. The hinge connection between the example third arm portion 166 and the drive member 142 is on an underside of the drive member 142, as depicted in Figure 1A. The second end of the example third arm portion 166, which is distal from or not connected with the drive member 142, is hinge connected with the second end of the first arm portion 162. The first end of the example second arm portion 164 is hinge connected with the platform 124. The hinge connection between the example second arm portion 164 and the platform 124 is on an upper side of the platform 124, as depicted in Figure 1A.

[054] The second 164 and third 166 arm portions are hinge joined and cooperate to form a third crank arm. The third crank arm has a variable crank angle which is an acute angle. The instantaneous crank angle, which is the angle subtended between the second arm portion and the third arm portion, is dependent on the instantaneous axial level of the floatable body 122. The crank angle changes with the change in axial level of the wave follower relative to the axial level of the floatable body 122. More specifically, the crank angle increases when the difference between the axial levels increases, and the crank angle decreases when the difference between the axial levels decreases. Since the width of the crank arm at the open-end of the crank arm increase with the crank angle, the axial distance of the driver member 142 relative to the platform 124 also changes in the same manner. Specifically, the axial distance changes with the change in axial level of the wave follower 112 relative to the axial level of the floatable body 122. More specifically, the axial distance increases when the difference between the axial levels increases, and the axial distance decreases when the difference between the axial levels decreases.

[055] The example first arm portion 162 comprises a crank arm portion having an obtuse angle facing the floatable station. In some embodiments, the first arm portion has an arcuate shape and having a concave side facing the floatable station. The crank angles and crank arm lengths may be selected according to wavelength of the waves from which wave energy is to be collected.

[056] The example third crank arm which is formed by hinged connection of the second arm portion 164 and the third arm portion 166 is a V-shaped crank arm having a vertex and a hinge joint at the vertex. The instantaneous axial separation distance (which also defines the relative axial levels) between the driver member 142 and the platform 124 define the width of opening of the third crank arm and subtends an acute angle. The second arm portion 164 is intermediate the first arm portion 162 and the third arm portion 166, and is closer to the third arm portion than the first arm portion. In example embodiments, the angle of the third crank arm is less than 30% the angle of the second crank arm, for example, less than 30%, 28%, 25%, 22%, 20%, 18%, or a range or any ranges defined by selection of some or all of the aforesaid values.

[057] The linkage mechanism extends radially with respect to the stay axis to interconnect the platform 124 and the wave follower 112. The platform 124 is at a fixed axial level above the floatable body 122 during operations. The wave follower 112 is pivotable connected to the platform 124 by a crank arm, namely, the first crank arm 162, 164, which is a rigid crank arm that is pivotally movable above a pivotal joint formed on the platform 124.

[058] The linkage mechanism extends radially with respect to the stay axis to interconnect driver member 142 and the wave follower 112. The axial level of the driver member 142 above the floatable body 122 is variable during operations. The driver member 142 and the wave follower 112 is interconnected by a crank arm, namely the second crank arm 162, 166, which is a flexible crank arm having a variable crank angle. The flexible crank arm has a first pivotal joint on the driver and a second pivotal joint on the first crank arm, or more exactly on a corner of the first crank arm. The pivotal axes of the pivotal joints of the linkage mechanism are orthogonal to the stay axis.

[059] The example wave energy collector comprises a plurality of linkage mechanism to provide interconnection with a corresponding plurality of wave followers 112. Each of the linkage mechanism extends radially with respect to the stay axis and adjacent linkage mechanisms are separated by a separation angle. In example embodiments such as the present, the wave followers 112 are distributed to surround the stay and the wave followers 112 are distributed with a uniform angular separation between adjacent wave followers 112. For example, adjacent wave followers 112 of Figures 1 A and 1 B have an angular separation of 120 degrees. Where the wave followers 112 are distributed on the corners of a regular polygon, the angle of separation is determined by the angular separation of the adjacent corners of the regular polygon and adjacent link mechanism have the same angular separation without loss of generality.

[060] A dynamo 182 is mounted on the dynamo platform of the driver member 142. The dynamo comprises a rotor having a rotor shaft and a pinion gear mounted on the rotor shaft, for example, at a free end of the rotor shaft. The dynamo 182 is mounted on the dynamo platform with the rotor shaft orthogonal to the driver guide axis and with the pinion gear in coupled mechanical engagement with the teethed track 144. The driver member 142 is a movable power coupling member which is movable along the driver guide while the platform 124 is static and not movable relative to the floatable body 122 in example embodiments such as the present.

