Method and device for coordinated control of ultimate and fatigue loads for floating wind turbines

Abstract

The application discloses a kind of floating wind turbine limit and fatigue load cooperative control method and device, method includes real-time acquisition platform posture, wind wheel operating parameter, blade root bending moment, azimuth angle and pitch angle data;Again, coordinate transformation is carried out in combination with blade root bending moment, azimuth angle and pitch angle, and wind wheel yawing moment and pitching moment under fixed hub coordinate system are obtained by solving;While the platform pitch angle is carried out coordinate conversion and high-pass filtering, and low-frequency interference is filtered out and mutual influence with main control system is avoided;By calculating limit load threshold value degree index, the component pitch angle of independent variable pitch mechanism is dynamically adjusted, the adjusted pitch angle is superimposed with main control reference pitch angle, total pitch control quantity is generated and is issued to variable pitch actuator.This method does not need to install high-precision sensor and high-power equipment, can inhibit fatigue load and limit load, solve the problem that traditional strategy control target is single and working condition adaptability is poor, guarantee unit safe and stable operation.

Description

Technical Field

[0001] This invention belongs to the field of offshore wind turbine control technology, specifically relating to a method and device for coordinated control of ultimate and fatigue loads of floating wind turbines. Background Technology

[0002] Floating wind turbines operate in extreme marine environments where wind, waves, and currents are coupled. The platform's six-degree-of-freedom motion is highly coupled with the turbine's aerodynamics, hydrodynamics, and structural dynamics. Compared to onshore and stationary offshore wind turbines, the low-frequency, large-amplitude pitching and swaying motion of floating platforms significantly increases tower load, blade root bending moment, and transmission chain torque fluctuations, exacerbating structural fatigue damage. Furthermore, extreme gusts, wind shear, and wave resonance can easily trigger peak ultimate loads, leading to ultimate damage to mechanical components and threatening the safe operation of the turbine.

[0003] Existing control technologies are mostly optimized for fatigue loads or ultimate loads separately. Fatigue load reduction often employs independent pitch control and vibration suppression control, while ultimate protection often uses strategies such as pre-aiming pitch opening and model predictive control. However, existing solutions generally have shortcomings: there is a lack of a unified coordination mechanism between fatigue and ultimate control targets, resulting in poor adaptability to operating conditions; they rely on equipment such as lidar and high-computing-power models, leading to high engineering application costs and low reliability; protection triggering depends on a single threshold, which is prone to false triggering or protection lag. Currently, there is still a lack of control methods that are simple in structure, computationally efficient, and capable of dynamically and collaboratively balancing ultimate and fatigue loads under all operating conditions, making it difficult to meet the safe and stable operation requirements of floating wind turbines. Summary of the Invention

[0004] The purpose of this invention is to provide a method and device for coordinated control of ultimate and fatigue loads of floating wind turbine units, in order to solve the technical defects of existing technologies, such as inability to coordinate and regulate ultimate loads and fatigue loads, poor adaptability to operating conditions, high equipment cost, and susceptibility to false triggering or lag in protection.

[0005] To achieve the above objectives, the present invention employs the following technical solutions.

[0006] In a first aspect, this application provides a method for coordinated control of ultimate and fatigue loads of a floating wind turbine, comprising: Real-time acquisition of platform attitude, wind turbine operating parameters, blade root bending moment, azimuth angle and pitch angle data output by the unit's sensors; Based on the blade root bending moment, azimuth angle and pitch angle data, coordinate transformation is performed to obtain the wind turbine yaw moment and pitch moment in a fixed hub coordinate system. Based on the platform's attitude, coordinate transformation and high-pass filtering are performed on the pitch angle to filter out low-frequency components and avoid interference with the main control system. Based on the wind turbine speed, the platform pitch angle, the blade root bending moment, the yaw moment, and the pitch moment, calculate the corresponding ultimate load exceeding threshold index; Using the aforementioned limit load exceeding threshold index, the zero component, yaw component, and pitch component pitch angle of the independent pitch mechanism are dynamically adjusted. The adjusted pitch angles of each component are superimposed on the reference pitch angle output by the main control unit, and the total pitch control quantity is output to the pitch actuator.

[0007] Furthermore, the platform attitude is acquired by attitude sensors installed on the floating platform, including the platform pitch angle and the platform roll angle; The wind turbine operating parameters are collected by the unit's main control system and hub encoder, including wind turbine speed and wind turbine yaw angle; The blade root bending moment is collected by a blade root bending moment sensor installed at the root of each blade, including the blade root flapping bending moment and the blade root swinging bending moment.

[0008] Furthermore, the coordinate transformation adopts the Park coordinate transformation, which specifically includes: calculating the out-of-plane blade root bending moment component based on the blade root bending moment and the pitch angle, and transforming the bending moment component to a fixed hub coordinate system in combination with the blade azimuth angle to obtain the wind turbine yaw moment and wind turbine pitch moment.

[0009] Furthermore, a coordinate transformation is performed on the pitch angle, specifically including: By combining the wind turbine yaw angle, the platform pitch angle is uniformly mapped to a fixed hub coordinate system to obtain the platform pitch angle before filtering.

[0010] Furthermore, the high-pass filter uses the platform's pitch mode natural frequency as the cutoff frequency.

