A wind turbine blade icing pre-control method and system

Abstract

The application provides a wind turbine blade icing pre-control method and system, and relates to the technical field of wind turbine control. The technical scheme points are: obtaining operation parameters and environmental data of a wind turbine during a blade heating de-icing process; based on the operation parameters and the environmental data, evaluating the risk of re-freezing of ice-melting water generated on the blade surface, obtaining an evaluated re-freezing risk; when the evaluated re-freezing risk meets a set triggering condition, performing a set pitch action, and the set pitch action promotes the ice-melting water to be removed from the blade by changing the force acting on the ice-melting water. The wind turbine blade icing pre-control method and system provided by the application have the advantages.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind turbine control, in particular to a wind turbine blade icing pre-control method and system. BACKGROUND

[0002] When the wind turbine operates in low temperature and high humidity weather conditions, icing phenomenon is prone to occur on the surface of the blade. The icing of the blade will significantly change its original aerodynamic shape, resulting in a decrease in lift coefficient and an increase in drag coefficient, which seriously affects the effective capture of wind energy and reduces the power generation efficiency. In addition, uneven icing will destroy the mass balance of the blade, generate a large amount of unbalanced load in the high-speed rotating process, and cause fatigue damage of key components such as blade, hub, main shaft, gear box and tower, and even may lead to catastrophic structural damage accidents. In order to ensure the safe and stable operation of the wind turbine in the icing environment, a blade icing pre-control system is usually equipped.

[0003] In the existing blade icing pre-control technology, active heating de-icing is a common means. By arranging heating elements inside or on the surface of the blade, the heating is started when the icing risk or the formed ice is detected, so that the temperature of the blade surface is raised above the freezing point, thereby preventing the formation of ice or melting the existing ice layer. This method can restore the aerodynamic performance of the blade to some extent.

[0004] However, in the process of using heating method for icing pre-control or de-icing, a large amount of ice melting water will be generated. Under the action of gravity and centrifugal force generated by the rotation of the blade, the ice melting water will flow along the surface of the blade to the tip or trailing edge of the blade. Due to the complex three-dimensional geometry of the wind turbine blade and the varying airflow acting on it in different operating states, the flow path of the ice melting water is not always smooth. Especially in the trailing edge, wing tip and other areas of the blade, or in the presence of small defects on the surface of the blade, the ice melting water is prone to slow flow, accumulation or even stagnation.

[0005] Further problems are that even if the main body area of the blade is kept above the freezing point by heating, the temperature of some specific areas where the ice melting water flows through or converges may still be low. For example, the sharp edges of the trailing edge of the blade, the complex curved surface area of the wing tip, or the end or weak link covered by the heating system, the temperature of these parts may be low due to the strong cooling effect of local airflow or faster heat dissipation, even below the freezing point. When the ice melting water from the warmer area flows to these low temperature areas, re-freezing phenomenon is prone to occur, forming new ice layer, i.e. secondary ice.

[0006] The secondary ice formed by the re-freezing of the melted ice water is often irregular in shape and can form ice ridges or ice accretions, which have 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 the initial ice accretion, and its distribution is local and uncertain. Existing ice pre-control systems usually mainly focus on the detection of initial ice accretion and overall heating strategy, and lack effective monitoring means for the dynamic behavior of the melted ice water during the heating process, and also fail to fully consider the risk of re-freezing of the melted ice water in a specific area. The system may stop working after completing the preset heating period, but the re-freezing process in the local area may still be in progress or new ice accretion may have been formed.

[0007] The secondary ice that fails to be removed in time will become a new ice accretion core, accelerating the accumulation of subsequent ice accretion and leading to the persistence or aggravation of the ice accretion problem in a specific area of the blade. In addition, irregular secondary ice may generate more complex and unpredictable unbalanced loads, posing a potential threat to the safe operation of the unit. The existing technology lacks effective and low-cost active intervention strategies for the diversion, discharge and prevention of local re-freezing of the melted ice water after heating and de-icing.

[0008] The existing technology needs to be improved in view of the above problems. SUMMARY

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

[0010] In a first aspect, the present application provides a wind turbine blade ice pre-control method, and the technical solution is as follows:

[0011] It comprises:

[0012] Obtaining the operating parameters of the wind turbine during the heating and de-icing process of the blade and the environmental data;

[0013] Based on the operating parameters and the environmental data, the re-freezing risk of the melted ice water generated on the blade surface is evaluated, and the evaluated re-freezing risk is obtained.

[0014] When the evaluated re-freezing risk meets the set triggering condition, a set pitch action is performed, and the set pitch action changes the force acting on the melted ice water to promote the removal of the melted ice water from the blade.

[0015] Further, in the present application, the step of performing the set pitch action, which changes the force acting on the melted ice water to promote the removal of the melted ice water from the blade, comprises:

[0016] estimate the spanwise distribution area of the de-icing water on the blade surface;

[0017] obtain the real-time rotating azimuth angle of the blade;

[0018] determine a predetermined azimuth angle interval based on the estimated spanwise distribution area of the de-icing water on the blade surface, so that when the blade rotates and the estimated spanwise distribution area of the de-icing water is in the predetermined azimuth angle interval, the resultant force acting on the de-icing water removes it from the blade;

[0019] when the obtained real-time rotating azimuth angle of the blade is in the predetermined azimuth angle interval, execute the set pitch action to promote the de-icing water to be removed from the blade by changing the force acting on the de-icing water.

[0020] Further, in the present application, the step of determining a predetermined azimuth angle interval based on the estimated spanwise distribution area of the de-icing water on the blade surface, so that when the blade rotates and the estimated spanwise distribution area of the de-icing water is in the predetermined azimuth angle interval, the resultant force acting on the de-icing water removes it from the blade, comprises:

[0021] obtain the geometric feature information of the blade;

[0022] obtain the fluid action information of the blade rotating process;

[0023] based on the geometric feature information of the blade, the fluid action information of the blade rotating process, and the estimated spanwise distribution area of the de-icing water on the blade surface, determine which force component or combination of force components acting on the estimated spanwise distribution area of the de-icing water is conducive to the removal of the de-icing water at different azimuth angles of the blade rotating, to obtain the force component or combination of force components conducive to the removal of the de-icing water and the corresponding rotating azimuth angle;

[0024] determine the predetermined azimuth angle interval based on the force component or combination of force components conducive to the removal of the de-icing water, the corresponding rotating azimuth angle, and the estimated spanwise distribution area of the de-icing water on the blade surface.

[0025] Further, in the present application, the step of determining a predetermined azimuth angle interval based on the geometric feature information of the blade, the fluid action information of the blade rotating process, and the estimated spanwise distribution area of the de-icing water on the blade surface, so that when the blade rotates and the estimated spanwise distribution area of the de-icing water is in the predetermined azimuth angle interval, the resultant force acting on the de-icing water removes it from the blade, comprises:

[0026] obtain a parameter set related to the estimated spanwise distribution area of the ice-melting water on the blade surface, which can reflect the accumulation state or flow characteristics of the ice-melting water;

[0027] identify the physical form of the ice-melting water in the estimated spanwise distribution area of the ice-melting water on the blade surface according to the parameter set;

[0028] determine, based on the geometric feature information of the blade, the fluid action information of the blade rotation process, the estimated spanwise distribution area of the ice-melting water on the blade surface, and the identified physical form of the ice-melting water, which force component or combination of force components acting on the estimated spanwise distribution area of the ice-melting water is conducive to the removal of the ice-melting water at different azimuth angles of blade rotation, to obtain a force component or combination of force components and a corresponding rotation azimuth angle that match the removal characteristics of the identified physical form of the ice-melting water.

[0029] Further, in the present application, the step of obtaining a parameter set related to the estimated spanwise distribution area of the ice-melting water on the blade surface, which can reflect the accumulation state or flow characteristics of the ice-melting water, comprises:

[0030] obtaining an operating parameter of the wind turbine generator set;

[0031] obtaining environmental data;

[0032] obtaining associated information of pre-stored ice-melting water formation and evolution rules on the blade surface;

[0033] inferring the estimated thickness, coverage area ratio, and flow velocity range of the ice-melting water in the estimated spanwise distribution area of the ice-melting water on the blade surface based on the obtained operating parameter of the wind turbine generator set, the obtained environmental data, and the obtained associated information of the pre-stored ice-melting water formation and evolution rules on the blade surface;

[0034] using the inferred estimated thickness, coverage area ratio, and flow velocity range as the parameter set related to the estimated spanwise distribution area of the ice-melting water on the blade surface, which can reflect the accumulation state or flow characteristics of the ice-melting water.

[0035] Further, in the present application, the step of evaluating the re-freezing risk of the ice-melting water generated on the blade surface based on the operating parameter and the environmental data to obtain an evaluated re-freezing risk comprises:

[0036] estimating the amount of ice-melting water formed on the blade surface based on the operating parameter and pre-set physical property parameters;

[0037] identifying specific areas on the blade where ice-melt water is prone to stay or surface temperature is prone to decrease due to geometric configuration or air flow effect as key areas for risk assessment;

[0038] analyzing current surface temperature status of the key areas based on the operating parameters, the environmental data, and characteristics of the identified key areas;

[0039] evaluating re-freezing risk of ice-melt water generated on the blade surface in the key areas based on the operating parameters, the environmental data, in combination with the estimated ice-melt water amount and the analyzed current surface temperature status of the key areas, to obtain the evaluated re-freezing risk.

