Wind generating set blade icing pre-control method and system

Abstract

The invention provides a wind generating set blade icing pre-control method and system, and relates to the technical field of wind driven generator control, and the technical scheme is characterized in that operation parameters and environment data of a wind generating set in the blade heating and deicing process are obtained; based on the operation parameters and the environmental data, evaluating the re-freezing risk of melting ice water generated on the surface of the blade on the blade to obtain an evaluated re-freezing risk; and when the evaluated re-freezing risk meets a set triggering condition, executing a set variable-pitch action, and enabling the molten ice water to be removed from the blade by changing the force acting on the molten ice water through the set variable-pitch action. The wind generating set blade icing pre-control method and system provided by the invention have the advantages.

Description

Technical Field

[0001] The present application relates to the field of wind turbine control technology, and in particular to a method and system for pre-controlling ice coating on blades of a wind turbine generator set. Background Art

[0002] When wind turbines operate under harsh climatic conditions of low temperature and high humidity, ice is very likely to form on the surface of their blades. Ice on the blades will significantly change their original aerodynamic shape, resulting in a decrease in the lift coefficient and an increase in the drag coefficient, seriously affecting the effective capture of wind energy and reducing power generation efficiency. In addition, uneven ice coverage will destroy the mass balance of the blades, generating huge unbalanced loads during high-speed rotation, causing fatigue damage to key components such as blades, hubs, main shafts, gearboxes, and towers, and may even lead to catastrophic structural damage accidents. In order to ensure the safe and stable operation of wind turbines in freezing environments, they are usually equipped with a blade ice pre-control system.

[0003] Active heating is a common method used in existing blade ice pre-control technologies. Heating elements are installed inside or on the blade surface. When ice risk is detected or ice has already formed, heating is activated, raising the blade surface temperature above freezing, thereby preventing ice formation or melting existing ice. This method can restore blade aerodynamic performance to a certain extent.

[0004] However, using heating for ice pre-control or de-icing generates a large amount of meltwater. This meltwater, driven by gravity and the centrifugal force generated by the blade's rotation, flows along the blade surface toward the blade tip or trailing edge. Because wind turbine blades have complex three-dimensional geometries and are subject to varying airflow under varying operating conditions, the meltwater's flow path isn't always smooth. This is especially true in areas like the blade's trailing edge and wingtip, or where minor defects exist on the blade surface, where meltwater can easily become sluggish, accumulate, or even stagnate.

[0005] A further problem is that even if the main blade area is kept above freezing by heating, the temperature of certain areas may still be lower when the meltwater flows through or converges on them. For example, the sharp edge of the blade trailing edge, the complex curved surface area of the wingtip, or the end or weak link covered by the heating system. These areas may be colder, even below freezing, due to the strong cooling effect of local airflow or the rapid heat dissipation of the system. When meltwater from the warmer areas flows to these cold areas, it is very likely to refreeze, forming a new layer of ice, which is called secondary ice.

[0006] This secondary ice formed by the refreezing of melted ice and water often has an irregular shape and may form ice ridges or icicles, which has a more severe and sudden impact on the local aerodynamic shape of the blade. At the same time, the adhesion strength of the secondary ice may be different from that of the initial icing, and its distribution is local and uncertain. Existing icing pre-control systems usually mainly focus on the detection of initial icing and the overall heating strategy, lacking effective monitoring means for the dynamic behavior of the melted ice and water generated during the heating process, and not fully considering the risk of refreezing of the melted ice and water in specific areas. The system may stop working after completing the preset heating cycle, but at this time, the refreezing process in local areas may still be ongoing or new ice accumulations may have formed.

[0007] The secondary ice that fails to be removed in time will become a new icing core, accelerating the subsequent accumulation of icing and causing the icing problem in specific areas of the blade to persist or worsen. In addition, the irregular secondary ice may generate more complex and unpredictable unbalanced loads, posing a potential threat to the safe operation of the unit. Existing technologies lack effective and low-cost active intervention strategies for guiding, discharging the melted ice and water, and preventing local refreezing after heating de-icing.

[0008] In view of the above problems, existing technologies urgently need to be improved. Summary of the Invention

[0009] The purpose of this application is to provide a method and system for pre-controlling icing on the blades of a wind turbine generator, which has the advantages of reducing or avoiding the risk of refreezing of melted ice and water on the blade surface, improving the de-icing effect, and ensuring the safety of the unit.

[0010] In a first aspect, this application provides a method for pre-controlling icing on the blades of a wind turbine generator, and the technical solution is as follows: It includes: Obtain the operating parameters and environmental data of the wind turbine generator during the blade heating de-icing process; Based on the operating parameters and the environmental data, evaluate the risk of refreezing of the melted ice and water generated on the blade surface on the blade to obtain the evaluated refreezing risk; When the evaluated refreezing risk meets the set trigger condition, perform the set pitch action, and the set pitch action changes the force acting on the melted ice and water to prompt the melted ice and water to be removed from the blade.

[0011] Furthermore, in this application, the step of performing the set pitch action, where the set pitch action changes the force acting on the melted ice and water to prompt the melted ice and water to be removed from the blade includes: Estimate the spanwise distribution area of the melted ice and water on the blade surface; Obtain the real-time rotational azimuth angle of the blade; Based on the predicted spanwise distribution area of the melting ice water on the blade surface, determine a predetermined azimuth angle interval such that when the blade rotates and the predicted spanwise distribution area of the melting ice water is within the predetermined azimuth angle interval, the resultant force acting on the melting ice water causes it to be removed from the blade; When the real-time rotation azimuth angle of the obtained blade is within the predetermined azimuth angle interval, perform the set pitch action, and by changing the force acting on the melting ice water, prompt the melting ice water to be removed from the blade.

[0012] Further, in the present application, the step of determining a predetermined azimuth angle interval based on the predicted spanwise distribution area of the melting ice water on the blade surface such that when the blade rotates and the predicted spanwise distribution area of the melting ice water is within the predetermined azimuth angle interval, the resultant force acting on the melting ice water causes it to be removed from the blade includes: Obtain the geometric feature information of the blade; Obtain the fluid action information during the rotation of the blade; Based on the geometric feature information of the blade, the fluid action information during the rotation of the blade, and the predicted spanwise distribution area of the melting ice water on the blade surface, determine which force component or combination of force components acting on the predicted spanwise distribution area of the melting ice water helps to remove the melting ice water at different azimuth angles of the blade rotation, and obtain the force component or combination of force components that helps to remove the melting ice water and the corresponding rotation azimuth angle; Based on the force component or combination of force components that helps to remove the melting ice water, the corresponding rotation azimuth angle, and the predicted spanwise distribution area of the melting ice water on the blade surface, determine the predetermined azimuth angle interval.

[0013] Further, in the present application, the step of determining which force component or combination of force components acting on the predicted spanwise distribution area of the melting ice water helps to remove the melting ice water at different azimuth angles of the blade rotation based on the geometric feature information of the blade, the fluid action information during the rotation of the blade, and the predicted spanwise distribution area of the melting ice water on the blade surface, and obtaining the force component or combination of force components that helps to remove the melting ice water and the corresponding rotation azimuth angle includes: Obtain a set of parameters related to the predicted spanwise distribution area of the melting ice water on the blade surface, which can reflect the aggregation state or flow characteristics of the melting ice water; Based on the set of parameters, identify the physical form of the melting ice water in the predicted spanwise distribution area of the melting ice water on the blade surface; Based on the geometric feature information of the blade, the fluid action information during the rotation of the blade, the predicted spanwise distribution area of the melting ice water on the blade surface, and the identified physical form of the melting ice water, determine which force component or combination of force components acting on the predicted spanwise distribution area of the melting ice water at different azimuth angles during blade rotation contributes to the removal of the melting ice water, and obtain the force component or combination of force components that matches the removal characteristics of the identified physical form of the melting ice water and the corresponding rotation azimuth angle.

[0014] Further, in the present application, the step of obtaining a set of parameters related to the predicted spanwise distribution area of the melting ice water on the blade surface, which can reflect the aggregation state or flow characteristics of the melting ice water, includes: Obtain the operating parameters of the wind turbine; Obtain environmental data; Obtain the pre-stored correlation information on the formation and evolution law of the melting ice water on the blade surface; Based on the obtained operating parameters of the wind turbine, the obtained environmental data, and the obtained pre-stored correlation information on the formation and evolution law of the melting ice water on the blade surface, infer the predicted thickness, coverage area ratio, and flow velocity range of the melting ice water in the predicted spanwise distribution area of the melting ice water on the blade surface; Take the inferred predicted thickness, coverage area ratio, and flow velocity range as a set of parameters related to the predicted spanwise distribution area of the melting ice water on the blade surface, which can reflect the aggregation state or flow characteristics of the melting ice water.

[0015] Further, in the present application, the step of evaluating the re-freezing risk of the melting ice water generated on the blade surface based on the operating parameters and the environmental data to obtain the evaluated re-freezing risk includes: Estimate the amount of melting ice water formed on the blade surface based on the operating parameters and preset physical property parameters; Identify specific areas on the blade where the melting ice water is prone to retention or the surface temperature is prone to decrease due to geometric structure or airflow influence as key areas for risk assessment; Analyze the current surface temperature state of the key areas based on the operating parameters, the environmental data, and the characteristics of the identified key areas; Evaluate the re-freezing risk of the melting ice water generated on the blade surface in the key areas based on the operating parameters, the environmental data, and in combination with the estimated amount of melting ice water and the analyzed current surface temperature state of the key areas to obtain the evaluated re-freezing risk.

