Method for determining a friction torque calculation model of a pitch bearing and method for predicting the lifetime of a pitch system

Abstract

The present disclosure provides a determination method of a friction torque calculation model of a variable pitch bearing and a life prediction method of a variable pitch system, the determination method comprising: determining first related data of a first related quantity related to the friction torque of the variable pitch bearing in a process of executing variable pitch of a wind turbine generator set in a blade locking state; determining torque data of the friction torque of the variable pitch bearing based on the first related data and a first related relationship; and determining the friction torque calculation model of the variable pitch bearing based on the torque data and second related data of a second related quantity related to the friction torque in the process of executing variable pitch. The present disclosure solves the problem that the friction torque in the actual operation of the unit cannot be accurately determined, and a model closer to the actual operation of the unit can be determined, so that the calculated friction torque is more real and accurate.

Description

Technical Field

[0001] This disclosure relates to the field of wind power generation, and more specifically, to a method for determining a calculation model for the friction torque of a pitch bearing and a method for predicting the lifespan of a pitch system. Background Technology

[0002] In schemes involving the load of the pitch system of a wind turbine generator, accurately assessing or determining the load of the pitch system is one of the keys to the reliability of the scheme.

[0003] In determining the load on the pitch system, it is often necessary to first determine the frictional torque of the pitch bearing. This frictional torque is difficult to measure directly and is generally only possible through testing on a test bench to establish a calculation model. However, because the test environment and equipment conditions on the test bench differ significantly from the actual operating environment of the turbine unit, the accuracy of the frictional torque calculation model determined in this way may be low, making it difficult to accurately represent the actual frictional torque during turbine operation. This will affect the subsequent determination of related quantities such as the pitch system load. Furthermore, the above-mentioned testing requires the construction of a dedicated test bench, which is costly. Summary of the Invention

[0004] In view of the problem that the frictional torque in the actual operation of the unit cannot be accurately determined in the relevant technology, this disclosure proposes a method for determining the frictional torque calculation model of the pitch bearing and a method for predicting the life of the pitch system, so as to solve or at least alleviate the above problems.

[0005] The first aspect of this disclosure provides a method for determining a calculation model of the frictional torque of a pitch bearing. The method includes: during the pitch control process of a wind turbine generator in a blade-locked state, determining first correlation data of a first correlation quantity related to the frictional torque of the pitch bearing, wherein the frictional torque and the first correlation quantity satisfy a first correlation relationship; determining torque data of the frictional torque of the pitch bearing based on the first correlation data and the first correlation relationship; and determining a calculation model of the frictional torque of the pitch bearing based on the torque data and second correlation data of a second correlation quantity related to the frictional torque during the pitch control process, wherein the frictional torque calculation model characterizes the relationship between the frictional torque and the second correlation quantity.

[0006] Optionally, the first relevant quantity includes the drive wheel torque of the pitch bearing and the first bending moment of the blade root, wherein the first bending moment is the bending moment of the blade root about the blade axis; the second relevant quantity includes the second bending moment of the blade root, the blade axial load and the blade root tangential load, wherein the second bending moment is the combined bending moment of the blade root in the direction in the impeller rotation plane and the bending moment of the blade root in the direction outside the impeller rotation plane.

[0007] Optionally, the friction torque calculation model is determined by: fitting the first relevant data based on a preset friction relationship to determine a first parameter in the preset friction relationship; and determining the friction torque calculation model based on the first parameter and the preset friction relationship.

[0008] Optionally, the drive wheel torque is determined by measuring the driving torque of the pitch motor during the pitch control process; and by determining the drive wheel torque based on the gear ratio of the pitch reducer, the transmission efficiency of the pitch reducer, and the driving torque.

[0009] Optionally, the determination method further includes: obtaining the drive wheel torque of the wind turbine generator set under a preset operating condition; simulating the preset operating condition using the friction torque calculation model to obtain the simulated drive wheel torque; and adjusting the friction torque calculation model by comparing the drive wheel torque under the preset operating condition with the simulated drive wheel torque.

[0010] Optionally, the pitch control is performed under preset test conditions, wherein the test conditions include one or more of the following: the impeller is located at a preset azimuth angle; the pitch rate is a preset pitch rate; the ambient temperature is a preset ambient temperature; the operating years of the wind turbine generator set are a preset number of years; the wind speed is less than or equal to the start-up wind speed of the wind turbine generator set; whether the pitch bearing is in a worn state; whether the pitch bearing is in a fault state; and the blade mass is a preset mass.

[0011] A second aspect of this disclosure provides a method for predicting the lifespan of a pitch system in a wind turbine generator set. The method includes: acquiring operating data of the wind turbine generator set; determining the friction torque of the pitch bearing in the pitch system based on the operating data and a preset friction torque calculation model; and predicting the lifespan of the pitch system based on the friction torque, wherein the friction torque calculation model is determined based on the method for determining the friction torque calculation model of the pitch bearing according to this disclosure.

[0012] Optionally, the operating data includes blade root bending moment, blade axial load, and blade root tangential load, wherein the blade root bending moment is the combined bending moment of the blade root in the direction within the impeller's plane of rotation and the bending moment of the blade root in the direction outside the impeller's plane of rotation.

