A floating offshore leeward wind turbine group

Abstract

The present invention discloses a floating offshore leeward wind turbine group, which includes a rotating platform, a generator group, and a fixing structure. The rotating platform is in a rotating column shape and has a sealed cavity inside. A stabilizing base is rotatably sleeved and installed on a part of the outer wall of the rotating platform, and the stabilizing base is connected to the seabed through the fixing structure. The generator group is composed of several leeward wind turbines installed on the rotating platform. The rotating platform is actuated by the wind received by the generator group, causing the first main axis direction of the tower of the leeward wind turbine to be parallel to the wind direction. In the present invention, the rotating platform is designed as a floating structure with a sealed cavity inside. On the basis of ensuring the support performance, the rotating platform has floating properties, reducing the total weight and cost of the machine group. The rotating platform is restricted to the designed position through the stabilizing base, which can not only meet the basic rotation requirements of the rotating platform but also play a certain role in balancing and stabilizing the support platform, enhancing the support stability of the wind turbine.

Description

Technical Field

[0001] The present invention belongs to the field of wind turbines, and more specifically, relates to a floating offshore leeward wind turbine group. Background Art

[0002] Wind power generation is the fastest-growing green energy technology in the world. While the construction of onshore wind farms is developing rapidly, people have noticed some limitations in the utilization of onshore wind energy, such as large land occupation area, noise pollution, etc. As the vast sea surface far from residential areas, not only has rich wind energy resources, but also is relatively close to the power load center (coastal economically developed areas). Therefore, offshore wind power generation naturally becomes the main direction of current new energy development.

[0003] In view of this, the present invention is specifically proposed. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a floating offshore leeward wind turbine group. To solve the above technical problems, the basic concept of the technical solution adopted by the present invention is as follows:

[0005] A floating offshore leeward wind turbine group includes:

[0006] A slewing platform, which is rotationally cylindrical, has a sealed cavity inside, and a mounting stable base is rotatably sleeved on a part of the outer wall of the slewing platform. The slewing platform floats on the sea surface, and the stable base is located above the sea surface. The inside of the stable base is annular, and a rim extending horizontally inward is provided at the top;

[0007] A fixing structure for connecting the stable base to the seabed;

[0008] A generator group composed of a number of leeward wind turbines arranged and installed on the slewing platform in an appropriate manner;

[0009] The slewing platform is actuated by the wind received by the generator group, causing the first main axis direction of the tower of the leeward wind turbine to be parallel to the wind direction.

[0010] Further, the fixing structure is a rigid foundation pile with adjustable length, at least two of which are evenly distributed circumferentially along the bottom of the stable base. The top of the foundation pile is connected to the bottom surface of the stable base, and the bottom end is connected to the seabed.

[0011] Further, the fixing structure is a cable or wire rope, at least two of which are evenly distributed circumferentially along the bottom of the stable base. One end of the cable or wire rope is connected to the bottom surface of the stable base, and the other end is connected to the seabed.

[0012] Further, a plurality of sliding guide pieces are provided on the inner wall of the stable base, and the plurality of sliding guide pieces are evenly distributed along the circumferential direction of the ring.

[0013] Further, the rotary platform is rotationally and sealingly connected to the stable base.

[0014] Further, the plurality of downwind wind turbines are arranged in rows, and the direction of the horizontal row connection in the same row is perpendicular to the first main axis direction of the downwind wind turbine tower or the positive and negative deviation is not more than 30°.

[0015] Further, the plurality of downwind wind turbines are arranged in columns, and the column direction is parallel to the first main axis direction of the downwind wind turbine tower, or the positive and negative deviation is not more than 30°.

[0016] Further, it further includes a connecting piece for connecting the downwind wind turbines to each other in pairs. There are a plurality of connecting components, which can be used to connect any two adjacent generator sets under the condition of not interfering with the rotation of the blades. The connecting component is a beam or a steel wire rope.

[0017] Further, it further includes a pre-tensioning member. The pre-tensioning member is located on the upwind side of the tower of the downwind wind turbine, one end is connected to the tower of the downwind wind turbine, and the other end is connected to the rotary platform; the pre-tensioning member includes not less than one steel wire stay rope, and the upper end of each steel wire stay rope is connected to the tower after being pre-tightened, and the lower ends are arranged at intervals on the rotary platform.

[0018] Further, the stable base is fixed on the sea surface as a floating object, and a circular sliding base for installing the rotary platform is provided on its inner wall.

[0019] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art.

