A wind turbine multi-disaster full-coupling time-domain simulation method and system

Abstract

The application discloses a kind of wind turbine multi-disaster full coupling time domain simulation method and system, belong to offshore wind turbine simulation technical field.The method includes: obtaining input parameter, input parameter includes seismic acceleration time history, wave parameter, wind field parameter and the structural parameter of floating wind turbine;Calculate seismic equivalent load, wave load and wind load;The value of multiple load on respective original time node is resampled to the unified time node under unified integration step, and the synchronous load vector is obtained;Based on the synchronous load vector, the full coupling time domain integral solution is executed to the generalized motion equation of floating wind turbine, and the complete time domain dynamic response time history of floating wind turbine is output.The application can realize the full coupling time domain simulation of earthquake wave wind three disasters, solve the problem that multiple disaster load time steps are inconsistent, and improve the prediction accuracy of floating wind turbine dynamic response under extreme working condition.

Description

Technical Field

[0001] This invention belongs to the field of offshore wind turbine simulation technology, and relates to a multi-hazard fully coupled time-domain simulation method and system for wind turbines. Background Technology

[0002] As offshore wind power development expands from nearshore to deep-sea areas, floating wind turbines are gradually becoming the mainstream technology for deep-sea wind power development. However, deep-sea areas not only face extreme wind conditions such as typhoons but may also be affected by submarine earthquakes. Furthermore, the coupling effect of large waves and strong winds is significant under extreme sea conditions. Therefore, in practical engineering, floating wind turbines may simultaneously bear the combined effects of three hazardous loads: seismic activity, waves, and wind, posing a severe challenge to structural safety.

[0003] Currently, mainstream wind turbine simulation software both domestically and internationally, such as OpenFAST developed by the U.S. National Renewable Energy Laboratory, while possessing multiphysics coupling simulation capabilities, exhibits significant shortcomings in multi-hazard load coupling. Specifically, OpenFAST's seismic module (SubDyn / CompSub) and hydrodynamic module (HydroDyn) employ a weak coupling strategy, meaning they are coupled through data transfer after independent solving. This weak coupling approach cannot accurately capture earthquakes. wave The transient coupling effect among wind, air, and space is a concern. Furthermore, in time-domain simulations, the sampling frequency of seismic acceleration time histories, the solution step size of wave loads, and the calculation step size of aerodynamic loads can differ by two orders of magnitude. Existing methods lack effective synchronous interpolation mechanisms, leading to time alignment errors when superimposing loads. Simultaneously, the mooring system is a key component for positioning floating wind turbines, and its tension... The displacement relationship exhibits significant nonlinear characteristics, and under extreme disaster conditions, the mooring line may become slack. The phenomenon of alternating tension and tautness, even approaching the breaking tension, is often simulated using equivalent linearized spring models, which cannot capture the nonlinear stiffness abrupt changes and tension impulse effects of mooring systems. Summary of the Invention

[0004] The purpose of this invention is to provide a multi-hazard fully coupled time-domain simulation method and system for wind turbines, so as to solve the problem that existing technologies cannot capture the nonlinear stiffness mutation and tension impulse effect of mooring systems.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a fully coupled time-domain simulation method for multiple hazards in wind turbine generators, comprising the following steps: The input parameters include seismic acceleration time history, wave parameters, wind field parameters, and structural parameters of the floating wind turbine. The equivalent load of ground motion is calculated based on the original time step of the ground motion acceleration time history, the wave load is calculated based on the original time step of the wave parameters, and the wind load is calculated based on the original time step of the wind field parameters. Determine a uniform integration step size, and resample the values ​​of the seismic equivalent load, wave load and wind load at their original time nodes to a uniform time node under a uniform integration step size to obtain the synchronous load vector. Based on the synchronous load vector, the generalized equation of motion of the floating wind turbine is solved by fully coupled time-domain integration, and the complete time-domain dynamic response time history of the floating wind turbine is output.

[0006] Furthermore, the calculation of the equivalent ground motion load at the original time step based on the ground motion acceleration time history, the calculation of the wave load at the original time step based on wave parameters, and the calculation of the wind load at the original time step based on wind field parameters include:

[0007] This is the total external load vector. For wind load vector, This represents the equivalent load vector for seismic motion. The wave load vector; The wind load is calculated using an aerodynamic model based on blade element momentum theory (BEM). The aerodynamic force per unit blade span is:

[0008] in, The lift per unit span of the blade. The drag per unit span of the blade, air density, Relative wind speed, For the chord length, , For lift coefficient and drag coefficient, For the angle of attack, The spanwise infinitesimal length of the blade; The seismic motion is transmitted to the floating platform through the seabed foundation. The time history of the seismic acceleration is obtained using the added mass method. Convert to equivalent load:

[0009] in, The mass matrix of the floating platform. This represents the influence vector of seismic motion. The time history of ground motion acceleration; Wave loads are calculated using potential flow theory and Morrison's equations. The wave force acting on the structure is:

[0010] in, , These are the inertial force coefficient and the drag coefficient. For the density of water, For water particle velocity, For water particle acceleration, , For cross-sectional area and characteristic diameter, Because of the water depth, These are the vertical coordinates.