[0040] Further, in the present application, the method further comprises:

[0041] obtaining an estimated total ice-melt water amount on the blade surface, stage information of a current heating process, and a real-time rotation azimuth angle of the blade;

[0042] based on the obtained estimated total ice-melt water amount 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, determining whether a preset combination of pitch-assisted drainage triggering conditions is met;

[0043] if it is determined that the combination of pitch-assisted drainage triggering conditions is met, determining an amplitude, a rate, and a mode of a pitch action based on the obtained real-time rotation azimuth angle of the blade and a preset drainage efficiency adjustment logic;

[0044] performing the determined pitch action.

[0045] Further, in the present application, the step of performing the determined pitch action comprises:

[0046] monitoring operating parameters of a driving mechanism driving the blade to pitch while performing the determined pitch action, to obtain monitored driving mechanism operating parameters;

[0047] comparing the monitored driving mechanism operating parameters or a feature quantity calculated based on the monitored driving mechanism operating parameters with a preset driving mechanism operating parameter benchmark representing the driving mechanism operating parameters when the same type of pitch action is performed on the blade in an ice-melt water-removed state, to obtain a comparison result;

[0048] if the comparison result indicates that ice-melt water is not sufficiently thrown off, performing a supplementary pitch action or adjusting parameters of a subsequent pitch action to facilitate removal of the ice-melt water.

[0049] Further, in the present application, the step of performing the determined pitch action comprises:

[0050] estimate a concentrated distribution area of the de-icing water in the spanwise direction of the blade based on parameters related to the blade heating process or blade icing history information;

[0051] obtain a real-time rotation azimuth angle of the blade;

[0052] determine at least one predetermined rotation azimuth angle interval according to the estimated concentrated distribution area of the de-icing water in the spanwise direction of the blade and the variation characteristics of the force acting on the concentrated distribution area during the rotation of the blade, the selection of the predetermined rotation azimuth angle interval being targeted at executing the determined pitch action when the estimated concentrated distribution area of the de-icing water is in the interval, and the removal force acting on the de-icing water being targeted at being utilized or enhanced;

[0053] execute the determined pitch action when the obtained real-time rotation azimuth angle of the blade enters the at least one predetermined rotation azimuth angle interval.

[0054] In a second aspect, the present application further provides a wind turbine blade icing pre-control system, which comprises:

[0055] an obtaining module configured to obtain operation parameters and environmental data of a wind turbine during a blade heating de-icing process;

[0056] an evaluation module configured to evaluate a refreezing risk of de-icing water generated on the surface of the blade based on the operation parameters and the environmental data, and obtain an evaluated refreezing risk;

[0057] a control module configured to control the wind turbine to execute a set pitch action when the evaluated refreezing risk meets a set triggering condition, the set pitch action changing the force acting on the de-icing water to promote the removal of the de-icing water from the blade.

[0058] As can be seen from the above, the wind turbine blade icing pre-control method and system provided by the present application can evaluate the refreezing risk of de-icing water and execute a pitch action when the risk meets a condition, utilize the pitch to change the force acting on the de-icing water, and promote the removal of the de-icing water, thereby reducing or avoiding refreezing, and having the advantages of being capable of effectively reducing or avoiding the refreezing risk of de-icing water on the surface of the blade, improving the de-icing effect, and ensuring the safety of the unit. BRIEF DESCRIPTION OF DRAWINGS

[0059] Figure 1 A flowchart of a wind turbine blade icing pre-control method provided by the present application is shown.

[0060] Figure 2 A structural diagram of a wind turbine blade icing pre-control system provided by the present application is shown.

[0061] In the figure: 210, acquisition module; 220, evaluation module; 230, control module. DETAILED DESCRIPTION

[0062] The technical solutions in the present application will be described clearly and completely below in combination with the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. The components of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0063] It should be noted that: similar reference numbers and letters represent similar items in the following drawings, so 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 to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0064] When the conventional existing icing pre-control system of wind turbine generator unit adopts heating method for icing pre-control or de-icing, there is a problem of retention and re-freezing of ice-melting water on the surface area of the blade. The flow path of ice-melting water is blocked due to the blade geometry, centrifugal force generated by rotation and air flow, which is easy to accumulate in the trailing edge, wing tip and other areas. Even if the heating system makes the temperature of most areas higher than the freezing point, these areas may have lower temperature due to local cooling effect or limitation of heating coverage. When the ice-melting water flows through or converges to these low-temperature areas, re-freezing may occur, forming secondary ice. The secondary ice differs from the initial icing in form and nature, and may have adhesion, and the existing system lacks means to identify and handle it.

[0065] For example, assume a wind turbine is operating at 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 electric heating system to de-ice the blade. The heating causes the ice on the leading edge and mid-span region of the blade to melt, producing meltwater. This meltwater flows towards the tip and trailing edge of the blade under the action of gravity and centrifugal force. However, at the edge region of the trailing edge of the blade, the local heat loss increases due to the acceleration of the airflow, and even though the heating system is still working, the surface temperature of this region may remain close to or below 0°C. When the meltwater accumulates in this region, part of the water flow slows down and begins to refreeze under the action of low temperature, forming ice ridges. At this time, the heating system may have entered a power reduction phase or is about to stop, and the system determines that the primary ice cover has been removed, but secondary ice is still forming or has already formed on the trailing edge of the blade. The secondary ice changes the aerodynamic profile of the trailing edge of the blade, which can cause local airflow separation, increase resistance, and produce aerodynamic noise. At the same time, the ice ridges increase the imbalance of the blade mass, generating vibration loads when rotating.

[0066] If the above problems are not addressed, the secondary ice formed by the refreezing of meltwater produced during the heating de-icing process of the wind turbine blade will affect the aerodynamic performance of the blade, leading to a decrease in energy capture efficiency. Secondary ice can cause or exacerbate the imbalance of the blade, causing fatigue damage to components such as the hub, main shaft, gearbox, etc., and shortening the service life of the equipment. The shedding of secondary ice can pose a threat to the surrounding environment and personnel safety. In addition, the secondary ice that is not removed can become the starting point for subsequent icing, accelerating the formation of a new round of icing, making the blade icing problem recur, increasing the de-icing frequency and energy consumption. The existing pre-control system lacks the ability to perceive and handle local refreezing, and cannot ensure that the blade returns to a safe operating state without significant icing after the de-icing operation is completed.

[0067] To this end, with reference to Figure 1 , the present application proposes a wind turbine blade icing pre-control method, comprising:

[0068] S110, obtaining operating parameters of the wind turbine during the blade heating de-icing process and environmental data;

[0069] S120, based on the operating parameters and the environmental data, evaluating the refreezing risk of the meltwater produced on the blade surface on the blade, to obtain the evaluated refreezing risk;

[0070] S130, when the evaluated refreezing risk meets the set triggering condition, performing a set pitch action, the set pitch action changes the force acting on the meltwater to promote the removal of the meltwater from the blade.

[0071] The operating parameters are data reflecting the working state of the wind turbine during the blade heating deicing stage, such as pitch angle, rotor speed, heating system working power, etc., and are mainly used to obtain basic information required for risk assessment.

[0072] The environmental data are conditions of the external environment in which the wind turbine is located, such as ambient temperature, humidity, wind speed, etc., and are mainly used to obtain basic information required for risk assessment.

[0073] The re-freezing risk assessment is to predict the possibility of re-freezing of the ice-melting water on the blade surface in a specific area of the blade by using the obtained operating parameters and environmental data, combined with a preset model or logic, and is mainly used to provide a basis for decision-making on whether to take intervention measures subsequently.

[0074] The set trigger condition is a pre-set condition for determining the timing of taking the pitch action when the assessed re-freezing risk reaches a certain state or meets a specific combination condition, and is mainly used to ensure that intervention measures are started in time when the risk is high.

[0075] The set pitch action is one or more blade pitch angle adjustment sequences specially designed for removing ice-melting water, which can be achieved by rapid small-amplitude pitch angle changes, such as temporary increase or decrease based on the current pitch angle, and is mainly used to promote the movement or separation of ice-melting water from the blade surface by changing the force (such as centrifugal force, aerodynamic force component) acting on the ice-melting water.

[0076] The core innovation of the present application is that by combining the re-freezing risk assessment based on operating parameters and environmental data with the specific action of the existing pitch system of the wind turbine, active intervention in the re-freezing risk of ice-melting water during the heating deicing process is achieved without relying on additional sensors on the blade surface, and the effect of effectively inhibiting secondary ice formation is achieved.

[0077] The solution of the present application takes the operating parameters and environmental data of the wind turbine under certain working conditions as input, and uses these data to evaluate the risk of re-freezing of the ice-melt water on the blade surface. This evaluation process is based on the analysis and judgment of existing information, rather than direct measurement of the state of ice-melt water. Once the evaluation result shows that the re-freezing risk reaches the predetermined trigger condition, the system activates the pitch system of the wind turbine and controls the blade to perform a preset pitch action sequence specially designed for removing ice-melt water. This pitch action changes the attitude of the blade relative to the airflow or rotation plane, instantaneously changes the resultant force acting on the ice-melt water on the blade surface, such as increasing the centrifugal force or introducing a favorable aerodynamic force component, to overcome the adhesion of the ice-melt water, and to make it move from the blade surface to the blade tip or trailing edge, and finally remove it. The whole process forms a closed loop: risk evaluation guides the intervention time, pitch action performs the intervention, and removes the ice-melt water by physical means, reducing the re-freezing risk. It is this active risk intervention mechanism based on indirect information that enables the solution to effectively address the ice-melt water re-freezing problem.

