Wind power ground test platform simulation method considering influence of flexible thin-walled cylinder

Abstract

The invention relates to a wind power ground test platform simulation method considering the influence of a flexible thin-walled cylinder, and the method is based on the premise that a tested wind turbine generator of a full-size wind power ground test platform is completely consistent with a shaft system and a generator of an actual wind turbine generator. According to the conclusion that the energy generated by the tested wind turbine generator and the actual wind turbine generator after the wind speed signals with the same size are input is the same, the generator torque of the tested wind turbine generator is kept consistent with the generator torque of the actual wind turbine generator based on the law of conservation of energy; the rotating speed of the tested wind turbine generator is equal to the rotating speed of the actual wind turbine generator by controlling the rotating speed of the dragging motor, so that the dynamic characteristics of the actual wind wheel are restored, and wind power ground test platform simulation is realized. Compared with the prior art, the influence of the flexible thin-walled cylinder on the tested unit is considered, and the simulation precision in the torsion direction of the full-size wind power ground test bed is high.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power ground test platform simulation, and in particular to a wind power ground test platform simulation method taking into account the influence of a flexible thin-walled tube, which is suitable for a full-size wind power ground test platform including a non-torque loading device and a flexible thin-walled tube link. Background Art

[0002] Offshore wind power is one of the main directions of global wind power development, but it faces challenges such as large-scale units, diverse grid-connected transmission methods, and complex operating conditions and grid-connected characteristics. In order to ensure the reliable operation and friendly grid connection of offshore wind power, it is urgent to build a test bench with offshore wind power grid-connected test and detection capabilities. Considering that the on-site test of offshore wind power is restricted by environmental and grid conditions, the test conditions are uncontrollable, resulting in high test costs, long cycles, and incomplete results. The full-scale wind power ground test platform can simulate actual wind field conditions, verify wind turbine performance, and test key components on land, greatly reducing the test cost and risk while shortening the test cycle, accelerating product development and market launch. First, the full-scale wind power ground test platform can provide a platform for collaborative innovation and cooperation for my country's wind power industry chain, improve the technical level of the entire wind power industry chain, and enhance my country's competitiveness in the global offshore wind power market. Secondly, having a full-scale wind power ground test platform can provide strong data support for my country in the formulation of international standards, enabling my country to actively participate in and lead the formulation of international wind power standards, enhance my country's international influence and voice in the field of wind power, and create favorable conditions for my country's offshore wind power industry to move towards international development.

[0003] There have been many cases of using motors to simulate actual wind turbines. When the simulation target is a wind turbine under dynamic wind speed, the traction motor will inevitably have to consider the difference in rotational inertia between the wind turbine and the traction motor. There are two ways to compensate for inertia. The first is to physically compensate for the rotational inertia by adding mechanical devices such as flywheels and gearboxes. The second is to use a compensation algorithm to achieve electrical compensation for the rotational inertia, which is divided into traction motor drive systems under torque control and speed control. The physical compensation approach has high investment costs and cannot flexibly adjust the configuration of the test bench's rotational inertia. Therefore, most wind power test benches currently use electrical compensation for rotational inertia. For wind turbine simulation systems under torque control, He Lijun et al. published "Wind Turbine Simulator for Aero-Elastic Coupling Simulation" in "Electric Power Engineering Technology" (2018, 37(05): 14-19), pointing out that the fundamental reason for the instability of the torque compensation algorithm based on speed differential is caused by a one-step time delay generated in the acceleration observation. Therefore, a first-order digital filter is used to reduce the deviation response compensation torque caused by time. Guo Honghao et al. published a paper titled "Simulation of Wind Turbine Dynamic and Static Characteristics Based on Load Torque Observation" in the Proceedings of the CSEE (2013, 33(27): 145-153). After conducting an in-depth analysis of the simulated moment of inertia and the filtering time constant of the digital filter, they pointed out that as the simulation multiple of the moment of inertia increases, the filtering depth of the filter also increases accordingly, but the deep low-pass filtering will reduce the accuracy of the dynamic simulation. Meng Yanfeng et al. published a paper titled "Improved Wind Turbine Dynamic Simulation Method Suitable for Ground Testing of Wind Turbine Drive Chain" in High Voltage Technology (2019, 45(12): 4021-4028). They designed an acceleration observer to avoid the derivative calculation of the velocity and suppress the speed noise. However, the introduction of the observer will make the simulation system more complicated and require a large amount of calculation. In summary, the above literature is all about conducting research on small-capacity wind power test platforms. Generally, a traction motor is used as the prime mover to simulate the aerodynamic torque from the wind wheel, and the torque is directly transmitted to the generator through the coupling and the mechanical flywheel. Due to the small capacity, the torque transmitted by the shaft system is small, and it is only a single-degree-of-freedom drag test without installing a shaft system non-torque loading device. The transmission path of the torsional torque from the drag motor to the generator is relatively simple, and the entire transmission system can be approximately regarded as rigid. Therefore, the drag motor reference signal only needs to consider the rotational inertia and flexible transmission characteristics of the simulated actual unit. The small capacity test platform transmission system structure diagram is as follows Figure 1 shown.

