A floating offshore wind power generation mechanism composed of multiple buoys and a leveling method thereof

Abstract

The present invention discloses a floating offshore wind power generation mechanism composed of multiple pontoons and a leveling method thereof. The mechanism comprises pontoons, a box beam, a wind turbine generator set, a tower, and an anchoring device. The pontoons are arranged in a polygonal, vertically symmetrical manner, and the bottom of the pontoons is fixed to the seabed by an anchoring device. A box beam is horizontally provided at the lower end of the pontoons, and the pontoons are fixedly connected to form a floating platform by the box beam. Watertight platforms are horizontally provided in intervals from top to bottom inside the pontoons, and the interior of each pontoon is divided into a cavity, an active ballast tank, and a fixed ballast tank by the watertight platforms. A ballast water system is provided within the box beam, and the draft, longitudinal and transverse stability, and safe metacentric height of the floating platform are adjusted by the ballast water system. A tower is vertically fixed to one of the pontoons, and a wind turbine generator set is fixed to the upper end of the tower. The present invention has low construction difficulty and low manufacturing cost, and is suitable for use in waters deeper than 50 meters.

Description

Technical Field

[0001] The present invention relates to the technical field of offshore wind power generation, and in particular to a floating offshore wind power generation mechanism composed of multiple buoys and a leveling method thereof. Background Art

[0002] To address global warming, countries around the world are reducing carbon dioxide emissions. However, the current energy mix remains dominated by fossil fuels. To achieve carbon emission reduction goals, the proportion of clean energy must be increased. Consequently, amidst the increasingly challenging oil resource situation, countries are turning their attention to the vast resources of the ocean. Offshore wind farms, with their superior wind resources and significant advantages such as not occupying land, are gaining increasing recognition for their economic and social value. This is particularly true for islands far from land, where offshore wind power is a promising energy source.

[0003] Compared with onshore wind power, the environment in which offshore and intertidal wind turbines are located is completely different from land conditions. Offshore wind power technology is far more complex than onshore wind power. In the process of designing and manufacturing offshore wind turbines, the combined effects of offshore wind resource characteristics, ocean currents, waves, tides, seabed conditions, scouring and other factors must be considered. At the same time, in order to withstand strong wind loads, marine corrosion and wave impacts at sea, the basic structure of offshore wind turbines is complex, the technology is difficult and the construction cost is high.

[0004] Currently, offshore wind turbines are mostly located in coastal areas with water depths of 10-30 meters and approximately 10-15 kilometers from the coastline, and fixed foundation structures are widely used. However, these shallow, nearshore areas are often restricted by various factors, including hard constraints such as military zones and shipping lanes, soft constraints such as fishermen's interests and planning conflicts, technical constraints such as wind resources and seabed conditions, environmental constraints such as noise, and economic constraints. From a resource perspective, the majority of global wind resources are located in waters deeper than 60 meters. These deep and deep sea areas offer large areas, good wind resources, and great potential for development. However, as water depth increases, fixed foundation structures become less suitable for offshore wind farms, and their construction costs increase dramatically. To overcome these limitations and explore and develop the richer potential of deep-sea wind energy, the development of offshore wind farms is gradually shifting from shallow waters to deep seas.

[0005] The floating structure of a floating wind turbine is a deep-water structural form of the foundation structure of an offshore wind turbine. It can overcome the disadvantage that the foundation structure installed at the bottom of the seabed is limited by water depth. It is generally used in sea areas with a water depth of more than 50m. Therefore, the design and development of an offshore wind turbine floating platform with good stability, simple structure and strong versatility is of great significance to my country's development of new energy and adjustment of energy structure. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a floating offshore wind power generation mechanism composed of multiple buoys and a leveling method thereof. The floating platform has high strength and good stability, and is capable of withstanding large winds and waves. Moreover, the number of buoys can be increased according to demand, thereby increasing the area occupied by the floating platform, ensuring that the wind turbine generator set can operate normally even in large winds and waves.

