Rotation speed tracking control method and system for floating wind turbine generator set operating above rated wind speed

Abstract

A rotation speed tracking control method and system for a floating wind turbine generator set operating above a rated wind speed, the method comprising: acquiring a gearbox ratio and the rated electromagnetic torque of a wind turbine generator set, the rotation speed of a rotor of the wind turbine generator set, the pitch angular velocity of a floating foundation of the wind turbine generator set, and the inflow wind speed of the wind turbine generator set; on the basis of the gearbox ratio, the rated electromagnetic torque, the rotation speed of the rotor, the pitch angular velocity of the floating foundation, and the inflow wind speed, using a first electromagnetic torque formula to calculate an electromagnetic torque control signal of the wind turbine generator set; sending to a wind turbine generator set controller the electromagnetic torque control signal, so as to eliminate a limit cycle, and controlling the electromagnetic torque of the wind turbine generator set, so as to keep the rotation speed of the rotor of the wind turbine generator set constant.

Description

Speed ​​tracking control method and system for floating wind turbine generator system above rated wind speed

[0001] This application claims priority to a Chinese patent application filed with the Patent Office of China on November 15, 2023, with application number 202311526998.4 and entitled “Speed ​​tracking control method and system for floating wind turbine generator systems above rated wind speed”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present invention relates to the technical field of wind power generation, and in particular to a rotational speed tracking control method and a rotational speed tracking control system for a floating wind turbine generator set above a rated wind speed. Background Art

[0003] Due to technical and cost limitations, current wind energy utilization primarily comes from fixed-base onshore and offshore wind turbines. However, with the development of offshore wind turbines, deep-sea areas with vast and stable wind resources have become the primary areas for future wind power development. Floating offshore wind turbines are an optimal option for harnessing wind energy. However, when operating in wind speeds above rated speed, large rotor speed fluctuations are often observed. This phenomenon severely impacts the turbine's power output, significantly increases mechanical fatigue, and can even damage the turbine.

[0004] To prevent speed oscillation in floating wind turbines above rated wind speeds, the industry's common approach is to reduce the speed controller gain. However, this strategy doesn't fundamentally solve the problem, as a controller with a small gain can't respond quickly enough to wind speed changes, resulting in speed overshoot.

[0005] Previous studies have shown that the oscillation of the wind rotor speed may be caused by limit cycles. However, research on eliminating limit cycles through control strategies to achieve effective speed tracking remains a blank.

[0006] Summary of the Invention

[0007] In view of the above problems, the present invention proposes a speed tracking control method and a speed tracking control system for a floating wind turbine generator set at wind speeds above the rated wind speed.

[0008] An embodiment of the present invention provides a method for tracking and controlling the rotational speed of a floating wind turbine generator system at wind speeds above rated wind speed. The method comprises:

[0009] Obtaining the gearbox ratio and rated electromagnetic torque of the wind turbine generator set;

[0010] Obtaining a rotor speed of the wind turbine;

[0011] Obtaining a floating foundation pitch angular velocity of the wind turbine;

[0012] Obtaining an inflow wind speed of the wind turbine generator system;

[0013] Calculating an electromagnetic torque control signal of the wind turbine generator set using a first electromagnetic torque formula based on the gearbox ratio, the rated electromagnetic torque, the rotor speed, the floating foundation pitch angular velocity, and the inflow wind speed;

[0014] Sending the electromagnetic torque control signal to the wind turbine controller to eliminate the limit cycle, control the electromagnetic torque of the wind turbine, and further control the rotor speed of the wind turbine to be constant;

[0015] Wherein, the first electromagnetic torque formula is:

[0016] In the above formula: T e is the electromagnetic torque corresponding to the electromagnetic torque control signal, C q is the aerodynamic torque coefficient, N Gear is the gearbox ratio, is the rated electromagnetic torque, Ω r is the rotor speed, v0 is the inflow wind speed, β is the pitch angle, ρ is the air density, R is the impeller radius, L T is the tower height, v rel is the relative wind speed, It is the floating basic pitch angular velocity.

[0017] Optionally, obtaining the rotor speed of the wind turbine generator system includes:

[0018] Measuring the wind wheel speed to obtain a measurement signal;

[0019] The wind wheel speed is obtained by filtering the measurement signal through a low-pass filter.

[0020] Optionally, obtaining the inflow wind speed of the wind turbine generator system includes:

[0021] Obtain the effective wind speed measurement value of the wind rotor through wind measuring equipment;

[0022] The effective wind speed measurement value is used as the inflow wind speed.

[0023] Optionally, filtering the measurement signal through a low-pass filter includes:

[0024] The measurement signal is passed through a cutoff frequency of The low-pass filter is used to filter, where is the rated wind wheel speed.

