A simulation calculation method and system for a double-wind-wheel wind turbine

Abstract

This application discloses a simulation calculation method and system for a dual-rotor wind turbine. The method includes: calculating the target blade pitch angle and target generator torque of the front and rear wind turbines based on the basic parameters of the front and rear wind turbines, and generating control commands to control the simulation model of the dual-rotor wind turbine; calculating the blade aerodynamic forces and structural loads of the front and rear wind turbines in the simulation model based on the target blade pitch angle and target generator torque of the front and rear wind turbines; obtaining the blade aerodynamic torque of the front and rear wind turbines based on the blade aerodynamic forces, and calculating the current rotational speed of the front and rear wind turbines based on the blade aerodynamic torque, target generator torque, moment of inertia, and moment of inertia of the transmission system to update the basic parameters of the front and rear wind turbines; repeating the above operations iteratively to calculate the blade aerodynamic forces and structural loads of the front and rear wind turbines until the simulation time reaches a preset value, thus completing the time-domain simulation of the fully coupled dynamics of the dual-rotor wind turbine.

Description

Technical Field

[0001] This application relates to the field of wind turbine technology, and in particular to a simulation calculation method and system for a dual-rotor wind turbine. Background Technology

[0002] Tandem dual-rotor wind turbines are a new type of wind energy utilization equipment. By installing one rotor at the front and one at the rear of the nacelle, the rear rotor can further utilize the wake wind energy of the front rotor, thereby improving the wind energy utilization efficiency of the entire wind turbine and reducing the overall wind energy utilization cost, making it highly promising for application.

[0003] Significant interaction exists between the front and rear rotors of a tandem twin-rotor wind turbine. The rotation of the front rotor generates an uneven wake, affecting the aerodynamic performance of the rear rotor. Conversely, the aerodynamic forces generated by the rear rotor cause greater deformation and vibration of the tower, thus impacting the aerodynamic load on the front rotor. Therefore, the structural design of a tandem twin-rotor wind turbine must consider the interaction between the front and rear rotors.

[0004] In existing technologies, the calculation of aerodynamic loads for tandem dual-rotor wind turbines generally employs computational fluid dynamics (CFD) methods. By establishing the flow field of the tandem dual-rotor wind turbine and combining it with a turbulence model, the Navier-Stokes equations of the flow field are solved to obtain the pressure distribution on the surfaces of the front and rear rotor blades, thereby calculating the aerodynamic forces of the front and rear rotors.

[0005] The CFD method can consider the impact of the wake of the front rotor on the aerodynamic performance of the rear rotor. However, the CFD method cannot consider the blade deformation and the coordinated control of the front and rear rotors. It also ignores the blade elasticity, rotor and nacelle inertial forces, etc., and cannot accurately obtain the dynamic response of the dual-rotor wind turbine under turbulent wind conditions. In addition, the CFD method requires huge computational resources, and its computational efficiency is difficult to meet the needs of engineering applications. Summary of the Invention

[0006] The purpose of this application is to provide a simulation calculation method and system for a dual-rotor wind turbine, which considers blade deformation and the coordinated control of the front and rear rotors, and realizes the simulation calculation of the aerodynamic loads of the front and rear rotors.

[0007] To achieve the above objectives, this application provides the following technical solution:

[0008] In the first aspect, the embodiments of this application provide a simulation calculation of a dual-rotor wind turbine based on the basic parameters of the front and rear wind turbines, calculates the target blade pitch angle and the target generator torque of the front and rear wind turbines, and generates control commands to control the simulation model of the dual-rotor wind turbine.

[0009] Based on the target blade pitch angles of the front and rear wind turbines and the target generator torques of the front and rear wind turbines, the aerodynamic forces and structural loads of the front and rear wind turbines in the simulation model of the dual-wind turbine generator are calculated.

[0010] Based on the aerodynamic forces of the front and rear wind turbine blades, the aerodynamic torque of the front and rear wind turbine blades is obtained. Based on the aerodynamic torque of the front and rear wind turbine blades, the target generator torque, the moment of inertia, and the moment of inertia of the transmission system, the current rotational speed of the front and rear wind turbines is calculated and used to update the basic parameters of the front and rear wind turbines.

[0011] Repeat the above operations to iteratively calculate the blade aerodynamic forces and structural loads of the front and rear wind turbines until the simulation time reaches the preset value, thus completing the time-domain simulation of the fully coupled dynamics of the dual-rotor wind turbine.

[0012] The simulation model of the dual-rotor wind turbine includes a front rotor, a rear rotor, a nacelle, and a tower. The front rotor and the rear rotor are respectively connected to the two ends of the nacelle, and the nacelle is placed on the top of the tower. The diameter of the front rotor is larger than that of the rear rotor.

[0013] Secondly, embodiments of this application provide a simulation calculation system for a dual-rotor wind turbine, comprising:

[0014] The calculation and control unit is used to calculate the target pitch angle and target generator torque of the front and rear wind turbines based on the basic parameters of the front and rear wind turbines, and generate control commands to control the simulation model of the dual-wind turbine generator set.