[0020] 1. The present invention designs the rotary platform into a floating structure with a closed cavity inside. On the basis of ensuring the support performance, the rotary platform has the floating property, reduces the total weight and cost of the machine group, and restricts the rotary platform to the designed position through the stable base, which can not only meet the basic rotation requirement of the rotary platform, but also has a certain balance and stability ability for the support platform, enhancing the support stability of the fan.

[0021] 2. The generator group of the present invention can be arranged in rows and columns, and is reinforced through the connecting component and the pre-tensioning member. The fans of the generator group are arranged in the same direction. When the wind direction changes, the generator group drives the rotary platform to turn due to the wind force, and always keeps the first main axis direction parallel to the wind direction. It can achieve yaw alignment without setting a yaw alignment system, reducing the equipment structure design, lowering the cost and weight, and being beneficial to the construction on the sea surface.

[0022] The following further describes in detail the specific implementation manners of the present invention with reference to the accompanying drawings. Brief Description of the Drawings

[0023] The drawings, as part of this application, are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention, but do not unduly limit the present invention. Obviously, the drawings in the following description are only some embodiments, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts. In the drawings:

[0024] Figure 1 is a schematic structural view of the present invention;

[0025] Figure 2 is a schematic view of the rigid connection of the slewing platform of the present invention;

[0026] Figure 3 is a schematic view of the flexible connection of the slewing platform of the present invention;

[0027] Figure 4 is a schematic structural view of the stable base of the present invention;

[0028] Figure 5 is a schematic view of the arrangement of the pre-tensioning members of the present invention;

[0029] Figure 6 is a schematic view of the combined arrangement of the connection components and the pre-tensioning members of the present invention;

[0030] Figure 7 is a schematic structural view of the downwind wind turbine of the present invention;

[0031] Figure 8 is a schematic cross-sectional view of the tower of the present invention;

[0032] Figure 9 is a schematic view of the overall structure in the second embodiment of the present invention.

[0033] In the figures: 1, slewing platform; 2, stable base; 3, tower; 4, hub; 5, nacelle; 6, fairing; 7, blade; 8, fixing structure; 9, sliding guide; 10, wire rope; 11, connection component; 12, anchor cable; x, wind direction; y, first main shaft.

[0034] It should be noted that these drawings and textual descriptions are not intended to limit the scope of the concept of the present invention in any way, but to illustrate the concept of the present invention to those skilled in the art by reference to specific embodiments. Detailed Description of the Invention

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments in conjunction with the accompanying drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0036] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0037] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] As Figures 1 to 9 shown, a floating offshore leeward wind turbine group of the present invention includes a rotary platform 1, a generator group, and a connection component 11; the rotary platform 1 is in a rotating column shape and has a sealed cavity inside. A stable base 2 is rotatably sleeved and installed on a part of the outer wall of the rotary platform 1. The rotary platform 1 floats on the sea surface, and the stable base 2 is located above the sea surface. Refer to the attached Figure 1 , 2 figures. It can be seen that the rotary platform 1 can be welded from steel plates or made of other materials. The purpose is to form a sealed chamber with a certain floating ability on the sea surface and certain supportability to support and install the wind turbine. Here, the top surface of the rotary platform 1 is preferably designed to be higher than the top surface of the stable base 2 to raise the rotary platform 1 and reduce the possibility of seawater immersion. Of course, it can also be designed to be lower than or equal to the top surface height of the stable base 2, and the rotary platform 1 and the stable base 2 are made of materials resistant to immersion. Preferably, the rotary platform 1 is rotatably and sealingly connected to the stable base 2. The rotatable and sealing connection can ensure the sealing while allowing rotation, preventing seawater from entering the internal mechanism and causing erosion or affecting normal operation.

[0039] The stable base 2 is in a circular ring shape and has a rim extending horizontally inward at the top. Refer to the attached Figures 2 - 4It is shown that the outer edge of the stable base 2 protrudes from the slewing platform 1. The stable base 2 is located on or at least partially on the sea level, which can play a balancing and stabilizing role to prevent the slewing platform from tipping over. The stable base 2 is connected to the seabed through the fixing structure 8. The fixing structure 8 can be used to selectively fix the stable base 2 at the required position. Under the tension of the fixing structure 8, when an external force forces the slewing platform 1 to rotate, the fixing structure 8 can pull the stable base 2 to limit the movement of the slewing platform 1, so that the slewing platform 1 can achieve relative rotation with the stable base 2. Preferably, the rotational connection between the stable base 2 and the slewing platform 1 is a limited rotational connection, that is, it is difficult for the stable base 2 to separate from the slewing platform 1, which can ensure the horizontal and vertical movement of the stable base 2 relative to the slewing platform 1, thus ensuring the relative rotation of the slewing platform 1 without tipping over. Further preferably, the stable base 2 can also be designed as a sealed cavity structure, or a floating base can be selected to enhance its buoyancy effect in seawater and improve the floating support performance of the overall structure.