[0025] Optionally, the speed tracking control method further includes:

[0026] Calculate the aerodynamic torque compensation value;

[0027] Calculating an electromagnetic torque control signal of the wind turbine generator set using a second electromagnetic torque formula based on the aerodynamic torque compensation value and the gearbox ratio;

[0028] Among them, the second electromagnetic torque formula is:

[0029] In the above formula, T a,comp is the aerodynamic torque compensation value.

[0030] Optionally, calculating the aerodynamic torque compensation value includes:

[0031] The aerodynamic torque of the wind turbine is decomposed according to the square of the relative wind speed in its expression, and the aerodynamic torque T a Expands to: Right now:

[0032] Based on T a,cross and The respective expressions are calculated to obtain the aerodynamic torque compensation value

[0033] Alternatively, ignoring the loss, since P a =P e =N Gear Ω r T e , then substituting the first electromagnetic torque formula into the equation, we can get the following formula:

[0034] In the above formula, P a is the aerodynamic power of the wind turbine, is the rated aerodynamic power of the wind turbine, P e is the electromagnetic power;

[0035] Substituting the above formula into a model formula obtained by considering two degrees of freedom of rotor rotation and floating foundation pitch of the floating wind turbine at a wind speed above the rated speed, and using the Bendixon criterion to make a judgment, it is determined that the Bendixon discriminant function is always negative within the definition domain, that is, the limit cycle does not exist, so that the limit cycle is eliminated when the wind turbine is controlled by the electromagnetic torque control signal;

[0036] Wherein, the model formula is:

[0037] In the above two equations, J is the moment of inertia of the wind wheel, I Mass is the pitching moment of inertia of the floating foundation, M HS is the hydrostatic restoring moment, M rad is the hydrodynamic radiation torque, M diff is the hydrodynamic diffraction moment, F a It's aerodynamic thrust.

[0038] Optionally, the speed tracking control method further includes:

[0039] Obtaining a speed control signal by calculation based on the rated wind rotor speed and the wind rotor speed;

[0040] The wind wheel speed is controlled according to the speed control signal.

[0041] Optionally, the speed control signal is obtained by calculation based on the rated wind rotor speed and the wind rotor speed, including:

[0042] Calculating the difference between the rated wind rotor speed and the wind rotor speed;

[0043] The difference is used as the speed control signal.

[0044] An embodiment of the present invention provides a speed tracking and control system for a floating wind turbine generator set at wind speeds above rated speed, the speed tracking and control system comprising:

[0045] A basic parameter module, used to obtain the gearbox ratio and rated electromagnetic torque of the wind turbine;

[0046] A speed module, used to obtain the speed of the wind turbine rotor;

[0047] A pitch angular velocity module, configured to obtain a floating basic pitch angular velocity of the wind turbine;

[0048] An inflow wind speed module, used to obtain the inflow wind speed of the wind turbine;

[0049] an electromagnetic torque calculation module, configured to calculate an electromagnetic torque control signal of the wind turbine generator set using a first electromagnetic torque formula based on the gearbox ratio, the rated electromagnetic torque, the rotor speed, the floating foundation pitch angular velocity, and the inflow wind speed;

[0050] an electromagnetic torque control module, configured to send the electromagnetic torque control signal to the wind turbine controller to eliminate the limit cycle, control the electromagnetic torque of the wind turbine, and further control the rotor speed of the wind turbine to be constant;

[0051] Wherein, the first electromagnetic torque formula is:

[0052] In the above formula: T e is the electromagnetic torque corresponding to the electromagnetic torque control signal, C q is the aerodynamic torque coefficient, N Gear is the gearbox ratio, is the rated electromagnetic torque, Ω r is the rotor speed, v0 is the inflow wind speed, β is the pitch angle, ρ is the air density, R is the impeller radius, L T is the tower height, v rel is the relative wind speed, It is the floating basic pitch angular velocity.

[0053] Optionally, the rotation speed module includes:

[0054] A measuring unit, used to measure the speed of the wind wheel to obtain a measurement signal;

[0055] The filtering unit is used to filter the measurement signal through a low-pass filter to obtain the wind wheel speed.

[0056] Optionally, the inflow wind speed module is specifically used to:

[0057] Obtain the effective wind speed measurement value of the wind rotor through wind measuring equipment;

[0058] The effective wind speed measurement value is used as the inflow wind speed.

[0059] Optionally, the filtering unit is specifically configured to:

[0060] The measurement signal is passed through a cutoff frequency of The low-pass filter is used to filter, where is the rated wind wheel speed.

