Wind turbine blade balancing method and system

Abstract

The application provides a wind turbine impeller balance monitoring method and system, which comprises the following steps: obtaining a position image of an impeller and a tower drum in a wind turbine, and extracting a blade period and a clearance distance of a blade in the impeller; dividing the clearance distance into clearance distances corresponding to each blade in the same period according to the blade period, and constructing a clearance distance model; determining a reference blade and an average value of the clearance distance of the reference blade according to the clearance distance model; calculating an unbalance component of the remaining blades on the impeller at a preset rotating speed according to the average value of the clearance distance of the reference blade; and comparing the unbalance component with a preset threshold value to determine an unbalance result of the remaining blades on the impeller. The wind turbine impeller balance monitoring method and system disclosed by the application have high accuracy and practicability, can effectively monitor and evaluate the balance state of the wind turbine impeller, and provide a strong guarantee for safe operation and efficient maintenance of the wind turbine.

Description

Technical Field

[0001] This invention relates to the field of wind power generation technology, specifically to a method and system for monitoring the balance of wind turbine rotors. Background Technology

[0002] With the increasing use of large-rotor wind turbines in low-wind-speed and offshore applications, the balance of wind turbine rotors has become a concern. Imbalance in the rotor can be caused by factors such as installation angle errors, pitch mechanism malfunctions, icing, and wear during operation. This rotor imbalance leads to significant vibrations and loads on the wind turbine, jeopardizing its lifespan and safety. Summary of the Invention

[0003] This invention is based on the inventor's discoveries and understanding of the following facts and problems:

[0004] During wind turbine operation, rotor balance refers to the uniform mass distribution and dynamic equilibrium of the blades and their connecting components during rotation to ensure stable operation. In practical applications, several factors can lead to rotor imbalance. First, angular errors during installation are a significant issue. Due to the complex structure of wind turbines, especially large units requiring extremely high installation precision, even minute angular deviations can be amplified at high speeds, causing imbalance. Second, the pitch mechanism, a key component for adjusting blade angles to adapt to different wind speeds, can suffer from malfunctions or performance degradation, directly resulting in uneven stress on the blades and subsequent imbalance. Furthermore, harsh environmental conditions such as icing can alter the mass and shape distribution of the blades, severely affecting rotor balance. Finally, long-term wear and tear, including bearing wear and loose bolts, also negatively impacts rotor balance.

[0005] Furthermore, rotor imbalance not only causes significant vibrations in wind turbine generators, increasing mechanical stress and shortening equipment lifespan, but can also lead to more serious structural fatigue and safety hazards. Especially in offshore applications, due to high maintenance costs and difficulties, rotor imbalance is even more challenging, posing a severe test to the long-term stable operation of wind turbine generators.

[0006] Therefore, embodiments of the present invention propose a method for monitoring the balance of a wind turbine rotor, the method comprising the following steps:

[0007] Acquire position images of the impeller and tower in the wind turbine, and extract the blade period and clearance of the blades in the impeller;

[0008] Based on the blade cycle, the clearance distance is divided into the clearance distance corresponding to each blade in the same cycle, and a clearance distance model is constructed.

[0009] Based on the aforementioned clearance distance model, determine the reference blade and the average clearance distance of the reference blade;

[0010] Based on the average clearance distance of the reference blades, calculate the unbalance component of the remaining blades on the impeller at the preset speed.

[0011] The unbalance component is compared with a preset threshold to determine the unbalance result of the remaining blades on the impeller.

[0012] In summary, the wind turbine impeller balance monitoring method provided by the embodiments of the present invention has high accuracy and practicality, and can effectively monitor and evaluate the balance state of the wind turbine impeller, providing a strong guarantee for the safe operation and efficient maintenance of wind turbines.

[0013] In some embodiments, the step of comparing the imbalance component with a preset threshold to determine the imbalance result of the remaining blades on the impeller includes:

[0014] Determine whether the unbalanced component is greater than a preset threshold;

[0015] If the unbalanced component is greater than a preset threshold, an early warning will be triggered.

[0016] In some embodiments, the step of determining the reference blade and the average clearance distance of the reference blade according to the clearance distance model includes:

[0017] Based on the aforementioned clearance distance model, the average clearance distance of each blade is calculated, and the impeller has at least three blades.

[0018] The blade with the smallest average clearance distance is determined as the reference blade.