[0004] With the rapid development of large-scale units, the key components of wind turbines are subject to huge and extremely complex mechanical loads. In addition to the torque simulation in the torsional direction of the main shaft, it is necessary to simulate the influence of the load in the non-torsion direction. This requires adding a multi-degree-of-freedom non-torque loading device between the traction motor and the main shaft of the unit under test. In addition, since the impeller of an actual wind turbine is a free end in a suspended state, and the traction motor used to simulate the wind turbine in the full-scale wind power ground test platform is fixed by bearings and support devices, it is a non-free end. Therefore, while loading in five degrees of freedom, it is necessary to install a flexible thin-walled cylinder between the traction motor and the non-torque loading device, such as Figure 2 shown.

[0005] However, the existing research and the construction of ground test platforms have not considered the impact of flexible thin-walled cylinders on the units under test. The full-scale wind power ground test platform uses a low-speed, high-torque motor to drive the wind turbine under test. Affected by the elastic characteristics of its flexible thin-walled cylinder shaft system, the shaft system will experience a large torsional deformation, that is, the torsional angle increases. This deformation will cause a certain degree of system response lag, that is, there is a phase difference between the input and output, which will reduce the simulation accuracy of the test bench. Summary of the invention

[0006] The purpose of the present invention is to provide a wind power ground test platform simulation method taking into account the influence of flexible thin-walled tubes.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] A method for simulating a wind power ground test platform considering the influence of a flexible thin-walled tube. The method is based on the premise that the shaft system and the generator of a wind turbine set under test of a full-size wind power ground test platform are completely consistent with those of an actual wind turbine set. Based on the conclusion that the energy generated by the wind turbine set under test and the actual wind turbine set after inputting wind speed signals of the same magnitude is the same, and based on the law of conservation of energy, after keeping the generator torque of the wind turbine set under test consistent with that of the actual wind turbine set, the generator speed of the wind turbine set under test is controlled to be equal to that of the actual wind turbine set by controlling the speed of a drag motor, so as to restore the dynamic characteristics of the actual wind wheel and realize the simulation of the wind power ground test platform.

[0009] The parameters of the generator and wind turbine main shaft of the actual wind turbine set are consistent with those of the wind turbine set under test. The difference in mechanical parameters between the actual wind turbine set and the full-scale wind turbine ground test platform is the difference in rotational inertia between the actual wind wheel and the traction motor, and the difference in equivalent stiffness and damping coefficient between the actual wind turbine set shaft system and the overall shaft system of the full-scale wind turbine ground test platform.

[0010] The method comprises the following steps:

[0011] Establish the shaft system model of the torsion direction of the full-scale wind power ground test platform and the shaft system model of the actual wind turbine;

[0012] On the premise that the generator speed and torque of the wind turbine under test are consistent with those of the actual wind turbine, the reference speed signal of the traction motor of the full-scale wind turbine ground test platform is obtained by using the equivalent stiffness and damping parameters of the shaft system of the actual wind turbine and the flexible thin-walled tube of the full-scale wind turbine ground test platform.

[0013] The full-scale wind power ground test platform is controlled for simulation based on the reference speed signal.