[0007] To solve the above technical problems, the present invention adopts the following technical solution: The present invention is a floating offshore wind power generation structure composed of multiple pontoons, the innovation of which lies in: comprising pontoons, box beams, wind turbine generator sets, towers and mooring devices; 3 to 6 pontoons are arranged in a polygonal vertical symmetrical pattern, and the bottom of each pontoon is fixed to the seabed by an anchoring device; box beams are horizontally provided at the lower ends of all the pontoons, and the pontoons are fixedly connected together by the box beams to form a floating platform, and the pontoons provide buoyancy to support the floating platform; Inside each pontoon, several matching watertight platforms are horizontally arranged in sequence from top to bottom, and the interior of the corresponding pontoon is divided into a cavity on the top layer, several active ballast tanks in the middle layer, and a fixed ballast tank on the bottom layer by the watertight platforms; a ballast water system is provided in the box beam, and the draft, longitudinal and lateral stability, and safe metacentric height of the floating platform are adjusted by the ballast water system; a tower is vertically fixed on one of the pontoons, and a wind turbine is fixed at the upper end of the tower, so that wind power generation is carried out by the wind turbine.

[0008] Preferably, each of the pontoons has a circular cross-section or a rectangular cross-section, and when there are four pontoons, a cross-shaped box beam is used as the box beam. The four pontoons are arranged vertically symmetrically in a quadrilateral, and the four ends of the cross-shaped box beam are fixedly connected to the corresponding pontoons, thereby assembling into a floating platform.

[0009] Preferably, horizontal frame members and a square frame structure are arranged in the box beam, and vertically distributed frame members and a horizontal annular frame are arranged in the pontoon, thereby ensuring the overall structural strength of the floating platform.

[0010] Preferably, a sway control plate is installed at the bottom of each of the buoys, each of the sway control plates is hexagonal and has sharp edges, so that the movement of the floating platform is reduced by the sway control plate; each of the sway control plates can be made of one layer of steel plate or more than two layers of steel plates, and adjacent steel plates are connected by steel round pipes and fixed by vertical welding.

[0011] Preferably, the ballast water system consists of a ballast water pump, ballast water pipelines, ballast tanks and related valve components. It can inject or discharge ballast water into or out of the ballast tanks according to changes in the external environment to ensure the normal operation of the wind turbine generator set, so as to adjust the draft, longitudinal and lateral stability, and safe metacentric height of the floating platform; at the same time, it can reduce the deformation of the floating platform, thereby avoiding excessive bending moment and shear force, and reducing the vibration of the floating platform.

[0012] Preferably, it also includes an automatic balancing device and a liquid level measuring device; ballast water is also loaded in the active ballast tank of each of the buoys, and the ballast water circulates in the active ballast tank of the corresponding buoy through the automatic balancing device, and then the floating platform is ensured to be in a positive floating state through the automatic balancing device; a liquid level measuring device is also installed in the active ballast tank of each of the buoys, and the liquid level of the ballast water in the corresponding active ballast tank is measured in real time by the liquid level measuring device; metal, concrete or ballast water is loaded in the fixed ballast tank of each of the buoys to achieve fixed ballast, thereby lowering the center of gravity of the floating platform and ensuring its stability.

[0013] Preferably, the automatic balancing device includes a water pump, a control device, a ballast water pipe and a water valve; the water pump is arranged in the box beam, and ballast water pipes are respectively connected to it around the box beam in the direction of the corresponding buoy, and a water valve is provided on each of the ballast water pipes; the other end of each of the ballast water pipes is respectively connected to the corresponding active ballast tank of the corresponding buoy; inclination sensors are respectively arranged in the x-axis and y-axis directions on the box beam, and each of the inclination sensors is electrically connected to the control device of the automatic balancing device, and monitors the inclination angle of the floating platform through the inclination sensor; the automatic balancing device adjusts the water distribution in the corresponding active ballast tank according to the inclination data transmitted by the inclination sensor, thereby ensuring that the wind turbine generator set is within the allowable inclination range of ±2°.

