A Simulation Calculation Method for Overall Load of Parallel Dual Wind Turbine Floating Wind Power Equipment

Abstract

This invention relates to the technical field of offshore floating wind power generation, and provides a method for simulating the load of a parallel dual-wind turbine floating wind turbine system. Based on the aerodynamic loads of the blades, hydrodynamic loads of the platform, tower structural deformation, blade structural deformation, and design parameters required for system control, the wind field environment is defined, and the aerodynamic loads of the two wind turbines are calculated. A load transformation matrix for the two wind turbines is constructed, and the transformed loads are added to obtain the total load vector of the two wind turbines on the platform. Based on the radiation and diffraction effects of the platform, the hydrodynamic loads and mooring restoring forces of the platform are calculated. Based on the tilt angles of the two wind turbines, the real-time coordinates, velocities, and accelerations of the blades of the two wind turbines are calculated. This method accurately calculates the nonlinear structural dynamic response of this novel wind energy conversion system under wind, wave, and current loads.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of offshore floating wind power generation, and particularly relates to a parallel double-wind-turbine floating wind power equipment whole-machine load simulation calculation method. BACKGROUND

[0002] Compared with onshore wind power, there is no land use restriction in the development of wind energy resources in deep sea system, and the ocean wind energy density is higher and the wind speed is more stable, which is the development direction of large-scale wind power equipment. Floating wind power equipment is to install conventional wind turbines on a floating platform to utilize the abundant wind energy resources in deep sea areas.

[0003] At present, floating wind turbines have entered the commercialization or commercial demonstration stage, and all adopt the mode of combining a single wind turbine with a single floating platform. Due to the harsh marine environment, in order to ensure the stable operation and structural safety of the wind turbine, the size of the floating platform is extremely large, and a plurality of anchor chains are also installed on the mooring system, resulting in high cost of floating wind power. The cost per kilowatt-hour of the demonstration of multiple floating wind turbines in China is three to six times that of fixed wind turbines. Therefore, floating wind power has not yet formed large-scale development.

[0004] In order to reduce the utilization cost of floating wind power, multiple wind turbines can be installed on one platform, and the overall cost of floating wind power can be reduced by making full use of the floating platform and the mooring system. Among them, the floating wind power equipment with two wind turbines installed in parallel has the most promising prospects. Due to the parallel installation mode, there is no significant aerodynamic interference problem between the two wind turbines, and the aerodynamic performance can be maintained at a high level.

[0005] However, the double-wind-turbine floating wind power equipment is a new type of wind power equipment, and at present, there is no very in-depth research, the main reason is that there is a lack of a reliable whole-machine load simulation calculation method that can consider the structural dynamic response coupling and cooperative control of two wind turbines.

[0006] CN111997842B discloses a tower and main machine installation method of floating double-wind-turbine wind turbine generator set, and gives the installation sequence and specific hoisting method of each structural component of this new type of floating wind power equipment, but does not explain how to calculate the platform motion and structural load of wind turbine under the action of wind wave flow load, etc.

[0007] CN113653603A discloses a double-wind-turbine automatic yaw power generation system and a yaw control method thereof, which includes a wind turbine, a platform, a mooring system and a yaw controller. The wind turbine has two wind turbines installed on the tower in an inclined manner. The whole machine is controlled by a propeller yaw device.

[0008] CN117189458A discloses a parallel double-wind-wheel wind turbine and a control method, two wind turbines rotate in opposite directions and keep a certain distance, but the invention is a fixed land wind turbine.

[0009] Although the above two inventions disclose part of the parallel double-wind-wheel wind turbine shape design scheme and some simple control method, but do not mention how to calculate the wind energy equipment load of the parallel double-wind-wheel wind turbine, and it is difficult to evaluate the load level, motion performance and power generation benefit of the floating wind power equipment of the double unit by relying on the currently disclosed technology or software, which greatly limits the development of this new type of floating wind power system. SUMMARY

[0010] The present application provides a parallel double-wind-turbine floating wind power equipment whole machine load simulation calculation method, which comprises the following steps:

[0011] Step S1: The design parameters required by the system control, such as the blade aerodynamic load of the double-wind-turbine floating wind power equipment, the platform hydrodynamic load, the tower structure deformation and the blade structure deformation, are given.