[0014] The control process of the method is:

[0015] Get the input wind speed;

[0016] Based on the wind speed, the wind turbine aerodynamic torque is calculated using the wind turbine aerodynamic model;

[0017] Based on the aerodynamic torque of the wind turbine, the actual wind turbine rotor speed and generator speed are calculated using the shafting model and shafting parameters of the actual wind turbine.

[0018] The reference speed signal of the traction motor is calculated by using the equivalent stiffness and damping coefficients of the shaft system of the full-scale wind power ground test platform and the main shaft system of the actual wind turbine set;

[0019] The traction motor is controlled according to the reference speed signal to drive the generator of the wind turbine under test to rotate. After the generator of the wind turbine under test undergoes optimal torque control, its speed is input into the wind aerodynamic model to complete the closed-loop control of the entire simulation process.

[0020] The establishment of the shaft system model of the torsion direction of the full-scale wind power ground test platform is specifically as follows:

[0021] Based on the two-mass model, the influencing factors in the torsional direction are ignored, the influence of the five-degree-of-freedom non-torque loading device on the torsional moment is ignored, and the parallel axis principle is used to equate the two flexible transmission shaft systems of the thin-walled cylinder and the wind turbine main shaft with different stiffness into one flexible transmission shaft. The friction coefficient of the drag motor and the friction coefficient of the generator are ignored, and the shaft system model of the torsional direction of the full-scale wind power ground test platform is constructed.

[0022] The mathematical equation of the shaft system model of the torsion direction of the full-scale wind power ground test platform is expressed as:

[0023]

[0024] Where: m is the speed of the drag motor, ω g' is the generator speed of the wind turbine being tested; T m is the output torque of the traction motor, Tsm Transmit torque for the shaft system of the full-scale wind power ground test platform, T g' is the generator torque of the wind turbine being measured; J m is the moment of inertia of the drag motor, J g D is the moment of inertia of the generator of the wind turbine being measured; mtg is the equivalent damping coefficient of the overall flexible shaft system of the full-scale wind power ground test platform, K mtg It is the equivalent stiffness coefficient of the overall flexible shaft system of the full-scale wind power ground test platform.

[0025] The equivalent damping coefficient D of the overall flexible shaft system of the full-scale wind power ground test platform is mtg Calculated by the following formula:

[0026] D mtg =D mt +D wtg

[0027] Where: D wtg is the equivalent damping coefficient of the flexible main shaft of the wind turbine under test, D mt is the equivalent damping coefficient of the flexible thin-walled tube of the full-scale wind power ground test platform.

[0028] The equivalent stiffness coefficient K of the overall flexible shaft system of the full-scale wind power ground test platform is mtg Determined according to the parallel axis principle:

[0029]

[0030] Where: K wtg is the equivalent stiffness coefficient of the flexible main shaft of the wind turbine under test, K mt is the equivalent stiffness coefficient of the flexible thin-walled tube of the full-scale wind power ground test platform.

[0031] The establishment of the shaft system model of the actual wind turbine generator set is specifically as follows:

[0032] The transmission structure of the actual wind turbine is analyzed. Based on the two-mass model, the friction coefficient of the wind turbine and the friction coefficient of the generator are ignored, and the shaft system model of the actual wind turbine is constructed. Its mathematical equation is expressed as follows:

[0033]

[0034] Where: wt is the actual wind wheel speed, ω g is the actual wind turbine generator speed; T wt is the actual wind turbine aerodynamic torque, T s is the actual wind turbine shaft transmission torque, T g is the actual generator torque of the wind turbine; J wtis the moment of inertia of the wind wheel, J g is the generator moment of inertia; K wtg is the equivalent stiffness coefficient of the flexible main shaft of the actual wind turbine, D wtg is the equivalent damping coefficient of the flexible main shaft of an actual wind turbine.

