Method and system for analyzing and designing floating type wind power foundation structure

Abstract

The invention discloses an analysis and design method and system for a floating type wind power foundation structure, and the method comprises the steps: selecting a part of section according to a preliminary design scheme of a floating type wind power foundation, and dividing the section into a plurality of floating body subareas; performing multi-body frequency domain hydrodynamic analysis on the floating body partition to obtain a multi-body hydrodynamic coefficient; calculating a rigidity coefficient at a part of the cross section; a wind turbine generator, a tower drum, a mooring system and the floating type wind power foundation are built into a multi-body coupling model, floating type wind power system time domain coupling analysis is conducted, internal force and stress of part of sections are calculated, the strength of the part of sections is checked, and the design scheme of the floating type wind power foundation is determined. According to the method, on the basis of floating body partition of the floating type foundation, the floating type foundation serves as a multi-body system composed of the multiple rigid bodies, the internal force at the connecting cross section of the multiple rigid bodies is obtained during time domain coupling analysis, analysis and design of the floating type wind power foundation structure are improved, and the design precision and the safety coefficient of the floating type wind power foundation structure are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of wind power foundation structure design, and in particular relates to an analysis and design method and system for a floating wind power foundation structure. Background Art

[0002] The offshore wind power resources are rich, equivalent to twice the offshore wind resources. The offshore wind power resources have huge development potential, and the offshore wind power development is gradually moving from the offshore to the deep sea. Floating wind power is the preferred technical means for the development of deep sea wind energy.

[0003] Floating wind turbines are simultaneously affected by upper wind loads and lower waves and currents. The dynamic response in a multi-source environment is unsteady, strongly nonlinear, and exhibits large rigid body displacement characteristics, with significant aerodynamic, elastic, and hydrodynamic coupling effects. When analyzing the motion and load of floating wind turbines, the wind turbines, towers, floating foundations, and mooring systems are currently coupled for simulation, but the floating foundations are analyzed as rigid bodies, and then the tower bottom loads, mooring cable guide hole loads, and hydrodynamic loads are applied to a separate floating foundation structure for finite element analysis, thereby verifying the structural strength of the floating foundation. However, the current methods for analyzing the motion and load of floating wind turbines are complex to operate, and the loads of key sections cannot be quickly obtained in the early stages. In addition, the influence of the deformation of the floating foundation is ignored during the coupling analysis, resulting in low accuracy in the calculated structure. Summary of the invention

[0004] The present invention provides an analysis and design method and system for a floating wind turbine foundation structure, aiming to solve the problem that the current floating wind turbine motion and load analysis method is complicated to operate, the load of key cross sections cannot be quickly obtained in the initial stage, and the influence of floating foundation deformation is ignored during coupling analysis, resulting in low calculation accuracy of the structure.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme: The present invention provides an analysis and design method for a floating wind power foundation structure, comprising the following steps: S1. Based on the basic data of the floating wind turbine, select the floating wind turbine foundation, determine the configuration and main dimensions of the floating wind turbine foundation, and form a preliminary design scheme for the floating wind turbine foundation; then select a partial cross-section of the wind turbine foundation structure and divide the floating wind turbine foundation into several floating body partitions; S2. Based on the multi-body hydrodynamic panel model of floating wind power foundation, the potential flow theory is used to perform multi-body frequency domain hydrodynamic analysis on several floating body partitions to obtain the multi-body hydrodynamic coefficients; S3. Based on the preliminary design of the floating wind power foundation, the stiffness coefficient at the partial cross section is calculated according to the position of the partial cross section; S4. The wind turbine model, tower model, mooring system model and floating wind power foundation are assembled into a multi-body coupling model. According to the preset wind-wave and current parameters, a time-domain coupling analysis of the floating wind power system is performed to calculate the internal forces of some cross sections. S5. Calculate the stress of some sections and check the strength of some sections. If the check fails, modify the preliminary design of the floating wind turbine foundation accordingly. If the check passes, determine the design of the floating wind turbine foundation based on the stress of some sections and the internal force of some sections.