[0078] In a specific embodiment, 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 time) and environmental data (such as ambient temperature, wind speed). Based on these data, the system evaluates the risk of re-freezing of the ice-melt water on the blade surface at the trailing edge of the blade and other areas through the built-in algorithm. For example, the algorithm may consider the input heating energy to estimate the amount of ice-melt water, and combine the ambient temperature and wind speed to predict the surface temperature of the trailing edge of the blade. When the estimated amount of ice-melt water reaches a certain level and the predicted trailing edge temperature is close to the freezing point, the evaluated re-freezing risk is determined to meet the set trigger condition. At this time, the control system issues an instruction to drive the blade to perform a set pitch action, such as quickly increasing the pitch angle from the current operating angle by a small angle (for example, 2 degrees) when the blade rotates to a certain azimuth angle, and then maintaining it for a short time (for example, 0.5 seconds) and then quickly recovering. The rapid change of the pitch angle produces additional centrifugal force components and aerodynamic disturbances, which throw the ice-melt water formed on the trailing edge of the blade off the blade surface, avoiding its re-freezing.

[0079] In some embodiments of the present application described above, a set pitch action is performed, which can specifically be a rapid change of the pitch angle of the blade to use the additional centrifugal force, gravity component change and aerodynamic disturbance generated thereby to promote the movement or throwing off of the ice-melt water. In this way, the ice-melt water can be removed with the help of the unit itself, however, how to accurately perform this pitch action to ensure that the ice-melt water can be effectively removed from the blade surface, especially considering the uneven distribution of ice-melt water and the complex situation of blade rotation, is still a problem to be solved.

[0080] To this end, the application further proposes to perform a set pitch action that promotes the removal of the de-icing water from the blade by changing the force acting on the de-icing water, the steps of which include:

[0081] estimating the spanwise distribution area of the de-icing water on the blade surface;

[0082] obtaining the real-time rotational azimuth angle of the blade;

[0083] determining a predetermined azimuth angle interval based on the estimated spanwise distribution area of the de-icing water on the blade surface, such that when the blade rotates and the estimated spanwise distribution area of the de-icing water is in the predetermined azimuth angle interval, the resultant force acting on the de-icing water removes it from the blade;

[0084] performing a set pitch action that promotes the removal of the de-icing water from the blade by changing the force acting on the de-icing water when the obtained real-time rotational azimuth angle of the blade is in the predetermined azimuth angle interval.

[0085] Wherein, the estimation of the spanwise distribution area of the de-icing water on the blade surface refers to the determination of the approximate position or concentration area of the de-icing water in the length direction of the blade. Various methods such as inference based on heating system operating parameters, detection based on blade surface sensors (such as humidity or temperature sensor arrays), or calculation based on blade icing / de-icing physical models can be used to achieve this purpose, which aims to obtain the position information of the de-icing water to provide a basis for subsequent determination of the favorable pitch execution time; Determining the predetermined azimuth angle interval refers to calculating or looking up a range of blade rotation angles according to the estimated de-icing water position, which can be achieved by looking up tables based on historical operating data and empirical rules, etc. The purpose is to identify the range of blade rotation angles in which the de-icing water at a specific spanwise position is most conducive to its removal from the blade surface under the combined force (including gravity, centrifugal force, aerodynamic force, and additional force generated by pitch).

[0086] The scheme of the present application intelligently selects the execution timing of the pitch action by combining the position information of the ice-melting water on the blade with the real-time rotation azimuth angle of the blade. Specifically, first, the spreadwise region where the ice-melting water is likely to gather is obtained through estimation, which lays the foundation for subsequent analysis. Then, the system monitors the current rotation azimuth angle of the blade in real time. The key is that, based on the estimated spreadwise distribution region of the ice-melting water, the system determines a predetermined azimuth angle interval, the selection of which is optimized so that when this region rotates to this angle range, the direction and size of the resultant force of various forces acting on the ice-melting water (such as the gravity component, the centrifugal force component, and the additional force generated by the pitch action) are most conducive to overcoming the adhesion of the ice-melting water, prompting it to detach from the blade surface. Finally, when the real-time rotation azimuth angle of the blade enters this predetermined favorable interval, the system immediately triggers the set pitch action. This way avoids blindly or randomly executing the pitch, but precisely acts on the ice-melting water when it is in the most easily removed position and rotation posture of the blade.

[0087] In this way, the rotation motion of the blade itself and the physical effects generated by the pitch action are effectively combined, significantly enhancing the removal efficiency of the ice-melting water, especially for the areas prone to stagnation and re-freezing. This targeted intervention can more effectively remove the ice-melting water, thereby solving the problem of ice-melting water re-freezing.

[0088] In some embodiments of the above-mentioned application, the execution of the set pitch action is proposed to change the force acting on the ice-melting water to remove it from the blade. To achieve this purpose, it is necessary to determine a predetermined azimuth angle interval so that when the blade rotates and the estimated spreadwise distribution region of the ice-melting water is in the predetermined azimuth angle interval, the resultant force acting on the ice-melting water removes it from the blade. However, in the implementation process, only the determination of the predetermined azimuth angle interval lacks comprehensive consideration of the physical properties of the blade itself, external effects during rotation, and the specific distribution state of the ice-melting water, which may result in the determined interval failing to fully utilize the most favorable mechanical conditions, affecting the removal effect of the ice-melting water. Therefore, how to comprehensively consider these factors to more accurately determine the predetermined azimuth angle interval and thus more effectively remove the ice-melting water is a technical problem to be solved.

[0089] To this end, the present application further proposes a step of determining a predetermined azimuth angle interval based on the estimated spreadwise distribution region of the ice-melting water on the blade surface, so that when the blade rotates and the estimated spreadwise distribution region of the ice-melting water is in the predetermined azimuth angle interval, the resultant force acting on the ice-melting water removes it from the blade.

[0090] Obtaining the geometric feature information of the blade;

[0091] Obtaining the fluid action information of the blade rotation process;

[0092] judging, based on the geometric feature information of the blade, the fluid action information of the blade in the rotating process, and the estimated spanwise distribution region of the de-icing water on the blade surface, which force component or combination of force components acting on the estimated spanwise distribution region of the de-icing water at different azimuth angles of the blade rotation is conducive to the removal of the de-icing water, obtaining the force component or combination of force components conducive to the removal of the de-icing water and the corresponding rotating azimuth angle;

[0093] determining a predetermined azimuth angle interval based on the force component or combination of force components conducive to the removal of the de-icing water, the corresponding rotating azimuth angle, and the estimated spanwise distribution region of the de-icing water on the blade surface.

[0094] Wherein, the geometric feature information of the blade refers to collecting the inherent physical parameters of the blade, such as chord length distribution, twist angle distribution, airfoil data, etc. These information are the basic data for analyzing the force of the de-icing water on the blade surface; the fluid action information of the blade in the rotating process refers to collecting the relevant information generated by the interaction between the blade and the air during the rotation, such as the airflow velocity and pressure distribution of a specific region on the blade surface, etc. These information are used to analyze the aerodynamic force acting on the de-icing water; judging, based on the geometric feature information of the blade, the fluid action information of the blade in the rotating process, and the estimated spanwise distribution region of the de-icing water on the blade surface, which force component or combination of force components acting on the estimated spanwise distribution region of the de-icing water at different azimuth angles of the blade rotation is conducive to the removal of the de-icing water, obtaining the force component or combination of force components conducive to the removal of the de-icing water and the corresponding rotating azimuth angle refers to, based on the geometric feature information of the blade, the fluid action information of the blade in the rotating process, and the estimated spanwise distribution region of the de-icing water on the blade surface, analyzing the size and direction of various forces (such as gravity component, centrifugal force, aerodynamic force, etc.) acting on the de-icing water in a specific spanwise distribution region at each azimuth angle of the blade from 0 to 360 degrees, and identifying which single force component or combination of multiple force components can produce an effect of promoting the de-icing water to separate from the blade surface, so as to obtain which favorable force acts at which rotating azimuth angle; determining a predetermined azimuth angle interval refers to using the favorable mechanical conditions obtained by the foregoing judging step and the azimuth angle at which they occur, and combining the estimated spanwise distribution region of the de-icing water on the blade surface, to specifically determine the best opportunity window for performing the variable pitch action.

[0095] The scheme of the present application obtains the geometric feature information of the blade and the fluid action information of the blade in the rotating process, and combines the estimated spanwise distribution region of the de-icing water on the blade surface to physically analyze the force condition of the de-icing water at different azimuth angles of the blade rotation. Thus, it can be judged that at which specific rotating azimuth angle the force component or combination of force components acting on the de-icing water is most conducive to its removal from the blade surface.

[0096] Further, based on the analysis results, one or more predetermined azimuth angle intervals can be determined accurately. When the blade rotates to these predetermined azimuth angle intervals, the pitch action is performed, which can effectively utilize or enhance the removal force acting on the deicing water, thereby facilitating the removal of the deicing water from the blade. This method based on physical analysis and condition judgment provides a scientific basis for determining the optimal timing of pitch-assisted drainage, enabling the pitch action to more effectively utilize natural forces or aerodynamic forces to remove deicing water, thereby improving the efficiency and thoroughness of deicing water removal.

[0097] In some preferred embodiments, the following can be implemented specifically:

[0098] First, the geometric feature information of the blade is obtained, such as reading the airfoil data, chord length, and twist angle distribution curves along the span from the blade design database stored in the wind turbine control system. Then, the fluid action information of the blade rotation process is obtained, which can be obtained by pre-computed fluid dynamics (CFD) simulation to obtain the surface pressure distribution and airflow velocity field of the blade at different rotation speeds and pitch angles, and these data are stored as a lookup table for querying in real-time operation according to the real-time operation state.

[0099] At the same time, the spanwise distribution area of deicing water on the blade surface is estimated according to the previous steps, such as estimating that the deicing water is mainly concentrated in a certain spanwise range of the blade trailing edge. Then, based on the obtained blade geometric feature information, fluid action information, and estimated deicing water spanwise distribution area, force analysis is performed. For example, for the estimated deicing water area, the size and direction of the gravity component, centrifugal force component, and aerodynamic force (calculated from the fluid action information) acting on the deicing water in this area at different azimuth angles during one rotation (0-360 degrees) of the blade are calculated. Determine which azimuth angles the resultant force or its component perpendicular to the blade surface points outward, or which force components (such as the centrifugal force component along the span) help the deicing water flow in the blade tip direction.