[0014] Preferably, a monitoring instrument and equipment room is arranged on the top deck of one of the pontoons, and a platform floating state calculation system is installed in the monitoring instrument and equipment room; the platform floating state calculation system is respectively connected to each of the liquid level measuring devices, and the ballast water then obtains the ballast water level data of the active ballast tank corresponding to each pontoon. The platform floating state calculation system calculates the gravitational moment in the x, y, and z directions generated by the wind turbine, tower, pontoon, cross-shaped box beam and ballast water, as well as the buoyancy moment generated by the pontoon and cross-shaped box beam, and then calculates the ballast water weight of the active ballast tank corresponding to each pontoon based on the aerodynamic load of the wind turbine and the moment balance of the overall structure in the x, y, and z directions.

[0015] Preferably, a wind meter is installed on the top of one of the buoys, and the wind direction and wind speed are measured by the wind meter; a wave meter and a current meter are installed on the underwater part of one of the buoys close to the water surface, and the height of the waves is measured by the wave meter, and the speed of the current is measured by the current meter; one of the buoys is also equipped with sensors for measuring strain, acceleration and displacement, so as to obtain the changes in the deformation, acceleration and displacement parameters of the floating platform in real time, and feed them back in real time to the floating platform structure motion monitoring system; a remote monitoring device is also provided on one of the buoys, and the remote monitoring device is used to remotely monitor whether the wind turbine generator set is operating normally.

[0016] The innovative point of the present invention's leveling method for a floating offshore wind turbine generator system composed of multiple buoys is that when the inclination angle measured by the inclination sensor exceeds a certain safety range and does not decrease within 1 minute, the automatic balancing device is activated to keep the floating platform in an upright state. The specific process is as follows:

[0017] (1) The platform floating state calculation system calculates the weight of the ballast water in a pair of active ballast tanks arranged diagonally along the x-axis or y-axis when the floating platform reaches the positive floating state, and then starts the water pump to adjust the ballast water volume in the ballast tanks in the buoy until the inclination angle transmitted by the inclination sensor is within the allowable range of normal power generation of the wind turbine generator set;

[0018] (2) When encountering severe weather and large waves, start the water pump to increase the ballast water volume in each ballast tank in the buoy, thereby reducing the horizontal and vertical movement of the entire structure of the floating platform and lowering the center of gravity of the entire structure of the floating platform;

[0019] (3) When the weather improves and the waves are smaller, start the water pump to reduce the ballast water in the ballast tanks in the buoy;

[0020] (4) When the floating platform is shaken beyond the preset amplitude by the influence of sea wind and waves, the automatic balancing device is activated. During the period when the floating platform tilts toward the x-axis or y-axis, the ballast water distribution in the diagonally arranged active ballast tanks is adjusted in the opposite direction of the shaking. The stabilizing torque generated by the moving ballast water in the ballast tanks and the disturbance torque of the waves offset each other, thereby reducing the shaking of the floating platform and ensuring the stable and normal operation of the wind turbine generator set.

[0021] (5) When the external wave period changes, the periodic changes of the shaking of the floating platform in the x-axis or y-axis direction are observed based on the inclination data transmitted by the tilt sensor, and then the speed of the water flow is changed by controlling the opening and closing size of the water valve, thereby avoiding unnecessary increase in shaking caused by changes in the wave period.

[0022] Beneficial effects of the present invention:

[0023] (1) The floating platform of the present invention has high strength and good stability, and is capable of withstanding large winds and waves. In addition, the number of buoys can be increased as needed, thereby increasing the area occupied by the floating platform, ensuring that the wind turbine generator set can operate normally even in large winds and waves.

[0024] (2) The present invention adopts a structural design of multiple buoys, which has a small waterplane area and is subject to small wave loads. The multiple buoys are arranged at intervals, which increases the moment of inertia of the waterplane and improves the stability of the floating platform. It has good hydrodynamic performance under the action of wind and waves and has a small motion response.

[0025] (3) The present invention significantly reduces the vertical movement of the floating platform by providing a sway control plate, thereby ensuring the normal operation of the wind turbine generator set;

[0026] (4) The present invention divides the interior of the buoy into several watertight compartments. If the buoy is hit by a ship or other structure near the waterline, even if one compartment is damaged and flooded, the floating platform can still maintain its buoyancy, thereby ensuring the safety of the floating platform and the wind turbine generator set.