[0013] Optionally, predicting the life of the pitch system based on the frictional torque includes: determining the outer ring torque of the pitch bearing based on the frictional torque; determining the dynamic load of a first component in the pitch system using the outer ring torque as a boundary load; performing rainflow statistics on the dynamic load to determine the fatigue load information of the pitch system; and determining the fatigue damage and life of the pitch system based on the fatigue load information. The life prediction method further includes: determining the ultimate load of a second component in the pitch system using the outer ring torque as a boundary load; and determining the safety margin of the pitch system and the driving torque margin of the drive device in the pitch system based on the ultimate load.

[0014] A third aspect of this disclosure provides an electronic device comprising: a processor; and a memory for storing processor-executable instructions, wherein, when executed by the processor, the processor causes the processor to execute a method for determining a friction torque calculation model for a pitch bearing or a method for predicting the lifespan of a pitch system of a wind turbine generator according to this disclosure.

[0015] A fourth aspect of this disclosure provides a computer-readable storage medium that, when executed by a processor of an electronic device, enables the electronic device to perform a method for determining a friction torque calculation model for a pitch bearing or a method for predicting the lifespan of a pitch system of a wind turbine generator according to this disclosure.

[0016] The fifth aspect of this disclosure provides a computer program product including computer-executable instructions that, when executed by at least one processor, implement a method for determining a friction torque calculation model for a pitch bearing or a method for predicting the lifespan of a pitch system of a wind turbine generator according to this disclosure.

[0017] According to the scheme disclosed herein, during the pitch control process of a wind turbine generator under blade-locked conditions, first correlation data of a first correlation quantity related to the frictional torque of the pitch bearing can be determined. Based on the first correlation data and the first correlation relationship between the frictional torque and the first correlation quantity, the torque data of the frictional torque during the pitch control process can be determined. Combined with the data of a second correlation quantity during the pitch control process, a frictional torque calculation model characterizing the relationship between the frictional torque and the second correlation quantity can be determined. In this way, data can be collected in the whole-machine environment of the unit instead of the test bench environment, and the frictional torque calculation model can be obtained by utilizing the correlation relationship between different correlation quantities and the frictional torque. The model determined in this way is closer to the actual operating conditions of the unit, and the calculated frictional torque is more realistic and accurate. Moreover, the implementation cost of the entire scheme is lower, and there is no need to build a separate test bench. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating a method for determining a friction torque calculation model for a pitch bearing according to an exemplary embodiment of the present disclosure.

[0019] Figure 2A and Figure 2B This is a schematic diagram showing the load coordinates of a pitch system according to an exemplary embodiment of the present disclosure.

[0020] Figure 3A This is a schematic diagram showing the installation positions of sensors in a pitch system according to an exemplary embodiment of the present disclosure.

[0021] Figure 3B This is a schematic diagram illustrating load transfer of a pitch system according to an exemplary embodiment of the present disclosure.

[0022] Figure 4 This is a schematic diagram showing different azimuth angles of the rotor of a wind turbine generator set according to exemplary embodiments of the present disclosure.

[0023] Figure 5 This is a flowchart illustrating an example of a method for determining a friction torque calculation model for a pitch bearing according to an exemplary embodiment of the present disclosure.

[0024] Figure 6 This is a schematic flowchart illustrating a life prediction method for a pitch system of a wind turbine generator according to an exemplary embodiment of the present disclosure.

[0025] Figure 7 This is a schematic flowchart illustrating the prediction of the lifespan of a pitch system and the determination of the safety margin and drive margin of the pitch system according to an exemplary embodiment of the present disclosure. Detailed Implementation

[0026] The following detailed embodiments are provided to aid the reader in gaining a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will become apparent upon understanding this disclosure. For example, the order of operations described herein is merely illustrative and is not limited to those orders set forth herein, but may be changed as will become clear upon understanding this disclosure, except for operations that must occur in a specific order. Furthermore, for clarity and conciseness, descriptions of features known in the art may be omitted.

[0027] The features described herein may be implemented in different forms and should not be construed as limited to the examples described herein. Rather, the examples described herein are provided only to illustrate some of the many feasible ways of implementing the methods, apparatus, and / or systems described herein, which will become clear upon understanding the disclosure of this application.

[0028] As used herein, the term “and / or” includes any one of the associated listed items and any combination of any two or more.

[0029] Although terms such as “first,” “second,” and “third” may be used herein to describe various components, assemblies, regions, layers, or parts, these components, assemblies, regions, layers, or parts should not be limited by these terms. Rather, these terms are used only to distinguish one component, assembly, region, layer, or part from another. Thus, without departing from the teaching of the examples described herein, the first component, first assembly, first region, first layer, or first part referred to as the first component, first assembly, first region, first layer, or first part may also be referred to as the second component, second assembly, second region, second layer, or second part.

[0030] In the specification, when an element (such as a layer, region, or substrate) is described as being "on" another element, "connected to," or "bonded to" another element, the element may be directly "on" another element, directly "connected to," or "bonded to" the other element, or one or more other elements may be present in between. Conversely, when an element is described as being "directly on" another element, "directly connected to," or "directly bonded to" another element, no other elements may be present in between.

