Actuator force-controlled loading floating fan hybrid experimental system and method

Abstract

The present invention discloses a hybrid experimental system and method for an actuator force-controlled loading floating wind turbine, the system comprising a physical model and a force-controlled loading device; the force-controlled loading device is used to load aerodynamic loads onto the physical model; the force-controlled loading device comprises an industrial computer, wherein a numerical model of a wind wheel is provided in the industrial computer, the numerical model of the wind wheel is used to calculate the aerodynamic load of the original scale wind wheel under selected working conditions, and after scaling, the aerodynamic load is sent to the force-controlled loading device via the industrial computer. The present invention can achieve accurate simulation and application of aerodynamic loads, solving a series of problems encountered by conventional analysis methods. The present invention combines the advantages of high efficiency and convenience of numerical simulation with the intuitive and faithfulness of model testing, while having a simple structure and convenient operation, and can achieve an integrated analysis of the dynamic response of floating wind turbines under wind, wave and current loads.

Description

Technical Field

[0001] The invention belongs to the field of marine engineering and relates to an actuator force-controlled loading floating fan hybrid experimental system and method. Background Art

[0002] my country's deep-sea wind energy storage capacity is enormous and offers significant development advantages, making it a key development trend in offshore wind power. Floating wind turbines are currently the most effective equipment for developing deep-sea wind energy.

[0003] Currently, the most commonly used integrated analysis methods for floating wind turbines are scaled model testing and numerical simulation. Scaled model testing offers more accurate and comprehensive simulations, but it encounters the issue of scale conflicts between the Reynolds and Froude numbers. Furthermore, it faces challenges such as matching the aerodynamic performance of the blades before and after the scale, ensuring similar mass distribution in the physical model, and simulating the turbine control strategy. Numerical simulation methods offer the advantages of convenience and efficiency, but due to the limitations of the underlying theory, they often omit or inaccurately simulate complex load characteristics, and it also struggles to account for all influencing factors in a fully coupled system. Summary of the Invention

[0004] In response to the deficiencies in the above-mentioned background technology, the present invention provides an actuator force-controlled loading floating wind turbine hybrid experiment system and method. The system and method of the present invention solve the scale conflict and fidelity problems in scale model experiments, and can quickly and reliably perform integrated analysis of floating wind turbines.

[0005] The present invention is achieved by adopting the following technical solutions:

[0006] An actuator force-controlled loading floating wind turbine hybrid experimental system, the system comprising a physical model and a force-controlled loading device; the force-controlled loading device is used to load an aerodynamic load onto the physical model; the aerodynamic load comprises an aerodynamic force and an aerodynamic torque;

[0007] The physical model is a scaled model of a floating wind turbine, arranged in a wave flow pool; the physical model includes a tower, a buoy and a mooring system; the tower and the buoy must be manufactured taking into account material density, stiffness and mass distribution conditions to ensure the similarity and accuracy between the physical model and the entity; a mass block is provided at the top of the tower, which represents the mass of the wind rotor, nacelle and hub, and is used to consider the stiffness and damping of these three parts; the mooring system must meet the similarity of the mooring line length, mooring line stiffness, mooring line buoyancy and diameter; the mooring line length is determined by the scale ratio, the mooring line stiffness is adjusted by adding a spring at the end of the mooring line, and the mooring line diameter and buoyancy are adjusted by covering the mooring line with silicone or latex tubes;

[0008] The force-controlled loading device is used to apply a pneumatic load to the top of the physical model tower. It includes an actuator, a spring plate, a base, a reaction frame, a servo controller, an industrial computer, a tension and pressure sensor, a fixed pulley, and a traction rope. The reaction frame is fixed to the base and connected to the rear end of the actuator. The actuator's telescopic head is connected to the spring plate, converting displacement control to force control by pushing and pulling the springs. The spring plate consists of two steel plates and four springs arranged symmetrically between the two plates to ensure uniform force distribution. One end of the traction rope is connected to the spring via a lower fixed pulley, and the other end is connected to the top of the physical model tower via an upper fixed pulley. The industrial computer is used to send control instructions to the servo controller, controlling the actuator to apply the pneumatic load to the top of the physical model tower. The tension and pressure sensor is used to measure the magnitude of the force applied to the tower top. The actuator should be selected based on the frequency and amplitude of the loading force after scaling. The industrial computer can adjust parameters, transmit signals and display the time history curve of force loading in real time.