[0040] The generator group here consists of several downwind wind turbines installed on the slewing platform 1. The group can be appropriately arranged according to requirements. Of course, it is a prerequisite that the wind turbines do not interfere with each other during operation. They can also be arranged in rows or columns. When arranged in rows, several downwind wind turbines are arranged in a row, and the row direction is perpendicular to the first main axis direction of the downwind wind turbine tower or the positive and negative deviation is not more than 30°. When arranged in columns, several downwind wind turbines are arranged in a column, and the column direction is parallel to the first main axis direction of the downwind wind turbine tower or the positive and negative deviation is not more than 30°. The slewing platform 1 is actuated by the wind received by the generator group, causing the first main axis direction y of the tower 3 of the downwind wind turbine to be parallel to the wind direction x. It can be understood that when the generator group is blown by the wind, if there is an angle between the first main axis direction y and the wind direction x, the wind turbine blades 7 will be subjected to a large torque. At this time, the wind turbine will drive the slewing platform 1 to rotate, and the slewing platform 1 is forced to rotate. However, the stable base 2 is pulled, so the slewing platform 1 will rotate relative to the stable base 2 until the angle at which the wind turbine is subjected to the minimum torque, which is when the first main axis direction y of the wind turbine is parallel to the wind direction x and the torque is the smallest.

[0041] The fixed structure 8 can adopt rigid foundation piles with adjustable lengths, such as rods, pipes, etc. There are at least two foundation piles, which are evenly distributed circumferentially along the bottom of the stable base 2. The top end of the foundation pile is connected to the bottom surface of the stable base 2, and the bottom end is connected to the seabed. The length is adjustable to control the volume of the rotary platform 1 immersed in seawater, thereby adjusting the buoyancy of the rotary platform 1. Here, the fixed structure 8 can also adopt anchor cables 12 or cables. There are at least two anchor cables 12 or cables, which are evenly distributed circumferentially along the bottom of the stable base 2. One end of the anchor cable 12 or cable is connected to the bottom surface of the stable base 2, and the other end is connected to the seabed. The end of the anchor cable 12 or cable connected to the stable base 2 can be connected through a tensioning device. The tensioning device can adjust the tensioning, retracting and releasing of the anchor cable 12 or cable. By tightening or loosening the anchor cable 12 or cable, the height of the stable base 2 is adjusted, thereby adjusting the buoyancy of the rotary platform 1. When the position needs to be moved, the connection between the anchor cable 12 or cable and the seabed is disconnected, and the device is pulled to a suitable position by a ship to meet the selection or adjustment of the position of the generator group.

[0042] A number of sliding guide pieces 9 are provided on the inner wall of the stable base 2. The sliding guide pieces 9 are evenly distributed along the inner walls of the vertical section and the horizontal section of the stable base 2. See the appendix Figure 4 shown. The sliding guide pieces 9 are made of materials with good smoothness (small friction) and wear resistance, such as wear-resistant ceramic pieces. For the convenience of production, installation and replacement, the sliding guide pieces 9 can be made into single-piece types and then embedded and fixedly installed on the inner side of the stable base. The stable base 2 is rotationally connected to the outer wall of the rotary platform 1 through the sliding guide pieces 9. The rotary platform 1 contacts and slides relative to the sliding guide pieces 9 to achieve rotational movement. The setting of the sliding guide pieces 9 can reduce the contact surface and friction between the rotary platform 1 and the stable base 2, which is beneficial to their relative rotation. At the same time, it can avoid the problem of rapid wear caused by their direct contact. Here, the sliding guide pieces 9 adopt a detachable installation method, which is convenient for replacement.

[0043] The rotary platform 1 of the present invention can be turned passively. Under the blowing of the wind, the wind turbine will drive the rotary platform 1 to rotate to face the wind. To avoid excessive yaw rotation angle and cable entanglement, an angular displacement sensor and a yaw motor can be provided at the rotational connection between the rotary platform 1 and the stable base 2. Using the angular displacement sensor and the yaw motor to achieve steering and yaw is prior art and will not be elaborated here.