[0035] The calculation process of the reference speed signal is:

[0036] After the full-scale wind power ground test platform inputs the wind speed signal v, the actual wind turbine rotor speed ω is solved according to the wind turbine aerodynamic model and the shaft system model of the actual wind turbine. wt , shaft transmission torque T s and generator speed ω g ;

[0037] The full-scale wind power ground test platform adopts a transmission system without a gearbox, and there is no speed ratio conversion link. Therefore, the shaft system of the full-scale wind power ground test platform transmits torque T sm The actual wind turbine shaft transmission torque T s Same, full-scale wind power ground test platform shaft system transmission torque T sm The actual wind turbine shaft transmission torque T s The Laplace expression of is:

[0038]

[0039] According to T sm =T s Combine the above two Laplace expressions to get the motor speed ω m As the parameter to be solved, according to the generator speed ω of the wind turbine being measured g' The actual wind turbine generator speed ω g equal, and the shaft system parameters of the actual wind turbine and the full-scale wind power ground test platform, and the actual wind turbine speed ω calculated in the actual wind turbine are substituted. wt and generator speed ω g , the obtained drag motor speed ω m As the reference speed signal ω of the drag motor mref , which is expressed as follows:

[0040]

[0041] Where: s is the Laplace operator, D mtg is the equivalent damping coefficient of the overall flexible shaft system of the full-scale wind power ground test platform, K mtg is the equivalent stiffness coefficient of the overall flexible shaft system of the full-scale wind power ground test platform, K wtg is the equivalent stiffness coefficient of the flexible main shaft of the actual wind turbine, Dwtg is the equivalent damping coefficient of the flexible main shaft of an actual wind turbine.

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

[0043] Aiming at the problem that a full-scale wind power ground test platform uses a low-speed and high-torque motor to drag a wind turbine under test, and is affected by the elastic characteristics of its flexible thin-walled tube shaft system, resulting in a response lag of the system and a reduction in the simulation accuracy of the test platform, the present invention provides a simulation method for a full-scale wind power ground test platform taking the flexible thin-walled tube link into consideration, by constructing a shaft system model of the full-scale wind power ground test platform in a torsional direction and a shaft system model of an actual wind turbine, and on the premise that the generator speed and torque of the wind turbine under test and the actual wind turbine are consistent, the shaft system equivalent stiffness and damping parameters of the actual wind turbine and the flexible thin-walled tube of the full-scale wind power ground test platform are used to derive a speed reference signal of the drag motor of the full-scale wind power ground test platform, thereby realizing the control of the drag motor of the full-scale wind power ground test platform, ensuring that the operating conditions of the wind turbine under test and the actual wind turbine are basically consistent, and improving the accuracy of the simulation degree in the torsional direction of the full-scale wind power ground test platform. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is the structural diagram of the transmission system of the existing small-capacity test platform;

[0045] Figure 2 This is the structural diagram of the transmission system of the existing full-scale wind power ground test platform;

[0046] Figure 3 It is a control structure diagram of the simulation method of the present invention;

[0047] Figure 4 This is a structural comparison diagram of an actual wind turbine and a full-scale wind power ground test platform;

[0048] Figure 5 This is a schematic diagram of the shaft system model of an actual wind power system;

[0049] Figure 6 The reference speed signal calculation flow chart of the traction motor of the present invention;

[0050] Figure 7 This is a simulation effect diagram of a traction motor in an embodiment;

[0051] Figure 8 This is a diagram showing the dynamic effect of a traction motor simulating a shaft system in one embodiment. DETAILED DESCRIPTION

[0052] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0053] The wind turbine under test on the full-scale wind power ground test platform is completely consistent with the shaft system and generator of the actual wind turbine, so the wind turbine under test and the actual wind turbine will generate the same energy after inputting the same wind speed signal. Based on the law of conservation of energy, while maintaining the generator torque T of the wind turbine under test, g' The actual wind turbine generator torque T g After the consistency, since P = ω·T, the speed of the generator of the wind turbine under test is controlled by controlling the speed of the drag motor to ω g' The actual wind turbine generator speed ω g If they are equal, the dynamic characteristics of the actual wind wheel can be restored and the simulation of the wind power ground test platform can be realized.

[0054] Specifically, this embodiment provides a method for simulating a wind power ground test platform taking into account the influence of a flexible thin-walled tube, comprising the following steps:

[0055] S1, establish the shaft system model of the torsion direction of the full-scale wind power ground test platform and the shaft system model of the actual wind turbine;

[0056] S2, based on the premise that the generator speed and torque of the wind turbine under test are consistent with those of the actual wind turbine, the reference speed signal of the traction motor of the full-scale wind turbine ground test platform is obtained by using the equivalent stiffness and damping parameters of the shaft systems of the actual wind turbine and the flexible thin-walled tube of the full-scale wind turbine ground test platform;

[0057] S3, based on the reference speed signal, controls the full-scale wind power ground test platform for simulation.

