Dynamically integrated wind turbine structure modeling method

Abstract

The invention relates to the technical field of wind turbine modeling, in particular to a dynamic integrated wind turbine structure modeling method, which comprises the following steps of: establishing a platform, a tower drum, a cabin and a rotor of a wind turbine in LS-DYNA, and transmitting force and motion response data between associated structures in the LS-DYNA; the geometric nonlinearity, the material nonlinearity and the contact nonlinearity of the wind turbine can be simulated, interaction keywords for data interaction with the Simulink are established in the LS-DYNA, and an aerodynamic module, a servo dynamics module and an FMU module for data interaction with the LS-DYNA are established in the Simulink. According to the method, the interaction keywords of the LS-DYNA and the FMU module of the Simulink can perform bidirectional data interaction, so that the Simulink and the LS-DYNA are combined to perform analogue simulation on the wind turbine, the dynamic integrated simulation of the wind turbine can be performed, the analysis accuracy can be ensured, and the simulation process is simpler and more controllable.

Description

Technical Field

[0001] This invention relates to the field of wind turbine modeling technology, and in particular to a dynamic integrated wind turbine structure modeling method. Background Technology

[0002] Floating wind turbines consist of components such as a platform, tower, nacelle, blades, and power system. These components differ in structural form, material properties, load type, and function. Onshore wind turbines primarily withstand threats from extreme winds, lightning, snow, and earthquakes, while offshore wind turbines must also cope with complex environmental conditions including waves, ocean currents, tsunamis, and typhoons. Therefore, their design, construction, and operation are highly complex, requiring the integration of knowledge from multiple disciplines, including aerodynamics, hydrodynamics, structural dynamics, elastoplastic mechanics, and control theory. Their high-quality and efficient development largely depends on the maturity of relevant fundamental theories and key technologies.

[0003] Studying the comprehensive performance of wind turbines is crucial for ensuring their safe operation and improving wind energy utilization efficiency. Among these studies, integrated dynamics-structure high-fidelity modeling and analysis is a core component of evaluating and optimizing wind power system performance, but it is also a highly challenging task. This method simplifies complex physical processes through physical and mathematical modeling, achieving high-precision and high-efficiency simulation of dynamic responses under complex environments from a time-domain perspective. It plays a key role in wind turbine design optimization, stability control, safety analysis, and economic evaluation.

[0004] While various nonlinear analysis software programs exist for floating wind turbines with aerodynamic-hydraulic-servo-elastic coupling, their structural modeling is largely based on modal coordinate methods or finite element beam elements, employing linear elastic material models. This makes it difficult to accurately simulate the plastic damage behavior of structures under extreme loads. Extreme dynamic disaster analysis of wind turbines involves not only geometric nonlinearity but also complex issues such as material nonlinearity and contact nonlinearity. Existing wind turbine programs face the technical challenge of simultaneously performing multiple nonlinear analyses involving geometric, material, and contact nonlinearities. LS-DYNA can perform such analyses, but it lacks the capability to analyze wind turbines. This necessitates secondary development specifically for wind turbine simulation, which is complex and uncontrollable. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing wind turbine programs in the prior art, which cannot simultaneously perform multiple nonlinear analyses such as geometric nonlinearity, material nonlinearity, and contact nonlinearity, and to provide a dynamic integrated wind turbine structure modeling method, which is applicable to horizontal axis wind turbines.

[0006] In a first aspect, the present invention provides a dynamically integrated wind turbine structure modeling method, comprising the following steps: When the wind turbine is an onshore wind turbine, an aerodynamics module, a servo dynamics module, and an FMU module that interacts with LS-DYNA are built in Simulink; In LS-DYNA, the platform, tower, nacelle, rotor, and interaction keywords for data exchange with Simulink are established; force and motion response data are transmitted between the platform and the tower, between the tower and the nacelle, and between the nacelle and the rotor; Among them, the Simulink FMU module and the LS-DYNA interaction key enable bidirectional data exchange, allowing: The aerodynamic module and the tower can transmit tower wind load and tower motion response data; The aerodynamic module and the rotor can transmit rotor wind load and rotor motion response data; The servo dynamics module and the cabin can transmit yaw speed and yaw angle. The servo dynamics module and the rotor can transmit pitch speed, rotor speed and pitch angle.

[0007] Preferably, in LS-DYNA software, the rotor modeling includes modeling the wind turbine's low-speed shaft, hub, and blades. The rotor can rotate relative to the nacelle, the low-speed shaft and hub are relatively fixed, and the blades can pitch. The pitch of the wind turbine blades is achieved through pitch revolute joints, and the rotation of the rotor is achieved through low-speed revolute joints. Both the low-speed revolute joints and the pitch revolute joints are single-degree-of-freedom revolute joints. Both the low-speed revolute joints and the pitch revolute joints are modeled using solid elements. The low-speed rotating pair includes a low-speed shaft and a nacelle. The low-speed shaft is axially horizontal, the nacelle is a fixed component, and the low-speed shaft is a rotating component. The rotation axis of the pitch rotary joint is along the length direction of the corresponding blade. The pitch rotary joint includes a rigid body A and a rigid body B. The rigid body A is a fixed component, and the rigid body B is a rotating component. The engine compartment, low-speed shaft, hub, rigid body A, and rigid body B each have independent component numbers and rigid body material numbers, and the characteristics of the rigid body are defined. The characteristics of the rigid body include the mass, moment of inertia, and center of mass position of the rigid body. The bottom of the tower is coupled to the top of the platform, the nacelle is coupled to the top of the tower, rigid body A in the pitch rotary joint is coupled to the wind turbine hub, and rigid body B in the pitch rotary joint is coupled to the root of the wind turbine blade. The single-degree-of-freedom revolute joint is reinforced by adding a spring to strengthen the constraint on degrees of freedom in directions other than the single-degree-of-freedom direction; A torsion spring unit is established on all pitch rotating joints. One node of the torsion spring unit is located on rigid body A and the other node is located on rigid body B. The torsion spring unit is used to monitor the pitch angle of the blades. The pitch angle monitored by the torsion spring unit can be output to the servo dynamics module in Simulink. A local coordinate system is established on the rigid body A of all pitch rotating pairs to monitor the load response of the blades; and a local coordinate system is established on the nacelle to monitor the load response of the nacelle.