[0011] Furthermore, the index of the degree to which the ultimate load exceeds the threshold specifically includes: The over-threshold indicators corresponding to wind turbine speed, platform pitch angle, blade root bending moment, wind turbine yaw moment, and wind turbine pitch moment.

[0012] Furthermore, the over-threshold indicators corresponding to the wind turbine speed, platform pitch angle, blade root bending moment, wind turbine yaw moment, and wind turbine pitch moment are multiplied to obtain the comprehensive over-limit degree, and the independent pitch control gain is adaptively adjusted according to the comprehensive over-limit degree.

[0013] Furthermore, the zero-component pitch angle is adjusted in a closed loop based on the rotor speed and the filtered platform pitch angle; The yaw component pitch angle and the pitch component pitch angle are respectively adjusted in a closed loop based on the wind turbine yaw moment and wind turbine pitch moment, and the control gain is adaptively corrected. The total pitch control value is generated by superimposing the reference pitch angle, the zero component pitch angle, the yaw component pitch angle, and the pitch component pitch angle, and is output to the pitch actuator.

[0014] A second aspect of this application provides a coordinated control system for ultimate and fatigue loads of a floating wind turbine, comprising: The data acquisition module is used to collect platform attitude, wind turbine operating parameters, blade root bending moment, azimuth angle and pitch angle data output by the unit's sensors in real time; The torque calculation module is used to perform coordinate transformation based on the blade root bending moment, azimuth angle and pitch angle data to obtain the wind turbine yaw moment and pitch moment in a fixed hub coordinate system. The attitude processing module is used to perform coordinate transformation and high-pass filtering on the pitch angle according to the platform attitude, filter out low-frequency components and avoid interference with the main control system. The index calculation module is used to calculate the corresponding ultimate load exceeding threshold index based on the wind turbine speed, the platform pitch angle, the blade root bending moment, the yaw moment and the pitch moment; The pitch adjustment module is used to dynamically adjust the zero component, yaw component, and pitch component pitch angle of the independent pitch mechanism using the limit load exceeding the threshold index. The control output module is used to superimpose the adjusted pitch angle components with the reference pitch angle output by the main control unit, and output the total pitch control quantity to the pitch actuator.

[0015] In a third aspect, this application provides a computer product that stores a computer program, which, when executed by a processor, implements the above-described method for coordinated control of limit and fatigue loads of a floating wind turbine.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This method utilizes existing sensors on the turbine to collect various types of operational data. Through coordinate transformation, attitude filtering, load over-limit index calculation, and independent pitch layer adjustment, it finally synthesizes the total pitch control quantity to achieve closed-loop control, connecting the entire process of data processing and load control. It can simultaneously suppress fatigue load and ultimate load of floating wind turbines without the need for additional high-precision sensing equipment and high-computing units. The overall logic is simple, the computing efficiency is high, and the adaptability to all operating conditions is strong. It effectively solves the problems of single target and poor adaptability of traditional control strategies, ensuring the long-term safe and stable operation of the turbine.

[0017] 2. Clearly define the acquisition devices and specific parameter types for various monitoring data, and classify the sub-indicators of platform attitude, wind turbine operating parameters, and blade root bending moment, ensuring clear data sources and comprehensive monitoring dimensions. Relying on attitude sensors, hub encoders, and blade root bending moment sensors to acquire signals, the system can accurately capture the motion state of the floating platform, wind turbine operating conditions, and blade load changes. This provides accurate and complete raw data support for subsequent coordinate transformations, filtering calculations, and load index calculations, improving the data foundation reliability and operational stability of the overall control scheme.

[0018] 3. The Park coordinate transformation is used to calculate the bending moment to torque. First, the out-of-plane bending moment components of the wind turbine are solved, and then the coordinate system transformation is completed by combining the azimuth angle. This transformation method is a mature algorithm in the wind power field. The calculation model is simple and the calculation time is short. It can accurately convert the local blade root bending moment into the overall torque parameter under the fixed hub coordinate system, ensuring the accuracy of the torque calculation results and avoiding control inaccuracies caused by coordinate transformation deviations. It provides accurate torque data support for subsequent load over-limit judgment and pitch adjustment.

[0019] 4. A coordinate system mapping is completed for the platform's pitch angle. Combined with the wind turbine yaw angle, the pitch angle is transformed to a fixed hub coordinate system, unifying the data benchmark. This eliminates signal deviations caused by different coordinate systems, ensuring that the platform's attitude data and the wind turbine's operating data are under the same computational system. This guarantees the consistency of data in subsequent filtering and load index calculations, effectively avoiding signal distortion caused by inconsistencies in coordinate systems, and improving the accuracy of attitude data processing and subsequent control processes.

[0020] 5. This solution limits the high-pass filtering to the platform's natural pitch mode frequency as the cutoff frequency, which can accurately filter out the platform's low-frequency pitch components. This effectively reduces signal interference caused by the large low-frequency motion of the floating platform while retaining effective control signals. At the same time, it avoids control coupling and mutual interference between the filtering operation and the unit's original main control system. The filtering parameters match the inherent characteristics of the unit, and the filtering effect is highly targeted, further improving the quality of attitude signals and strengthening the anti-interference capability of the overall control strategy.

[0021] 6. Multi-dimensional indicators can comprehensively characterize the current load operating status of the unit, fully reflect the load changes under wind-wave-current coupled disturbances, change the traditional single signal and single threshold judgment mode, and can timely identify various load over-limit conditions, improve the comprehensiveness and timeliness of extreme load risk identification, and reduce protection omissions.