[0061] Optionally, the speed tracking and control system further includes:

[0062] A pneumatic torque compensation value module is used to calculate the pneumatic torque compensation value;

[0063] a torque calculation module, configured to calculate an electromagnetic torque control signal of the wind turbine generator set using a second electromagnetic torque formula based on the aerodynamic torque compensation value and the gearbox ratio;

[0064] Among them, the second electromagnetic torque formula is:

[0065] In the above formula, T a,comp is the aerodynamic torque compensation value.

[0066] Optionally, the aerodynamic torque compensation value module is specifically used to:

[0067] The aerodynamic torque of the wind turbine is decomposed according to the square of the relative wind speed in its expression, and the aerodynamic torque T a Expands to: Right now:

[0068] Based on T a,cross and The respective expressions are calculated to obtain the aerodynamic torque compensation value

[0069] When the loss is neglected, since P a =P e =N Gear Ω r T e , then substituting the first electromagnetic torque formula into the equation, we can get the following formula:

[0070] In the above formula, P a is the aerodynamic power of the wind turbine, is the rated aerodynamic power of the wind turbine, P e is the electromagnetic power;

[0071] Substituting the above formula into a model formula obtained by considering two degrees of freedom of rotor rotation and floating foundation pitch of the floating wind turbine at a wind speed above the rated speed, and using the Bendixon criterion to make a judgment, it is determined that the Bendixon discriminant function is always negative within the definition domain, that is, the limit cycle does not exist, so that the limit cycle is eliminated when the wind turbine is controlled by the electromagnetic torque control signal;

[0072] Wherein, the model formula is:

[0073] In the above two equations, J is the moment of inertia of the wind wheel, I Mass is the pitching moment of inertia of the floating foundation, M HS is the hydrostatic restoring moment, M rad is the hydrodynamic radiation torque, M diff is the hydrodynamic diffraction moment, F a It's aerodynamic thrust.

[0074] Optionally, the speed tracking and control system further includes:

[0075] A speed calculation module, configured to calculate a speed control signal based on the rated wind rotor speed and the wind rotor speed;

[0076] The speed control module is used to control the speed of the wind wheel according to the speed control signal.

[0077] Optionally, the rotation speed calculation module is specifically configured to:

[0078] Calculating the difference between the rated wind rotor speed and the wind rotor speed;

[0079] The difference is used as the speed control signal.

[0080] The present invention provides a method for tracking and controlling the speed of a floating wind turbine generator set above the rated wind speed, which first obtains the gearbox ratio and rated electromagnetic torque of the wind turbine generator set; obtains the rotor speed of the wind turbine generator set; obtains the floating base pitch angular velocity of the wind turbine generator set; and obtains the inflow wind speed of the wind turbine generator set.

[0081] Then, based on the gearbox ratio, rated electromagnetic torque, wind rotor speed, floating foundation pitch angular velocity, and inflow wind speed, the first electromagnetic torque formula is used to calculate the electromagnetic torque control signal of the wind turbine. Finally, the electromagnetic torque control signal is sent to the wind turbine controller to eliminate the limit cycle, control the electromagnetic torque of the wind turbine, and further control the wind rotor speed of the wind turbine to be constant.

[0082] The proposed method for tracking and controlling the speed of a floating wind turbine operating above rated wind speeds creatively addresses the problem of large speed oscillations by adjusting the electromagnetic torque of the wind turbine, eliminating limit cycles in the speed control system and maintaining a constant rotor speed. This helps reduce wind turbine operation and maintenance costs and extend the turbine's service life. When the wind turbine operates above rated wind speeds, i.e., throughout the entire high-speed operating range, it effectively improves rotor speed control, indirectly enhancing the economic benefits of wind power generation.

[0083] Furthermore, the speed tracking control method proposed in this invention requires no changes to the mechanical structure of the wind turbine itself or the pitch angle controller, requiring only changes to the existing electromagnetic torque control method. This method is therefore highly economical. Since only the existing electromagnetic torque control method needs to be modified, only a single nonlinear controller needs to be designed to effectively control the entire high-wind speed operating range, making the controller design more concise and efficient. Furthermore, the proposed speed tracking control method exhibits excellent dynamic performance, significantly outperforming the traditional GSPI control method with reduced gain, demonstrating its high practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0085] 1 is a flow chart of a method for tracking and controlling the speed of a floating wind turbine generator system above the rated wind speed according to an embodiment of the present invention;

[0086] 2 is a control block diagram of a method for tracking and controlling the speed of a floating wind turbine generator system above the rated wind speed according to an embodiment of the present invention;

[0087] FIG3 is a block diagram of a speed tracking control system for a floating wind turbine generator system at wind speeds above the rated wind speed according to an embodiment of the present invention. Specific embodiments

[0088] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0089] The inventors have found that, in order to prevent speed oscillation of floating wind turbines above rated wind speeds, a common method in the industry is to reduce the speed controller gain to avoid this problem.