[0027] (5) The present invention can monitor the inclination of the floating platform in real time by providing an inclination sensor, and then cooperate with the automatic balancing device to level the floating platform and reduce the swaying amplitude of the floating platform by moving the ballast water, thereby ensuring that the inclination angle of the floating platform is limited under the action of wind and waves, so that the floating platform is in a positive floating state, thereby ensuring the normal operation of the wind turbine generator set;

[0028] (6) The present invention has low construction difficulty and low manufacturing cost, and is suitable for deep waters of more than 50 meters. The floating platform used has a simple structure and strong practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work. Figure 1 The figure is a schematic structural diagram of a floating offshore wind power generation mechanism composed of multiple buoys according to the present invention.

[0030] Figure 2 This is a schematic structural diagram of the buoy of the present invention when the buoy has a circular cross-section.

[0031] Figure 3 This is a schematic structural diagram of the buoy of the present invention when the buoy has a rectangular cross-section.

[0032] Figure 4 Schematic diagram of the arrangement of the tilt sensor of the present invention.

[0033] Figure 5 Schematic diagram of the layout of the automatic balancing device of the present invention.

[0034] Among them, 1- buoy; 2- box beam; 3- wind turbine; 4- tower; 5- anchoring device; 6- seabed; 7- water pump; 8- ballast water pipe; 9- water valve; 10- tilt sensor; 11- sway plate. DETAILED DESCRIPTION

[0035] The technical solution of the present invention will be clearly and completely described below through specific implementation methods.

[0036] The present invention is a floating offshore wind power generation mechanism composed of multiple buoys 1, including buoys 1, box beams 2, wind turbine generator sets 3, towers 4 and mooring devices 5; the specific structure is as follows Figures 1 to 5 As shown, 3 to 6 pontoons 1 are arranged in a polygonal, vertically symmetrical manner, and the bottom of each pontoon 1 is fixed to the seabed 6 via an anchoring device 5. Box beams 2 are horizontally arranged at the lower ends of all pontoons 1, and the pontoons 1 are fixedly connected together by the box beams 2 to form a floating platform, and the buoyancy supporting the floating platform is provided by the pontoons 1. Each pontoon 1 has a circular or rectangular cross-section, and when there are four pontoons 1, the box beam 2 is a cross-shaped box beam. The four pontoons 1 are arranged in a quadrilateral, vertically symmetrical manner, and the four ends of the cross-shaped box beam are fixedly connected to the corresponding pontoons 1. The present invention arranges horizontal frame members and a square frame structure in the box beam 2, and arranges vertically distributed frame members and a horizontal ring frame in the pontoons 1, thereby improving the overall structural strength of the floating platform.

[0037] The present invention provides a plurality of matching watertight platforms in a horizontal manner from top to bottom inside each buoy 1, and the watertight platforms divide the interior of the corresponding buoy 1 into a cavity on the top layer, several active ballast tanks in the middle layer, and a fixed ballast tank on the bottom layer. Among them, two vertical bulkheads in the ballast tank of the buoy 1 divide the interior of the first ballast tank into four small watertight compartments. In addition, a watertight anchor chain compartment can also be provided in the buoy 1 for storing anchor chains. Figures 1 to 5 As shown, a ballast water system is installed within the box beam 2, and is used to adjust the floating platform's draft, longitudinal and lateral stability, and safe metacentric height. A tower 4 is vertically fixed to one of the pontoons 1, and a wind turbine 3 is fixed to the upper end of the tower 4, thereby generating wind power. Compared with conventional floating wind turbine foundations, this invention eliminates the central pontoon 1 and large pontoon tank, and arranges the upper wind turbine 3 on one of the pontoons 1, thereby reducing structural complexity.