[0022] 7. This scheme performs a product operation on multiple over-threshold indicators to obtain a comprehensive over-limit degree, and uses this to adaptively adjust the pitch control gain. It can integrate multi-dimensional load over-limit states into a unified evaluation standard, realize the organic unity of fatigue load and ultimate load control objectives, and dynamically adjust the control intensity according to the severity of load over-limit.

[0023] 8. Independent closed-loop control logic is divided for different component pitch angles. The zero component, yaw component, and pitch component each perform their own functions and adaptively correct the gain. Finally, the reference pitch angle is superimposed to form the total control quantity. The layered control mode can suppress various loads caused by platform motion and wind turbine torque, and achieve a smooth transition between fatigue load suppression and ultimate load protection. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 The flowchart of a method for coordinated control of ultimate and fatigue loads of a floating wind turbine provided by the present invention is shown. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0027] To address the technical deficiencies mentioned in the background section, this embodiment provides a method and apparatus for coordinated control of ultimate and fatigue loads of floating wind turbine generators. The invention will be further described in detail below with reference to the accompanying drawings: In a first aspect, the present invention provides a method for coordinated control of ultimate and fatigue loads in floating wind turbine generators, such as... Figure 1 As shown, it includes: S101. Real-time acquisition of platform attitude, wind turbine operating parameters, blade root bending moment, azimuth angle and pitch angle data output by the unit's sensors; For example, the platform attitude is acquired in real time by attitude sensors installed on the floating platform, specifically including the platform pitch angle and platform roll angle; the turbine operating parameters are acquired by the unit's main control system and hub encoder, specifically including the turbine speed and turbine yaw angle; the blade root bending moment is acquired by blade root bending moment sensors installed at the root of each blade, specifically including blade root flapping bending moment and blade root oscillation bending moment. The system synchronously acquires the real-time azimuth angle and pitch angle of each blade, defining the azimuth angle as 0° when the blade is vertically upward, providing complete raw data for subsequent coordinate transformation, torque calculation, and load index calculation.

[0028] Specifically, real-time monitoring of key performance indicators of floating wind turbines, including the pitch angle of the floating platform. Platform roll angle Wind turbine speed Wind turbine yaw angle The waving moment of each leaf root , , The bending moment of each leaf root in the array , , Azimuth angle of each blade , , Pitch angle of each blade , , It is agreed that the azimuth angle is 0 when the blade rotates to the vertically upward position.

[0029] S102. Based on the blade root bending moment, azimuth angle and pitch angle data, perform coordinate transformation to obtain the wind turbine yaw moment and pitch moment in a fixed hub coordinate system. For example, the calculation is performed using Park coordinate transformation. Based on the blade root bending moment and the pitch angle, the out-of-plane blade root bending moment component is calculated. Then, combined with the blade azimuth angle, the bending moment component is transformed to a fixed hub coordinate system. In this way, the yaw moment and pitch moment of the wind turbine are calculated, which can provide accurate torque parameter support for the subsequent load state determination process.

[0030] Specifically, based on the flapping moments of each blade root obtained from S101 , , bending moment of each leaf root array , , Real-time pitch angle of each blade , , Azimuth signals of each blade , , The yaw moment of the wind turbine in a fixed hub coordinate system is obtained by using coordinate transformation. Windmill pitch moment .

[0031] Based on the obtained flapping moments of each leaf root , , bending moment of each leaf root array , , and the real-time pitch angle of each blade. , , Calculate the root bending moment component of each blade in the out-of-plane direction, denoted as . , , .

[0032]

[0033] Based on the blade root bending moment components obtained above in the out-of-plane direction of the wind turbine, , , The obtained blade azimuth angle is denoted as , , Using Park coordinate transformation to determine the yaw moment of the wind turbine in a fixed hub coordinate system Windmill pitch moment :

[0034] in, , and The zero component of blade root bending moment, wind turbine yaw moment, and wind turbine pitch moment are defined in a fixed hub coordinate system. S103. Perform coordinate transformation and high-pass filtering on the pitch angle according to the platform attitude to filter out low-frequency components and avoid interference with the main control system. For example, the pitch angle is first transformed into coordinates, and then the platform pitch angle is mapped to a fixed hub coordinate system in combination with the wind turbine yaw angle to obtain the platform pitch angle before filtering, thus completing the data benchmark unification.

[0035] Subsequently, high-pass filtering is performed. This filter uses the platform's natural pitch mode frequency as the cutoff frequency, which can accurately filter out the low-frequency pitch components generated by the platform's motion, eliminate interference signals from the marine environment, avoid control coupling with the unit's main control system, and output a stable and reliable pitch angle signal to ensure the accuracy of subsequent load index calculations.

[0036] Specifically, based on the obtained wind turbine yaw angle Platform pitch angle Platform roll angle Considering cabin yaw, the platform pitch angle before and after filtering in a fixed hub coordinate system is calculated using coordinate transformation and high-pass filtering. and .

[0037] Calculate the platform pitch angle before filtering in a fixed hub coordinate system using coordinate transformation. :

[0038] A high-pass filter is used to calculate the platform pitch angle in a fixed hub coordinate system after filtering, in order to eliminate the interference between the low-frequency pitch angle component and the original main control. The filter sensing function is:

[0039] in, To determine the filtered platform pitch angle in a fixed hub coordinate system, For the Laplace operator, The platform's pitch mode natural frequency.

