System-level coupling modeling method, system, equipment and medium for multi-wind-wheel multi-tower-drum floating type wind turbine generator

Abstract

The invention discloses a system-level coupling modeling method, system, equipment and medium for a multi-wind-wheel multi-tower-drum floating type wind turbine generator set, and relates to the field of simulation modeling, and the method comprises the steps that parameter information of the multi-wind-wheel multi-tower-drum floating type wind turbine generator set is obtained, and a multi-system structural dynamics model is obtained based on the parameter information of the multi-wind-wheel multi-tower-drum floating type wind turbine generator set; the unsteady aerodynamic model, the hydrodynamic model and the mooring structure dynamic model are used for outputting aerodynamic loads, hydrodynamic loads and mooring cable tension, the aerodynamic loads, the hydrodynamic loads and the mooring cable tension are fed back to the multi-system structure dynamic model, and based on a Lagrange framework, the models are subjected to joint simulation operation through a joint simulation interface, so that the mooring cable tension is obtained. And the multi-wind-wheel and multi-tower-drum floating type wind turbine generator is designed. According to the method, a complete system dynamics model can be established, and complete machine level rapid evaluation and engineering iteration under multiple working conditions can be supported.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of simulation modeling, in particular to a system-level coupling modeling method, system, device and medium for a multi-rotor multi-tower floating wind turbine. BACKGROUND

[0002] With the rapid development of wind energy technology, offshore wind power gradually expands to the deep sea area to obtain more abundant and stable wind resources. In this process, the traditional single machine architecture of floating wind turbines faces problems such as structural size expansion, load increase, and system stability decline, which restricts its large-scale development. To improve power density, structural flexibility and layout efficiency, multi-rotor multi-tower floating wind turbines are becoming an important development direction for the next generation of offshore wind power.

[0003] Current mainstream wind power simulation software (such as GH Bladed, OpenFAST, etc.) supports partial module customization and extension, but still has obvious limitations in multi-rotor structure, inclined tower modeling, and controller and platform degree of freedom coupling. There is a lack of a unified system-level modeling framework, making it difficult to meet the simulation needs of such new types of units in design development and control strategy optimization.

[0004] In contrast, the computational fluid dynamics (CFD) method can be used to simulate the wake structure and its influence on the aerodynamic performance of the rear rotor with high precision, but it usually does not consider system feedback such as structural elasticity, controller response and platform motion, making it difficult to establish a complete system dynamics model. At the same time, traditional CFD methods rely on full flow field solving and fine grid discretization, and need to solve large-scale coupling problems of fluid, structure and wake interaction at the same time, resulting in large overall calculation scale, high convergence requirement and long solution period. Therefore, the CFD method has the problems of high cost and low efficiency in system-level modeling and large-scale design analysis, making it difficult to meet the whole machine level rapid evaluation and engineering iteration under multiple working conditions. SUMMARY

[0005] The purpose of the present application is to provide a system-level coupling modeling method, system, device and medium for a multi-rotor multi-tower floating wind turbine, to solve the problems of difficulty in establishing a complete system dynamics model and difficulty in supporting whole machine level rapid evaluation and engineering iteration under multiple working conditions.

[0006] To achieve the above-mentioned purpose, the present application provides the following solutions:

[0007] In a first aspect, the present application provides a system-level coupling modeling method for a multi-rotor multi-tower floating wind turbine, comprising:

[0008] Obtaining parameter information of the multi-rotor multi-tower floating wind turbine; the parameter information includes environmental information and working condition configuration information; the environmental information includes wind condition data and wave data; the working condition configuration information includes wind speed, turbulence intensity, wave height, spectral peak period and operating state; the operating state includes power generation state, idling state and shutdown state;

[0009] Based on the multi-system structural dynamics model, the wind condition data and the blade structural dynamics model are input into the unsteady aerodynamic model to determine the aerodynamic load, and the aerodynamic load is loaded onto the flexible blade through the software platform node and fed back to the multi-system structural dynamics model to realize aerodynamic-structure coupling; the multi-system structural dynamics model is a dynamics model set of key structures of the multi-rotor multi-tower floating wind turbine; the dynamics model set of key structures includes a blade structural dynamics model, a transmission system structural dynamics model, a tower structural dynamics model and a floating platform structural dynamics model;

[0010] The wave data and the hydrodynamic coefficients in the floating platform structural dynamics model are introduced into the hydrodynamic model to determine the hydrodynamic load, and the hydrodynamic load is applied to the software platform node and fed back to the multi-system structural dynamics model;

[0011] The floating platform attitude is input into the mooring structural dynamics model to calculate the mooring cable tension, and the feedback force is input into the mooring connection point of the software platform and fed back to the multi-system structural dynamics model to realize two-way coupling feedback of platform motion and mooring tension;

[0012] Based on the multi-system structural dynamics model, the control quantity is input into the control system module to output torque set value and pitch set value, and the control quantity is fed back to the multi-system structural dynamics model; the control quantity includes rotational speed and pitch angle;

[0013] In the system level response analysis, based on the working condition configuration information, the feedback multi-system structural dynamics model, the unsteady aerodynamic model, the hydrodynamic model and the mooring structural dynamics model are unified into the Lagrange framework, and joint simulation interface is used for joint simulation running to design the multi-rotor multi-tower floating wind turbine.