[0012] Step S2: The wind field environment is defined, the aerodynamic load of the two wind turbines is calculated, and the tower load vectors F1, M1 and F2, M2 of the two wind turbines at the tower base position are calculated according to the structural deformation of the tower.

[0013] Step S3: Based on the current time roll θ1, pitch θ2 and yaw θ3 of the double-wind-turbine floating wind power equipment platform, and the inclination angles α1 and α2 of the two wind turbines, the load transformation matrices T1 and T2 of the two wind turbines are constructed.

[0014] Step S4: The tower load vectors of the two wind turbines are transformed from the local coordinate system to the global coordinate system, the load action points are transferred from the tower base position to the intersection of the still water surface and the platform center axis, and the transformed loads are added to obtain the total load vectors F 合 、M 合 of the two wind turbines on the platform.

[0015] Step S5: According to the radiation diffraction effect of the double-wind-turbine floating wind power equipment platform, the platform hydrodynamic load and the mooring restoring force are calculated, the total load vectors F 合 、M 合 of the wind turbines on the platform are combined, the platform motion equation is established, and the displacement D, velocity V and acceleration A of the double-wind-turbine floating wind power equipment platform at the next time are calculated by the prediction-correction explicit time step method.

[0016] Step S6: The displacement D, velocity V and acceleration A vectors of the dual-wind-turbine floating wind power equipment platform are transmitted to the wind turbine structure dynamics solving module, and the real-time coordinates, velocities and accelerations of the blades of the two wind turbines are calculated according to the tilt angles of the two wind turbines.

[0017] Step S7: The dual-wind-turbine floating wind power equipment platform includes a unified control system, and the calculated top-of-tower velocities, nacelle accelerations, tower base loads, rotor speeds, power generation powers and electromagnetic torques of the two wind turbines are input into the control system according to the current time machine loads, platform motions, wind speeds and output powers, and the blade pitch angles β1 and β2 and electromagnetic torques T q1 、T q2 .

[0018] Step S8: Based on the real-time coordinates, velocities and accelerations of the blades and the blade pitch angles output by the control system, the blade aerodynamic loads are repeatedly calculated, and then the structural deformations of the blades and the tower are solved until the time-domain simulation calculation of the dual-wind-turbine floating wind power equipment machine load is completed.

[0019] Further, in step S1, the design parameters for blade aerodynamic load calculation include the chord length, twist angle and airfoil lift-drag coefficient at different radii of the blade.

[0020] The design parameters required for platform hydrodynamic load calculation include the first-order wave force, radiation damping and added mass parameters of the platform under the action of waves of different frequencies, and the static water stiffness matrix of the platform.

[0021] The design parameters required for tower structural deformation and blade structural deformation calculation include the modal shapes and corresponding damping ratios of each order modal of the blade and the tower, the sectional mass, flapwise stiffness and edgewise stiffness at different radii of the blade, and the sectional mass, flapwise stiffness and edgewise stiffness at different heights of the tower.

[0022] The design parameters required for system control mainly include the rated power, rated speed, pitch angle change gain and generator electromagnetic torque gain parameters.

[0023] Further, the wind field environment in step S2 is the variation data of the three direction components of the wind speed in the plane covering the wind wheels and towers of the two wind turbines over time, which is a turbulent wind, a steady wind or other wind types satisfying the wind shear law.

[0024] To calculate the aerodynamic loads of the two wind turbines respectively, the aerodynamic force of each wind turbine is calculated first, and the detailed process is as follows:

[0025] The blade aerodynamic force is applied to the corresponding node of the blade as a generalized active force.