[0040] Based on the obtained wind turbine speed signal, the obtained blade root flapping moment signal, and the obtained platform pitch angle before filtering in the fixed hub coordinate system The obtained wind turbine yaw moment and wind turbine pitch moment signals are used to calculate the performance indicators of the ultimate load exceeding the threshold for speed, platform pitch angle, blade root bending moment, wind turbine yaw moment, and wind turbine pitch moment.

[0041]

[0042] in, , , , and These are the limit thresholds for rotational speed, platform pitch angle, blade root bending moment, rotor yaw moment, and rotor pitch moment, respectively.

[0043] This indicates taking the maximum value. , , , and These are performance indicators for the degree of exceeding the ultimate load threshold, namely, rotational speed, platform pitch angle, blade root bending moment, rotor yaw moment, and rotor pitch moment. When these values ​​are 1, it means that the ultimate load threshold has not been reached. When they exceed 1, it means that the ultimate load threshold has been reached. The larger the value, the greater the degree of exceeding the threshold.

[0044] S104. Using the limit load exceeding the threshold index, dynamically adjust the zero component, yaw component, and pitch component pitch angle of the independent pitch mechanism. For example, the ultimate load exceeding threshold index includes the exceeding threshold indexes corresponding to the rotor speed, platform pitch angle, blade root bending moment, rotor yaw moment, and rotor pitch moment. The comprehensive exceeding degree is obtained by multiplying the above indexes, and the independent pitch control gain is adaptively adjusted accordingly. Among them, the zero component pitch angle is combined with the rotor speed and the filtered platform pitch angle for closed-loop adjustment to smoothly suppress fatigue load. The yaw and pitch component pitch angles are respectively adjusted according to the stress moment in closed-loop adjustment, and the adaptive gain is used to adapt to different operating conditions to achieve dynamic optimization of each pitch angle component.

[0045] Specifically, based on the performance index of the ultimate load exceeding the threshold obtained in S104, the platform pitch angle after filtering in the fixed hub coordinate system obtained in S103 is... The wind turbine speed signal obtained by S101 Calculate the zero-component pitch angle of independent pitch control in a fixed hub coordinate system. :

[0046] in, The rated speed of the wind turbine. and These are the proportional coefficient and integral coefficient for speed compensation, respectively. and The proportional and differential coefficients for platform pitch angle compensation; multiplying the performance indicators for each ultimate load exceeding the threshold. This yields a comprehensive assessment considering the exceedance of these key factors to the limit threshold. When none of the key factors exceed the limit threshold, Then, the zero-component control loop of the independent pitch control is fatigue load control based on speed and platform pitch angle. When any one of the key factors exceeds the limit threshold, The zero-component control loop of independent pitch control achieves ultimate load control by increasing the gain, and the gain increase ratio is directly related to the degree to which various factors exceed the limit threshold.

[0047] Therefore, the proposed method achieves a smooth transition in the control of ultimate load and fatigue load, and comprehensively considers the degree of exceeding the limit value of multiple key indicators, thus realizing multi-objective control.

[0048] Based on the obtained performance index of the degree of exceedance of the ultimate load and the wind turbine yaw moment based on the obtained fixed hub coordinate system Calculate the yaw component pitch angle of independent pitch control in a fixed hub coordinate system. :

[0049] in, and These are the proportional and integral coefficients for wind turbine pitching moment compensation, respectively. (The remaining text appears to be incomplete and requires further context.) Multiply the performance indicators of the degree of exceeding the threshold of each ultimate load. This yields a comprehensive assessment of the degree to which these key factors exceed the limit threshold. This indicates that when the rotor speed, blade root bending moment, platform pitch, and rotor pitch moment trigger the ultimate load control, the control gain of the yaw component and pitch angle element is reduced accordingly, and the control gain of the yaw component and pitch angle element is removed. The reason for this is that the yaw component pitch angle control loop can help reduce the ultimate load of the wind turbine yaw moment.

[0050] Based on the obtained performance index of the degree of exceedance of the ultimate load and the wind turbine pitching moment based on the obtained fixed hub coordinate system Calculate the pitch component pitch angle of independent pitch control in a fixed hub coordinate system. :

[0051] in, and These are the proportional and integral coefficients for wind turbine pitching moment compensation, respectively. (The remaining text appears to be incomplete and requires further context.) Multiply the performance indicators of the degree of exceeding the threshold of each ultimate load. This yields a comprehensive assessment of the degree to which these key factors exceed the limit threshold. This indicates that when the rotor speed, blade root bending moment, and rotor pitch moment trigger the ultimate load control, the control gain of the pitch component and pitch angle element is reduced accordingly, and the control is removed. The reason for this is that the pitch component pitch angle control loop can help reduce the ultimate load of the wind turbine pitch moment and the platform pitch motion.

[0052] S105. The adjusted pitch angles of each component are superimposed with the reference pitch angle output by the main control unit, and the total pitch control quantity is output to the pitch actuator.

[0053] For example, the zero-component pitch angle is adjusted in a closed loop based on the rotor speed and the filtered platform pitch angle, while the yaw component pitch angle and pitch component pitch angle are adjusted in a closed loop based on the rotor yaw moment and rotor pitch moment, respectively, and the control gain is adaptively corrected.