[0090] However, this strategy does not fundamentally solve the problem, as a small-gain controller cannot quickly respond to wind speed changes and still causes speed overshoot. Current research indicates that the rotor speed oscillation problem may be caused by limit cycles.

[0091] However, the research on eliminating limit cycles through control strategies to achieve effective speed tracking is still a blank. How to eliminate limit cycles is an urgent problem to be solved.

[0092] The inventors thoroughly explored the fundamental causes of speed oscillations caused by limit cycles in floating wind turbines, conducted corresponding analysis, and after extensive research, creatively proposed a control improvement strategy based on electromagnetic torque compensation to eliminate limit cycles.

[0093] First, the inventors discovered that the model obtained by considering the two degrees of freedom of rotor rotation and floating foundation pitch in the current speed control system of floating wind turbines above rated wind speed can be expressed by the following two formulas:

[0094] In the above two equations, J is the moment of inertia of the wind wheel, Ω r is the rotor speed, v0 is the inflow wind speed, is the floating basic pitching angular velocity, β is the pitch angle, N Gear is the gearbox ratio, T e is the electromagnetic torque, T a is the aerodynamic torque, I Mass is the pitching moment of inertia of the floating foundation, L T is the tower height, M HS is the hydrostatic restoring moment, M rad is the hydrodynamic radiation torque, M diff is the hydrodynamic diffraction moment, F a It's aerodynamic thrust.

[0095] The aerodynamic power, aerodynamic torque and aerodynamic thrust expressions of floating wind turbines are shown in the following three equations:

[0096] P in the above three formulas a Indicates aerodynamic power, T a Indicates the aerodynamic torque, F a represents aerodynamic thrust, ρ is air density, R is impeller radius, is the relative wind speed, λ is the tip speed ratio, and λ is defined as:

[0097] And C p 、C q and C t They are aerodynamic power coefficient, aerodynamic torque coefficient, and aerodynamic thrust coefficient, which satisfy the following relationship:

[0098] Based on the above theory and various expressions, the inventors found that the limit cycle of the floating wind turbine is caused by the pitch motion. If equation (4) is substituted into equation (1), the following equation can be obtained:

[0099] Then the aerodynamic torque is decomposed according to the square of the relative wind speed in its expression, and the aerodynamic torque can be expanded into That is, the following formula is obtained:

[0100] Based on the above formula (9), the inventor creatively adds two parts containing the floating basic pitch angular velocity square term and the cross term to the electromagnetic torque control signal T e In the equation, let the electromagnetic torque control signal T e for:

[0101] When the loss is neglected, we can get P a =P e =N Gear Ω r T e Substituting the above formula (10) into the equation, we can get the following formula:

[0102] In the above formula, P a is the aerodynamic power of the wind turbine, is the rated aerodynamic power of the wind turbine, P e is the electromagnetic power.

[0103] Substituting the above formula (11) into the above formula (1) and formula (2) and using the Bendixon criterion for judgment, it is found that the Bendixon discriminant function is always negative within the domain of definition, that is, there is no limit cycle, indicating that the electromagnetic torque compensation strategy can eliminate the limit cycle.

[0104] Based on the above creative findings, a method for tracking and controlling the speed of a floating wind turbine generator system above the rated wind speed is proposed. As shown in FIG1 , the method comprises:

[0105] Step 101: Obtain the gearbox ratio and rated electromagnetic torque of the wind turbine.

[0106] First, obtain the gearbox ratio and rated electromagnetic torque of the floating wind turbine. Generally, these ratios are fixed and do not change after the wind turbine is manufactured and put into operation.

[0107] Step 102: Obtain the rotor speed of the wind turbine.

[0108] Secondly, it is necessary to obtain the rotor speed of the floating wind turbine. Generally, the rotor speed is not a fixed value, but may change according to the actual application situation. A better method to obtain the rotor speed includes:

[0109] The wind rotor speed is measured to obtain a measurement signal, and then the measurement signal is filtered through a low-pass filter to obtain the wind rotor speed. The low-pass filter is used to filter, where is the rated rotor speed. Generally, the rated rotor speed is also a fixed value after the wind turbine is manufactured and put into operation and does not change. Therefore, the cutoff frequency of the low-pass filter is also a fixed value, which ensures accurate rotor speed.

[0110] Step 103: Obtain the floating foundation pitch angular velocity of the wind turbine.

[0111] Step 104: Obtain the inflow wind speed of the wind turbine.