[0016] Further, in the present application, the method further includes: Obtain the estimated total ice melting water volume on the blade surface, the information on the stage of the current heating process, and the real-time rotational azimuth angle of the blade; Based on the obtained estimated total ice melting water volume on the blade surface, the information on the stage of the current heating process, the evaluated refreezing risk, and the real-time rotational azimuth angle of the blade obtained, determine whether the preset pitch-assist drainage trigger condition combination is satisfied; If it is determined that the pitch-assist drainage trigger condition combination is satisfied, then based on the obtained real-time rotational azimuth angle of the blade and the preset drainage efficiency adjustment logic, determine the amplitude, rate, and mode of the pitch action; Execute the determined pitch action.

[0017] Further, in the present application, the step of executing the determined pitch action includes: When executing the determined pitch action, monitor the operating parameters of the drive mechanism that drives the blade to pitch, and obtain the monitored drive mechanism operating parameters; Compare the monitored drive mechanism operating parameters or the characteristic quantities calculated based on the monitored drive mechanism operating parameters with the preset drive mechanism operating parameter benchmark when the blade performs the same type of pitch action in the state where the ice melting water has been removed, and obtain a comparison result; If the comparison result indicates that the ice melting water is not sufficiently thrown off, execute a supplementary pitch action or adjust the parameters of the subsequent pitch action to promote the removal of the ice melting water.

[0018] Further, in the present application, the step of executing the determined pitch action includes: Based on the parameters related to the blade heating process or the blade historical icing information, estimate the concentrated distribution area of the ice melting water in the blade span direction; Obtain the real-time rotational azimuth angle of the blade; According to the estimated concentrated distribution area of the ice melting water in the blade span direction and the variation characteristics of the force acting on the concentrated distribution area during the blade rotation process, determine at least one predetermined rotational azimuth angle interval. The selection of the predetermined rotational azimuth angle interval aims to utilize or enhance the removal force acting on the ice melting water when the determined pitch action is executed when the estimated concentrated distribution area of the ice melting water is in this interval; When the obtained real-time rotational azimuth angle of the blade enters the at least one predetermined rotational azimuth angle interval, execute the determined pitch action.

[0019] In a second aspect, the present application also proposes a pre-control system for icing of a wind turbine blade, and the system includes: An acquisition module, configured to acquire the operating parameters and environmental data of the wind turbine during the blade heating and de-icing process; An evaluation module, configured to evaluate the risk of re-freezing of the melted ice and water generated on the blade surface based on the operating parameters and the environmental data, and obtain the evaluated re-freezing risk; A control module, configured to control the wind turbine generator set to perform a set pitch-changing action when the evaluated re-freezing risk meets a set trigger condition, and the set pitch-changing action changes the force acting on the melted ice and water, so as to prompt the melted ice and water to be removed from the blade.

[0020] As can be seen from the above, a method and a system for pre-controlling icing on a wind turbine blade provided by the present application evaluate the re-freezing risk of melted ice and water and perform a pitch-changing action when the risk meets the condition, and use the pitch change to change the force acting on the melted ice and water, so as to prompt the melted ice and water to be removed, thereby reducing or avoiding re-freezing. It has the advantages of being able to effectively reduce or avoid the re-freezing risk of melted ice and water on the blade surface, improving the de-icing effect and ensuring the safety of the unit. Description of the Drawings

[0021] Figure 1 It is a schematic flow chart of a method for pre-controlling icing on a wind turbine blade provided by the present application.

[0022] Figure 2 It is a schematic structural diagram of a system for pre-controlling icing on a wind turbine blade provided by the present application.

[0023] In the figure: 210, an acquisition module; 220, an evaluation module; 230, a control module. Detailed Embodiments

[0024] The technical solutions in the present application will be clearly and completely described below with reference to the drawings in the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the present application described and illustrated in the drawings here can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the present application provided in the drawings below is not intended to limit the scope of the present application to be protected, but only represents the selected embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts belong to the scope of protection of the present application.

[0025] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of the present application, the terms "first", "second", etc. are only used for distinguishing descriptions, and cannot be understood as indicating or implying relative importance.

[0026] When the traditional existing icing pre - control system for wind turbine blades uses heating to pre - control or de - ice icing, there is a problem that the melted ice water stays and refreezes in the blade surface area. The blade geometry, the centrifugal force generated by rotation, and the influence of air flow cause obstacles in the flow path of the melted ice water, which is likely to accumulate in areas such as the trailing edge and wing tips. Even if the heating system keeps most areas above the freezing point, these areas may have lower temperatures due to local cooling effects or heating coverage limitations. When the melted ice water flows through or converges to these low - temperature areas, refreezing may occur, forming secondary ice. The secondary ice has differences in morphology and properties from the initial icing, may have adhesiveness, and the existing system lacks means to identify and handle it.

[0027] For example, assume a wind turbine is operating under the conditions of an ambient temperature of - 3°C and a wind speed of 10 m / s, and ice has formed on the blade surface. The control system activates the internal electrical heating system of the blade for de - icing. The heating melts the ice in the leading edge and middle areas of the blade, generating melted ice water. Under the action of gravity and centrifugal force, this melted ice water flows towards the wing tip and trailing edge. However, in the edge area of the blade trailing edge, due to the increased local heat dissipation caused by the accelerated air flow, even if the heating system is still working, the surface temperature of this area may remain close to or below 0°C. When the melted ice water converges to this area, the flow rate of part of the water slows down and begins to refreeze under the action of low temperature, forming ice ridges. At this time, the heating system may have entered the power - down stage or is about to stop. The system judges that the main icing has been removed, but the secondary ice on the blade trailing edge is still forming or has already formed. The secondary ice changes the aerodynamic shape of the blade trailing edge, may cause local air flow separation, increase resistance, and generate aerodynamic noise. At the same time, the ice ridges increase the imbalance of the blade mass and generate vibration loads during rotation.

[0028] If the above problems are not solved, the secondary ice formed by the refreezing of the melted ice water generated during the heating de - icing process of the wind turbine blade will affect the aerodynamic performance of the blade, resulting in a decrease in energy capture efficiency. The secondary ice may trigger or exacerbate the unbalanced vibration of the blade, cause fatigue damage to components such as the hub, main shaft, and gearbox, and shorten the equipment life. The shedding of the secondary ice may pose a threat to the surrounding environment and personnel safety. In addition, the remaining secondary ice that has not been removed may become the starting point for subsequent icing, accelerating the formation of a new round of icing, making the blade icing problem occur repeatedly, increasing the de - icing frequency and energy consumption. The existing pre - control system has insufficient perception and processing capabilities for local refreezing phenomena and cannot ensure that the blade returns to a safe operating state without significant icing after the de - icing operation is completed.

[0029] In response to this, referring to Figure 1 , this application proposes a method for pre - controlling icing on wind turbine blades, including: S110. Obtain the operating parameters and environmental data of the wind turbine during the blade heating de - icing process; S120. Based on the operating parameters and environmental data, evaluate the risk of re-freezing of the melted ice water generated on the blade surface on the blade, and obtain the evaluated re-freezing risk; S130. When the evaluated re-freezing risk meets the set trigger condition, perform the set pitch action. The set pitch action changes the force acting on the melted ice water to prompt the melted ice water to be removed from the blade.

[0030] Among them, the operating parameters refer to the data reflecting the working state of the wind turbine during the blade heating and de-icing stage, such as the pitch angle, the rotational speed of the wind turbine rotor, the working power of the heating system, etc. Its main purpose is to obtain the basic information required for risk assessment; The environmental data refers to the conditions of the external environment where the wind turbine is located, such as the environmental temperature, humidity, wind speed, etc. Its main purpose is to obtain the basic information required for risk assessment; Evaluating the re-freezing risk means using the obtained operating parameters and environmental data, combined with a preset model or logic, to predict the possibility of the melted ice water generated on the blade surface re-freezing in a specific area on the blade. Its purpose is to provide a decision-making basis for whether to take intervention measures subsequently; The set trigger condition refers to the timing preset in advance to determine that a pitch action needs to be taken when the evaluated re-freezing risk reaches a certain state or meets specific combined conditions. Its main purpose is to ensure that intervention measures are initiated in a timely manner when the risk is high; The set pitch action refers to one or more blade pitch angle adjustment sequences specifically designed to remove the melted ice water. It can be achieved by a rapid small-amplitude change in the pitch angle, such as a brief increase or decrease based on the current pitch angle. Its main purpose is to change the force acting on the melted ice water (such as centrifugal force, aerodynamic component) to prompt the melted ice water to move or detach from the blade surface.

[0031] The core innovation of this application lies in combining the re-freezing risk assessment based on operating parameters and environmental data with specific actions of the existing pitch system of the wind turbine, thereby realizing the active intervention of the re-freezing risk of melted ice water during the heating and de-icing process without relying on additional sensors on the blade surface, achieving the effect of effectively suppressing the formation of secondary ice.

[0032] The solution of this application takes the operating parameters and environmental data of the wind turbine under specific working conditions as input, and uses this data to evaluate the risk of refreezing of the meltwater on the blade surface. This evaluation process is based on the analysis and judgment of existing information, rather than directly measuring the state of the meltwater. Once the evaluation result shows that the refreezing risk reaches the predetermined trigger condition, the system will activate the pitch system of the wind turbine and control the blade to execute a preset pitch action sequence dedicated to removing the meltwater. This pitch action changes the attitude of the blade relative to the airflow or the rotation plane, instantaneously changing the resultant force acting on the meltwater on the blade surface, such as enhancing the centrifugal force or introducing an aerodynamic component conducive to drainage, thereby overcoming the adhesion of the meltwater and prompting it to move from the blade surface towards the tip or trailing edge and finally be removed. The whole process forms a closed loop: the risk assessment guides the intervention timing, the pitch action performs the intervention, physically removes the meltwater, and reduces the refreezing risk. It is precisely due to this active risk intervention mechanism based on indirect information that the solution can effectively address the problem of refreezing of meltwater.