[0031] The terminology used herein is for the purpose of describing various examples only and is not intended to limit disclosure. Unless the context clearly indicates otherwise, the singular form is intended to include the plural form as well. The terms “comprising,” “including,” and “having” indicate the presence of the described features, quantities, operations, components, elements, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0032] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains upon understanding this disclosure. Unless expressly defined herein, terms (such as those defined in a general dictionary) shall be interpreted as having a meaning consistent with their meaning in the context of the relevant field and in this disclosure, and shall not be interpreted in an idealized or overly formalistic manner.

[0033] Furthermore, in the description of the examples, detailed descriptions of well-known related structures or functions will be omitted when it is believed that such detailed descriptions would lead to a vague interpretation of this disclosure.

[0034] As mentioned earlier, in related technologies, the calculation model for the friction torque of the pitch bearing can only be determined by testing on a test bench.

[0035] Specifically, during the testing process on the test bench, it is necessary to install a blade dummy model on the pitch bearing, apply a load in a certain direction to the dummy model, measure the friction torque of the pitch bearing, and then deduce the model of the friction torque. However, there are various problems in this method.

[0036] First, it cannot account for the influence of ambient temperature on the coefficient of friction, because bearing grease is very sensitive to the external environment, and different temperatures can lead to large differences in friction torque, while the test bench environment is difficult to meet the temperature control conditions. Second, it cannot account for changes in friction torque at different stages of the bearing's lifespan, such as after 1 year, 5 years, or 10 years of operation, because the test bench environment is difficult to simulate the long-term operation of bearings, and new bearings are generally used for testing. Third, the test bench can only test limited and simple working conditions by installing dummy models for measuring friction torque, which is significantly different from the complex load environment of the whole machine. The universality of the test results is unclear, and it is difficult to achieve a closed loop of test-simulation. Fourth, test bench testing requires the construction of a dedicated test bench, which is costly.

[0037] Besides the aforementioned test bench methods, in some cases, empirical methods are also used to determine the calculation model for friction torque, such as using empirical values ​​for the friction coefficient of the calculation model. However, such methods have poor accuracy and versatility, and lack scientifically reliable basis.

[0038] In view of the above problems, this disclosure provides a method for determining the friction torque calculation model of a pitch bearing, a method for predicting the life of a pitch system of a wind turbine generator, an electronic device, a computer-readable storage medium, and a computer program product, which can solve or at least alleviate the above problems.

[0039] According to a first aspect of an exemplary embodiment of the present disclosure, a method for determining a calculation model for the frictional torque of a pitch bearing is provided. This method can be performed by an electronic device with computational capabilities. The electronic device may be, for example, a terminal device or a server, wherein the terminal device may be such as a tablet computer, a laptop computer, a digital assistant, etc.; the server may be a standalone server, a server cluster, a cloud computing platform, or a virtualization center.

[0040] Here, electronic devices can be installed at the wind turbine generator or wind farm, and can be communicatively connected to the measuring device or data center of the wind turbine generator or wind farm, thereby obtaining the data required to perform the above methods, such as the generator's operating data.

[0041] According to embodiments of this disclosure, the method for determining the friction torque calculation model of the pitch bearing may include the following steps: like Figure 1As shown, in step S110, during the pitch control process of the wind turbine generator set in the blade-locked state, the first related data of the first related quantity related to the friction torque of the pitch bearing can be determined.

[0042] Here, the frictional torque can satisfy a first correlation relationship with the first relevant quantity. For example, the change of the first relevant quantity can be correlated with the change of the frictional torque, and the first relevant quantity can be a variable that can be obtained through measurement or simulation. In addition, the wind turbine generator set can be, for example, a horizontal axis wind turbine generator set, which can include subsystems such as blades, nacelle (including generator and transmission system), and tower.

[0043] As an example, the first relevant quantity may include the drive wheel torque of the pitch bearing and the first bending moment at the blade root, where the first bending moment can be the bending moment at the blade root about the blade axis. Here, the blade axis direction can refer to the direction from the center of the blade root to the blade tip, or it can be considered as the length direction of the blade, such as... Figure 2A As shown, the first bending moment can be the bending moment Mz at the blade root in the Z direction around the blade axis. This first bending moment reflects the component of the bending moment acting at the blade root along the blade's length. This bending moment may be caused by various factors such as wind force, the blade's own weight, and centrifugal force. Furthermore, the first relevant data may include data corresponding to only one blade, or it may include data corresponding to multiple blades. For example, the first relevant data may include the drive wheel torque data and the first bending moment data for each blade in a three-bladed turbine unit.

[0044] During blade pitch control, the three loads—bending moment at the blade root, frictional torque (e.g., the frictional torque of the pitch bearing that can withstand it), and drive wheel torque—can be in a state of dynamic equilibrium along the pitch direction (rotation direction around the blade axis). Therefore, if two of these quantities are measured, the third quantity can be calculated. Thus, the first correlation can be established as shown in equation (1): Mf=Mz-Md'(1) Where Mf represents the frictional torque of the pitch bearing, Mz represents the first bending moment mentioned above, and Md' represents the torque of the drive wheel.

[0045] Returning to step S110, the pitch system of the wind turbine can be controlled to perform pitch control while the blades are locked, and the first relevant quantity during the pitch control process can be determined.

