The invention pertains to the field of power engineering, in particular, to devices for converting the energy of sea waves into electrical energy.

The use of sea wave energy is a rapidly developing trend in the use of renewable energy sources, which should reduce the consumption of already exhaustible organic fuels, environmental pollution and limit the construction of nuclear power plants, the safety of which, after the major accidents in Chernobyl and Japan, is left in serious doubt today.

There are currently many different ideas and patents regarding the use of sea wave energy. The profitability of installations using these well-known patents is currently much lower than the profitability of thermal power plants and hydroelectric power plants.

This is due to the rather high cost of the devices intended for converting the energy of sea waves and the uneven intensity of the waves over time.

Moreover, when calculating the strength of a wave power plant, the possibility of generating a wave in stormy conditions should be taken into account, which increases its cost.

The uneven power produced by the wave energy plant, caused by the uneven intensity of the waves over time, is partially compensated by connecting it to the power system, which has the ability to regulate the power supplied by its electric plants with water reservoirs in power plants and partially change the load on a thermal power plant. In order for devices converting sea wave energy into electricity to be able to compete with traditional sources of electricity, it is first necessary to reduce their installation and operation costs, as well as to increase their stability during high intensity storm waves. In the depth of the water, the waves decrease rapidly, and below the surface, at a distance of half the wavelength, they practically disappear. When approaching the shore, the wave crest becomes parallel to the shoreline. Wave height first increases with decreasing sea depth, and then begins to decrease with decreasing depth for a distance of less than half a wavelength.

When the pontoon is submerged, it is acted upon by a buoyant force Fs( _K r)=h(M)*S(M ² )*p(kg/M ³ ) where h is the magnitude of the pontoon's immersion in the water.

S is the cross-section of the pontoon, P is the specific gravity of the water.

At the same time, the high-speed jet of the lifting water stream acts on the bottom of the pontoon.

The evaluation shows that the buoyancy force (for example, for a stationary pontoon) is much greater than the force of the high-velocity surrounding flow of rising water.

The total force acting on the pontoon can be quite large. At the same time, for efficient conversion of wave energy, water rising velocities are relatively low.

In order to obtain electrical energy from the wave, it is first necessary to convert the wave energy into the rotational energy of a shaft connected to a generator (other methods of vibration are ineffective). However, at low shaft revolutions, the cost of the generator is high. At high power and low speed, the use of mechanical gearboxes is inefficient and expensive.

Instead of a gearbox, a pulley-block is used in some technical solutions.

The simplicity of the pulley-block structure and the low cost of its parts (mainly the rollers) make the conversion to electrical energy quite cheap.

For example, the power plant disclosed in German patent application DE10006881 (Al) is known. The device uses a pulley-block consisting of two fixed rollers and a free roller. The device also includes a relatively large roller, which is located next to the first fixed roller and is used only for the downward movement of the load. These rollers are connected to the loads through a rope or chain. Also known is the wave energy plant described in the Bulgarian patent application BG1079 (Ul). The plant consists of a generator connected to a shaft containing modules connected in sequence, wherein each module consists of a shaking wheel mounted on a shaft and a pulley on which a rope is wound, one end of which is connected to the working pulley through an n-fold lifting pulley-block, and the other end is connected to a counterweight.

Despite the fact that a pulley-block is used in the above devices, the increase in the speed of the rope (compared to the speed of lifting the pontoon) is insufficient. Moreover, the load, which also acts as a floating anchor, has large losses during movement and reduces the amplitude of the oscillating process, and the rope’s engagement with the roller is insufficient and it may slip during operation.

In addition, it is not possible to place and operate the plant near the coastline, which makes its operation more expensive.

The technical effect of the present invention is increase in the efficiency of the plant and expanding its functional capabilities.

In order to achieve the above-mentioned technical effect, the present invention proposes a wave energy plant, which comprises: a floating member designed to move vertically upward and downward with the movement of the wave; a main pulley-block that is attached to a floating memeber and is intended to increase the speed of the cable, comprising a plurality of upper and lower rollers for passing the cable thereon, which are disposed on the upper and lower roller holders, respectively; a load that is connected to the floating member through the cables and the main pulleyblock, and that is intended to be placed stationary on the seabed and to load the floating member;

At least one electric generator with a shaft that is connected by pulleys and cable to the main pulley-block and is intended to convert the kinetic energy of the movement of the floating member into electrical energy; an additional pulley-block comprising a plurality of upper and lower rollers for passing the cable thereon, rigidly connected to the main pulley-block and designed to retard the movement of the additional load connected to the pulley-block by means of a cable; an additional load that is connected to the additional pulley-block by means of a cable and is intended to sink into the water depth and to tension the cable passing through the rollers of the main pulley-block during the movement of the floating member.