[0038] The ballast water system consists of a ballast water pump, ballast water pipelines, ballast tanks, and related valves. The ballast water system can, in response to changes in the external environment, inject or discharge ballast water into or out of the ballast tanks to ensure the normal operation of the wind turbine generator set 3, thereby adjusting the draft, longitudinal and lateral stability, and safe metacentric height of the floating platform; at the same time, it can reduce the deformation of the floating platform, thereby avoiding excessive bending moment and shear force, and reducing the vibration of the floating platform.

[0039] The present invention also includes a hexagonal swash plate 11 mounted at the bottom of each buoy 1, thereby increasing the additional mass during the movement of the floating platform. Furthermore, the sharp edges of the swash plates 11 increase the viscous damping caused by vortex shedding, thereby allowing the natural period of the floating platform foundation to avoid the concentrated range of wave energy, thereby reducing the movement of the floating platform. Each swash plate 11 can be made of a single layer of steel plate or of two or more layers of steel plate, and adjacent steel plates are connected by steel circular pipes and fixed by vertical welding.

[0040] In the present invention, ballast water is also loaded in the active ballast tank of each buoy 1, and the ballast water circulates in the active ballast tank of the corresponding buoy 1 through the automatic balancing device, thereby ensuring that the floating platform is in a positive floating state through the automatic balancing device; Figures 1 to 5 As shown, a liquid level measuring device is also installed in the active ballast tank of each buoy 1, and the liquid level measuring device is used to measure the liquid level of the ballast water in the corresponding active ballast tank in real time; metal, concrete or ballast water is loaded in the fixed ballast tank of each buoy 1 to achieve fixed ballast, thereby lowering the center of gravity of the floating platform and improving its stability.

[0041] Among them, such as Figure 5 As shown, the automatic balancing device includes a water pump 7, a control device, a ballast water pipe 8 and a water valve 9; the water pump 7 is arranged in the box beam 2, and ballast water pipes 8 are respectively connected to it in the direction of the corresponding buoy 1, and a water valve 9 is provided on each ballast water pipe 8; the other end of each ballast water pipe 8 is respectively connected to the corresponding active ballast tank of the corresponding buoy 1; inclination sensors 10 are respectively arranged in the x-axis and y-axis directions on the box beam 2, and each inclination sensor 10 is respectively electrically connected to the control device of the automatic balancing device, and monitors the inclination angle of the floating platform through the inclination sensor 10; the automatic balancing device adjusts the water distribution in the corresponding active ballast tank according to the inclination data transmitted by the inclination sensor 10, thereby ensuring that the wind turbine generator set 3 is within the allowable inclination range of ±2°.

[0042] In the present invention, a monitoring instrument and equipment room is arranged on the top deck of one of the pontoons 1, and a platform floating state calculation system is installed in the monitoring instrument and equipment room; the platform floating state calculation system is respectively connected to each liquid level measuring device, and the ballast water then obtains the ballast water level data of the active ballast tank corresponding to each pontoon 1. The platform floating state calculation system calculates the gravitational moment in the x, y, and z directions generated by the wind turbine 3, tower 4, pontoon 1, cross-shaped box beam and ballast water, as well as the buoyancy moment generated by the pontoon 1 and the cross-shaped box beam, taking into account the aerodynamic load of the wind turbine, and then calculates the ballast water weight of the active ballast tank corresponding to each pontoon 1 based on the moment balance in the x, y, and z directions of the overall structure; wherein, the inclination sensor 10 is connected to the platform floating state calculation system and transmits the inclination angle data of the floating platform to the platform floating state calculation system.

[0043] The present invention further installs a wind meter on the top of one of the buoys 1, and then measures the wind direction and wind speed through the wind meter; a wave meter and a current meter are also installed on the underwater part of one of the buoys 1 close to the water surface, and the wave meter is used to measure the height of the waves, and the current velocity is measured by the current meter. The data acquisition system summarizes the data measured by the wind meter, the wave meter and the current meter, and feeds back the data in real time to the environmental monitoring system. The environmental monitoring system can calculate the wind, wave and current loads on the floating platform structure with the help of the measured wind speed and direction, wave height and direction and current velocity.