[0006] In some embodiments, in S2, a hydrodynamic panel model of each floating body partition is established according to a plurality of floating body partitions, and then a multi-body hydrodynamic panel model of a floating wind power foundation is established by assuming rigid connections between adjacent floating body partitions.

[0007] In some embodiments, in S2, the velocity potential of the field of the floating wind turbine foundation is calculated using the potential flow theory, and the multi-body frequency domain hydrodynamic analysis of the floating wind turbine foundation is performed based on the velocity potential. The hydrodynamic coefficient of the floating body is calculated using the integral method, and the velocity potential satisfies formula (1): , , (1); in, is the velocity potential, is the coordinate of any point in three-dimensional space, is the incident wave frequency, is the velocity potential complex number, , and are the incident potential, scattered potential and radiation potential respectively.

[0008] Furthermore, in S2, the hydrodynamic coefficients of the multibody include the additional mass coefficient , additional damping coefficient , hydrostatic restoring coefficient , Excitation force coefficient , calculate the excitation force coefficient of the floating body under the action of waves according to the following formula (2): (2); in, is the excitation force coefficient, is the wet surface area of ​​the float, is the density of the fluid, is the unit normal vector at a point on the wet surface of the floating body, is the area element on the wet surface of the floating body.

[0009] In some embodiments, in S3, the stiffness coefficient at the partial cross section is calculated using a finite element model.

[0010] Furthermore, in S3, the stiffness coefficient at some sections is calculated as follows: When a unit force is applied to a certain degree of freedom, the displacement of the cross section in this degree of freedom is calculated using the finite element method. Then, the stiffness coefficient of this degree of freedom is obtained according to the following formula (3): (3); in, is the stiffness coefficient of the degree of freedom, To apply a unit force on a degree of freedom, is the displacement of the cross section in this degree of freedom.

[0011] Furthermore, in S3, the stiffness coefficients of the partial cross section in six degrees of freedom are calculated according to the following formula (4): (4); in, is the elastic modulus of the cross-section material, is the shear modulus of the cross-section material, is the cross-sectional area, For cross section Moment of inertia of the axis, For cross section Moment of inertia of the axis, is the polar moment of inertia of the section.

[0012] In some implementations, in S4, the time domain coupling analysis of the floating wind power system is specifically as follows: (5); in: is the wave force, calculated using the potential flow theory as follows: ; is the flow load; the calculation is as follows: ; is the wind load, including tower wind load and wind rotor wind load; The tower wind load is calculated as follows: ; The wind load on the wind rotor is calculated using the momentum blade element theory; The wind wheel thrust is ; The wind wheel torque is ; is the mooring load and is calculated using the concentrated mass method.

[0013] In some embodiments, in S5, the cross-sectional stress is checked using the following formula (6): (6); in, is the maximum stress allowed by the material; The structural stress of the floating wind turbine foundation satisfies the following formula (7): (7); in, is the stress in the partial cross section, is the cross-sectional area, is the internal force of a certain section.

[0014] The present invention also provides an analysis and design system for a floating wind power foundation structure, the system comprising a preliminary design module, a stiffness coefficient calculation module, an internal force calculation module and a verification module, wherein: The preliminary design module is used to select the floating wind power foundation based on the basic data of the floating wind turbine, determine the configuration and main dimensions of the floating wind power foundation, and form a preliminary design scheme for the floating wind power foundation; then select some sections of the wind power foundation structure and divide the floating wind power foundation into several floating body partitions; according to the multi-body hydrodynamic panel model of the floating wind power foundation, use the potential flow theory to perform multi-body frequency domain hydrodynamic analysis on several floating body partitions to obtain the multi-body hydrodynamic coefficients; The stiffness coefficient calculation module is used to calculate the stiffness coefficient of a partial section according to the position of the partial section based on the preliminary design of the floating wind power foundation; The internal force calculation module is used to combine the wind turbine model, tower model, mooring system model and floating wind power foundation into a multi-body coupling model, conduct time domain coupling analysis of the floating wind power system according to the preset wind wave and current parameters, and calculate the internal forces of some sections; The verification module is used to calculate the stress of partial cross-sections and verify the strength of partial cross-sections. If the verification fails, the preliminary design of the floating wind power foundation is modified accordingly; if the verification passes, the design of the floating wind power foundation is determined in combination with the stress of partial cross-sections and the internal force of partial cross-sections.