[0100] Thus, the force component or combination of force components (e.g., gravity and centrifugal force acting together) that help remove deicing water and the corresponding rotation azimuth angle (e.g., the blade is in a certain angle range of the lower region) are obtained. Finally, based on the analysis results, the predetermined azimuth angle intervals are determined, such as selecting those continuous azimuth angle ranges that are most favorable for force as the predetermined intervals.

[0101] In some embodiments of the present application, a scheme is proposed to determine a predetermined azimuth angle interval based on the estimated spread-wise distribution area of the de-icing water on the blade surface, so that when the blade rotates and the estimated spread-wise distribution area of the de-icing water is in the predetermined azimuth angle interval, the resultant force acting on the de-icing water removes it from the blade. In this way, the blade rotation position that is beneficial to the removal of de-icing water can be determined according to the characteristics of the blade and the fluid and the distribution of the de-icing water. However, in the implementation process, it is not enough to only consider the geometric characteristics of the blade, the fluid action information during the rotation of the blade, and the estimated spread-wise distribution area of the de-icing water on the blade surface, because the physical form of the de-icing water on the blade surface will directly affect its force characteristics and removal difficulty. Different physical forms of de-icing water may have different removal effects under the same force. Therefore, if the physical form of the de-icing water is ignored, the judgment of the force component or the combination of force components required to remove the de-icing water may be inaccurate, which will affect the effectiveness of the variable pitch action.

[0102] To this end, the present application further proposes a step of determining which force component or combination of force components acting on the estimated spread-wise distribution area of the de-icing water at different azimuth angles of the blade rotation is conducive to the removal of the de-icing water, obtaining the force component or combination of force components conducive to the removal of the de-icing water and the corresponding rotation azimuth angle, which includes:

[0103] Obtaining a parameter set related to the estimated spread-wise distribution area of the de-icing water on the blade surface, which can reflect the aggregation state or flow characteristics of the de-icing water;

[0104] Identifying the physical form of the de-icing water in the estimated spread-wise distribution area of the de-icing water on the blade surface according to the parameter set;

[0105] Based on the geometric characteristics of the blade, the fluid action information during the rotation of the blade, the estimated spread-wise distribution area of the de-icing water on the blade surface, and the identified physical form of the de-icing water, determining which force component or combination of force components acting on the estimated spread-wise distribution area of the de-icing water at different azimuth angles of the blade rotation is conducive to the removal of the de-icing water, obtaining the force component or combination of force components that matches the removal characteristics of the identified physical form of the de-icing water and the corresponding rotation azimuth angle.

[0106] The parameter set that can reflect the aggregation state or flow characteristics of the de-icing water refers to a group of data or indicators used to describe the amount, range, form characteristics, or motion state of the de-icing water in the distribution area on the blade surface. It can be realized by using parameters such as the estimated thickness of the de-icing water, the coverage area ratio, and the flow velocity range obtained by sensors, lookup tables, or other means. The purpose is to provide input information for subsequent identification of the specific physical form of the de-icing water;

[0107] wherein, the identifying the physical form of the ice-melting water in the span-wise distribution area of the ice-melting water on the blade surface refers to determining the specific existing form of the ice-melting water in the area according to the obtained parameter set, which can be achieved by mapping the parameter set to predefined different physical form categories (e.g., discrete water droplets, continuous water film, converging runoff, etc.) based on preset rules, lookup tables or classification algorithms, and the purpose is to identify the actual form characteristics of the ice-melting water to provide a basis for selecting a targeted removal strategy;

[0108] wherein, the force component or combination of force components and the corresponding rotation azimuth angle that match the removal characteristics of the identified physical form of the ice-melting water refers to determining the force (e.g., centrifugal force, gravity component, aerodynamic force or their combination) that is most easily removed under the identified physical form of the ice-melting water and the specific azimuth angle range of the blade rotation that can generate or enhance these forces according to the identified physical form of the ice-melting water, which can be achieved by calculating or looking up the various force components acting on the ice-melting water in different physical forms at different azimuth angles according to the physical model or empirical rules established according to the response characteristics of various forces under different physical forms, and selecting the force component combination and the corresponding azimuth angle that can generate sufficient removal effect, and the purpose is to ensure that the selected removal force and the blade position can effectively promote the removal of the ice-melting water in the current form from the blade surface.

[0109] The scheme of the present application obtains a parameter set that can reflect the aggregation state or flow characteristics of the ice-melting water, and identifies the specific physical form of the ice-melting water according to these parameters. It is because the identified physical form of the ice-melting water is used as an important basis for judging the force component or force component combination that is conducive to the removal of the ice-melting water and the corresponding rotation azimuth angle that the judgment of the favorable removal condition can more accurately match the removal needs of different ice-melting water forms.

[0110] This is because the sensitivity of ice-melting water in different physical forms to centrifugal force, aerodynamic force, gravity component and other forces and the force threshold required for removal are different. For example, thin film-like ice-melting water may be more susceptible to aerodynamic force and centrifugal force, while discrete water droplets may be more sensitive to gravity component and inertial force generated by rapid pitch change.

[0111] By identifying the specific form, the scheme can selectively or combinatorially select the most effective force component, and determine the azimuth angle of the blade rotation that can 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 the ice-melting water into the decision-making process is an improvement over the existing judgment logic, making the removal strategy more targeted.

[0112] In some specific embodiments, a parameter set related to the estimated ice-melt water distribution area on the blade surface and capable of reflecting the ice-melt water aggregation state or flow characteristics is obtained, which can be specifically obtained by obtaining the operating parameters of the wind turbine generator set, environmental data, and pre-stored information related to the formation and evolution of ice-melt water on the blade surface, inferring the estimated thickness, coverage area ratio, and flow velocity range of the ice-melt water in the estimated ice-melt water distribution area on the blade surface based on these information, and taking these inferred parameters as the parameter set.

[0113] According to the parameter set, for example, according to the combination of the estimated thickness, coverage area ratio, and flow velocity range, the physical form of the ice-melt water in the estimated ice-melt water distribution area on the blade surface is identified, for example, it is judged whether it is in the form of a film, a water droplet, or a converging runoff. Based on the geometric feature information of the blade, the fluid action information during the rotation of the blade, the estimated ice-melt water distribution area on the blade surface, and the identified physical form of the ice-melt water, for example, if the ice-melt water is identified as a film, the system will focus on analyzing which azimuth angle the centrifugal force or the aerodynamic force has the strongest removal effect on the film; if it is identified as a water droplet, it may focus more on which azimuth angle the gravity component or the inertial force generated by the rapid pitch has a more effective effect on the water droplet.

[0114] Through such analysis and judgment, the force component or the combination of force components that match the removal characteristics of the identified physical form of the ice-melt water and the corresponding rotation azimuth angle are obtained.

[0115] In some embodiments of the present application, a parameter set related to the estimated ice-melt water distribution area on the blade surface and capable of reflecting the ice-melt water aggregation state or flow characteristics is obtained, which can be specifically obtained by a simple empirical model, for example, according to the total heating time and average power of the blade heating system, and combining the environmental temperature to estimate the total ice-melt water amount generated on the blade surface, and taking the total water amount as a parameter, so that the overall scale of the ice-melt water can be preliminarily understood. However, in the implementation process, only the parameter set related to the estimated ice-melt water distribution area on the blade surface and capable of reflecting the ice-melt water aggregation state or flow characteristics is obtained, and the detailed state of the ice-melt water in a specific area (such as local thickness, coverage range, and flow velocity) is not evaluated, which may lead to inaccurate identification of the physical form of the ice-melt water, and cannot fully reflect the true state of the ice-melt water on the blade surface, especially in the easy refreezing area, so that the subsequent pitch action may not be able to solve the local refreezing problem, affecting the deicing effect.

[0116] To this end, the present application further proposes a step of obtaining a parameter set related to the estimated ice-melt water distribution area on the blade surface and capable of reflecting the ice-melt water aggregation state or flow characteristics, which includes:

[0117] obtaining an operating parameter of the wind turbine generator set;

[0118] obtaining environmental data;

[0119] obtaining pre-stored associated information of formation and evolution rules of the ice-melting water on the blade surface;

[0120] based on the obtained operating parameter of the wind turbine generator set, the obtained environmental data, and the obtained pre-stored associated information of the formation and evolution rules of the ice-melting water on the blade surface, inferring an estimated thickness, a coverage area ratio, and a flow velocity range of the ice-melting water in a spanwise distribution area of the ice-melting water on the blade surface;

[0121] using the inferred estimated thickness, coverage area ratio, and flow velocity range as a parameter set related to the spanwise distribution area of the ice-melting water on the blade surface, which can reflect the aggregation state or flow characteristics of the ice-melting water.

[0122] The pre-stored associated information of the formation and evolution rules of the ice-melting water on the blade surface refers to the establishment of priori knowledge or experience models of the thickness, coverage, and flow trend of the ice-melting water on the blade surface under different combinations of operating parameters and environmental data. The pre-stored associated information can be implemented by using a rule set, a lookup table, or a machine learning model stored in a database. The purpose is to provide logical rules or reference benchmarks for inference based on current data.

[0123] The estimated thickness refers to an estimated value of the average or maximum water layer thickness in a specific spanwise distribution area of the ice-melting water on the blade surface. The estimated thickness can be calculated based on ice-melting water quantity estimation and distribution models. The purpose is to represent the aggregation degree of the ice-melting water.