[0044] The distribution of several downwind wind turbines can be set according to requirements, such as reasonably designed according to the wind energy density at sea and the power generation capacity of downwind wind turbines to maximize power generation and minimize wake effects; fully considering power transmission and transformation schemes and installation convenience conditions; the layout spacing should not be too large to save the area of the slewing platform 1. Preferably, the generator group includes at least two rows of downwind wind turbines, and the downwind wind turbines in adjacent two rows are arranged in a staggered manner to ensure more uniform bearing capacity in all directions of the slewing platform 1, improve the overall balance of the device, and the row direction is perpendicular to the first main axis y direction of the tower 3 of the downwind wind turbine and the wind direction x. To ensure the independent operation of each wind turbine, the spacing between adjacent two rows can be set to be not less than the height of the tower 3 of the downwind wind turbine, and the spacing between adjacent downwind wind turbines in the same row can be set to be not less than 2N, where N is the rotation radius of the blade 7 of the downwind wind turbine, so as to ensure that each downwind wind turbine will not interfere with each other during operation and improve the power generation efficiency of the generator group. As a preference, when the generator group includes seven downwind wind turbines, they can be arranged in three rows in the form of 2-3-2. Among them, a total of six downwind wind turbines at both ends of each row are located at the corner points of a regular hexagon, and one is located at the centroid of the regular hexagon. See the appendix Figure 1 As shown, this distribution can ensure uniform bearing capacity at all parts of the slewing platform 1 and ensure the balance of the device.

[0045] To cope with the sway caused by sea waves and sea winds and prevent excessive head swing of each wind turbine, it further includes a connection component 11 for connecting two downwind wind turbines pairwise, that is, connecting any two in the machine group without interfering with the rotation of the blades. There are several connection components 11, and the connection component 11 can be a steel frame beam with better stability or a pre-tensioned and tightened steel wire rope with lighter weight. Preferably, when the wind turbines are arranged in rows, the connection component 11 connects the left and right adjacent downwind wind turbines in the same row. The connection component 11 is horizontally arranged and perpendicular to the wind direction x, and both ends of the connection component 11 are respectively connected to the top ends of the towers 3 of the left and right adjacent downwind wind turbines. See the appendix Figure 6 As shown, this can connect adjacent wind turbines without affecting the rotation of the blades 7 and enhance the stability of the generator group.

[0046] The lower end of the tower 3 of the downwind wind turbine is connected to the slewing platform 1, and the upper end of the tower 3 is provided with a nacelle 5. A plurality of blades 7 are rotatably connected to the nacelle 5 through a hub 4, and the plurality of blades 7 are located on the downwind side of the tower 3. Preferably, the plurality of blades 7 rotate around the main shaft, and the main shaft is parallel to the wind direction x. Since the blades 7 are located on the downwind side of the tower 3, the method of tilting the main shaft upward by 3-5° to increase the distance between the end of the blade 7 and the tower 3 is avoided. On the premise of ensuring safety, the swept area of the plurality of blades 7 is guaranteed, and wind energy loss is avoided. The hub 4 and the blades 7 on the nacelle 5 are connected to the slewing platform 1 through the tower 3. The slewing platform 1 is rotatably connected to the stable base 2. When the air flow direction, i.e., the wind direction x, changes, the blades 7 will swing with the air flow, causing the air flow to drive the tower 3 and the slewing platform 1 to rotate on the stable base 2 through the blades 7, and always keeping the main shaft direction of the downwind wind turbine parallel to the wind direction x. Thus, there is no need to install a yaw alignment device and system, which reduces costs, decreases the weight of the nacelle, improves the dynamic stiffness, and makes the structure of the tower 3 more stable.

[0047] To further improve the stability of the present invention, a pre-tensioning member is provided. The pre-tensioning member is located on the upwind side of the tower 3 of the downwind wind turbine, with one end connected to the tower 3 of the downwind wind turbine and the other end connected to the slewing platform 1. It can be understood that by connecting the two ends of the wire rope 10 to the tower 3 and the slewing platform 1 respectively and applying a certain pre-tension to the wire rope 10, the initial stress state of the cross-section of the tower 3 can be improved, and the tension generated by the wire rope 10 can offset part of the bending moment of the wind force on the tower 3, reduce the load on the tower 3, decrease the weight of the tower 3, improve the stability of the tower 3, and thus improve the overall stiffness and strength of the wind turbine. Preferably, the wire rope 10 is arranged on the upwind side of the tower 3. By arranging the wire rope 10 on the upwind side of the tower 3, part of the bending moment of the wind force on the downwind side of the tower 3 can be offset, and the load on the tower 3 can be reduced. Here, each tower 3 can be provided with more than two wire ropes 10. After each wire rope 10 is pre-tightened, the upper end is connected to the tower 3, and the lower end is arranged at intervals on the slewing platform 1. When multiple wire ropes 10 are used, after each wire rope is pre-tightened, the upper end is connected to the tower 3, and the lower end is arranged at intervals on the slewing platform 1, forming multiple tensile forces on the upwind side of the tower 3 to enhance the stability of the tower 3.