[0033] In a specific implementation, the wind turbine operates in a low-temperature and high-humidity environment and starts blade heating de-icing. The control system continuously obtains the operating parameters of the unit (such as heating power, heating duration) and environmental data (such as environmental temperature, wind speed). Based on this data, the system evaluates the risk of refreezing of the meltwater on the blade surface in areas such as the trailing edge of the blade through a built-in algorithm. For example, the algorithm may comprehensively consider the input heating energy to estimate the amount of meltwater and combine the environmental temperature and wind speed to predict the surface temperature of the trailing edge of the blade. When the estimated amount of meltwater reaches a certain level and the predicted trailing edge temperature is close to the freezing point, the evaluated refreezing risk is determined to meet the set trigger condition. At this time, the control system issues an instruction to drive the blade to execute a set pitch action, such as quickly increasing the pitch angle by a small amount (e.g., 2 degrees) from the current operating angle when the blade rotates to a specific azimuth angle, maintaining it for a short time (e.g., 0.5 seconds) and then quickly restoring. This rapid change in the pitch angle generates an additional centrifugal force component and aerodynamic disturbance, throwing the meltwater formed at the trailing edge of the blade off the blade surface and preventing it from refreezing again.

[0034] In some of the above embodiments of this application, it is proposed to execute a set pitch action. Specifically, this execution of the set pitch action can be achieved by quickly changing the pitch angle of the blade, using the resulting additional centrifugal force, change in gravitational component, and aerodynamic disturbance to prompt the movement or throwing off of the meltwater. In this way, the capabilities of the unit itself can be utilized to assist in removing the meltwater. However, how to precisely execute this pitch action to ensure that the meltwater can be effectively removed from the blade surface, especially considering the uneven distribution of the meltwater and the complexity of blade rotation, remains a problem to be solved.

[0035] In this regard, the present application further proposes a step of performing a set pitch action, and the set pitch action promotes the removal of the melted ice water from the blade by changing the force acting on the melted ice water, including: Estimate the spanwise distribution area of the melted ice water on the blade surface; Obtain the real-time rotational azimuth angle of the blade; Based on the estimated spanwise distribution area of the melted ice water on the blade surface, determine a predetermined azimuth angle interval such that when the blade rotates and the estimated spanwise distribution area of the melted ice water is within the predetermined azimuth angle interval, the resultant force acting on the melted ice water causes it to be removed from the blade; When the obtained real-time rotational azimuth angle of the blade is within the predetermined azimuth angle interval, perform the set pitch action, and by changing the force acting on the melted ice water, promote the removal of the melted ice water from the blade.

[0036] Among them, estimating the spanwise distribution area of the melted ice water on the blade surface refers to determining the approximate position or concentrated area of the melted ice water in the blade length direction. It can be achieved by various methods such as inference based on the operating parameters of the heating system, detection based on blade surface sensors (such as humidity or temperature sensor arrays), or calculation based on the physical model of blade icing / melting. The purpose is to obtain the position information of the melted ice water and provide a basis for determining a favorable pitch execution timing subsequently; determining the predetermined azimuth angle interval refers to calculating or looking up a table to obtain a range of blade rotation angles according to the estimated position of the melted ice water. It can be achieved by methods such as looking up a table based on historical operating data and empirical rules. The purpose is to identify the range of blade rotation angles where the resultant force (including gravity, centrifugal force, aerodynamic force, and additional force generated by pitching) acting on the melted ice water at a specific spanwise position during blade rotation is most favorable for its removal from the blade surface.

[0037] The solution of the present application combines the position information of the melted ice water on the blade with the real-time rotational azimuth angle of the blade to intelligently select the execution timing of the pitch action. Specifically, first, the spanwise area where the melted ice water may accumulate is obtained through estimation means, which lays the foundation for subsequent analysis. Then, the system monitors the current rotational azimuth angle of the blade in real time. The key is that based on the estimated spanwise distribution area of the melted ice water, the system determines a predetermined azimuth angle interval. The selection of this interval is optimized such that when this area rotates to this angle range, the resultant force direction and magnitude of various forces (such as gravity component, centrifugal force component, and additional force generated by the pitch action) acting on the melted ice water are most favorable for overcoming the adhesion force of the melted ice water and promoting its detachment from the blade surface. Finally, when the real-time rotational azimuth angle of the blade enters this predetermined favorable interval, the system immediately triggers the set pitch action. This method avoids blindly or randomly performing the pitch, but precisely applies the pitch action when the melted ice water is at the blade position and rotational attitude where it is most easily removed.

[0038] In this way, the rotational movement of the blade itself and the physical effects generated by the pitch action are effectively combined, significantly enhancing the removal efficiency of meltwater. Especially for areas where meltwater is prone to retention and refreezing, this targeted intervention can more effectively remove meltwater, thus solving the problem of meltwater refreezing.

[0039] In some of the above embodiments of the present application, a set pitch action is proposed. By changing the force acting on the meltwater, the meltwater is urged to be removed from the blade. Among them, to achieve this purpose, a predetermined azimuth angle interval needs to be determined such that when the blade rotates and the estimated spanwise distribution area of the meltwater is within the predetermined azimuth angle interval, the resultant force acting on the meltwater causes it to be removed from the blade. However, in the process of its implementation, only the predetermined azimuth angle interval is determined, lacking a comprehensive consideration of the physical properties of the blade itself, the external actions during rotation, and the specific distribution state of the meltwater. This may lead to the determined interval not fully utilizing the most favorable mechanical conditions and affecting the removal effect of the meltwater. Therefore, how to comprehensively consider these factors to more accurately determine the predetermined azimuth angle interval so as to more effectively remove the meltwater is a technical problem to be solved.

[0040] In response to this, the present application further proposes that based on the estimated spanwise distribution area of the meltwater on the blade surface, the steps for determining the predetermined azimuth angle interval such that when the blade rotates and the estimated spanwise distribution area of the meltwater is within the predetermined azimuth angle interval, the resultant force acting on the meltwater causes it to be removed from the blade include: Obtain the geometric feature information of the blade; Obtain the fluid action information during the rotation of the blade; Based on the geometric feature information of the blade, the fluid action information during the rotation of the blade, and the estimated spanwise distribution area of the meltwater on the blade surface, determine which force component or combination of force components acting on the estimated spanwise distribution area of the meltwater is helpful for the removal of the meltwater at different azimuth angles of the blade rotation, and obtain the force component or combination of force components helpful for the removal of the meltwater and the corresponding rotation azimuth angles; Based on the force component or combination of force components helpful for the removal of the meltwater, the corresponding rotation azimuth angles, and the estimated spanwise distribution area of the meltwater on the blade surface, determine the predetermined azimuth angle interval.

[0041] Among them, obtaining the geometric characteristic information of the blade refers to collecting the inherent physical parameters of the blade, such as the chord length distribution, torsion angle distribution, airfoil data, etc. of the blade. This information is the basic data for analyzing the force exerted on the melted ice water on the blade surface; obtaining the fluid action information of the blade rotation process refers to collecting the relevant information generated by the interaction between the blade and the air during rotation, such as the airflow velocity and pressure distribution in a specific area of the blade surface. This information is used to analyze the aerodynamic force acting on the melted ice water; judging which force component or combination of force components acting on the estimated spanwise distribution area of the melted ice water at different azimuth angles of blade rotation is conducive to the removal of the melted ice water, and obtaining the force component or combination of force components that is conducive to the removal of the melted ice water and the corresponding rotation azimuth angle is based on the geometry of the blade. The method comprises the following steps: analyzing the size and direction of various forces (such as gravity component, centrifugal force, aerodynamic force, etc.) acting on the melted ice water in a specific spanwise distribution area when the blade rotates at various azimuth angles from 0 to 360 degrees, and identifying which single force component or combination of multiple force components can produce the effect of causing the melted ice water to separate from the blade surface, thereby obtaining which favorable force effects exist at which rotation azimuth angles; determining the predetermined azimuth angle interval means using the favorable mechanical conditions and the azimuth angles at which they occur obtained in the aforementioned judgment step, and combining them with the estimated spanwise distribution area of the melted ice water on the blade surface, to specifically define the optimal time window for executing the pitch change action.

[0042] The solution of this application obtains information about the geometric characteristics of the blade and the fluid interaction during blade rotation, and combines this information with the estimated spanwise distribution of the meltwater on the blade surface to perform a physical analysis of the forces acting on the meltwater at different rotational angles. This allows the determination of the specific rotational angles at which the force component or combination of force components acting on the meltwater is most conducive to its removal from the blade surface.

[0043] Furthermore, based on these analysis results, one or more predetermined azimuth angle intervals can be precisely determined. When the blades rotate to these predetermined azimuth angle intervals, pitching operations are performed, effectively utilizing or enhancing the forces acting on the meltwater, thereby promoting its removal from the blades. This method, based on physical analysis and conditional judgment, provides a scientific basis for determining the optimal timing for pitching to assist in water removal. This allows pitching operations to more effectively utilize natural or aerodynamic forces to remove meltwater, improving the efficiency and thoroughness of meltwater removal.

[0044] In some preferred embodiments, the following may be implemented: First, obtain the geometric feature information of the blade. For example, read the airfoil data of the blade, the chord length, and the distribution curves of the twist angle along the span from the blade design database stored in the wind turbine control system. Next, obtain the fluid action information during the rotation of the blade. This can be achieved by performing pre-calculated computational fluid dynamics (CFD) simulations to obtain the surface pressure distribution and the airflow velocity field of the blade at different rotational speeds and pitch angles, and store this data as a lookup table for querying according to the real-time operating state during operation.