[0124] The coverage area ratio refers to the proportion of the area covered by the ice-melting water in a specific spanwise distribution area of the ice-melting water on the blade surface to the total area of the region. The coverage area ratio can be calculated based on ice-melting water quantity estimation and surface spreading models. The purpose is to represent the distribution breadth of the ice-melting water.

[0125] The flow velocity range refers to an estimated interval of the flow velocity of the ice-melting water in a specific spanwise distribution area of the ice-melting water on the blade surface. The flow velocity range can be calculated based on blade force (gravity, centrifugal force, aerodynamic force) analysis and fluid dynamics models. The purpose is to represent the flow characteristics of the ice-melting water.

[0126] The parameter set refers to a data set formed by combining the inferred estimated thickness, coverage area ratio, and flow velocity range. The parameter set can be implemented by using a vector or structure containing three numerical values. The purpose is to provide effective and quantitative input for subsequent ice-melting water physical form identification.

[0127] The scheme of the present application obtains the operating parameters of the wind turbine, environmental data, and pre-stored associated information of the formation and evolution rules of the ice-melting water on the blade surface, and based on these information, infers the estimated thickness, coverage area ratio and flow velocity range of the ice-melting water in the estimated spanwise distribution area of the ice-melting water on the blade surface. Finally, these inferred parameters are used as a parameter set reflecting the ice-melting water accumulation state or flow characteristics.

[0128] This way makes use of the existing operating data and external environmental information of the wind turbine itself, combined with the pre-established ice-melting water behavior rule model, to realize indirect and non-intrusive evaluation of the key physical characteristics of the ice-melting water on the blade surface. By inferring the three specific parameters of the estimated thickness, coverage area ratio and flow velocity range, this scheme can more finely depict the state of the ice-melting water in a specific area, rather than just a total water amount or a simple existence or non-existence judgment. These more descriptive parameter sets provide a richer and more accurate basis for subsequent identification of the physical form of the ice-melting water (for example, is it a thin water film, local water accumulation or a flowing droplet flow).

[0129] Compared with the scheme that only relies on the total water amount or simple judgment, the parameter set provided by this scheme can more effectively support the differentiation of the physical form of the ice-melting water, so that the pitch action based on the identification result can more accurately target the removal characteristics of different forms of ice-melting water, improving the efficiency and thoroughness of ice-melting water removal, especially when dealing with ice-melting water in areas prone to retention and re-freezing. This method of inferring key parameters and constructing parameter sets through indirect information avoids the cost and maintenance burden of installing additional sensors on the blade surface, providing a practical and economical parameter acquisition approach, and laying a solid foundation for subsequent ice-melting water physical form identification and pitch-assisted drainage strategies.

[0130] In some preferred embodiments, specifically, the current power of the blade heating system, the accumulated heating time length, the current pitch angle of the blade and the rotor speed can be acquired as the operating parameters of the wind turbine generator set. Meanwhile, the system acquires the ambient temperature, humidity and wind speed from the weather station or the nacelle sensors as the environmental data. In addition, the system loads the pre-stored associated information, such as a lookup table or a model established based on historical data and simulation, which describes the thickness, coverage ratio and flow velocity range of the ice-melting water that can be reached in a specific spanwise region of the blade trailing edge under different heating states, environmental conditions and blade attitudes. Based on the acquired operating parameters, environmental data and pre-stored associated information, the system makes an inference. For example, if the heating power is high, the accumulated time length is long, the ambient temperature is close to the freezing point and the wind speed is high, and the blade trailing edge region is identified as an area prone to water accumulation, the system can infer that the estimated thickness of this region is in a certain millimeter range, the coverage area ratio reaches a certain percentage, and the flow velocity range is in a certain meter per second interval due to the effects of air flow and gravity. The system packages the inferred estimated thickness, coverage area ratio and flow velocity range values into a parameter set for subsequent steps.

[0131] In some embodiments of the present application described above, the re-freezing risk of the ice-melting water generated on the blade surface is evaluated based on the operating parameters and environmental data to obtain the evaluated re-freezing risk. The evaluation of the re-freezing risk can be specifically achieved by monitoring the total heating energy of the blade heating system and combining the ambient temperature, for example, when the total heating energy reaches a preset threshold and the ambient temperature is below the freezing point, it is determined that there is a re-freezing risk. In this way, a preliminary judgment of the re-freezing risk can be made. However, in the implementation process, only the overall operating parameters and environmental data are relied on, and the quantitative estimation of the amount of ice-melting water and the consideration of the local characteristics of the blade surface are lacking, which may not accurately and effectively evaluate the re-freezing risk, especially without relying on a large number of additional sensors, resulting in inaccurate evaluation results and difficulty in effectively guiding the subsequent pitch action, thereby affecting the overall de-icing effect.

[0132] To this end, the present application further proposes a step of evaluating the re-freezing risk of the ice-melting water generated on the blade surface, which includes:

[0133] estimating the amount of ice-melting water formed on the blade surface based on the operating parameters and the pre-set physical characteristic parameters;

[0134] identifying specific regions on the blade that are prone to water accumulation or surface temperature reduction due to geometric structure or air flow as key regions for risk evaluation;

[0135] analyzing the current surface temperature state of the key regions based on the operating parameters, the environmental data and the characteristics of the identified key regions;

[0136] Based on the operating parameters, environmental data, and in combination with the estimated ice-melt water amount and the current surface temperature state of the analyzed key area, the re-freezing risk of the ice-melt water generated on the blade surface in the key area is evaluated to obtain an evaluated re-freezing risk.

[0137] The preset physical property parameters refer to parameters related to the physical properties of ice and water and energy conversion processes that need to be used when estimating the ice-melt water amount, which can include the latent heat of ice melting, 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 materials during the system design phase.

[0138] The specific areas on the blade where ice-melt water is prone to accumulate or the surface temperature is prone to decrease due to geometric structure or airflow effects refer to areas on the blade surface where ice-melt water is prone to accumulate, flow slowly, or even stagnate due to their own shape characteristics (such as grooves, edges, complex curves), or where local heat exchange is enhanced and the surface temperature is more prone to drop below freezing due to the airflow effects caused by blade rotation, which can include the trailing edge of the blade, the wingtip portion, certain chordwise positions, etc.

[0139] The key areas for risk evaluation refer to the specific areas identified above that are prone to accumulate ice-melt water or prone to temperature decrease, which are the focus of attention and analysis when evaluating the re-freezing risk of ice-melt water.

[0140] The characteristics of the identified key areas refer to physical properties or state information related to the key areas identified above, which can include the geometric shape, material properties, orientation relative to the airflow, coverage of the heating system, etc. These characteristics can affect the flow and thermodynamic state of ice-melt water in the area.

[0141] The current surface temperature state of the key area refers to the surface temperature or temperature change trend of the key area identified above at the current time, which can be obtained by combining operating parameters, environmental data, and the characteristics of the key area to calculate, estimate, or infer.

[0142] The estimated ice-melt water amount refers to the total amount of ice-melt water formed on the blade surface or the ice-melt water amount in a local area, which is calculated or inferred by analyzing the operating parameters of the blade heating system and combining the preset physical property parameters.

[0143] The scheme of the present application refines the evaluation process of the re-freezing risk into multiple interrelated steps, achieving a fine judgment of the risk.

[0144] Firstly, by analyzing the operating parameters of the blade heating process and combining the preset physical characteristic parameters, the amount of ice-melting water generated on the blade surface can be quantitatively estimated, which provides a quantitative basis for the amount of potential icing substances for risk assessment.

[0145] Then, the scheme identifies specific areas on the blade that are naturally high-risk due to geometric structure or airflow influence, focusing the evaluation on these key areas, improving the targeting of the evaluation. On this basis, combined with operating parameters, environmental data, and the characteristics of these key areas themselves, the current surface temperature state of these high-risk areas is analyzed to obtain direct information on whether the ice-melting water has re-freezing temperature conditions.

[0146] Finally, the estimated ice-melting water amount, temperature state of key areas, and operating parameters, environmental data, and other information are integrated to evaluate the likelihood of re-freezing of ice-melting water in these key areas. This step-by-step, focused, and quantitative evaluation method, compared to the rough judgment method based on overall parameters, can more accurately capture the key factors of local re-freezing occurrence, resulting in a more accurate re-icing risk assessment result. This accurate assessment result can effectively guide the subsequent decision of whether to trigger the pitch action, improving the accuracy and effectiveness of the entire pre-control method.

[0147] In some preferred embodiments, the present application is implemented as follows:

[0148] During the blade heating de-icing process of a wind turbine generator set, the control system performs the step of evaluating the re-freezing risk of ice-melting water generated on the blade surface. Specifically, the system first estimates the amount of ice-melting water formed on the blade surface based on the operating parameters of the blade heating system, such as recording the cumulative heating time and average heating power of each heating area, and combining preset physical characteristic parameters, such as the latent heat of ice melting and empirical efficiency coefficient.

[0149] For example, if the blade leading edge main heating area is heated for 30 minutes with an average power of 2kW, and the trailing edge auxiliary heating area is heated for 20 minutes with an average power of 0.8kW, using the latent heat of ice melting of 334 kJ / kg and the empirical coefficient of 0.7, the total ice-melting water amount can be estimated to be about 9.7 kg.

[0150] Meanwhile, the system identifies specific regions on the blade where ice-melt water is prone to stay or surface temperature is prone to decrease due to geometric configuration or air flow effect, such as the trailing edge and tip portion of the blade, and takes these regions as key regions for risk assessment. Then, the system analyzes the current surface temperature state of these key regions based on current operating parameters (such as blade rotational speed, pitch angle), environmental data (such as ambient temperature -5℃, wind speed 12m / s), and the characteristics of the identified key regions (such as the geometry and material of the trailing edge), for example, by estimating the surface temperature of the trailing edge region through a simplified heat balance model or a lookup table method.

