A tidal energy power generation system

Abstract

The present invention provides a tidal energy power generation system, the structure of which includes a cavity (1), an A gas pipeline (2), a pressure accumulator, and an expansion machine generator set (6); wherein, the cavity (1) is communicated with one end of the A gas pipeline (2), the other end of the A gas pipeline (2) is communicated with the pressure accumulator, and the pressure accumulator is connected to the expansion machine generator set (6) through a B gas pipeline. Advantage: The present invention can generate tidal energy without necessarily building an upper reservoir or a lower reservoir.

Description

Technical Field

[0001] The present invention relates to a tidal energy power generation system, belonging to the technical field of tidal energy power generation. Background Art

[0002] The development and utilization of tidal energy are still in the stage of exploration and research all over the world. The current mainstream technical solution is to build an upper reservoir. When the tide rises, the sea water is introduced into the upper reservoir. In some technical solutions, the water flow entering the reservoir during high tide is used to generate electricity once through a water turbine generator set, while some technical solutions do not have this process; when the tide ebbs, the sea water in the upper reservoir is released, and the kinetic energy and potential energy of the water are used to drive the water turbine to drive the generator set to generate electricity; there are also technical solutions to build a lower reservoir on this basis to improve the utilization efficiency of tidal energy, but the power generation principle remains unchanged.

[0003] The following are the main problems existing in the use of tidal energy for power generation in the prior art:

[0004] 1) There is a high requirement for tidal head. Generally, it is considered that the tidal head with economic development value should be more than 3 meters, which excludes many coastlines, and low tidal head tides cannot be developed;

[0005] 2) There is a high requirement for terrain and topography. The current solutions require suitable places to build the upper reservoir, and some technical solutions also require suitable places to build the lower reservoir at the same time. The construction of the reservoir has high costs on the one hand and requires good geological conditions on the other hand, which affects the selectivity of the buildable locations;

[0006] 3) Since a reservoir needs to be built, it will occupy a large amount of coastline and adjacent areas. And the reservoir is often used for aquaculture. When aquaculture is carried out in the reservoir, the aquaculture will occupy part of the reservoir capacity, and the occupied reservoir capacity cannot be used for power generation by the existing tidal energy power generation technology, which has a great impact on the local economy and ecological environment;

[0007] 4) The change in the water level difference formed by high tide and low tide is a waveform curve similar to a waveform, resulting in unstable kinetic energy and potential energy contained in the water flow, and the water level change of each tide is also large, thus resulting in unstable power generation capacity and becoming an unstable power source that is not popular with the power grid;

[0008] 5) Also due to the non-constancy of the water flow, the water turbine cannot maintain the best design working state, resulting in low energy utilization efficiency;

[0009] 6) The water turbine and the valve controlling the sea water flow direction work in the sea water for a long time, and the sea water has great corrosiveness to metal components. Therefore, in the existing technical solutions, the frequent equipment anti-corrosion constitutes a large part of the operating cost, and during the anti-corrosion operation, the unit cannot be put into operation, reducing the unit utilization efficiency and the return on investment;

[0010] 7) The equipment and the reservoir area also need to regularly carry out the work of removing marine organisms. Especially the marine organisms attached to the blades of the water turbine will seriously damage the blade shape, thus reducing the equipment efficiency and at the same time reducing the utilization time of the unit.

[0011] 8) Since there is a corresponding relationship between the construction of the reservoir and the unit capacity, when the project is completed, the power generation capacity of the project is restricted, and it is extremely difficult to carry out further expansion. Summary of the Invention

[0012] The present invention provides a tidal energy power generation system, aiming to provide a system that can generate tidal energy without completely relying on the construction of an upper reservoir or a lower reservoir.

[0013] Technical solution of the present invention: A tidal energy power generation system, whose structure includes a cavity 1, an A gas pipeline 2, a pressure tank, and an expansion machine generator set 6. Among them, one end of the cavity 1 is communicated with one end of the A gas pipeline 2, the other end of the A gas pipeline 2 is communicated with the pressure tank, and the pressure tank is connected with the expansion machine generator set 6 through a B gas pipeline.

[0014] Advantages of the present invention:

[0015] 1) The present invention can generate tidal energy without having to build an upper reservoir or a lower reservoir.

[0016] 2) The present invention does not affect local mariculture, etc. Even it can be combined with breakwaters, coastal dikes, docks, etc., without occupying additional coastline, increasing the utilization level of tidal energy.

