Wind turbine generator blade trailing edge flap active control method coupled with dynamic stall model

Abstract

According to the wind turbine generator blade trailing edge flap active control method coupled with the dynamic stall model, static lift-drag coefficient curves corresponding to different trailing edge flap swing angles of different pitch angles of an airfoil profile are obtained through CFD numerical simulation analysis, and a database is established; then, the dynamic lift-drag coefficient predicted by the B-L dynamic stall model is adopted to simulate and compute the unit power, and the unit power meets the design requirement through active control over the swing angle of the wing flap at the tail edge of the blade of the airfoil, so that the problems that in the prior art, effective precision and timely response cannot be guaranteed, and the control timeliness is poor are solved; and the control hysteresis is avoided.

Description

Technical Field

[0001] The present invention is an active control method for a trailing edge flap of a wind turbine blade coupled with a dynamic stall model, and specifically relates to a method for realizing active control through a dynamic stall model coupled with an engineering model and a control module, and belongs to the technical field of wind turbine blade simulation control. Background Art

[0002] With the rapid development of the wind power industry, especially the rise of offshore wind power, wind turbines have formed a large-scale development trend. The increase in the size of wind turbines, on the one hand, enhances the flexibility of the blades, making the load more complex and variable; on the other hand, the uneven distribution of the flow field on the impeller plane is more significant, and the traditional synchronous variable pitch control strategy can no longer effectively cope with local load fluctuations. Especially in the field of offshore wind turbines, wind turbines not only need to have stronger fatigue resistance, but also require higher limit load bearing capacity, extend service life, and reduce maintenance costs. In addition, due to the diversity of unit operating conditions and real-time dynamic adjustment of control instructions, dynamic stall will occur when the inflow conditions change drastically. This dynamic change has a significant impact on the airflow on the blade surface. The high-frequency alternating loads generated by flow separation will significantly affect the fatigue life of the blades, and the extremely low lift-to-drag ratio of the stall airfoil will greatly reduce the power generation performance of the unit. At this time, the aerodynamic characteristics of the airfoil will have obvious deviations compared with the steady-state data. If the static lift-drag coefficient is continued to be used for numerical simulation, the actual aerodynamic load under unsteady flow conditions cannot be fully reflected. Therefore, there is an urgent need for a control technology that can effectively reduce the load of large wind turbines, which will help improve their safety and reliability, reduce maintenance costs, extend equipment life, and thus reduce the cost of electricity during operation.

[0003] Traditional PID control is mostly feedback control, which has a long dynamic adjustment time and a certain hysteresis, which will cause the output power of the wind turbine to fluctuate and cause the loss of power generation of the unit. In the prior art, various numerical simulations are used to control the flaps to control the overload of the unit, but the real changes of the flow field after the control are ignored, and the flaps are still controlled by static data. Although the control of the flaps has been improved, it cannot guarantee effective accuracy and timely response, and the control timeliness is poor.

[0004] For example: the invention patent with publication number CN117634046B (authorization date May 28, 2024) discloses a blade pitch and flap coordinated control load reduction method based on CFD numerical simulation. The method described in the invention includes the following steps: 1) determination of pitch angle, trailing edge length and deflection angle of the trailing edge flap; 2) geometric modeling of the two-dimensional airfoil of the blade; 3) grid division of the calculation domain; 4) setting of boundary conditions and calculation methods; 5) selection of load reduction performance analysis parameters; 6) evaluation of load reduction effect of coordinated control of pitch and trailing edge flap. The invention overcomes the problems of slow response speed and weakened control effect of wind turbines under actual working conditions, significantly improves the load reduction performance of wind turbine blades, and proposes an optimized control scheme for the changing trend of blade airfoil load under the coordinated control of pitch and trailing edge flaps, which provides a basis for further design and research on wind turbine blade load reduction under the coordinated control of pitch and trailing edge flaps. However, this invention ignores the dynamic changes of the flow field after the control is applied, and still uses static data for flap control, which cannot achieve optimal control; in addition, this invention is based on CFD numerical simulation. Although CFD is a high-precision numerical simulation method, its precise results require a large amount of computing resources, and the time required for its simulation calculation is much longer than the response time of the control module. Therefore, using CFD alone cannot directly couple and iterate with the control module, that is, it cannot apply timely and effective dynamic control.