[0014] In a second aspect, the application provides a computer device, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to realize the system level coupling modeling method of the multi-rotor multi-tower floating wind turbine.

[0015] In a third aspect, the present application provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the system-level coupling modeling method of the multi-rotor multi-tower floating wind turbine.

[0016] According to the specific embodiments provided in the present application, the present application has the following technical effects:

[0017] Firstly, the multi-system structural dynamics model of key components such as blades, tower and platform is established. The blades and tower are flexible bodies, which can truly reflect the structural elastic properties and dynamic response process of the components, and fully consider the feedback of structural elasticity. Secondly, by integrating the hydrodynamic model (HydroDyn) and the mooring structure dynamics model (MoorDyn), and combining the multi-system structural dynamics model, the real-time calculation of the motion response and feedback of the platform under the action of wind and wave is realized, the dynamic coupling of hydrodynamics and structure is formed, and the feedback of platform motion is fully considered. Finally, through the real-time interaction of the joint simulation interface and each model, each model including the feedback multi-system structural dynamics model, the unsteady aerodynamic model, the hydrodynamic model and the mooring structure dynamics model unified into the Lagrange framework, the dynamic feedback of the control command and the synchronous update of the system are ensured, and the response feedback of the controller is fully considered, so that a complete system dynamics model is established to design the multi-rotor multi-tower floating wind turbine.

[0018] The present application unifies the feedback multi-system structural dynamics model, the unsteady aerodynamic model, the hydrodynamic model and the mooring structure dynamics model into the Lagrange framework, and realizes the information coupling and dynamic feedback between each module through the joint simulation interface, maintains the data consistency and response coupling between each module, solves the large-scale coupling problem of fluid, structure and wake interaction, reduces the design cost and improves the design efficiency, so as to meet the whole machine level rapid evaluation and engineering iteration under multiple working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0020] Figure 1 The flowchart of the system-level coupling modeling method of the multi-rotor multi-tower floating wind turbine provided by an embodiment of the present application is shown in the figure.

[0021] Figure 2 The overall flowchart of the system-level modeling of the multi-rotor multi-tower floating wind turbine provided by an embodiment of the present application is shown in the figure.

[0022] Figure 3 A time stepping method-free vortex wake calculation flowchart is provided for an embodiment of the present application;

[0023] Figure 4 A multi-rotor multi-tower floating wind turbine is provided for an embodiment of the present application;

[0024] Figure 5 A natural frequency comparison chart is provided for an embodiment of the present application;

[0025] Figure 6 A front-rotor aerodynamic thrust comparison chart is provided for an embodiment of the present application;

[0026] Figure 7 A rear-rotor aerodynamic thrust comparison chart is provided for an embodiment of the present application;

[0027] Figure 8 A front-rear rotor power comparison chart under turbulent wind conditions is provided for an embodiment of the present application;

[0028] Figure 9 A left-right tower top horizontal thrust comparison chart under turbulent wind conditions is provided for an embodiment of the present application. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0030] In order to make the purpose, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0031] As shown in the figure, the present application provides a system-level coupling modeling method for a multi-rotor multi-tower floating wind turbine, which comprises: Figure 1

[0032] S1: Obtain parameter information of the multi-rotor multi-tower floating wind turbine; the parameter information comprises environmental information and working condition configuration information; the environmental information comprises wind condition data and wave data;

[0033] ​S2: based on the multi-system structure dynamics model, input the wind condition data and the blade structure dynamics model into the unsteady aerodynamic model to determine the aerodynamic load, and load the aerodynamic load to the flexible blade through the software platform node to feedback to the multi-system structure dynamics model to realize aerodynamic-structure coupling; the multi-system structure dynamics model is a dynamics model set of key structures of the multi-rotor multi-tower floating wind turbine; the dynamics model set of key structures includes a blade structure dynamics model, a transmission system structure dynamics model, a tower structure dynamics model and a floating platform structure dynamics model;

[0034] S3: import the wave data and the hydrodynamic coefficients in the floating platform structure dynamics model into the hydrodynamic model to determine the hydrodynamic load, and apply the hydrodynamic load to the software platform node to feedback to the multi-system structure dynamics model;

[0035] S4: input the floating platform posture into the mooring structure dynamics model to calculate the mooring cable tension, and form the feedback force input to the mooring connection point of the software platform to feedback to the multi-system structure dynamics model to realize the bidirectional coupling feedback of platform motion and mooring tension;

[0036] S5: based on the multi-system structure dynamics model, input the control quantity into the control system module to output the torque set value and the pitch set value to feedback to the multi-system structure dynamics model; the control quantity includes the rotating speed and the pitch angle;

[0037] S6: in the system level response analysis, based on the working condition configuration information, the feedback multi-system structure dynamics model, the unsteady aerodynamic model, the hydrodynamic model and the mooring structure dynamics model are unified into the Lagrange framework, and the joint simulation interface is used for joint simulation running to design the multi-rotor multi-tower floating wind turbine.

[0038] In actual application, in order to realize the collaborative modeling and dynamic feedback control of each physical subsystem of the multi-rotor multi-tower floating wind turbine, the joint simulation framework based on the multi-system platform is adopted, as shown in Figure 2 The coupling calculation relationship between the structure dynamics, aerodynamics, hydrodynamics, mooring and control system modules is constructed.