[0017] 3) Except for the cavity 1 part, other components of the present invention can be located on land or erected above the highest water level line, so that maintenance and repair can be conveniently carried out. The cost and time-consuming of maintenance and repair are also much lower than the current technical solutions, providing great support for improving the economy of the whole solution.

[0018] 4) The present invention can also be installed on existing tidal energy power generation projects, combined with existing tidal energy power generation technologies, to further improve the economy of existing tidal energy power generation projects.

[0019] 5) The present invention realizes safe, reliable, energy-saving, environment-friendly, flexible and efficient tidal energy power generation at a low cost. Description of the Drawings

[0020] Attached Figure 1 is a schematic structural diagram of the tidal energy power generation system of the present invention.

[0021] Attached Figure 2 is a schematic structural diagram of the tidal energy power generation system when there is more than one cavity 1.

[0022] Appendix Figure 3 is a schematic structural diagram of a tidal energy power generation system when the pneumatic tank only has the gas storage tank 3 and no negative pressure tank 5.

[0023] Appendix Figure 4 is a schematic structural diagram of a tidal energy power generation system when the pneumatic tank only has the negative pressure tank 5 and no gas storage tank 3.

[0024] In the attached drawings, 1 is the cavity, 2 is the A gas pipeline, 2-1 is the pressure pipeline, 2-2 is the suction pipeline, 3 is the gas storage tank, 4-1 is the intake pipeline, 4-2 is the exhaust pipeline, 5 is the negative pressure tank, 6 is the expander generator set, 7 is the A check valve, 8 is the B check valve, 9 is the intake valve, 10 is the exhaust valve, 11 is the valve, 12 is the upper port of the cavity 1, 13 is the lower port of the cavity 1, 14 is the C check valve, 15 is the D check valve, and 16 is the ventilation valve. Specific embodiments

[0025] A tidal energy power generation system, whose structure includes a cavity 1, an A gas pipeline 2, a pneumatic tank, and an expander generator set 6; wherein, the cavity 1 is communicated with one end of the A gas pipeline 2, the other end of the A gas pipeline 2 is communicated with the pneumatic tank, and the pneumatic tank is connected with the expander generator set 6 through a B gas pipeline.

[0026] The cavity 1 has an upper port 12 and a lower port 13; except for the upper port 12 and the lower port 13, other parts of the cavity 1 are of a closed structure; preferably, the upper port of the cavity 1 is communicated with one end of the A gas pipeline 2; during operation, the lower port of the cavity 1 is located below the water surface.

[0027] The material of the cavity 1 is preferably any one of concrete, rubber and plastic materials, and metal; specifically, the material of the cavity 1 can be selected according to factors such as the scale of the tidal energy power generation system, considering concrete, rubber and plastic materials, metal and other materials that can withstand a certain pressure and are resistant to seawater corrosion; the cavity 1 can also be further equipped with settings for preventing the attachment of marine organisms or facilitating the cleaning of marine organisms.

[0028] The pressure vessel is an air storage tank 3 or a negative pressure tank 5; when the pressure vessel is the air storage tank 3, there is a one-way valve 7 on the A gas pipeline 2 between the cavity 1 and the air storage tank 3. During high tide, the rising sea water compresses the gas medium in the cavity 1, and the gas medium is introduced into the air storage tank 3 through the A gas pipeline 2 to form pressurized gas in the air storage tank 3; the gas medium in the cavity 1 is preferably air; when the pressure vessel is the negative pressure tank 5, there is a one-way valve 8 on the A gas pipeline 2 between the cavity 1 and the air storage tank 3. During low tide, due to the drop in the sea level, the water level in the cavity 1 will also drop synchronously, thus forming a negative pressure area in the upper part of the cavity 1 to suck the gas medium in the negative pressure tank 5, so as to form a negative pressure area lower than the atmospheric pressure in the negative pressure tank 5 until the low tide reaches the lowest water level. The gas medium in the negative pressure tank 5 is also preferably air; the volume of the cavity 1 is preferably larger than the volume of the air storage tank 3 or the negative pressure tank 5; the size of the air storage tank 3 or the negative pressure tank 5 should be calculated and determined according to the available tidal energy at the project site. The material of the air storage tank 3 or the negative pressure tank 5 is preferably a material that can withstand a certain pressure or negative pressure and can withstand the corrosion of salt spray blown by the general sea breeze; the material of the air storage tank 3 or the negative pressure tank 5 is preferably carbon steel or concrete casting, and paint is applied on the surface for anti-corrosion.