[0046] For example, in the example above, the drive wheel torque can be determined by measuring the drive torque of the pitch motor during pitch control; and by determining the drive wheel torque based on the gear ratio of the pitch reducer, the transmission efficiency of the pitch reducer, and the drive torque.

[0047] Specifically, such as Figure 3A and Figure 3BAs shown, a sensor can be installed at the measuring point between the pitch motor and the pitch reducer. This sensor can be used to sense the driving torque Md output by the pitch motor. Based on the gear ratio and transmission efficiency of the pitch reducer, this driving torque Md can be converted to the drive wheel end to obtain the drive wheel torque Md'. In this way, even if the drive wheel torque at the outer ring of the pitch bearing cannot be measured, the drive wheel torque can be calculated using the sensing data from the pitch motor side.

[0048] Furthermore, in the above example, the first bending moment during the pitch control process can be determined through simulation. For example, the operating and control parameters of the unit during the pitch control process can be input into a preset unit simulation model (e.g., a unit dynamics model) to obtain the first bending moment. Alternatively, the first bending moment can also be determined by measurement. For example, a sensor can be installed at the blade root to measure the first bending moment or to measure relevant quantities used to calculate the first bending moment, thereby determining the first bending moment.

[0049] It should be noted that although the above example of the first correlation quantity and the first correlation relationship is illustrated using Equation (1), the embodiments of this disclosure are not limited to the above example. For example, the correlation between other first correlation quantities and friction torque can also be established based on empirical methods.

[0050] In step S120, the torque data of the frictional torque of the pitch bearing can be determined based on the first correlation data and the first correlation relationship.

[0051] In this step, given the first correlation data of the first correlation quantity, the first correlation data can be substituted into the first correlation relationship (e.g., the above formula (1)) to calculate the torque data of the friction torque during the current pitch change process. For example, the first correlation data can be the time series data during the pitch change process, and correspondingly, the torque data can also be the time series data, thereby obtaining the torque curve of the friction torque.

[0052] Furthermore, as an example, the pitching process described above can be performed under preset test conditions, thereby obtaining torque data and torque curves of friction torque under different test conditions.

[0053] For example, test conditions may include one or a combination of the following: the impeller is located at a preset azimuth angle; the pitch rate is a preset pitch rate; the ambient temperature is a preset ambient temperature; the operating years of the wind turbine are a preset number of years; the wind speed is less than the wind speed required for the wind turbine to start up; whether the pitch bearing is worn; whether the pitch bearing is faulty; and the blade mass is a preset mass.

[0054] Specifically, the preset azimuth angle can include multiple azimuth angles, such as... Figure 4 As shown, multiple azimuth angles can include 0 degrees, 30 degrees, 60 degrees and 90 degrees.

[0055] In one example, the impeller can be locked to different azimuth angles to perform pitch control separately, obtaining the corresponding first correlation data and calculating the torque data. Alternatively or additionally, in another example, the first correlation data of multiple blades can be determined during the same pitch control process. Since these blades are at different angles and their weight and shape are basically the same, the first correlation data of different blades determined in the same instance can be combined into a single set of first correlation data for a single blade at different impeller azimuth angles, thus reducing the number of tests.

[0056] The preset pitch rate can include multiple pitch rates. Test conditions can include, for example, pitching at multiple different pitch rates. In this way, relevant data can be obtained and corresponding torque data can be calculated. The preset pitch rate can be set according to actual needs.

[0057] The preset ambient temperature can include multiple ambient temperatures, such as winter and summer. Test conditions can include, for example, pitch control under multiple different ambient temperatures; and / or, the wind turbine generator set includes multiple units from different temperature regions. In this way, first relevant data can be obtained under different ambient temperatures, and corresponding torque data can be calculated. The preset ambient temperature here can be set according to actual needs.

[0058] The preset service life can include multiple periods, such as new units, 3 years, 5 years, 10 years, 15 years, 20 years, etc. Test conditions can include, for example, using wind turbine generators with multiple different service lives to perform pitch control. In this way, the first relevant data for units with different service lives can be obtained and the corresponding torque data can be calculated. The preset service life can be set according to actual needs.

[0059] The preset mass can include multiple blade masses. For example, different blade models can be used to perform pitch tests, thus taking into account the test results under different blade root loads.

[0060] Furthermore, the test conditions may include at least one of the following: the pitch bearing is in a worn state; the pitch bearing is not in a worn state; the pitch bearing is in a worn state; the pitch bearing is not in a faulty state. In this way, first relevant data under different bearing conditions can be obtained, and corresponding torque data can be calculated. When the test conditions include pitch bearing failure or different wear conditions, in this method, the failure status or current wear degree of the pitch bearing can also be determined based on the friction torque calculation model (e.g., coefficients of the friction torque calculation model) corresponding to the faulty or worn pitch bearing. For example, the friction torque of the pitch bearing of the current unit can be determined by measuring the first bending moment and drive wheel torque of the current unit, thereby deriving the current friction torque calculation model (e.g., model coefficients). The current friction torque calculation model (e.g., model coefficients) can be compared (or matched) with a pre-determined friction torque calculation model (e.g., model coefficients) corresponding to the faulty or worn pitch bearing to identify whether the pitch bearing of the current unit is faulty or to determine the wear degree of the pitch bearing of the current unit. For example, if the difference between the currently determined model coefficients and the model coefficients under a certain preset fault or wear condition is less than a preset difference, it can be determined that the current pitch bearing is under that preset fault or wear condition.