[0058] like Figure 3 As shown, the control process of this method is:

[0059] Get the input wind speed;

[0060] Based on the wind speed, the wind turbine aerodynamic torque is calculated using the wind turbine aerodynamic model;

[0061] Based on the aerodynamic torque of the wind turbine, the actual wind turbine rotor speed and generator speed are calculated using the shafting model and shafting parameters of the actual wind turbine.

[0062] The reference speed signal of the traction motor is calculated by using the equivalent stiffness and damping coefficients of the shaft system of the full-scale wind power ground test platform and the main shaft system of the actual wind turbine set;

[0063] The traction motor is controlled according to the reference speed signal to drive the generator of the wind turbine under test to rotate. After the generator of the wind turbine under test undergoes optimal torque control, its speed is input into the wind aerodynamic model to complete the closed-loop control of the entire simulation process.

[0064] The above method flow is further explained below in conjunction with the accompanying drawings and specific formulas.

[0065] 1. Establish the shaft system model of the torsion direction of the full-scale wind power ground test platform

[0066] Based on the two-mass model, the factors affecting the torsion direction are considered, the influence of the five-degree-of-freedom non-torque loading device on the torsion moment is ignored, and the parallel axis principle is used to make the thin-walled tube and the wind turbine main shaft two sections of flexible transmission shafts with different stiffness equivalent to one section of flexible transmission shaft, and the friction coefficient of the drag motor and the generator with very small values ​​are ignored. The shaft system model of the torsion direction of the full-scale wind power ground test platform is constructed, and its mathematical equation is expressed as follows:

[0067]

[0068] Where: m is the speed of the drag motor, ω g' is the generator speed of the wind turbine being tested; T m is the output torque of the traction motor, T sm Transmit torque for the shaft system of the full-scale wind power ground test platform, T g' is the generator torque of the wind turbine being measured; J m is the moment of inertia of the drag motor, J g D is the moment of inertia of the generator of the wind turbine being measured; mtg is the equivalent damping coefficient of the overall flexible shaft system of the full-scale wind power ground test platform, K mtg It is the equivalent stiffness coefficient of the overall flexible shaft system of the full-scale wind power ground test platform.

[0069] Among them, the equivalent damping coefficient D of the overall flexible shaft system of the full-scale wind power ground test platform is mtg Calculated by the following formula:

[0070] D mtg =D mt +D wtg (2)

[0071] Where: D wtg is the equivalent damping coefficient of the flexible main shaft of the wind turbine under test, D mt is the equivalent damping coefficient of the flexible thin-walled tube of the full-scale wind power ground test platform.

[0072] Equivalent stiffness coefficient K of the overall flexible shaft system of the full-scale wind power ground test platform mtgDetermined according to the parallel axis principle:

[0073]

[0074] Where: K wtg is the equivalent stiffness coefficient of the flexible main shaft of the wind turbine under test, K mt is the equivalent stiffness coefficient of the flexible thin-walled tube of the full-scale wind power ground test platform.

[0075] 2. Establish the shaft system model of the actual wind turbine

[0076] Since the full-scale wind power ground test platform can directly load test the actual wind turbine without scaling, the actual wind turbine and the wind turbine generator and wind turbine main shaft parameters are consistent. The difference in mechanical parameters between the actual wind turbine and the full-scale wind power ground test platform is the difference in the moment of inertia between the actual wind rotor and the traction motor, and the difference in the equivalent stiffness and damping coefficient between the actual wind turbine shaft system and the overall shaft system of the full-scale wind power ground test platform. The structure of the actual wind turbine and the full-scale wind power ground test platform is as follows: Figure 4 shown.