[0019] In some embodiments, the step of acquiring position images of the impeller and tower in the wind turbine generator, and extracting the blade period and clearance distance of the blades in the impeller, includes:

[0020] Acquire position images of the impeller and tower in the wind turbine, and obtain the blade position and tower position in the position images;

[0021] Based on the relative positions of the blades and the tower, the clearance distance and blade period of each blade in the impeller are determined.

[0022] In some embodiments, the step of obtaining position images of the rotor and tower in a wind turbine includes:

[0023] The image acquisition unit acquires position images of the rotor and tower of the wind turbine in real time or at preset time intervals. The image acquisition unit is located at the bottom front end of the nacelle of the wind turbine.

[0024] In some embodiments, the steps further include:

[0025] Obtain the blade vibration acceleration and record the effective acceleration value of the blade within the time interval.

[0026] Construct a curve showing how the effective value of acceleration changes over time;

[0027] If the effective acceleration value is greater than the warning threshold for N consecutive time periods, or if the effective acceleration value shows a decreasing or increasing trend, then a warning is activated; where N≥1.

[0028] In some embodiments, the step of acquiring blade vibration acceleration and recording the effective value of blade acceleration within an interval includes:

[0029] Obtain the blade vibration acceleration and record the blade acceleration within the time interval.

[0030] Calculate the root mean square value of the blade acceleration during the interval period based on the blade acceleration during that interval period.

[0031] The root mean square value of the blade acceleration within the specified time interval is set as the effective value of the blade acceleration within the specified time interval.

[0032] In some embodiments, the steps further include:

[0033] Based on the curve of the effective acceleration value changing over time, determine the maximum value among the effective acceleration values;

[0034] The warning threshold is determined as Q times the maximum value, where Q ≥ 1;

[0035] And / or, N is set to 3.

[0036] In addition, one embodiment of the present invention provides a wind turbine rotor balance monitoring system. This system can execute the steps of the wind turbine rotor balance monitoring method described in the above embodiment. The system includes an image acquisition unit, a computing unit, and a processing unit. The processing unit, computing unit, and image acquisition unit are electrically connected. The image acquisition unit is located at the bottom front end of the wind turbine nacelle and is used to acquire position images of the rotor and tower in the wind turbine. The computing unit receives the position images sent by the image acquisition unit and extracts the blade period and clearance distance of the blades in the rotor, constructs a clearance distance model, determines a reference blade, obtains the average clearance distance of the reference blade, and calculates the unbalance component of the remaining blades on the rotor at a preset rotational speed. The processing unit receives the unbalance component sent by the computing unit and compares it with a preset threshold to determine the balance result of the blades on the rotor.

[0037] In some embodiments, the wind turbine rotor balance monitoring system further includes a vibration monitoring unit, which is electrically connected to the computing unit and the processing unit, and is located at the blade root of the wind turbine rotor blade. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the structure of a wind turbine rotor balance monitoring system provided in an embodiment of the present invention.

[0039] Figure 2 This is a flowchart illustrating a wind turbine impeller balance monitoring method according to an embodiment of the present invention.

[0040] Reference numerals: 10, image acquisition unit; 20, computing unit; 30, processing unit; 40, vibration monitoring unit; 50, storage unit. Detailed Implementation

[0041] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0042] like Figure 1 As shown in the figure, this embodiment of the invention provides a wind turbine rotor balance monitoring system. The system includes an image acquisition unit 10, a computing unit 20, and a processing unit 30. The processing unit 30, the computing unit 20, and the image acquisition unit 10 are electrically connected. The image acquisition unit 10 is located at the bottom front end of the nacelle of the wind turbine and is used to acquire position images of the rotor and tower in the wind turbine. The computing unit 20 receives the position images sent by the image acquisition unit 10, extracts the blade period and clearance distance of the blades in the rotor, constructs a clearance distance module, determines a reference blade and obtains the average clearance distance of the reference blade, and calculates the unbalance component of the remaining blades on the rotor at a preset rotational speed. The processing unit 30 receives the unbalance component sent by the computing unit 20 and compares it with a preset threshold to determine the balance result of the rotor.

[0043] Furthermore, the wind turbine rotor balance monitoring system also includes a vibration monitoring unit 40, which is electrically connected to the computing unit 20 and the processing unit 30, and is located at the blade root of the wind turbine rotor blade.

[0044] Furthermore, the wind turbine rotor balance monitoring system also includes a storage unit 50, which stores a computer program that can run on the processing unit 30, enabling the processing unit 30 and the arithmetic unit 20 to automatically monitor the balance of the wind turbine rotor.