[0005] In summary, the prior art has not yet provided a technical solution to the above and related problems. Summary of the invention

[0006] The purpose of the present invention is to provide a method for actively controlling the trailing edge flap of a wind turbine blade coupled with a dynamic stall model, by adopting CFD numerical simulation to obtain a database of static lift-drag coefficient curves at different trailing edge flap swing angles, coupling the BL dynamic stall model in actual operation to obtain the corresponding dynamic lift-drag coefficient, and simulating the computer unit power according to the lift-drag coefficient predicted by the dynamic stall model, and then actively controlling the trailing edge flap of the blade based on the difference between the unit power and the design power. The Leishman-Beddoes engineering model is coupled with a control module by utilizing the high calculation efficiency and good prediction accuracy of the Leishman-Beddoes engineering model, and a flap control method with a dynamic prediction function is designed by using the static lift-drag curve database corresponding to the different trailing edge flap swing angles of the airfoil and the BL dynamic stall model coupled thereto, so as to realize the rapid, timely and effective control of the deformation of the trailing edge flap of the blade under the dynamic working condition of the unit, thereby effectively reducing or avoiding the hysteresis of the control, being more consistent with the actual operating conditions, being able to effectively improve the control accuracy, and solving the problems that the prior art cannot guarantee effective accuracy and timely response and the control timeliness is poor.

[0007] The present invention is achieved through the following technical solutions:

[0008] A method for actively controlling a trailing edge flap of a wind turbine blade coupled with a dynamic stall model comprises the following steps:

[0009] S1. Obtaining geometric parameters and kinematic parameters of the airfoil by a given airfoil;

[0010] S2. According to the geometric parameters and kinematic parameters, static data corresponding to different trailing edge flap swing angles of the airfoil are obtained by changing the swing angle of the blade trailing edge flap when the airfoil is at different pitch angles;

[0011] S3. Analyze and calculate the static data using a CFD numerical simulation method, and establish a database of static lift-drag coefficient curves corresponding to different trailing edge flap swing angles of the wing at different pitch angles;

[0012] S4. Based on the database, a coupled BL dynamic stall model is used to predict the dynamic lift and drag coefficient of the airfoil in actual operation and simulate and calculate the corresponding unit power;

[0013] S5. Based on the difference between the unit power and the design power, the blade trailing edge flaps are actively controlled to make the unit power meet the design requirements.

[0014] Furthermore, the geometric parameters include the chord length c and the distance x from the separation point to the leading edge, and the kinematic parameters include the pitch angle α(t) and the buoyancy displacement h(t) of the airfoil.

[0015] Further, the static data is analyzed and calculated using a CFD numerical simulation method to obtain a static lift-drag coefficient curve corresponding to the airfoil and a database of static lift-drag coefficient curves corresponding to the airfoil at different trailing edge flap swing angles is established, including the following steps:

[0016] S101. Determine a calculation area through static data corresponding to different trailing edge flap swing angles of the airfoil at different pitch angles, and generate a structured grid;

[0017] S102. Analyze the corresponding relationship between the static lift and drag of the airfoil at different trailing edge flap swing angles at different pitch angles and the angle of attack α using the CFD data simulation method and generate a static lift and drag coefficient curve;

[0018] S103. Establishing a database of static lift-drag coefficient curves corresponding to different trailing edge flap swinging angles of the wing shape at different pitch angles according to the static lift-drag coefficient curves.

[0019] Furthermore, the dynamic lift-drag coefficient of the airfoil in actual operation is predicted using a coupled BL dynamic stall model, including the following steps:

[0020] S201. Use Kirchhoff model to simulate and analyze the nonlinear aerodynamic characteristics of the airfoil caused by the trailing edge separation of the wind turbine and calculate the dynamic separation point f”;

[0021] S202. Calculate the normal and tangential aerodynamic coefficients of the separation flow according to the dynamic separation point f” and

[0022] S203. Aerodynamic coefficients in the normal and tangential directions of the separated flow and The total unsteady dynamic normal force coefficient, tangential force coefficient, moment coefficient, lift coefficient and drag coefficient of the airfoil when dynamic stall occurs are calculated.