[0009] In the above technical solution, further, a wind rotor numerical model is provided in the industrial control computer, and the wind rotor numerical model is used to calculate the aerodynamic load of the original scale wind rotor under the selected working condition, and is sent to the force control loading device via the industrial control computer after scaling; the method for calculating the aerodynamic load of the wind rotor numerical model is as follows: first, a wind field is generated with the help of TurbSim, and the wind speed at each point in the wind field is mapped to each blade element. According to the modified blade element momentum theory, the aerodynamic force and aerodynamic torque on the blade element are obtained, and the spanwise sum of a single blade and the superposition of all blades are obtained to obtain the aerodynamic force and aerodynamic torque acting on the wind rotor in the current time step, thereby obtaining the blade motion response; then, considering the control strategy of the wind turbine and the motion response fed back by the physical model, the blade position and attitude are updated to obtain the aerodynamic load of the next time step; and then the solution is continued cyclically to obtain the aerodynamic load of the original scale wind rotor;

[0010] According to the modified blade element momentum theory, the aerodynamic force and aerodynamic moment on the blade element are obtained, and the spanwise sum of a single blade and the superposition of all blades are used to obtain the aerodynamic force and aerodynamic moment acting on the wind rotor at the current time step. The specific method is as follows: the blade element momentum theory is used to decompose the blade into multiple blade elements along the length direction, and the aerodynamic load of the blade and the entire wind rotor is solved by the lift and drag acting on each blade element. The Prandtle tip loss model, hub loss model and Glauert model are introduced to correct the aerodynamic force and aerodynamic moment acting on the wind rotor at the current time step.

[0011] The control strategy of the wind turbine is variable speed control and variable pitch control. Before the rotor speed reaches the rated power, variable speed control is used to maintain the optimal tip speed ratio and complete the transition; after reaching the rated power, the PI algorithm is used for variable pitch control to adjust the pitch angle to maintain the rated power of the wind turbine.

[0012] With the help of TurbSim, a wind field is generated, and the wind speed at each point in the wind field is mapped to each blade element. The specific method is as follows: the Turbsim program is called to generate a three-dimensional dynamic wind field, and a steady-state wind field or a turbulent wind field can be generated according to needs; given the inflow wind speed and wind spectrum parameters, the three-directional wind speed time series that meet the statistical characteristics in the wind rotor plane can be obtained, and the wind speed parameters at all blade element positions at each time step are obtained by linear interpolation.

[0013] The present invention also provides a floating wind turbine hybrid test method with actuator force-controlled loading, the method comprising the following steps:

[0014] 1) The wind wheel numerical model in the industrial computer calculates the initial aerodynamic force and aerodynamic torque based on the wind field parameters under the selected working conditions;

[0015] 2) The wave-generating system in the wave flow tank generates waves under the selected working conditions based on the wave spectrum parameters, which act on the physical model. At the same time, the industrial computer sends control instructions to the servo controller, which controls the actuator to load the aerodynamic force onto the top of the tower of the physical model.

[0016] 3) The tower generates a motion response under the action of wind, waves and currents, and the tower motion response information is measured by the acceleration sensor. After filtering and amplification, it is transmitted to the wind rotor numerical model in the industrial computer;

[0017] 4) The rotor numerical model combines the tower motion response, blade motion response, and wind turbine control strategy to update the blade position, thereby correcting the calculated aerodynamic load and using it as the aerodynamic force and aerodynamic torque for the next time step. The force-controlled loading device applies the aerodynamic load to the top of the physical model tower in real time.

[0018] 5) Repeat steps 2)-4) to achieve integrated analysis of the floating wind turbine.

[0019] During the test, the aerodynamic load calculated by the wind rotor numerical model is loaded into the top of the physical model tower in real time through a force-controlled loading device. At the same time, the motion and displacement data of the physical model under wave and wind rotor loads are measured and fed back to the wind rotor numerical model in real time, realizing a real-time interactive closed loop of physical-numerical model information in the test, and then the mixed test cycle is carried out.

[0020] The beneficial effects of the present invention are:

[0021] (1) The present invention effectively solves the problem of the conflict between the Froude number and the Reynolds number scales.

[0022] (2) A numerical model of the wind wheel is established, which does not require consideration of blade performance scaling issues and allows for flexible addition and change of control strategies.

[0023] (3) Wind field simulation is more convenient and the obtained wind load is more accurate.

[0024] (4) Combining the advantages of high efficiency and convenience of numerical simulation and intuitive and reliable model testing, while having a simple structure and convenient operation, it can realize the integrated analysis of the dynamic response of floating wind turbines under wind, wave and current loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the method of the present invention.

[0026] Figure 2 It is a structural schematic diagram of the present invention.