[0015] Compared with the prior art, the analysis and design method and system of a floating wind power foundation structure of the present invention has the following beneficial effects: The present invention provides an analysis and design method for a floating wind power foundation structure, comprising the following steps: S1, based on the basic data of a floating wind turbine generator set, selecting a floating wind power foundation, determining the configuration and main dimensions of the floating wind power foundation, and forming a preliminary design scheme for the floating wind power foundation; then selecting a partial cross section of the wind power foundation structure, and dividing the floating wind power foundation into a plurality of floating body partitions; S2, based on a multi-body hydrodynamic panel model of a floating wind power foundation, using potential flow theory to perform multi-body frequency domain hydrodynamic analysis on a plurality of floating body partitions, and obtaining the hydrodynamic coefficients of the multi-body; S3, based on the Preliminary design scheme, according to the position of the partial section, calculate the stiffness coefficient at the partial section; S4, the wind turbine model, tower model, mooring system model and floating wind power foundation are assembled into a multi-body coupling model, and the floating wind power system time domain coupling analysis is performed according to the preset wind wave current parameters, and the internal force of the partial section is calculated; S5, the stress of the partial section is calculated, and the strength of the partial section is checked. If the check fails, the preliminary design scheme of the floating wind power foundation is modified accordingly; if the check passes, the design scheme of the floating wind power foundation is determined by combining the stress of the partial section and the internal force of the partial section. The present invention divides the floating wind power foundation into several floating body partitions by selecting partial sections of the wind power foundation structure. The potential flow theory is used to perform multi-body frequency domain hydrodynamic analysis on the floating body partition to obtain the hydrodynamic coefficient. The stiffness coefficient at the partial section is calculated. The wind turbine, tower, mooring system and floating wind power foundation models are coupled, and the time domain coupling analysis is performed to calculate the internal force. Finally, the design scheme is determined by checking the strength of the partial section. As the capacity of the unit increases, the deformation effect of the floating foundation becomes more significant. The present invention is based on the division of multiple bodies, and by coupling the analysis of the stress of the floating wind power foundation structure, it adopts multi-body frequency domain hydrodynamic analysis, which simplifies the analysis process of complex structures, improves the accuracy of hydrodynamic analysis, and provides reliable data support for the initial design of the floating wind power foundation structure. In addition, the present invention comprehensively considers various environmental factors such as wind, waves, and currents to ensure the comprehensiveness of the design of the floating wind power foundation structure. Finally, through the calculation and analysis of the data and the preset strength verification standards, the rationality of the structural design is improved, which has better practical significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings in the specification are used to provide further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0017] Figure 1 A schematic diagram of a method for analyzing and designing a floating wind power foundation structure and a flow chart of a method in the system of the present invention; Figure 2It is a schematic diagram of multi-body division of a floating wind power foundation in an embodiment of a method and system for analyzing and designing a floating wind power foundation structure of the present invention. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0021] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0022] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0023] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" 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 a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] As the capacity of the unit increases, the deformation of the floating foundation becomes more significant. How to provide an analysis method for coupling the structural stress of the floating wind power foundation to improve the rationality and effectiveness of the floating foundation structure design.