[0008] Preferably, when establishing rotor dynamics in LS-DYNA, the hub and low-speed shaft are modeled as a whole.

[0009] Preferably, the interaction keywords are: *COSIM_FMI_INTERFACE and *COSIM_FMI_CONTROL; The engine compartment, low-speed shaft, wheel hub, rigid body A, and rigid body B have independent component numbers and rigid body material numbers, and the characteristics of the rigid body are defined by the first keyword, which is: *PART_INERTIA; The nacelle and the top of the tower are coupled by setting a second keyword, and the rigid body B in the pitch rotary joint is coupled to the root of the wind turbine blade by setting a second keyword, which is *CONSTRAINED_EXTRA_NODES_SET; The rigid body A in the pitch rotary joint is coupled to the wind turbine hub by setting a third keyword, which is: *CONSTRAINED_RIGID_BODIES; When creating the rotor, the fourth keyword is used to simulate the single-degree-of-freedom revolute joint, and the fourth keyword is *CONSTRAINED_JOINT_REVOLUTE; Motion control of the low-speed rotary joint and the pitch rotary joint is achieved by associating the fifth and sixth keywords. The fifth keyword is: *BOUNDAY_PRESCRIBED_MOTION_RIGID_LOCAL, and the sixth keyword is: *DEFINE_CURVE. By associating the seventh and eighth keywords, the pitch angle monitored by the torsion spring unit can be output to the servo dynamics module in Simulink. The seventh keyword is: *SENSOR, and the eighth keyword is: *DEFINE_CURVE_FUNCTION. The damping of the wind turbine tower and blades is set using the ninth keyword, which is: *DAMPING_FREQUENCY_RANGE_DEFORM.

[0010] Preferably, the method of strengthening the constraint on the other degrees of freedom of the single-degree-of-freedom revolute joint by adding springs is as follows: Five translational spring units are provided on both the low-speed rotary joint and the pitch rotary joint. The five translational spring units are designated as a first translational spring unit, a second translational spring unit, a third translational spring unit, a fourth translational spring unit, and a fifth translational spring unit. The first and second translational spring units are located in a plane perpendicular to the axis of rotation of the single-degree-of-freedom rotary joint, and their positions in this plane do not coincide. The third and fourth translational spring units are located in another plane on the axis of rotation of the single-degree-of-freedom rotary joint, and their positions in this plane do not coincide. The fifth translational spring unit coincides with the center line of the axis of rotation of the single-degree-of-freedom rotary joint. One node of each translational spring unit is located on the fixed part of the single-degree-of-freedom rotary joint, and the other node is located on the rotating part of the single-degree-of-freedom rotary joint.

[0011] Preferably, the first translational spring unit and the second translational spring unit provided on the same single-degree-of-freedom revolute joint are arranged perpendicularly to each other; the third translational spring unit and the fourth translational spring unit provided on the same single-degree-of-freedom revolute joint are arranged perpendicularly to each other.

[0012] Preferably, the stiffness range of the five translational spring units is 1×10⁻⁶. 9 ~1×10 10 N / m.

[0013] Preferably, in Simulink software, when modeling the servo dynamics module, a pitch angle dynamic compensation method based on time step difference is adopted to correct the pitch angle error existing in the LS-DYNA pitch rotating pair. The pitch angle dynamic compensation method based on time step difference is as follows: the pitch speed is calculated by time difference of the blade pitch angle output by LS-DYNA through Simulink, the difference is taken from the pitch speed calculated by Simulink and the negative is added, and then fed back to LS-DYNA to realize the dynamic compensation of the pitch angle.

[0014] Preferably, when the wind turbine is a fixed offshore wind turbine: a hydrodynamic module needs to be established in Simulink, wherein the Simulink FMU module and the LS-DYNA interaction keyword can perform bidirectional data interaction, so that wave load and platform motion response data can be transmitted between the hydrodynamic module and the platform. When the wind turbine is an offshore floating wind turbine: a hydrodynamic module and an anchor chain dynamics module need to be established in Simulink. There is a data transfer between the hydrodynamic module and the anchor chain dynamics module for anchor chain load and platform motion response. The Simulink FMU module and the LS-DYNA interaction keyword can perform bidirectional data interaction, so that the hydrodynamic module and the platform can transfer platform motion response and tower base internal forces.

[0015] Preferably, when modeling the platform of the offshore floating wind turbine, the platform is simulated as a rigid body; a beam element is built between the platform and the tower; the upper node of the beam element is coupled to the bottom of the tower, and the lower node of the beam element is coupled to the top of the platform.