[061 ] Due to the mechanical coupled engagement between the dynamo 182 and the driver guide, the rotor shaft is rotated to generate electric power when the platform 124 moves relative to the driver guide. The rotation of the rotor is polarized in that it rotates in a first direction and generates electric current having a first polarity when the driver member 142 moves away from the platform 124 or the floatable body 122 or moves towards the free end of the teethed track 144 and that it rotates in a second direction opposite to the first direction and generates electric current having a second polarity which is opposite to the first polarity when the driver member 142 moves towards the platform 124 or the floatable body 122 or moves away from the free end of the teethed track 144. The first direction may be clockwise or anticlockwise and the second direction may be anticlockwise or clockwise, respectively. The first polarity may be positive or negative and the second polarity may be negative or positive, respectively.

[062] The dynamo may connect to a power storage device such as a rechargeable battery, a rechargeable battery bank, a capacitor, a capacitor bank, a super capacitor or a supercapacitor bank without loss of generality. The dynamo may connect to a power transmission grid or a power transmission line for exporting generated power to an external destination grid in addition or as an alternative. The dynamo may comprise a brushless generator, for example, a brushless DC generator comprising a permanent magnet rotor driven by a rotor shaft connected to the pinion gear and a coil-wound stator mounted inside a generator casing.

[063] The example wave energy collector comprises an example plurality of three wave followers 112A, 112B, 112C. Each wave follower has an associated linkage mechanism which connects the wave follower to the floatable station and the driver member 142. The plurality of wave followers 112A, 112B, 112C are mechanically connected to a corresponding plurality of linkage mechanisms. The example plurality of wave followers comprises a first wave follower 112A, a second wave follower 112B, and a third wave follower 112C. The example first wave follower 112A has an associated first linkage mechanism comprising an associated first arm portion 162A, an associated second arm portion and an associated third arm portion 166A; the example second wave follower 112B has an associated second linkage mechanism comprising an associated first arm portion 162B, an associated second arm portion and an associated third arm portion 166B; and the example third wave follower 112C has an associated third linkage mechanism comprising an associated first arm portion 162C, an associated second arm portion and an associated third arm portion 166C. Each associated arm portion has the same description as the corresponding arm portions herein. [064] The wave followers forming the plurality of wave followers are physically and mechanically connected to a common driver by a kinetic energy transformation arrangement. The example kinetic energy transformation arrangement comprises the plurality of linkage mechanisms and the linkage mechanisms are interconnected by the driver member 142, as an example of power coupling device. The connection of the wave followers to a common driver by a kinetic energy transformation arrangement comprising the plurality of linkage mechanisms means the linkage mechanisms are mechanically interconnected by the common driver. With the mechanical interconnection among the linkage mechanisms, the wave followers are to move upwards and downwards together, and optionally in synchronization.

[065] In example operations, when one, say the first wave follower 112, moves upwards, the other wave followers forming the plurality of wave followers also move upwards; when one, say the first wave follower 112, moves downwards, the other wave followers forming the plurality of wave followers also move downwards; when one, say the first wave follower 112, reaches a top dead center, the other wave followers forming the plurality of wave followers also reaches the top dead center; and when one, say the first wave follower 112, reaches a bottom dead center, the other wave followers forming the plurality of wave followers also reaches the bottom dead center. The top dead center herein corresponds to the maximum axial level of the driver member 142 and the bottom dead center herein corresponds to the minimum axial level of the driver member 142, the axial level being measured with respect to the floatable body 122.

[066] In general, the wave follower is to move up by an upward moving wave and to move downwards by gravity. The floatable body 122 may be intermediate the top dead center and the bottom dead center so that the wave follower may travel between a first position which is above the floatable body 122 and a second position which is below the floatable body 122.

[067] In example embodiments such as the present, the wave followers are distributed to surround the floatable station. More specifically, the wave followers are distributed to surround the floatable body 122. In example embodiments such as the present, the wave followers are distributed at corners of a triangle, and more specifically, corners of an equilateral triangle. In example embodiments, there may be more than three wave followers, for example, four, five, six, seven, eight, etc. and the wave followers are distributed at corners of a convex polygon, for example, corners of a regular convex polygon, optionally with the floatable station located at center of the polygon. The polygon may be a square, rectangle, pentagon, hexagon, heptagon, octagon, etc., without loss of generality.