[0023] Furthermore, the aerodynamic coefficients in the normal and tangential directions of the separation flow are calculated by the following formulas: and

[0024]

[0025] In the formula, is the normal force coefficient of the separated flow, is the tangential force coefficient of the separation flow, is the total normal force coefficient under attached flow, is the total tangential force coefficient under attached flow, f″ N is the normal dynamic separation point, f″ T It is the tangential dynamic separation point.

[0026] Furthermore, the dynamic separation point f" is obtained by reversely calculating the unsteady wake dynamic separation point f', where the calculation formula of f' is as follows:

[0027]

[0028] Where ds is the differential from the leading edge to the trailing edge of the blade, T f is the separation constant.

[0029] Furthermore, the total unsteady dynamic normal force coefficient, tangential force coefficient, moment coefficient, lift coefficient and drag coefficient are calculated by the following formulas:

[0030]

[0031] In the formula, is the unsteady dynamic normal force coefficient, is the unsteady dynamic tangential force coefficient, is the unsteady dynamic moment coefficient, is the unsteady dynamic lift coefficient, is the unsteady dynamic resistance coefficient, is the incremental pitching moment at 1 / 4 chord length due to the rearward shift of the center of pressure, is the tangential force coefficient in the dynamic vortex, is the moment coefficient in the attached flow, is the moment coefficient in the separated flow, is the pitching moment increment at 1 / 4 chord length due to the rearward shift of the center of pressure, C D0 is the drag coefficient corresponding to zero lift angle of attack.

[0032] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0033] (1) The present invention establishes a database of static lift-drag coefficient curves of the airfoil at different trailing edge flap swing angles at different pitch angles by using CFD numerical simulation, and calculates the unit power based on the lift-drag coefficient simulation after the pitch change according to the BL dynamic stall model, and then actively controls the blade trailing edge flap according to the difference between the unit power and the design power, so that the unit power of the airfoil meets the design requirements, thereby solving the problems in the prior art that effective accuracy and timely response cannot be guaranteed and the control timeliness is poor, and avoiding the hysteresis of control.

[0034] (2) The present invention obtains the geometric parameters and kinematic parameters of the airfoil through a given airfoil, wherein the geometric parameters include the chord length c and the distance x from the separation point to the leading edge.

[0035] (4) The present invention determines the calculation area through the static data corresponding to the swing angles of the different trailing edge flaps of the airfoil at different pitch angles, generates a structured grid, and uses CFD to perform numerical simulation to analyze and obtain the corresponding relationship between the static lift and drag of the airfoil and the angle of attack α.

[0036] (5) The present invention uses the Kirchhoff model to simulate the nonlinear aerodynamic characteristics of the airfoil caused by the trailing edge separation of the wind turbine, and calculates the dynamic separation point f", thereby calculating the pollution of the separation flow and the aerodynamic coefficients of the separation flow. and Then, the total unsteady dynamic normal force coefficient, tangential force coefficient, moment coefficient, lift coefficient and drag coefficient are calculated when the airfoil experiences dynamic stall.

[0037] (6) The present invention improves the accuracy of solving the problem of the wind turbine under complex working conditions such as dynamic stall by coupling the dynamic stall model, and can more accurately predict the aerodynamic performance of the wind turbine under unsteady flow conditions.

[0038] (7) The present invention uses the BL dynamic stall model, which can take into account more flow mechanisms and rely on fewer empirical parameters, thereby achieving higher prediction accuracy. It is the most widely used theoretical model in wind turbine design.