[0016] Preferably, the upper node of the beam unit is coupled to the bottom of the tower through a tenth keyword, which is: *CONSTRAINED_NODAL_RIGID_BODY; The lower node of the beam element is coupled to the top of the platform through a second key, which is: *CONSTRAINED_EXTRA_NODES_SET; The reading of the internal forces of the beam element also needs to be achieved by associating the seventh and eighth keywords. The seventh keyword is: *SENSOR, and the eighth keyword is: *DEFINE_CURVE_FUNCTION. The motion control of the platform is achieved through the sixth and eleventh keywords. The sixth keyword is: *DEFINE_CURVE, and the eleventh keyword is: *BOUNDARY_PRESCRIBED_MOTION_RIGID.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a dynamically integrated wind turbine structural modeling method. By establishing the wind turbine platform, tower, nacelle, and rotor in LS-DYNA, and ensuring the transmission of force and motion response data between the platform and tower, between the tower and nacelle, and between the nacelle and rotor, it is possible to simulate the geometric nonlinearity, material nonlinearity, and contact nonlinearity of the wind turbine. Furthermore, by establishing interaction keywords in LS-DYNA for data exchange with Simulink, and establishing aerodynamics modules, servo dynamics modules, and an FMU module in Simulink for data exchange with LS-DYNA, bidirectional data exchange is enabled between the Simulink FMU module and the LS-DYNA interaction keywords, thereby simulating the geometric nonlinearity, material nonlinearity, and contact nonlinearity of the wind turbine. Motion response data can be transmitted to Simulink for iterative calculation of the corresponding wind load, and then fed back to the tower and rotor for simulation. The nacelle yaw angle can be transmitted to Simulink for iterative calculation of the yaw velocity, and then fed back to LS-DYNA to control the nacelle for simulation. The rotor pitch angle and turbine speed can be transmitted to Simulink for iterative calculation of the corresponding pitch speed, and then fed back to LS-DYNA to control the rotor for simulation. By jointly simulating the wind turbine using Simulink and LS-DYNA, it is possible to perform multiple nonlinear analyses such as geometric nonlinearity, material nonlinearity, and contact nonlinearity simultaneously, while ensuring the accuracy of the analysis, without the need for secondary development of LS-DYNA, making the simulation process simpler and more controllable. Attached Figure Description

[0018] Figure 1 This is a technical framework diagram of the modeling method for this invention, taking an onshore wind turbine as an example; Figure 2 This is a technical framework diagram of the modeling method for implementing the present invention, taking a fixed offshore wind turbine as an example; Figure 3 This is a technical framework diagram of the modeling method for implementing the present invention, taking a floating offshore wind turbine as an example; Figure 4 This invention provides a structural description, load composition, and coordinate system position diagram using the OC3-HywindSpar type offshore floating wind turbine as an example; Figure 4 In the image, (a) is a side view and (b) is a front and rear view; Figure 5 This is a schematic diagram of the finite element model established by the present invention using the OC3-HywindSpar type offshore floating wind turbine as an example; Figure 5In the diagram, (a) is a side view of the overall model; (b) is an enlarged detailed schematic of the engine room in (a); (c) is an enlarged detailed schematic of the translational spring in (b); (d) is an enlarged detailed schematic of the beam unit in (a); (e) is a front and rear view of the overall model; (f) is an enlarged detailed schematic of the hub in (e); (g) is an enlarged detailed schematic of the pitch rotating joint in (f); (h) is an enlarged detailed schematic of the translational spring unit in (g); and (i) is a schematic diagram of the local coordinate system on the pitch rotating joint. Figure 6 This is a schematic diagram showing the simulation comparison between the target value and the values ​​with and without dynamic compensation for pitch angle and with and without translational spring constraints. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0020] Unless otherwise specified, the terms "upper," "lower," "left," "right," "center," "inner," and "outer," etc., used in the description of specific embodiments of the present invention to indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is usually placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, and for enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0021] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," "parallel," and "coaxial" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, parallel, or coaxial. Slight tilt or deviation is permissible, as long as it does not affect the normal function of the relevant component. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," not that the structure must be perfectly horizontal; a slight tilt is acceptable. "Coaxial" means that two components are arranged as coaxially as possible, allowing them to move coaxially or approximately coaxially when their relative positions change. Alternatively, it can be simplified to mean that the corresponding device / component / element, when arranged in "horizontal," "vertical," "suspended," "parallel," or "coaxial" directions, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. For example, the deviation in the "coaxial" direction is controlled within 0.2-1mm, preferably within 0.2-0.5mm. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the solution of the present invention.

[0022] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0023] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, or nine, and can even exceed nine.

[0024] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to connection methods commonly used in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0025] Example 1 This embodiment provides a dynamic integrated wind turbine structure modeling method, including the following steps: like Figure 1As shown, when the wind turbine is an onshore wind turbine, an aerodynamics module, a servo dynamics module, and an FMU module for data interaction with LS-DYNA are built in Simulink. In LS-DYNA, a wind turbine platform, tower, nacelle, rotor, and interaction keywords for data exchange with Simulink are established. Force and motion response data (such as displacement, velocity, and acceleration) are transmitted between the platform and the tower, between the tower and the nacelle, and between the nacelle and the rotor. This enables the simulation of the geometric nonlinearity, material nonlinearity, and contact nonlinearity of the wind turbine. Among them, the Simulink FMU module and the LS-DYNA interaction key enable bidirectional data exchange, allowing: The aerodynamic module and the tower can transmit tower wind load and tower motion response data; the tower motion response data can be transmitted to Simulink for iterative calculation of the corresponding tower wind load and then fed back to LS-DYNA for tower simulation. The aerodynamic module and the rotor can transmit rotor wind load and rotor motion response data; the rotor motion response data can be transmitted to Simulink for iterative calculation of the corresponding rotor wind load and then fed back to LS-DYNA for rotor simulation. The servo dynamics module and the nacelle can transmit yaw speed and yaw angle; so that the yaw angle of the nacelle can be transmitted to Simulink for iterative calculation of yaw speed and then fed back to LS-DYNA to control the nacelle for simulation. The servo dynamics module and the rotor can transmit pitch speed, rotor speed and pitch angle, so that the rotor pitch angle and rotor speed can be transmitted to Simulink for iterative calculation to adjust the pitch speed and then fed back to LS-DYNA to control the rotor for simulation. By combining Simulink and LS-DYNA to simulate wind turbines, it is possible to simultaneously perform multiple nonlinear analyses of onshore wind turbines, including geometric nonlinearity, material nonlinearity, and contact nonlinearity, while ensuring the accuracy of the analysis. This eliminates the need for secondary development of LS-DYNA, making the simulation process simpler and more controllable.