[0045] Meanwhile, estimate the spanwise distribution area of the melting ice water on the blade surface according to the previous steps. For example, estimate that the melting ice water is mainly concentrated in a certain spanwise range at the trailing edge of the blade. Then, based on the obtained blade geometric feature information, fluid action information, and the estimated spanwise distribution area of the melting ice water, conduct a force analysis. For example, for the estimated melting ice water area, calculate the magnitudes and directions of the gravitational component, centrifugal component, and aerodynamic force (calculated from the fluid action information) acting on the melting ice water in this area at different azimuth angles during one rotation (0 - 360 degrees) of the blade. Determine at which azimuth angles the resultant force of these forces or its component perpendicular to the blade surface points outside the blade, or which force components (such as the spanwise component of the centrifugal force) contribute to the flow of the melting ice water along the blade tip direction.

[0046] Thus, obtain the force component or combination of force components (such as the cooperative action of gravity and centrifugal force) that helps remove the melting ice water and the corresponding rotational azimuth angle (such as a certain angular range when the blade is in the lower region). Finally, based on these analysis results, determine a predetermined azimuth angle interval. For example, select those continuously azimuth angle ranges with the most favorable forces as the predetermined interval.

[0047] In some of the above embodiments of the present application, a solution is proposed to determine a predetermined azimuth angle interval based on the estimated spanwise distribution area of the melting ice water on the blade surface, such that when the blade rotates and the estimated spanwise distribution area of the melting ice water is within the predetermined azimuth angle interval, the resultant force acting on the melting ice water causes it to be removed from the blade. In this way, the rotational position of the blade that is favorable for removing the melting ice water can be determined according to the characteristics of the blade and the fluid and the distribution of the melting ice water. However, in the process of its implementation, it is not enough to only consider the blade geometric feature information, the fluid action information during the blade rotation, and the estimated spanwise distribution area of the melting ice water on the blade surface, because the physical form of the melting ice water on the blade surface will directly affect its force characteristics and the difficulty of removal. For melting ice water with different physical forms, under the action of the same force, the removal effect may be different. Therefore, if the physical form of the melting ice water is ignored, it may lead to inaccurate judgment of the force component or combination of force components required to remove the melting ice water, thereby affecting the effectiveness of the pitch control action.

[0048] In this regard, the present application further provides steps for determining which force component or combination of force components acting on the predicted spanwise distribution region of the melted ice and water is helpful for removing the melted ice and water at different azimuth angles of the blade rotation, and obtaining the force component or combination of force components helpful for removing the melted ice and water and the corresponding rotation azimuth angle, including: Obtain a set of parameters related to the predicted spanwise distribution region of the melted ice and water on the blade surface, which can reflect the aggregation state or flow characteristics of the melted ice and water; Based on the set of parameters, identify the physical form of the melted ice and water in the predicted spanwise distribution region of the melted ice and water on the blade surface; Based on the geometric feature information of the blade, the fluid action information during the blade rotation process, the predicted spanwise distribution region of the melted ice and water on the blade surface, and the identified physical form of the melted ice and water, determine which force component or combination of force components acting on the predicted spanwise distribution region of the melted ice and water is helpful for removing the melted ice and water at different azimuth angles of the blade rotation, and obtain the force component or combination of force components that matches the removal characteristics of the identified physical form of the melted ice and water and the corresponding rotation azimuth angle.

[0049] Among them, the set of parameters that can reflect the aggregation state or flow characteristics of the melted ice and water refers to a set of data or indicators used to describe the quantity, range, morphological characteristics, or motion state of the melted ice and water in the distribution region on the blade surface. It can be realized by parameters such as the predicted thickness of the melted ice and water, the coverage area ratio, and the flow velocity range obtained by sensor measurement, based on look-up tables, etc. Its purpose is to provide input information for subsequent identification of the specific physical form of the melted ice and water; Among them, identifying the physical form of the melted ice and water in the predicted spanwise distribution region of the melted ice and water on the blade surface means determining the specific existing form of the melted ice and water in this region according to the obtained set of parameters. It can be realized by mapping the set of parameters to predefined different physical form categories (such as discrete water droplets, continuous water films, converging runoff, etc.) based on preset rules, look-up tables, or classification algorithms. Its purpose is to identify the actual morphological characteristics of the melted ice and water and provide a basis for selecting targeted removal strategies; Among them, the force component or combination of force components that matches the removal characteristics of the identified physical form of the melted ice and water and the corresponding rotation azimuth angle refers to determining the force that is most easily removed in this form (such as centrifugal force, gravity component, aerodynamic force, or their combination) according to the identified physical form of the melted ice and water, and the specific azimuth angle range where the blade rotates to generate or enhance these forces. It can be realized by using physical models or empirical rules established according to the response characteristics of various forces to different physical forms, calculating or looking up various force components acting on the melted ice and water in this form at different azimuth angles, and selecting the combination of force components that can generate sufficient removal effect and the corresponding azimuth angle. Its purpose is to ensure that the selected removal force action and blade position can effectively promote the removal of the melted ice and water in the current form from the blade surface.

[0050] The solution of this application obtains a set of parameters that can reflect the aggregation state or flow characteristics of meltwater, and identifies the specific physical form of the meltwater based on these parameters. It is precisely because the identified physical form of the meltwater is used as an important basis for judging the force components or combinations of force components that contribute to the removal of meltwater and the corresponding rotation azimuth angle that the judgment of favorable removal conditions can more accurately match the removal requirements of different meltwater forms.

[0051] This is because meltwater in different physical forms has different sensitivities to forces such as centrifugal force, aerodynamic force, and gravity components, as well as different force thresholds required for removal. For example, film-like meltwater may be more easily affected by aerodynamic force and centrifugal force, while discrete water droplets may be more sensitive to gravity components and inertial forces generated by rapid pitch changes.

[0052] By identifying the specific form, the solution can targetedly select or combine the most effective force components and determine the azimuth angle at which the blade rotates to maximize these forces, thereby improving the accuracy of the judgment and the effectiveness of the subsequent pitch-assisted drainage strategy. This way of integrating the physical form characteristics of meltwater into the decision-making process is an improvement over the existing judgment logic, making the removal strategy more targeted.

[0053] In some specific implementation manners, a set of parameters that can reflect the aggregation state or flow characteristics of meltwater related to the predicted spanwise distribution area of meltwater on the blade surface is obtained. Specifically, it can be by obtaining the operating parameters of the wind turbine generator, environmental data, and the associated information of the formation and evolution law of meltwater on the blade surface stored in advance, and inferring the predicted thickness, coverage area ratio, and flow velocity range of meltwater in the predicted spanwise distribution area of meltwater on the blade surface based on this information, and using these inferred parameters as the set of parameters.

[0054] Based on the set of parameters, for example, according to the combination of the predicted thickness, coverage area ratio, and flow velocity range, identify the physical form of the meltwater in the predicted spanwise distribution area of meltwater on the blade surface, such as judging whether it presents as a film-like, droplet-like, or converging runoff-like form. Based on the geometric feature information of the blade, the fluid action information during the blade rotation process, the predicted spanwise distribution area of meltwater on the blade surface, and the identified physical form of the meltwater, for example, if the meltwater is identified as film-like, the system will focus on analyzing at which azimuth angles the centrifugal force or aerodynamic force has the strongest removal effect on the film; if it is identified as droplet-like, it may pay more attention to at which azimuth angles the gravity component or the inertial force generated by rapid pitch changes is more effective in flinging off the water droplets.

[0055] Through such analysis and judgment, obtain the force components or combinations of force components that match the removal characteristics of the identified physical form of the meltwater and the corresponding rotation azimuth angle.

[0056] In some of the above - mentioned embodiments of the present application, a set of parameters related to the predicted span - wise distribution region of the melted ice - water on the blade surface, which can reflect the aggregation state or flow characteristics of the melted ice - water, is proposed. Specifically, it can be through a simple empirical model. For example, according to the total heating duration and average power of the blade heating system, combined with the ambient temperature, the total amount of melted ice - water generated on the blade surface is estimated, and this total amount is used as a parameter. In this way, a preliminary understanding of the overall scale of the melted ice - water can be obtained. However, in the process of its implementation, only a set of parameters related to the predicted span - wise distribution region of the melted ice - water on the blade surface, which can reflect the aggregation state or flow characteristics of the melted ice - water, is obtained, lacking an assessment of the detailed state (such as local thickness, coverage range, and flow velocity) of the melted ice - water in a specific region. This may lead to inaccurate identification of the physical form of the melted ice - water, unable to fully reflect the real state of the melted ice - water on the blade surface, especially in the areas prone to refreezing, making the subsequent pitch - changing action may not be able to specifically solve the local refreezing problem and affecting the de - icing effect.

[0057] In response to this, the steps for the present application to further obtain a set of parameters related to the predicted span - wise distribution region of the melted ice - water on the blade surface, which can reflect the aggregation state or flow characteristics of the melted ice - water, include: Obtain the operating parameters of the wind turbine generator set; Obtain environmental data; Obtain the pre - stored correlation information on the formation and evolution law of the melted ice - water on the blade surface; Based on the obtained operating parameters of the wind turbine generator set, the obtained environmental data, and the obtained pre - stored correlation information on the formation and evolution law of the melted ice - water on the blade surface, infer the predicted thickness, coverage area ratio, and flow velocity range of the melted ice - water within the predicted span - wise distribution region of the melted ice - water on the blade surface; Take the inferred predicted thickness, coverage area ratio, and flow velocity range as a set of parameters related to the predicted span - wise distribution region of the melted ice - water on the blade surface, which can reflect the aggregation state or flow characteristics of the melted ice - water.

[0058] Among them, the pre - stored correlation information on the formation and evolution law of the melted ice - water on the blade surface refers to the prior knowledge or empirical model that has established the regular relationships such as the thickness, coverage situation, and flow trend that the melted ice - water may present on the blade surface under different combinations of operating parameters and environmental data. It can be implemented by a rule set, look - up table, or machine - learning model stored in a database, and its purpose is to provide logical rules or reference benchmarks for inference based on the current data.