[0015] The calculation unit is used to calculate the blade aerodynamic forces and structural loads of the front and rear wind turbines in the simulation model of the dual-wind turbine based on the target pitch angle and target generator torque of the front and rear wind turbines.

[0016] The parameter update unit is used to obtain the blade aerodynamic torque of the front and rear wind turbines based on the blade aerodynamic force of the front and rear wind turbines, and calculate the current speed of the front and rear wind turbines in the basic parameters of the front and rear wind turbines based on the blade aerodynamic torque of the front and rear wind turbines, the target generator torque, the moment of inertia and the moment of inertia of the transmission system, so as to update the basic parameters of the front and rear wind turbines.

[0017] The repeatable simulation unit is used to repeatedly calculate the aerodynamic forces and structural loads of the front and rear wind turbines until the simulation time reaches the set value, thus completing the time-domain simulation of the fully coupled dynamics of the dual-rotor wind turbine.

[0018] The simulation model of the dual-rotor wind turbine also includes a front rotor, a rear rotor, a nacelle, and a tower. The front rotor and the rear rotor are respectively connected to the two ends of the nacelle, and the nacelle is placed on the top of the tower. The diameter of the front rotor is larger than that of the rear rotor.

[0019] Thirdly, embodiments of this application also provide an electronic device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program or instructions to implement the steps of the aforementioned simulation calculation method for a dual-rotor wind turbine.

[0020] Fourthly, embodiments of this application also provide a computer storage medium storing a computer program or instructions, which, when executed by a processor, implement the steps of the aforementioned simulation calculation method for a dual-rotor wind turbine.

[0021] Fifthly, embodiments of this application also provide a computer program product, including a computer program or instructions, which, when executed by a processor, implement the steps of the aforementioned simulation calculation method for a dual-rotor wind turbine.

[0022] The technical effects and advantages of this application are as follows: The simulation calculation method of this application can not only consider the influence of the wake of the front wind turbine on the aerodynamic force of the rear wind turbine, but also calculate the elastic deformation of the blades and tower under the premise of considering the control effect. This application overcomes the problem that the traditional CFD method cannot consider the blade elasticity, and at the same time greatly improves the aerodynamic performance evaluation and overall dynamic response calculation efficiency of the dual-rotor wind turbine.

[0023] Other features and advantages of this application 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 application. The objectives and other advantages of this application may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart illustrating a simulation calculation method for a dual-rotor wind turbine according to an embodiment of this application;

[0026] Figure 2 This is a schematic diagram of a dual-rotor wind turbine unit according to an embodiment of this application;

[0027] Figure 3 This is a schematic diagram of the structure of a simulation calculation system for a dual-rotor wind turbine according to an embodiment of this application;

[0028] Figure 4 This is a schematic diagram of the structure of an electronic device according to an embodiment of this application;

[0029] Figure 5 This is a schematic diagram comparing the wind turbine power calculated by the method of this application and the CFD method in the embodiments of this application;

[0030] Figure 6 This is a schematic diagram comparing the wind turbine thrust calculated by the method of this application and the CFD method in the embodiments of this application;

[0031] Figure 7 This is a schematic diagram comparing the computation time of the method in this application and the CFD method in the embodiments of this application;

[0032] Figure 8 This is a schematic diagram comparing the thrust of the front and rear wind turbines under turbulent wind conditions in an embodiment of this application.

[0033] Figure 9 This is a schematic diagram comparing the power generation of the front and rear wind turbines under turbulent wind conditions in an embodiment of this application.

[0034] Figure 10 This is a schematic diagram comparing the wind speed at the hubs of the front and rear wind turbines under turbulent wind conditions in an embodiment of this application.

[0035] Figure 11 This is a schematic diagram comparing the horizontal thrust at the top of the tower for dual-rotor and single-rotor wind turbines under the same operating conditions in an embodiment of this application.

[0036] Figure 12 This is a schematic diagram comparing the vertical thrust at the top of the tower for dual-rotor and single-rotor wind turbines under the same operating conditions in this application embodiment. Detailed Implementation

[0037] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] To address the shortcomings of existing technologies, this application discloses a simulation calculation method for dual-rotor wind turbine units, such as... Figure 1 As shown, it includes the following steps:

[0039] S1: Based on the basic parameters of the front and rear wind turbines, calculate the target blade pitch angle and the target generator torque of the front and rear wind turbines, and generate control commands to control the simulation model of the dual-wind turbine generator set;

[0040] S2: Based on the target blade pitch angles of the front and rear wind turbines and the target generator torques of the front and rear wind turbines, calculate the aerodynamic forces and structural loads of the front and rear wind turbines in the simulation model of the dual-wind turbine generator set.