[0054] The adjusted pitch angle components are superimposed with the reference pitch angle output by the main control unit to generate the total pitch control value, which is then sent to the pitch actuator. This composite control mode can dynamically adapt to marine coupled operating conditions, while simultaneously achieving fatigue load suppression and ultimate load protection, thus completing the unit's load-coordinated closed-loop control.

[0055] Specifically, the reference pitch angle control quantity is calculated using the reference master control algorithm of the floating wind turbine. Since the algorithm is mature, it will not be elaborated here.

[0056] Based on the obtained 0-component pitch angle Pitch component pitch angle Yaw component pitch angle The obtained reference pitch angle control quantity The obtained blade azimuth angle is denoted as , , Calculate the total pitch angle setpoint:

[0057] in, , and These are the set values ​​for the total pitch angle of each blade.

[0058] A second aspect of the present invention provides a coordinated control system for ultimate and fatigue loads of a floating wind turbine, comprising: The data acquisition module is used to collect platform attitude, wind turbine operating parameters, blade root bending moment, azimuth angle and pitch angle data output by the unit's sensors in real time; The torque calculation module is used to perform coordinate transformation based on the blade root bending moment, azimuth angle and pitch angle data to obtain the wind turbine yaw moment and pitch moment in a fixed hub coordinate system. The attitude processing module is used to perform coordinate transformation and high-pass filtering on the pitch angle according to the platform attitude, filter out low-frequency components and avoid interference with the main control system. The index calculation module is used to calculate the corresponding ultimate load exceeding threshold index based on the wind turbine speed, the platform pitch angle, the blade root bending moment, the yaw moment and the pitch moment; The pitch adjustment module is used to dynamically adjust the zero component, yaw component, and pitch component pitch angle of the independent pitch mechanism using the limit load exceeding the threshold index. The control output module is used to superimpose the adjusted pitch angle components with the reference pitch angle output by the main control unit, and output the total pitch control quantity to the pitch actuator.

[0059] In this system, the data acquisition module collects various raw operating data, attitude data, and load data in real time during the operation of the floating wind turbine. During the actual operation of the floating wind turbine, the platform is subjected to six degrees of freedom motion by the continuous action of waves, currents, and wind. The rotor speed, blade attitude, and blade load will also change dynamically in real time with the external operating conditions. Only by achieving multi-dimensional, high-frequency, and uninterrupted data acquisition can the control system accurately perceive the real-time operating status of the unit.

[0060] The data collected by this module includes platform attitude, wind turbine operating parameters, blade root bending moment, blade azimuth angle, and blade pitch angle. The module integrates the original attitude sensor, hub encoder, and blade root bending moment sensor of the unit, and also interfaces with the data interface of the original main control system of the unit. There is no need to install a large number of new sensing devices, which effectively controls the equipment modification cost and the difficulty of later maintenance.

[0061] Among them, the attitude sensor used to detect the platform's attitude is fixedly installed on the main structure of the floating platform. It can capture the platform's motion state in the marine environment in real time and output the platform's pitch angle and roll angle data. These two types of angle parameters can intuitively reflect the sway amplitude and motion trend of the floating platform and assess the impact of the platform's motion on the unit's load.

[0062] The wind turbine operating parameters are mainly collected by the main control system of the unit and the hub encoder. The main control system provides real-time feedback on the wind turbine's real-time speed, while the hub encoder synchronously collects the wind turbine's yaw angle. The wind turbine speed directly determines the magnitude of the unit's aerodynamic load, while the wind turbine yaw angle represents the relative position of the wind turbine to the direction of the incoming wind. These two types of parameters are necessary prerequisites for coordinate unification and load calculation.

[0063] The blade root bending moment is collected by blade root bending moment sensors arranged at the root of each blade. The blade root flapping bending moment and blade root oscillation bending moment generated during blade operation can be detected. As the load concentration area, the bending moment value of the blade root is a key indicator for judging blade fatigue damage and ultimate load impact.

[0064] In addition, the module also synchronously collects the real-time azimuth angle and pitch angle of each blade. The blade azimuth angle is used to characterize the position of the blade in the plane of rotation, while the pitch angle is a direct control parameter of the pitch mechanism. Both types of signals are used throughout the subsequent coordinate transformation and pitch adjustment process.

[0065] The data acquisition module adopts a high-frequency continuous acquisition mode, with the acquisition frequency matching the response speed of the unit's pitch control. It can fully capture parameter changes under sudden operating conditions such as instantaneous gusts and wave impacts. After acquisition, all raw data are packaged in a unified data format and transmitted in real time to the downstream torque calculation module and attitude processing module through the internal bus, realizing the synchronous distribution of raw signals and ensuring the real-time performance of subsequent module calculations.

[0066] The torque calculation module receives the blade root bending moment, blade azimuth angle, and pitch angle data transmitted by the data acquisition module. Each blade of a floating wind turbine generates an independent blade root bending moment, which is a physical quantity in the local coordinate system of the blade. However, the overall load control and pitch strategy optimization of the unit need to be analyzed and calculated based on a unified fixed hub coordinate system. If the local bending moment data of the blade is used directly for control, the inconsistency of the coordinate system will cause calculation deviations, which will lead to inaccurate control commands. Therefore, a special coordinate transformation algorithm must be used to complete the coordinate system transformation of the load parameters. The torque calculation module undertakes this core task.