[0045] In addition, such as Figure 2 As shown, an embodiment of the present invention also provides a method for monitoring the balance of a wind turbine rotor, which includes the following steps:

[0046] S10: Obtain the position images of the impeller and tower in the wind turbine, and extract the blade period and clearance distance of the blades in the impeller.

[0047] Specifically, the image acquisition unit acquires position images of the impeller and tower in the wind turbine in real time or at preset time intervals. Then, the processing unit processes the position images to extract the blade period of each blade in the impeller and the clearance distance between the blade and the tower. The blade period is the time required for the blade to complete one rotation.

[0048] S20, the clearance distance is divided into clearance distances corresponding to each blade in the same period according to the blade cycle, and a clearance distance model is constructed.

[0049] Specifically, the computing unit can divide the continuously collected clearance distance data into several equal-length segments based on the blade's rotation cycle. Each segment corresponds to the clearance distance data of one blade within one rotation cycle. Then, the clearance distance data of each blade is arranged in order within its rotation cycle, forming a continuously changing curve. This curve is the time-series data model of the clearance distance for that blade. Finally, the time-series data models of the clearance distance of all blades are integrated to form a complete clearance distance model. This model not only includes the clearance distance changes of each blade within one rotation cycle but also reflects the overall balance state of the wind turbine rotor.

[0050] S30, Based on the clearance distance model, determine the reference blade and the average clearance distance of the reference blade.

[0051] Specifically, based on the established clearance model, the computing unit can determine a reference blade and calculate the average clearance of that reference blade over multiple rotation cycles. The purpose of this step is to establish a stable reference standard so that subsequent assessments of the deviations of other blades relative to the reference blade can be made more accurate.

[0052] S40, calculate the unbalance component of the remaining blades on the impeller at a preset rotational speed based on the average clearance distance of the reference blades.

[0053] Specifically, the computing unit calculates the unbalance components of the remaining blades on the impeller at a preset speed by comparing the actual clearance distance of each blade with the average clearance distance of the reference blade, thereby obtaining the relative unbalance generated by each blade during rotation. These unbalance components are an important basis for evaluating the overall balance of the impeller.

[0054] Wherein, the unbalance component = the clearance distance of the blade - the clearance distance of the reference blade.

[0055] S50, compare the unbalanced component with a preset threshold to determine the unbalanced result of the remaining blades on the impeller.

[0056] Specifically, the processing unit can compare the calculated imbalance component with a preset threshold to determine the imbalance result of the remaining blades on the impeller. If the imbalance component of a certain blade exceeds the preset threshold, it indicates that the blade may be abnormal or unbalanced, requiring further inspection and maintenance. Conversely, if the imbalance components of all blades remain below the preset threshold, it indicates that the impeller is in a good balanced state and can continue to operate safely.

[0057] In summary, the wind turbine impeller balance monitoring method provided by the embodiments of the present invention has high accuracy and practicality, and can effectively monitor and evaluate the balance state of the wind turbine impeller, providing a strong guarantee for the safe operation and efficient maintenance of wind turbines.

[0058] In some embodiments, step S50 compares the imbalance component with a preset threshold to determine the imbalance result of the remaining blades on the impeller, including:

[0059] Determine whether the unbalanced component is greater than a preset threshold;

[0060] If the unbalanced component is greater than a preset threshold, an early warning will be triggered.

[0061] In other words, the processing unit carefully compares the calculated imbalance component for each blade with a preset threshold. If the imbalance component of a blade exceeds the preset threshold, it indicates a potential anomaly or imbalance, which could affect the overall performance and safety of the wind turbine. Therefore, the system immediately activates an early warning mechanism, alerting operators through various means such as sound, light, and electricity to remind them to take appropriate measures. It should be noted that the preset threshold is typically determined based on wind turbine design specifications, historical operating data, and industry standards to ensure the accuracy and reliability of the monitoring results.

[0062] In some embodiments, step S30, determining the reference blade and the average clearance distance of the reference blade according to the clearance distance model, includes:

[0063] Based on the aforementioned clearance distance model, the average clearance distance of each blade is calculated, and the impeller has at least three blades.

[0064] The blade with the smallest average clearance distance is determined as the reference blade.

[0065] Specifically, the processing unit statistically analyzes the clearance distance data for each blade over one or more rotation cycles, calculates the average clearance distance for each blade, and then compares these average clearance distances to find the minimum value. The blade corresponding to this minimum value is designated as the benchmark blade. The blade with the smallest average clearance distance is chosen as the benchmark blade because it exhibits the most stable distance from the tower or other obstacles during rotation, resulting in the most ideal balance. Therefore, using it as a reference standard for evaluating the balance of other blades ensures the accuracy and reliability of the evaluation results.