[0025] like Figure 1 As shown, the present invention provides a method for analyzing and designing a floating wind power foundation structure, comprising the following steps: S1. Based on the basic data of the floating wind turbine, select the floating wind turbine foundation, determine the configuration and main dimensions of the floating wind turbine foundation, and form a preliminary design scheme for the floating wind turbine foundation; then select a partial cross-section of the wind turbine foundation structure and divide the floating wind turbine foundation into several floating body partitions; S2. Based on the multi-body hydrodynamic panel model of floating wind power foundation, the potential flow theory is used to perform multi-body frequency domain hydrodynamic analysis on several floating body partitions to obtain the multi-body hydrodynamic coefficients; S3. Based on the preliminary design of the floating wind power foundation, the stiffness coefficient at the partial cross section is calculated according to the position of the partial cross section; S4. The wind turbine model, tower model, mooring system model and floating wind power foundation are assembled into a multi-body coupling model. According to the preset wind-wave and current parameters, a time-domain coupling analysis of the floating wind power system is performed to calculate the internal forces of some cross sections. S5. Calculate the stress of some sections and check the strength of some sections. If the check fails, modify the preliminary design of the floating wind turbine foundation accordingly. If the check passes, determine the design of the floating wind turbine foundation based on the stress of some sections and the internal force of some sections.

[0026] The present invention divides the floating foundation structure into multiple floating body partitions, and different floating body partitions are connected by elastic bodies or elastic constraints. The influence of the floating body deformation can be considered in the coupling analysis to obtain the structural internal forces of the key sections. The finite element analysis of the foundation structure is carried out according to the internal forces of the key structural sections. The finite element analysis results will provide technical guidance for the optimal design of the floating foundation structure, thereby improving the effectiveness of the floating foundation structure design.

[0027] In some embodiments, specifically, the present invention carries out the selection and design of the floating wind power foundation according to the capacity of the floating wind turbine, the hydrological parameters of the target site and the standards related to floating wind power, determines the configuration and main dimensions of the floating wind power foundation, and obtains the preliminary design scheme of the floating wind power foundation. Then, according to the preliminary design scheme of the floating wind power foundation and mechanical knowledge, the section with large load or large stress or section prone to stress concentration of the floating foundation structure is selected. These sections are generally the connection of the floating foundation structure rods, the small support or the mid-span section of the foundation. According to the preliminary selected section position, the floating wind power foundation is divided into N floating body partitions (N≥1).

[0028] The present invention establishes a hydrodynamic panel model of each floating body partition according to the floating body partition of the floating wind power foundation, and assumes that adjacent floating body partitions are rigidly connected, thereby establishing a multi-body hydrodynamic panel model of the floating wind power foundation. The present invention simplifies the establishment process of the multi-body hydrodynamic panel model by establishing a hydrodynamic panel model of each floating body partition and assuming that adjacent floating body partitions are rigidly connected, thereby ensuring the accuracy of the model at the connection.

[0029] The present invention uses the potential flow theory to calculate the velocity potential of the field based on the multi-body hydrodynamic panel model of the floating wind power foundation. , the velocity potential satisfies formula (1), and the multi-body frequency domain hydrodynamic analysis of the floating wind power foundation is carried out. The hydrodynamic coefficient of the floating body is calculated using the integral method, thereby obtaining the additional mass coefficient of the floating body , additional damping coefficient , hydrostatic restoring coefficient , Excitation force coefficient , , and is a 6N×6N matrix, It is a 6N matrix. The calculation formula can refer to formula (2), and the calculation of other coefficients is similar.

[0030] The present invention adopts potential flow theory to calculate the velocity potential of the field of the floating wind power foundation, performs multi-body frequency domain hydrodynamic analysis of the floating wind power foundation based on the velocity potential, and calculates the hydrodynamic coefficient of the multi-body using the integral method. The velocity potential satisfies formula (1): , , (1); in, is the velocity potential, is the coordinate of any point in three-dimensional space, is the incident wave frequency, is the velocity potential complex number, , and are the incident potential, scattered potential and radiation potential respectively.