[0061] Furthermore, during the aforementioned pitch test, the wind speed can be less than or equal to the wind turbine's start-up wind speed (or cut-in wind speed), which can be, for example, but is not limited to, 3 m / s. Performing the pitch test when the on-site wind speed is less than or equal to the start-up wind speed has two advantages: firstly, due to the low wind speed, the air load is very small, and the blade root load is mainly affected by the blade's own weight (which is easily determined), and the blade root load caused by gravity can be easily calculated from the blade design parameters; secondly, below the start-up wind speed, the turbine is essentially in a shutdown state, and the test can avoid causing additional losses in wind farm power generation. Therefore, choosing to perform the pitch test for determining the friction torque calculation model under such wind speed conditions allows for the acquisition of test data for the model with minimal or no loss of power generation. However, the test conditions of this disclosure are not limited to the aforementioned wind speeds. Depending on the aerodynamic characteristics of the turbine, other wind speeds can also be used. For example, the method of the embodiments of this disclosure can also be applied when the wind speed is greater than the start-up wind speed.

[0062] In the methods of the embodiments of this disclosure, the above-mentioned test conditions can be set individually or in combination. For example, the test conditions can be: performing pitch control at each preset pitch rate and at each preset ambient temperature.

[0063] By setting various test conditions and combinations thereof, the friction torque of the unit can be tested under conditions such as different ambient temperatures and different years of operation. The influence of different conditions on the modeling of the friction torque calculation model can be considered, making the determined model more targeted. For example, the corresponding friction torque can be calculated for various test conditions and combinations thereof, so that a model matching the unit conditions of the target unit in the current simulation or design process can be used, making the simulation or design results closer to the real situation.

[0064] In step S130, the friction torque calculation model of the pitch bearing can be determined based on the torque data and the second correlation data of the second correlation quantity related to the friction torque during the pitch process.

[0065] Here, the friction torque calculation model can characterize the relationship between friction torque and a second related quantity. For example, the second related quantity can be the blade root load.

[0066] Specifically, the relationship between the torque data determined by the first correlation quantity and the first correlation relationship and the second correlation quantity can be analyzed to obtain the friction torque calculation model. In this way, data can be collected during unit operation without the need to build a test bench, and the determined calculation model is more realistic and accurate.

[0067] In step 130, determining the friction torque calculation model for the pitch bearing can, for example, refer to determining the parameters in the preset friction relationship.

[0068] As an example, the friction torque calculation model can be determined as follows: based on a preset friction relationship, fit the first relevant data to determine the first parameter in the preset friction relationship; based on the first parameter and the preset friction relationship, determine the friction torque calculation model.

[0069] Here, the preset friction relationship can be determined by empirical methods or simulation derivation. The preset friction relationship can represent the relationship between the second related quantity and the friction torque. This friction relationship can include a first parameter to be determined, which can be one or more.

[0070] For example, the pre-defined friction relationship can be expressed by the following equation (2): (2) In equation (2) above, the second relevant quantities include the second bending moment Mxy at the blade root, the axial load Fz of the blade, and the tangential load Fxy at the blade root. Mo is the base value, which can be preset. This value can be the initial frictional torque caused by the bearing's own preload (rather than the frictional torque caused by the load of the blade's bending moment). For example, it can be determined when the bearing leaves the factory, for example, obtained on the test bench of the bearing manufacturer. a, b, and c represent the parameters in the preset frictional relationship, respectively. With these parameters determined, the form of the preset frictional relationship is determined, which can be used as the frictional torque calculation model.

[0071] In this example, such as Figure 2A As shown, the second bending moment Mxy can be the combined bending moment of the blade root in the direction in the impeller's rotation plane Mx and the bending moment of the blade root in the direction out of the impeller's rotation plane My; the blade root tangential load Fxy can be the combined load in the direction of the combination of the blade root load Fx in the direction out of the plane and the blade root load Fy in the direction in the plane; the blade axial load is Fz.

[0072] Here, as Figure 2B As shown, the blade root tangential load Fxy, the blade axial load Fz, and the second bending moment Mxy can be expressed, for example, by the following equations (3) to (5): (3) (4) (5) Where G represents the weight of the blade. The angle between the current blade axis direction (or blade length direction) and the vertical direction is represented by L, which represents the distance between the blade's center of gravity and the hub center. Although the determination of the blade root tangential load Fxy, the blade axial load Fz, and the second bending moment Mxy according to the above equations (3) to (5) is described here, this disclosure is not limited to this, and the above blade root loads can also be obtained using specialized testing equipment.

[0073] It should be noted that the above-mentioned preset friction relationship can be an empirical formula obtained by empirical method. The expression of the preset friction relationship in the embodiments of this disclosure is not limited to this. For example, it can be adjusted based on the above formula (2), or other empirical formulas can be used as the preset friction relationship.