[0026] The generalized elastic force of the blade and the tower is calculated, the gravity of the structures such as the blade, the tower, the cabin and the transmission system is considered, the motion equation of the whole wind turbine is solved, the acceleration of each structure is obtained, and the load at different sections of the tower structure is calculated.

[0027] The load vectors F1, M1 and F2, M2 of the two wind turbines in the local coordinate system at the tower base position are obtained through the above process respectively; each vector includes three elements, which respectively represent the load in the x, y and z directions in the space coordinate system.

[0028] Further, the load transformation matrices T1 and T2 of the two wind turbines are obtained in step S3, and the load transformation matrices are respectively:

[0029]

[0030] In the formula, θ1, θ2 and θ3 are the roll, pitch and yaw of the platform respectively.

[0031] Further, in step S4, the tower base load vectors of the two wind turbines are transformed from the local coordinate system to the global coordinate system, and the load application points are transferred from the tower base to the intersection point of the still water surface and the center axis of the platform. The specific method is:

[0032]

[0033] In the formula, T1 -1 and are the inverse matrices of the load transformation matrices T1 and T2 respectively, and L1 and L2 are the position vectors from the tower base position of the wind turbine model 1 and the wind turbine model 2 to the position of the intersection point of the still water surface and the center axis of the platform.

[0034] Further, the platform motion equation at t time in step S5 is:

[0035]

[0036] In the formula, m is the platform mass and the added mass matrix corresponding to the wave frequency; c is the viscous correction damping matrix; k is the platform still water stiffness matrix, h(t) is the acceleration impulse function matrix at t time, and the platform radiation damping force is calculated in the form of convolution; F 水 (t) is the water dynamics of the platform, including the action of waves and currents; F 系泊 (t) is the mooring restoring force; F 风电机组 (t) is the total load of the two wind turbines on the platform; the right side of the equation is a 1x6 vector, F 风电机组 (t) includes F 合 , M 合 ;

[0037] In which, h(t) is expressed as:

[0038]

[0039] In the formula, B is the radiation damping of the platform under the action of waves with frequency ω.

[0040] Furthermore, taking wind direction as the perspective, the wind turbine on the left is model 1, and the wind turbine on the right is model 2. In step S6, when transferring the platform displacement, velocity, and acceleration vectors to the wind turbine structural dynamics solution part, it is necessary to subtract the tilt angle α1 from the roll of wind turbine model 1, while adding the tilt angle α2 to the roll of wind turbine model 2.

[0041] Furthermore, in step S8, the fourth-order Adams-Bashforth-Moulton prediction-correction time integration method is used, and the structural dynamics of the blades and towers of the two wind turbines are solved once in both the prediction and correction steps.

[0042] Compared with the prior art, the present invention has the following advantages:

[0043] This invention can accurately calculate the nonlinear structural dynamic response of this novel wind energy conversion system under wind, wave, and current loads, taking into account the complex interactions between the floating platform, mooring system, and wind turbine.

[0044] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 The specific steps of a simulation calculation method for the overall load of a parallel dual-wind turbine floating wind power equipment are shown.

[0047] Figure 2 The diagram shows the structure of a parallel dual-wind turbine floating wind power system.

[0048] Wherein: 1 is wind turbine model 1; 2 is wind turbine model 2; 3 is still water surface; 4 is floating platform; 5 is tension leg mooring system; 6 is platform center of gravity;

[0049] Figure 3 (a) shows a schematic diagram of the calculation results of the platform motion of a 5MW+5MW dual wind turbine floating wind power equipment using a simulation calculation method for the whole machine load of a parallel dual wind turbine floating wind power equipment.

[0050] Figure 3 (b) shows a schematic diagram of the calculation results of the platform motion of a 5MW+5MW dual wind turbine floating wind power equipment using the CFD method for the overall load of the parallel dual wind turbine floating wind power equipment.

[0051] Figure 4 This paper presents a simulation calculation method for the overall load of a parallel dual-wind turbine floating wind power equipment and a schematic diagram of the time consumption of the CFD calculation method.