[0031] Based on the above, the present invention provides an accurate velocity potential calculation method, provides a basis for the calculation of the hydrodynamic coefficient, and thus improves the accuracy of the hydrodynamic analysis.

[0032] Among them, the hydrodynamic coefficients of the multibody include the additional mass coefficient , additional damping coefficient , hydrostatic restoring coefficient , Excitation force coefficient , calculate the excitation force coefficient of the floating body under the action of waves according to the following formula (2): (2); in, is the excitation force coefficient, is the wet surface area of ​​the float, is the density of the fluid, is the unit normal vector at a point on the wet surface of the floating body, is the area element on the wet surface of the floating body.

[0033] The invention provides a calculation method for the excitation force coefficient, thereby improving the accuracy of dynamic response analysis of a floating wind power foundation under wave action.

[0034] Optionally, the present invention can establish a structural finite element model of the floating wind power foundation according to the preliminary design of the floating wind power foundation, and obtain the stiffness coefficient at the cross section according to the position of the key cross section of the structure using the finite element model. Apply a unit force to a certain degree of freedom, and use the finite element method to calculate the displacement of the cross section in the degree of freedom; the stiffness coefficient of the degree of freedom.

[0035] Specifically, a unit force is applied to a certain degree of freedom, and the displacement of the cross section in this degree of freedom is calculated using the finite element method. Then, the stiffness coefficient of this degree of freedom is obtained according to the following formula (3): (3); in, is the stiffness coefficient of the degree of freedom, To apply a unit force on a degree of freedom, is the displacement of the cross section in this degree of freedom.

[0036] Alternatively, the present invention may also calculate the stiffness coefficient of a partial cross section in six degrees of freedom according to the following formula (4): (4); in, is the elastic modulus of the cross-section material, is the shear modulus of the cross-section material, is the cross-sectional area, For cross section Moment of inertia of the axis, For cross section Moment of inertia of the axis, is the polar moment of inertia of the section.

[0037] The present invention provides a specific stiffness coefficient calculation method, simplifies the stiffness coefficient calculation process, and improves the efficiency and accuracy of the calculation. At the same time, the present invention provides a comprehensive stiffness coefficient calculation method, taking into account the influence of six degrees of freedom, and improving the strength and stability of the structure.

[0038] The present invention establishes a wind turbine model, a tower model and a mooring system model in the floating wind power time domain analysis software, couples the wind turbine model, the tower model, the floating wind power foundation multi-body model and the mooring system model together, and after the wind wave and current parameters are given, the floating wind power system time domain coupling analysis can be carried out using formula (5), and then the internal force of the typical cross section can be calculated. .

[0039] (5); in: is the wave force, calculated using the potential flow theory as follows: ; is the flow load; the calculation is as follows: ; is the wind load, including tower wind load and wind rotor wind load; The tower wind load is calculated as follows: ; The wind load on the wind rotor is calculated using the momentum blade element theory; The wind wheel thrust is ; The wind wheel torque is ; is the mooring load and is calculated using the concentrated mass method.

[0040] The present invention conducts time-domain coupling analysis of floating wind power systems, taking into account wave forces, flow loads, wind loads and mooring loads, and provides a comprehensive time-domain coupling analysis method. In addition, the present invention takes into account the influence of various environmental factors, thereby improving the accuracy of the analysis.

[0041] From the above, the internal forces of the key sections of the floating wind power foundation structure under typical working conditions can be obtained: , so that the strength check of the foundation structure can be carried out. In the strength check stage, the present invention can use the finite element analysis method to calculate the cross-sectional stress , satisfying formula (6). If the strength check fails, the preliminary design scheme of the floating wind turbine foundation is modified and the coupling analysis is re-conducted. If the strength check passes, as shown in formula (7), the design scheme of the floating wind turbine foundation is preliminarily determined.