[0041] S3: Based on the aerodynamic forces of the front and rear wind turbine blades, obtain the aerodynamic torque of the front and rear wind turbine blades, and calculate the current rotational speed of the front and rear wind turbines in the basic parameters of the front and rear wind turbines according to the aerodynamic torque of the front and rear wind turbine blades, the target generator torque, the moment of inertia and the moment of inertia of the transmission system, so as to update the basic parameters of the front and rear wind turbines.

[0042] Step S4: Repeat steps S1 to S3 to iteratively calculate the blade aerodynamic forces and structural loads of the front and rear wind turbines until the simulation duration reaches the set value, thus completing the time-domain simulation of the fully coupled dynamics of the dual-rotor wind turbine.

[0043] Among them, such as Figure 2 As shown, the simulation model of the dual-rotor wind turbine includes a front rotor, a rear rotor, a nacelle, and a tower. The front rotor and the rear rotor are respectively connected to the two ends of the nacelle, and the nacelle is placed on the top of the tower. The diameter of the front rotor is larger than that of the rear rotor. The simulation model of the dual-rotor wind turbine also includes a transmission system, which includes an engine, a gearbox, and a rotor shaft.

[0044] In some specific embodiments, the design parameters of the dual-rotor wind turbine simulation model are set before the first calculation of the target blade pitch angle and the target generator torque of the front and rear wind turbines.

[0045] The design parameters of the simulation model of the dual-rotor wind turbine include: aerodynamic calculation parameters of the wind turbine blades and structural dynamic calculation parameters;

[0046] The aerodynamic calculation parameters of the wind turbine blades include: chord length, twist angle and airfoil lift-drag coefficient at different radii of the front and rear wind turbine blades;

[0047] The structural dynamics calculation parameters include: the mode shapes and corresponding damping ratios of each mode of the blade, the cross-sectional mass at different radii of the blade, the flapping stiffness at different radii of the blade, the swaying stiffness at different radii of the blade, the hub position coordinates and hub mass of the front and rear rotors, the rotational inertia of the transmission system, the nacelle mass, the nacelle rotational inertia, the tower mass, the distribution information of tower stiffness along the tower height, the mode shapes of the tower, and the damping ratio of the tower.

[0048] In some specific embodiments, step S1: Based on the basic parameters of the front and rear wind turbines, calculate the target blade pitch angle and the target generator torque of the front and rear wind turbines, and generate control commands to control the simulation model of the dual-rotor wind turbine, including the following steps:

[0049] The basic parameters of the front and rear wind turbines include: the current blade root load of the front and rear wind turbines, the current blade deformation of the front and rear wind turbines, the current rotational speed of the front and rear wind turbines, and the current generator torque of the front and rear wind turbines.

[0050] The basic parameters of the front and rear wind turbines are input into the simulation model control system (i.e., the control system of the simulation model of the dual wind turbine). Based on the state space of the entire dual wind turbine, the target pitch angle and target generator torque corresponding to the front and rear wind turbines are calculated by the algorithm.

[0051] The simulation model control system generates control commands based on the target pitch angle and the target generator torque to control the simulation model of the dual-rotor wind turbine.

[0052] Among them, the control closed loop of the front wind turbine needs to consider the influence factors of the rear wind turbine and the tower, and the control closed loop of the rear wind turbine needs to consider the influence factors of the front wind turbine and the tower.

[0053] The factors affecting the rear wind turbine include its rotational speed, power generation capacity, and thrust; the factors affecting the front wind turbine include its rotational speed, power generation capacity, and thrust; and the factors affecting the tower include its motion state and load.

[0054] In some specific embodiments, step S2: Based on the target pitch angle and target generator torque corresponding to the front and rear wind turbines, calculate the blade aerodynamic forces and structural loads of the front and rear wind turbines in the simulation model of the dual-wind turbine generator set, including the following steps:

[0055] Step S21: Based on the defined wind field environment data of the forewind rotor, calculate the blade aerodynamic forces and near-field wake coordinates of the forewind rotor, specifically including:

[0056] The wind field environmental data of the front wind turbine is the change data of the three directional components of the wind speed in the plane that can cover the front wind turbine and the tower over time; the type of the wind field of the front wind turbine is turbulent wind, steady-state wind, or other wind that meets the wind shear law.

[0057] (1) Based on the defined wind field environment data of the forewind rotor, the aerodynamic forces of the forewind rotor blades are calculated using the free vortex wake method and blade element momentum theory, including:

[0058] The real-time inflow velocity at each blade section of the wind turbine is obtained based on the wind turbine wind field environment data. Based on the real-time inflow velocity and the current rotational speed of the wind turbine, the induced velocity at the control point of each blade section of the wind turbine is obtained by using the free vortex wake method.

[0059] Based on the initial rotational speed of the front wind turbine and the induced speed, the velocity triangle at each blade section of the front wind turbine is determined, and the actual angle of attack of each blade section of the front wind turbine is calculated based on the velocity triangle.