[0077] In order to obtain the reference speed signal of the traction motor, the transmission structure of the actual wind turbine is first analyzed. Based on the two-mass block model, the transmission system of the direct-drive wind turbine is taken as an example, and the wind turbine friction coefficient and generator friction coefficient with very small values ​​are ignored to construct the shaft system model of the actual wind turbine. Its mathematical equation is expressed as follows:

[0078]

[0079] Where: wt is the actual wind wheel speed, ω g is the actual wind turbine generator speed; T wt is the actual wind turbine aerodynamic torque, T s is the actual wind turbine shaft transmission torque, T g is the actual generator torque of the wind turbine; J wt is the moment of inertia of the wind wheel, J g is the generator moment of inertia; K wtg is the equivalent stiffness coefficient of the flexible main shaft of the actual wind turbine, D wtg is the equivalent damping coefficient of the flexible main shaft of the actual wind turbine. The shaft system model of the actual wind turbine is as follows: Figure 5 shown.

[0080] 3. Calculate the reference speed signal

[0081] like Figure 6 As shown, the calculation of the reference speed signal specifically includes the following steps:

[0082] After the full-scale wind power ground test platform inputs the wind speed signal v, the actual wind turbine rotor speed ω is solved according to the wind turbine aerodynamic model and the shaft system model of the actual wind turbine. wt , shaft transmission torque T s and generator speed ω g ;

[0083] The full-scale wind power ground test platform adopts a transmission system without a gearbox, and there is no speed ratio conversion link. Therefore, the shaft system of the full-scale wind power ground test platform transmits torque T sm The actual wind turbine shaft transmission torque T s The same, that is, T sm =T s .

[0084] The shaft system transmission torque T of the full-scale wind power ground test platform sm The actual wind turbine shaft transmission torque T s The Laplace expression of is:

[0085]

[0086]

[0087] According to T sm =T s Combining equations (5) and (6), we can get the motor speed ω m As the parameter to be solved, according to the generator speed ω of the wind turbine being measured g' The actual wind turbine generator speed ω g equal, and the shaft system parameters of the actual wind turbine and the full-scale wind power ground test platform, and the actual wind turbine speed ω calculated in the actual wind turbine are substituted. wt and generator speed ω g , the obtained drag motor speed ω m As the reference speed signal ω of the drag motor mref , which is expressed as follows:

[0088]

[0089] Where: s is the Laplace operator, D mtg is the equivalent damping coefficient of the overall flexible shaft system of the full-scale wind power ground test platform, K mtg is the equivalent stiffness coefficient of the overall flexible shaft system of the full-scale wind power ground test platform, K wtg is the equivalent stiffness coefficient of the flexible main shaft of the actual wind turbine, D wtg is the equivalent damping coefficient of the flexible main shaft of an actual wind turbine.

[0090] In order to verify the feasibility of the present invention and the correctness of the theoretical analysis, the Simulink simulation software is used for simulation verification. Taking a 1.5MW permanent magnet direct-drive wind turbine as the unit under test, Table 1 gives some main parameters of the simulated wind turbine and PMSG.

[0091] Table 1 Parameters of simulated wind turbine and tested wind turbine

[0092] Wind turbine parameters Numeric PMSG parameters Numeric Maximum power generation of the unit / MW 1.64 Rated power / MW 1.5 Blade radius / m 43 Rated voltage of the unit / V 690 Rated wind speed (m / s) 10 Rated speed / (rad / s) 2.709 Wind wheel moment of inertia / pu 9.846 Moment of inertia / pu 2.2 Spindle stiffness coefficient / pu 173.12 Stator resistance / Ω 0.0058 Spindle damping coefficient / pu 0.02 Rotor resistance / Ω 0.0062

[0093] Since the shaft system parameters of the flexible thin-walled tube are uncertain, it is assumed that the shaft system stiffness and damping coefficient are consistent with the actual wind turbine main shaft system, that is, K mt =K wtg =173.12, D mt =D wtg =0.02, according to formula (2) and formula (3), the equivalent stiffness and damping coefficient of the flexible shaft system of the full-scale wind power ground test platform can be calculated as K mtg =86.56, D mtg =0.04. Verification is carried out according to the measured wind speed of 7m / s. The comparison chart is as follows Figure 7 As shown. Figure 7 It can be seen that the generator speed fluctuates continuously during the wind speed change, and the shaft torque fluctuates frequently. The method of the present invention ensures that the operating conditions of the wind turbine under test and the actual wind turbine are basically consistent. Since the present invention focuses on the dynamic simulation of the shaft system, the shaft torque T of the wind turbine under test and the actual wind turbine are s An FFT analysis was performed and the results are as follows Figure 8 As shown. Figure 8 It can be seen that within 0-2HZ, the torsional vibration amplitude of the test platform and the actual wind turbine shaft system under the simulation method of the present invention is basically consistent, which verifies the accuracy of the simulation degree of the present invention in the torsional direction of the full-scale wind power ground test bench.