[0151] Finally, the system comprehensively assesses the re-freezing risk of the ice-melt water generated on the blade surface in the key regions based on the current operating parameters, environmental data, and in combination with the estimated ice-melt water amount (e.g. 9.7 kg) and the analyzed current surface temperature state of the key regions (e.g. the trailing edge region temperature is close to freezing point). For example, if the estimated water amount is large and the temperature of the key region is close to or below freezing point, the re-freezing risk is assessed as high.

[0152] In some embodiments of the above-mentioned application, the re-freezing risk of the ice-melt water generated on the blade surface in the blade is assessed based on operating parameters and environmental data, and the assessed re-freezing risk is used to identify the risk of re-freezing of the ice-melt water. However, relying solely on the assessment result of the re-freezing risk may not be sufficient to guide effective de-icing strategies. For example, at a specific stage of the heating process or when the amount of ice-melt water is small, even if there is a certain re-freezing risk, it may not be necessary to immediately take pitch action, or the pitch action needs to be optimized according to the real-time rotational azimuth angle of the blade to achieve better drainage effect. Therefore, how to comprehensively consider the amount of ice-melt water, the heating stage, the re-freezing risk, and the azimuth angle of the blade, and more accurately trigger and adjust the pitch action, is a problem to be solved by the present application.

[0153] To this end, the application further proposes a method comprising:

[0154] obtaining an estimated total ice-melt water amount on the blade surface, stage information of the current heating process, and a real-time rotational azimuth angle of the blade;

[0155] based on the obtained estimated total ice-melt water amount on the blade surface, stage information of the current heating process, the assessed re-freezing risk, and the obtained real-time rotational azimuth angle of the blade, determining whether a preset pitch-assisted drainage triggering condition combination is met;

[0156] if it is determined that the pitch-assisted drainage triggering condition combination is met, determining the amplitude, rate, and mode of the pitch action based on the obtained real-time rotational azimuth angle of the blade and a preset drainage efficiency adjustment logic;

[0157] executing the determined pitch action.

[0158] The estimated total ice-melt water amount on the blade surface refers to the total ice-melt water amount information on the blade surface obtained by calculation or inference, which can be achieved by estimating based on the operating parameters of the heating system, and the purpose is to provide a quantitative basis for determining whether there is enough ice-melt water on the current blade to be effectively removed by the pitch action.

[0159] The stage information of the current heating process refers to the information reflecting the progress state of the blade heating deicing process, which can be represented in the form of heating time, estimated remaining heating time, or heating power change curve, and the purpose is to evaluate the sufficiency of the ice-melt process and ensure that the pitch drainage operation is performed in a favorable time window.

[0160] The preset combination of pitch-assisted drainage triggering conditions refers to a set of logical judgment rules composed of multiple specific conditions, which can be realized by logic gate circuits or software judgment statements, and the purpose is to achieve accurate control of the starting time of pitch-assisted drainage through multi-factor comprehensive judgment.

[0161] The preset drainage efficiency adjustment logic refers to the established rules or calculation methods aimed at maximizing the ice-melt water removal effect, which can be realized by lookup table method, calculation based on physical model, or machine learning model, and the purpose is to output the optimal pitch control parameters according to the input real-time working condition information.

[0162] The scheme of the present application further obtains the total ice-melt water amount 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 evaluation of the refreezing risk. It is precisely because these multi-dimensional real-time working condition inputs are obtained that the subsequent drainage decision and parameter configuration have a more comprehensive information basis.

[0163] Based on the estimated total ice-melt water amount on the blade surface, the stage information of the current heating process, the evaluated refreezing risk, and the obtained real-time rotation azimuth angle of the blade, the system comprehensively judges whether the preset combination of pitch-assisted drainage triggering 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 key moment when the ice-melt water amount is appropriate, the heating stage is suitable, the refreezing risk exists, and the blade posture is conducive to drainage, thereby avoiding ineffective or inappropriate pitch operations.

[0164] On this basis, if it is judged that the triggering condition is met, the specific amplitude, rate and mode of the variable pitch action are further determined dynamically based on the acquired real-time rotational azimuth angle of the blade and the preset drainage efficiency adjustment logic. It is precisely because the variable pitch parameters are dynamically adjusted according to the real-time azimuth angle and the preset logic that the variable pitch action can utilize or enhance the removal force acting on the deicing water in a specific blade posture, so as to produce the most beneficial mechanical effect for the removal of deicing water under specific conditions, thereby maximizing the drainage effect.

[0165] Finally, the determined variable pitch action is executed to convert the entire pre-control strategy into actual physical intervention, which changes the force acting on the deicing water to promote it to separate from the blade surface, so as to achieve the purpose of inhibiting or removing secondary ice formation. This strategy of combining multi-dimensional real-time information with re-freezing risk assessment and dynamically optimizing variable pitch parameters, compared with the way of relying only on a single risk threshold to trigger a fixed action, realizes more refined and scene-adaptive control, and improves the effectiveness of deicing water removal.

[0166] In some preferred embodiments, the present application is implemented as follows:

[0167] Suppose that during the blade heating deicing process, the system has evaluated the re-freezing risk to be high based on operating parameters and environmental data. At this time, the system acquires the estimated total deicing water amount on the blade surface, for example, the estimated value is 9.7 kg. At the same time, the stage information of the current heating process is acquired, for example, the heating has lasted for 70% of the total planned time. The system also acquires the real-time rotational azimuth angle of the blade, for example, the current is 3 o'clock azimuth. Based on the acquired 9.7 kg deicing water amount, 70% heating stage information, high re-freezing risk evaluation result and 3 o'clock real-time rotational azimuth angle, the system judges whether the preset variable pitch auxiliary drainage triggering condition combination is met.

[0168] The combination of conditions can be set as: the amount of ice-melting water is greater than 5 kg, and the heating stage is between 50% and 90% of the total time, and the refreezing risk is medium or high, and the blade azimuth angle is in a predetermined interval that is beneficial to drainage, for example, 6 o'clock to 8 o'clock azimuth. Assuming that the current azimuth angle is 3 o'clock, the azimuth angle condition is not met, and 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, the system determines the amplitude, rate and mode of the variable pitch action based on the acquired 7 o'clock blade real-time rotating azimuth angle and the preset drainage efficiency adjustment logic. The preset logic can determine that the gravitational component is beneficial to drainage at this time according to the 7 o'clock azimuth, and thus determine to perform a variable pitch action of rapidly increasing the pitch angle (towards feathering) once, for example, from the current operating pitch angle 2° to 4°, the rate adopts the maximum rate allowed by the system, and the mode is single rapid shaking. Subsequently, the system executes the determined variable pitch action to control the variable pitch actuator to rapidly change the blade pitch angle from 2° to 4° and quickly restore it to 2°. This action utilizes the gravitational component and the additional force generated by the variable pitch to promote the ice-melting water on the blade surface to be thrown away.

[0169] In some embodiments of the present application described above, the ice-melting water on the blade surface is removed by a variable pitch action. Specifically, when the refreezing risk of the ice-melting water is evaluated to meet the set trigger condition, a set variable pitch action is performed, which promotes the ice-melting water on the blade surface to be removed by changing the force acting on the ice-melting water, thereby reducing the risk of refreezing of the ice-melting water. However, in the process of its implementation, due to the uneven distribution of ice-melting water, the complex structure of the blade surface, and the possible execution error of the variable pitch action itself, relying only on the preset variable pitch parameters may not be able to ensure that the ice-melting water is fully removed. In addition, due to the lack of real-time feedback on the removal effect of the ice-melting water, the control system is difficult to judge whether the current variable pitch action is effective and whether it needs to be adjusted or supplemented, which may result in the residual of part of the ice-melting water and increase the risk of refreezing.

[0170] To this end, the present application further proposes that the step of executing the determined variable pitch action comprises:

[0171] In the step of executing the determined variable pitch action, the operating parameters of the driving mechanism driving the blade to perform the variable pitch are monitored to obtain monitored driving mechanism operating parameters;

[0172] The monitored driving mechanism operating parameters or a feature quantity calculated based on the monitored driving mechanism operating parameters are compared with a preset driving mechanism operating parameter benchmark representing the same type of variable pitch action performed by the blade in an ice-melting water removed state to obtain a comparison result;

[0173] If the comparison result indicates that the ice melt water separation is insufficient, a supplementary pitching action is performed or the parameters of a subsequent pitching action are adjusted to facilitate the removal of the ice melt water.

[0174] Among them, monitoring the operating parameters of the drive mechanism that drives the blades to change pitch refers to obtaining the working status data of the power component responsible for changing the blade pitch angle in the wind turbine during the pitch change action. This can be achieved by monitoring the drive current, drive voltage, power consumption, output torque or hydraulic system pressure of the pitch motor or hydraulic system. Its purpose is to obtain real-time information reflecting the load status of the drive mechanism;

[0175] The monitored operating parameters of the drive mechanism refer to the original working status data of the drive mechanism obtained through monitoring. They can be realized by using numerical values ​​or time series obtained by devices such as current sensors, voltage sensors, power meters, torque sensors or pressure sensors. Their purpose is to provide direct data for subsequent analysis and comparison;

[0176] The characteristic quantity calculated based on the monitored operating parameters of the drive mechanism refers to a specific indicator extracted from the original monitoring data that can more significantly or stably reflect the change in the load of the drive mechanism. It can be achieved by calculating the peak value, average value, integral value over a period of time, and change rate of the operating parameters during the pitch change process. Its purpose is to enhance the sensitivity to blade load changes and the accuracy of comparison;

[0177] The preset operating parameter benchmark of the drive mechanism, which characterizes the blades performing the same type of pitching action with melted ice water removed, refers to a predetermined range of normal operating parameters or typical values ​​representing the drive mechanism performing the same pitching action when there is no melted ice water attached to the blade surface or the melted ice water has been fully removed. The benchmark can be established and obtained by analyzing historical operating data, performing theoretical modeling calculations, or performing calibration tests under clean blade conditions. Its purpose is to provide a reference standard for evaluating the current melted ice water removal status.