[0052] Figure 5 (a) shows a comparison of the rotor speeds of a parallel double wind turbine floating wind power equipment under different control states of two wind turbines in turbulent wind conditions.

[0053] Figure 5 (b) shows a comparison of the paddle pitch angles of parallel dual-wind turbine floating wind power equipment under different control states of two wind turbines in turbulent wind conditions.

[0054] Figure 6 (a) shows a comparison of the wind turbine power of a parallel double wind turbine floating wind power equipment under different control states of two wind turbines in turbulent wind conditions.

[0055] Figure 6 (b) shows a comparison of the front and rear displacement of the tower top of a parallel double wind turbine floating wind power equipment under different control states of two wind turbines in turbulent wind conditions.

[0056] Figure 6 (c) shows a comparison of the out-of-plane bending moment of the tower base of a parallel double wind turbine floating wind power equipment under different control states of two wind turbines in turbulent wind conditions.

[0057] Figure 7 (a) shows a schematic diagram of the platform pitch change of a floating wind power equipment with variable pitch and variable speed dual wind turbines under turbulent wind conditions.

[0058] Figure 7 (b) shows a schematic diagram of the platform sway changes of a floating wind power equipment with variable pitch and speed control of a wind turbine under turbulent wind conditions. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] Currently available technologies or software are insufficient to assess the load level, motion performance, and power generation efficiency of dual-unit floating wind turbines, which greatly limits the development of new floating wind power systems.

[0061] While existing technologies disclose some external design schemes and simple control methods for parallel dual-rotor wind turbine units, they do not mention how to calculate the overall load of the wind power equipment for parallel dual-rotor wind turbine units.

[0062] This invention can accurately calculate the nonlinear structural dynamic response of this novel wind energy conversion system under wind, wave, and current loads, taking into account the complex interactions between the floating platform, mooring system, and wind turbine.

[0063] like Figures 1-2 As shown, this invention discloses a method for simulating and calculating the overall load of a parallel dual-wind turbine floating wind power system. The method includes:

[0064] Step S1: Provide the aerodynamic loads on the blades, hydrodynamic loads on the platform, tower structural deformation, and blade structural deformation of the dual-wind turbine floating wind power equipment, as well as the design parameters required for system control.

[0065] Step S2: Define the wind farm environment, calculate the aerodynamic loads of the two wind turbines, and calculate the tower load vectors F1, M1 and F2, M2 of the two wind turbines at the tower base location based on the structural deformation of the tower.

[0066] Step S3: Based on the current roll θ1, pitch θ2 and yaw θ3 of the dual-wind turbine floating wind power equipment platform, and the tilt angles α1 and α2 of the two wind turbines, construct the load transformation matrices T1 and T2 of the two wind turbines.

[0067] Step S4: Transform the tower load vectors of the two wind turbines from the local coordinate system to the global coordinate system, and transfer the load application point from the tower base to the intersection of the still water surface and the platform's central axis. Add the transformed loads to obtain the total load vector F of the two wind turbines on the platform. 合 M 合 .

[0068] Step S5: Based on the radiation and diffraction effect of the dual-wind turbine floating wind power equipment platform, calculate the platform's hydrodynamic load and mooring restoring force, and combine this with the total load vector F of the wind turbines on the platform. 合 M 合 The platform motion equations are established, and the displacement D, velocity V, and acceleration A of the dual-wind turbine floating wind power equipment platform at the next moment are calculated using the predictive-corrected explicit time stepping method.

[0069] Step S6: Transfer the displacement D, velocity V, and acceleration A vectors of the dual-wind turbine floating wind power equipment platform to the wind turbine structural dynamics solution module. Calculate the real-time coordinates, velocity, and acceleration of the blades of the two wind turbines based on their tilt angles.