[0044] In the present invention, one of the buoys 1 is further equipped with a sensor for measuring strain, acceleration, and displacement, thereby obtaining real-time changes in the deformation, acceleration, and displacement parameters of the floating platform, and feeding back the information in real time to the floating platform structure motion monitoring system. If the deformation, displacement, and acceleration parameters of the structure exceed the range, the floating platform structure motion monitoring system will issue an alarm to alert the staff. At the same time, the floating platform structure motion monitoring system will feed back the monitored parameters to the shore-based office through a remote communication system, so that the shore-based personnel can make quick decisions and ensure the safety of the floating platform.

[0045] The present invention further provides a remote monitoring device on one of the buoys 1, and remotely monitors whether the wind turbine generator set 3 is operating normally through the remote monitoring device, and alarms for faults, so as to improve the safety and reliability of system operation and maintenance, making power generation operation safer and more reliable.

[0046] The present invention provides a leveling method for a floating offshore wind turbine generator system composed of multiple buoys 1. When the tilt angle measured by the tilt sensor 10 exceeds a certain safety range, in order to prevent the floating platform from being tilted too much for a long time, and the tilt angle does not decrease within 1 minute, the automatic balancing device is activated to keep the floating platform in an upright floating state. The specific process is as follows:

[0047] (1) The platform floating state calculation system calculates the weight of the ballast water in a pair of active ballast tanks arranged diagonally along the x-axis or y-axis when the floating platform reaches the positive floating state, and then starts the water pump 7 to adjust the ballast water volume in the ballast tanks in the buoy 1 until the inclination angle transmitted by the inclination sensor 10 is within the allowable range for normal power generation of the wind turbine 3;

[0048] (2) When encountering severe weather and large waves, the water pump 7 is started to increase the ballast water volume of each ballast tank in the buoy 1, thereby reducing the horizontal and vertical movement of the entire structure of the floating platform and lowering the center of gravity of the entire structure of the floating platform;

[0049] (3) When the weather improves and the waves are smaller, start the water pump 7 to reduce the ballast water in each ballast tank in the buoy 1;

[0050] (4) When the floating platform is shaken beyond the preset amplitude by the influence of sea wind and waves, the automatic balancing device is activated. During the period when the floating platform tilts toward the x-axis or y-axis, the ballast water distribution in the diagonally arranged active ballast tanks is adjusted in the direction opposite to the shaking. The stabilizing torque generated by the moving ballast water in the ballast tanks and the disturbance torque of the waves are offset, thereby reducing the shaking of the floating platform and ensuring the stable and normal operation of the wind turbine generator set 3.

[0051] (5) When the external wave period changes, the periodic changes of the shaking of the floating platform in the x-axis or y-axis direction are observed according to the inclination data transmitted by the tilt sensor, and then the speed of the water flow is changed by controlling the opening and closing size of the water valve 9, thereby avoiding unnecessary increase in shaking caused by the change in wave period.

[0052] Beneficial effects of the present invention:

[0053] (1) The floating platform of the present invention has high strength and good stability, and is capable of withstanding large winds and waves. In addition, the number of buoys 1 can be increased as needed, thereby increasing the area occupied by the floating platform, ensuring that the wind turbine generator set 3 can operate normally even in large winds and waves;

[0054] (2) The present invention adopts a structural design of multiple buoys 1, which has a small waterplane area and is subject to small wave loads. The multiple buoys 1 are arranged at intervals, which increases the moment of inertia of the waterplane and improves the stability of the floating platform. It has good hydrodynamic performance under the action of wind and waves and has a small motion response.

[0055] (3) The present invention significantly reduces the vertical movement of the floating platform by providing a sway control plate 11, thereby ensuring the normal operation of the wind turbine generator set 3;

[0056] (4) The present invention divides the interior of the buoy 1 into several watertight compartments. If the buoy is hit by a ship or other structure near the waterline, even if one compartment is damaged and flooded, the floating platform can still maintain its buoyancy, thereby ensuring the safety of the floating platform and the wind turbine 3.