[0039] In summary, a wind turbine blade trailing edge flap active control method coupled with a dynamic stall model is adopted to perform appropriate deformation control on the trailing edge of the airfoil, and the corresponding airfoil at different swing angles is numerically simulated using CFD software, and the static lift and drag coefficient curve of the airfoil is analyzed to clarify the influence of the angle of attack and swing on the aerodynamic characteristics of the airfoil; in addition, the lift and drag coefficient predicted by the dynamic stall model is used to simulate the computer unit power, and the blade trailing edge flap is actively controlled based on the difference between the unit power and the design power, thereby avoiding the adverse effects of the unit when the dynamic stall occurs. Compared with the traditional PID control, the control method coupled with dynamic stall prediction can avoid the hysteresis of the control module, effectively improve the control accuracy, and effectively improve the effective accuracy and timeliness of the flap control, so as to ensure the safety and reliability of the wind turbine, reduce maintenance costs, extend equipment life, and reduce the operating cost of the wind turbine. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a three-dimensional schematic diagram of the airfoil;

[0041] Figure 2 is the computational domain mesh of the airfoil;

[0042] Figure 3 The static lift-drag coefficient curve of the airfoil

[0043] Figure 4 This is the control flow chart of the airfoil. DETAILED DESCRIPTION

[0044] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0045] Embodiment 1:

[0046] like Figure 1 to Figure 2 As shown, this embodiment discloses a method for actively controlling the trailing edge flap of a wind turbine blade coupled with a dynamic stall model, comprising the following steps:

[0047] S1. Obtaining geometric parameters and kinematic parameters of the airfoil by a given airfoil;

[0048] S2. According to the geometric parameters and kinematic parameters, static data corresponding to different trailing edge flap swing angles of the airfoil are obtained by changing the swing angle of the blade trailing edge flap when the airfoil is at different pitch angles;

[0049] S3. Analyze and calculate the static data using a CFD numerical simulation method, and establish a database of static lift-drag coefficient curves corresponding to different trailing edge flap swing angles of the wing at different pitch angles;

[0050] S4. Based on the database, a coupled BL dynamic stall model is used to predict the dynamic lift and drag coefficient of the airfoil in actual operation and simulate and calculate the corresponding unit power;

[0051] S5. Based on the difference between the unit power and the design power, the trailing edge flap is actively controlled to make the unit power meet the design requirements.

[0052] In this embodiment, the trailing edge of the airfoil is designed as a swinging flap, and the deformation of the airfoil is controlled by changing the swinging angle of the trailing edge flap.

[0053] like Figure 4 As shown, the control process of this embodiment is as follows:

[0054] Step 1: Read airfoil parameters

[0055] Step 2: CFD simulation to calculate airfoil static data

[0056] Step 3: Create a static database of airfoils

[0057] Step 4: Use BL model to solve dynamic data

[0058] Step 5: Develop control strategies based on the obtained dynamic data

[0059] Step 6: Generate control instructions

[0060] In this embodiment, the geometric parameters of the airfoil include the chord length c and the distance x from the separation point to the leading edge, and the kinematic parameters include the pitch angle α(t) and the buoyancy displacement h(t) of the airfoil.

[0061] The unit power during actual operation of the same generator set is closely related to the dynamic lift-drag coefficient, and the corresponding unit power can be further deduced by accurately measuring and calculating the dynamic lift-drag coefficient. In this embodiment, the dynamic lift-drag coefficient of the airfoil is predicted by coupling the BL dynamic stall model, and the corresponding unit power is obtained by simulating and calculating the BL dynamic stall model.

[0062] C n =C l cosφ+C d sinφ

[0063] C t =C l sinφ-C dcosφ

[0064] The dynamic lift and drag coefficients are obtained by using the above formula to obtain the dynamic normal force coefficient and dynamic tangential force coefficient of the airfoil. l is the dynamic lift coefficient, C d is the dynamic resistance coefficient, is the inflow angle.

[0065]

[0066]

[0067] Get the airfoil dynamic normal force coefficient C n and dynamic tangential force coefficient C t Then, the axial induction factor a is obtained using the above formula n Tangential induction factor a t Where σ is the solidity of the wind wheel, is the inflow angle.

[0068]

[0069] Where B is the number of blades on the rotor, r is the position of the airfoil section along the blade span, and c is the chord length of the blade unit at r.

[0070] dM=4πr 3 ρV 0 ω(1-a n )α t dr

[0071] dP=ωdM

[0072] After solving the above parameters, use the above formula to integrate along the blade span to obtain the power of the unit. In the formula, M is the aerodynamic torque of the wind turbine, r is the position of the airfoil section along the blade span, ρ is the air density, V 0 The wind speed at the wind rotor, ω is the angular velocity of the wind rotor, d r is the span distance of the airfoil section along the blade, and P is the unit power.