[0070] Step S7: The dual-wind turbine floating wind power equipment platform includes a unified control system. Based on the current total load, platform movement, wind speed, and output power, the calculated tower top speed, nacelle acceleration, tower base load, rotor speed, power generation, and electromagnetic torque of the two wind turbines are input into the control system. According to the algorithm of the control system, the blade pitch angles β1 and β2 and the electromagnetic torque T of the two wind turbines are output. q1 T q2 .

[0071] Step S8: Based on the real-time coordinates, velocity, and acceleration of the blades, as well as the blade pitch angle output by the control system, repeatedly calculate the aerodynamic load on the blades, and then solve for the structural deformation of the blades and the structural deformation of the tower, until the time-domain simulation calculation of the load of the entire floating wind power equipment with dual wind turbine units is completed.

[0072] Furthermore, the dual-wind turbine floating wind power equipment described in step S1 includes a floating platform, a single-point mooring system, and two wind turbines. The floating platform 4 has a central pillar, the top of which extends a certain distance above the still water surface 3, generally not less than twice the wave height in extreme marine environments. The tension leg mooring system 5 has its cable guide hole located below the platform's center of gravity 6, employing a tensioned tendon design. The connection point between the tension leg mooring system 5 and the floating platform 4 can rotate freely within a 360-degree range, allowing the floating platform 4 to freely face the wind. Two identical wind turbines are placed symmetrically side-by-side on the central pillar of the floating platform 4, rotating in opposite directions. The angles between the two wind turbines and the platform's central axis are the same, and the hub distance between the two tilted wind turbines is not less than 1.2 times the rotor diameter.

[0073] Furthermore, in step S1, the design parameters used for calculating the aerodynamic load on the blade include the chord length, twist angle, and airfoil lift-drag coefficient at different radii of the blade.

[0074] The design parameters required for calculating the hydrodynamic loads of the platform include the first-order wave force, radiation damping, and additional mass parameters of the platform under wave action at different frequencies, as well as the hydrostatic stiffness matrix of the platform.

[0075] The design parameters required for calculating the deformation of the tower structure and the blade structure include the mode shapes and corresponding damping ratios of each mode of the blade and the tower, the cross-sectional mass, flapping stiffness and sway stiffness at different radii of the blade, and the cross-sectional mass, flapping stiffness and sway stiffness at different heights of the tower.

[0076] The design parameters required for system control mainly include rated power, rated speed, pitch angle variation gain, and generator electromagnetic torque gain parameters.

[0077] Furthermore, the wind field environment in step S2 is the time-varying data of the three directional components of the wind speed in the plane covering the rotors and towers of the two wind turbines. This wind field is turbulent wind, steady-state wind, or other wind types that satisfy the wind shear law.

[0078] The aerodynamic loads of the two wind turbines are calculated using the generalized dynamic inflow method and blade element momentum theory. First, the aerodynamic forces of each wind turbine must be calculated. The detailed calculation process is as follows:

[0079] (1) Based on the defined wind field environment data, the real-time inflow velocity at each section of the wind turbine blade is obtained as the boundary condition. The velocity potential flow equation of the wind turbine plane is established based on the generalized dynamic inflow method to obtain the induced velocity of the wind turbine plane.

[0080] (2) Based on the rotor speed and induction, determine the velocity triangle at each section of the blade and calculate the actual angle of attack of that section;

[0081] (3) Based on the airfoil lift and drag coefficients provided in step S1, retrieve the lift coefficient and drag coefficient at the corresponding angle of attack, and calculate the aerodynamic force of the blade section using the blade element theory.

[0082] (4) The aerodynamic forces of each blade section are superimposed to obtain the aerodynamic forces of the entire wind turbine.

[0083] The aerodynamic forces acting on the blades and the corresponding nodes of the blades are taken as generalized active forces.

[0084] Calculate the generalized elastic forces of the blades and tower, considering the gravity of structures such as the blades, tower, nacelle, and transmission system, solve the motion equations of the entire wind turbine, obtain the acceleration of each structure, and calculate the loads at different sections of the tower structure.