[0027] In the figure: 1 is a wave pool, 2 is a physical model, 3 is an acceleration sensor, 4 is a tension and pressure sensor, 5 is a fixed pulley, 6 is a traction rope, 7 is a base, 8 is a spring plate, 9 is an actuator, 10 is a reaction frame, 11 is a data transmission line, and 12 is an industrial computer. DETAILED DESCRIPTION

[0028] The specific implementation of this system consists of two parts: preliminary test preparation and formal testing. The formal testing is conducted in a wave tank with an appropriate operating water depth. If the operating water depth is less than the required depth, the mooring system uses a cut-off water depth equivalent to provide static restoring and damping forces consistent with the full water depth.

[0029] The preliminary test preparation mainly includes the production of physical model 2, equipment assembly and determination of environmental load parameters. The specific methods are as follows:

[0030] 1. Production of physical model.

[0031] The physical model 2 is a scaled model of a floating wind turbine, including a tower, a buoy and a mooring system. The Froude similarity criterion was used in the test of the physical model 2, and the geometric similarity ratio was taken as λL. The other parameters are compared in Table 1. The physical model 2 was made according to Table 1 to ensure the consistency of the geometric dimensions and mass properties before and after the scaling. The material density, stiffness and mass distribution conditions should be comprehensively considered during the processing and manufacturing of the tower and the buoy to ensure the similarity and accuracy between the physical model and the entity. A mass block is set at the top of the tower to represent the mass of the wind rotor, nacelle and hub, which is used to consider the stiffness and damping of these three parts. The mooring system must meet the similarity of the mooring line length, mooring line stiffness, mooring line buoyancy and diameter. The mooring line length is directly determined by the scale ratio. The axial stiffness can be adjusted by adding a spring at the end of the mooring line. The mooring line diameter and buoyancy can be adjusted by covering the mooring line with silicone or latex tube.

[0032] Table 1 Hybrid experiment scaling relationship table

[0033]

[0034]

[0035] 2. Equipment assembly.

[0036] The acceleration sensor 3 is installed at the top of the tower of the physical model 2 to obtain the motion information of the physical model 2 under the action of wave and wind loads. This information is used for real-time interaction between the physical and numerical models.

[0037] according to Figure 2 Assemble the force-controlled loading device. Bolt the reaction frame 10 to the base 7. Place the actuator 9 on the base 7, close to the reaction frame 10. The telescopic head of the actuator 9 is connected to the spring plate 8. Push-pull springs convert displacement control to force control. The spring plate 8 consists of two steel plates and four springs positioned symmetrically between the two plates to ensure uniform force distribution. The spring plate 8 is connected to the top of the tower via a traction rope 6 and a fixed pulley 5. Connect the tension and pressure sensor 4 to the middle of the traction rope 6 near the top of the tower. To ensure directional stability in loading, ensure that the traction rope connecting the upper fixed pulley to the tower and the traction rope connecting the lower fixed pulley to the actuator 9 are parallel. The acceleration sensor 3, tension and pressure sensor 4, and actuator 9 are connected to an industrial computer 12 via a data transmission line 11. The industrial computer is used to send control commands to the servo controller, controlling the actuator 9 to apply the aerodynamic load to the top of the tower of the physical model 2.

[0038] 3. Determine the environmental load during the test.

[0039] The wind farm operating parameters are determined in the wind rotor numerical model, and the scaled wave spectrum parameters are determined in the wave tank for wave simulation.

[0040] The formal test part is a mixed test step method, as follows:

[0041] 1) The wind wheel numerical model in the industrial control computer 12 calculates the initial aerodynamic force and aerodynamic torque according to the wind field parameters under the selected working conditions;

[0042] 2) The wave-generating system in the wave flow pool 1 generates waves under the selected working conditions according to the wave spectrum parameters, and acts on the physical model; at the same time, the industrial computer 12 sends control instructions to the servo controller, controlling the actuator 9 to apply aerodynamic force to the top of the tower of the physical model;

[0043] 3) The tower generates a motion response under the action of wind, waves and currents, and the tower motion response information is measured by the acceleration sensor 3. After filtering and amplification, it is transmitted to the wind rotor numerical model in the industrial computer 12;

[0044] 4) The rotor numerical model combines the tower motion response, blade motion response, and wind turbine control strategy to update the blade position, thereby correcting the calculated aerodynamic load and using it as the aerodynamic force and aerodynamic torque for the next time step. The force-controlled loading device applies the aerodynamic load to the top of the physical model tower in real time.

[0045] 5) Repeat steps 2)-4) to achieve integrated analysis of the floating wind turbine.