[0067] This module incorporates a mature Park coordinate transformation algorithm, which is widely used in load calculation scenarios in the wind power field. It has the advantages of fewer calculation steps, less computational load, high calculation accuracy, and short operation time, which meets the operational requirements of real-time control of the unit.

[0068] After receiving valid data transmitted from upstream, the module first extracts the blade root bending moment and the corresponding pitch angle data, and calculates the out-of-plane blade root bending moment component of the wind turbine through preset calculation logic. The out-of-plane bending moment of the wind turbine is the main cause of the yaw and pitch load fluctuation of the wind turbine, and is also the core intermediate parameter for subsequent evaluation of the overall torque of the wind turbine.

[0069] After obtaining the out-of-plane blade root bending moment component, the module combines the synchronously received real-time blade azimuth angle to completely transform the bending moment component in the local coordinate system of the blade to the unified fixed hub coordinate system of the entire unit.

[0070] After a complete coordinate transformation calculation, the torque calculation module finally calculates the yaw moment and pitch moment of the wind turbine in the fixed hub coordinate system. The yaw moment and pitch moment can comprehensively reflect the asymmetric aerodynamic and mechanical loads on the entire wind turbine, and are the basis for judging whether the unit has exceeded the load limit and whether pitch adjustment needs to be started.

[0071] After the calculation is completed, the module outputs the two types of result data, namely the wind turbine yaw moment and the wind turbine pitch moment, to the downstream index calculation module in real time, completing the calculation and transfer of load parameters. The module performs the calculation automatically throughout the process without manual intervention. It can continuously follow the blade rotation status and pitch angle changes to dynamically update the moment values, ensuring that the moment data is synchronized with the actual operating status of the unit at all times.

[0072] The attitude processing module is mainly responsible for the professional processing of the platform pitch angle data output by the data acquisition module. Its purpose is to eliminate data deviations caused by coordinate system differences, filter out low-frequency interference signals caused by the marine environment, and avoid control conflicts between this control system and the original main control system of the unit, so as to ensure the effectiveness and reliability of attitude signals.

[0073] Floating platforms generate low-frequency, large-amplitude pitch motions under the influence of ocean waves. The low-frequency angular components corresponding to these low-frequency motions are invalid interference signals. If the raw pitch angle data is directly used for load calculation and pitch control, it will seriously interfere with the control logic and reduce control accuracy. Therefore, preprocessing of the pitch angle signal is essential.

[0074] In the coordinate transformation process, the module first extracts the platform pitch angle and wind turbine yaw angle data transmitted by the data acquisition module, and combines the wind turbine yaw angle value to map the pitch angle signal, which was originally based on the platform coordinate system, to the fixed hub coordinate system.

[0075] This conversion operation places the platform attitude data, wind turbine operation data, and blade load data in the same coordinate system, completely eliminating the problem of inconsistent signal references caused by the mixing of multiple coordinate systems. It effectively avoids signal distortion and calculation errors caused by coordinate deviations, and finally obtains the platform pitch angle data after coordinate calibration and filtering.

[0076] After the coordinate transformation is completed, the module starts the high-pass filter program to filter the pitch angle signal. This system specifically selects the platform's pitch mode natural frequency as the cutoff frequency of the high-pass filter. This parameter is set in combination with the structural characteristics of the floating platform itself, and has extremely strong adaptability to working conditions.

[0077] Filtering based on this cutoff frequency can accurately filter out the low-frequency angular components generated by the low-frequency pitching motion of the platform, while retaining the medium- and high-frequency signals that can reflect the effective operating status of the unit, thus minimizing the low-frequency interference caused by the coupling effect of wind, waves, and current.

[0078] At the same time, this filtering strategy can process signals in layers, avoiding the problems of control coupling and mutual interference between this collaborative control system and the original main control system of the unit from the source of the signal, and ensuring that the two control systems operate independently and in an orderly manner.

[0079] After completing all the coordinate transformation and high-pass filtering processes, the attitude processing module outputs the filtered high-precision platform pitch angle data and transmits it to the index calculation module and pitch adjustment module.

[0080] The index calculation module, combining various effective parameters collected and processed at the front end, calculates the degree of exceedance of the unit's ultimate load threshold. This quantitatively assesses the current load operating status of the floating wind turbine, distinguishes between normal operating conditions and load exceeding limits, and provides a basis for judgment in subsequent pitch adjustment actions.

[0081] Traditional wind power control schemes mostly use a single parameter and a single threshold to judge the operating conditions, which cannot fully reflect the complex load state under wind-wave-current coupling. This can easily lead to problems such as false protection triggering or load exceeding limits without timely response. This module adopts a multi-dimensional index joint evaluation mode to fundamentally solve this deficiency.

[0082] The calculation parameters in this module cover all core load signals across the entire operating range of the wind turbine. Specifically, these include the calibrated rotor speed, the filtered platform pitch angle, blade root bending moment, rotor yaw moment, and rotor pitch moment output from the moment calculation module. These parameters correspond to the turbine's rotational state, platform motion state, local blade loads, and overall rotor yaw and pitch loads, respectively, complementing each other and comprehensively covering the main load sources of floating wind turbines. The module has pre-set safety thresholds for various parameters, which are calibrated and stored in advance based on the turbine model, design parameters, and marine operating conditions.