[0066] In some embodiments, step S10, acquiring position images of the impeller and tower in the wind turbine and extracting the blade period and clearance distance of the blades in the impeller, includes:

[0067] Acquire position images of the impeller and tower in the wind turbine, and obtain the blade position and tower position in the position images;

[0068] Based on the relative positions of the blades and the tower, the clearance distance and blade period of each blade in the impeller are determined.

[0069] Furthermore, the step of obtaining position images of the rotor and tower in the wind turbine includes: acquiring position images of the rotor and tower in the wind turbine in real time or at preset time intervals based on an image acquisition unit, wherein the image acquisition unit is located at the bottom of the front end of the nacelle of the wind turbine.

[0070] In this embodiment, the image acquisition unit acquires positional images of the rotor and tower of the wind turbine in real time or at preset time intervals. This image acquisition unit is carefully positioned at the bottom front end of the wind turbine nacelle to ensure that clear images of the rotor and tower can be captured, which not only avoids image distortion caused by viewing angle issues, but also ensures the stability and continuity of image acquisition.

[0071] After acquiring the location images, the system uses image processing technology to process and analyze them. This step includes identifying the positions of the blades and the tower in the images, and determining their relative positions. By accurately measuring the pixel distance between the blade edge and the tower, and combining this with known camera parameters and image scale, the system can accurately calculate the clearance distance for each blade. The clearance distance refers to the minimum distance between the blade and the tower or other obstacles during rotation.

[0072] Furthermore, the system determines the blade period based on the relative changes in blade and tower positions. The blade period refers to the time required for a blade to rotate from a specific position until it returns to that position. By measuring the positional changes of the blade in continuous images and combining this with time information, the system can accurately calculate the blade period.

[0073] In addition, the wind turbine rotor balance monitoring method also includes the steps of: obtaining the net clearance fluctuation at a preset speed based on the net clearance model, and determining the confidence level of the imbalance result, wherein the smaller the fluctuation, the higher the confidence level of the imbalance result.

[0074] In other words, based on the established clearance model, the system records and analyzes in detail the fluctuations in clearance for each blade during rotation, under preset speed conditions. These fluctuations directly reflect the stability and balance of the blade during rotation. When the blade is in ideal equilibrium, the clearance fluctuations during rotation should remain within a small range, exhibiting a relatively stable trend.

[0075] By analyzing the fluctuations in clearance distance, the system can more accurately assess the confidence level of the imbalance results. Generally speaking, the smaller the fluctuation, the better the stability of the blades during rotation, and the higher the confidence level of the imbalance results.

[0076] In some embodiments, the wind turbine rotor balance monitoring method further includes the following steps:

[0077] Obtain the blade vibration acceleration and record the effective acceleration value of the blade within the time interval.

[0078] Construct a curve showing how the effective value changes over time;

[0079] If the effective acceleration value is greater than the warning threshold for N consecutive time periods, or if the effective acceleration value shows a decreasing or increasing trend, then a warning is activated, where N≥1.

[0080] Specifically, the system acquires real-time vibration acceleration data of the blade during rotation through a vibration monitoring unit, recording and calculating the effective acceleration value of the blade at each time interval. The effective acceleration value is a parameter that comprehensively reflects the intensity and duration of blade vibration; it is obtained by squaring, averaging, and then taking the square root of the vibration acceleration signal. This step extracts the main characteristics of blade vibration, providing crucial data for subsequent analysis.

[0081] Next, the system will construct a graph showing the effective value of acceleration over time. This graph visually displays the trend of blade vibration acceleration, helping operators quickly identify potential anomalies or imbalances. By observing the fluctuations in the graph, operators can make a preliminary judgment on whether there is abnormal vibration in the blades, as well as the degree and duration of the vibration.

[0082] Furthermore, the system will immediately activate the early warning mechanism when the effective acceleration value exceeds the warning threshold for N consecutive time periods (N≥1), or when the effective acceleration value shows a significant decreasing or increasing trend. This early warning mechanism can promptly detect abnormal vibrations of the blades, understand the impeller's balance status, and remind operators to take necessary intervention measures to avoid potential safety risks and losses.

[0083] In this embodiment, N is set to 3, which means that the system will continuously monitor the effective value of the vibration acceleration of the blade in each time period, and the system will only activate the warning mechanism when the effective value of acceleration in three or more consecutive time periods exceeds the preset warning threshold.