[0057] (5) The present invention can monitor the inclination of the floating platform in real time by providing an inclination sensor 10, and then cooperate with the automatic balancing device to level the floating platform and reduce the swaying amplitude of the floating platform by moving the ballast water, thereby ensuring that the inclination angle of the floating platform is limited under the action of wind and waves, so that the floating platform is in a positive floating state, thereby ensuring the normal operation of the wind turbine generator set 3;

[0058] (6) The present invention has low construction difficulty and low manufacturing cost, and is suitable for deep waters of more than 50 meters. The floating platform used has a simple structure and strong practicality.

[0059] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements to the technical solutions of the present invention made by ordinary engineering technicians in this field should fall within the scope of protection of the present invention. The technical contents to be protected by the present invention have been fully recorded in the technical requirements.

Claims

1. A method for leveling a floating offshore wind turbine generator system comprising multiple buoys, characterized in that: The floating offshore wind power generation mechanism includes a buoy, a box beam, a wind turbine generator set, a tower and an anchoring device; the four buoys are arranged in a polygonal vertical symmetry, and the bottom of each buoy is fixed to the seabed by an anchoring device; a box beam is horizontally provided at the lower end of all the buoys, and the buoys are fixedly connected together by the box beam to form a floating platform, and the buoyancy of the floating platform is provided by the buoy; a plurality of matching watertight platforms are horizontally provided in sequence from top to bottom inside each buoy, and the interior of the corresponding buoy is divided into a cavity on the top layer, a plurality of active ballast tanks in the middle layer, and a fixed ballast tank on the bottom layer by the watertight platforms; a ballast water system is provided in the box beam, and the draft, longitudinal and transverse stability, and safe metacentric height of the floating platform are adjusted by the ballast water system; a tower is vertically fixed on one of the buoys, and a wind turbine generator set is fixed on the upper end of the tower, and wind power generation is performed by the wind turbine generator set; Each of the pontoons has a circular or rectangular cross-section, and when there are four pontoons, a cross-shaped box beam is used as the box beam. The four pontoons are arranged vertically symmetrically in a quadrilateral, and the four ends of the cross-shaped box beam are fixedly connected to the corresponding pontoons respectively, thereby assembling a floating platform. A swash plate is installed at the bottom of each buoy. Each swash plate is hexagonal and has sharp edges, so as to reduce the movement of the floating platform. Each swash plate is made of two or more layers of steel plates, and adjacent steel plates are connected by steel round pipes and fixed vertically by welding. The system further comprises an automatic balancing device; ballast water is loaded in the active ballast tank of each buoy, and the ballast water circulates in the active ballast tank of the corresponding buoy through the automatic balancing device, thereby ensuring that the floating platform is in an upright floating state through the automatic balancing device; Inclination sensors are arranged on the box beam in the x-axis and y-axis directions, and each of the inclination sensors is electrically connected to the control device of the automatic balancing device, and the inclination angle of the floating platform is monitored by the inclination sensors; A monitoring instrument room is arranged on the top deck of one of the buoys, and a platform floating state calculation system is installed in the monitoring instrument room; The leveling method is to start the automatic balancing device to keep the floating platform in an upright state when the inclination angle measured by the inclination sensor exceeds a certain safety range and does not decrease within 1 minute. The specific process is as follows: (1) The platform floating state calculation system calculates the weight of the ballast water in a pair of active ballast tanks arranged diagonally along the x-axis or y-axis when the floating platform reaches the positive floating state, and then starts the water pump to adjust the ballast water volume in the ballast tanks in the buoy until the inclination angle transmitted by the inclination sensor is within the allowable range of normal power generation of the wind turbine generator set; (2) When encountering severe weather and large waves, start the water pump to increase the ballast water volume in each ballast tank in the buoy, thereby reducing the horizontal and vertical movement of the entire structure of the floating platform and lowering the center of gravity of the entire structure of the floating platform; (3) When the weather improves and the waves are smaller, start the water pump to reduce the ballast water in the ballast tanks in the buoy; (4) When the floating platform is shaken beyond the preset amplitude by the influence of sea wind and waves, the automatic balancing device is activated. During the period when the floating platform tilts toward the x-axis or y-axis, the ballast water distribution in the diagonally arranged active ballast tanks is adjusted in the opposite direction of the shaking. The stabilizing torque generated by the moving ballast water in the ballast tanks and the disturbance torque of the waves offset each other, thereby reducing the shaking of the floating platform and ensuring the stable and normal operation of the wind turbine generator set. (5) When the external wave period changes, the periodic changes of the shaking of the floating platform in the x-axis or y-axis direction are observed based on the inclination data transmitted by the tilt sensor, and then the speed of the water flow is changed by controlling the opening and closing size of the water valve, thereby avoiding unnecessary increase in shaking caused by changes in the wave period.