[0029] The pressure vessel includes an air storage tank 3 and a negative pressure tank 5. The A gas pipeline 2 includes a pressure gas pipeline 2-1 and a suction gas pipeline 2-2; one end of the A gas pipeline 2 is connected to the cavity 1 and then divided into two branches, namely the pressure gas pipeline 2-1 and the suction gas pipeline 2-2. The cavity 1 is connected to the air storage tank 3 through the pressure gas pipeline 2-1 and to the negative pressure tank 5 through the suction gas pipeline 2-2. A one-way valve 7 is connected in series on the pressure gas pipeline 2-1, and a one-way valve 8 is connected in series on the suction gas pipeline 2-2; the lower port of the cavity 1 is located below the water surface; during high tide, due to the rising sea level, the sea water enters the cavity 1 through the lower port of the cavity 1 and the water level rises, thus pressing the gas medium inside the cavity 1. At this time, the one-way valve 7 on the pressure gas pipeline 2-1 opens, and the one-way valve 8 on the suction gas pipeline 2-2 closes, so that the gas medium enters the air storage tank 3 unidirectionally along the pressure gas pipeline 2-1 through the one-way valve of the one-way valve 7 until the high tide reaches the highest water level, forming compressed gas with a certain pressure in the air storage tank 3, converting the potential energy of the tide into the potential energy of the compressed gas and storing it; during low tide, due to the drop in the sea level, the water level in the cavity 1 will also drop synchronously, thus forming a negative pressure area in the upper part of the cavity 1. At this time, the one-way valve 7 on the pressure gas pipeline 2-1 closes, and the one-way valve 8 on the suction gas pipeline 2-2 opens, sucking the gas medium in the negative pressure tank 5, so as to form a negative pressure area lower than the atmospheric pressure in the negative pressure tank 5 until the low tide reaches the lowest water level; the volume of the cavity 1 is preferably larger than the sum of the volumes of the air storage tank 3 and the negative pressure tank 5; the gas medium is preferably air.

[0030] The expander generator set 6 includes an expander and a generator; wherein the expander is preferably a turbine expander or a piston expander; the expander has an air inlet and an air outlet, the air inlet of the expander is connected to the gas storage tank 3, and the air outlet of the expander is connected to the negative pressure tank 5; when working, pressurized gas is introduced into the expander, and the air outlet of the expander is connected to the negative pressure tank 5, and the gas will quickly enter the negative pressure tank 5 from the gas storage tank 3 through the expander, thereby driving the expander to do work and driving the generator connected to the expander to generate electricity.

[0031] The B gas pipeline includes an air inlet pipeline 4-1 and an air outlet pipeline 4-2. The air inlet of the expander is connected to the gas storage tank 3 via the air inlet pipeline 4-1, and the air outlet of the expander is connected to the negative pressure tank 5 via the air outlet pipeline 4-2. An air inlet valve 9 is connected in series to the air inlet pipeline 4-1, and an exhaust valve 10 is connected in series to the air outlet pipeline 4-2. The material of the expander is preferably a material that can withstand salt spray corrosion caused by general sea breeze. The material of the expander is further preferably carbon steel or aluminum alloy, and the surface of the expander is preferably painted to enhance corrosion protection.

[0032] When the present invention is working, after the gas storage tank 3 and the negative pressure tank 5 establish pressure and vacuum respectively, the connection between the gas storage tank 3, the negative pressure tank 5 and the expander generator set 6 can be opened by opening the air inlet valve 9 and the exhaust valve 10, and the compressed gas in the gas storage tank 3 enters the expander generator set 6 to start working and generating electricity. At the same time, the vacuum negative pressure established by the negative pressure tank 5 helps the expander generator set 6 to improve the working power and efficiency. The pressure in the gas storage tank 3 and the vacuum degree in the negative pressure tank 5 gradually decrease until they are lower than the working range of the expander generator set 6, completing this round of work. The above process is repeatedly circulated together with the ebb and flow of tides to form positive pressure areas and negative pressure areas in the gas storage tank 3 and the negative pressure tank 5 respectively, wherein the gas storage tank 3 and the negative pressure tank 5 can be arranged as a single or multiple according to the project characteristics and operation.