[0084] In some embodiments, the step of acquiring blade vibration acceleration and recording the effective value of blade acceleration within an interval includes:

[0085] Obtain the blade vibration acceleration and record the blade acceleration within the time interval.

[0086] Calculate the root mean square value of the blade acceleration during the interval period based on the blade acceleration during that interval period.

[0087] The root mean square value of the blade acceleration within the specified time interval is set as the effective value of the blade acceleration within the specified time interval.

[0088] In some embodiments, the wind turbine rotor balance monitoring method further includes the following steps:

[0089] Based on the curve of the effective acceleration value changing over time, determine the maximum value among the effective acceleration values;

[0090] The warning threshold is determined as Q times the maximum value, where Q ≥ 1.

[0091] Specifically, the system first analyzes and determines the maximum value of the effective acceleration over time based on the curve of the effective acceleration value. This maximum value represents the maximum vibration intensity experienced by the blade during the monitoring period. The system then multiplies the maximum value of the effective acceleration by a coefficient Q (Q≥1), and the result is the warning threshold to ensure the sensitivity and accuracy of the warning mechanism.

[0092] The coefficient Q can be adjusted according to actual needs. Generally, the larger the Q value, the higher the warning threshold and the lower the sensitivity of the warning mechanism to the blade vibration state; conversely, the smaller the Q value, the lower the warning threshold and the higher the sensitivity of the warning mechanism to the blade vibration state. By reasonably setting the Q value, the system can ensure the accuracy of the warning while avoiding too many false alarms and missed alarms. In this embodiment, Q is set to 1.3.

[0093] In addition, one embodiment of the present invention provides a storage medium on which a computer program is stored, which, when executed by a processing unit, can implement any step in the above-described wind turbine rotor balance monitoring method.

[0094] Furthermore, the wind turbine rotor balance monitoring system provided in this embodiment of the invention can execute the wind turbine rotor balance monitoring method provided in the above embodiment. Therefore, the beneficial effects that the wind turbine rotor balance monitoring system can achieve can be referred to the beneficial effects corresponding to the wind turbine rotor balance monitoring method provided above, and will not be repeated here.

[0095] It should be noted that a storage unit may primarily include a stored program area and a stored data area. The stored program area may store the operating system, at least one application program required for a given function, etc. Furthermore, the storage unit may include high-speed random access storage units, as well as non-volatile storage units, such as hard disks, memory, plug-in hard disks, smart media cards (SMC), secure digital cards (SD), flash cards, at least one disk storage unit, flash memory devices, or other volatile solid-state storage units.

[0096] The processing unit can be a Central Processing Unit (CPU), or other general-purpose processing units, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. General-purpose processing units can be microprocessors or any conventional processing unit. The processing unit is the control center of the device, connecting all parts of the device via various interfaces and lines.

[0097] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0098] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0099] Various embodiments of the methods described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processing unit, which may be a dedicated or general-purpose programmable processing unit, capable of receiving data and instructions from a memory unit, at least one input device, and at least one output device, and transmitting data and instructions to the memory unit, the at least one input device, and the at least one output device.

[0100] The program code used to implement the method itself can be written in any combination of one or more programming languages. This program code can be provided to the processing unit or control unit of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processing unit or control unit, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The program code can be executed entirely on the machine, partially on the machine, as a standalone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0101] To provide interaction with a user, the methods described herein can be implemented on a computer having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the computer. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0102] The methods described herein can be implemented in computing systems that include backend components (e.g., as data servers), or computing systems that include middleware components (e.g., application servers), or computing systems that include frontend components (e.g., user computers with graphical user interfaces or grid browsers through which users can interact with the implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., a communication grid). Examples of communication grids include local area networks (LANs), wide area networks (WANs), the Internet, and blockchain grids.

[0103] Computer systems can include clients and servers. Clients and servers are generally geographically separated and typically interact through a communication mesh. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, a hosting product within the cloud computing service system, addressing the shortcomings of traditional physical hosts and VPS (Virtual Private Server, or simply "VPS") services, such as high management difficulty and weak business scalability. Servers can also be servers in distributed systems or servers integrated with blockchain technology.

[0104] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0105] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0106] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of the invention pertain.

[0107] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus or device (such as a computer-based system, a system including a processing unit or other system that can fetch and execute instructions from, an instruction execution system, apparatus or device).