[0178] The comparison result indicating insufficient meltwater removal is a conclusion reached by comparing the currently monitored operating parameters or characteristic quantities of the drive mechanism with a preset benchmark. This conclusion indicates that the current pitch control action has failed to effectively remove the meltwater from the blade surface. This conclusion can be achieved by determining whether the difference between the monitored value and the benchmark exceeds a preset threshold, etc., with the purpose of providing a decision basis for whether further intervention measures are needed.

[0179] The supplementary pitch action refers to one or more pitch action sequences performed after the original pitch action sequence is completed, for further removing residual ice-melting water. The supplementary pitch action can be implemented by performing one or more additional pitch action sequences aimed at removing residual ice-melting water. The purpose of the supplementary pitch action is to remedy the ice-melting water that has not been sufficiently removed.

[0180] Adjusting the parameters of the subsequent pitch action refers to modifying the parameters of the pitch action that is planned to be performed subsequently, according to the evaluation result of the current ice-melting water removal effect. The adjustment can be implemented by increasing the amplitude, speed, duration of the pitch action, or changing the specific action mode. The purpose of the adjustment is to improve the efficiency of the subsequent pitch action in removing ice-melting water.

[0181] The scheme of the present application can monitor the operating parameters of the driving mechanism that drives the pitch of the blade in real time when performing the pitch action aimed at throwing off the ice-melting water. These parameters can indirectly reflect the load state of the blade surface, including the attachment of ice-melting water. Comparing these monitored parameters or feature quantities calculated based thereon with the preset driving mechanism operating parameter baseline representing the clean state of the blade, the effect of the current pitch action on throwing off the ice-melting water can be quantitatively evaluated. Due to this indirect evaluation mechanism based on the operating information of the driving mechanism itself, the system can determine whether the ice-melting water has been sufficiently removed without relying on additional sensors on the blade surface. Further, if the comparison result indicates that the ice-melting water has not been sufficiently thrown off, the system can automatically trigger a supplementary pitch action or adjust the parameters of the subsequent pitch action based on this feedback information. This closed-loop feedback adjustment based on the effect evaluation enables the ice-melting water removal process to have the ability of self-correction and optimization. Compared with the open-loop control that only executes the preset program, the present scheme significantly improves the thoroughness and success rate of ice-melting water removal by introducing real-time evaluation of the throwing-off effect and adaptive intervention based on the evaluation result. This method, combined with the technical means of removing ice-melting water by pitch action in the prior scheme, forms a more intelligent and robust ice-melting water management strategy, which can more effectively deal with the ice-melting water refreezing problem and ensure that the blade truly returns to a safe operating state after heating and deicing.

[0182] In some embodiments of the present application, after the combination of the triggering conditions of the auxiliary drainage of the variable pitch is met, the amplitude, rate and mode of the variable pitch action are determined based on the acquired real-time rotating azimuth angle of the blade and the preset drainage efficiency adjustment logic, and the determined variable pitch action is executed. The execution of the determined variable pitch action can be specifically controlling the blade pitch angle to change in a small range and at a high variable pitch rate based on the current operating pitch angle, for example, increasing or decreasing a few degrees. In this way, the additional centrifugal force component change and the instantaneous aerodynamic disturbance generated by the variable pitch can be used to promote the removal of the ice melting water from the blade. However, during the implementation process, the distribution of the ice melting water on the surface of the blade is uneven, especially in the spanwise direction of the blade. The ice melting water may be concentrated in certain areas. If the variable pitch action is simply executed, the various forces (such as gravity and centrifugal force) during the rotation of the blade may not be fully utilized to enhance the removal effect of the ice melting water, resulting in a decrease in the efficiency of the variable pitch action, and even multiple variable pitches are required to achieve the ideal de-icing effect, thereby increasing the energy consumption and the burden on the actuator.

[0183] To this end, the present application further proposes that the step of executing the determined variable pitch action comprises:

[0184] estimating the concentrated distribution area of the ice melting water in the spanwise direction of the blade based on parameters related to the blade heating process or historical icing information of the blade;

[0185] acquiring the real-time rotating azimuth angle of the blade;

[0186] determining at least one predetermined rotating azimuth angle interval according to the estimated concentrated distribution area of the ice melting water in the spanwise direction of the blade and the change characteristics of the force acting on the concentrated distribution area during the rotation of the blade, the selection of the predetermined rotating azimuth angle interval being to execute the determined variable pitch action when the estimated concentrated distribution area of the ice melting water is in the interval, so as to utilize or enhance the removal force acting on the ice melting water;

[0187] when the acquired real-time rotating azimuth angle of the blade enters the at least one predetermined rotating azimuth angle interval, executing the determined variable pitch action.

[0188] In the present application, the estimation of the concentrated distribution area of the ice melting water in the spanwise direction of the blade based on parameters related to the blade heating process or historical icing information of the blade means that the position where the ice melting water may be concentrated in the length direction of the blade is predicted by analyzing the operating data of the blade heating system or the performance of the blade in past icing events. This can be achieved by analyzing parameters such as the heating power and heating time of each heating area, or by consulting historical icing frequency and thickness records of specific blade areas. The purpose is to obtain the position information where the ice melting water may be concentrated in the length direction of the blade;

[0189] The blade icing history information refers to recorded data about the characteristics of the ice layer formed on the blade in previous icing events, the distribution position, melting and shedding, etc., which can be obtained and stored by means of sensor recording, image analysis or manual inspection recording, and the purpose thereof is to provide historical data basis for estimating the concentrated distribution area of the ice-melting water in the blade span direction;

[0190] The concentrated distribution area in the blade span direction refers to a specific area in the length direction of the blade where the ice-melting water is prone to collect, stay or flow slowly due to the influence of factors such as gravity, centrifugal force, airflow or blade geometry, which can be one or more span positions or ranges, and the purpose thereof is to determine the position where the ice-melting water is likely to exist in a large amount, thereby providing targeted information for subsequent optimization of the execution time of the variable pitch.

[0191] The change characteristics of the force acting on the concentrated distribution area during the rotation of the blade refer to the variation law of the size and direction of the combined force of gravity, centrifugal force, aerodynamic force, etc. acting on the specific area in the blade span direction with the change of the blade rotation azimuth angle during the rotation of the blade with the hub, which can be obtained by means of physical modeling, simulation calculation or empirical data analysis, and the purpose thereof is to identify at which rotation azimuth angles the removal of the ice-melting water is most significant.

[0192] The at least one predetermined rotation azimuth angle interval refers to one or more angle ranges determined in advance in the rotation plane of the blade, and when the real-time rotation azimuth angle of the blade falls within these intervals, it is considered to be a favorable opportunity to execute the variable pitch action to promote the removal of the ice-melting water, which can be calculated or looked up according to the estimated ice-melting water concentrated distribution area and the change characteristics of the force, and the purpose thereof is to plan the best time window for executing the variable pitch action.

[0193] The selection of the predetermined rotation azimuth angle interval, which aims to utilize or enhance the removal force acting on the ice-melting water when the estimated ice-melting water concentrated distribution area is in the interval, refers to the principle followed when determining the above-mentioned predetermined rotation azimuth angle interval, that is, the selected interval should enable the natural forces (such as gravity and centrifugal force) generated by the rotation of the blade to act in cooperation with the forces generated by the variable pitch action, or make the variable pitch action itself have a better effect on the ice-melting water at these azimuth angles, which can be selected by means of an optimization algorithm or based on empirical rules, and the purpose thereof is to ensure that the variable pitch action occurs at the most favorable time for the removal of the ice-melting water.

[0194] The scheme of the present application further optimizes the execution time of the variable pitch action by evaluating the risk of re-freezing of the ice-melting water during the blade heating and de-icing process of the wind turbine generator set, and determining and executing the variable pitch action to promote the removal of the ice-melting water when the risk meets the triggering condition.

[0195] Specifically, the scheme first estimates the region where the de-icing water is likely to concentrate on the blade spanwise according to the parameters related to the blade heating process or the blade icing history information. Meanwhile, the system continuously acquires the real-time rotation azimuth angle of the blade. When the variable pitch action needs to be performed, the scheme does not immediately perform the variable pitch action, but determines one or more predetermined rotation azimuth angle intervals according to the estimated de-icing water concentration distribution region and the force change characteristics, such as gravity component, centrifugal force, acting on the region during the rotation of the blade. The selection target of these intervals is to perform the variable pitch action when the estimated de-icing water concentration region is in these intervals, so as to utilize the natural force generated by the rotation of the blade or enhance the removal effect of the de-icing water by the variable pitch action itself. Finally, when the acquired real-time rotation azimuth angle of the blade enters these predetermined intervals, the system triggers the execution of the previously determined variable pitch action. In this way, the execution of the variable pitch action is combined with the favorable posture of the blade rotation, so that the variable pitch action can act on the position where the de-icing water is most likely to concentrate, and occurs at the most favorable moment for its removal, thereby improving the de-icing water removal amount of a single variable pitch operation and enhancing the overall de-icing water removal efficiency.

[0196] In a second aspect, referring to Figure 2 The application further provides a wind turbine blade icing pre-control system, which comprises:

[0197] The acquisition module 210 is configured to acquire the operating parameters and environmental data of the wind turbine during the blade heating de-icing process.