[0042] (6); in, is the maximum stress allowed by the material; The structural stress of the floating wind turbine foundation satisfies the following formula (7): (7); in, is the stress in the partial cross section, is the cross-sectional area, is the internal force of a certain section.

[0043] The present invention verifies the cross-sectional stress through the design formula criterion, determines the design scheme, and ensures the safety of the structure.

[0044] like Figure 2 As shown, in some embodiments, the present invention provides a floating body partition based on a four-column floating wind power foundation. According to the type of floating wind power foundation, it can be preliminarily determined that the place where the column and the buoy are connected is the key section, so a key section is set on the buoy near the column connection, and the floating wind power foundation is divided into seven partitions. When performing time domain coupling analysis, adjacent floating body partitions are connected using equivalent springs. Figure 2 The floating foundation structure includes the wind turbine, tower, column, mooring cable and buoy. Figure 2 The floating foundation structure is divided into seven floating foundation floating body partitions in a manner. This facilitates subsequent design and analysis. Since the current floating wind power coupling analysis method treats the floating foundation as a rigid body when performing time domain analysis, it is impossible to obtain the internal forces of key sections. Based on the floating foundation floating body partitions, the present invention treats the floating foundation as a multi-body system composed of multiple rigid bodies. When performing time domain coupling analysis, the internal forces at the connecting sections of multiple rigid bodies can be obtained, thereby improving the analysis and design of the floating wind power foundation structure, improving the design accuracy, and effectively ensuring the safety factor of the subsequent floating wind power foundation structure.

[0045] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in the industry can smoothly implement the present invention as shown in the specification and described above. However, any equivalent changes, modifications and evolutions made by technicians familiar with the profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A method for analyzing and designing a floating wind power foundation structure, characterized in that: The method comprises the following steps: S1. Based on the basic data of the floating wind turbine, select the floating wind turbine foundation, determine the configuration and main dimensions of the floating wind turbine foundation, and form a preliminary design scheme for the floating wind turbine foundation; then select a partial cross-section of the wind turbine foundation structure and divide the floating wind turbine foundation into several floating body partitions; S2. Based on the multi-body hydrodynamic panel model of floating wind power foundation, the potential flow theory is used to perform multi-body frequency domain hydrodynamic analysis on several floating body partitions to obtain the multi-body hydrodynamic coefficients; S3. Based on the preliminary design of the floating wind power foundation, the stiffness coefficient at the partial section is calculated according to the position of the partial section; S4. The wind turbine model, tower model, mooring system model and floating wind power foundation are assembled into a multi-body coupling model. According to the preset wind-wave and current parameters, a time-domain coupling analysis of the floating wind power system is performed to calculate the internal forces of some cross sections. S5. Calculate the stress of some sections and check the strength of some sections. If the check fails, modify the preliminary design of the floating wind power foundation accordingly; If the verification is passed, the design scheme of the floating wind power foundation is determined by combining the stress of some sections and the internal forces of some sections.

2. The analysis and design method of the floating wind power foundation structure according to claim 1, characterized in that: In S2, a hydrodynamic panel model of each floating body partition is established according to a plurality of floating body partitions, and then a multi-body hydrodynamic panel model of a floating wind power foundation is established by assuming that adjacent floating body partitions are rigidly connected.

3. The analysis and design method of a floating wind power foundation structure according to claim 1, characterized in that: In S2, the velocity potential of the field of the floating wind turbine foundation is calculated using the potential flow theory, and the multi-body frequency domain hydrodynamic analysis of the floating wind turbine foundation is performed based on the velocity potential. The hydrodynamic coefficient of the multi-body is calculated using the integral method, and the velocity potential satisfies formula (1): ， ， （1）； in, is the velocity potential, is the coordinate of any point in three-dimensional space, is the incident wave frequency, is the velocity potential complex number, , and are the incident potential, scattered potential and radiation potential respectively.