[0085] The above process is used to obtain the load vectors F1, M1 and F2, M2 of the two wind turbines in the local coordinate system at the tower base location. Each vector includes three elements, which represent the loads in the x, y and z directions in the spatial coordinate system.

[0086] Further, in step S3, the load transformation matrices T1 and T2 of the two wind turbine units are obtained, and the load transformation matrices are as follows:

[0087]

[0088] In the formula, θ1, θ2 and θ3 are the platform's roll, pitch and yaw, respectively.

[0089] Furthermore, the specific method for transforming the load vectors of the two wind turbine tower bases from the local coordinate system to the global coordinate system in step S4, and for transferring the load application point from the tower base to the intersection of the still water surface and the platform's central axis, is as follows:

[0090]

[0091] In the formula, T1 -1 and L1 and L2 are the inverse matrices of the load transformation matrices T1 and T2, respectively, and L1 and L2 are the position vectors from the tower base position of wind turbine model 1 and wind turbine model 2 to the intersection of the still water surface and the central axis of the platform.

[0092] Furthermore, the platform motion equation at time t in step S5 is:

[0093]

[0094] In the formula, m is the platform mass and the additional mass matrix corresponding to the wave frequency; c is the viscous corrected damping matrix; k is the platform hydrostatic stiffness matrix; h(t) is the acceleration impulse function matrix at time t, and the platform radiation damping force is calculated by convolution; F 水 (t) represents the hydrodynamic forces acting on the platform, including the effects of waves and ocean currents; F 系泊 (t) represents the mooring restoring force; F 风电机组 (t) represents the total load on the platform from the two wind turbines; the right side of the equation is a 1×6 vector, F 风电机组 (t) includes F 合 M 合 ;

[0095] Where h(t) is represented as:

[0096]

[0097] In the formula, B represents the radiation damping of the platform under wave action at frequency ω. The explicit time-stepping method for solving the platform's motion equations can be the Newton-Rapson, Newmark-β, Generalized-α, fourth-order Runge-Kutta, or fourth-order Adams-Bashforth-Moulton method.

[0098] Furthermore, taking wind direction as the perspective, the wind turbine on the left is model 1, and the wind turbine on the right is model 2. In step S6, when transferring the platform displacement, velocity, and acceleration vectors to the wind turbine structural dynamics solution part, it is necessary to subtract the tilt angle α1 from the roll of wind turbine model 1, while adding the tilt angle α2 to the roll of wind turbine model 2.

[0099] Furthermore, the control commands for the blade pitch angle and generator electromagnetic torque of the two wind turbines in step S7 are calculated based on the state space of the entire floating wind power equipment. Specifically, the control closed loop of wind turbine model 1 considers the rotor thrust, tower vibration velocity, nacelle vibration acceleration, generator power, and tower base load of wind turbine model 2. The control closed loop of wind turbine model 2 also considers the relevant response parameters of wind turbine model 1. Both control closed loops consider the platform's motion state, including displacement, velocity, and acceleration.

[0100] Furthermore, in step S8, the fourth-order Adams-Bashforth-Moulton prediction-correction time integration method is used, and the structural dynamics of the blades and towers of the two wind turbines are solved once in both the prediction and correction steps.

[0101] Verification Example

[0102] Verification Example 1, such as Figures 3-4 As shown, to verify that the calculation method proposed in this invention can consider the full coupling effect of parallel dual-wind turbine floating wind power equipment, including the coupling effect of the two wind turbines with the platform and mooring, as well as the coupling effect of the whole machine's aerodynamics-hydraulics-servo-elasticity, two NREL 5MW wind turbines were installed on the OOStar floating platform to form a 10MW parallel dual-wind turbine floating wind power equipment. First, the sway and pitch of the platform at different wind speeds calculated by this method and the traditional CFD method were compared, and the results are as follows. Figure 2 As shown, the computation time of the two methods is compared, and the results are as follows. Figure 3 As shown, the results obtained by the two calculation methods are in good agreement, indicating that this method can effectively consider the interaction between the two wind turbines and the coupling effect with the platform and mooring system. Moreover, this method has higher calculation efficiency, which is more than 800 times that of the CFD method.