[0198] The evaluation module 220 is configured to evaluate the re-freezing risk of the de-icing water generated on the blade surface based on the operating parameters and environmental data, and obtain the evaluated re-freezing risk.

[0199] The control module 230 is configured to control the wind turbine to perform the set variable pitch action when the evaluated re-freezing risk meets the set triggering condition, so as to change the force acting on the de-icing water and promote the removal of the de-icing water from the blade.

[0200] By evaluating the re-freezing risk of the de-icing water and performing the variable pitch action when the risk meets the condition, the force acting on the de-icing water is changed by the variable pitch to promote the removal of the de-icing water, thereby reducing or avoiding re-freezing, which has the advantages of effectively reducing or avoiding the re-freezing risk of the de-icing water on the blade surface, improving the de-icing effect, and ensuring the safety of the unit.

[0201] In addition, in some preferred embodiments, the wind turbine blade icing pre-control system provided by the application can perform any one step of the above method.

[0202] The above merely provides an example of the present application, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A wind turbine blade ice pre-control method, characterized in that: include: Obtain operating parameters and environmental data of wind turbines during blade heating and de-icing; Based on the operating parameters and the environmental data, evaluating the refreezing risk of the melted ice water generated on the blade surface on the blade to obtain an evaluated refreezing risk; When the assessed refreezing risk meets a set trigger condition, a set pitch change action is executed, wherein the set pitch change action causes the melted ice water to be removed from the blade by changing the force acting on the melted ice water; The step of executing a set pitch change action, wherein the set pitch change action causes the melted ice water to be removed from the blade by changing the force acting on the melted ice water, includes: estimating a spanwise distribution area of ​​the ice melt water on the blade surface; Acquiring the real-time rotation azimuth angle of the blade; determining a predetermined azimuth angle interval based on the estimated spanwise distribution area of ​​the meltwater on the blade surface, such that when the blade rotates and the estimated spanwise distribution area of ​​the meltwater is within the predetermined azimuth angle interval, a resultant force acting on the meltwater causes the meltwater to be removed from the blade; When the real-time rotation azimuth angle of the blade is within the predetermined azimuth angle range, the set pitch change action is executed to change the force acting on the ice-melting water so as to remove the ice-melting water from the blade; The step of evaluating the refreezing risk of the meltwater generated on the blade surface on the blade based on the operating parameters and the environmental data, and obtaining the evaluated refreezing risk includes: estimating the amount of ice melt water formed on the blade surface based on the operating parameters and preset physical characteristic parameters; Identify specific areas on the blade where meltwater is likely to be retained or where the surface temperature is likely to be reduced due to geometric structure or airflow, as key areas for risk assessment; analyzing a current surface temperature state of the key area based on the operating parameters, the environmental data, and the characteristics of the identified key area; Based on the operating parameters, the environmental data, and in combination with the estimated amount of meltwater and the analyzed current surface temperature state of the key area, the refreezing risk of the meltwater generated on the blade surface in the key area is evaluated to obtain the evaluated refreezing risk.

2. The wind turbine blade ice pre-control method according to claim 1, characterized in that: The step of determining a predetermined azimuth angle interval based on the estimated spanwise distribution area of ​​the melted ice water on the blade surface, so 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 the melted ice water to be removed from the blade includes: Obtaining geometric feature information of the blade; Obtain fluid action information during blade rotation; Based on the geometric characteristic 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, determining 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 removing the melted ice water, and obtaining the force component or combination of force components conducive to removing the melted ice water and the corresponding rotation azimuth angle; The predetermined azimuth angle interval is determined based on the force component or combination of force components that facilitates the removal of the de-icing water, the corresponding rotational azimuth angle, and the estimated spanwise distribution area of ​​the de-icing water on the blade surface.

3. The wind turbine blade ice pre-control method according to claim 2, characterized in that: The step of determining, 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, 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 conducive to the removal of the melted ice water and the corresponding rotation azimuth angle includes: Acquire 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; identifying the physical form of the estimated meltwater within a spanwise distribution area of ​​the blade surface based on the parameter set; Based on the geometric feature information of the blade, the fluid action information during the blade rotation process, the estimated spanwise distribution area of ​​the meltwater on the blade surface, and the identified physical form of the meltwater, it is determined which force component or combination of force components acting on the estimated spanwise distribution area of ​​the meltwater at different azimuth angles of blade rotation is conducive to removing the meltwater, and the force component or combination of force components that matches the removal characteristics of the identified physical form of the meltwater and the corresponding rotation azimuth are obtained.

4. The wind turbine blade ice pre-control method according to claim 3, characterized in that: The step of obtaining a parameter set related to the estimated spanwise distribution area of ​​the melted ice water on the blade surface and capable of reflecting the aggregation state or flow characteristics of the melted ice water includes: Obtaining operating parameters of wind turbines; Obtain environmental data; Obtaining the correlation information of the formation and evolution of pre-stored ice melt water on the leaf surface; Inferring an estimated thickness, coverage ratio, and flow velocity range of the meltwater within a spanwise distribution area of ​​the blade surface based on the acquired operating parameters of the wind turbine generator set, the acquired environmental data, and the acquired pre-stored information related to the formation and evolution of meltwater on the blade surface; The inferred estimated thickness, coverage area ratio and flow velocity range are used as a parameter set related to the estimated spanwise distribution area of ​​the meltwater on the blade surface, which can reflect the aggregation state or flow characteristics of the meltwater.

5. The wind turbine blade ice pre-control method according to claim 1, characterized in that: The method further includes: Obtaining an estimated total amount of melted ice water on the blade surface, information on the stage of the current heating process, and a real-time rotation azimuth angle of the blade; Based on the obtained estimated total amount of melted ice water on the blade surface, the stage information of the current heating process, the assessed refreezing risk, and the obtained real-time rotation azimuth angle of the blade, determining whether a preset combination of pitch-assisted drainage triggering conditions is met; If it is determined that the pitch-assisted drainage triggering condition combination is met, the amplitude, rate and mode of the pitch action are determined based on the acquired real-time rotation azimuth of the blade and the preset drainage efficiency adjustment logic; The determined pitch changing action is executed.

6. The wind turbine blade ice pre-control method according to claim 5, characterized in that: The step of executing the determined pitch action includes: When executing the determined pitch changing action, monitoring the operating parameters of the driving mechanism that drives the blade to perform pitch changing, and obtaining the monitored operating parameters of the driving mechanism; comparing the monitored drive mechanism operating parameters or characteristic quantities calculated based on the monitored drive mechanism operating parameters with a preset drive mechanism operating parameter benchmark representing the blade performing the same type of pitching action in a state where de-icing water has been removed, to obtain a comparison result; If the comparison result indicates that the ice melt water separation is insufficient, a supplementary pitching action is performed or parameters of a subsequent pitching action are adjusted to facilitate the removal of the ice melt water.

7. The wind turbine blade ice pre-control method according to claim 5, characterized in that: The step of executing the determined pitch action includes: 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; Determining at least one predetermined rotation azimuth angle interval based on the estimated concentrated distribution area of ​​the meltwater in the spanwise direction of the blade and the changing characteristics of the force acting on the concentrated distribution area during blade rotation. The predetermined rotation azimuth angle interval is selected so that the determined pitch action can be performed when the estimated concentrated distribution area of ​​the meltwater is within the interval, thereby utilizing or enhancing the removal force acting on the meltwater. When the acquired real-time rotation azimuth angle of the blade enters the at least one predetermined rotation azimuth angle interval, the determined pitch change action is performed.

8. A wind turbine blade ice pre-control system, characterized in that: The system includes: An acquisition module is used to obtain operating parameters and environmental data of the wind turbine during the blade heating and deicing process; an evaluation module, configured to evaluate the risk of refreezing of the ice melt water generated on the blade surface on the blade based on the operating parameters and the environmental data, to obtain an evaluated refreezing risk; a control module, configured to control the wind turbine generator set to perform a set pitch change action when the assessed refreezing risk meets a set trigger condition, wherein the set pitch change action causes the melted ice water to be removed from the blades by changing a force acting on the melted ice water; The control module is further configured to execute a set pitch change action, wherein the set pitch change action causes the melted ice water to be removed from the blade by changing a force acting on the melted ice water, including: estimating a spanwise distribution area of ​​the ice melt water on the blade surface; Acquiring the real-time rotation azimuth angle of the blade; determining a predetermined azimuth angle interval based on the estimated spanwise distribution area of ​​the meltwater on the blade surface, such that when the blade rotates and the estimated spanwise distribution area of ​​the meltwater is within the predetermined azimuth angle interval, a resultant force acting on the meltwater causes the meltwater to be removed from the blade; When the real-time rotation azimuth angle of the blade is within the predetermined azimuth angle range, the set pitch change action is executed to change the force acting on the ice-melting water so as to remove the ice-melting water from the blade; The assessment module is further configured to assess refreezing risk. The assessment module assesses the refreezing risk of ice melt generated on the blade surface on the blade based on the operating parameters and the environmental data, and obtains the assessed refreezing risk, including: estimating the amount of ice melt water formed on the blade surface based on the operating parameters and preset physical characteristic parameters; Identify specific areas on the blade where meltwater is likely to be retained or where the surface temperature is likely to be reduced due to geometric structure or airflow, as key areas for risk assessment; analyzing a current surface temperature state of the key area based on the operating parameters, the environmental data, and the characteristics of the identified key area; Based on the operating parameters, the environmental data, and in combination with the estimated amount of meltwater and the analyzed current surface temperature state of the key area, the refreezing risk of the meltwater generated on the blade surface in the key area is evaluated to obtain the evaluated refreezing risk.

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