[0083] After receiving all input parameters, the module performs threshold comparisons for each of the following parameters: rotor speed, platform pitch angle, blade root bending moment, rotor yaw moment, and rotor pitch moment, and calculates the degree of limit load exceeding the threshold for each parameter.

[0084] Single-category indicators can intuitively reflect the degree to which the corresponding parameters deviate from the safe operating range. The larger the indicator value, the more serious the overload problem of that type, and the higher the risk of the unit facing the ultimate load. The five categories of over-threshold indicators together constitute the unit's comprehensive load assessment system, which can comprehensively identify various extreme working conditions, including load anomalies caused by extreme gusts, wind shear, wave resonance, and severe platform swaying.

[0085] After the index calculation module completes the calculation of all indices, it outputs the complete set of extreme load exceeding threshold indices to the downstream pitch control module, realizing the transmission of load assessment results to the control execution link. This module has simple operation logic, low computational load, and fast response speed, and can realize real-time assessment of load status, ensuring that the control system can detect load anomalies as soon as possible, and reserving sufficient response time for rapid pitch control.

[0086] The pitch control module, combined with various front-end operating parameters, completes the dynamic adjustment of different components of the pitch angle of the independent pitch mechanism. It is a key link in realizing the coordinated control of ultimate load and fatigue load. This module breaks the traditional single pitch angle adjustment mode and divides the pitch angle into three independent adjustment components: zero component pitch angle, yaw component pitch angle, and pitch component pitch angle. Different components correspond to different control objectives.

[0087] The module first performs a product operation on the various over-threshold indicators corresponding to the wind turbine speed, platform pitch angle, blade root bending moment, wind turbine yaw moment, and wind turbine pitch moment. Through this operation, the multi-dimensional and scattered single-category over-limit indicators are integrated into a unified comprehensive over-limit degree.

[0088] The overall over-limit degree is a quantitative representation of the abnormal load state of the unit as a whole. It can unify the two major control objectives of fatigue load suppression and ultimate load protection, and solve the drawbacks of traditional technologies where the two types of objectives are difficult to coordinate and can only be handled with fixed weights. The module adaptively adjusts the control gain of the independent pitch system based on the real-time value of the overall over-limit degree. The higher the load over-limit degree, the higher the control gain is, and the pitch adjustment force is enhanced accordingly. When the load is in the normal range, the control gain returns to the normal range to avoid over-adjustment affecting the unit's power generation efficiency.

[0089] During the adjustment of each component pitch angle, the zero-component pitch angle is adjusted in a closed loop based on the rotor speed and the filtered platform pitch angle output by the attitude processing module. Its main function is to suppress the periodic fatigue load under normal operation of the unit and achieve continuous control of fatigue damage. The yaw component pitch angle and the pitch component pitch angle are adjusted independently in a closed loop according to the rotor yaw moment and rotor pitch moment, respectively. They focus on suppressing the peak value of the ultimate load caused by the rotor asymmetric load. During the adjustment process, the adaptively corrected control gain is used simultaneously to ensure that the adjustment action is accurately matched to the current load condition.

[0090] The three pitch angle components can be adjusted independently without interfering with each other. This can not only stably reduce the accumulation of fatigue load under normal operating conditions, but also quickly suppress the impact of ultimate load under extreme operating conditions, achieving a smooth switch between fatigue load suppression and ultimate load protection. After the pitch adjustment module completes the dynamic adjustment of all pitch angle components, it transmits the adjusted zero-component, yaw component, and pitch component pitch angle data to the last-stage control output module.

[0091] The control output module integrates all adjusted pitch angle components and, in conjunction with the output signals of the unit's original main control system, generates the final control command and sends it to the actuator to complete the full-process control closed loop. The module receives the three types of adjusted pitch angle components transmitted by the pitch adjustment module and simultaneously reads the reference pitch angle output by the unit's main control system in real time.

[0092] The reference pitch angle is a conventional pitch angle command generated by the unit based on basic operating targets such as power generation and rated speed, ensuring the stable operation of the unit's basic power generation function. The module superimposes the three types of adjustment components—zero component pitch angle, yaw component pitch angle, and pitch component pitch angle—according to preset calculation rules, and then performs a fusion calculation with the reference pitch angle to finally generate the total pitch control quantity.

[0093] The total pitch control parameter integrates the basic operational requirements of the turbine, the requirements for fatigue load suppression, and the requirements for ultimate load protection, achieving an organic unity of multiple control objectives. After generating the total pitch control parameter, the module outputs the control command to the pitch actuator of the floating wind turbine in real time and without interruption through the turbine's industrial control bus. The pitch actuator adjusts the actual pitch angle of the blades according to the received command, changing the aerodynamic shape and aerodynamic load of the blades, thereby achieving the regulation of various loads on the turbine.

[0094] The entire system starts with raw data acquisition, goes through signal processing, load calculation, state assessment, and pitch adjustment, and finally outputs execution commands to form a complete closed-loop control link. In normal marine environments, the system focuses on suppressing periodic fatigue loads and mitigating structural fatigue damage. Under extreme conditions such as gusts and giant waves, the system responds quickly to overload conditions, strengthens ultimate load protection, and effectively avoids ultimate damage to mechanical components. The entire modular control system can be installed as an independent control unit on existing floating wind turbines, or it can be directly integrated into the main control system of the turbine during the design phase of a new turbine, providing flexible deployment options.