[0011] Furthermore, determining the unified integration step size involves resampling the values ​​of the equivalent seismic load, wave load, and wind load at their respective original time nodes to a unified time node with the unified integration step size to obtain the synchronous load vector, including: This is achieved through a multi-hazard load time-domain synchronous interpolation algorithm, which includes selecting the minimum value among the original time steps of the equivalent seismic load, wave load, and wind load as the unified integration step.

[0012] Furthermore, the multi-hazard load time-domain synchronous interpolation algorithm also includes: resampling the values ​​of the equivalent seismic load, wave load, and wind load at their respective original time nodes to a unified time node through cubic spline interpolation, so as to assemble the synchronous load vector; Assume the ground motion load is at the original node. The value on Then the cubic spline interpolation function satisfy:

[0013] in, A cubic spline interpolation function for interpolating the values ​​of seismic loads at the original time nodes; The first of the seismic loads One original time node; For the seismic load at the original time node Load values ​​on; This represents the maximum index value of the original time node of the seismic load; For cubic spline interpolation functions The first derivative; The first derivative value given at the endpoints of the interpolation interval; Under natural spline conditions, the second derivative at the boundary is zero; similarly, for wave loads... Wind load Perform interpolation; At a unified time point Above, assemble the synchronous load vector:

[0014] in, , , All were obtained by cubic spline interpolation; , as a unified integration step size; At a unified time point The synchronous load vector on the load, i.e., the total load after the superposition of multiple disaster loads; A unified time node is defined as follows: ,in This refers to the time step number; , , : These represent ground motion, wave, and wind loads at a unified time point. Load values ​​on; Unified integration step size, defined as ; , , : These are the original time steps for ground motion, wave load, and wind load, respectively.

[0015] Furthermore, the multi-hazard load time-domain synchronous interpolation algorithm also includes an interpolation accuracy verification step: calculating the interpolation residual at each time step, and automatically reducing the unified time step and re-performing the interpolation when the interpolation residual exceeds a set tolerance threshold.

[0016] Furthermore, the step of performing a fully coupled time-domain integral solution of the generalized equations of motion for the floating wind turbine specifically includes: At each time step within the total simulation duration, Newmark-β prediction is performed based on the system state at the previous moment, and the HHT-α modified equation of motion, which includes the piecewise polynomial nonlinear restoring force model of the mooring system, is assembled. Then, the Newton-Raphson iterative method is used to solve for the system state at the current moment.

[0017] The piecewise polynomial nonlinear restoring force model of the mooring system divides the tension-displacement relationship of the mooring line into a relaxation region, a normal working region, and a limit region, each corresponding to a different equivalent stiffness.

[0018] Furthermore, specifically: Using Newmark- Methods and HHT- An implicit integral scheme combining methods is used, and a mooring nonlinear iterative solution is embedded. (a) Newmark- Prediction Format exist The formulas for predicting displacement and velocity at time t are:

[0019] in, : at time step The predicted displacement vector; : at time step Predicted velocity vector; : at time step The acceleration vector; , , : Respectively the previous time step The displacement, velocity, and acceleration vectors are known. Unified integration step size; , Newmark integration parameters control the stability and accuracy of the algorithm; (b) HHT- High-frequency dissipation correction Introducing HHT- Corrected equations of motion:

[0020] in, The system's quality matrix; The damping matrix of the system; The system's stiffness matrix; : at time step External load vector; : at time step External load vector; The HHT parameter controls the degree of high-frequency numerical dissipation; when At that time, it degenerates into the Newmark-β method; (c) Mooring nonlinear restoring force model The nonlinear restoring force of the mooring system is modeled using a piecewise polynomial model:

[0021] in, The nonlinear restoring force generated by the mooring system is a displacement. The function; Displacement of the mooring system connection points; : Sign function, used to determine the direction of force; Displacement at the stiffness transition point between the relaxation zone and the normal working zone; Displacement at the stiffness inflection point between the normal operating range and the limit range; (d) Fully Coupled Iterative Solution Within each time step, the effective stiffness equation, which includes mooring nonlinearities, is solved using the Newton-Raphson iterative method:

[0022] The effective stiffness matrix and effective load vector are as follows:

[0023] in, For the Jacobian matrix of mooring restoring force, in the first... Updated in the next iteration; the convergence condition for the iteration is:

[0024] : No. The displacement increment vector obtained in the next iteration. To reduce convergence tolerance, : No. The payload vector at the next iteration : No. The internal force vector at the next iteration : No. Next iteration displacement increment vector norm, : No. The total displacement vector after the second iteration The norm of .