[0026] like Figure 2 As shown, when the wind turbine is a fixed offshore wind turbine: a hydrodynamics module, an aerodynamics module, a servo dynamics module, and an FMU module for data interaction with LS-DYNA are built in Simulink; In LS-DYNA, a wind turbine platform, tower, nacelle, rotor, and interaction keywords for data exchange with Simulink are established. Force and motion response data (such as displacement, velocity, and acceleration) are transmitted between the platform and the tower, between the tower and the nacelle, and between the nacelle and the rotor. This enables the simulation of the geometric nonlinearity, material nonlinearity, and contact nonlinearity of the wind turbine. Among them, the Simulink FMU module and the LS-DYNA interaction key enable bidirectional data exchange, allowing: The aerodynamic module and the tower can transmit tower wind load and tower motion response data; the tower motion response data can be transmitted to Simulink for iterative calculation of the corresponding tower wind load and then fed back to LS-DYNA for tower simulation. The aerodynamic module and the rotor can transmit rotor wind load and rotor motion response data; the rotor motion response data can be transmitted to Simulink for iterative calculation of the corresponding rotor wind load and then fed back to LS-DYNA for rotor simulation. The servo dynamics module and the nacelle can transmit yaw speed and yaw angle; so that the yaw angle of the nacelle can be transmitted to Simulink for iterative calculation of yaw speed and then fed back to LS-DYNA to control the nacelle for simulation. The servo dynamics module and the rotor can transmit pitch speed, rotor speed and pitch angle, so that the rotor pitch angle and rotor speed can be transmitted to Simulink for iterative calculation to adjust the pitch speed and then fed back to LS-DYNA to control the rotor for simulation. The hydrodynamic module and the platform can transmit wave load and platform motion response data, so that the platform's motion response data can be transmitted to Simulink for iterative calculation of the corresponding wave load and then fed back to LS-DYNA for platform simulation. By combining Simulink and LS-DYNA to simulate wind turbines, it is possible to simultaneously perform multiple nonlinear analyses of offshore fixed wind turbines, including geometric nonlinearity, material nonlinearity, and contact nonlinearity, while ensuring the accuracy of the analysis. This eliminates the need for secondary development of LS-DYNA, making the simulation process simpler and more controllable.

[0027] like Figures 3-5As shown, when the wind turbine is an offshore floating wind turbine: a hydrodynamic module, an aerodynamic module, a servo dynamics module, an anchor chain dynamics module, and an FMU module that interacts with LS-DYNA are built in Simulink. There is a transmission of force and motion response data between the hydrodynamic module and the anchor chain dynamics module. The specific steps are as follows: S1. Establish a hydrodynamic module. The Morison equation and potential flow theory can be used to calculate the hydrodynamic loads on the wind turbine platform, and the Runge-Kutta method can be used to solve the motion equations of the wind turbine platform. In the formula: M represents the platform mass matrix of the wind turbine; C represents the platform damping matrix of the wind turbine; K represents the platform stiffness matrix of the wind turbine; X represents the platform motion response vector of the wind turbine; F represents the platform load vector of the wind turbine. S2. Establish an anchor chain dynamics module. The anchor chain dynamics module uses the open-source program Moordyn or other programs and methods to calculate the anchor chain load. There is a transmission of anchor chain load and motion response data between the hydrodynamic module and the anchor chain dynamics module, so that the anchor chain dynamics module can calculate the anchor chain load based on the motion response data of the hydrodynamic module, and the anchor chain load can be applied to the hydrodynamic module. The motion response data of the hydrodynamic module can be transmitted to the anchor chain dynamics module for iterative calculation of the anchor chain load.

[0028] S3. Establish an aerodynamics module to solve the rotor wind load based on the rotor motion response (displacement, velocity, and acceleration) and blade element momentum theory, and to solve the tower wind load based on the tower motion response (displacement, velocity, and acceleration).

[0029] S4. Establish a servo dynamics module to solve for the nacelle yaw speed based on the nacelle yaw angle and using the proportional-integral control law, and to solve for the rotor pitch speed based on the rotor pitch angle and the wind turbine speed.

[0030] S5. Establish an FMU module for data interaction between Simulink and LS-DYNA.

[0031] Build the wind turbine platform and tower in LS-DYNA. Figure 4 The tower, nacelle, and rotor are all part of the platform, which is a floating structure. Figure 4 As shown.

[0032] In LS-DYNA software, the rotor modeling includes the modeling of the wind turbine's low-speed shaft, hub, and blades. The low-speed shaft connects the rotor and the gearbox input; it directly bears the rotor's torque and rotates at a speed synchronized with the rotor, hence its low speed (typically a few to twenty revolutions per minute), such as 0-30 revolutions per minute. The rotor refers to the integral structure formed by the blades and hub. The rotor can rotate relative to the nacelle, while the low-speed shaft and hub are relatively fixed. The blades can pitch. The pitch of the wind turbine blades is achieved through pitch joints, and the rotor's rotation is achieved through low-speed joints. Both the low-speed joint and the pitch joint are modeled using solid elements and are single-degree-of-freedom rotary joints. The low-speed rotating pair includes a low-speed shaft and a nacelle. The low-speed shaft is axially horizontal (though there may be some deviation). The nacelle is a fixed component, and the low-speed shaft is a rotating component. The number of pitch rotating pairs corresponds to the number of blades, such as... Figure 4 As shown, if there are 3 blades, then there are also 3 pitch rotor pairs, with each blade corresponding to one pitch rotor pair.

[0033] When building the rotor in LS-DYNA, the hub and low-speed shaft are modeled as a whole to reduce modeling complexity and to better ensure the relative fixation of the low-speed shaft and hub, which is beneficial to the accuracy of the simulation.