[0095] In a third aspect of the present invention, a computer product is provided, the computer product storing a computer program, which, when executed by a processor, implements the above-described method for coordinated control of ultimate and fatigue loads of a floating wind turbine.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading the present invention, they can still make various changes, modifications or equivalent substitutions to the specific implementation of the invention, but these changes, modifications or equivalent substitutions are all within the scope of protection of the pending claims of the invention.

Claims

1. A method for coordinated control of ultimate and fatigue loads of a floating wind turbine, characterized in that, include: Real-time acquisition of platform attitude, wind turbine operating parameters, blade root bending moment, azimuth angle and pitch angle data output by the unit's sensors; Based on the blade root bending moment, azimuth angle and pitch angle data, coordinate transformation is performed to obtain the wind turbine yaw moment and pitch moment in a fixed hub coordinate system. Based on the platform's attitude, coordinate transformation and high-pass filtering are performed on the pitch angle to filter out low-frequency components and avoid interference with the main control system. Using the aforementioned limit load exceeding threshold index, the zero component, yaw component, and pitch component pitch angle of the independent pitch mechanism are dynamically adjusted. The adjusted pitch angles of each component are superimposed on the reference pitch angle output by the main control unit, and the total pitch control quantity is output to the pitch actuator.

2. The method for coordinated control of ultimate and fatigue loads of floating wind turbine generators according to claim 1, characterized in that, The platform attitude is acquired by attitude sensors installed on the floating platform, including the platform pitch angle and the platform roll angle; The wind turbine operating parameters are collected by the unit's main control system and hub encoder, including wind turbine speed and wind turbine yaw angle; The blade root bending moment is collected by a blade root bending moment sensor installed at the root of each blade, including the blade root flapping bending moment and the blade root swinging bending moment.

3. The method for coordinated control of ultimate and fatigue loads of floating wind turbine generators according to claim 1, characterized in that, The coordinate transformation adopts the Park coordinate transformation, which specifically includes: calculating the out-of-plane blade root bending moment component based on the blade root bending moment and the pitch angle, and transforming the bending moment component to a fixed hub coordinate system in combination with the blade azimuth angle to obtain the wind turbine yaw moment and wind turbine pitch moment.

4. The method for coordinated control of ultimate and fatigue loads of floating wind turbine generators according to claim 1, characterized in that, Performing coordinate transformation on the pitch angle specifically includes: By combining the wind turbine yaw angle, the platform pitch angle is uniformly mapped to a fixed hub coordinate system to obtain the platform pitch angle before filtering.

5. The method for coordinated control of ultimate and fatigue loads of floating wind turbine generators according to claim 1, characterized in that, The high-pass filter uses the platform's pitch mode natural frequency as the cutoff frequency.

6. The method for coordinated control of ultimate and fatigue loads of floating wind turbine generators according to claim 1, characterized in that, The specific indicators of the degree to which the ultimate load exceeds the threshold include: The over-threshold indicators corresponding to wind turbine speed, platform pitch angle, blade root bending moment, wind turbine yaw moment, and wind turbine pitch moment.

7. The method for coordinated control of ultimate and fatigue loads of floating wind turbine generators according to claim 6, characterized in that, The over-threshold indicators corresponding to the wind turbine speed, platform pitch angle, blade root bending moment, wind turbine yaw moment, and wind turbine pitch moment are multiplied to obtain the comprehensive over-limit degree, and the independent pitch control gain is adaptively adjusted according to the comprehensive over-limit degree.

8. The method for coordinated control of ultimate and fatigue loads of floating wind turbine generators according to claim 1, characterized in that, The zero-component pitch angle is adjusted in a closed loop based on the wind turbine speed and the filtered platform pitch angle. The yaw component pitch angle and the pitch component pitch angle are respectively adjusted in a closed loop based on the wind turbine yaw moment and wind turbine pitch moment, and the control gain is adaptively corrected. The total pitch control value is generated by superimposing the reference pitch angle, the zero component pitch angle, the yaw component pitch angle, and the pitch component pitch angle, and is output to the pitch actuator.

9. A collaborative control system for ultimate and fatigue loads of a floating wind turbine, characterized in that, include: The data acquisition module is used to collect platform attitude, wind turbine operating parameters, blade root bending moment, azimuth angle and pitch angle data output by the unit's sensors in real time; The torque calculation module is used to perform coordinate transformation based on the blade root bending moment, azimuth angle and pitch angle data to obtain the wind turbine yaw moment and pitch moment in a fixed hub coordinate system. The attitude processing module is used to perform coordinate transformation and high-pass filtering on the pitch angle according to the platform attitude, filter out low-frequency components and avoid interference with the main control system. The index calculation module is used to calculate the corresponding ultimate load exceeding threshold index based on the wind turbine speed, the platform pitch angle, the blade root bending moment, the yaw moment and the pitch moment; The pitch adjustment module is used to dynamically adjust the zero component, yaw component, and pitch component pitch angle of the independent pitch mechanism using the limit load exceeding the threshold index. The control output module is used to superimpose the adjusted pitch angle components with the reference pitch angle output by the main control unit, and output the total pitch control quantity to the pitch actuator.

10. A computer product storing a computer program, wherein when the computer program is executed by a processor, it implements the method for coordinated control of ultimate and fatigue loads of a floating wind turbine as described in any one of claims 1 to 8.

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