[0073] In this embodiment, the blade trailing edge flap control process is as follows:

[0074] Step 1. Use the BL model to determine whether flow separation occurs on the blades of the current unit. If it does, the airfoil trailing edge angle needs to be changed to perform flow control.

[0075] Step 2. Combine the airfoil static lift and drag database and the solution results of the BL model to give the initial value of the trailing edge swing angle.

[0076] Step 3: Read the CFD static lift and drag database of the airfoil at the current trailing edge swing angle.

[0077] Step 4. Couple the BL dynamic stall model to determine whether the airfoil stalls and flows separate after the trailing edge angle changes.

[0078] Step 5. If the airfoil still stalls, return to step 2 and re-determine the trailing edge swing angle until the blade no longer experiences flow separation and then outputs the trailing edge swing angle.

[0079] Furthermore, the static data is analyzed and calculated using the CFD numerical simulation method to obtain the following Figure 3 The static lift-drag coefficient curve corresponding to the airfoil shown in the figure and establishing a database of static lift-drag coefficient curves corresponding to the airfoil at different trailing edge flap swing angles include the following steps:

[0080] S101. Determine a calculation area through static data corresponding to different trailing edge flap swing angles of the airfoil at different pitch angles, and generate a structured grid;

[0081] S102. Using the CFD data simulation method, analyze the corresponding relationship between the static lift and drag of the airfoil at different trailing edge flap swing angles at different pitch angles and the angle of attack α and generate a static lift and drag coefficient curve;

[0082] S103. Establishing a database of static lift-drag coefficient curves corresponding to different trailing edge flap swinging angles of the wing shape at different pitch angles according to the static lift-drag coefficient curves.

[0083] In step S101, the calculation area is determined, and then the following is generated: Figure 2 The structured grid shown in the figure is used, and CFD is used for numerical simulation to analyze the corresponding relationship between the static lift and drag of each airfoil and the angle of attack α.

[0084] In step S102, the nonlinear aerodynamic characteristics of the airfoil caused by the trailing edge separation of the wind turbine can be simulated by the Kirchhoff model, and the formula is as follows:

[0085]

[0086] Where f is the position of the separation point related to the angle of attack α, which can be expressed on the airfoil surface as f = x / c (complete separation when f = 0, complete adsorption when f = 1), where x is the distance from the separation point to the leading edge, and c is the chord length; by analyzing the static airfoil experimental data, a static critical value C can be obtained: N =C NL .

[0087] α 0 C N = 0, the angle of attack can be calculated by inversely calculating the following formula:

[0088]

[0089] Where α′ is the effective angle of attack corresponding to the reattachment of the fluid, and for the unsteady case it is the total normal force coefficient under the attachment flow Normal force coefficient C as a function of attack angle in unsteady conditions N (t) has a hysteresis effect and is related to C N (t) The leading edge pressure also has a hysteresis effect. In order to obtain the effective angle of attack at separation, it is necessary to consider the angle of attack deviation caused by the pressure response hysteresis. The following formula is used to describe the effect of the pressure response hysteresis on the normal force:

[0090]

[0091] In the formula, when C' N (t)>C NL When , the leading edge separation or the separation caused by the shock wave begins;

[0092] By inverting equations (1) and (2), we can obtain the relationship between the angle of attack and the flow separation point (in terms of f N represents the normal direction, f T represents the tangential direction). The formula is as follows:

[0093]

[0094] In order to eliminate the phenomenon of the loss of the negative sign of the separation point caused by squaring, formulas (3) and (4) are corrected as follows:

[0095]

[0096] Where:

[0097]

[0098] Furthermore, the dynamic lift-drag coefficient of the airfoil in actual operation is predicted using a coupled BL dynamic stall model, including the following steps:

[0099] S201. Use Kirchhoff model to simulate and analyze the nonlinear aerodynamic characteristics of the airfoil caused by the trailing edge separation of the wind turbine and calculate the dynamic separation point f”;

[0100] S202. Calculate the normal and tangential aerodynamic coefficients of the separation flow according to the dynamic separation point f” and

[0101] S203. Aerodynamic coefficients in the normal and tangential directions of the separated flow and The total unsteady dynamic normal force coefficient, tangential force coefficient, moment coefficient, lift coefficient and drag coefficient of the airfoil when dynamic stall occurs are calculated.