[0060] Based on the airfoil lift and drag coefficients of the front wind turbine in the blade aerodynamic calculation parameters, the lift coefficient and drag coefficient at the actual angle of attack of each blade section are retrieved, and the aerodynamic forces of the corresponding blade section in the front wind turbine are calculated using the blade element momentum theory.

[0061] The aerodynamic forces of each blade section of the front wind turbine are superimposed to obtain the blade aerodynamic forces of the entire front wind turbine.

[0062] (2) Based on the defined wind field environment data of the forewind rotor, calculate the near-field wake coordinates of the forewind rotor, including:

[0063] The real-time inflow velocity at each blade section of the wind turbine is obtained based on the wind turbine wind field environment data, and the induced velocity at any wake behind the wind turbine plane is obtained by the free vortex wake method.

[0064] The induced velocity field at any wake point behind the front rotor plane is superimposed with the environmental spatial field of the real-time inflow velocity to obtain the three-dimensional velocity space coordinates of the near-field wake of the front rotor, i.e., the coordinates of the near-field wake of the front rotor are:

[0065]

[0066] In the formula, This represents the three-dimensional velocity space coordinates of the near-field wake of the front wind turbine. This represents the induced velocity at any wake point behind the front rotor plane. This value is usually negative, indicating the decrease in wind speed. This indicates the real-time inflow velocity at the cross-section of each blade of the front wind turbine.

[0067] Step S22: Considering the influence of the rear rotor, calculate the dynamic response of the front rotor blades and tower structure to obtain the displacement, velocity, and acceleration at the top of the tower; specifically including:

[0068] A multibody dynamic model of the wind turbine system is established using the Kane method; wherein, the multibody dynamic model of the wind turbine system is a multibody dynamic model of flexible bodies such as the wind turbine blades and tower, and rigid bodies such as the wind turbine hub and nacelle.

[0069] Considering the effects of gravity and motion on the structures other than the wind turbine blades, as well as the load on the rear wind turbine, the dynamic response of the front wind turbine blades and the tower structure is calculated using the multibody system dynamic model of the front wind turbine, and the displacement, velocity and acceleration of the top of the tower are obtained.

[0070] Apart from the wind turbine blades, the remaining structures include: transmission system, nacelle, wind turbine hub and tower, etc.

[0071] The load on the rear rotor is a combined effect of the rear rotor aerodynamic force, the rear rotor inertial force, and the rear rotor elastic force, excluding the effects of nacelle gravity and nacelle inertial force.

[0072] When calculating the dynamic response of the wind turbine blades and tower structure, the structural deformation of the wind turbine blades and tower is performed using the modal method, thereby accelerating the efficiency of structural dynamics solution.

[0073] Step S23: Based on the displacement, velocity, and acceleration at the top of the tower, and combined with the near-field wake coordinates of the front rotor, obtain the real-time inflow velocity of each blade section of the rear rotor under the influence of tower motion; specifically including:

[0074] Based on the displacement, velocity, and acceleration at the top of the tower, the positional relationship between the rear wind turbine hub and the top of the tower is obtained;

[0075] Based on the positional relationship between the rear wind turbine hub and the top of the tower, the spatial coordinates, velocity, and acceleration of each blade section of the rear wind turbine under the influence of tower motion are calculated.

[0076] Based on the spatial coordinates, velocity and acceleration of each blade section of the rear rotor, and the near-field wake coordinates of the front rotor, the actual inflow velocity of each blade section of the rear rotor is obtained by interpolation.

[0077] The spatial coordinates, velocity, and acceleration of each blade section of the rear wind turbine are calculated using the following formula:

[0078] Z 后 [x,y,z]=T mat Z 初始 [X,Y,X]

[0079]

[0080] In the formula, Z 后 [x,y,z] represents the spatial coordinates of any cross section of the rear rotor blade in the x, y, and z directions after considering the deformation of the top of the tower. 初始 [X,Y,X] represents the spatial coordinates of any cross-section of the rear rotor blade before deformation at the top of the tower; V 后 [x,y,z] represents the translational velocity of the rear rotor blade section in the x, y, and z directions, V 塔 [x,y,z] represents the translational velocity of the top of the tower in the x, y, and z directions, V 塔 [Rx,Ry,Rz] represents the rotational speed of the top of the tower in the x, y, and z directions; A represents the position vector between the rear rotor blade section and the top of the tower;后 [x,y,z] represents the translational acceleration of the rear rotor blade cross section in the x, y, and z directions, A 塔 [x,y,z] represents the translational acceleration of the top of the tower in the x, y, and z directions, A 塔 [Rx,Ry,Rz] represents the rotational acceleration of the top of the tower in the x, y, and z directions; T mat Let θ1, θ2, and θ3 represent the rotation angles of the tower top in the x, y, and z directions, respectively, and s be an intermediate variable with no real meaning.