[0112] According to the above analysis, it is also necessary to obtain the floating basic pitch angular velocity and inflow wind speed of the floating wind turbine. Among them, a better method for obtaining the inflow wind speed includes:

[0113] The effective wind speed measurement value of the wind wheel is obtained by using wind measuring equipment such as laser radar or wind cup, and the effective wind speed measurement value is then used as the inflow wind speed.

[0114] Step 105: Calculate the electromagnetic torque control signal of the wind turbine using the first electromagnetic torque formula based on the gearbox ratio, the rated electromagnetic torque, the rated rotor speed, the rotor speed, the floating foundation pitch angular velocity, and the inflow wind speed.

[0115] After obtaining the above parameters, an electromagnetic torque can be calculated using the first electromagnetic torque formula based on the gearbox ratio, rated electromagnetic torque, rated wind rotor speed, wind rotor speed, floating foundation pitch angular velocity, and inflow wind speed. The electromagnetic torque can be used to generate an electromagnetic torque control signal for the wind turbine.

[0116] Among them, the first electromagnetic torque formula is:

[0117] In the above formula: T e is the electromagnetic torque corresponding to the electromagnetic torque control signal, C q is the aerodynamic torque coefficient, N Gear is the gearbox ratio, is the rated electromagnetic torque, Ω r is the rotor speed, v0 is the inflow wind speed, β is the pitch angle, ρ is the air density, R is the impeller radius, L T is the tower height, v rel is the relative wind speed, It is the floating basic pitch angular velocity.

[0118] In addition, through the above analysis, combined with formula (9), it can be seen that the electromagnetic torque control signal can also be obtained based on the aerodynamic torque compensation value. First, the aerodynamic torque compensation value is calculated; then, based on the aerodynamic torque compensation value and the gearbox ratio, the electromagnetic torque is calculated using the second electromagnetic torque formula to generate the electromagnetic torque control signal of the wind turbine.

[0119] Among them, the second electromagnetic torque formula is:

[0120] In the above formula, T a,compis the aerodynamic torque compensation value. The specific methods for calculating the aerodynamic torque compensation value include:

[0121] The aerodynamic torque of the wind turbine is split according to the square of the relative wind speed in its expression, and the aerodynamic torque T a Expands to: Right now:

[0122] Based on T a,cross and The respective expressions are calculated to obtain the aerodynamic torque compensation value

[0123] Through the above methods, electromagnetic torque can be obtained, and electromagnetic torque can eliminate limit cycles.

[0124] Step 106: Send the electromagnetic torque control signal to the wind turbine controller to eliminate the limit cycle, control the electromagnetic torque of the wind turbine, and further control the rotor speed of the wind turbine to be constant.

[0125] After obtaining the electromagnetic torque control signal, the electromagnetic torque control signal is finally sent to the wind turbine controller to eliminate the limit cycle, control the electromagnetic torque of the wind turbine, and further control the wind turbine rotor speed to be constant.

[0126] Specifically, the rotor speed control method includes calculating a speed control signal based on the rated rotor speed and the rotor speed; then controlling the rotor speed based on the speed control signal. A preferred method is to calculate the difference between the rated rotor speed and the rotor speed; using this difference as the speed control signal to control the rotor speed to maintain a constant speed.

[0127] The speed tracking control method for floating wind turbines above rated wind speeds proposed in the present invention can be more intuitively understood based on the control block diagram shown in Figure 2. While Figure 2 illustrates a blade pitch controller as a controller for controlling wind turbine speed, this does not imply that the method proposed in the present invention is only applicable to speed control systems in which a blade pitch controller is used as the controller for controlling wind turbine speed. Any controller capable of controlling wind turbine speed may be substituted.

[0128] The calculation of the aerodynamic torque compensation value T is shown in Figure 2. a,comp , and then the electromagnetic torque T is obtained e Based on the electromagnetic torque, the wind turbine can eliminate the limit cycle, so that the blade pitch controller controls the wind turbine rotor speed to be constant.

[0129] In order to demonstrate the control effect of the speed tracking control method for a floating wind turbine set above the rated wind speed proposed in this invention, a 5MW ITI Barge floating wind turbine set was used as an example for testing. The process involved is as follows:

[0130] 1) Obtain the aerodynamic torque characteristic function of the wind turbine Gearbox ratio N Gear =97, rated electromagnetic torque Rated wind wheel speed Where: Ω r is the measured value of the wind rotor speed, β is the measured value of the pitch angle, v0 is the measured value of the wind rotor effective wind speed, is the measured value of the floating basic pitch angular velocity;

[0131] 2) Use an encoder to measure the wind wheel speed and use the cutoff frequency to The wind wheel speed measurement value is obtained after the low-pass filter is applied;

[0132] 3) Use a velocity sensor to measure the pitch angular velocity of the floating foundation;

[0133] 4) Use wind speed measuring device to obtain the effective wind speed measurement value of the wind wheel;

[0134] 5) Calculate the electromagnetic torque control signal based on the above electromagnetic torque formula;

[0135] 6) Input the obtained electromagnetic torque control signal to the floating wind turbine controller.