[0039] Based on the multi-body dynamics modeling platform, a modular and expandable multi-physical coupling simulation framework is constructed by integrating the aerodynamic, hydrodynamic, mooring and control system modules, and introducing the free vortex wake method to simulate the wake influence between the rotors. The method can be used for whole machine load evaluation, platform motion response analysis and control strategy comparison under the multi-rotor multi-tower structure, and improves the modeling accuracy and control analysis ability of the complex wind turbine.

[0040] In one example embodiment, the unsteady aerodynamic model comprises a free vortex wake model and an aerodynamic module, and S2 specifically comprises:

[0041] S21: inputting the wind condition data and parameters of the blade structural dynamics model into the free vortex wake model based on the multi-system structural dynamics model; the parameters of the blade structural dynamics model include air density, number of blades, blade geometry, airfoil aerodynamic characteristics, number of blade elements, and time step.

[0042] S22: calculating the front wind turbine wake using the free vortex wake model according to the wind condition data and the blade structural dynamics model by time stepping method; the wind condition data is the incoming flow speed; the front wind turbine wake is the inflow velocity field of the rear wind turbine blade at each time.

[0043] S23: inputting the inflow velocity field in time series form into the aerodynamic module to determine the aerodynamic load; the aerodynamic load is the aerodynamic force.

[0044] S24: loading the aerodynamic load onto the flexible blade through the software platform node and feeding back to the multi-system structural dynamics model to realize aerodynamic-structural coupling; the software platform is the SIMPACK platform, and the software platform node is the FE244 force element.

[0045] In one example embodiment, S22 specifically comprises:

[0046] S221: establishing an initial wake coordinate based on the calculation parameters using the equal-pitch cylindrical rigid wake; the calculation parameters include the wind condition data and the parameters of the blade structural dynamics model.

[0047] S222: calculating the front wind turbine blade inflow, attached vortex circulation, and trailing vortex circulation according to the initial wake coordinate.

[0048] S223: calculating the induced velocity at the blade element control point according to the blade inflow, the attached vortex circulation, and the trailing vortex circulation; wherein the blade element is a blade element segment formed by the discretization of the wind turbine blade; an attached vortex element is arranged at the quarter chord length of each blade element segment, and the position of the attached vortex element is the blade element control point.

[0049] S224: updating the wake shape along the azimuth angle step according to the induced velocity.

[0050] S225: calculating the specified segment surface velocity according to the geometric residual of the current time wake shape and the last period time wake shape; the specified segment surface velocity is the front wind turbine wake.

[0051] In one example embodiment, S3 specifically comprises:

[0052] S31: importing the wave data and the hydrodynamic coefficients in the frequency domain pre-computed form in the floating platform structure dynamics model into the hydrodynamic model to determine the hydrodynamic load, and applying the hydrodynamic load to the software platform node and feeding back to the multi-system structure dynamics model.

[0053] In an exemplary embodiment, S4 further comprises: based on the mooring structure dynamics model (i.e. mooring force model), mooring nodes are divided into a plurality of continuous concentrated masses in the mooring cable, and a node dynamics equation is established by considering the influencing factors of the mooring cable; the influencing factors include mass, stiffness, hydrodynamic resistance, added mass, and seabed contact.

[0054] In practical applications, the system-level coupling modeling method of the multi-wind-turbine multi-tower-column floating wind turbine of the present application is integrated into the SIMPACK platform to form a systematic module, specifically including: an information acquisition and input module, a multi-system structure dynamics model, an unsteady aerodynamic model, a hydrodynamic model, a mooring model, a control system module, and a coupling simulation interface.

[0055] The information acquisition and input module is connected to the multi-system structure dynamics model to transmit parameter information into the multi-system structure dynamics model; the multi-system structure dynamics model is connected to the unsteady aerodynamic model, the hydrodynamic model, the mooring model, and the control system module through the coupling simulation interface.

[0056] The running logic is: the information acquisition and input module obtains relevant information through software, including: wind condition data (generated by the TurbSim software), wave data (read by the HydroDyn software), and other environmental inputs; working condition configurations such as wind speed, turbulence intensity, wave height, spectral peak period, and running state (such as power generation / idling / stop) are transmitted into the system as starting conditions of the simulation model. After receiving the above environmental and running conditions, the system (including the multi-system structure dynamics model, the unsteady aerodynamic model, the hydrodynamic and mooring model, and the control system module) starts to perform response calculation and output.

[0057] The above information is input into the multi-system structure dynamics model, which serves as an intermediary for subsequent call allocation. The above wind condition data (incoming wind speed) and blade structure dynamics model (including air density, number of blades, blade geometry, airfoil aerodynamic characteristics, blade element number, time step, etc.) are input into the unsteady aerodynamic model, which performs the following specific processing to obtain aerodynamic loads. Aerodynamic loads are loaded into flexible blades through the FE237 force element defined in the SIMPACK platform, realizing aerodynamic-structural coupling. The "SIMPACK platform" is a specific software platform name that undertakes the implementation of the multi-system structure dynamics model of the multi-rotor multi-tower floating wind turbine.

[0058] At the same time, the above wave data and hydrodynamic coefficients in the floating platform structure dynamics model are imported into the hydrodynamic model (HydroDyn) in the form of frequency domain pre-computation, and the hydrodynamic load (i.e. floating platform load) is output and applied to the SIMPACK platform node (FE244 force element).