[0103] Verification Example 2, such as Figures 5-7As shown, the dynamic response of a parallel dual-wind turbine floating wind power system, consisting of two NREL 5MW wind turbines and an OOStar 10MW wind power platform, is presented when the control strategies of the two wind turbines differ. The results for the platform's six degrees of freedom motion and mooring tension are also given. The two wind turbines employ different control strategies: wind turbine model 1 uses a constant speed and constant pitch control strategy, while wind turbine model 2 uses a variable pitch and variable speed control strategy. As can be seen from the figure, the rotor speed and pitch angle of wind turbine model 2 change dynamically, showing a significant difference from wind turbine model 1. Although the rotor power of the two wind turbines is relatively similar, the output power differs due to the different control strategies. The tower top displacement and out-of-plane bending moment of the tower base also differ between the two wind turbines, indicating that this method can calculate the dynamic response when two wind turbines are placed on the same platform. The platform sway and pitch results are also reasonable, showing greater impact than when a single wind turbine is in operation.

[0104] In summary, this invention, based on the accurate calculation of the overall load of the parallel dual-wind turbine floating wind power equipment, improves the calculation speed by more than 800 times compared to the CFD method. It can also accurately calculate the overall dynamic response of the parallel dual-wind turbine floating wind power equipment under different control strategies. This invention lays the foundation for the large-scale promotion of parallel dual-wind turbine floating wind power equipment.

Claims

1. A parallel double wind turbine floating wind power equipment whole machine load simulation calculation method, characterized in that, Comprising: Step S1: Give the blade aerodynamic load of the floating wind turbine unit, the platform hydrodynamic load, the tower structure deformation and the blade structure deformation, and the design parameters required for system control; Step S2: Define the wind field environment, calculate the aerodynamic load of two wind turbines, and calculate the tower load vectors F1, M1 and F2, M2 at the tower base position according to the tower structure deformation; Step S3: Based on the current time roll θ1, pitch θ2 and yaw θ3 of the floating wind turbine unit platform, and the inclination angles α1 and α2 of the two wind turbines, the load transformation matrices T1 and T2 of the two wind turbines are constructed; Step S4: Transform the tower load vectors of the two wind turbines from the local coordinate system to the global coordinate system, and transfer the load action point from the tower base position to the intersection of the static water surface and the platform central axis, and add the transformed loads to obtain the total load vector F of the two wind turbines on the platform 合 , M 合 ; Step S5: According to the radiation diffraction effect of the double wind turbine floating wind power equipment platform, the platform hydrodynamic load and mooring restoring force are calculated, and the total load vector F of the wind turbine on the platform is combined 合 , M 合 The platform motion equation is established, and the displacement D, velocity V and acceleration A of the double wind turbine floating wind power equipment platform at the next time are calculated through the prediction-correction explicit time stepping method. Step S6: The displacement D, velocity V and acceleration A vectors of the floating wind turbine unit platform are transmitted to the wind turbine structure dynamics solving module, and the real-time coordinates, velocities and accelerations of the blades of the two wind turbines are calculated according to the inclination angles of the two wind turbines; Step S7: the floating type wind turbine generator platform includes a unified control system, according to the current time load, platform motion, wind speed and output power, the calculated two wind turbine tower top speed, cabin acceleration, tower load, wind wheel speed, power generation power, electromagnetic torque, input to the control system, according to the algorithm of the control system output two wind turbine blade pitch angle β1, β2 and electromagnetic torque T q1 , T q2 ; Step S8: Based on the real-time coordinates, velocities and accelerations of the blades and the blade pitch angle output by the control system, the blade aerodynamic load is repeatedly calculated, and then the structure deformation of the blade and the structure deformation of the tower are solved, until the time domain simulation calculation of the whole machine load of the floating wind turbine unit is completed.