[0074] In embodiments of this disclosure, the first relevant quantity can be an unknown quantity, or a quantity to be designed, during the unit design or simulation process. This first relevant quantity can be measured during actual unit operation or calculated based on measured values. The second relevant quantity can be a known quantity, or a design-given quantity, during the unit design or simulation process. Therefore, during the design or simulation process, given the second relevant quantity, the design friction torque can be determined based on the friction torque calculation model determined according to the method of embodiments of this disclosure. Thus, the first relevant quantity, as the quantity to be designed, can be determined based on the first relevant relationship and the design friction torque.

[0075] For example, in the design or simulation process, the drive wheel torque can be the quantity to be designed, while the first bending moment, second bending moment, blade axial load, and blade root tangential load can be given quantities. Therefore, the friction torque calculation model determined by this method (e.g.) can be used. The design friction torque is determined by considering the second bending moment, blade axial load, and blade root tangential load. The drive wheel torque can be determined based on the design friction torque and the first correlation (e.g., Mf=Mz-Md') to achieve the design or simulation of the unit.

[0076] Furthermore, during the aforementioned pitch control process, the second related data corresponding to the torque data can be determined. Here, "corresponding to the torque data" can mean, for example, that the second related data corresponds to the torque data in terms of time sequence. For instance, for the pitch control test process of a certain unit, on the one hand, the torque data at time t can be determined based on the first related relationship and the first related data at time t; on the other hand, the second related data during the pitch control process can be determined, such as the second related data at time t, thereby establishing a correspondence between the torque data at time t and the second related data. When the correspondence between torque data and the second related data at multiple times is determined, a friction torque calculation model can be fitted based on the aforementioned expression of the preset friction relationship.

[0077] Furthermore, as an example, as mentioned above, one or more test conditions can be set to determine the friction torque calculation model under different test conditions. This allows for differentiation of the pitch conditions under which the pitch bearing operates, eliminating uncertainties between different conditions and preventing errors between the calculated friction torque and its associated system loads and measured values. For example, underestimating the pitch system load under constant pitch conditions or overestimating the pitch system load under pitch conditions could affect the accuracy of pitch system load and life predictions.

[0078] Specifically, first relevant data, torque data, and second relevant data can be determined under multiple test conditions to establish a friction torque calculation model for each test condition. An example of determining a friction torque calculation model under multiple test conditions is given below.

[0079] As an example, the test can be conducted when the on-site wind speed is below 3 m / s. In step S1, the impeller can be locked to a specific azimuth angle, such as 0 degrees, 30 degrees, 60 degrees or 90 degrees.

[0080] In step S2, during the pitch control process, the impeller can be controlled to operate at a uniform pitch rate among multiple preset pitch rates. The pitch angle is recorded in real time to obtain the pitch angle curve. Based on the impeller azimuth angle and pitch angle information, and according to the designed blade center of gravity position, the gravity-induced blade root loads Mz, Mxy, and Fxy are calculated at different pitch angles. Here, since the wind speed is very low, the aerodynamic blade root load can be ignored. In this step, multiple pitch angles can be used for pitch control to obtain more detailed test results.

[0081] In step S3, the driving torque Md of the pitch motor can be measured synchronously during the pitch control process (e.g., during the execution of step S2 above) to obtain data or curves of the driving torque Md.

[0082] In step S4, the driving torque Md can be converted to the drive wheel end to obtain the drive wheel torque Md' according to the transmission ratio and transmission efficiency of the pitch reducer.

[0083] In step S5, the frictional torque data or curve Mf of the pitch bearing at the current pitch rate can be calculated based on a first correlation such as Equation (1).

[0084] As an example, in step S6, different test conditions can be set for the pitch rate. For example, different pitch rates can be set to repeat steps S2 to S5 above to obtain friction torque data or curve Mf at different pitch rates.

[0085] As an example, in step S7, different test conditions can be set for the impeller azimuth angle. For example, different impeller azimuth angles can be set to repeat the above steps S1 to S6 to obtain friction torque data or curves Mf under different azimuth angles and different pitch rates.

[0086] As an example, in step S8, different test conditions can be set for the ambient temperature. For example, steps S1 to S7 can be repeated under different ambient temperatures (such as summer and winter or units in different temperature regions) to obtain friction torque data or curves Mf under different ambient temperatures, different azimuth angles and different pitch rates.

[0087] As an example, in step S9, different test conditions can be set for the operating years of the unit. For example, the above steps S1 to S8 can be repeated under different operating years (such as new unit, 3 years, 5 years, 10 years, 15 years, 20 years, etc.) to obtain friction torque data or curves Mf under different operating conditions, different ambient temperatures, different azimuth angles and different pitch rates.

[0088] Based on the friction torque data or curve Mf obtained above and the corresponding blade root load curves Mz, Mxy, and Fxy, the first parameters under the corresponding test conditions, such as a, b, and c, can be obtained by fitting the preset friction relationship, such as equation (2), through mathematical methods. Here, the values ​​of the first parameters under different test conditions can be stored in a structured form, such as a matrix or a table, for example, in a database. Thus, when calculating the friction torque later, the database can be queried to find the test conditions that match the current conditions for calculating the friction torque, and the first parameters and / or friction torque calculation model under the test conditions can be used to calculate the friction torque.

[0089] Furthermore, the first parameter in the friction torque calculation model and / or preset friction relationship determined by the method of the embodiments of this disclosure can be applied to the dynamic model of the entire wind turbine generator to perform simulation calculations for real working conditions and compare them with the test results under such working conditions, thereby fine-tuning and correcting the first parameter in the friction torque calculation model and / or preset friction relationship.