[0034] The rotation axis of the pitch rotating joint is along the length direction of the corresponding blade. The pitch rotating joint includes rigid body A and rigid body B. Rigid body A is a fixed component, and rigid body B is a rotating component. The nacelle, low-speed shaft, hub, rigid body A, and rigid body B each have independent component numbers and rigid body material numbers, and their rigid body properties are defined. The nacelle, hub, rigid body A, and rigid body B each define their rigid body properties using a first keyword, where the first keyword is *PART_INERTIA. *PART_INERTIA is a keyword in LS-DYNA used to define the initial velocity of rigid body parts, and its priority is higher than the initial velocity defined by *INITIAL_VELOCITY.

[0035] The bottom of the tower and the top of the platform are coupled, enabling the transmission of force and motion response data (such as displacement, velocity, and acceleration) between the platform and the tower. The nacelle is coupled to the top of the tower, enabling the transfer of force and motion response data (such as displacement, velocity, and acceleration) between the tower and the nacelle. The coupling between the nacelle and the top of the tower is achieved by setting a second keyword, *CONSTRAINED_EXTRA_NODES_SET. In LS-DYNA, the keyword *CONSTRAINED_EXTRA_NODES_SET is used to couple some nodes of the deformable body to the rigid body. This means that during the solution process, the displacement of these nodes will be fixed or restricted, which is usually used to simulate boundary conditions or specific constraints. The node motion follows the rigid body motion. Rigid body A in the pitch revolute joint is coupled to the wind turbine hub, and rigid body B in the pitch revolute joint is coupled to the root of the wind turbine blades; this allows for the transmission of force and motion response data (such as displacement, velocity, and acceleration) between the nacelle and the rotor. Rigid body A in the pitch revolute joint is coupled to the wind turbine hub by setting a third keyword, which is *CONSTRAINED_RIGID_BODIES; Rigid body B in the pitch revolute joint is coupled to the root of the wind turbine blades by setting a second keyword. In LS-DYNA, the keyword *CONSTRAINED_RIGID_BODIES is used to couple two rigid bodies, one of which is the master rigid body and the other is the slave rigid body, with the slave rigid body following the movement of the master rigid body.

[0036] The single-degree-of-freedom revolute joint is reinforced by adding a spring to strengthen the constraint on degrees of freedom other than the single-degree-of-freedom direction. Specifically, the low-speed revolute joint and the pitch revolute joint are constructed using a fourth keyword, *CONSTRAINED_JOINT_REVOLUTE, which is used to simulate a single-degree-of-freedom hinge. However, due to the insufficient constraint capability of the fourth keyword, the motion in directions other than the rotational degree of freedom in the direction of the revolute joint axis is significant, affecting the accuracy of the simulation results. Therefore, by using a high-stiffness spring to further constrain the revolute joint, the problem of insufficient single-degree-of-freedom constraint in LS-DYNA, which affects the simulation accuracy, is solved. Specifically, five translational spring units are provided on both the low-speed rotary joint and the pitch rotary joint. These five translational spring units are designated as a first, second, third, fourth, and fifth translational spring unit. The first and second translational spring units are located in a plane perpendicular to the axis of rotation of their respective single-degree-of-freedom rotary joints, and their positions within this plane do not coincide. The third and fourth translational spring units are located in another plane on the axis of rotation of the single-degree-of-freedom rotary joint, and their positions within this plane also do not coincide. The fifth translational spring unit coincides with the center line of the axis of rotation of the single-degree-of-freedom rotary joint. Each translational spring unit has one node located on the fixed part of the single-degree-of-freedom rotary joint and another node located on the rotating part. The stiffness of the five translational spring units ranges from 1 × 10⁻⁶. 9 ~1×10 10 N / m; below this range, the limiting capability is insufficient; above this range, it will cause calculation interruption.

[0037] Motion control of the low-speed rotary joint and the pitch rotary joint is achieved by associating the fifth and sixth keywords. The fifth keyword is *BOUNDAY_PRESCRIBED_MOTION_RIGID_LOCAL, which in LS-DYNA is used to apply forced motion (displacement, velocity, or acceleration) to a rigid body in a local coordinate system, suitable for scenarios requiring rotation / translation around a custom direction or local axis. The sixth keyword is *DEFINE_CURVE; it is used to define curves or curve equations, which are commonly used in simulations to define material properties, load variations over time, etc. For example, by using curves, users can precisely control the changes in material properties under different times or conditions, which is very useful for simulating complex material behavior and dynamic loads.

[0038] A torsion spring unit is established on all pitch joints. One node of the torsion spring unit is located on rigid body A, and the other node is located on rigid body B. The torsion spring unit is used to monitor the blade pitch angle. The stiffness of the torsion spring unit is 1 N·m to ensure that the output value is equal to the actual pitch angle of the blade, avoiding the need for further conversion. In LS-DYNA, the pitch angle monitored by the torsion spring unit can be output to the servo dynamics module in Simulink by setting the seventh and eighth keywords. The seventh and eighth keywords are *SENSOR and *DEFINE_CURVE_FUNCTION, respectively. In LS-DYNA, the keyword *SENSOR is used to define a sensor. Sensors in LS-DYNA are tools used to monitor the state or parameters of specific points in the model, such as displacement, velocity, acceleration, force, and torque. By using sensors, users can obtain information about these points in real time during the simulation, which is very useful for analyzing the dynamic behavior of the model, optimizing the design, and verifying the accuracy of the model. In LS-DYNA, the keyword *DEFINE_CURVE_FUNCTION is used to define a curve function, which is very useful in simulations, especially when it is necessary to simulate how material properties change over time. For example, when simulating fatigue, creep, temperature effects, or other nonlinear behaviors of materials, curve functions can be used to define the mathematical relationships of these behaviors.

[0039] like Figure 4 As shown, floating wind turbines are subjected to environmental loads such as wind, waves, and currents. To describe the motion response of floating wind turbines, a corresponding coordinate system was established.