[0136] The proposed method was simulated and verified using the dynamics simulation software OpenFAST. The operating range of a 5MW wind turbine in the high wind speed range is 11.4m / s to 25m / s. To evaluate the control performance of the proposed method across this high wind speed range, simulation tests were conducted under the following typical wind conditions: an average wind speed of 18m / s, a turbulence intensity of 10%, and irregular wave heights of 1.265m and a period of 7.5s.

[0137] To measure the control performance of the proposed method, the commonly used gain-scheduled proportional-integral control method (GSPI) and the detuned gain-scheduled proportional-integral control method (D-GSPI) were used as benchmarks. The control performance of the proposed method was compared and analyzed in combination with the GSPI method.

[0138] The control performance indicator considered is the mean square error of the rotor speed. Under typical wind conditions, the control performance comparison results of the proposed method with the traditional GSPI and D-GSPI control methods are shown in the following table:

[0139] In the above table, the RMSD represents the RMSD of the rotor speed. This shows that in the entire high wind speed operating range, the speed tracking control method for floating wind turbines proposed in this invention can effectively improve the rotor speed control effect at wind speeds above the rated speed.

[0140] Based on the above-mentioned speed tracking control method for a floating wind turbine generator set at wind speeds above the rated wind speed, the present invention further proposes a speed tracking control system for a floating wind turbine generator set at wind speeds above the rated wind speed. Referring to the block diagram shown in FIG3 , the speed tracking control system comprises:

[0141] A basic parameter module 310 is used to obtain the gearbox ratio and rated electromagnetic torque of the wind turbine;

[0142] A rotation speed module 320 is used to obtain the rotation speed of the rotor of the wind turbine generator set;

[0143] The pitch angular velocity module 330 is used to obtain the floating basic pitch angular velocity of the wind turbine;

[0144] An inflow wind speed module 340 is used to obtain the inflow wind speed of the wind turbine;

[0145] an electromagnetic torque calculation module 350 for calculating an electromagnetic torque control signal of the wind turbine generator system using a first electromagnetic torque formula based on the gearbox ratio, the rated electromagnetic torque, the rotor speed, the floating foundation pitch angular velocity, and the inflow wind speed;

[0146] The electromagnetic torque control module 360 ​​is configured to send the electromagnetic torque control signal to the wind turbine controller to eliminate the limit cycle, control the electromagnetic torque of the wind turbine, and further control the rotor speed of the wind turbine to be constant;

[0147] Wherein, the first electromagnetic torque formula is:

[0148] In the above formula: T e is the electromagnetic torque corresponding to the electromagnetic torque control signal, C q is the aerodynamic torque coefficient, N Gear is the gearbox ratio, is the rated electromagnetic torque, Ω e is the rotor speed, v0 is the inflow wind speed, β is the pitch angle, ρ is the air density, R is the impeller radius, L T is the tower height, v rel is the relative wind speed, It is the floating basic pitch angular velocity.

[0149] Optionally, the rotation speed module 320 includes:

[0150] A measuring unit, used to measure the speed of the wind wheel to obtain a measurement signal;

[0151] The filtering unit is used to filter the measurement signal through a low-pass filter to obtain the wind wheel speed.

[0152] Optionally, the inflow wind speed module 340 is specifically used to:

[0153] Obtain the effective wind speed measurement value of the wind rotor through wind measuring equipment;

[0154] The effective wind speed measurement value is used as the inflow wind speed.

[0155] Optionally, the filtering unit is specifically configured to:

[0156] The measurement signal is passed through a cutoff frequency of The low-pass filter is used to filter, where is the rated wind wheel speed.

[0157] Optionally, the speed tracking and control system further includes:

[0158] A pneumatic torque compensation value module is used to calculate the pneumatic torque compensation value;

[0159] a torque calculation module, configured to calculate an electromagnetic torque control signal of the wind turbine generator set using a second electromagnetic torque formula based on the aerodynamic torque compensation value and the gearbox ratio;

[0160] Among them, the second electromagnetic torque formula is:

[0161] In the above formula, T a,comp is the aerodynamic torque compensation value.