Claims

1. An actuator force-controlled loading floating wind turbine hybrid experimental system, characterized in that: The system includes a physical model and a force-controlled loading device; the force-controlled loading device is used to load a pneumatic load onto the physical model; the pneumatic load includes aerodynamic force and aerodynamic torque; The physical model is a scaled model of a floating wind turbine, arranged in a wave flow pool; the physical model includes a tower, a buoy and a mooring system; the tower and the buoy must be manufactured taking into account material density, stiffness and mass distribution conditions to ensure the similarity and accuracy between the physical model and the entity; a mass block is provided at the top of the tower, which represents the mass of the wind rotor, nacelle and hub, and is used to consider the stiffness and damping of these three parts; the mooring system must meet the similarity of the mooring line length, mooring line stiffness, mooring line buoyancy and diameter; the mooring line length is determined by the scale ratio, the mooring line stiffness is adjusted by adding a spring at the end of the mooring line, and the mooring line diameter and buoyancy are adjusted by covering the mooring line with silicone or latex tubes; The force-controlled loading device is used to load the pneumatic load onto the top of the physical model tower; the force-controlled loading device includes an actuator, a spring plate, a base, a reaction frame, a servo controller, an industrial computer, a tension and pressure sensor, a fixed pulley and a traction rope; the reaction frame is fixed on the base and connected to the tail of the actuator; the telescopic head of the actuator is connected to the spring plate, and the displacement control is converted into force control by pushing and pulling the spring; the spring plate includes two steel plates and four springs arranged between the two steel plates, and the four springs are symmetrically arranged relative to the two steel plates to ensure that they are uniformly stressed; one end of the traction rope is connected to the spring through the lower fixed pulley, and the other end is connected to the top of the tower of the physical model through the upper fixed pulley; the industrial computer is used to send control instructions to the servo controller to control the actuator to load the pneumatic load onto the top of the tower of the physical model; the tension and pressure sensor is used to measure the magnitude of the force loaded on the top of the tower.

2. The actuator force-controlled loading floating wind turbine hybrid experimental system according to claim 1 is characterized in that: The industrial computer is provided with a wind rotor numerical model, which is used to calculate the aerodynamic load of the original-scale wind rotor under the selected working conditions, and after scaling, is sent to the force-controlled loading device via the industrial computer. The method for calculating the aerodynamic load of the wind rotor numerical model is as follows: first, a wind field is generated with the help of TurbSim, and the wind speed at each point in the wind field is mapped to each blade element. According to the modified blade element momentum theory, the aerodynamic force and aerodynamic torque on the blade element are obtained, and the spanwise sum of a single blade and the superposition of all blades are performed to obtain the aerodynamic force and aerodynamic torque acting on the wind rotor in the current time step, thereby obtaining the blade motion response; then, considering the control strategy of the wind turbine and the motion response fed back by the physical model, the blade position and attitude are updated to obtain the aerodynamic load of the next time step; and then, the solution is continued in a loop to obtain the aerodynamic load of the original-scale wind rotor; According to the modified blade element momentum theory, the aerodynamic force and aerodynamic moment on the blade element are obtained, and the spanwise sum of a single blade and the superposition of all blades are used to obtain the aerodynamic force and aerodynamic moment acting on the wind rotor at the current time step. The specific method is as follows: the blade element momentum theory is used to decompose the blade into multiple blade elements along the length direction, and the aerodynamic load of the blade and the entire wind rotor is solved by the lift and drag acting on each blade element. The Prandtle tip loss model, hub loss model and Glauert model are introduced to correct the aerodynamic force and aerodynamic moment acting on the wind rotor at the current time step. The control strategy of the wind turbine is variable speed control and variable pitch control. Before the rotor speed reaches the rated power, variable speed control is used to maintain the optimal tip speed ratio and complete the transition; after reaching the rated power, the PI algorithm is used for variable pitch control to adjust the pitch angle to maintain the rated power of the wind turbine.

3. A hybrid experimental method for actuator force-controlled loading of floating wind turbines, characterized in that: The method is implemented based on the experimental system according to claim 1 or 2, and comprises the following steps: 1) The wind wheel numerical model in the industrial computer calculates the initial aerodynamic force and aerodynamic torque based on the wind field parameters under the selected working conditions; 2) The wave-generating system in the wave flow tank generates waves under the selected working conditions based on the wave spectrum parameters, which act on the physical model. At the same time, the industrial computer sends control instructions to the servo controller, which controls the actuator to load the aerodynamic force onto the top of the tower of the physical model. 3) The tower generates a motion response under the action of wind, waves and currents, and the tower motion response information is measured by the acceleration sensor. After filtering and amplification, it is transmitted to the wind rotor numerical model in the industrial computer; 4) The rotor numerical model combines the tower motion response, blade motion response, and wind turbine control strategy to update the blade position, thereby correcting the calculated aerodynamic load and using it as the aerodynamic force and aerodynamic torque for the next time step. The force-controlled loading device applies the aerodynamic load to the top of the physical model tower in real time. 5) Repeat steps 2)-4) to achieve integrated analysis of the floating wind turbine.

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