[0059] Among them, the estimated thickness refers to the estimated value of the average or maximum water layer thickness of the estimated melted ice water within a specific spanwise distribution area on the blade surface. It can be achieved by means of calculating based on the estimated melted ice water volume and the distribution model, and its purpose is to characterize the aggregation degree of the melted ice water.

[0060] Among them, the coverage area ratio refers to the ratio of the area covered by the estimated melted ice water within a specific spanwise distribution area on the blade surface to the total area of this area. It can be achieved by means of calculating based on the estimated melted ice water volume and the surface spreading model, and its purpose is to characterize the distribution breadth of the melted ice water.

[0061] Among them, the flow velocity range refers to the estimated interval of the possible flow velocity of the estimated melted ice water within a specific spanwise distribution area on the blade surface. It can be achieved by means of analyzing the forces acting on the blade (gravity, centrifugal force, aerodynamic force) and calculating based on the fluid dynamics model, and its purpose is to characterize the flow characteristics of the melted ice water.

[0062] Among them, the parameter set refers to the data set formed by combining the inferred estimated thickness, coverage area ratio and flow velocity range. It can be achieved by using a vector or structure containing three numerical values, and its purpose is to provide effective and quantitative input for the subsequent identification of the physical form of the melted ice water.

[0063] The solution of this application obtains the operating parameters of the wind turbine, environmental data, and the associated information of the pre-stored formation and evolution law of the melted ice water on the blade surface, and infers the estimated thickness, coverage area ratio and flow velocity range of the melted ice water within the spanwise distribution area on the blade surface based on this information. Finally, these inferred parameters are used as a parameter set reflecting the aggregation state or flow characteristics of the melted ice water.

[0064] This method utilizes the existing operating data of the wind turbine itself and external environmental information, combines with the pre-established model of the behavior law of the melted ice water, and realizes the indirect and non-invasive evaluation of the key physical characteristics of the melted ice water on the blade surface. By inferring the three specific parameters of the estimated thickness, coverage area ratio and flow velocity range, this solution can more precisely depict the state of the melted ice water in a specific area, rather than just a total water volume or a simple judgment of existence or non-existence. These more descriptive parameter sets provide richer and more accurate basis for the subsequent identification of the physical form of the melted ice water (for example, whether it is a thin water film, local water accumulation or a flowing droplet flow).

[0065] Compared with the solutions that only rely on the total water volume or simple judgment, the parameter set provided by this solution can more effectively support the differentiation of the physical forms of melting ice and water, so that the pitch actions taken based on the identification results can more accurately target the removal characteristics of different forms of melting ice and water, improving the efficiency and thoroughness of melting ice and water removal, especially when dealing with the melting ice and water in areas prone to retention and refreezing. This method of inferring key parameters and constructing a parameter set through indirect information avoids the cost and maintenance burden of installing additional sensors on the blade surface, provides a practical and economical way to obtain parameters, and lays a solid foundation for subsequent identification of the physical forms of melting ice and water and pitch-assisted drainage strategies.

[0066] In some preferred embodiments, specifically, the current power of the blade heating system, the cumulative heating duration, the current pitch angle of the blade, and the wind turbine speed can be obtained as the operating parameters of the wind turbine generator. At the same time, the system obtains the environmental temperature, humidity, and wind speed from a weather station or nacelle sensors as environmental data. In addition, the system loads pre-stored association information, such as a look-up table or model established based on historical data and simulation, which describes the possible thickness, coverage ratio, and flow velocity range of melting ice and water in a specific spanwise region at the trailing edge of the blade under different heating states, environmental conditions, and blade postures. Based on the obtained operating parameters, environmental data, and pre-stored association information, the system makes inferences. For example, if the heating power is high, the cumulative duration is long, the environmental temperature is close to the freezing point, and the wind speed is high, and the trailing edge region of the blade is identified as an area prone to water accumulation, the system may infer that the estimated thickness in this region is within a certain millimeter-level range, the coverage area ratio reaches a certain percentage, and the flow velocity range is within a certain meter-per-second interval due to the action of air flow and gravity. The system packs the inferred numerical values of these estimated thickness, coverage area ratio, and flow velocity range into a parameter set for use in subsequent steps.

[0067] In some of the above embodiments of the present application, a method is proposed to evaluate the refreezing risk of the melting ice and water generated on the blade surface based on the operating parameters and environmental data, and obtain the evaluated refreezing risk. This evaluated refreezing risk can specifically be by monitoring the total heating energy of the blade heating system and combining it with the environmental temperature. For example, when the total heating energy reaches a preset threshold and the environmental temperature is below the freezing point, it is determined that there is a refreezing risk. In this way, a preliminary judgment of the refreezing risk can be made. However, in its implementation process, relying only on the overall operating parameters and environmental data, lacking the quantitative estimation of the amount of melting ice and water and the consideration of the local characteristics of the blade surface, may not accurately and effectively evaluate the refreezing risk, especially in the case of not relying on a large number of additional sensors, resulting in inaccurate evaluation results and being difficult to effectively guide subsequent pitch actions, thus affecting the overall de-icing effect.

[0068] In this regard, the present application further proposes that the steps of assessing the risk of refreezing of ice melt water generated on the blade surface include: Estimate the amount of ice melt water formed on the blade surface based on operating parameters and preset physical characteristic parameters; Identify specific areas on the blade where meltwater is likely to be retained or the surface temperature is likely to drop due to geometric structure or airflow, as key areas for risk assessment; Analyze the current surface temperature status of critical areas based on operating parameters, environmental data, and the characteristics of identified critical areas; Based on operating parameters, environmental data, and combined with the estimated amount of meltwater and the current surface temperature state of the analyzed key areas, the refreezing risk of the meltwater generated on the blade surface in the key areas is evaluated to obtain the assessed refreezing risk.

[0069] Among them, the preset physical characteristic parameters refer to the parameters related to the physical properties of ice and water and the energy conversion process that need to be used when estimating the amount of melt water. They may include the latent heat of melting of ice, the specific heat capacity of water, the thermal conductivity of the blade material, the energy conversion efficiency of the heating system, etc. These parameters can be determined and stored through experiments, simulations or reference to materials during the system design phase.

[0070] Among them, the specific areas on the blade where melted ice water is easily retained or the surface temperature is easily lowered due to the geometric structure or airflow refers to the areas on the blade surface where melted ice water is easily gathered, flows slowly or even stagnated due to its own shape characteristics (such as grooves, edges, complex curved surfaces), or the areas where local heat exchange is enhanced due to the airflow effect generated by the rotation of the blade and the surface temperature is more likely to drop below the freezing point. It may include the trailing edge of the blade, the wingtip part, specific chord-wise positions of certain span-wise positions, etc.

[0071] Among them, the key areas for risk assessment refer to the specific areas identified above that are prone to retaining meltwater or prone to temperature drop, which are the focus of attention and analysis when assessing the risk of meltwater refreezing.

[0072] Among them, the characteristics of the identified key areas refer to the physical properties or state information related to the above-identified key areas, which may include the geometric shape, material properties, orientation relative to the airflow, coverage of the heating system, etc. of the key areas. These characteristics can affect the flow and thermodynamic state of the meltwater in the area.

[0073] Among them, the current surface temperature state of the key area refers to the surface temperature or temperature change trend of the above-identified key area at the current moment, which can be obtained by calculating, estimating or inferring by combining operating parameters, environmental data and characteristics of the key area.

[0074] Among them, the estimated ice melting water volume refers to the total amount of melted ice water that has currently formed on the blade surface or the ice melting water volume in a local area, which is calculated or inferred by analyzing the operating parameters of the blade heating system and combining with preset physical property parameters.

[0075] The solution of this application realizes the refined judgment of the risk by refining the evaluation process of the refreezing risk into multiple interrelated steps.

[0076] First, by analyzing the operating parameters of the blade heating process and combining with preset physical property parameters, the ice melting water volume generated on the blade surface can be quantitatively estimated, which provides a quantitative basis for potential icing substances for risk assessment.

[0077] Next, the solution identifies specific areas on the blade that are naturally at high risk due to geometric configuration or airflow influence, focuses the evaluation on these key areas, and improves the pertinence of the evaluation. On this basis, by combining the operating parameters, environmental data, and the characteristics of these key areas themselves, the current surface temperature state of these high-risk areas is analyzed, so as to obtain direct information on whether the melted ice water has the refreezing temperature condition.

[0078] Finally, information such as the estimated ice melting water volume, the temperature state of the key areas, the operating parameters, and the environmental data are integrated to evaluate the possibility of refreezing of the melted ice water in these key areas. This step-by-step, focused, and quantitative evaluation method can capture the key factors for local refreezing more accurately than the method of making a rough judgment based only on overall parameters, thus obtaining a more accurate refreezing risk assessment result. This accurate assessment result can effectively guide the subsequent decision on whether to trigger the pitch action, and improves the accuracy and effectiveness of the entire pre-control method.

[0079] In some preferred embodiments, the present application is specifically implemented as follows: During the ice melting and deicing process of the wind turbine blade, the control system executes the step of evaluating the refreezing risk of the melted ice water on the blade surface. Specifically, the system first estimates the ice melting water volume formed on the blade surface based on the operating parameters of the blade heating system, such as recording the cumulative heating duration and average heating power of each heating area, and combining with preset physical property parameters, such as the latent heat of fusion of ice and the empirical efficiency coefficient.

[0080] For example, if the main heating area at the leading edge of the blade is heated for 30 minutes with an average power of 2 kW, and the auxiliary heating area at the trailing edge is heated for 20 minutes with an average power of 0.8 kW, using the latent heat of fusion of ice of 334 kJ / kg and an empirical coefficient of 0.7, the total ice melting water volume can be estimated to be approximately 9.7 kg.