According to a preferred aspect of the embodiment of the invention, the floating member is made in the form of a pontoon.

According to a preferred embodiment of the invention, the pontoon comprises air and water itake and discharge means.

According to a preferred embodiment of the invention, the main pulley-block comprises two or more pulleys mounted on a single shaft.

According to a preferred embodiment of the invention, the plant uses freewheel clutches connected to said pulleys to transfer rotary motion through them to electric generators during forward and reverse motions of the main pulley-block.

According to one aspect of the embodiment of the present invention, a system of wave energy plants is provided that comprises a plurality of electrically connected wave energy plants. The invention is explained with reference to the appended figures, wherein

Fig. 1 shows a schematic representation of the structure of the wave energy plant according to the present invention;

Fig. 2 shows a schematic representation of the pontoon structure of the wave energy plant according to the present invention;

Fig. 3 shows a hydraulic valve designed to fill a pontoon with water, a motor with a gearbox and a shaft designed to control the hydraulic valve, a valve with its own motor and gearbox designed to release air from the pontoon, a control valve designed to enter air into the pontoon from a common hose;

Fig. 4 shows a system consisting of a plurality of wave energy plants located in the sea.

The reference numerals of the same elements are the same across all figures.

Detailed description

Fig. 1 shows a schematic representation of the structure of the wave energy plant according to the present invention.

The plant comprises a pontoon 1 that is connected to a load 6 by means of two high strength cables 7 through the main pulley-block 3. Pulleys-blocks 3 and 4 have a common cable 8 passing through one or more pulleys 15. The pulleys 15 are mounted on a shaft connected to shafts 21 of two electric generators 11, 12 through free release clutches, i.e. through freewheel clutches 20, which rotate the electric generators 11, 12 in different directions. The output end of the cable 8 then descends onto the rollers of the second auxiliary pulley-block 4, on which the load 5 is suspended. The load 5 has the capability of moving along the cables 7, for which purposes the corresponding holes are made therein. The load 5 is designed to tension the common cable 8 and to engage the latter well to the pulleys. In addition, it provides reverse motion once the pontoon is raised.

The main pulley-block 3 and the auxiliary pulley-block 4 comprise upper and lower roller holder 22, for example in the form of a plate. The lower roller holder 22 of the main pulleyblock 3 and the upper roller holder 22 of the additional pulley-block 4 are rigidly attached to each other so as to form a stationary frame 23. The said stationary frame 23, through a cable that is tensioned by the pontoon 1, is connected to the main load 6. The upper roller holder 22 of the main pulley-block 3 is rigidly connected to the pontoon 1. The hoi det 22 of the lower rollers of the additional pulley block 4 is rigidly connected to the additional load 5. The moving elements in the structure of the entire plant are: panton 1, common cable 8 of the first and second pulley-blocks 3 and 4, and the additional load 5.

Both pulley-blocks have a common cable, which passes from the main pulley-block to the other pulley-block through one or more pulleys.

The structure includes a roller 22, which plays the role of an intermediate element to pass the cable from one pulley to another and to strengthen the engagement of the cable with the pulleys.

The auxiliary pulley-block 4 is required to retard the movement of the load 5, which enables the wave energy plant to operate at a relatively shallow depth, that is, closer to the shore.

The main pulley-block 3 is intended to increase the speed of movement of the common cable 8 when lifting the pontoon, the value of which depends on the number of rollers. In the plant, the speed of the common cable 8 increases 8-10 times. Accordingly, the tension force of the cable decreases, which makes it possible to use relatively small diameter pulleys 15 and the shaft on which they are mouted. Owing to such a construction, it is clear that the rotary movement transferred from the pulleys to the electric generators will have a high number of revolutions per unit of time, as a result of which it is possible to reduce the volume and cost of the generators.

Electric generators 11, 12 are mainly made in the form of induction generators, which can work in a wide range of revolutions.

It should be noted that during operation, the cable is partially wetted by water, and in order to maintain the cable in good engagement, it must have a certain tensile force F2 after passing over the pulley. In the present plant, this force is created by the auxiliary pulley -block 4 and the load 5.

The permissible value of the mentioned force Fl, which keeps the cable in engagement with the pulleys, is determined by the equation: where Kr _P - is the coefficient of friction between the cable material and the pulley material, oc- the total angle of passage of all pulleys by the cable.