[0102] In step S201, the dynamic separation point f" is obtained by reversely calculating the unsteady wake dynamic separation point f', wherein the calculation formula of f' is as follows:

[0103]

[0104] Where ds is the differential from the leading edge to the trailing edge of the blade, T f is the separation constant.

[0105] In S202, the aerodynamic coefficients of the normal and tangential directions of the separated flow are calculated. and The formula is as follows:

[0106]

[0107] In the formula, is the normal force coefficient of the separated flow, is the tangential force coefficient of the separation flow, is the total normal force coefficient under attached flow, is the total tangential force coefficient under attached flow, f″ N is the normal dynamic separation point, f″ T It is the tangential dynamic separation point.

[0108] In step S203, the total unsteady dynamic normal force coefficient, tangential force coefficient, moment coefficient, lift coefficient and drag coefficient are calculated as follows when dynamic stall occurs:

[0109]

[0110] In the formula, is the unsteady dynamic normal force coefficient, is the unsteady dynamic tangential force coefficient, is the unsteady dynamic moment coefficient, is the unsteady dynamic lift coefficient, is the unsteady dynamic resistance coefficient, is the incremental pitching moment at 1 / 4 chord length due to the rearward shift of the center of pressure, is the tangential force coefficient in the dynamic vortex, is the moment coefficient in the attached flow, is the moment coefficient in the separated flow, is the increment of pitching moment at 1 / 4 chord length due to the rearward shift of the center of pressure, and the formula is as follows:

[0111]

[0112] Among them, CP v is the distance between the pressure center and 1 / 4 of the chord length, which can be expressed by the following empirical formula:

[0113]

[0114] In the formula, τ v is the dimensionless time parameter (τ v = 0, the dynamic stall vortex begins to separate from the upper surface of the airfoil, τ v =T vI when the vortex reaches the trailing edge of the airfoil).

[0115] Get the unsteady aerodynamic coefficients in airfoil coordinates and Then, project it to the direction perpendicular and parallel to the wind speed.

[0116] Upward, plus the drag coefficient C corresponding to zero lift angle of attack D0 , we can get the unsteady dynamic lift coefficient and drag coefficient The announcement is as follows:

[0117]

[0118] In the formula, is the unsteady dynamic normal force coefficient, is the unsteady dynamic tangential force coefficient, is the unsteady dynamic lift coefficient, is the unsteady dynamic resistance coefficient, C D0 is the drag coefficient corresponding to zero lift angle of attack

[0119] In actual operation, the control method of the present invention is used to actively control the trailing edge flap of the blade of the wind turbine generator set. The detailed control process is as follows:

[0120] Step 1: Use the BL model to determine whether flow separation occurs on the blades of the current unit. If it does, the airfoil trailing edge angle needs to be changed to perform flow control.

[0121] Step 2: Combine the airfoil static lift and drag database and the solution results of the BL model to give the initial value of the trailing edge swing angle.

[0122] Step 3: Read the airfoil CFD static lift and drag database at the current trailing edge swing angle.

[0123] Step 4: Couple the BL dynamic stall model to determine whether the airfoil experiences stall and flow separation after the trailing edge angle changes.

[0124] Step 5: If the airfoil still stalls, return to step 2 and re-determine the trailing edge swing angle until the blade no longer experiences flow separation and then outputs the trailing edge swing angle.

[0125] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for actively controlling the trailing edge flap of a wind turbine blade coupled with a dynamic stall model, characterized in that: The following steps are involved: S1. Obtaining geometric parameters and kinematic parameters of the airfoil by a given airfoil; S2. According to the geometric parameters and kinematic parameters, static data corresponding to different trailing edge flap swing angles of the airfoil are obtained by changing the swing angle of the blade trailing edge flap when the airfoil is at different pitch angles; S3. Analyze and calculate the static data using a CFD numerical simulation method, and establish a database of static lift-drag coefficient curves corresponding to different trailing edge flap swing angles of the wing at different pitch angles; S4. Based on the database, a coupled BL dynamic stall model is used to predict the dynamic lift and drag coefficient of the airfoil in actual operation and simulate and calculate the corresponding unit power; S5. Based on the difference between the unit power and the design power, the blade trailing edge flaps are actively controlled to make the unit power meet the design requirements.