[0059] The mooring structure dynamics model inputs the platform attitude in the multi-system structure dynamics model into the mooring model (MoorDyn) to calculate the mooring cable tension, which forms a feedback force input to the mooring connection point of the SIMPACK platform, realizing two-way coupling feedback of platform motion and mooring tension.

[0060] The multi-system structure dynamics model sends control quantities (rotational speed, pitch angle) to the control system module. After processing, the control system module returns the torque set value and pitch set value to the dynamics model.

[0061] The above models are unified into the Lagrangian framework, and joint simulation is run to obtain output data such as blade root, wind wheel, tower top / tower bottom load, mooring cable tension, platform attitude, and power generation. These results can be used to evaluate the system stability, structural safety, and control strategy adjustment effect on dynamic response under different arrangements, serving the design optimization and control development of new multi-rotor multi-tower floating wind turbines.

[0062] The system takes a multi-system unified structural dynamics model as the core, and the control system module realizes information exchange and operation control of each module at a unified time step through a joint simulation interface. Each sub-module solves aerodynamic load, hydrodynamic response, cable tension and control command, and the output results are fed back to the multi-system unified structural dynamics model to drive the update of the overall system dynamic response, forming a system-level closed-loop simulation mechanism for complex working conditions. After joint simulation, output data such as blade root, wind wheel, tower top / bottom load, mooring cable tension, platform attitude and power generation can be obtained. The above results (i.e. blade root, wind wheel, tower top / bottom load, mooring cable tension, platform attitude, power generation and other data output by the system-level simulation) reflect the dynamic response characteristics of the wind turbine under different arrangement forms and operating conditions. These results can be used to evaluate the system stability, structural safety and the adjustment effect of the control strategy on the dynamic response under different arrangement forms, serving the design optimization and control development of new multi-wind wheel and multi-tower floating wind turbines. These results can provide a basis for the structural design, load evaluation and control strategy optimization of wind turbines, and thus realize the design optimization of wind turbines.

[0063] The system takes a structural dynamics model as the core, and realizes information exchange and operation control of each module at a unified time step through a joint simulation interface. Each sub-module solves aerodynamic load, hydrodynamic response, cable tension and control command, and the output results are fed back to the main structure model to drive the update of the overall system dynamic response, forming a system-level closed-loop simulation mechanism for complex working conditions.

[0064] In practical applications, the multi-system unified structural dynamics main model is as follows:

[0065] A multi-body dynamics modeling platform SIMPACK is used to establish a structural dynamics model of a multi-wind wheel and multi-tower floating wind turbine. The model includes key components such as flexible blades, inclined flexible tower, floating platform, transmission chain system, etc., supports double wind wheels and above configuration schemes, and can realize rigid-flexible coupling modeling and relative motion simulation between components. Each structural node is set as a coupling interface for interfacing with aerodynamic, hydrodynamic, mooring and control inputs.

[0066] In practical applications, the unsteady aerodynamic model (free vortex wake + AeroDyn) is as follows:

[0067] To accurately simulate the wake effect between the front and rear rotors, this application constructs a coupled unsteady aerodynamic modeling framework, consisting of a free vortex wake model (FVWM) and an AeroDyn aerodynamic module. The time-stepped FVWM model calculates the wake of the front rotor, outputting the inflow velocity field of the rear rotor blades at each moment, which serves as the input to AeroDyn. AeroDyn receives this inflow information and calculates the aerodynamic forces, which are then applied to the SIMPACK structural model via FE237 force elements. Specifically, the time-stepped FVWM model is used for unsteady aerodynamic preprocessing, and its output is used as the inflow boundary condition input for the rear rotor aerodynamic module. Figure 3 As shown, the calculation process of the free vortex wake model includes the following steps:

[0068] (1) Input calculation parameters: including air density, incoming wind speed, number of blades, blade geometry, airfoil aerodynamic characteristics, number of blade element segments, time step, etc.

[0069] (2) Calculate the initial wake coordinates: The initial wake coordinates are established using a cylindrical rigid wake with equal pitch.

[0070] (3) Calculate the inflow, attached vortex ring quantity, and trailing vortex ring quantity of the front wind turbine blade: Discretize the wind turbine blade into several blade element segments, and set attached vortex elements at one-quarter chord length of each blade element segment. Calculate the attached vortex ring quantity Γ according to the Kutta–Joukowski theorem. b :

[0071]

[0072] Among them, Γ b Where C is the attached vortex ring quantity at the blade element control point, W is the relative inflow velocity at the blade element control point, and C is the relative inflow velocity at the blade element control point. l is the lift coefficient, and c is the chord length of the blade segment.

[0073] (4) Calculate the wake-induced velocity field: The induction velocity at the leaf element control point is calculated using the Biot–Savart law:

[0074]

[0075] In the formula, Let Γ be the velocity induced by the i-th segment of the vortex at the control point; i This represents the vortex ring quantity of the i-th vortex segment. and θ represents the vectors pointing from the two endpoints of the vortex wire to the control point. iA and θ iB Let be the angle between the vectors at these two endpoints and the direction of the vortex.