[0025] Secondly, the present invention provides a multi-hazard fully coupled time-domain simulation system for wind turbine generators, the system comprising: The parameter acquisition module is used to acquire input parameters, including seismic acceleration time history, wave parameters, wind field parameters, and structural parameters of the floating wind turbine. The original load calculation module is used to calculate the equivalent ground motion load, wave load, and wind load at their respective original time steps based on the parameters obtained by the parameter acquisition module. The time-domain synchronous interpolation module is used to determine a unified integration step size, and resample the values ​​of the equivalent seismic load, wave load and wind load at their respective original time nodes to a unified time node under a unified integration step size to obtain a synchronous load vector. The fully coupled time-domain solution module is used to perform fully coupled time-domain integral solution of the generalized motion equation of the floating wind turbine based on the synchronous load vector; and outputs the complete time-domain dynamic response time history of the floating wind turbine.

[0026] Thirdly, the present invention provides a computer device, including 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 implement the steps of the aforementioned wind turbine multi-hazard fully coupled time-domain simulation method.

[0027] Fourthly, the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the aforementioned wind turbine multi-hazard fully coupled time-domain simulation method.

[0028] Compared with the prior art, the present invention has the following technical effects: This invention provides a complete data foundation for multi-hazard fully coupled simulation by acquiring input parameters including seismic acceleration time history, wave parameters, wind field parameters, and floating wind turbine structural parameters. By calculating the equivalent seismic load at the original time step based on the seismic acceleration time history, the wave load at the original time step based on the wave parameters, and the wind load at the original time step based on the wind field parameters, it can uniformly quantify the effects of three physically different hazards into load vectors in the structural dynamics equations, expressing the combined effects of seismic motion, waves, and wind within the same mathematical framework. By determining a unified integration step size, the values ​​of the equivalent seismic load, wave load, and wind load at their respective original time nodes are resampled to a unified time node with the unified integration step size to obtain a synchronized load vector. This systematically eliminates time alignment errors caused by differences in the acquisition or calculation step sizes of different hazard load sources, ensuring precise synchronous superposition of the three loads on the time axis. By performing a fully coupled time-domain integral solution of the generalized equations of motion of a floating wind turbine based on the synchronous load vector, the complete time-domain dynamic response time history of the floating wind turbine is output. This allows the mooring nonlinear restoring force model to be embedded into an unconditionally stable implicit integral scheme, and through Newton's method... The Rafson iterative method accurately solves the nonlinear dynamic response under extreme conditions, enabling accurate prediction of the complete time-history response of floating wind turbines under extreme multi-hazard conditions. This method can be extended to the dynamic analysis of other marine engineering equipment under multi-hazard conditions, and has broad engineering application value. Attached Figure Description

[0029] Figure 1 Earthquake provided for embodiments of the present invention wave Block diagram of a wind-induced multi-hazard coupled system.

[0030] Figure 2 The flowchart of the multi-hazard time-domain synchronous interpolation algorithm provided in the embodiments of the present invention is shown.

[0031] Figure 3The flowchart for fully coupled time-domain integration provided in the embodiments of the present invention is shown.

[0032] Figure 4 This is a schematic diagram of the nonlinear response of a mooring system provided in an embodiment of the present invention.

[0033] Figure 5 The time history comparison diagram of tower top displacement and foundation shear force under typical extreme working conditions provided in the embodiments of the present invention is shown. Detailed Implementation

[0034] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0035] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0036] The present invention will now be described in further detail with reference to the accompanying drawings: Example 1, see Figure 1 In one embodiment of the present invention, a multi-hazard fully coupled time-domain simulation method for wind turbines is provided, which is used to perform numerical simulation of the fully coupled time-domain dynamic response of offshore floating wind turbines under the simultaneous action of three hazard loads: seismic motion, waves, and wind. It is applicable to the design verification of offshore floating wind turbines, safety assessment of extreme working conditions, and dynamic analysis of marine engineering equipment.

[0037] Specifically, the multi-hazard fully coupled time-domain simulation method for wind turbines of the present invention includes the following steps: S1: Obtain input parameters, including seismic acceleration time history, wave parameters, wind field parameters, and structural parameters of the floating wind turbine.

[0038] This step is used to obtain the complete set of input data necessary for performing multi-hazard fully coupled time-domain simulations, laying the data foundation for the subsequent independent calculation and synchronous coupling of each hazard load. It should be noted that the completeness and accuracy of the input parameters have a decisive impact on the reliability of the simulation results. The ground motion acceleration time history describes the change of ground motion caused by submarine earthquakes over time, usually given in discrete time series form, with each record containing a timestamp and the corresponding acceleration value. Wave parameters define the environmental conditions of ocean waves, including key elements such as significant wave height, peak period, and directional spectrum; these parameters determine the energy characteristics and propagation properties of waves. Wind field parameters characterize the wind environment in which the wind turbine operates, including information such as average wind speed at hub height, wind speed profile, and turbulence intensity. The structural parameters of the floating wind turbine cover the overall system's geometry, mass distribution, stiffness characteristics, and damping characteristics, including tower height, blade length, platform geometry, and draft. Based on these input parameters, the initial and boundary conditions of a multi-hazard coupled scenario can be comprehensively described, providing sufficient information support for establishing an accurate simulation model.