[0090] Specifically, the method may further include: obtaining the drive wheel torque of the wind turbine generator under preset operating conditions; simulating the preset operating conditions using a friction torque calculation model to obtain the simulated drive wheel torque; and adjusting the friction torque calculation model by comparing the drive wheel torque under the preset operating conditions with the simulated drive wheel torque.

[0091] For example, the simulated drive wheel torque can be obtained in the following ways: the second relevant quantity under the preset working condition can be determined, and the data of the second relevant quantity can be substituted into the friction torque calculation model to obtain the friction torque under the preset working condition; the first bending moment under the preset working condition can be determined through the simulation model of the wind turbine generator set; based on the friction torque and the first relevant relationship under the preset working condition, the simulated drive wheel torque can be determined.

[0092] Here, the preset working condition can be any working condition, which can be selected according to actual needs. In addition, the preset working condition can include multiple working conditions, and the model can be adjusted under each of the multiple working conditions.

[0093] In the above process, on the one hand, such as Figure 3AAs shown, a sensor can be installed at the measuring point between the pitch motor and the pitch reducer. This sensor can be used to sense the driving torque output by the pitch motor, and based on the transmission ratio and efficiency of the pitch reducer, the corresponding drive wheel torque can be determined. This drive wheel torque can be considered as the actual value. On the other hand, the preset working condition can be simulated to obtain the corresponding drive wheel torque. Based on the difference between the drive wheel torque calculated from the measured data and the simulated drive wheel torque, the friction torque calculation model can be adjusted. For example, the first parameter mentioned above can be adjusted to make the simulated value as close as possible to the actual value.

[0094] Furthermore, under each preset operating condition, multiple simulations and tests can be performed for comparison, ultimately fitting the optimal friction torque calculation model and / or the value or curve of the first parameter of the unit.

[0095] The friction torque calculation model can be adjusted in the above way to make it closer to the real situation.

[0096] Figure 5 A flowchart illustrating an example of a method for determining a friction torque calculation model for a pitch bearing according to an embodiment of the present disclosure is shown.

[0097] like Figure 5 As shown, in step S510, the impeller can be locked to a certain impeller azimuth angle at wind speeds below 3 m / s. In step S520, the pitch can be adjusted at a preset pitch rate, and the output torque Md' at the drive end can be measured. In step S530, the blade root load, such as Mz, Fxy, and Mxy described above, can be calculated based on the blade centroid and blade azimuth information. In step S540, the bearing friction torque Mf = Mz - Md' can be calculated. In step S550, the first parameters a, b, and c can be fitted to a preset friction relationship. In step S560, a first correction process can be performed, specifically, the first parameters can be measured at different temperatures and operating lengths to form a corrected first parameter library. In step S570, a second correction process can be performed, specifically, the first parameters can be substituted into the simulation model to conduct simulation comparisons under complex operating conditions and correct the first parameters. In step S580, the final first parameter library can be determined, for example, it can be applied to the development of pitch systems and the prediction of pitch system lifespan.

[0098] According to a second aspect of an exemplary embodiment of the present disclosure, a method for predicting the lifetime of a pitch system of a wind turbine generator is provided, the method comprising the following steps: like Figure 6 As shown, in step S610, the operating data of the wind turbine generator set can be obtained.

[0099] In step S620, the friction torque of the pitch bearing in the pitch system can be determined based on the operating data and the preset friction torque calculation model.

[0100] Here, the friction torque calculation model can be determined based on the method for determining the friction torque calculation model of the pitch bearing according to the embodiments of this disclosure.

[0101] The operating data can be determined based on the variables in the friction torque calculation model. For example, taking the friction torque calculation model with the relationship shown in equation (2) above as an example, the operating data can include blade root bending moment, blade axial load, and blade root tangential load. Among them, the blade root bending moment can be the combined bending moment of the blade root in the direction in the impeller's rotation plane and the bending moment of the blade root in the direction outside the impeller's rotation plane. For example, as Figure 7 As shown, in step S710, the leaf root loads Mx, My, Mz, Fx, Fy, and Fz can be calculated or measured.

[0102] In this step, relevant data from the operational data can be substituted into the friction torque calculation model to calculate the friction torque. For example, as... Figure 7 As shown, in step S720, the bearing friction torque Mf can be calculated by combining the friction torque calculation model (e.g., the first parameter used to substitute the preset correlation relationship) and the blade root load.

[0103] In step S630, the lifespan of the pitch system can be predicted based on the frictional torque.

[0104] Given a fixed frictional torque, the lifespan of a pitch system can be predicted. For example, such as... Figure 7 As shown, step S630 may include: In step S730, the outer ring torque of the pitch bearing can be determined based on the frictional torque.

[0105] For example, the outer ring torque of a pitch bearing can be calculated based on the bearing load balance principle, such as Md'=Mz-Mf.

[0106] In step S740, the dynamic load of the first component in the pitch system can be determined by using the outer ring torque as the boundary load.

[0107] For example, the outer ring torque Md' can be used as the boundary load input to calculate the dynamic loads on each component in the pitch system. The components mentioned here can be preset components related to the lifespan of the pitch system.