[0162] Optionally, the aerodynamic torque compensation value module is specifically used to:

[0163] The aerodynamic torque of the wind turbine is decomposed according to the square of the relative wind speed in its expression, and the aerodynamic torque T a Expands to: Right now:

[0164] Based on T a,cross and The respective expressions are calculated to obtain the aerodynamic torque compensation value

[0165] When the loss is neglected, since P a=P e =N Gear Ω r T e , then substituting the first electromagnetic torque formula into the equation, we can get the following formula:

[0166] In the above formula, P a is the aerodynamic power of the wind turbine, is the rated aerodynamic power of the wind turbine, P e is the electromagnetic power;

[0167] Substituting the above formula into a model formula obtained by considering two degrees of freedom of rotor rotation and floating foundation pitch of the floating wind turbine at a wind speed above the rated speed, and using the Bendixon criterion to make a judgment, it is determined that the Bendixon discriminant function is always negative within the definition domain, that is, the limit cycle does not exist, so that the limit cycle is eliminated when the wind turbine is controlled by the electromagnetic torque control signal;

[0168] Wherein, the model formula is:

[0169] In the above two equations, J is the moment of inertia of the wind wheel, I Mass is the pitching moment of inertia of the floating foundation, M HS is the hydrostatic restoring moment, M rad is the hydrodynamic radiation torque, M diff is the hydrodynamic diffraction moment, F a It's aerodynamic thrust.

[0170] Optionally, the speed tracking and control system further includes:

[0171] A speed calculation module, configured to calculate a speed control signal based on the rated wind rotor speed and the wind rotor speed;

[0172] The speed control module is used to control the speed of the wind wheel according to the speed control signal.

[0173] Optionally, the rotation speed calculation module is specifically configured to:

[0174] Calculating the difference between the rated wind rotor speed and the wind rotor speed;

[0175] The difference is used as the speed control signal.

[0176] In summary, the speed tracking control method of the floating wind turbine of the present invention above the rated wind speed first obtains the gearbox ratio and rated electromagnetic torque of the wind turbine; obtains the rotor speed of the wind turbine; obtains the floating basic pitch angular velocity of the wind turbine; and obtains the inflow wind speed of the wind turbine.

[0177] Then, based on the gearbox ratio, rated electromagnetic torque, wind rotor speed, floating foundation pitch angular velocity, and inflow wind speed, the first electromagnetic torque formula is used to calculate the electromagnetic torque control signal of the wind turbine. Finally, the electromagnetic torque control signal is sent to the wind turbine controller to eliminate the limit cycle, control the electromagnetic torque of the wind turbine, and further control the wind rotor speed of the wind turbine to be constant.

[0178] The proposed method for tracking and controlling the speed of a floating wind turbine operating above rated wind speeds creatively addresses the problem of large speed oscillations by adjusting the electromagnetic torque of the wind turbine, eliminating limit cycles in the speed control system and maintaining a constant rotor speed. This helps reduce wind turbine operation and maintenance costs and extend the turbine's service life. When the wind turbine operates above rated wind speeds, i.e., throughout the entire high-speed operating range, it effectively improves rotor speed control, indirectly enhancing the economic benefits of wind power generation.

[0179] Furthermore, the speed tracking control method proposed in this invention requires no changes to the mechanical structure of the wind turbine itself or the pitch angle controller, requiring only changes to the existing electromagnetic torque control method. This method is therefore highly economical. Since only the existing electromagnetic torque control method needs to be modified, only a single nonlinear controller needs to be designed to effectively control the entire high-wind speed operating range, making the controller design more concise and efficient. Furthermore, the proposed speed tracking control method exhibits excellent dynamic performance, significantly outperforming the traditional GSPI control method with reduced gain, demonstrating its high practicality.

[0180] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic creative concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0181] Finally, it should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or terminal device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or terminal device that includes the element.

[0182] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are protected by the present invention.

Claims

1. A method for tracking and controlling the speed of a floating wind turbine generator set above the rated wind speed, characterized in that: The speed tracking control method comprises: Obtaining the gearbox ratio and rated electromagnetic torque of the wind turbine generator set; Obtaining a wind rotor speed of the wind turbine; Obtaining a floating basic pitch angular velocity of the wind turbine; Obtaining an inflow wind speed of the wind turbine generator set; Calculating the electromagnetic torque control signal of the wind turbine generator set using a first electromagnetic torque formula based on the gearbox ratio, the rated electromagnetic torque, the wind rotor speed, the floating foundation pitch angular velocity, and the inflow wind speed; Sending the electromagnetic torque control signal to the wind turbine controller to eliminate the limit cycle, control the electromagnetic torque of the wind turbine, and further control the rotor speed of the wind turbine to be constant; Among them, the first electromagnetic torque formula is: In the above formula: T e is the electromagnetic torque corresponding to the electromagnetic torque control signal, C q is the aerodynamic torque coefficient, N Gear is the gearbox ratio, is the rated electromagnetic torque, Ω r is the rotor speed, v0 is the inflow wind speed, β is the pitch angle, ρ is the air density, R is the impeller radius, L T is the tower height, v rel is the relative wind speed, It is the floating basic pitch angular velocity.