[0040] Furthermore, coordinate system Fixed to the ground, used to describe the overall rigid motion of a floating wind turbine.

[0041] Furthermore, coordinate system Fixed to the top of the platform, this is used to describe the displacement of the tower relative to the top of the platform, relative to the coordinate system at the initial vertical equilibrium position of the floating wind turbine. parallel.

[0042] Furthermore, coordinate system Fixed to the nacelle axis, used to monitor the rotor's motion response relative to the nacelle; Furthermore, coordinate system A rigid body A, fixed to the blade root pitch revolute joint, is used to describe the displacement of other parts of the blade relative to its root. Each blade has such a coordinate system.

[0043] When building the floating wind turbine platform in LS-DYNA, rigid body simulation is used. A beam element is created between the platform and the tower. One end of this beam element is coupled to the bottom of the tower using the tenth keyword, *CONSTRAINED_NODAL_RIGID_BODY. *CONSTRAINED_NODAL_RIGID_BODY is a keyword in LS-DYNA used to define rigid body constraints between flexible bodies (or between a flexible body and a rigid body), and the rigid body constraint relationship is achieved by specifying the set of nodes. The other end of this beam element is coupled to the top of the rigid platform using the second keyword, *CONSTRAINED_EXTRA_NODES_SET. The internal forces of the beam element are obtained using the seventh and eighth keywords and output to Simulink, so that the platform motion response of the floating wind turbine can be solved in the hydrodynamics module of Simulink. The seventh and eighth keywords are *SENSOR and *DEFINE_CURVE_FUNCTION, respectively. The sixth keyword, *DEFINE_CURVE, is used to read Simulink software to calculate the motion speed of the floating wind turbine platform, the rotation speed of the wind turbine rotor, and the pitch speed of the blades. In LS-DYNA, the eleventh keyword, *BOUNDARY_PRESCRIBED_MOTION_RIGID, is set to control the motion of the floating wind turbine platform. This eleventh keyword is used in LS-DYNA to apply forced motion boundary conditions to rigid bodies. It supports the definition of velocity, acceleration, or displacement and is often used to simulate the dynamic control motion of rigid bodies.

[0044] like Figure 5 As shown, a finite element model of the Spar type floating wind turbine is established in LS-DYNA.

[0045] Furthermore, combined Figure 5 (a) and Figure 5 (d) It can be seen that a beam element is established between the top of the platform and the bottom of the tower, and a local coordinate system is established at the top of the beam element.

[0046] Furthermore, combined Figure 5 (a) and Figure 5 (b) shows that a local coordinate system is built on the top of the nacelle, and a translational spring unit is built between the nacelle and the low-speed shaft. See the magnified details below. Figure 5 (c).

[0047] Furthermore, combined Figure 5 (e) and Figure 5 (f) shows that a pitch revolute joint is built between the blade root and the hub. A magnified view of the pitch revolute joint is shown in [f]. Figure 5 (g) and Figure 5(i), and from Figure 5 (g) The translational spring unit model was observed. A detailed enlargement of the translational spring unit is shown below. Figure 5 (h), see torsion spring Figure 5 (i). Additionally, from Figure 5 (i) shows that a local coordinate system is built on the pitch rotating pair.

[0048] It should also be noted that, Figure 5 Although each local coordinate system in the finite element model is displayed consistently as xyz, they can be identified as belonging to different coordinate systems based on their position. Furthermore, each coordinate system in the finite element model has an independent number, so there will be no error when calling the calculation.

[0049] It should also be noted that in LS-DYNA, the keywords *SET_NODE_LIST and *SET_PART_LIST are used to determine the element node number or part number to be output to the motion response in Simulink; the keyword *LOAD_NODE_SET is used to determine the element node number to which the external forces calculated in Simulink need to be loaded. The keyword *DEFINE_COORDINATE_NODES is used to establish the relevant local coordinate system.

[0050] It should also be noted that LS-DYNA requires setting interaction keywords for data exchange with Simulink (co-simulation constraints). These keywords enable bidirectional information exchange between LS-DYNA and Simulink via the FMU module. The interaction keywords are *COSIM_FMI_INTERFACE and *COSIM_FMI_CONTROL. In LS-DYNA, editing the interaction keywords *COSIM_FMI_INTERFACE and *COSIM_FMI_CONTROL determines the file names, file paths, and file contents required for interaction between Simulink and LS-DYNA.

[0051] In a preferred embodiment, the damping magnitude of the tower and blades is set using the ninth keyword, *DAMPING_FREQUENCY_RANGE_DEFORM, which makes the simulation of the structure's motion response more accurate. *DAMPING_FREQUENCY_RANGE_DEFORM is a damping option in LS-DYNA used to handle low-damped vibration problems, particularly for structural components with significant deformation. Its core function is to correct the energy dissipation characteristics in the dynamic response.

[0052] In an optional implementation, the servo dynamics module employs a time-step differential-based dynamic pitch angle compensation method to correct the pitch angle error present in the LS-DYNA pitch joint. This method involves calculating the pitch speed using Simulink by performing time-step differential calculations on the blade pitch angle output from LS-DYNA, subtracting and negating the calculated pitch speed from the calculated pitch speed in Simulink, then adding the result back to LS-DYNA to achieve dynamic pitch angle compensation. This approach addresses errors present in LS-DYNA modeling, such as… Figure 6 As shown, when there is no constraint from the translational spring element in LS-DYNA and no compensation from the dynamic pitch angle compensation method in Simulink, the pitch angle differs greatly from the target value. When there is no constraint from the translational spring element in LS-DYNA but compensation is made using the dynamic pitch angle compensation method in Simulink, the pitch angle fluctuates compared to the target value. When there is constraint from the translational spring element in LS-DYNA and compensation is made using the dynamic pitch angle compensation method in Simulink, that is, by setting the first, second, third, fourth and fifth translational spring elements and using the dynamic pitch angle compensation method, the simulation accuracy of the joint solution between LS-DYNA and Simulink is improved, making the simulation results closer to the target value.