[0081] Step S24: Based on the actual inflow velocity of each blade section of the rear wind turbine, the target blade pitch angle of the rear wind turbine, and the target generator torque of the rear wind turbine, calculate the aerodynamic forces of the rear wind turbine blades and solve the structural dynamic response of the wind turbine blades to obtain the load vector at the top of the rear wind turbine tower; specifically including:

[0082] Based on the actual inflow velocity of each blade section of the rear wind turbine and the target pitch angle of the rear wind turbine blades output by the simulation model control system, the aerodynamic force of the rear wind turbine blades is calculated using the generalized dynamic inflow theory or the blade element momentum theory.

[0083] Based on the aerodynamic forces of the rear wind turbine blades, the structural mechanical response of the rear wind turbine blades was calculated using the modal method.

[0084] A multibody dynamic model of the rear wind turbine system was established using the Kane method; wherein, the multibody dynamic model of the rear wind turbine system is a multibody dynamic model of the rear wind turbine hub, the rear wind turbine blades and the nacelle.

[0085] Based on the target generator torque of the rear wind turbine output by the simulation model control system, the load vector of the rear wind turbine acting on the top position of the tower is obtained by using the dynamic model of the rear wind turbine multibody system.

[0086] The rear wind turbine multibody system dynamics model is a multibody system dynamics model concerning the rear wind turbine hub, rear wind turbine blades, and nacelle.

[0087] It should be noted that before the rear rotor load calculated in step S24 is used to solve the dynamic response of the front rotor blades and tower structure in step S22 of the next round of repeated calculation, the rear rotor load needs to be reduced by the nacelle inertial force and nacelle gravity.

[0088] In some specific embodiments, during the time-domain simulation of repeatedly iterating the blade aerodynamic forces and structural loads of the front and rear wind turbines, the embodiments of this application adopt the fourth-order Adams-Bashforth-Moulton prediction-correction time integration method. The structural dynamics of the front and rear wind turbines are solved once in both the prediction step and the correction step to ensure the stability of the entire simulation time progression.

[0089] This application also provides a simulation calculation system for a dual-rotor wind turbine, such as... Figure 3 As shown, it includes:

[0090] The calculation and control unit is used to calculate the target pitch angle and target generator torque of the front and rear wind turbines based on the basic parameters of the front and rear wind turbines, and generate control commands to control the simulation model of the dual-wind turbine generator set.

[0091] The calculation unit is used to calculate the blade aerodynamic forces and structural loads of the front and rear wind turbines in the simulation model of the dual-wind turbine based on the target pitch angle and target generator torque of the front and rear wind turbines.

[0092] The parameter update unit is used to obtain the blade aerodynamic torque of the front and rear wind turbines based on the blade aerodynamic force of the front and rear wind turbines, and calculate the current speed of the front and rear wind turbines in the basic parameters of the front and rear wind turbines based on the blade aerodynamic torque of the front and rear wind turbines, the target generator torque, the moment of inertia and the moment of inertia of the transmission system, so as to update the basic parameters of the front and rear wind turbines.

[0093] The repeatable simulation unit is used to repeatedly calculate the aerodynamic forces and structural loads of the front and rear wind turbines until the simulation time reaches the set value, thus completing the time-domain simulation of the fully coupled dynamics of the dual-rotor wind turbine.

[0094] The simulation model of the dual-rotor wind turbine also includes a front rotor, a rear rotor, a nacelle, and a tower. The front rotor and the rear rotor are respectively connected to the two ends of the nacelle, and the nacelle is placed on the top of the tower. The diameter of the front rotor is larger than that of the rear rotor.

[0095] Regarding the system in the above embodiments, the specific manner in which each unit module performs operations has been described in detail in the embodiments related to the method, and will not be elaborated here.

[0096] Based on the same inventive concept, embodiments of this application also provide an electronic device, the structure of which is as follows: Figure 4 As shown, it includes a memory, a processor, and a computer program stored in the memory. The processor executes the computer program or instructions to implement the aforementioned simulation calculation method for a dual-rotor wind turbine.

[0097] Based on the same inventive concept, this application also provides a computer storage medium storing a computer program or instructions, which, when executed by a processor, implements the steps of the aforementioned simulation calculation method for a dual-rotor wind turbine.

[0098] Based on the same inventive concept, this application also provides a computer program product, including a computer program or instructions, which, when executed by a processor, implement the steps of the aforementioned simulation calculation method for a dual-rotor wind turbine.

[0099] To verify that the calculation method proposed in this application can consider the full coupling effect of a tandem dual-rotor wind turbine, a NREL 5MW wind turbine was installed on one side of the nacelle of an IEA 15MW turbine, forming a 20MW tandem dual-rotor wind turbine. Firstly, as... Figure 5 and Figure 6 The diagram compares the thrust and power of the front and rear wind turbines at different wind speeds calculated using the technical solution of this application (i.e., this method) with those calculated using traditional CFD methods, and as shown... Figure 7 The comparison of the computation time of the two methods shows that the results obtained by the two methods are in good agreement, indicating that the technical solution of this application can effectively consider the wake interference effect of the front and rear wind turbines. Moreover, the computation efficiency of this method is higher, and the time required is only 1 / 169 of that of the CFD method.