[0048] Since air flow will form turbulence behind the tower 3, in order to prevent or reduce the formation of turbulence behind the tower 3 and improve the efficiency of the wind turbine, a flow guide 6 is provided on the downwind side of the tower 3. Preferably, the cross-sectional area of the flow guide 6 gradually decreases in the direction close to the downwind side. The flow guide 6 can not only reduce the influence of turbulence on the blades 7 on the downwind side of the tower 3, but also increase the wind force received by the blades 7, enabling the blades 7 to swing better with the air flow. Under the action of the wind force, the blades 7 drive the generator nacelle 5, the tower 3 and the slewing platform 1 to rotate in the stable base 2, realizing automatic wind yaw. Further preferably, the flow guide 6 and the tower 3 are an integral part, that is, the cross-section of the tower 3 is made into a shape with a flow guiding function. The cross-section of the tower 3 is non-circular. The cross-section of the tower 3 has the largest dimension only in the direction of the first main axis y, that is, the direction of the maximum flexural rigidity. The cross-sectional area of the tower 3 gradually decreases in the direction close to the downwind side. It can be understood that the end face of the tower 3 with the maximum flexural rigidity located on the upwind side is parallel to the direction of the maximum bending moment received by the blades 7, which can reduce the dimensions of the cross-section of the tower 3 in other directions, thereby reducing the use of materials and the weight of the tower 3. Embodiment 1

[0049] As Figures 1 - 8 shown, a floating offshore leeward wind turbine group described in this embodiment includes a slewing platform 1, a stable base 2, a fixing structure 8, a generator group, a connecting component 11, and a pre-tensioning member. The slewing platform 1 is arranged on the sea surface. The slewing platform 1 is in the shape of a "convex" cylinder and has a sealed cavity inside. The top surface of the slewing platform 1 is higher than the sea surface. The stable base 2 is in a circular ring shape. The top end of the stable base 2 is provided with an inward-extending edge. Refer to the attached Figures 2 - 4 figure, the stable base 2 is rotatably sleeved and installed on the outer wall of the slewing platform 1 and is located above the sea surface. A plurality of sliding guide plates 9 are evenly arranged on the inner walls of the vertical section and the horizontal section of the stable base 2. The stable base 2 is rotationally connected to the slewing platform 1 through the sliding guide plates 9. The sliding guide plates 9 are made of wear-resistant ceramic sheets. The top surface of the slewing platform 1 is slightly higher than the top surface of the stable base 2.

[0050] The fixing structure 8 is two foundation piles with adjustable lengths. The foundation piles are vertically arranged and evenly distributed along the stable base 2. The top ends of the foundation piles are connected to the bottom surface of the stable base 2, and the bottom ends are connected to the seabed. The generator group is composed of 7 leeward wind turbines installed on the slewing platform 1. The 7 leeward wind turbines are arranged in three rows with the numbers of 2, 3, and 2, and the row direction is perpendicular to the main axis direction of the leeward wind turbines and the wind direction x. Among them, a total of six leeward wind turbines at both ends of each row are located at the corner points of a regular hexagon, and one is located at the centroid of the regular hexagon. Refer to the attached Figure 1 , 5 , 6 shown.

[0051] The lower end of the tower 3 of the downwind wind turbine is connected to the slewing platform 1. The upper end of the tower 3 is provided with a nacelle 5. A plurality of blades 7 are rotatably connected to the nacelle 5 through a hub 4. The plurality of blades 7 are located on the downwind side of the tower 3. The cross-section of the tower 3 is in a shape with a flow guiding function. The cross-section of the tower 3 is non-circular. The cross-section of the tower 3 has the largest dimension only in the first main axis y direction, that is, the direction of the maximum flexural rigidity. The cross-sectional area of the tower 3 gradually decreases in the direction close to the downwind side. See the appendix Figure 8 shown. The connecting component 11 is horizontally arranged and perpendicular to the wind direction x. The connecting component 11 is an I-shaped steel girder. There are a plurality of connecting components 11. The two ends of the connecting component 11 are respectively connected to the top ends of the towers 3 of the adjacent left and right downwind wind turbines. See the appendix Figure 6 shown. Each downwind wind turbine is provided with two wire ropes 10. After the two wire ropes 10 are pre-tensioned, the upper ends are both connected to the tower 3, and the lower ends are arranged at intervals on the slewing platform 1. Embodiment 2