[0053] The Simulink FMU module and the LS-DYNA interaction keywords enable bidirectional data interaction, allowing the aerodynamics module and the tower to exchange tower wind load and tower motion response data; and enabling the tower motion response data to be transmitted to Simulink for iterative calculation of the corresponding tower wind load, and then fed back to LS-DYNA for tower simulation. The aerodynamic module and the rotor can transmit rotor wind load and rotor motion response data; the rotor motion response data can be transmitted to Simulink for iterative calculation of the corresponding rotor wind load and then fed back to LS-DYNA for rotor simulation. The servo dynamics module and the nacelle can transmit yaw speed and yaw angle; so that the yaw angle of the nacelle can be transmitted to Simulink for iterative calculation of yaw speed and then fed back to LS-DYNA to control the nacelle for simulation. The servo dynamics module and the rotor can transmit pitch speed, rotor speed and pitch angle, so that the rotor pitch angle and rotor speed can be transmitted to Simulink for iterative calculation to adjust the pitch speed and then fed back to LS-DYNA to control the rotor for simulation. The hydrodynamic module and the platform can transmit platform motion response and tower base internal forces, that is, the internal forces of the beam element can be transmitted to the hydrodynamic module, and the platform in the LS-DYNA can be controlled after the motion response in the hydrodynamic module.

[0054] The integrated dynamics wind turbine structure modeling method described in this embodiment allows the load response of the low-speed shaft, the pitch angle and load response of the blades obtained from the simulation in LS-DYNA to be transmitted to Simulink for calculation along with the number and material number of each rigid body and the rigid body characteristics. Then, it is fed back to LS-DYNA for simulation, enabling it to perform multiple nonlinear analyses such as geometric nonlinearity, material nonlinearity and contact nonlinearity simultaneously, while ensuring the accuracy of the analysis.

[0055] The model of the wind turbine structure with integrated dynamics was completed based on the aforementioned method for modeling wind turbine structure with integrated dynamics. Then, following the method in the LS-DYNA manual, the *COSIM_FMI_CONTROL parameter was modified for the first time, and then the LS-DYNA solver was run to generate files for data interaction with Simulink; Then, following the method in the LS-DYNA manual, modify the *COSIM_FMI_CONTROL parameter a second time, and then run the LS-DYNA solver again to put it into a solver waiting state until the LS-DYNA solver receives the co-simulation start command issued by the FMU module in Simulink. Finally, click the FMU module in Simulink to load the data interaction file generated by LS-DYNA, and then run Simulink to start real-time co-simulation with LS-DYNA; It should be noted that Simulink typically uses a larger simulation time step, while LS-DYNA uses a smaller one. To ensure the stability of numerical calculations, the order of magnitude difference between the computation time steps of Simulink and LS-DYNA in the co-simulation process should not exceed 3.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dynamic integrated wind turbine structure modeling method, characterized in that, Includes the following steps: When the wind turbine is an onshore wind turbine, an aerodynamics module, a servo dynamics module, and an FMU module that interacts with LS-DYNA are built in Simulink; In LS-DYNA, the platform, tower, nacelle, rotor, and interaction keywords for data exchange with Simulink are established; force and motion response data are transmitted between the platform and the tower, between the tower and the nacelle, and between the nacelle and the rotor; Among them, the Simulink FMU module and the LS-DYNA interaction key enable bidirectional data exchange, allowing: The aerodynamic module and the tower can transmit tower wind load and tower motion response data; The aerodynamic module and the rotor can transmit rotor wind load and rotor motion response data; The servo dynamics module and the cabin can transmit yaw speed and yaw angle. The servo dynamics module and the rotor can transmit pitch speed, rotor speed and pitch angle.

2. The method for modeling a wind turbine structure with integrated dynamics according to claim 1, characterized in that, In LS-DYNA software, the rotor modeling includes the modeling of the wind turbine's low-speed shaft, hub, and blades. The rotor can rotate relative to the nacelle, while the low-speed shaft and hub are relatively fixed, and the blades can pitch. The pitch of the wind turbine blades is achieved through pitch revolute joints, and the rotation of the rotor is achieved through low-speed revolute joints. Both the low-speed revolute joints and the pitch revolute joints are single-degree-of-freedom revolute joints. Both the low-speed revolute joints and the pitch revolute joints are modeled using solid elements. The low-speed rotating pair includes a low-speed shaft and a nacelle. The low-speed shaft is axially horizontal, the nacelle is a fixed component, and the low-speed shaft is a rotating component. The rotation axis of the pitch rotary joint is along the length direction of the corresponding blade. The pitch rotary joint includes a rigid body A and a rigid body B. The rigid body A is a fixed component, and the rigid body B is a rotating component. The engine compartment, low-speed shaft, hub, rigid body A, and rigid body B each have independent component numbers and rigid body material numbers, and the characteristics of the rigid body are defined. The characteristics of the rigid body include the mass, moment of inertia, and center of mass position of the rigid body. The bottom of the tower is coupled to the top of the platform, the nacelle is coupled to the top of the tower, rigid body A in the pitch rotary joint is coupled to the wind turbine hub, and rigid body B in the pitch rotary joint is coupled to the root of the wind turbine blade. The single-degree-of-freedom revolute joint is reinforced by adding a spring to strengthen the constraint on degrees of freedom in directions other than the single-degree-of-freedom direction; A torsion spring unit is established on all pitch rotating joints. One node of the torsion spring unit is located on rigid body A and the other node is located on rigid body B. The torsion spring unit is used to monitor the pitch angle of the blades. The pitch angle monitored by the torsion spring unit can be output to the servo dynamics module in Simulink. A local coordinate system is established on the rigid body A of all pitch rotating pairs to monitor the load response of the blades; and a local coordinate system is established on the nacelle to monitor the load response of the nacelle.