[0108] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in a storage unit and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0109] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0110] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0111] The storage medium mentioned above can be a read-only memory unit, a disk, or an optical disk, etc. Although embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0112] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0113] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for monitoring the balance of a wind turbine impeller, characterized in that, Includes the following steps: Acquire position images of the impeller and tower in the wind turbine, and extract the blade period and clearance of the blades in the impeller; Based on the blade cycle, the clearance distance is divided into the clearance distance corresponding to each blade in the same cycle, and a clearance distance model is constructed. Based on the aforementioned clearance distance model, determine the reference blade and the average clearance distance of the reference blade; Based on the average clearance distance of the reference blades, calculate the unbalance component of the remaining blades on the impeller at the preset speed. The unbalance component is compared with a preset threshold to determine the unbalance result of the remaining blades on the impeller.

2. The method for monitoring the balance of wind turbine rotors according to claim 1, characterized in that, The step of comparing the unbalance component with a preset threshold to determine the unbalance result of the remaining blades on the impeller includes: Determine whether the unbalanced component is greater than a preset threshold; If the unbalanced component is greater than a preset threshold, an early warning will be triggered.

3. The method for monitoring the balance of wind turbine rotors according to claim 1, characterized in that, The step of determining the reference blade and the average clearance distance of the reference blade according to the aforementioned clearance distance model includes: Based on the aforementioned clearance distance model, the average clearance distance of each blade is calculated, and the impeller has at least three blades. The blade with the smallest average clearance distance is determined as the reference blade.

4. The method for monitoring the balance of wind turbine rotors according to claim 1, characterized in that, The steps to obtain position images of the impeller and tower in a wind turbine, and to extract the blade period and clearance of the impeller blades, include: Acquire position images of the impeller and tower in the wind turbine, and obtain the blade position and tower position in the position images; Based on the relative positions of the blades and the tower, the clearance distance and blade period of each blade in the impeller are determined.

5. The method for monitoring the balance of wind turbine rotors according to claim 1, characterized in that, The steps to obtain position images of the rotor and tower in a wind turbine include: The image acquisition unit acquires position images of the rotor and tower of the wind turbine in real time or at preset time intervals. The image acquisition unit is located at the bottom front end of the nacelle of the wind turbine.

6. The method for monitoring the balance of wind turbine rotors according to claim 1, characterized in that, It also includes the following steps: Obtain the blade vibration acceleration and record the effective acceleration value of the blade within the time interval. Construct a curve showing how the effective value of acceleration changes over time; If the effective acceleration value is greater than the warning threshold for N consecutive time periods, or if the effective acceleration value shows a decreasing or increasing trend, then a warning will be activated. Where N≥1.

7. The method for monitoring the balance of wind turbine rotors according to claim 6, characterized in that, The steps involve acquiring the blade vibration acceleration and recording the effective acceleration values ​​of the blade within the time intervals, including: Obtain the blade vibration acceleration and record the blade acceleration within the time interval. Calculate the root mean square value of the blade acceleration during the interval period based on the blade acceleration during that interval period. The root mean square value of the blade acceleration within the specified time interval is set as the effective value of the blade acceleration within the specified time interval.

8. The method for monitoring the balance of wind turbine rotors according to claim 6, characterized in that, It also includes the following steps: Based on the curve of the effective acceleration value changing over time, determine the maximum value among the effective acceleration values; The warning threshold is determined as Q times the maximum value, where Q ≥ 1; And / or, N is set to 3.

9. A wind turbine rotor balance monitoring system, characterized in that, The wind turbine rotor balance monitoring system can execute the steps of the wind turbine rotor balance monitoring method according to any one of claims 1 to 8. The wind turbine rotor balance monitoring system includes an image acquisition unit, a computing unit, and a processing unit. The processing unit, the computing unit, and the image acquisition unit are electrically connected. The image acquisition unit is located at the bottom front end of the nacelle of the wind turbine. The image acquisition unit is used to acquire position images of the rotor and tower in the wind turbine. The computing unit is used to receive the position images sent by the image acquisition unit and extract the blade period and clearance distance of the blades in the rotor, construct a clearance distance model, determine the reference blade and obtain the average clearance distance of the reference blade, and calculate the unbalance component of the remaining blades on the rotor at a preset speed. The processing unit is used to receive the unbalance component sent by the computing unit and compare it with a preset threshold to determine the balance result of the blades on the rotor.

10. The wind turbine rotor balance monitoring system according to claim 9, characterized in that, It also includes a vibration monitoring unit, which is electrically connected to the computing unit and the processing unit, and the vibration monitoring unit is located at the blade root of the wind turbine impeller.

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