[0039] S2: Calculate the equivalent ground motion load at the original time step based on the ground motion acceleration time history, calculate the wave load at the original time step based on wave parameters, and calculate the wind load at the original time step based on wind field parameters.

[0040] This step transforms three physically distinct environmental hazards into a unified load expression for structural dynamics analysis. It's important to note that ground motion, the movement of the seabed, is transmitted to the floating platform through the foundation and mooring system; in dynamics analysis, this needs to be converted into an equivalent inertial force acting on the platform's mass. Waves are the oscillating motion of fluid particles; their effect on the structure manifests as distributed hydrodynamic pressure, requiring integration along the wetted surface of the structure to obtain the total force. Wind is the macroscopic flow of air, generating lift and drag through the aerodynamic shape of the blades, driving the impeller rotation and generating thrust on the tower. While the physical mechanisms and mathematical expressions of these three loads are completely different, they ultimately all manifest as force vectors acting on the wind turbine's structural degrees of freedom. This step calculates each load using mature theoretical models from their respective fields, ensuring high-precision physical descriptions before entering the unified coupled framework. The calculation of the equivalent load of seismic motion involves multiplying the input ground acceleration by the structural mass matrix; the calculation of wave load involves solving the velocity potential of the flow field and integrating the pressure; and the calculation of wind load involves determining the local velocity and angle of attack of the blade elements and looking up the lift and drag coefficients in tables. Based on the above calculations, accurate and complete original time history data can be provided for the subsequent synchronous superposition of multiple disaster loads.

[0041] S3: Determine a unified integration step size, resample the values ​​of the seismic equivalent load, wave load, and wind load at their respective original time nodes to a unified time node under a unified integration step size, and obtain the synchronous load vector.

[0042] In practical engineering, seismic ground acceleration records are typically acquired by seismic networks at sampling frequencies of 100 to 200 Hz, corresponding to time steps of 0.005 to 0.01 seconds. Numerical solutions for wave loads are limited by the computational cost of hydrodynamic models, with step sizes typically ranging from 0.1 to 0.5 seconds. The calculation step size for aerodynamic loads is constrained by the stability conditions of aeroelastic models, typically around 0.0125 seconds. The difference between these three step sizes can reach two orders of magnitude, and directly adding these load sequences at different time scales will inevitably introduce time alignment errors. This step determines a unified integration step size, remapping the time sequences of the three loads onto the same uniformly distributed time grid, thus ensuring that the load values ​​participating in the superposition correspond precisely in time at each simulation moment. The determination of the unified integration step size follows the principle of maintaining the highest accuracy, i.e., using the finest of the three step sizes. The resampling process uses interpolation methods to estimate the load values ​​at a unified time node based on the known load values ​​at the original discrete points. The above processing ensures that the subsequent fully coupled solution has consistency and accuracy in the time dimension.

[0043] S4: Based on the synchronous load vector, perform a fully coupled time-domain integral solution on the generalized motion equation of the floating wind turbine, and output the complete time-domain dynamic response time history of the floating wind turbine.

[0044] This step is used to solve the complete dynamic response of the floating wind turbine system within a unified time-domain framework, simultaneously considering the combined effects of structural inertial forces, damping forces, elastic restoring forces, mooring nonlinear restoring forces, and multiple external loads. It's important to note that the generalized equations of motion for a floating wind turbine are essentially a system of second-order nonlinear differential equations. The restoring force term of the mooring system exhibits significant nonlinear characteristics, making it impossible to solve using a simple linear superposition principle. This step employs a fully coupled time-domain integration strategy, treating the synchronous loads from multiple hazards as driving terms on the right-hand side of the equations and the mooring nonlinear restoring force as part of the internal force term on the left-hand side. Iterative solutions at each time step ensure consistent convergence of displacement, velocity, and acceleration. Full coupling means that no subsystem is decoupled or linearized during the solution process; instead, all physical effects are simultaneously incorporated into a complete solution framework. By integrating stepwise from the initial time to the simulation termination time, the continuous changes in displacement, velocity, acceleration, and internal forces of the components over time at each degree of freedom of the structure can be obtained—that is, the complete time-domain dynamic response time history. This timeline fully records the dynamic behavior of floating wind turbines throughout the entire disaster process and life cycle, providing the most direct basis for structural safety assessment and limit state verification.

[0045] This invention presents a fully coupled time-domain simulation method for multi-hazard wind turbines. Step S1 obtains a complete set of input parameters, including seismic acceleration time history, wave parameters, wind field parameters, and floating wind turbine structural parameters, providing comprehensive operating condition and model definition data for fully coupled multi-hazard simulation. Step S2 calculates the equivalent seismic load, wave load, and wind load at the original time steps of each load, unifying the three physically different hazards into a force vector within the same structural dynamics framework. Step S3 determines a unified integration step size and uses resampling technology to synchronize the three loads to a unified time node, systematically eliminating load superposition errors caused by time step differences. Step S4 employs a fully coupled time-domain integration solution strategy to perform nonlinear time history analysis on the generalized motion equations of the floating wind turbine driven by the synchronized load vectors, ultimately outputting a complete time-domain dynamic response time history. The above four steps are connected and work together to form a complete simulation chain from data input, load calculation, time synchronization to fully coupled solution, which breaks through the technical limitation of traditional methods that cannot simultaneously handle the transient coupling effects of three disaster loads, namely seismic motion, wave and wind, within the same simulation framework.