3. The method for modeling a wind turbine structure with integrated dynamics according to claim 2, characterized in that, When creating the rotor in LS-DYNA, model the hub and low-speed shaft as a whole.

4. The method for integrated dynamics modeling of wind turbine structures according to claim 2, characterized in that, The interaction keywords are: *COSIM_FMI_INTERFACE and *COSIM_FMI_CONTROL; The engine compartment, low-speed shaft, wheel hub, rigid body A, and rigid body B have independent component numbers and rigid body material numbers, and the characteristics of the rigid body are defined by the first keyword, which is: *PART_INERTIA; The nacelle and the top of the tower are coupled by setting a second keyword, and the rigid body B in the pitch rotary joint is coupled to the root of the wind turbine blade by setting a second keyword, which is *CONSTRAINED_EXTRA_NODES_SET; The rigid body A in the pitch rotary joint is coupled to the wind turbine hub by setting a third keyword, which is: *CONSTRAINED_RIGID_BODIES; When creating the rotor, the fourth keyword is used to simulate the single-degree-of-freedom revolute joint, and the fourth keyword is *CONSTRAINED_JOINT_REVOLUTE; Motion control of the low-speed rotary joint and the pitch rotary joint is achieved by associating the fifth and sixth keywords. The fifth keyword is: *BOUNDAY_PRESCRIBED_MOTION_RIGID_LOCAL, and the sixth keyword is: *DEFINE_CURVE. By associating the seventh and eighth keywords, the pitch angle monitored by the torsion spring unit can be output to the servo dynamics module in Simulink. The seventh keyword is: *SENSOR, and the eighth keyword is: *DEFINE_CURVE_FUNCTION. The damping of the wind turbine tower and blades is set using the ninth keyword, which is: *DAMPING_FREQUENCY_RANGE_DEFORM.

5. The method for integrated dynamics modeling of wind turbine structures according to claim 4, characterized in that, The method of strengthening the constraint on other degrees of freedom of a single-degree-of-freedom revolute joint by adding springs is as follows: Five translational spring units are provided on both the low-speed rotary joint and the pitch rotary joint. The five translational spring units are designated as a first translational spring unit, a second translational spring unit, a third translational spring unit, a fourth translational spring unit, and a fifth translational spring unit. The first and second translational spring units are located in a plane perpendicular to the axis of rotation of the single-degree-of-freedom rotary joint, and their positions in this plane do not coincide. The third and fourth translational spring units are located in another plane on the axis of rotation of the single-degree-of-freedom rotary joint, and their positions in this plane do not coincide. The fifth translational spring unit coincides with the center line of the axis of rotation of the single-degree-of-freedom rotary joint. One node of each translational spring unit is located on the fixed part of the single-degree-of-freedom rotary joint, and the other node is located on the rotating part of the single-degree-of-freedom rotary joint.

6. The method for modeling a wind turbine structure with integrated dynamics according to claim 5, characterized in that, The first and second translational spring units on the same single-degree-of-freedom revolute joint are arranged perpendicularly to each other; the third and fourth translational spring units on the same single-degree-of-freedom revolute joint are arranged perpendicularly to each other.

7. The method for modeling a wind turbine structure with integrated dynamics according to claim 5, characterized in that, In Simulink software, when modeling the servo dynamics module, a dynamic compensation method for pitch angle based on time step difference is adopted to correct the pitch angle error existing in the LS-DYNA pitch rotating pair. The dynamic compensation method for pitch angle based on time step difference is as follows: Simulink calculates the pitch speed by performing time difference on the blade pitch angle output by LS-DYNA, and adds the difference and negative of the pitch speed calculated by Simulink to the calculated pitch speed. Then, the difference is fed back to LS-DYNA to achieve dynamic compensation of pitch angle.

8. A method for modeling a wind turbine structure with integrated dynamics according to any one of claims 1-7, characterized in that, When the wind turbine is a fixed offshore wind turbine: a hydrodynamic module also needs to be built in Simulink. The Simulink FMU module and the LS-DYNA interaction keyword can perform bidirectional data interaction, so that wave load and platform motion response data can be transmitted between the hydrodynamic module and the platform. When the wind turbine is an offshore floating wind turbine: a hydrodynamic module and an anchor chain dynamics module need to be established in Simulink. There is a data transfer between the hydrodynamic module and the anchor chain dynamics module for anchor chain load and platform motion response. The Simulink FMU module and the LS-DYNA interaction keyword can perform bidirectional data interaction, so that the hydrodynamic module and the platform can transfer platform motion response and tower base internal forces.

9. The method for modeling a wind turbine structure with integrated dynamics according to claim 8, characterized in that, When modeling the platform of an offshore floating wind turbine, the platform is simulated as a rigid body; a beam element is built between the platform and the tower; the upper node of the beam element is coupled to the bottom of the tower, and the lower node of the beam element is coupled to the top of the platform.

10. The method for modeling a wind turbine structure with integrated dynamics according to claim 9, characterized in that, The upper node of the beam element is coupled to the bottom of the tower through the tenth keyword, which is: *CONSTRAINED_NODAL_RIGID_BODY; The lower node of the beam element is coupled to the top of the platform through a second key, which is: *CONSTRAINED_EXTRA_NODES_SET; The reading of the internal forces of the beam element also needs to be achieved by associating the seventh and eighth keywords. The seventh keyword is: *SENSOR, and the eighth keyword is: *DEFINE_CURVE_FUNCTION. The motion control of the platform is achieved through the sixth and eleventh keywords. The sixth keyword is: *DEFINE_CURVE, and the eleventh keyword is: *BOUNDARY_PRESCRIBED_MOTION_RIGID.

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