[0081] Meanwhile, the system identifies specific areas on the blade where the melt water is prone to retention or the surface temperature is prone to decrease due to geometric structure or airflow effects, such as the trailing edge and tip sections of the blade, and takes these areas as key areas for risk assessment. Then, based on the current operating parameters (such as blade rotational speed, pitch angle), environmental data (such as environmental temperature -5°C, wind speed 12 m / s), and the characteristics of the identified key areas (such as the geometry and material of the trailing edge), the system analyzes the current surface temperature state of these key areas, for example, estimating the surface temperature of the trailing edge area through a simplified heat balance model or a look-up table method.

[0082] Finally, based on the current operating parameters, environmental data, combined with the estimated melt water volume (such as 9.7 kg) and the analyzed current surface temperature state of the key areas (such as the trailing edge area temperature approaching the freezing point), the system comprehensively evaluates the re-freezing risk of the melt water generated on the blade surface in the key areas. For example, if the estimated water volume is large and the temperature of the key area is close to or below the freezing point, the re-freezing risk is evaluated as high.

[0083] In some of the above embodiments of the present application, a method for evaluating the re-freezing risk of the melt water generated on the blade surface based on operating parameters and environmental data is proposed to obtain the evaluated re-freezing risk for identifying the risk where the melt water may re-freeze. However, relying solely on the evaluation result of the re-freezing risk may not be sufficient to guide an effective de-icing strategy. For example, in the case of a small melt water volume or a specific stage of the heating process, even if there is a certain re-freezing risk, it may not be necessary to immediately perform a pitch change operation, or it may be necessary to optimize the pitch change operation according to the real-time rotational azimuth angle of the blade to achieve a better drainage effect. Therefore, how to comprehensively consider factors such as the melt water volume, heating stage, re-freezing risk, and blade azimuth angle to more accurately trigger and adjust the pitch change operation is the problem to be solved by this solution.

[0084] In response to this, the present application further proposes a method including: Obtain the estimated total melt water volume on the blade surface, the information of the current stage of the heating process, and the real-time rotational azimuth angle of the blade; Based on the obtained estimated total melt water volume on the blade surface, the information of the current stage of the heating process, the evaluated re-freezing risk, and the obtained real-time rotational azimuth angle of the blade, determine whether the preset combination of pitch change auxiliary drainage trigger conditions is satisfied; If it is determined that the pitch change auxiliary drainage trigger condition combination is satisfied, then based on the obtained real-time rotational azimuth angle of the blade and the preset drainage efficiency adjustment logic, determine the amplitude, rate, and mode of the pitch change operation; Execute the determined pitch change operation.

[0085] Among them, the estimated total ice melting water volume on the blade surface refers to the total information of the ice melting water on the blade surface obtained through calculation or inference, which can be realized by estimating based on the operating parameters of the heating system. Its purpose is to provide a quantitative basis for judging whether there is enough ice melting water on the current blade that can be effectively removed through the pitch action; Among them, the information on the stage of the current heating process refers to the information reflecting the progress status of the blade heating and deicing process, which can be represented in the form of the elapsed heating time, the estimated remaining heating time, or the heating power change curve, etc. Its purpose is to evaluate the sufficiency of the ice melting process and ensure that the pitch drainage operation is carried out in a favorable time window; Among them, the preset combination of pitch-assisted drainage trigger conditions refers to a set of logical judgment rules composed of multiple specific conditions set in advance, which can be realized by logical gate circuits or software judgment statements. Its purpose is to achieve precise control of the starting timing of pitch-assisted drainage through comprehensive judgment of multiple factors; Among them, the preset drainage efficiency adjustment logic refers to the established rules or calculation methods aimed at maximizing the removal effect of ice melting water, which can be realized by look-up table methods, calculations based on physical models, or machine learning models. Its purpose is to output the optimal pitch control parameters according to the input real-time working condition information.

[0086] The solution of this application further obtains the total estimated ice melting water volume on the blade surface, the information on the stage of the current heating process, and the real-time rotation azimuth angle of the blade on the basis of evaluating the re-freezing risk. It is precisely because of obtaining these multi-dimensional real-time working condition inputs that the subsequent drainage decision-making and parameter configuration have a more comprehensive information basis.

[0087] Based on the obtained estimated total ice melting water volume on the blade surface, the information on the stage of the current heating process, the evaluated re-freezing risk, and the obtained real-time rotation azimuth angle of the blade, the system comprehensively judges whether the preset combination of pitch-assisted drainage trigger conditions is met. It is precisely because of this multi-factor comprehensive judgment mechanism that the pitch-assisted drainage action can be accurately triggered at the critical moment when the ice melting water volume is appropriate, the heating stage is suitable, the re-freezing risk exists, and the blade attitude is conducive to drainage, thus avoiding ineffective or untimely pitch operations.

[0088] On this basis, if it is judged that the trigger condition is met, then further based on the obtained real-time rotation azimuth angle of the blade and the preset drainage efficiency adjustment logic, the specific amplitude, rate, and mode of the pitch action are dynamically determined. It is precisely because the pitch parameters are dynamically adjusted according to the real-time azimuth angle and the preset logic that the pitch action can utilize or enhance the removal force acting on the ice melting water under a specific blade attitude, in order to generate the most favorable mechanical effect for ice melting water removal under specific conditions, thereby maximizing the drainage effect.

[0089] Finally, the determined pitch action is executed to convert the entire pre-control strategy into actual physical intervention. By changing the force acting on the ice-melting water, it is promoted to detach from the blade surface, achieving the purpose of suppressing or removing the formation of secondary ice. This strategy of combining multi-dimensional real-time information with re-freezing risk assessment and dynamically optimizing pitch parameters realizes a more refined and scenario-adaptive control compared to the method of only relying on a single risk threshold to trigger fixed actions, improving the effectiveness of ice-melting water removal.

[0090] In some preferred embodiments, the present application is specifically implemented as follows: Suppose during the blade heating and de-icing process, the system has evaluated that the re-freezing risk is high based on operating parameters and environmental data. At this time, the system obtains the estimated total ice-melting water volume on the blade surface, for example, the estimated value is 9.7 kg. At the same time, the system obtains the stage information of the current heating process, for example, the heating has lasted 70% of the total planned time. The system also obtains the real-time rotational azimuth angle of the blade, for example, it is currently at the 3 o'clock azimuth. Based on the obtained 9.7 kg ice-melting water volume, 70% heating stage information, high re-freezing risk assessment result, and the real-time rotational azimuth angle of 3 o'clock, the system determines whether the preset combination of pitch-assisted drainage trigger conditions is met.

[0091] The combined conditions can be set as follows: the ice-melting water volume is greater than 5 kg, and the heating stage is between 50% and 90% of the total duration, and the re-freezing risk is medium or high, and the blade azimuth angle is within a predetermined interval favorable for drainage, such as the 6 o'clock to 8 o'clock azimuth. Suppose the current azimuth angle is 3 o'clock and does not meet the azimuth angle condition. The system can wait for the blade to rotate to the predetermined azimuth angle interval. When the blade rotates to the 7 o'clock azimuth, the trigger condition combination is met. At this time, based on the obtained real-time rotational azimuth angle of the blade at 7 o'clock and the preset drainage efficiency adjustment logic, the system determines the amplitude, rate, and mode of the pitch action. The preset logic can determine that the gravity component is favorable for drainage according to the 7 o'clock azimuth, so it is determined to execute a pitch action of quickly increasing the pitch angle (towards feathering) once, for example, quickly increasing from the current operating pitch angle of 2° by 2° to 4°, with the rate being the maximum rate allowed by the system and the mode being a single quick jitter. Subsequently, the system executes the determined pitch action, controlling the pitch actuator to quickly change the blade pitch angle from 2° to 4° and quickly return to 2°. This action utilizes the gravity component and the additional force generated by pitching to promote the ice-melting water to be flung off the blade surface.

[0092] In some of the above embodiments of the present application, it is proposed to remove the melted ice and water on the blade surface by means of a pitch action. Specifically, when it is evaluated that the risk of re-freezing of the melted ice and water meets the set trigger conditions, a set pitch action is executed. By changing the force acting on the melted ice and water, the set pitch action promotes the removal of the melted ice and water from the blade, which can reduce the risk of re-freezing of the melted ice and water. However, in the process of its implementation, during the actual execution of the pitch action, due to the uneven distribution of the melted ice and water, the complex structure of the blade surface, and the possible execution errors of the pitch action itself, relying solely on the preset pitch parameters may not ensure the full removal of the melted ice and water. In addition, due to the lack of real-time feedback on the removal effect of the melted ice and water, it is difficult for the control system to determine whether the current pitch action is effective and whether adjustment or supplementation is required, which may lead to the residual of some melted ice and water and increase the risk of re-freezing.

[0093] In response, the present application further proposes that the steps of executing a determined pitch action include: When executing the determined pitch action, monitor the operating parameters of the drive mechanism that drives the blade to pitch, and obtain the monitored operating parameters of the drive mechanism; Compare the monitored operating parameters of the drive mechanism or the characteristic quantity calculated based on the monitored operating parameters of the drive mechanism with the preset reference operating parameters of the drive mechanism when the blade executes the same type of pitch action in the state where the melted ice and water have been removed, and obtain a comparison result; If the comparison result indicates that the melted ice and water are not sufficiently thrown off, execute a supplementary pitch action or adjust the parameters of the subsequent pitch action to promote the removal of the melted ice and water.