[0033] The A gas pipeline 2 is a connecting pipeline, and a desalination device can be further connected in series to the A gas pipeline 2; the material of the A gas pipeline 2 is preferably a material that can withstand a certain pressure and can withstand seawater salt spray corrosion; further, the material of the A gas pipeline 2 is preferably carbon steel or rubber plastic or resin material; further, the A gas pipeline 2 is lined with anti-corrosion material and painted on the outside.

[0034] The exhaust pipe 2-2 is required to be able to withstand a certain negative pressure; the material of the exhaust pipe 2-2 is preferably carbon steel or rubber plastic or resin material; further, the exhaust pipe 2-2 is lined with anti-corrosion material and painted on the outside.

[0035] When the tidal energy power generation system of the present invention is actually working, except that the lower port 13 of the cavity 1 is located below the water surface, other components are preferably arranged on land or overhead above the highest water level line, thereby avoiding seawater corrosion and attachment of marine organisms. Compared with the existing solutions, the material requirements for seawater corrosion prevention and marine organism attachment prevention of the equipment are significantly reduced, thus reducing the cost. During operation, a large amount of anti-corrosion cost and marine organism removal cost required in the existing technical solutions are also saved, and at the same time, the downtime for treatment is reduced, greatly improving the economic benefits.

[0036] The present invention can adapt to various tidal differences, and at the same time has less requirements for terrain. It can even be buried under the beach without affecting the development of marine aquaculture or tourism. Since only the lower port 13 of the cavity 1 needs to be immersed under the water surface, the rest does not need to be immersed under the water surface, and there are no moving parts of the tidal energy power generation system of the present invention immersed under the water surface, so the workload of relevant anti-corrosion and marine organism removal is greatly reduced compared with the existing technology. Except for the lower port 13 of the cavity 1, other various equipment and facilities in the present invention can be arranged in the open air and conventional workshops, and the cost of construction and maintenance is much lower than that of the facilities and equipment that need to work under the water surface in the existing technology. Moreover, the present invention has a long working life, is easy to maintain, and can be in the best and most efficient working state for a long time.

[0037] When the tidal energy power generation system of the present invention is actually working, the cavity 1 is arranged on the coast with tidal energy development value. For economic considerations, the bottom of the cavity 1 is preferably located below the lowest water level line at low tide, and for the convenience of maintenance, the top of the cavity 1 is preferably located above the highest water level line at high tide.

[0038] In specific implementation, the cavity 1 is a single one or a collection of two or more. When the number of cavities 1 ≥ 2, the tops of the respective cavities 1 can be interconnected by means of pipelines, etc. A valve 11 is provided at the top of the upper port of each cavity 1 to guide the flow direction of the gas medium during high tide and low tide. When the number of cavities 1 is greater than 1, when maintenance and cleaning work are carried out on one of the cavities 1, the valve 11 at the top of the upper port of the corresponding cavity 1 can be closed separately without affecting the continued operation of other cavities 1 and the entire expander generator set 6. The cavity 1 can be further provided with a maintenance opening to facilitate maintenance and marine organism removal work.

[0039] In implementation, since the number of cavities 1 can be greater than 1, the working pressure and vacuum can be continuously established in the gas storage tank 3 and the negative pressure tank 5 according to the power generation load plan, and several gas storage tanks 3 and negative pressure tanks 5 can also be constructed respectively, so as to provide compressed gas and vacuum degree for the expander generator set 6 to work throughout the day.

[0040] The tidal energy power generation system of the present invention can also be simplified. In the simplified solution, the gas storage tank 3 or the negative pressure tank 5 is cancelled, and only one of the gas storage tank 3 and the negative pressure tank 5 is retained. When only one of the gas storage tank 3 and the negative pressure tank 5 is retained, only the working power and efficiency of the entire tidal energy power generation system will be reduced, and the basic function realization of the entire tidal energy power generation system will not be affected.