[0046] Example 2, in one embodiment of the present invention, provides a multi-hazard fully coupled time-domain simulation method for wind turbine generators, including: Step 1: Input the seismic acceleration time history Wave parameters (wave height, period, directional spectrum), wind field parameters (wind speed profile, turbulence intensity), and floating wind turbine structural parameters.

[0047] Step 2: Calculate the equivalent load of seismic motion separately. Wave load Wind load The values ​​on their respective original time grids.

[0048] Step 3: Execute the multi-hazard load time-domain synchronous interpolation algorithm (Section 5.2) to obtain a unified time step. Synchronous load vector .

[0049] Step 4: Initialize displacement, velocity, and acceleration vectors , , .

[0050] Step 5: For each time step (a) Execute Newmark- (a) Predicting and obtaining estimated values ​​of displacement and velocity; (b) Assembling HHT- (c) Call the mooring nonlinear restoring force model to calculate the mooring tension at the current displacement; (d) Solve the nonlinear equation using Newton-Raphson iteration to update the displacement, velocity, and acceleration; (e) Check the convergence of the iteration, and if it does not converge, return to step (c); (f) Output the dynamic response results at the current moment.

[0051] Step 6: Repeat step 5 until the simulation ends. Output the complete time-domain response time history.

[0052] Temporal coupling mathematical model of seismic motion-wave-wind load The multi-hazard time-domain coupled mathematical model established in this invention is based on the rigid body dynamics equations of a floating wind turbine, while simultaneously coupling the elastic deformation of the tower and blades. The generalized equations of motion of the system are:

[0053] in, This is the internal force vector that includes the nonlinear restoring force of the mooring. The total external load vector consists of three parts:

[0054] (a) Wind load model The wind load is modeled using an aerodynamic model based on Blade Element Momentum (BEM) theory, considering dynamic inflow effects and tower shadow effects. The aerodynamic force per unit blade span is:

[0055] in, air density, Relative wind speed, For the chord length, , For lift coefficient and drag coefficient, For the angle of attack.

[0056] (b) Seismic load model The seismic motion is transmitted to the floating platform through the seabed foundation. The time history of the seismic acceleration is obtained using the added mass method. Convert to equivalent load:

[0057] in, The mass matrix of the floating platform (including the additional water mass) This represents the influence vector of ground motion.

[0058] (c) Wave load model Wave loads are calculated using potential flow theory combined with Morrison's equations to determine wave-current forces. The wave forces acting on the structure are:

[0059] in, , These are the inertial force coefficient and the drag coefficient. For water particle velocity, , For cross-sectional area and characteristic diameter, The water is deep.

[0060] The core steps of the multi-hazard load time-domain synchronous interpolation algorithm proposed in this invention are as follows: Step 1: Determine the uniform integration step size The smallest time step among the three load sources is selected as the unified integration step size:

[0061] This strategy ensures that the accuracy of all loads represented on a uniform time grid is no less than the original accuracy.

[0062] Step 2: Cubic spline interpolation resampling For each load value at its original time node, a cubic spline interpolation function is used to resample it at a unified time node. Let the seismic load at the original time node... The value on Then the cubic spline interpolation function satisfy:

[0063] Under natural spline conditions, the boundary second derivative is zero. Similarly, for wave loads... Wind load Perform interpolation.

[0064] Step 3: Synchronous Load Vector Assembly At a unified time point Above, assemble the synchronous load vector:

[0065] in, , , All were obtained by cubic spline interpolation.

[0066] Step 4: Interpolation accuracy verification Calculate the interpolation residual at each time step to ensure that the interpolation error does not exceed the set tolerance threshold. :

[0067] When the residual exceeds the limit, the uniform time step is automatically reduced and the interpolation is re-established.

[0068] This invention uses Newmark- Methods and HHT- An implicit integral scheme combining the (Hilber-Hughes-Taylor) method and embedding a mooring nonlinear iterative solution.

[0069] (a) Newmark- Prediction Format exist The formulas for predicting displacement and velocity at time t are:

[0070] in, and For Newmark parameters, usually take... , To ensure unconditional stability.

[0071] (b) HHT- High-frequency dissipation correction To suppress high-frequency numerical oscillations, HHT- is introduced. Corrected equations of motion:

[0072] in, The HHT parameter controls the degree of high-frequency dissipation.