[0076] To avoid singularity problem, the Vatistas vortex core model is used to modify the induced velocity:

[0077]

[0078] where r is the non-dimensional radial distance from the control point to the vortex core center, and k is the model exponent parameter. i

[0079] (5) Update the wake: according to the induced velocity above, step along the azimuth angle to get the new wake shape.

[0080] (6) Calculate the geometric convergence: calculate the geometric residual error between the wake shape at this time and the wake shape at the last cycle time, if less than a set value (such as 1x10 -4 ), it is considered to be converged, and the next step can be entered, otherwise, return to step 3.

[0081] (7) Calculate the specified section velocity: the combined inflow velocity field at the inflow of the rear wind turbine is derived in time sequence form as the input of the AeroDyn module.

[0082] In the simulation main loop, the AeroDyn module calculates the aerodynamic load of the rear wind turbine by using the BEMT theory combined with the dynamic stall model (such as the Beddoes-Leishman model) according to the inflow data. The load result is loaded to the flexible blade through the FE237 force element defined in the SIMPACK platform, realizing the aerodynamic-structural coupling.

[0083] In practical application, integrate the hydrodynamic and mooring models.

[0084] To simulate the response behavior of the floating platform under the action of wind and waves, the HydroDyn and MoorDyn modules are integrated in the present application, which are respectively used to calculate the hydrodynamic load and mooring cable tension, and are coupled with the structural dynamics model through the joint simulation interface. HydroDyn imports the hydrodynamic coefficients in the form of frequency domain precalculation, outputs the platform load, and applies it to the SIMPACK platform node (FE244 force element); MoorDyn receives the platform attitude input, calculates the mooring cable tension, and forms the feedback force input to the mooring connection point of SIMPACK, realizing the bidirectional coupling feedback of platform motion and mooring tension.

[0085] Among them, the HydroDyn module establishes a three-dimensional hydrodynamic model based on the linear potential flow theory, which is suitable for large-scale floating body structures. The water body is regarded as a non-viscous, incompressible and irrotational fluid, and the hydrodynamic response of the floating body is composed of three parts of wave excitation force, radiation damping force and static water restoring force, and the total hydrodynamic force can be expressed as:

[0086]

[0087] where F​i Hydro F represents total hydrodynamic force, F i Waves F represents wave excitation force, which is derived from the action of wave pressure on the structure surface; K ij (t) is the time-domain shock response function of hydrodynamic radiation damping, which is used to describe the wave radiation coupling effect between different degrees of freedom of the structure; is the velocity of the jth degree of freedom at the historical time τ; ρ is the density of seawater, g is the acceleration of gravity, V0 is the displacement volume of the platform, δ i3 is the Kronecker function, which is only 1 when i = 3 (vertical direction) and 0 otherwise, indicating that the static water buoyancy only exists in the vertical direction; F represents the static water restoring force stiffness matrix, which is used to describe the linear restoring force or moment generated after the displacement of the structure.

[0088] The HydroDyn module is connected to the platform node through the FE244 force element in SIMPACK, participating in the structural dynamics calculation.

[0089] At the same time, the MoorDyn module discretizes the mooring cable into a series of lumped mass nodes based on the lumped-mass method, and considers factors such as mass, stiffness, hydrodynamic resistance, added mass and seabed contact, etc., to establish the following node dynamics equation:

[0090] M n a n = F T,n - F T,n-1 + F D,n + F A，n - W n

[0091] Where M n is the lumped mass of the nth mooring node; a n is the acceleration vector of the node; F T，n and F T，n-1 are the cable tension between the current node and the adjacent upstream node; F D，n is the hydrodynamic resistance received by the node; F A，n is the added mass force; W n is the gravity of the node. The hydrodynamic resistance is further calculated by the Morison equation, C DN and C DT are the resistance coefficients in the orthogonal direction and the tangential direction, respectively, u N,i and u T,i represent the normal and tangential velocity components of the node relative to the water body, D is the diameter of the cable, C M is the added mass coefficient, and V is the displacement volume or added mass volume corresponding to each segment of the cable.

[0092] MoorDyn is run in co-simulation with SIMPACK through Simulink interface, receiving real-time platform displacement and calculating cable tension, which is fed back to the platform model to complete the coupling.

[0093] Data exchange between the above modules is realized through the co-simulation interface, and synchronization is maintained at each time step. The platform displacement and velocity are transmitted from the structural dynamics module to HydroDyn and MoorDyn, and the calculation results are applied to the structural model in the form of external excitation to realize dynamic closed-loop coupling under the combined action of wind and wave.

[0094] In practical applications, the control system module is as follows:

[0095] The wind turbine control system is built through the external platform MATLAB / Simulink, including the control system module with functions such as pitch control and torque control. The controller interacts with the multi-system in real time through the co-simulation SIMAT interface to form a complete closed-loop response process. The controller is built using MATLAB / Simulink, which interacts with the multi-system structural dynamics model through the SIMAT interface; the control quantity (torque, pitch angle) acts on the corresponding actuator in SIMPACK.