2. The leveling method of a floating offshore wind turbine generator system composed of multiple buoys according to claim 1, characterized in that: Horizontal frame members and a square frame structure are arranged in the box beam, and vertically distributed frame members and a horizontal ring frame are arranged in the pontoon, thereby ensuring the overall structural strength of the floating platform.

3. The leveling method for a floating offshore wind turbine generator system composed of multiple buoys according to claim 1, characterized in that: The ballast water system consists of a ballast water pump, ballast water pipelines, ballast tanks, and related valve components. Based on changes in the external environment, the system can inject or discharge ballast water into or out of the ballast tanks to ensure the normal operation of the wind turbine generator set, thereby adjusting the draft, longitudinal and lateral stability, and safe metacentric height of the floating platform. At the same time, it can also reduce deformation of the floating platform, thereby avoiding excessive bending moments and shear forces and reducing vibration of the floating platform.

4. The leveling method for a floating offshore wind turbine generator system composed of multiple buoys according to claim 1, characterized in that: It also includes a liquid level measuring device; a liquid level measuring device is also installed in the active ballast tank of each of the buoys, and the liquid level of the ballast water in the corresponding active ballast tank is measured in real time by the liquid level measuring device; metal, concrete or ballast water is loaded in the fixed ballast tank of each of the buoys to achieve fixed ballast, thereby lowering the center of gravity of the floating platform and ensuring its stability.

5. The leveling method of a floating offshore wind turbine generator system composed of multiple buoys according to claim 4, characterized in that: The automatic balancing device includes a water pump, a control device, a ballast water pipe and a water valve; the water pump is arranged in the box beam, and ballast water pipes are respectively connected to it on all four sides relative to the direction of the corresponding buoy, and a water valve is provided on each of the ballast water pipes; the other end of each of the ballast water pipes is respectively connected to the corresponding active ballast tank of the corresponding buoy; the automatic balancing device adjusts the water distribution in the corresponding active ballast tank according to the inclination data transmitted by the inclination sensor, thereby ensuring that the wind turbine generator set is within the allowable inclination range of ±2°.

6. The leveling method of a floating offshore wind turbine generator system composed of multiple buoys according to claim 5, characterized in that: The platform floating state calculation system is respectively connected to each of the liquid level measuring devices to obtain the ballast water level data of the active ballast tank corresponding to each buoy. The platform floating state calculation system calculates the gravitational moment in the x, y, and z directions generated by the wind turbine, tower, buoy, cross-shaped box beam and ballast water, as well as the buoyancy moment generated by the buoy and cross-shaped box beam, and then calculates the ballast water weight of the active ballast tank corresponding to each buoy based on the aerodynamic load of the wind turbine and the moment balance of the overall structure in the x, y, and z directions.

7. The leveling method of a floating offshore wind turbine generator system composed of multiple buoys according to claim 6, characterized in that: A wind meter is also installed on the top of one of the buoys, and the wind direction and wind speed are measured by the wind meter; a wave meter and a current meter are also installed on the underwater part of one of the buoys close to the water surface, and the wave height is measured by the wave meter, and the speed of the current is measured by the current meter; one of the buoys is also equipped with sensors for measuring strain, acceleration and displacement, so as to obtain the changes in the deformation, acceleration and displacement parameters of the floating platform in real time, and feed them back in real time to the floating platform structure motion monitoring system; a remote monitoring device is also provided on one of the buoys, and the remote monitoring device is used to remotely monitor whether the wind turbine generator set is operating normally.

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