[0094] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning, or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A wind power ground test platform simulation method considering the influence of flexible thin-walled tubes, characterized in that: This method is based on the premise that the shaft system and generator of the wind turbine under test of the full-scale wind power ground test platform are completely consistent with those of the actual wind turbine. Based on the conclusion that the energy generated by the wind turbine under test and the actual wind turbine is the same after the wind speed signals of the same magnitude are input, and based on the law of conservation of energy, after keeping the generator torque of the wind turbine under test consistent with that of the actual wind turbine, the speed of the generator of the wind turbine under test is controlled to make the speed of the generator of the wind turbine under test equal to that of the actual wind turbine, so as to restore the dynamic characteristics of the actual wind wheel and realize the simulation of the wind power ground test platform.

2. A wind power ground test platform simulation method considering the influence of flexible thin-walled tube according to claim 1, characterized in that: The parameters of the generator and wind turbine main shaft of the actual wind turbine set are consistent with those of the wind turbine set under test. The difference in mechanical parameters between the actual wind turbine set and the full-scale wind turbine ground test platform is the difference in rotational inertia between the actual wind wheel and the traction motor, and the difference in equivalent stiffness and damping coefficient between the actual wind turbine set shaft system and the overall shaft system of the full-scale wind turbine ground test platform.

3. A wind power ground test platform simulation method considering the influence of flexible thin-walled tube according to claim 1, characterized in that: The method comprises the following steps: Establish the shaft system model of the torsion direction of the full-scale wind power ground test platform and the shaft system model of the actual wind turbine; On the premise that the generator speed and torque of the wind turbine under test are consistent with those of the actual wind turbine, the reference speed signal of the traction motor of the full-scale wind turbine ground test platform is obtained by using the equivalent stiffness and damping parameters of the shaft system of the actual wind turbine and the flexible thin-walled tube of the full-scale wind turbine ground test platform. The full-scale wind power ground test platform is controlled for simulation based on the reference speed signal.

4. A wind power ground test platform simulation method considering the influence of flexible thin-walled tube according to claim 3, characterized in that: The control process of the method is: Get the input wind speed; Based on the wind speed, the wind turbine aerodynamic torque is calculated using the wind turbine aerodynamic model; Based on the aerodynamic torque of the wind turbine, the actual wind turbine rotor speed and generator speed are calculated using the shafting model and shafting parameters of the actual wind turbine. The reference speed signal of the traction motor is calculated by using the equivalent stiffness and damping coefficients of the shaft system of the full-scale wind power ground test platform and the main shaft system of the actual wind turbine set; The traction motor is controlled according to the reference speed signal to drive the generator of the wind turbine under test to rotate. After the generator of the wind turbine under test undergoes optimal torque control, its speed is input into the wind aerodynamic model to complete the closed-loop control of the entire simulation process.

5. The method for simulating a wind power ground test platform considering the influence of a flexible thin-walled tube according to claim 3 is characterized in that: The establishment of the shaft system model of the torsion direction of the full-scale wind power ground test platform is specifically as follows: Based on the two-mass model, the influencing factors in the torsional direction are ignored, the influence of the five-degree-of-freedom non-torque loading device on the torsional moment is ignored, and the parallel axis principle is used to equate the two flexible transmission shaft systems of the thin-walled cylinder and the wind turbine main shaft with different stiffness into one flexible transmission shaft. The friction coefficient of the drag motor and the friction coefficient of the generator are ignored, and the shaft system model of the torsional direction of the full-scale wind power ground test platform is constructed.