2. The method of claim 1, wherein, In step S1, the design parameters for blade aerodynamic load calculation include chord length, twist angle and airfoil lift-drag coefficient at different radii of the blade; The design parameters required for platform hydrodynamic load calculation include platform first-order wave force, radiation damping and added mass parameters under different frequency wave action, and platform static water stiffness matrix; The design parameters required for tower structure deformation and blade structure deformation calculation include modal shape and corresponding damping ratio of each order modal of blade and tower, sectional mass, edgewise stiffness and flapwise stiffness at different radii of the blade, and sectional mass, edgewise stiffness and flapwise stiffness at different heights of the tower; The design parameters required for system control mainly include rated power, rated speed, pitch angle change gain and generator electromagnetic torque gain parameters.

3. The method of claim 1, wherein, The wind field environment in step S2 is the variation data of the three direction components of wind speed in the plane covering the wind wheel and tower of the two wind turbines with time, and the wind field is turbulent flow or steady wind; The aerodynamic load of each wind turbine is calculated respectively, and the detailed process is as follows: The blade aerodynamic force is applied to the corresponding node of the blade as a generalized active force; The generalized elastic force of the blade and the tower is calculated, considering the gravity of the blade, tower, cabin and transmission system, etc., the motion equation of the whole wind turbine is solved, the acceleration of each structure is obtained, and the load at different sections of the tower structure is calculated; Through the above process, the tower load vectors F1, M1 and F2, M2 of the two wind turbines at the tower base position in the local coordinate system are obtained respectively; each vector includes three elements, which represent the loads in x, y and z directions of the space coordinate system.

4. The method of claim 1, wherein, The load transformation matrices T1 and T2 of the two wind turbines are obtained in step S3, and the load transformation matrices are respectively: In the formula, θ1, θ2 and θ3 are the roll, pitch and yaw of the platform, respectively.

5. The method of claim 1, wherein, In step S4, the tower load vectors of the two wind turbines are transformed from the local coordinate system to the global coordinate system, and the load action points are transferred from the tower base to the intersection point of the calm water surface and the central axis of the platform. wherein and are the inverse matrices of the load transformation matrices T1 and T2, respectively, with the wind direction as the perspective, the left wind turbine being model 1 and the right wind turbine being model 2; L1 and L2 are the position vectors from the tower base of wind turbine model 1 and wind turbine model 2, respectively, to the intersection of the water surface and the platform central axis.

6. The method of claim 1, wherein, In step S5, the platform motion equation is: where t is any time instant of the floating wind turbine platform operation, m is the platform mass and the added mass matrix corresponding to the wave frequency; c is the viscous correction damping matrix; k is the platform hydrostatic stiffness matrix, h(t) is the acceleration impulse function matrix at time t, the platform radiation damping force is calculated by convolution; F 水 (t) is the hydrodynamic force on the platform, including the wave and current effects; F 系泊 (t) is the mooring restoring force; F 风电机组 (t) is the total load on the platform by the two wind turbines; the right side of the equation is a 1x6 vector, F 风电机组 (t) includes F 合 , M 合 ; Wherein, h(t) is: In the formula, ω is the working frequency, and B is the radiation damping of the platform under the wave action with the frequency ω.

7. The method of claim 5, wherein, In step S6, when the displacement D, velocity V and acceleration A vectors of the floating wind power equipment platform with double wind turbines are transmitted to the wind turbine structure dynamics solving module, the roll of the wind turbine model 1 needs to be subtracted by the inclination angle α1, and the roll of the wind turbine model 2 needs to be added by the inclination angle α2.

8. The method of claim 1, wherein, In step S8, the fourth-order Adams-Bashforth-Moulton prediction-correction time integration method is used, and the structure dynamics solving of the blades and the tower of the two wind turbines is performed once in the prediction step and the correction step.

Images