With a small coefficient of friction (semi-dry friction), the allowable value Fi can be increased by increasing the number of pulleys on the drive shaft. An intermediate roller or rollers 21, whose axis is parallel to the axis of the pontoon, is used to move from one spulley to another in the main pulley-block 3.

The plant operates as follows.

As the pontoon is lifted by the wave, the main pulley-block 3 is tensioned and pulls the common cable 8 between its upper and lower rollers shown in the figure. At this time, the common cable 8 rotates the pulleys in one direction, and the rotational moment is transferred to the electric generator 11 through one of the freewheel clutches. At the same time, the load 5 is lifted through the pulley-block 4.

When the wave descends, the tension force on the pulley-block 3 weakens and the load 5 through the pulley-block 4 tensions the common cable 8 in the reverse direction, as a result of which the rotational moment is transferred to the generator 12 through the second freewheel clutch.

The load 5 produces a constant tension, and the force acting on the pontoon lifting depends on the intensity of the waves, which is taken into account in the calculation of the power and excitation currents of the induction generators.

The evaluation shows that the buoyancy force (for example, for a stationary pontoon) is much greater than the force of the high-velocity surrounding flow of rising water.

The total force acting on the pontoon can be quite large. At the same time, for efficient conversion of wave energy, water raising velocities are relatively low. According to practical studies, the power extracted from the wave by the pontoon strongly depends on the pontoon's own frequency setting and the frequency of the incoming wave. All this is taken into account in designing the present wave energy plant pontoon, which is shown in fig. 2.

For this, the pontoon has a cylindrical shape and is made inflatable. It is preferably made of a strong rubber-like fabric. A hole is made in the middle part of the pontoon, in which the groove 10 is inserted. The groove with both ends clamps the edges of the fabric to the hole and the space inside the pontoon is sealed. A housing 13 is hermetically mounted in the upper part of the groove, in which electric generators are placed in the compartments made therein. The shafts of electric generators are connected to the common shaft by pulleys. From the pulleys to the pulley-blocks, the cables descend in the groove. What can also be seen in the figure is the shaft of the generator 21, the freewheel clutch 20, the bearing 17, the packing seal 16 for sealing the compartments of the generators. On the housing 13, a seat body 18 is mounted for fixing the cable 14, which is intended for connecting different wave energy plants to each other and to the central pontoon 32 (see Fig. 4 The central pontoon is the element where the ends of the electric cables of all the plants of the system meet, so that it can be connected to the corresponding power station on the coast. Two single-phase power cables 23, 24 are hung on the cable 14, through which the direct current generated by the electric generators is transmitted. Through hose (rubber) 25, air is supplied to the pontoons under pressure to inflate them. Said cables and air hose are collected on the central pontoon 32, and then pass to the substation 33 by hanging in the air or passing through the seabed.. Substation 33 is equipped with a means of converting direct voltage into alternating voltage of industrial frequency, for example, with a thyristor inventor, from which centralized control of the operation mode of various wave energy plants is carried out.

Fig. 3 shows a hydraulic valve 27, which is designed to fill the pontoon with water, a motor with a gearbox 28 and a shaft designed to drive the hydraulic valve, a valve 29 with its motor and a gearbox 30, that is intended to release air from the pontoon, a controlable valve 31 that is intended to admit air into the pontoon from a common hose.

Hydraulic valve 27 is designed to let water into the pontoon and regulate its mass, through which the oscillating process is set according to the frequency of the waves. Water intake is performed by opening the hydraulic valve 27 and releasing air through valve 29, and water release is performed by pressurizing the pontoon through valve 31. In conditions of extreme sea turbulence, for which the strength of the pontoon is not calculated, air is released from the latter and its cross-section decreases. Due to this, the pontoon takes a shape that is easier to get around with water. With such a construction, it is also possible to completely submerge the pontoon in water (in this case, all electrical wires must be properly sealed). All equipment can be controlled centrally from a substation located on shore. As mentioned above, inductive generators, preferably inductive disk generators, are used to convert mechanical energy into electrical energy, at the output of which a constant voltage is obtained, which makes it possible to connect a number of generators in parallel to each other through cables 23, 24. Inductor generators can operate at different rotation numbers and maintain voltage levels through excitation current regulation, which can also be done centrally from a shore-based substation.

The performance of all electrical components of the system is obvious and known to those skilled in the art and is not discussed in detail in this description. The shape of the inflatable pontoon during its manufacture can be secured by tensioners 25 (see Fig. 3).

Fig. 4 shows a plurality of offshore wave energy plants connected to each other, to a central pontoon 32 and to an onshore substation 33. The central pontoon 32 is connected to the substation 33 via a cable hanger 34, which in an alternative embodiment may be a cable laid on the seabed.