2. The active control method for the trailing edge flap of a wind turbine blade coupled with a dynamic stall model according to claim 1, characterized in that: The geometric parameters include the chord length c and the distance x from the separation point to the leading edge, and the kinematic parameters include the pitch angle α(t) and the buoyancy displacement h(t) of the airfoil.

3. The active control method for the trailing edge flap of a wind turbine blade coupled with a dynamic stall model according to claim 1, characterized in that: The static data is analyzed and calculated by using a CFD numerical simulation method to obtain a static lift-drag coefficient curve corresponding to the airfoil and a database of static lift-drag coefficient curves corresponding to the airfoil at different trailing edge flap swing angles is established, comprising the following steps: S101. Determine a calculation area through static data corresponding to different trailing edge flap swing angles of the airfoil at different pitch angles, and generate a structured grid; S102. Using the CFD data simulation method, analyze the corresponding relationship between the static lift and drag of the airfoil at different trailing edge flap swing angles at different pitch angles and the angle of attack α and generate a static lift and drag coefficient curve; S103. Establishing a database of static lift-drag coefficient curves corresponding to different trailing edge flap swinging angles of the wing shape at different pitch angles according to the static lift-drag coefficient curves.

4. The active control method for the trailing edge flap of a wind turbine blade coupled with a dynamic stall model according to claim 1, characterized in that: The coupled BL dynamic stall model is used to predict the dynamic lift-drag coefficient of the airfoil in actual operation, comprising the following steps: S201. Use Kirchhoff model to simulate and analyze the nonlinear aerodynamic characteristics of the airfoil caused by the trailing edge separation of the wind turbine and calculate the dynamic separation point f”; S202. Calculate the normal and tangential aerodynamic coefficients of the separation flow based on the dynamic separation point and S203. Aerodynamic coefficients in the normal and tangential directions of the separated flow and The total unsteady dynamic normal force coefficient, tangential force coefficient, moment coefficient, lift coefficient and drag coefficient of the airfoil when dynamic stall occurs are calculated.

5. The active control method for the trailing edge flap of a wind turbine blade coupled with a dynamic stall model according to claim 4, characterized in that: The aerodynamic coefficients in the normal and tangential directions of the separated flow are calculated by the following formulas: and In the formula, is the normal force coefficient of the separated flow, is the tangential force coefficient of the separation flow, is the total normal force coefficient under attached flow, is the total tangential force coefficient under attached flow, f″ N is the normal dynamic separation point, f″ T It is the tangential dynamic separation point.

6. The active control method for the trailing edge flap of a wind turbine blade coupled with a dynamic stall model according to claim 5, characterized in that: The dynamic separation point f" is obtained by reversely calculating the unsteady wake dynamic separation point f', where the calculation formula of f' is as follows: Where ds is the differential from the leading edge to the trailing edge of the blade, T f is the separation constant.

7. The active control method for the trailing edge flap of a wind turbine blade coupled with a dynamic stall model according to claim 4, characterized in that: The total unsteady dynamic normal force coefficient, tangential force coefficient, moment coefficient, lift coefficient, and drag coefficient are calculated using the following formulas: In the formula, is the unsteady dynamic normal force coefficient, is the unsteady dynamic tangential force coefficient, is the unsteady dynamic moment coefficient, is the unsteady dynamic lift coefficient, is the unsteady dynamic resistance coefficient, is the incremental pitching moment at 1 / 4 chord length due to the rearward shift of the center of pressure, is the tangential force coefficient in the dynamic vortex, is the moment coefficient in the attached flow, is the moment coefficient in the separated flow, is the pitching moment increment at 1 / 4 chord length due to the rearward shift of the center of pressure, and CD0 is the drag coefficient corresponding to the zero lift angle of attack.

Images