[0073] (c) Mooring nonlinear restoring force model The nonlinear restoring force of the mooring system is modeled using a piecewise polynomial model:

[0074] in, , , These are the equivalent stiffnesses for the relaxation region, normal operating region, and limit region, respectively. , This represents the displacement at the stiffness inflection point.

[0075] (d) Fully Coupled Iterative Solution Within each time step, the effective stiffness equation, which includes mooring nonlinearities, is solved using the Newton-Raphson iterative method:

[0076] The effective stiffness matrix and effective load vector are as follows:

[0077] in, For the Jacobian matrix of mooring restoring force, in the first... Updated in the next iteration. The convergence condition for the iteration is:

[0078] To achieve convergence tolerance .

[0079] Example 3 illustrates the specific implementation of this invention using a simulation of a 5MW semi-submersible floating wind turbine under extreme conditions of typhoon and earthquake.

[0080] (1) Fan parameters The system utilizes an NREL 5MW reference wind turbine with a blade length of 61.5 m, a hub height of 90 m, and a tower height of 77.6 m. The floating platform is a semi-submersible three-post structure with a draft of 20 m and a displacement of approximately 13,000 tons. The mooring system consists of three sets of catenary mooring lines, each approximately 850 m long.

[0081] (2) Definition of extreme operating conditions Earthquake parameters: Peak ground acceleration (PGA) = 0.4 g, design earthquake duration 30 s, artificial ground motion time history generated using Kanai-Tajimi spectrum, time step [not specified]. s.

[0082] Wave parameters: significant wave height m, spectral peak period s, using JONSWAP spectrum, wave load calculation time step s.

[0083] Wind parameters: 10-minute average wind speed at hub height m / s (typhoon condition), turbulence intensity category is Extreme Turbulence Model (ETM), aerodynamic calculation time step s.

[0084] (3) Simulation parameter settings Uniform time step: s.

[0085] Newmark parameters: , (Average acceleration method, unconditionally stable).

[0086] HHT parameters: (Introduce appropriate high-frequency dissipation).

[0087] Mooring nonlinear parameters: Stiffness in the relaxation region kN / m, working area stiffness kN / m, ultimate region stiffness kN / m, stiffness inflection point m、 m.

[0088] Iterative convergence tolerance: .

[0089] Total simulation duration: s.

[0090] (4) Simulation results Simulations using the method of this invention yielded the time histories of the six degrees of freedom motion of the floating platform, the dynamic stress time histories of the tower and blades, and the mooring line tension time histories.

[0091] Tower top displacement comparison: The maximum tower top displacement predicted by this method is 3.8 m, while the measured value is 4.0 m, with an error of 5%; the traditional weak coupling method predicts a value of 2.6 m, with an error of 35%.

[0092] Comparison of foundation shear force: The maximum foundation shear force predicted by this method is 2850 kN, while the measured value is 3000 kN, with an error of 5%; the value predicted by the traditional method is 2100 kN, with an error of 30%.

[0093] Mooring line tension comparison: This method successfully captured the tension pulse phenomenon that occurs in mooring lines under extreme working conditions (instantaneous tension reaches 60% of the breaking tension), while traditional linearization methods completely missed this phenomenon.

[0094] The above results show that the prediction accuracy of the method of the present invention is significantly better than that of existing methods under extreme multi-hazard coupled conditions.

[0095] See Figure 2 In another embodiment of the present invention, a multi-hazard fully coupled time-domain simulation system for wind turbines is provided, which can be used to implement the above-mentioned multi-hazard fully coupled time-domain simulation method for wind turbines. Specifically, the multi-hazard fully coupled time-domain simulation system for wind turbines includes: The parameter acquisition module is used to acquire input parameters, including seismic acceleration time history, wave parameters, wind field parameters, and structural parameters of the floating wind turbine. The original load calculation module is used to calculate the equivalent ground motion load, wave load, and wind load at their respective original time steps based on the parameters obtained by the parameter acquisition module. The time-domain synchronous interpolation module is used to determine a unified integration step size, and resample the values ​​of the equivalent seismic load, wave load and wind load at their respective original time nodes to a unified time node under a unified integration step size to obtain a synchronous load vector. The fully coupled time-domain solution module is used to perform fully coupled time-domain integral solution of the generalized motion equation of the floating wind turbine based on the synchronous load vector; and outputs the complete time-domain dynamic response time history of the floating wind turbine.

[0096] The modules are connected sequentially according to the direction of the simulation data flow, forming a complete data processing link. The parameter acquisition module is responsible for receiving and storing externally input multi-hazard condition definition data and wind turbine structure information, and providing all the necessary parameters to the original load calculation module. Based on the data provided by the parameter acquisition module, the original load calculation module calls the seismic load calculation submodule, wave load calculation submodule, and wind load calculation submodule respectively to independently generate the original time history sequences of the three loads. The time-domain synchronous interpolation module receives the three load time histories and their original time vectors from the original load calculation module, performs unified step size determination and cubic spline synchronous interpolation operations, and outputs a synchronous load vector sequence. The fully coupled time-domain solution module is driven by the synchronous load vector and executes Newmark in each time step. β prediction, HHT α correction, mooring nonlinear restoring force calculation and Newton's law The Rafson iterative solution ultimately outputs the complete time-domain dynamic response time history of the floating wind turbine.