[0100] Figure 8 , Figure 9 and Figure 10 This paper presents a comparison of the calculated results for the front and rear rotors, power generation, and hub wind speed of a dual-rotor wind turbine consisting of an IEA15MW and an NREL5MW rotor under turbulent wind conditions, based on the methods described in this paper. The results show significant differences between the front and rear rotors, and the rear rotor's thrust exhibits large initial oscillations, indicating that its aerodynamic performance is influenced by the front rotor. The wind speed at the hub of the rear rotor is greater than that at the hub of the front rotor, consistent with actual wind field measurements. Furthermore, despite the higher wind speed at the hub, the wind energy utilization efficiency is lower because the wind speed is lower elsewhere on the rotor plane, consistent with real-world conditions. The calculation results are highly reasonable.

[0101] Figure 11 and Figure 12 A comparison of the dynamic response (i.e., tower top load comparison) of a dual-rotor wind turbine (comprising an IEA15MW turbine and an NREL5MW turbine) and a single-rotor wind turbine under turbulent wind conditions is presented. It can be seen that the dual-rotor wind turbine has a greater horizontal thrust, with the increase being close to the thrust of the rear rotor of the NREL5MW turbine. The vertical load at the top of the tower is also greater, with the increase being close to the weight of the NREL5MW turbine rotor; the calculation results are highly consistent with logic.

[0102] Finally, it should be noted that the above description is only a preferred embodiment of this application and is not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A simulation calculation method for a dual-rotor wind turbine, characterized in that, include: S1: Based on the basic parameters of the front and rear wind turbines, calculate the target blade pitch angle and the target generator torque of the front and rear wind turbines, and generate control commands to control the simulation model of the dual-wind turbine generator set; S2: Based on the target blade pitch angle of the front and rear wind turbines and the target generator torque of the front and rear wind turbines, calculate the blade aerodynamic forces and structural loads of the front and rear wind turbines in the simulation model of the dual-wind turbine generator set. S3: Based on the aerodynamic forces of the front and rear wind turbine blades, obtain the aerodynamic torque of the front and rear wind turbine blades, and calculate the current rotational speed of the front and rear wind turbines in the basic parameters of the front and rear wind turbines according to the aerodynamic torque of the front and rear wind turbine blades, the target generator torque, the moment of inertia and the moment of inertia of the transmission system, so as to update the basic parameters of the front and rear wind turbines. Repeat steps S1 to S3 to iteratively calculate the blade aerodynamic forces and structural loads of the front and rear wind turbines until the simulation duration reaches the preset value, thus completing the time-domain simulation of the fully coupled dynamics of the dual-rotor wind turbine. The simulation model of the dual-rotor wind turbine includes a front rotor, a rear rotor, a nacelle, and a tower. The front rotor and the rear rotor are respectively connected to the two ends of the nacelle, and the nacelle is placed on the top of the tower. The diameter of the front rotor is larger than that of the rear rotor.

2. The simulation calculation method for a dual-rotor wind turbine according to claim 1, characterized in that, Before the first calculation of the target blade pitch angle and the target generator torque of the front and rear wind turbines, the design parameters of the simulation model of the dual-rotor wind turbine are set. The design parameters of the simulation model of the dual-rotor wind turbine include: aerodynamic calculation parameters of the wind turbine blades and structural dynamic calculation parameters; The aerodynamic calculation parameters of the wind turbine blades include: chord length, twist angle and airfoil lift-drag coefficient at different radii of the front and rear wind turbine blades; The structural dynamics calculation parameters include: the mode shapes and corresponding damping ratios of each mode of the blade, the cross-sectional mass at different radii of the blade, the flapping stiffness at different radii of the blade, the swaying stiffness at different radii of the blade, the hub position coordinates and hub mass of the front and rear rotors, the rotational inertia of the transmission system, the nacelle mass, the nacelle rotational inertia, the tower mass, the distribution information of tower stiffness along the tower height, the mode shapes of the tower, and the damping ratio of the tower.

3. The simulation calculation method for a dual-rotor wind turbine according to claim 1, characterized in that, Based on the basic parameters of the front and rear wind turbines, the target blade pitch angles and target generator torques of the front and rear wind turbines are calculated, and control commands are generated to control the simulation model of the dual-rotor wind turbine, including: The basic parameters of the front and rear wind turbines include: the current blade root load of the front and rear wind turbines, the current blade deformation of the front and rear wind turbines, the current rotational speed of the front and rear wind turbines, and the current generator torque of the front and rear wind turbines. The basic parameters of the front and rear wind turbines are input into the simulation model control system. Based on the state space of the entire dual-wind turbine generator set, the target pitch angle and target generator torque corresponding to the front and rear wind turbines are calculated by the algorithm. The simulation model control system generates control commands based on the target pitch angle and the target generator torque to control the simulation model of the dual-rotor wind turbine. Among them, the control closed loop of the front wind turbine needs to consider the influence factors of the rear wind turbine and the tower, and the control closed loop of the rear wind turbine needs to consider the influence factors of the front wind turbine and the tower. The factors affecting the rear wind turbine include its rotational speed, power generation capacity, and thrust; the factors affecting the front wind turbine include its rotational speed, power generation capacity, and thrust; and the factors affecting the tower include its motion state and load.