[0094] Among them, monitoring the operating parameters of the drive mechanism that drives the blade to pitch refers to obtaining the working state data of the power component responsible for changing the blade pitch angle in the wind turbine during the execution of the pitch action. It can be achieved by monitoring physical quantities such as the drive current, drive voltage, power consumption, output torque, or hydraulic system pressure of the pitch motor or hydraulic system. The purpose is to obtain real-time information reflecting the load state of the drive mechanism; The monitored operating parameters of the drive mechanism refer to the original working state data of the drive mechanism obtained through monitoring. It can be achieved by the numerical values or time series obtained by devices such as current sensors, voltage sensors, power meters, torque sensors, or pressure sensors. The purpose is to provide direct data for subsequent analysis and comparison; The characteristic quantity calculated based on the operating parameters of the drive mechanism during monitoring refers to a specific index extracted from the original monitoring data that can more significantly or stably reflect the load change of the drive mechanism. It can be achieved by calculating the peak value, average value, integral value over a period of time, change rate, etc. of the operating parameters during the pitch change process. Its purpose is to enhance the sensitivity to the blade load change and the accuracy of comparison; The preset reference of the operating parameters of the drive mechanism when the blade performs the same type of pitch change action in the state where the melting ice and water have been removed refers to the pre-determined normal operating parameter range or typical value of the drive mechanism when there is no melting ice and water attached to the blade surface or the melting ice and water have been fully removed during the execution of the same pitch change action. It can be established and obtained by analyzing historical operating data, performing theoretical modeling calculations, or conducting calibration tests under clean blade conditions, etc. Its purpose is to provide a reference standard for evaluating the current state of melting ice and water removal; The comparison result indicating that the melting ice and water are not sufficiently thrown off refers to the judgment conclusion obtained by comparing the currently monitored operating parameters of the drive mechanism or their characteristic quantities with the preset reference. This conclusion indicates that the current pitch change action fails to effectively remove the melting ice and water on the blade surface. It can be achieved by judging whether the difference between the monitored value and the reference exceeds the preset threshold, etc. Its purpose is to provide a decision-making basis for whether further intervention measures are needed; The supplementary pitch change action refers to one or more additional pitch change action sequences executed after the original pitch change action is completed to further remove the residual melting ice and water. It can be achieved by executing one or more additional pitch change action sequences targeted at removing the residual melting ice and water. Its purpose is to perform remedial removal of the melting ice and water that have not been sufficiently removed; Adjusting the parameters of subsequent pitch change actions refers to modifying the parameters of the pitch change actions to be executed subsequently in the plan according to the evaluation result of the current melting ice and water removal effect. It can be achieved by increasing the pitch change amplitude, speed, duration, or changing the specific action mode, etc. Its purpose is to improve the melting ice and water removal efficiency of subsequent pitch change attempts.

[0095] The solution of this application monitors the operating parameters of the drive mechanism that drives the blade pitch during pitching maneuvers aimed at removing meltwater in real time. These parameters indirectly reflect the load status of the blade surface, including the presence of meltwater. These monitored parameters, or characteristic quantities calculated based on them, are compared with a preset baseline of drive mechanism operating parameters representing a clean blade state, thereby quantitatively evaluating the effectiveness of the current pitching maneuver on removing meltwater. This indirect evaluation mechanism, based on the drive mechanism's own operating information, enables the system to determine whether meltwater has been adequately removed without relying on additional sensors on the blade surface. Furthermore, if the comparison indicates insufficient meltwater removal, the system can automatically trigger additional pitching maneuvers or adjust the parameters of subsequent pitching maneuvers based on this feedback. This closed-loop feedback adjustment based on effect evaluation enables the meltwater removal process to be self-correcting and optimized. Compared to open-loop control that only executes a preset program, this solution significantly improves the thoroughness and success rate of meltwater removal by introducing real-time evaluation of the removal effect and adaptive intervention based on the evaluation results. This approach, combined with the previous solution's technical means of removing meltwater through pitch action, forms a more intelligent and robust meltwater management strategy that can more effectively address the problem of meltwater refreezing and ensure that the blades truly return to a safe operating state after heating and de-icing.

[0096] In some of the aforementioned embodiments of the present application, after a combination of pitch-assisted de-icing trigger conditions is met, the amplitude, rate, and pattern of the pitch action are determined based on the acquired real-time rotational azimuth angle of the blade and preset de-icing efficiency adjustment logic, and the determined pitch action is executed. Specifically, the determined pitch action may be to control the blade pitch angle to rapidly change within a small range based on the current operating pitch angle, such as increasing or decreasing by a few degrees, and to use a higher pitch rate. This can utilize the additional centrifugal force component changes and transient aerodynamic disturbances generated by the pitch change to promote the removal of de-icing water from the blade. However, during this implementation, the distribution of de-icing water on the blade surface is uneven, especially in the spanwise direction of the blade, where the de-icing water may be concentrated in certain areas. Simply executing the pitch action may not fully utilize the various forces (e.g., gravity and centrifugal force) during blade rotation to enhance the removal of de-icing water, resulting in reduced efficiency of the pitch action and even requiring multiple pitch changes to achieve the desired de-icing effect, thereby increasing energy consumption and the burden on the actuator.

[0097] In this regard, the present application further proposes that the steps of executing the determined pitch change action include: Based on parameters related to the blade heating process or historical ice coverage information of the blade, the concentrated distribution area of meltwater in the blade span direction is estimated; Obtain the real-time rotation azimuth angle of the blade; Based on the predicted concentrated distribution area of the melted ice water in the spanwise direction of the blade and the variation characteristics of the forces acting on the concentrated distribution area during the rotation of the blade, at least one predetermined rotation azimuth angle interval is determined. The selection of the predetermined rotation azimuth angle interval aims to execute the determined pitch action when the predicted concentrated distribution area of the melted ice water is within this interval, with the goal of utilizing or enhancing the removal force acting on the melted ice water. When the real-time rotation azimuth angle of the obtained blade enters at least one predetermined rotation azimuth angle interval, execute the determined pitch action.

[0098] Among them, predicting the concentrated distribution area of the melted ice water in the spanwise direction of the blade based on parameters related to the blade heating process or the blade historical icing information means predicting the possible positions where the melted ice water may accumulate in large quantities in the blade length direction by analyzing the operation data of the blade heating system or the performance of the blade in past icing events. It can be achieved by analyzing parameters such as the heating power and heating duration of each heating area, or by consulting the historical icing frequency and thickness records of specific blade areas. Its purpose is to obtain the position information where the melted ice water may accumulate in the blade length direction. Among them, the blade historical icing information refers to the recorded data such as the ice layer characteristics, distribution positions, melting and shedding conditions formed on the blade in past icing events. It can be obtained and stored by means such as sensor recording, image analysis or manual inspection recording. Its purpose is to provide a historical data basis for predicting the concentrated distribution area of the melted ice water in the spanwise direction of the blade. Among them, the concentrated distribution area in the spanwise direction of the blade refers to the specific area on the blade along its length direction where the melted ice water is prone to converge, stay or flow slowly due to factors such as gravity, centrifugal force, air flow or blade geometry. It can be one or more spanwise positions or ranges. Its purpose is to clarify the positions where the melted ice water may exist in large quantities and provide targeted information for optimizing the pitch execution timing subsequently. Among them, the variation characteristics of the forces acting on the concentrated distribution area during the blade rotation refer to the law of the magnitude and direction of the resultant force of gravity, centrifugal force, aerodynamic force, etc. acting on a specific area in the spanwise direction of the blade changing with the blade rotation azimuth angle during one revolution of the blade with the hub. It can be obtained by means such as physical modeling, simulation calculation or empirical data analysis. Its purpose is to identify at which rotation azimuth angles these forces have the most significant removal effect on the melted ice water. Among them, at least one predetermined rotation azimuth angle interval refers to one or more pre-determined angular ranges in the blade rotation plane. When the real-time rotation azimuth angle of the blade falls into these intervals, it is considered an opportune time to execute the pitch action to facilitate the removal of the melted ice water. It can be calculated or determined by looking up a table based on the predicted concentrated distribution area of the melted ice water and the variation characteristics of the forces. Its purpose is to plan the optimal timing window for executing the pitch action. Among them, the selection of the predetermined rotation azimuth angle interval is based on the principle that when the estimated concentrated distribution area of the melted ice and water is within this interval, the determined pitch action is executed, and the goal is to utilize or enhance the removal force acting on the melted ice and water. That is, when determining the above-mentioned predetermined rotation azimuth angle interval, the selected interval should be such that when the pitch action is executed within this interval, the natural forces (such as gravity and centrifugal force) generated by the blade rotation can act synergistically with the force generated by the pitch action, or the effect of the pitch action on the melted ice and water itself is better at these azimuth angles. It can be selected using an optimization algorithm or based on empirical rules, and its purpose is to ensure that the pitch action occurs at the moment most conducive to the removal of the melted ice and water.

[0099] Based on the solution of the present application, during the blade heating and deicing process of the wind turbine generator, the risk of re-freezing of the melted ice and water is evaluated, and when the risk meets the trigger condition, on the basis of determining and executing the pitch action to promote the removal of the melted ice and water, the execution timing of the pitch action is further optimized.

[0100] Specifically, the solution first estimates the area where the melted ice and water may concentrate in the blade span direction according to the parameters related to the blade heating process or the historical icing information of the blade. At the same time, the system continuously obtains the real-time rotation azimuth angle of the blade. When the pitch action needs to be executed, the solution does not execute immediately, but determines one or more predetermined rotation azimuth angle intervals according to the estimated concentrated distribution area of the melted ice and water and the change characteristics of the forces acting on this area during the blade rotation, such as the gravity component, centrifugal force, etc. The selection goal of these intervals is that when the estimated concentrated area of the melted ice and water is within these intervals, the pitch action is executed, and the natural force generated by the blade rotation can be utilized or the removal effect of the pitch action itself on the melted ice and water can be enhanced. Finally, when the obtained real-time rotation azimuth angle of the blade enters these predetermined intervals, the system triggers the execution of the previously determined pitch action. This way combines the execution of the pitch action with the favorable attitude of the blade rotation, enables the pitch action to act on the position where the melted ice and water are most likely to gather, and occurs at the moment most conducive to its removal, thereby increasing the amount of melted ice and water removed by a single pitch operation and enhancing the overall melted ice and water removal efficiency.