[0096] In practical applications, the environmental input and operating conditions are defined as follows:

[0097] The wind speed time series generated by TurbSim and the sea wave data defined in HydroDyn are used as environmental disturbance inputs, and parameters such as average wind speed, turbulence intensity, wave height, and spectral peak period are set; at the same time, operating conditions are specified, including normal power generation conditions, shutdown conditions, and idling conditions, etc., to construct various combined conditions for analyzing system dynamic behavior. The model is provided with environmental input and operating condition input interfaces, including wind condition data (generated by TurbSim), wave data (read by HydroDyn), etc. Environmental inputs; condition configuration such as wind speed, turbulence intensity, wave height, spectral peak period, operating state (such as power generation / idling / shutdown), etc. These inputs are transmitted into the system as starting conditions for the simulation model.

[0098] In practical applications, system response calculation and output are as follows:

[0099] In system-level response analysis, the structure, aerodynamics, hydrodynamics, and mooring subsystems are unified into the Lagrangian framework. The motion of the system generalized coordinates ξ is described by the following dynamic equation:

[0100]

[0101] wherein, ξ represents a system generalized coordinate vector, containing position and attitude information of the floating platform structure dynamics model, the blade structure dynamics model and the transmission system structure dynamics model; respectively, representing generalized velocity and generalized acceleration; M, C, K represent mass matrix, damping matrix and stiffness matrix respectively; f g is a gravity or non-structural excitation, Ψ(ξ, t) is a system geometric constraint equation, t is time, is a partial derivative of the geometric constraint equation with respect to the generalized coordinate, T represents matrix transpose, λ is a constraint Lagrange multiplier; F aero , F hydro , F moor and F ctrl are aerodynamic, hydrodynamic, mooring and control external forces respectively.

[0102] To realize the coupling calculation of the multi-modules in different coordinate systems, the following coordinate transformation formula is used to convert the force of each local subsystem into the input in the global coordinate:

[0103]

[0104] wherein, represents the force of the s-th subsystem in the local coordinate system, R s0 is a rotation matrix for converting the local coordinate system to the global coordinate system.

[0105] After the joint simulation is run, the output data such as the blade root, the wind wheel, the tower top / tower bottom load, the mooring cable tension, the platform attitude, the power generation, etc. can be obtained. These results can be used to evaluate the system stability, the structural safety and the adjustment effect of the control strategy on the dynamic response under different arrangement forms, serving the design optimization and control development of the new type of multi-wind wheel multi-tower floating wind turbine.

[0106] To verify the effectiveness and applicability of the system-level modeling and simulation method, a VX type one-base two-machine offshore floating wind turbine is constructed as a representative case based on the NREL 5MW wind turbine parameters. The unit adopts two symmetric inclined towers and a front and rear coaxial double-blade wind wheel configuration, as shown in Figure 4 , and the subsystem verification and whole-machine response analysis are carried out based on the present application.

[0107] Firstly, in terms of structural dynamics, the natural frequency results of the key components (blade, tower, transmission chain) are calculated by using the multi-body modeling method, and are compared with the wind power simulation software GH Bladed, as shown in Figure 5 . The error of the key modal natural frequency is controlled within 5%, verifying the accuracy of the established structure model, which meets the requirements of GL2010 specification.

[0108] Secondly, the time-marching free vortex wake model is introduced in the aerodynamic subsystem validation, and compared with the CFD simulation (based on RANS k-ε model) results. As shown in Figure 6 and Figure 7 , the aerodynamic thrusts of the front and rear rotors are close to each other, which verifies the effectiveness of the proposed model for the front rotor wake.

[0109] The system-level joint simulation is performed under the rated wind speed and irregular waves, and the key indicators such as wind turbine power and tower bottom thrust are output. As shown in Figure 8 , the average power generation of the rear rotor is significantly lower than that of the front rotor due to the influence of the front rotor wake. As shown in Figure 9 , the horizontal thrusts at the top of the left and right wind turbine towers have the same overall trend, but there is a certain amplitude deviation. It is speculated that the symmetric floating platform structure of the VX wind turbine makes the overall stress tend to balance, and the slight deviation of the wind direction may cause the incomplete symmetry of the load of the left and right rotors. The results show that the proposed system modeling method can accurately reflect the spatial difference of the load distribution under complex working conditions.

[0110] The overall simulation results have reasonable fluctuation amplitude and clear trend, and the system runs stably under typical working conditions, which shows that the proposed model has good coupling and simulation convergence.

[0111] The present application can effectively realize the joint modeling of the structure, aerodynamics, hydrodynamics and control behavior of the complex multi-rotor floating wind power system, and has high precision, high expandability and engineering adaptability, providing a unified and efficient computing platform for modeling analysis and performance evaluation of multi-rotor and multi-tower floating wind turbines.

[0112] The present application integrates multi-body dynamics, free vortex wake aerodynamic modeling, hydrodynamic response analysis, mooring modeling and control strategy integration, and builds a unified modeling framework with high expandability and simulation accuracy, providing systematic technical support for modeling analysis and control design of such complex structure units.

[0113] The present application can realize efficient coupling between the wind rotor, tower, platform, mooring and control system, and has good modularity, universality and engineering adaptability, meeting the needs of structural analysis, load evaluation and control strategy development in multiple scenarios.

[0114] In an example embodiment, a computer device is provided, including a memory and a processor, the memory storing a computer program, and the processor implementing the steps in the above method embodiments when executing the computer program. The computer device can be a server or a terminal. The computer device includes a processor, a memory, an input / output interface (I / O) and a communication interface. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operating system and the computer program in the non-volatile storage medium to run. The database of the computer device is configured to store to-be-processed data. The input / output interface of the computer device is configured to exchange information between the processor and external devices. The communication interface of the computer device is configured to communicate with external terminals through a network connection. The computer program is executed by the processor to implement a system-level coupling modeling method of a multi-wind-wheel multi-tower-column floating wind turbine.