4. The simulation calculation method for a dual-rotor wind turbine generator according to claim 1, characterized in that, Based on the target pitch angles and target generator torques corresponding to the front and rear rotors, the aerodynamic forces and structural loads on the blades of the front and rear rotors in the simulation model of the dual-rotor wind turbine are calculated, including: Based on the defined wind field environment data of the front wind turbine, the blade aerodynamic force and the near-field wake coordinates of the front wind turbine are calculated respectively. Considering the influence of the rear rotor, the dynamic response of the front rotor blades and tower structure is calculated to obtain the displacement, velocity and acceleration of the top of the tower; Based on the displacement and velocity at the top of the tower, combined with the near-field wake coordinates of the front rotor, the real-time inflow velocity of each blade section of the rear rotor under the influence of tower motion is obtained. Based on the actual inflow velocity of each blade section of the rear wind turbine, the target blade pitch angle of the rear wind turbine, and the target generator torque of the rear wind turbine, the aerodynamic force of the rear wind turbine blades is calculated and the structural dynamic response of the rear wind turbine blades is solved to obtain the load vector at the top position of the rear wind turbine tower.

5. A simulation calculation method for a dual-rotor wind turbine generator set according to claim 3 or 4, characterized in that, Based on the defined wind field environment data of the front wind turbine, the aerodynamic forces of the front wind turbine blades and the near-field wake coordinates of the front wind turbine are calculated, including: The wind farm environment data for the front rotor is the data on the change of the three directional components of the wind speed in the plane that can cover the front rotor and the tower over time. The wind field at the front wind turbine is either turbulent or steady-state. Among them, based on the defined wind field environment data of the forewind rotor, the aerodynamic forces of the forewind rotor blades are calculated using the free vortex wake method and blade element momentum theory, including: The real-time inflow velocity at each blade section of the wind turbine is obtained based on the wind turbine wind field environment data. Based on the real-time inflow velocity and the current rotational speed of the wind turbine, the induced velocity at the control point of each blade section of the wind turbine is obtained by using the free vortex wake method. Based on the initial rotational speed of the front wind turbine and the induced speed, the velocity triangle at each blade section of the front wind turbine is determined, and the actual angle of attack of each blade section of the front wind turbine is calculated based on the velocity triangle. Based on the airfoil lift and drag coefficients of the front wind turbine, the lift coefficient and drag coefficient at the actual angle of attack of each blade section are retrieved, and the aerodynamic force of the corresponding blade section in the front wind turbine is calculated using the blade element momentum theory. The aerodynamic forces of each blade section of the front wind turbine are superimposed to obtain the blade aerodynamic forces of the entire front wind turbine.

6. The simulation calculation method for a dual-rotor wind turbine generator according to claim 5, characterized in that, Based on the defined wind field environment data of the forewind rotor, calculate the near-field wake coordinates of the forewind rotor, including: The real-time inflow velocity at each blade section of the wind turbine is obtained based on the wind turbine wind field environment data, and the induced velocity at any wake behind the wind turbine plane is obtained by the free vortex wake method. The induced velocity field at any wake point behind the front wind turbine plane is superimposed with the environmental space field of the real-time inflow velocity to obtain the three-dimensional velocity space coordinates of the front wind turbine near-field wake, that is, to obtain the coordinates of the front wind turbine near-field wake. Wherein, the near-field wake coordinates of the front wind turbine are the three-dimensional velocity space coordinates of the near-field wake of the front wind turbine; The three-dimensional velocity space coordinates of the near-field wake of the front wind turbine are: ， In the formula, This represents the three-dimensional velocity space coordinates of the near-field wake of the front wind turbine. This represents the induced velocity at any wake point behind the front rotor plane; This indicates the real-time inflow velocity at the cross-section of each blade of the front wind turbine.

7. The simulation calculation method for a dual-rotor wind turbine according to claim 3, characterized in that, Considering the influence of the rear rotor, the dynamic response of the front rotor blades and tower structure is calculated to obtain the displacement, velocity, and acceleration at the top of the tower, including: A multibody dynamic model of the wind turbine system is established using the Kane method; wherein, the multibody dynamic model of the wind turbine system is a multibody dynamic model of the wind turbine blades, wind turbine hub, tower and nacelle. Considering the effects of gravity and motion on the structures other than the wind turbine blades, as well as the load on the rear wind turbine, the dynamic response of the front wind turbine blades and the tower structure is calculated using the multibody system dynamic model of the front wind turbine, and the displacement, velocity and acceleration of the top of the tower are obtained. The structure, excluding the wind turbine blades, includes: a transmission system, a nacelle, a wind turbine hub, and a tower; the load on the rear wind turbine is a combination of the aerodynamic force, inertial force, and elastic force of the rear wind turbine, excluding the effects of the nacelle's gravity and inertial force. When calculating the dynamic response of the wind turbine blades and tower structure, the structural deformation of the wind turbine blades and tower is performed using the modal method.