2. The speed tracking control method according to claim 1, characterized in that: Obtaining the rotor speed of the wind turbine generator set includes: Measuring the wind wheel rotation speed to obtain a measurement signal; The wind wheel speed is obtained by filtering the measurement signal through a low-pass filter.

3. The speed tracking control method according to claim 1, characterized in that: Obtaining the inflow wind speed of the wind turbine generator set includes: Obtain the effective wind speed measurement value of the wind rotor through the wind measuring equipment; The effective wind speed measurement value is used as the inflow wind speed.

4. The speed tracking control method according to claim 2, characterized in that: The measurement signal is filtered through a low-pass filter, comprising: The measurement signal is passed through a cutoff frequency of The low-pass filter is used to filter, where is the rated wind rotor speed.

5. The speed tracking control method according to claim 1, characterized in that: The speed tracking control method further includes: Calculate the aerodynamic torque compensation value; Based on the aerodynamic torque compensation value and the gearbox ratio, calculating the electromagnetic torque control signal of the wind turbine generator set using a second electromagnetic torque formula; Wherein, the second electromagnetic torque formula is: In the above formula, T a,comp is the aerodynamic torque compensation value.

6. The speed tracking control method according to claim 5, characterized in that: Calculates aerodynamic torque compensation values, including: The aerodynamic torque of the wind turbine is decomposed according to the square term of the relative wind speed in its expression, and the aerodynamic torque T a Expands to: Right now: Based on T a,cross and The respective expressions are calculated to obtain the aerodynamic torque compensation value 7. The speed tracking control method according to claim 1, characterized in that: When the loss is ignored, due to P a =P e =N Gear Ω r T e , then substituting the first electromagnetic torque formula into the following formula: In the above formula, P a is the aerodynamic power of the wind turbine, is the rated aerodynamic power of the wind turbine, P e is the electromagnetic power; Substitute the above formula into the model formula obtained by considering the two degrees of freedom of rotor rotation and floating foundation pitch of the floating wind turbine at a wind speed above the rated wind speed, and use the Bendixon criterion to make a judgment, and determine that the Bendixon discriminant function is always negative in the definition domain, that is, the limit cycle does not exist, so that when the wind turbine is controlled by the electromagnetic torque control signal, the limit cycle is eliminated; Wherein, the model formula is: In the above two equations, J is the moment of inertia of the wind wheel, I Mass is the pitch moment of inertia of the floating foundation, M HS is the hydrostatic restoring moment, M rad is the hydrodynamic radiation moment, M diff is the hydrodynamic diffraction moment, F a It's pneumatic thrust.

8. The speed tracking control method according to claim 1, characterized in that: The speed tracking control method further includes: Based on the rated wind rotor speed and the wind rotor speed, a speed control signal is obtained by calculation; The wind wheel speed is controlled according to the speed control signal.

9. The speed tracking control method according to claim 8, characterized in that: Based on the rated wind rotor speed and the wind rotor speed, a speed control signal is obtained by calculation, including: Obtaining a difference between the rated wind rotor speed and the wind rotor speed; The difference is used as the rotation speed control signal.

10. A speed tracking control system for floating wind turbines above rated wind speed, characterized in that: The speed tracking control system comprises: A basic parameter module, used to obtain the gearbox ratio and rated electromagnetic torque of the wind turbine; A rotation speed module, used to obtain the rotation speed of a wind rotor of the wind turbine; A pitch angular velocity module, used for obtaining a floating basic pitch angular velocity of the wind turbine; An inflow wind speed module, used to obtain the inflow wind speed of the wind turbine; an electromagnetic torque calculation module, configured to calculate the electromagnetic torque control signal of the wind turbine generator set by using a first electromagnetic torque formula based on the gearbox ratio, the rated electromagnetic torque, the wind rotor speed, the floating foundation pitch angular velocity, and the inflow wind speed; An electromagnetic torque control module, used for sending the electromagnetic torque control signal to the wind turbine controller to eliminate the limit cycle, control the electromagnetic torque of the wind turbine, and further control the rotor speed of the wind turbine to be constant; Among them, the first electromagnetic torque formula is: In the above formula: T e is the electromagnetic torque corresponding to the electromagnetic torque control signal, C q is the aerodynamic torque coefficient, N Gear is the gearbox ratio, is the rated electromagnetic torque, Ω e is the rotor speed, v0 is the inflow wind speed, β is the pitch angle, ρ is the air density, R is the impeller radius, L T is the tower height, v rel is the relative wind speed, It is the floating basic pitch angular velocity.

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