[0097] All relevant content of each step involved in the aforementioned embodiments of the wind turbine multi-hazard fully coupled time-domain simulation method can be referenced from the functional description of the corresponding functional module of the wind turbine multi-hazard fully coupled time-domain simulation system in the embodiments of the present invention, and will not be repeated here.

[0098] The module division in this embodiment of the invention is illustrative and represents only one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in the various embodiments of the invention can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0099] In another embodiment of the present invention, a computer device is provided, comprising a processor and a memory. The memory stores a computer program, the computer program including program instructions, and the processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or it may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), or field-programmable gate arrays (FPGAs). The processor described in this embodiment of the invention can be used for the operation of the multi-hazard fully coupled time-domain simulation method for wind turbine generators. It is suitable for implementing one or more instructions, specifically for loading and executing one or more instructions in a computer storage medium to realize the corresponding method flow or corresponding function.

[0100] In another embodiment of the present invention, a storage medium is also provided, specifically a computer-readable storage medium (Memory). This computer-readable storage medium is a memory device in a computer device used to store programs and data. It is understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and extended storage media supported by the computer device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, this storage space also stores one or more instructions suitable for loading and execution by a processor. These instructions can be one or more computer programs (including program code). It should be noted that the computer-readable storage medium here can be high-speed RAM or non-volatile memory. Volatile memory, such as at least one disk storage device. One or more instructions stored in a computer-readable storage medium can be loaded and executed by a processor to implement the corresponding steps of the multi-hazard fully coupled time-domain simulation method for wind turbines in the above embodiments.

[0101] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can be implemented in one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs) containing computer-usable program code. The form of a computer program product implemented on ROM, optical memory, etc.

[0102] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0103] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0104] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A multi-hazard fully coupled time-domain simulation method for wind turbine generators, characterized in that, Includes the following steps: The input parameters include seismic acceleration time history, wave parameters, wind field parameters, and structural parameters of the floating wind turbine. The equivalent load of ground motion is calculated based on the original time step of the ground motion acceleration time history, the wave load is calculated based on the original time step of the wave parameters, and the wind load is calculated based on the original time step of the wind field parameters. Determine a uniform integration step size, and resample the values ​​of the seismic equivalent load, wave load and wind load at their original time nodes to a uniform time node under a uniform integration step size to obtain the synchronous load vector. Based on the synchronous load vector, the generalized equation of motion of the floating wind turbine is solved by fully coupled time-domain integration, and the complete time-domain dynamic response time history of the floating wind turbine is output.

2. The multi-hazard fully coupled time-domain simulation method for wind turbine generators according to claim 1, characterized in that, The equivalent ground motion load calculated based on the original time step using ground motion acceleration time history, the wave load calculated based on the original time step using wave parameters, and the wind load calculated based on the original time step using wind field parameters include: This is the total external load vector. Let the wind load vector be... This represents the equivalent load vector for seismic motion. The wave load vector; The wind load is calculated using an aerodynamic model based on blade element momentum theory (BEM). The aerodynamic force per unit blade span is: in, The lift per unit span of the blade. The drag per unit span of the blade, air density, Relative wind speed, For the chord length, , For lift coefficient and drag coefficient, For the angle of attack, The spanwise infinitesimal length of the blade; The seismic motion is transmitted to the floating platform through the seabed foundation. The time history of the seismic acceleration is obtained using the added mass method. Convert to equivalent load: in, The mass matrix of the floating platform. This represents the influence vector of seismic motion. The time history of ground motion acceleration; Wave loads are calculated using potential flow theory and Morrison's equations. The wave force acting on the structure is: in, , These are the inertial force coefficient and the drag coefficient. For the density of water, For water particle velocity, For water particle acceleration, , For cross-sectional area and characteristic diameter, Because of the water depth, These are the vertical coordinates.

3. The multi-hazard fully coupled time-domain simulation method for wind turbine generators according to claim 1, characterized in that, The process of determining a unified integration step size involves resampling the values ​​of the equivalent seismic load, wave load, and wind load at their original time nodes to a unified time node with the unified integration step size, resulting in a synchronous load vector. This includes: This is achieved through a multi-hazard load time-domain synchronous interpolation algorithm, which includes selecting the minimum value among the original time steps of the equivalent seismic load, wave load, and wind load as the unified integration step.