8. A simulation calculation method for a dual-rotor wind turbine generator according to claim 3 or 7, characterized in that, Based on the displacement, velocity, and acceleration at the top of the tower, combined with the near-field wake coordinates of the front rotor, the actual inflow velocity of each blade section of the rear rotor under the influence of tower motion is obtained, including: Based on the displacement, velocity, and acceleration at the top of the tower, the positional relationship between the rear wind turbine hub and the top of the tower is obtained; Based on the positional relationship between the rear wind turbine hub and the top of the tower, the spatial coordinates, velocity, and acceleration of each blade section of the rear wind turbine under the influence of tower motion are calculated. Based on the spatial coordinates, velocity and acceleration of each blade section of the rear rotor, and the near-field wake coordinates of the front rotor, the actual inflow velocity of each blade section of the rear rotor is obtained by interpolation. The spatial coordinates, velocity, and acceleration of each blade section of the rear wind turbine are calculated using the following formula: ， ， ， ， ， In the formula, This represents the spatial coordinates of any cross-section of the rear rotor blade in the x, y, and z directions after considering the deformation of the top of the tower. This represents the spatial coordinates of any cross-section of the rear rotor blade before deformation at the top of the tower; This represents the translational velocity of the rear rotor blade cross section in the x, y, and z directions. This represents the translational velocity of the top of the tower in the x, y, and z directions. This indicates the rotational speed of the top of the tower in the x, y, and z directions; This represents the position vector between the rear rotor blade section and the top of the tower; This represents the translational acceleration of the rear rotor blade cross section in the x, y, and z directions. This represents the translational acceleration of the top of the tower in the x, y, and z directions. This represents the rotational acceleration of the top of the tower in the x, y, and z directions; Represents the motion transformation matrix. , and These represent the rotation angles of the top of the tower in the x, y, and z directions, respectively. It is an intermediate variable with no real meaning.

9. The simulation calculation method for a dual-rotor wind turbine according to claim 3, characterized in that, Based on the actual inflow velocity of each blade section of the rear wind turbine, the target blade pitch angle, and the target generator torque, the aerodynamic forces of the rear wind turbine blades are calculated, and the structural dynamic response of the wind turbine blades is solved to obtain the load vector at the top of the rear wind turbine tower, including: Based on the actual inflow velocity of each blade section of the rear wind turbine and the target blade pitch angle of the rear wind turbine, the aerodynamic force of the rear wind turbine blades is calculated using the generalized dynamic inflow theory or the blade element momentum theory. Based on the aerodynamic forces of the rear wind turbine blades, the structural mechanical response of the rear wind turbine blades was calculated using the modal method. A multibody dynamic model of the rear wind turbine system was established using the Kane method; wherein, the multibody dynamic model of the rear wind turbine system is a multibody dynamic model of the rear wind turbine hub, the rear wind turbine blades and the nacelle. Based on the target generator torque of the rear wind turbine and the structural mechanical response of the rear wind turbine blades, the load vector of the rear wind turbine acting on the top of the tower is calculated using the multibody system dynamic model of the rear wind turbine, that is, the load vector at the top of the rear wind turbine tower is obtained.

10. A simulation calculation system for a dual-rotor wind turbine, characterized in that, include: The calculation and control unit is used to calculate the target pitch angle and target generator torque of the front and rear wind turbines based on the basic parameters of the front and rear wind turbines, and generate control commands to control the simulation model of the dual-wind turbine generator set. The calculation unit is used to calculate the blade aerodynamic forces and structural loads of the front and rear wind turbines in the simulation model of the dual-wind turbine based on the target pitch angle and target generator torque of the front and rear wind turbines. The parameter update unit is used to obtain the blade aerodynamic torque of the front and rear wind turbines based on the blade aerodynamic force of the front and rear wind turbines, and calculate the current speed of the front and rear wind turbines in the basic parameters of the front and rear wind turbines based on the blade aerodynamic torque of the front and rear wind turbines, the target generator torque, the moment of inertia and the moment of inertia of the transmission system, so as to update the basic parameters of the front and rear wind turbines. The repeatable simulation unit is used to repeatedly calculate the aerodynamic forces and structural loads of the front and rear wind turbines until the simulation time reaches the set value, thus completing the time-domain simulation of the fully coupled dynamics of the dual-rotor wind turbine. The simulation model of the dual-rotor wind turbine also includes a front rotor, a rear rotor, a nacelle, and a tower. The front rotor and the rear rotor are respectively connected to the two ends of the nacelle, and the nacelle is placed on the top of the tower. The diameter of the front rotor is larger than that of the rear rotor.

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