[0041] When the pressure gas tank only has the gas storage tank 3 and no negative pressure tank 5, the A gas pipeline 2 is a pressure gas pipeline 2-1. A C check valve 14 is installed on the side wall of the pressure gas pipeline 2-1. An A check valve 7 is connected in series on the pressure gas pipeline 2-1. The C check valve 14 is located between the upper port 12 of the cavity 1 and the A check valve 7. The C check valve 14 is located above the water surface. The B gas pipeline includes an intake pipeline 4-1 and an exhaust pipeline 4-2. The intake port of the expander is connected to the gas storage tank 3 through the intake pipeline 4-1. An intake valve 9 is connected in series on the intake pipeline 4-1. The exhaust port of the expander is connected to the atmosphere through the exhaust pipeline 4-2. An exhaust valve 10 is connected in series on the exhaust pipeline 4-2. Whether the exhaust port of the expander is communicated with the atmosphere is controlled by opening or closing the exhaust valve 10. During high tide, due to the rising sea level, seawater enters the cavity 1 through the lower port 13 of the cavity 1 and the water level rises, thereby compressing the gas medium inside the cavity 1. At this time, the A check valve 7 on the pressure gas pipeline 2-1 opens, and the C check valve 14 on the side wall of the pressure gas pipeline 2-1 closes, so that the gas medium enters the gas storage tank 3 unidirectionally along the pressure gas pipeline 2-1 through the one-way valve of the A check valve 7 until the high tide reaches the highest water level, and compressed gas with a certain pressure is formed in the gas storage tank 3, converting the potential energy of the tide into the potential energy of the compressed gas and storing it. During low tide, the water level in the cavity 1 drops to form a vacuum. At this time, the A check valve 7 on the pressure gas pipeline 2-1 closes, and the C check valve 14 on the side wall of the pressure gas pipeline 2-1 opens, and external air enters the cavity 1 for use during the next high tide.

[0042] When the pressure accumulator only has a negative pressure tank 5 and no gas storage tank 3, the A gas pipeline 2 is a suction pipeline 2-2. A D check valve 15 is installed on the side wall of the suction pipeline 2-2. A B check valve 8 is connected in series on the suction pipeline 2-2. The D check valve 15 is located between the upper port 12 of the cavity 1 and the B check valve 8. The D check valve 15 is located above the water surface. The B gas pipeline includes an intake pipeline 4-1 and an exhaust pipeline 4-2. The intake port of the expander is connected to the atmosphere through the intake pipeline 4-1. An intake valve 9 is connected in series on the intake pipeline 4-1. The exhaust port of the expander is connected to the negative pressure tank 5 through the exhaust pipeline 4-2. An exhaust valve 10 is connected in series on the exhaust pipeline 4-2. Whether the intake port of the expander is communicated with the atmosphere is controlled by opening or closing the intake valve 9. During ebb tide, due to the drop of the sea level, the water level in the cavity 1 drops to form a vacuum. At this time, the B check valve 8 opens, and the gas medium in the negative pressure tank 5 enters the cavity 1 unidirectionally along the suction pipeline 2-2 through the one-way valve of the B check valve 8, so as to form a negative pressure area lower than the atmospheric pressure in the negative pressure tank 5. During flood tide, the sea water enters the cavity 1 through the lower port 13 of the cavity 1 and the water level rises, thus pressing the gas medium in the upper part of the cavity 1. At this time, the B check valve 8 on the suction pipeline 2-2 closes, and the D check valve 15 on the side wall of the suction pipeline 2-2 opens to discharge the redundant gas medium in the cavity 1, so that the air pressure in the cavity 1 is maintained at the same level as the external atmospheric pressure, which is convenient for the air pressure in the cavity 1 to decrease during the next ebb tide to continue sucking the gas medium in the negative pressure tank 5.

[0043] When the pressure accumulator includes both a gas storage tank 3 and a negative pressure tank 5, a ventilation valve 16 can be further installed on the side wall of the cavity 1 or the side wall of the A gas pipeline 2. Because when the pressure accumulator includes both a gas storage tank 3 and a negative pressure tank 5, although the gas circuit of the whole tidal energy power generation system is closed and the internal gas medium is recycled, and there is already gas medium in the cavity 1 for use when it is built, considering that there will still be a certain amount of gas medium loss after long-term use, a ventilation valve 16 can be installed on the side wall of the cavity 1 or the side wall of the A gas pipeline 2, and the ventilation valve 16 can be opened as needed to supplement the internal gas medium of the whole tidal energy power generation system. However, even without the ventilation valve 16, it still does not affect the use and realization of the basic functions of the whole tidal energy power generation system. The gas medium can be supplemented from other positions when the whole tidal energy power generation system is not working. For example, the gas medium can be supplemented through connecting other external pipelines from the lower port 13 of the cavity 1. The ventilation valve 16 is preferably installed on the side wall of the pressure pipeline 2-1 or the side wall of the suction pipeline 2-2.

[0044] In the present invention, since there are no moving parts in the cavity 1, its internal space and structure are extremely simple, making it very convenient to carry out anti-corrosion and removal of marine organisms work. The time and cost for maintenance are also much lower than those of the existing technical solutions. At the same time, if the number of cavities 1 is greater than one, the valves at the upper ports of the corresponding cavities 1 can be closed, so as not to affect the continued operation of other cavities 1 during maintenance and repair.