6. A wind power ground test platform simulation method considering the influence of flexible thin-walled tube according to claim 3, characterized in that: The mathematical equation of the shaft system model of the torsion direction of the full-scale wind power ground test platform is expressed as: Where: m is the speed of the drag motor, ω g' is the generator speed of the wind turbine being tested; T m is the output torque of the traction motor, T sm Transmit torque for the shaft system of the full-scale wind power ground test platform, T g' is the generator torque of the wind turbine under test; J m is the moment of inertia of the drag motor, J g D is the moment of inertia of the generator of the wind turbine being measured; mtg is the equivalent damping coefficient of the overall flexible shaft system of the full-scale wind power ground test platform, K mtg It is the equivalent stiffness coefficient of the overall flexible shaft system of the full-scale wind power ground test platform.

7. A wind power ground test platform simulation method considering the influence of flexible thin-walled tube according to claim 6, characterized in that: The equivalent damping coefficient D of the overall flexible shaft system of the full-scale wind power ground test platform is mtg Calculated by the following formula: D mtg =D mt +D wtg Where: D wtg is the equivalent damping coefficient of the flexible main shaft of the wind turbine under test, D mt is the equivalent damping coefficient of the flexible thin-walled tube of the full-scale wind power ground test platform.

8. A method for simulating a wind power ground test platform considering the influence of a flexible thin-walled tube according to claim 6, characterized in that: The equivalent stiffness coefficient K of the overall flexible shaft system of the full-scale wind power ground test platform is mtg Determined according to the parallel axis principle: Where: K wtg is the equivalent stiffness coefficient of the flexible main shaft of the wind turbine under test, K mt is the equivalent stiffness coefficient of the flexible thin-walled tube of the full-scale wind power ground test platform.

9. The method for simulating a wind power ground test platform considering the influence of a flexible thin-walled tube according to claim 3 is characterized in that: The establishment of the shaft system model of the actual wind turbine generator set is specifically as follows: The transmission structure of the actual wind turbine is analyzed. Based on the two-mass model, the friction coefficient of the wind turbine and the friction coefficient of the generator are ignored, and the shaft system model of the actual wind turbine is constructed. Its mathematical equation is expressed as follows: Where: wt is the actual wind wheel speed, ω g is the actual wind turbine generator speed; T wt is the actual wind turbine aerodynamic torque, T s is the actual wind turbine shaft transmission torque, T g is the actual generator torque of the wind turbine; J wt is the moment of inertia of the wind wheel, J g is the generator moment of inertia; K wtg is the equivalent stiffness coefficient of the flexible main shaft of the actual wind turbine, D wtg is the equivalent damping coefficient of the flexible main shaft of an actual wind turbine.

10. A wind power ground test platform simulation method considering the influence of flexible thin-walled tube according to claim 3, characterized in that: The calculation process of the reference speed signal is: After the full-scale wind power ground test platform inputs the wind speed signal v, the actual wind turbine rotor speed ω is solved according to the wind turbine aerodynamic model and the shaft system model of the actual wind turbine. wt , shaft transmission torque T s and generator speed ω g ; The full-scale wind power ground test platform adopts a transmission system without a gearbox, and there is no speed ratio conversion link. Therefore, the shaft system of the full-scale wind power ground test platform transmits torque T sm The actual wind turbine shaft transmission torque T s Same, full-scale wind power ground test platform shaft system transmission torque T sm The actual wind turbine shaft transmission torque T s The Laplace expression of is: According to T sm =T s Combine the above two Laplace expressions to get the motor speed ω m As the parameter to be solved, according to the generator speed ω of the wind turbine being measured g' The actual wind turbine generator speed ω g equal, and the shaft system parameters of the actual wind turbine and the full-scale wind power ground test platform, and the actual wind turbine speed ω calculated in the actual wind turbine are substituted. wt and generator speed ω g , the obtained drag motor speed ω m As the reference speed signal ω of the drag motor mref , which is expressed as follows: Where: s is the Laplace operator, D mtg is the equivalent damping coefficient of the overall flexible shaft system of the full-scale wind power ground test platform, K mtg is the equivalent stiffness coefficient of the overall flexible shaft system of the full-scale wind power ground test platform, K wtg is the equivalent stiffness coefficient of the flexible main shaft of the actual wind turbine, D wtg is the equivalent damping coefficient of the flexible main shaft of an actual wind turbine.

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