[0101] In the second aspect, referring to Figure 2 , the present application further proposes a pre-control system for icing on the blades of a wind turbine generator, which system includes: An acquisition module 210, configured to acquire the operating parameters and environmental data of the wind turbine generator during the blade heating and deicing process; An evaluation module 220, configured to evaluate the re-freezing risk of the melted ice and water generated on the blade surface based on the operating parameters and environmental data, and obtain the evaluated re-freezing risk; A control module 230, configured to control a wind turbine generator set to perform a set pitch action when the evaluated refreezing risk meets a set trigger condition, and the set pitch action promotes the removal of the ice-melting water from the blade by changing the force acting on the ice-melting water.

[0102] By evaluating the refreezing risk of the ice-melting water and performing a pitch action when the risk meets the condition, using the pitch to change the force acting on the ice-melting water and promoting the removal of the ice-melting water, thereby reducing or avoiding refreezing, it has the advantages of being able to effectively reduce or avoid the refreezing risk of the ice-melting water on the blade surface, improving the de-icing effect and ensuring the safety of the unit.

[0103] In addition, in some preferred embodiments, a pre-control system for icing of a wind turbine generator set blade proposed in the present application can perform any one of the steps in the above method.

[0104] The above are only embodiments of the present application and are not used to limit the protection scope of the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for pre - controlling icing on the blades of a wind turbine generator, characterized in that, Including: Obtaining the operating parameters and environmental data of a wind turbine during the blade heating and de-icing process; Based on the operating parameters and the environmental data, evaluating the re-freezing risk of the melted ice water generated on the blade surface to obtain the evaluated re-freezing risk; When the evaluated re-freezing risk meets the set trigger condition, performing a set pitch action, and the set pitch action promotes the removal of the melted ice water from the blade by changing the force acting on the melted ice water.

2. The method for pre-controlling icing on the blade of a wind turbine generator according to claim 1, wherein The step of performing the set pitch action, and the set pitch action promotes the removal of the melted ice water from the blade by changing the force acting on the melted ice water includes: Estimating the spanwise distribution area of the melted ice water on the blade surface; Obtaining the real-time rotational azimuth angle of the blade; Based on the estimated spanwise distribution area of the melted ice water on the blade surface, determining a predetermined azimuth angle interval such that when the blade rotates and the estimated spanwise distribution area of the melted ice water is within the predetermined azimuth angle interval, the resultant force acting on the melted ice water causes it to be removed from the blade; When the obtained real-time rotational azimuth angle of the blade is within the predetermined azimuth angle interval, performing the set pitch action to promote the removal of the melted ice water from the blade by changing the force acting on the melted ice water.

3. The ice accretion pre-control method for the wind turbine blade according to claim 2, wherein The step of based on the estimated spanwise distribution area of the melted ice water on the blade surface, determining a predetermined azimuth angle interval such that when the blade rotates and the estimated spanwise distribution area of the melted ice water is within the predetermined azimuth angle interval, the resultant force acting on the melted ice water causes it to be removed from the blade includes: Obtaining the geometric feature information of the blade; Obtaining the fluid action information during the blade rotation process; Based on the geometric feature information of the blade, the fluid action information during the blade rotation process, and the estimated spanwise distribution area of the melted ice water on the blade surface, judging which force component or combination of force components acting on the estimated spanwise distribution area of the melted ice water is helpful for the removal of the melted ice water at different azimuth angles of the blade rotation, and obtaining the force component or combination of force components helpful for the removal of the melted ice water and the corresponding rotational azimuth angle; Based on the force component or combination of force components helpful for the removal of the melted ice water, the corresponding rotational azimuth angle, and the estimated spanwise distribution area of the melted ice water on the blade surface, determining the predetermined azimuth angle interval.

4. The method for pre-controlling icing of a wind turbine blade according to claim 3, wherein, The step of based on the geometric feature information of the blade, the fluid action information during the blade rotation process, and the estimated spanwise distribution area of the melted ice water on the blade surface, judging which force component or combination of force components acting on the estimated spanwise distribution area of the melted ice water is helpful for the removal of the melted ice water at different azimuth angles of the blade rotation, and obtaining the force component or combination of force components helpful for the removal of the melted ice water and the corresponding rotational azimuth angle includes: Obtaining a parameter set related to the estimated spanwise distribution area of the melted ice water on the blade surface, which can reflect the aggregation state or flow characteristics of the melted ice water; Based on the parameter set, identifying the physical form of the melted ice water in the estimated spanwise distribution area of the melted ice water on the blade surface; Based on the geometric feature information of the blade, the fluid action information during the rotation of the blade, the predicted spanwise distribution area of the melting ice water on the blade surface, and the identified physical form of the melting ice water, determine which force component or combination of force components acting on the predicted spanwise distribution area of the melting ice water at different azimuth angles during blade rotation contributes to the removal of the melting ice water, and obtain the force component or combination of force components that matches the removal characteristics of the identified physical form of the melting ice water and the corresponding rotation azimuth angle.

5. The method for pre-controlling icing on a wind turbine blade according to claim 4, wherein The step of obtaining a set of parameters related to the predicted spanwise distribution area of the melting ice water on the blade surface and capable of reflecting the aggregation state or flow characteristics of the melting ice water includes: Obtain the operating parameters of the wind turbine generator set; Obtain environmental data; Obtain the pre-stored correlation information on the formation and evolution law of the melting ice water on the blade surface; Based on the obtained operating parameters of the wind turbine generator set, the obtained environmental data, and the obtained pre-stored correlation information on the formation and evolution law of the melting ice water on the blade surface, infer the predicted thickness, coverage area ratio, and flow velocity range of the melting ice water in the predicted spanwise distribution area of the melting ice water on the blade surface; Take the inferred predicted thickness, coverage area ratio, and flow velocity range as a set of parameters related to the predicted spanwise distribution area of the melting ice water on the blade surface and capable of reflecting the aggregation state or flow characteristics of the melting ice water.

6. The method for pre - controlling icing of a wind turbine blade according to claim 1, wherein, The step of evaluating the re-freezing risk of the melting ice water generated on the blade surface based on the operating parameters and the environmental data to obtain the evaluated re-freezing risk includes: Based on the operating parameters and the preset physical property parameters, estimate the amount of melting ice water formed on the blade surface; Identify specific areas on the blade where the melting ice water is prone to retention or the surface temperature is prone to decrease due to geometric structure or airflow influence as the key areas for risk assessment; Based on the operating parameters, the environmental data, and the characteristics of the identified key areas, analyze the current surface temperature state of the key areas; Based on the operating parameters, the environmental data, combined with the estimated amount of melting ice water and the analyzed current surface temperature state of the key areas, evaluate the re-freezing risk of the melting ice water generated on the blade surface in the key areas to obtain the evaluated re-freezing risk.

7. The method for pre-controlling icing on the blade of a wind turbine according to claim 6, characterized in that, The method further includes: Obtain the estimated total amount of melting ice water on the blade surface, the stage information of the current heating process, and the real-time rotation azimuth angle of the blade; Based on the obtained estimated total amount of melting ice water on the blade surface, the stage information of the current heating process, the evaluated re-freezing risk, and the obtained real-time rotation azimuth angle of the blade, determine whether the preset combination of pitch assist drainage trigger conditions is satisfied; If it is determined that the preset combination of pitch assist drainage trigger conditions is satisfied, then based on the obtained real-time rotation azimuth angle of the blade and the preset drainage efficiency adjustment logic, determine the amplitude, rate, and mode of the pitch action; Execute the determined pitch action.

8. The ice accretion pre-control method for the wind turbine blade according to claim 7, wherein, The step of executing the determined pitch action includes: When performing the determined pitch action, monitor the operating parameters of the drive mechanism that drives the blade to pitch, and obtain the monitored operating parameters of the drive mechanism; Compare the monitored operating parameters of the drive mechanism or the characteristic quantity calculated based on the monitored operating parameters of the drive mechanism with a preset reference of the operating parameters of the drive mechanism when the blade performs the same type of pitch action in the state where the melting ice and water have been removed, and obtain a comparison result; If the comparison result indicates that the melting ice and water are not sufficiently thrown off, perform a supplementary pitch action or adjust the parameters of the subsequent pitch action to promote the removal of the melting ice and water.

9. The ice accretion pre-control method for the blade of a wind turbine according to claim 7, wherein The step of performing the determined pitch action includes: Based on the parameters related to the blade heating process or the blade historical icing information, estimate the concentrated distribution area of the melting ice and water in the blade span direction; Obtain the real-time rotational azimuth angle of the blade; According to the estimated concentrated distribution area of the melting ice and water in the blade span direction and the change characteristics of the force acting on the concentrated distribution area during the rotation of the blade, determine at least one predetermined rotational azimuth angle interval. The selection of the predetermined rotational azimuth angle interval is aimed at being able to utilize or enhance the removal force acting on the melting ice and water when the estimated concentrated distribution area of the melting ice and water is in this interval and perform the determined pitch action; When the obtained real-time rotational azimuth angle of the blade enters the at least one predetermined rotational azimuth angle interval, perform the determined pitch action.

10. A blade icing pre-control system for a wind turbine generator, characterized in that, The system includes: An acquisition module for acquiring the operating parameters and environmental data of the wind turbine during the blade heating and de-icing process; An evaluation module for evaluating the re-freezing risk of the melting ice and water generated on the blade surface on the blade based on the operating parameters and the environmental data, and obtaining the evaluated re-freezing risk; A control module for controlling the wind turbine to perform a set pitch action when the evaluated re-freezing risk meets the set trigger condition. The set pitch action promotes the removal of the melting ice and water from the blade by changing the force acting on the melting ice and water.

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