[0045] In the present invention, the cavity 1 can be selected to occupy the coast or backfill and restore the ground surface according to project conditions, without affecting local mariculture, etc. Even it can be combined with breakwaters, coastal dikes, docks, etc., without additionally occupying the coastline. Except for the cavity 1, other components can be set at appropriate locations according to local conditions, including being built on the cavity 1, and the flexibility is significantly higher than that of the existing technical solutions.

[0046] The application of the present invention can also be gradually implemented in a unitized manner. Each tidal energy power generation system is a unit unit. By establishing several unit units, the expandability is far beyond that of the existing technical solutions.

[0047] The present invention can utilize the tidal energy at low tide levels. As long as cavities 1 with sufficient volume are set according to needs, the tidal energy can be developed and utilized, increasing the utilization level of tidal energy, and the scale can be large or small. In the whole technical solution, each component and technology meet the current scientific and technological development level, and the requirements for materials are also much lower than those of the existing technical solutions, which is of great help to reducing the project cost and the later operation and maintenance costs.

Claims

1. A tidal energy power generation system, characterized in that It includes a cavity (1), an A gas pipeline (2), a pressure tank, and an expansion turbine generator set (6); wherein, the cavity (1) is communicated with one end of the A gas pipeline (2), the other end of the A gas pipeline (2) is communicated with the pressure tank, and the pressure tank is connected with the expansion turbine generator set (6) through a B gas pipeline; the pressure tank includes a gas storage tank (3) and a negative pressure tank (5), and the A gas pipeline (2) includes a pressure gas pipeline (2-1) and a suction gas pipeline (2-2); one end of the A gas pipeline (2) is communicated with the cavity (1) and then divided into two branches, namely the pressure gas pipeline (2-1) and the suction gas pipeline (2-2). The cavity (1) is communicated with the gas storage tank (3) through the pressure gas pipeline (2-1) and with the negative pressure tank (5) through the suction gas pipeline (2-2). An A one-way valve (7) is connected in series on the pressure gas pipeline (2-1), and a B one-way valve (8) is connected in series on the suction gas pipeline (2-2); the expansion turbine generator set (6) includes an expansion turbine and a generator; the expansion turbine has an air inlet and an air outlet. The air inlet of the expansion turbine is communicated with the gas storage tank (3), and the air outlet of the expansion turbine is communicated with the negative pressure tank (5); the B gas pipeline includes an air inlet pipeline (4-1) and an air outlet pipeline (4-2). The air inlet of the expansion turbine is connected with the gas storage tank (3) through the air inlet pipeline (4-1), and the air outlet of the expansion turbine is connected with the negative pressure tank (5) through the air outlet pipeline (4-2). An air inlet valve (9) is connected in series on the air inlet pipeline (4-1), and an exhaust valve (10) is connected in series on the air outlet pipeline (4-2); a ventilation valve (16) is installed on the side wall of the cavity (1) or the side wall of the A gas pipeline (2); when the gas storage tank (3) and the negative pressure tank (5) respectively establish pressure and vacuum degree, open the air inlet valve (9) and the exhaust valve (10) to open the connection between the gas storage tank (3), the negative pressure tank (5) and the expansion turbine generator set (6). The compressed gas in the gas storage tank (3) enters the expansion turbine generator set (6) to start doing work and generating electricity. At the same time, the vacuum negative pressure established by the negative pressure tank (5) helps the expansion turbine generator set (6) improve the work power and efficiency.

2. The tidal energy power generation system according to claim 1, characterized in that The cavity (1) has an upper port (12) and a lower port (13); the upper port (12) of the cavity (1) is communicated with one end of the A gas pipeline (2); during operation, the lower port (13) of the cavity (1) is located below the water surface.

3. The tidal energy power generation system according to claim 1 or 2, characterized in that The cavity (1) is a single one or a set of two or more; when the number of cavities (1) ≥ 2, the tops of the respective cavities (1) are interconnected by pipelines, and a valve (11) is provided at the top of the upper port of each cavity (1).

4. The tidal energy power generation system according to claim 1, characterized in that The expansion turbine is a turbine expansion turbine or a piston expansion turbine; the volume of the cavity (1) is greater than the sum of the volumes of the gas storage tank (3) and the negative pressure tank (5).

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