[0115] In an example embodiment, a computer device is provided, including a memory and a processor, the memory storing a computer program, and the processor implementing the steps in the above method embodiments when executing the computer program.

[0116] In an example embodiment, a computer readable storage medium is provided, storing a computer program, and the computer program is executed by a processor to implement the steps in the above method embodiments.

[0117] In an example embodiment, a computer program product is provided, including a computer program, and the computer program is executed by a processor to implement the steps in the above method embodiments.

[0118] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in the present application are all information and data authorized by the user or authorized by all parties, and the collection, use and processing of related data need to comply with relevant regulations.

[0119] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by computer program instructions related to hardware, and the computer program can be stored in a non-volatile computer readable storage medium. When the computer program is executed, it can include the processes of the above-mentioned embodiments of each method. Among them, any reference to memory, database or other medium used in each embodiment provided by the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (Read-Only Memory, ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive memory (ReRAM), magnetoresistive random access memory (Magnetoresistive Random Access Memory, MRAM), ferroelectric memory (Ferroelectric Random Access Memory, FRAM), phase change memory (Phase Change Memory, PCM), graphene memory, etc. Volatile memory can include random access memory (Random Access Memory, RAM) or external cache memory, etc. As an illustration but not limitation, RAM can be in various forms, such as static random access memory (Static Random Access Memory, SRAM) or dynamic random access memory (Dynamic Random Access Memory, DRAM), etc.

[0120] The database involved in each embodiment provided by the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on blockchain, etc., without being limited thereto. The processor involved in each embodiment provided by the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., without being limited thereto.

[0121] Each technical feature of the above embodiments can be combined arbitrarily. In order to make the description simple, not all possible combinations of each technical feature in the above embodiments are described, however, as long as the combination of these technical features does not exist contradictory, it should be considered as the scope of the present application.

[0122] The principles and implementation modes of the present application are described by applying specific examples herein, and the above embodiment descriptions are only used to help understand the method and its core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed. In conclusion, the content of the present application should not be understood as a limitation.

Claims

1. A system level coupled modeling method for a multi-rotor multi-tower floating wind turbine system, characterized in that, The method comprises the following steps: acquiring parameter information of a multi-rotor multi-tower floating wind turbine; the parameter information comprises environmental information and working condition configuration information; the environmental information comprises wind condition data and wave data; based on a multi-system structural dynamics model, the wind condition data and a blade structural dynamics model are input into an unsteady aerodynamic model to determine aerodynamic load, and the aerodynamic load is loaded onto a flexible blade through a software platform node to be fed back to the multi-system structural dynamics model to realize aerodynamic-structural coupling; the multi-system structural dynamics model is a dynamics model set of key structures of a multi-rotor multi-tower floating wind turbine; the dynamics model set of key structures comprises a blade structural dynamics model, a transmission system structural dynamics model, a tower structural dynamics model and a floating platform structural dynamics model; the wave data and hydrodynamic coefficients in the floating platform structural dynamics model are introduced into a hydrodynamic model to determine hydrodynamic load, and the hydrodynamic load is applied to the software platform node to be fed back to the multi-system structural dynamics model; a floating platform attitude is input into a mooring structural dynamics model to calculate mooring cable tension and form a feedback force input into a mooring connection point of the software platform to be fed back to the multi-system structural dynamics model to realize two-way coupling feedback of platform motion and mooring tension; based on the multi-system structural dynamics model, control quantities are input into a control system module to output torque set values and pitch set values to be fed back to the multi-system structural dynamics model; the control quantities comprise rotational speed and pitch angle; in system-level response analysis, the feedback multi-system structural dynamics model, the unsteady aerodynamic model, the hydrodynamic model and the mooring structural dynamics model are unified into a Lagrange framework based on the working condition configuration information, and joint simulation is performed through a joint simulation interface to design a multi-rotor multi-tower floating wind turbine.

2. The system level coupled modeling method of a multi-rotor multi-tower floating wind turbine system as claimed in claim 1, wherein, based on a multi-system structural dynamics model, the wind condition data and a blade structural dynamics model are input into an unsteady aerodynamic model to determine aerodynamic load, and the aerodynamic load is loaded onto a flexible blade through a software platform node to be fed back to the multi-system structural dynamics model to realize aerodynamic-structural coupling, which specifically comprises: the unsteady aerodynamic model comprises a free vortex wake model and an aerodynamic module; based on a multi-system structural dynamics model, parameters of the wind condition data and the blade structural dynamics model are input into the free vortex wake model; the parameters of the blade structural dynamics model comprise air density, blade number, blade geometry, airfoil aerodynamic characteristics, blade element number and time step; a time step method is adopted to calculate the wake of a front rotor according to the wind condition data and the blade structural dynamics model by using the free vortex wake model; the wind condition data is incoming flow speed; the wake of the front rotor is the incoming flow velocity field of a rear rotor blade at each time; the incoming flow velocity field is input into the aerodynamic module in a time sequence to determine aerodynamic load; the aerodynamic load is aerodynamic force; The aerodynamic load is loaded onto the flexible blade through a software platform node, fed back to the multi-system structure dynamics model, and aerodynamic-structure coupling is realized; the software platform is a SIMPACK platform, and the software platform node is an FE237 force element.