[068] In example embodiments such as the present, the wave followers have identical specifications and the linkage mechanisms have identical specifications. The specifications include material specification, and shape, design and dimensional specifications.

[069] The linkage mechanism, the wave followers and the floatable station are arranged such that when the wave energy collector is placed on clam water, the wave energy collector is afloat, with the floatable station, or more specifically, the floatable body 122 of the floatable station partially submerged, and with the stay axis of the floatable station vertical or substantially vertical. When in the clam water condition, the wave followers are afloat at the same vertical level.

[070] In use, the wave energy collector is placed in open water such as a sea. When wind blows over a large surface of open water, waves are generated and will propagate in a direction which is referred to as wave propagation direction or propagation direction in short. The waves comprise wave crests and wave trough which are alternately distributed in the propagation direction. Each wave crest has a width and each wave trough has width which is equal to or comparable with the width of an immediately adjacent wave crest. The width of a wave crest is measured in a transversal direction which is orthogonal to the propagation direction and which is substantially parallel to the water surface. The alternately disposed wave crests and wave troughs which cooperate to define waves having characteristic ripples. When an object floats on rippling water, the object bobs up and down, while following an elliptical, a quasi-elliptical or a partially elliptical trajectory as it moves up and down. The separation distance between an immediately adjacent wave crests, or the separation distance between an immediately adjacent wave troughs, in the direction of wave propagation is the wavelength (lambda or l) of the sea wave. The vertical distance between a wave crest and an immediately adjacent wave trough defines the height or amplitude of the wave.

[071 ] The wave energy collector has a half-lambda configuration when the separation distance between the floatable station and a wave follower is equal to half-lambda. When the floatable station is at the wave trough, the wave follower can be at the wave crest, and vice versa, if the wave energy collector has a half-lambda configuration. As the height of a wave is the vertical distance between a wave crest and an adjacent wave trough, the half-lambda configuration means the wave follower will have a maximum axial displacement with respect to the wave and hence maximum energy collection possible. A larger-than half-lambda configuration provides tolerance or operation margin in orientation of the wave energy collector with respect to the wave propagation direction.

[072] In general, the separation distance between the floatable station and a wave follower may be selected to be equal to or slightly larger than half-lambda since a line joining the floatable station and the wave follower may not be aligned with or parallel to the direction of wave propagation. The separation distance, for example, measured in a direction orthogonal to the stay axis, between the floatable station and a wave follower may be selected to be equal to 0.5 lambda, 0.55 lambda, 0.6 lambda, 0.65 lambda, 0.7 lambda, 0.75 lambda, or a range or any ranges defined by selection of some or all of the aforesaid values.

[073] When the wave energy collector floats on a wave, the wave follower is moved by wave motion relative to the floatable station and to follow the wave motion. The movement of the wave follower relative to the floatable station carries kinetic energy and the kinetic energy will be converted into electrical energy by a motion conversion mechanism of a kinetic energy transformation arrangement in cooperation with the dynamo.

[074] In example embodiments, the wave energy collector of Figure 1 B has a slightly larger than half-lambda configuration, which means the separation distance between the floatable station and a wave follower is larger than half lambda. For example, the distance between the stay axis of the first wave follower 112A and the stay axis of the second wave follower 112B is approximately equal to one lambda. When a line joining the first wave follower 112A and second wave follower 112B of the wave energy collector is in or aligned with the direction of wave propagation, the floatable station 122 and the third wave follower 112C will be at the wave crest when the first and second wave followers 112A, 112B are at the wave trough. Conversely, when the floatable station 122 and the third wave follower 112C are at the wave trough, the first and second wave followers 112A, 112B will be at the wave crest.

[075] In example embodiments where the height of a wave is larger than the maximum available vertical displacement of a wave follower, when the first and second wave followers 112A, 112B are at a wave crest, the third wave follower 112C may be above the wave trough and out of water and the buoyance of the first and second wave followers 112A, 112B (optionally in cooperation with the buoyance of the floatable station) is preferably sufficient to keep the first and second wave followers 112A, 112B afloat to maintain optimal power collection and generation operations. Conversely, when the third wave follower 112C is at a wave crest, the first and second wave followers 112A, 112B may be above the wave trough and out of water, in such a case the buoyancy of the third wave follower 112C (optionally in cooperation with the buoyance of the floatable station) is preferably sufficient to keep the third wave follower 112C afloat and the first and second wave followers 112A, 112B o\A of water to maintain optimal power collection and generation operations.