4. The analysis and design method of the floating wind power foundation structure according to claim 3, characterized in that: In S2, the hydrodynamic coefficients of the multibody include the additional mass coefficient , additional damping coefficient , hydrostatic restoring coefficient , Excitation force coefficient , calculate the excitation force coefficient of the floating body under the action of waves according to the following formula (2): （2）； in, is the excitation force coefficient, is the wet surface area of ​​the float, is the density of the fluid, is the unit normal vector at a point on the wet surface of the floating body, is the area element on the wet surface of the floating body.

5. The analysis and design method of a floating wind power foundation structure according to claim 1, characterized in that: In S3, the stiffness coefficient at a part of the cross section is calculated using a finite element model.

6. The analysis and design method of a floating wind power foundation structure according to claim 5, characterized in that: In S3, the stiffness coefficient at some sections is calculated as follows: When a unit force is applied to a certain degree of freedom, the displacement of the section in this degree of freedom is calculated using the finite element method. The stiffness coefficient of this degree of freedom is obtained according to the following formula (3): （3）； in, is the stiffness coefficient of the degree of freedom, To apply a unit force on a degree of freedom, is the displacement of the cross section in this degree of freedom.

7. The analysis and design method of a floating wind power foundation structure according to claim 5, characterized in that: In S3, the stiffness coefficient of the partial section in six degrees of freedom is calculated according to the following formula (4): （4）； in, is the elastic modulus of the cross-section material, is the shear modulus of the cross-section material, is the cross-sectional area, For cross section Moment of inertia of the axis, For cross section Moment of inertia of the axis, is the polar moment of inertia of the section.

8. The analysis and design method of a floating wind power foundation structure according to claim 1, characterized in that: In S4, the time domain coupling analysis of the floating wind power system is as follows: （5）； in: is the wave force, calculated using the potential flow theory as follows: ； is the flow load; the calculation is as follows: ； is the wind load, including tower wind load and wind rotor wind load; The tower wind load is calculated as follows: ； The wind load on the wind rotor is calculated using the momentum blade element theory; The wind wheel thrust is ; The wind wheel torque is ; is the mooring load and is calculated using the concentrated mass method.

9. The analysis and design method of a floating wind power foundation structure according to claim 1, characterized in that: In S5, the following formula (5) is used to check the cross-sectional stress: （6）； in, is the maximum stress allowed by the material; The structural stress of the floating wind turbine foundation satisfies the following formula (7): （7）； in, is the stress in the partial cross section, is the cross-sectional area, is the internal force of a certain section.

10. A system based on the analysis and design method of a floating wind power foundation structure according to any one of claims 1 to 9, characterized in that: The system includes a preliminary design module, a stiffness coefficient calculation module, an internal force calculation module and a verification module, wherein: The preliminary design module is used to select the floating wind power foundation based on the basic data of the floating wind turbine, determine the configuration and main dimensions of the floating wind power foundation, and form a preliminary design scheme for the floating wind power foundation; then select some sections of the wind power foundation structure and divide the floating wind power foundation into several floating body partitions; according to the multi-body hydrodynamic panel model of the floating wind power foundation, use the potential flow theory to perform multi-body frequency domain hydrodynamic analysis on several floating body partitions to obtain the multi-body hydrodynamic coefficients; The stiffness coefficient calculation module is used to calculate the stiffness coefficient of a partial section according to the position of the partial section based on the preliminary design of the floating wind power foundation; The internal force calculation module is used to combine the wind turbine model, tower model, mooring system model and floating wind power foundation into a multi-body coupling model, conduct time domain coupling analysis of the floating wind power system according to the preset wind wave and current parameters, and calculate the internal forces of some sections; The verification module is used to calculate the stress of partial cross-sections and verify the strength of partial cross-sections. If the verification fails, the preliminary design of the floating wind power foundation is modified accordingly; if the verification passes, the design of the floating wind power foundation is determined in combination with the stress of partial cross-sections and the internal force of partial cross-sections.

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