3. The system level coupled modeling method of a multi-rotor multi-tower floating wind turbine system as claimed in claim 2, wherein, According to the wind condition data and the blade structure dynamics model, the time stepping method is adopted to calculate the pre-wind turbine wake by using a free vortex wake model, specifically including: Based on the calculation parameters, an initial wake coordinate is established by using an equal-pitch cylindrical rigid wake; the calculation parameters include the wind condition data and the parameters of the blade structure dynamics model; According to the initial wake coordinate, the inflow of the pre-wind turbine blade, the attached vortex ring moment and the trailing vortex ring moment are calculated; According to the blade inflow, the attached vortex ring moment and the trailing vortex ring moment, the induced velocity at the control point of the blade element is calculated; wherein the blade element is a blade element segment formed by the discretization of the wind turbine blade; an attached vortex element is arranged at the quarter chord length of each blade element segment, and the position of the attached vortex element is the control point of the blade element; According to the induced velocity, the wake shape is updated along the azimuth angle step; According to the wake shape at the current time and the geometric residual of the wake shape at the last period time, the specified segment surface velocity is calculated; the specified segment surface velocity is the pre-wind turbine wake.

4. The system level coupled modeling method of a multi-rotor multi-tower floating wind turbine system as claimed in claim 1, wherein, The wave data and the hydrodynamic coefficients in the floating platform structure dynamics model are introduced into the hydrodynamic model to determine the hydrodynamic load, and the hydrodynamic load is applied to the software platform node and fed back to the multi-system structure dynamics model, specifically including: The wave data and the hydrodynamic coefficients in the floating platform structure dynamics model are introduced into the hydrodynamic model in the form of frequency domain precalculation to determine the hydrodynamic load, and the hydrodynamic load is applied to the software platform node and fed back to the multi-system structure dynamics model; the software platform node is an FE244 force element.

5. The system level coupled modeling method of a multi-rotor multi-tower floating wind turbine system as claimed in claim 4, wherein, The hydrodynamic load is: where F i Hydro F is the hydrodynamic force; F i Waves F is the wave excitation force; K ij (t-τ) is the time domain impulse response function of hydrodynamic radiation damping; is the velocity of the jth degree of freedom at the history time τ; t is the current time; ρ is the seawater density; g is the gravity acceleration; V0 is the platform's displacement; δ i3 is the Kronecker function, only when i=3, δ i3 is equal to 1, and the rest is 0, δ i3 indicates that the hydrostatic buoyancy acts only in the vertical direction, i is the degree of freedom number of the structure, and takes values from 1 to 6; is the hydrostatic restoring force stiffness matrix; q j is the displacement of the jth degree of freedom at the history time τ.

6. The system level coupled modeling method of a multi-rotor multi-tower floating wind turbine system as claimed in claim 1, wherein, The floating platform attitude is input into the mooring structure dynamics model to calculate the mooring cable tension, and the feedback force is input into the mooring connection point of the software platform and fed back to the multi-system structure dynamics model to realize the bidirectional coupling feedback of platform motion and mooring tension, and the previous method further includes: Based on the mooring structure dynamics model, the mooring nodes with multiple continuous lumped masses in the mooring cable are considered, and the influencing factors of the mooring cable are considered to establish the node dynamics equation; the influencing factors include mass, stiffness, hydrodynamic resistance, added mass and seabed contact.

7. The system level coupled modeling method of a multi-rotor multi-tower floating wind turbine system as claimed in claim 6, wherein, The node dynamics equation is: M n a n = F T，n - F T,n-1 + F D,n + F A，n - W n where M n is the lumped mass of the nth mooring node; a n is the acceleration vector of the node; F T，n is the water drag force on the node; F T，n-1 are the cable tensions between the current node and the adjacent upstream nodes; F D，n is the water drag force on the node; F A，n is the added mass force; W n is the node gravity.

8. The system level coupled modeling method of a multi-rotor multi-tower floating wind turbine system as claimed in claim 1, wherein, The dynamics equation in the Lagrange framework is: Wherein, ξ is the generalized coordinate vector of the system, containing the position and attitude information of the floating platform structure dynamics model, the blade structure dynamics model and the transmission system structure dynamics model; Respectively, the first and second order time derivative, representing the generalized velocity and generalized acceleration; M, C, K represent the mass matrix, damping matrix and stiffness matrix respectively; f g Gravity or non-structural excitation, Ψ(ξ, t) is the geometric constraint equation of the system, t is the time, The partial derivative of the geometric constraint equation with respect to the generalized coordinate, T is the matrix transpose, λ is the constraint Lagrange multiplier; F aero , F hydro , F moor And F ctrl Aerodynamic load, hydrodynamic force, mooring cable tension and control external force.

9. A computer device comprising: The memory, the processor and the computer program stored on the memory and executable on the processor, characterized in that the processor executes the computer program to realize the system-level coupling modeling method of the multi-wind turbine multi-tower floating wind turbine in any one of claims 1-8.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to realize the system-level coupling modeling method of the multi-wind turbine multi-tower floating wind turbine in any one of claims 1-8.

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