4. The multi-hazard fully coupled time-domain simulation method for wind turbine generators according to claim 3, characterized in that, The multi-hazard load time-domain synchronous interpolation algorithm further includes: resampling the values ​​of the equivalent seismic load, wave load, and wind load at their respective original time nodes to a unified time node through cubic spline interpolation, so as to assemble the synchronous load vector; Assume the ground motion load is at the original node. The value on Then the cubic spline interpolation function satisfy: in, A cubic spline interpolation function for interpolating the values ​​of seismic loads at the original time nodes; The first of the seismic loads One original time node; For the seismic load at the original time node Load values ​​on; This represents the maximum index value of the original time node of the seismic load; For cubic spline interpolation functions The first derivative; The first derivative value given at the endpoints of the interpolation interval; Under natural spline conditions, the second derivative at the boundary is zero; similarly, for wave loads... Wind load Perform interpolation; At a unified time point Above, assemble the synchronous load vector: in, , , All were obtained by cubic spline interpolation; , as a unified integration step size; At a unified time point The synchronous load vector on the load, i.e., the total load after the superposition of multiple disaster loads; A unified time node is defined as follows: ,in This refers to the time step number; , , : These represent ground motion, wave, and wind loads at a unified time point. Load values ​​on; Unified integration step size, defined as ; , , : These are the original time steps for ground motion, wave load, and wind load, respectively.

5. The multi-hazard fully coupled time-domain simulation method for wind turbine generators according to claim 4, characterized in that, The multi-hazard load time-domain synchronous interpolation algorithm also includes an interpolation accuracy verification step: calculating the interpolation residual at each time step, and automatically reducing the unified time step and re-performing the interpolation when the interpolation residual exceeds the set tolerance threshold.

6. The multi-hazard fully coupled time-domain simulation method for wind turbine generators according to claim 1, characterized in that, The steps for performing a fully coupled time-domain integral solution of the generalized equations of motion for the floating wind turbine specifically include: At each time step within the total simulation duration, Newmark-β prediction is performed based on the system state at the previous moment, and HHT-α modified equations of motion containing the piecewise polynomial nonlinear restoring force model of the mooring system are assembled. Then, the Newton-Raphson iterative method is used to solve for the system state at the current moment. The piecewise polynomial nonlinear restoring force model of the mooring system divides the tension-displacement relationship of the mooring line into a relaxation region, a normal working region, and a limit region, each corresponding to a different equivalent stiffness.

7. The multi-hazard fully coupled time-domain simulation method for wind turbine generators according to claim 5, characterized in that, Specifically: Using Newmark- Methods and HHT- An implicit integral scheme combining methods is used, and a mooring nonlinear iterative solution is embedded. (a) Newmark- Prediction Format exist The formulas for predicting displacement and velocity at time t are: in, : at time step The predicted displacement vector; : at time step Predicted velocity vector; : at time step The acceleration vector; , , : Respectively the previous time step The displacement, velocity, and acceleration vectors are known. Unified integration step size; , Newmark integration parameters control the stability and accuracy of the algorithm; (b) HHT- High-frequency dissipation correction Introducing HHT- Corrected equations of motion: in, The system's quality matrix; The damping matrix of the system; The system's stiffness matrix; : at time step External load vector; : at time step External load vector; The HHT parameter controls the degree of high-frequency numerical dissipation; when At that time, it degenerates into the Newmark-β method; (c) Mooring nonlinear restoring force model The nonlinear restoring force of the mooring system is modeled using a piecewise polynomial model: in, The nonlinear restoring force generated by the mooring system is a displacement. The function; Displacement of the mooring system connection points; : Sign function, used to determine the direction of force; Displacement at the stiffness transition point between the relaxation zone and the normal working zone; Displacement at the stiffness inflection point between the normal operating range and the limit range; (d) Fully Coupled Iterative Solution Within each time step, the effective stiffness equation, which includes mooring nonlinearities, is solved using the Newton-Raphson iterative method: The effective stiffness matrix and effective load vector are as follows: in, For the Jacobian matrix of mooring restoring force, in the first... Updated in the next iteration; the convergence condition for the iteration is: : No. The displacement increment vector obtained in the next iteration. To reduce convergence tolerance, : No. The payload vector at the next iteration : No. The internal force vector at the next iteration : No. Next iteration displacement increment vector norm, : No. The total displacement vector after the second iteration The norm of .

8. A multi-hazard fully coupled time-domain simulation system for wind turbine generators, characterized in that, The system for performing the method according to any one of claims 1 to 7, the system comprising: The parameter acquisition module is used to acquire input parameters, including seismic acceleration time history, wave parameters, wind field parameters, and structural parameters of the floating wind turbine. The original load calculation module is used to calculate the equivalent ground motion load, wave load, and wind load at their respective original time steps based on the parameters obtained by the parameter acquisition module. The time-domain synchronous interpolation module is used to determine a unified integration step size, and resample the values ​​of the equivalent seismic load, wave load and wind load at their respective original time nodes to a unified time node under a unified integration step size to obtain a synchronous load vector. The fully coupled time-domain solution module is used to perform fully coupled time-domain integral solution of the generalized motion equation of the floating wind turbine based on the synchronous load vector; and outputs the complete time-domain dynamic response time history of the floating wind turbine.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the multi-hazard fully coupled time-domain simulation method for wind turbine generators as described in any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the multi-hazard fully coupled time-domain simulation method for wind turbine generators as described in any one of claims 1 to 7.

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