[0052] As Figure 9 shown, the difference between this embodiment and the above-mentioned Embodiment 1 is that the stable base 2 is replaced by a floating base. The floating base is welded by steel plates and internally reinforced by a frame structure. The floating base is internally provided with a sealed cavity. The floating base is rotatably sleeved and installed on the outer wall of the slewing platform 1. At this time, the floating base has a floating function. The slewing platform 1 can be selected as a platform without a floating function, and the support of the overall structure is provided by the floating base.

[0053] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art of this patent, without departing from the scope of the technical solution of the present invention, can make some changes or modifications to the above-mentioned technical content as equivalent embodiments with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A floating offshore leeward wind turbine group, characterized in that, it includes: A slewing platform (1), the slewing platform (1) is rotationally cylindrical, with a sealed cavity inside. An installation stable base (2) is rotatably sleeved on a part of the outer wall of the slewing platform (1). The slewing platform (1) floats on the sea level, and the stable base (2) is located above the sea level. The stable base (2) is a floating base, welded by steel plates and reinforced with a frame structure inside. The floating base has a sealed cavity inside. The inside of the stable base (2) is annular, and there is a horizontally inward extending edge at the top. A plurality of sliding guide pieces (9) are evenly arranged on the inner walls of the vertical section and the horizontal section of the edge opening. The plurality of sliding guide pieces are evenly distributed along the circumference of the ring. The stable base (2) is rotationally connected to the slewing platform (1) through the sliding guide pieces (9), and the sliding guide pieces (9) are made of wear-resistant ceramic sheets; A fixing structure (8) for connecting the stable base (2) to the seabed; A wind turbine group composed of a number of leeward wind turbines installed on the slewing platform (1) in an appropriate manner; The slewing platform (1) is actuated by the wind received by the wind turbine group, causing the first main axis (y) direction of the tower (3) of the leeward wind turbine to be parallel to the wind direction (x).

2. A floating offshore leeward wind turbine group according to claim 1, characterized in that: The fixing structure (8) is a rigid foundation pile with adjustable length, at least two are provided, and they are evenly distributed along the circumference of the bottom of the stable base (2). The top of the foundation pile is connected to the bottom surface of the stable base (2), and the bottom end is connected to the seabed.

3. A floating offshore leeward wind turbine group according to claim 1, characterized in that: The fixing structure (8) is a cable or a wire rope, at least two are provided, and they are evenly distributed along the circumference of the bottom of the stable base (2). One end of the cable or wire rope is connected to the bottom surface of the stable base (2), and the other end is connected to the seabed.

4. A floating offshore leeward wind turbine group according to claim 1, characterized in that: The slewing platform (1) is rotationally and hermetically connected to the stable base (2).

5. A floating offshore leeward wind turbine group according to claim 1, characterized in that: The plurality of leeward wind turbines are arranged in rows, and the direction of the horizontal row connection line in the same row is perpendicular to the first main axis direction of the tower of the leeward wind turbine, or the positive and negative deviation is not more than 30°.

6. A floating offshore leeward wind turbine group according to claim 1, characterized in that: The plurality of leeward wind turbines are arranged in columns, and the column direction is parallel to the first main axis direction of the tower of the leeward wind turbine, or the positive and negative deviation is not more than 30°.

7. A floating offshore leeward wind turbine group according to claim 1, characterized in that: It further includes a connection component (11) for connecting two leeward wind turbines to each other. A number of connection components (11) are provided. Under the condition of not interfering with the rotation of the blades, it can be used to connect any two adjacent generator sets. The connection component (11) is a beam or a wire rope.

8. A floating offshore leeward wind turbine group according to claim 1, characterized in that: it further includes a pre-tensioning member. The pre-tensioning member is located on the upwind side of the tower (3) of the leeward wind turbine, one end is connected to the tower (3) of the leeward wind turbine, and the other end is connected to the slewing platform (1); the pre-tensioning member includes not less than one steel wire rope (10), and after each steel wire rope is pre-tensioned, the upper end is connected to the tower (3), and the lower ends are arranged at intervals on the slewing platform (1).

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