[076] In order that the wave follower is to move efficiently relative or with respect to the floatable station, the floatable station, or more specifically, the floatable body of the floatable station should have an in-water moment of inertia which is significantly larger than the in-water moment of inertia of the wave followers. The in-water moment of inertia of the floatable station may be more than 3 times, 4 times, 5 times, 6 times, 7 times, 8 times, 9 times, 9 times, 10 times, that of the wave follower, or a range or any ranges defined by selection of some or all of the aforesaid values.

[077] The floatable station may have a transversal extent, measured in a direction orthogonal to the direction of the stay axis, which is significantly larger than the transversal extent of the wave follower. The transversal extent of the floatable station may be 1.5, 2, 2.5, 3, 3.5, 4 times that of the wave follower, or a range or any ranges defined by selection of some or all of the aforesaid values.

[078] The transversal clearance between the floatable station and the wave follower may be less than the transversal extent of the floatable station or less than the transversal extent of the wave follower.

[079] A wave energy collector 100A depicted in Figure 1A1 is substantially identical to that of Figure 1A, except that there is no floatable body forming the base of the floatable station. The description herein on and in relation to the wave energy collector 100 is incorporated herein by reference.

[080] A wave energy collector 200 depicted in Figure 2A is substantially identical to that of Figure 1A, except that the floatable body 222 forming the base of the floatable station has channels to permit through passage of first arm portion, and the floatable body is located above the platform 224 and below the driver 242 making it possible to enlarge the transversal dimensions of the floatable body of the floatable station without increasing the transversal dimensions of the overall wave energy collector, making possible a more compact and stable design. The description herein on and in relation to the wave energy collector 100 is incorporated herein by reference, with numerals for corresponding parts increased by 100.

[081 ] A wave energy collector 300 depicted in Figures 3A and 3B is substantially identical to that of Figures 2A and 2B, except that the floatable body 322 forming the base of the floatable station is a rectangular body. The description herein on and in relation to the wave energy collector 100 is incorporated herein by reference, with numerals for corresponding parts or components increased by 200.

[082] The power P to be generated by the wave energy collector and P = FVi 7 , where F is gravitational force due to mass of the wave follower, V is velocity and h is conversion efficiency.

[083] For a wave follower having a mass m, the force F that carries kinetic energy equals mg, where g is gravitational acceleration constant equal to about 10 (or 9.81 to be more accurate).

[084] For example, assuming the sea wave velocity V is 0.5m/s, with a power conversion efficiency h of 0.5, a power generation requirement of 300W requires a wave follower having a mass of about 120kg (~1200N). In order that the wave follower is floatable, a buoyance of at least double the weight is required so that the wave follower is only partially submerged. A double buoyance would mean that the wave follower has a volume of at least 2m, that is 240L.

[085] Where the wave follower has a cylindrical floatation body having a diameter d = 2r and a depth or axial length along the cylindrical axis Z, assuming Z = to meet a low-profile design for higher stability, the displacement volume V of the wave follower flotation body is given by the relationship v = r ² c p x l . For a cylindrical body having a displacement volume of 240L , the diameter d required is 107cm and the depth is 26.7cm.

[086] Assuming the sea wave velocity V is 0.5m/s, with a power conversion efficiency h of 0.5, where a power generation requirement of 500W is required, the wave follower required has to provide a force of 2000N. Therefore, the mass of wave follower required is around 200kg.

[087] The wave energy collector may comprise an on-board power storage device such as a rechargeable battery or a capacitor for storing collected waver energy and charging management device to manage charging of the power storage device. The on-board power storage device may be contained in a water-tight compartment inside the floatable station as a convenient example.

[088] The term“wave” herein includes wind waves which are waves generated by wind passing over a large water surface which extends over a large open area, and includes sea waves, ocean waves, lake waves, reservoir waves, or other waves that has rippling or ripple characteristics, for example, ripples along the direction of wave propagation.

[089] While the disclosure has been made with example embodiments, the embodiments are non- restrictive examples.