[0108] In step S750, rainflow statistics can be performed on the dynamic load to determine the fatigue load information of the pitch system.

[0109] For example, rainflow statistics can be performed on the dynamic loads of various components of the pitch system to obtain fatigue load information of the components.

[0110] In step S760, fatigue damage and lifespan of the pitch system can be determined based on fatigue load information.

[0111] Specifically, fatigue damage and lifespan of each component in the pitch system can be calculated based on fatigue load information of each component.

[0112] Furthermore, in the lifetime prediction method of the embodiments of this disclosure, the safety margin of the pitch system and the drive margin of the drive device can also be determined.

[0113] As an example, such as Figure 7 As shown, the life prediction method may further include: step S770, determining the ultimate load of the second component in the pitch system by using the outer ring torque as the boundary load; step S780, determining the safety margin of the pitch system and the driving torque margin of the drive device in the pitch system based on the ultimate load.

[0114] Specifically, the outer ring torque Md' can be used as the boundary load input to calculate the ultimate load of each component of the pitch system. Based on the ultimate load of each component, the safety margin of each component and the drive margin of the drive unit can be calculated.

[0115] As described above, according to the method for determining the friction torque calculation model of this disclosure, the pitch friction model measurement can be performed in the whole machine environment instead of the test bench environment, making the model more realistic and reducing costs.

[0116] Furthermore, based on the method for determining the friction torque calculation model disclosed herein, the friction model of the pitch bearing at different temperatures can be obtained by measuring units in different regions or seasons. Additionally, relevant patterns can be obtained by measuring the friction torque calculation model at different operating stages throughout the entire life cycle of the pitch bearing, providing a reference for the unit design stage (considering the friction torque calculation model at different stages throughout the entire life cycle for design evaluation results in greater precision).

[0117] Furthermore, based on the method for determining the friction torque calculation model disclosed herein, a large amount of test data under complex operating conditions of the unit (such as temperature, operating years, speed, wind speed, load, etc.) is used to fit the pitch friction torque calculation model. This data is then input into the simulation model for simulation and testing comparison under actual operating conditions. The friction torque calculation model is continuously corrected (e.g., by adjusting model parameters) until it reaches its optimum, achieving a closed-loop design of test-simulation. Moreover, the method for determining the friction torque calculation model disclosed herein can handle the closed-loop verification of whole-unit operating data under complex environments through simulation-testing, further correcting the friction torque calculation model (e.g., by adjusting model parameters), achieving accurate modeling, and supporting unit design.

[0118] Furthermore, based on the method for determining the friction torque calculation model disclosed herein, the simulation-test closed loop of the whole machine load can be realized by measuring the friction torque calculation model in the whole machine environment. The measured model parameters (such as the first parameter mentioned above) can be seamlessly connected and applied to the simulation evaluation in the pitch system design stage for accurate evaluation and life prediction of the internal load of the pitch system.

[0119] According to a third aspect of an exemplary embodiment of the present disclosure, an electronic device is provided, the electronic device comprising: a processor; and a memory for storing processor-executable instructions, wherein, when executed by the processor, the processor-executable instructions cause the processor to execute a method for determining a friction torque calculation model for a pitch bearing or a method for predicting the life of a pitch system according to an exemplary embodiment of the present disclosure.

[0120] As an example, an electronic device can be a PC, tablet, personal digital assistant, smartphone, or other device capable of executing the aforementioned set of instructions. Here, the electronic device is not necessarily a single device; it can be any collection of devices or circuits capable of executing the aforementioned instructions (or instruction sets) individually or in combination. The electronic device can also be part of an integrated control system or system manager, or can be configured to interconnect locally or remotely (e.g., via wireless transmission) through an interface.

[0121] In electronic devices, a processor may include a central processing unit (CPU), a graphics processing unit (GPU), a programmable logic device, a dedicated processor system, a microcontroller, or a microprocessor. By way of example and not limitation, a processor may also include analog processors, digital processors, microprocessors, multi-core processors, processor arrays, network processors, etc.

[0122] The processor can execute instructions or code stored in memory, which can also store data. Instructions and data can also be sent and received over a network via a network interface device, which can employ any known transport protocol.

[0123] Memory can be integrated with the processor; for example, RAM or flash memory can be housed within an integrated circuit microprocessor. Alternatively, memory can comprise a separate device, such as an external disk drive, storage array, or other storage device that can be used by any database system. Memory and processor can be operatively coupled, or can communicate with each other, for example, via I / O ports, network connections, etc., enabling the processor to read files stored in the memory.

[0124] In addition, electronic devices may include video displays (such as liquid crystal displays) and user interaction interfaces (such as keyboards, mice, touch input devices, etc.). All components of the electronic device may be interconnected via buses and / or networks.

[0125] According to a fourth aspect of an exemplary embodiment of the present disclosure, a computer-readable storage medium is provided, wherein when instructions in the computer-readable storage medium are executed by a processor of an electronic device, the electronic device is enabled to perform a method for determining a friction torque calculation model for a pitch bearing or a method for predicting the life of a pitch system according to an exemplary embodiment of the present disclosure.

[0126] Specifically, the method for determining the friction torque calculation model of the pitch bearing or the method for predicting the life of the pitch system according to embodiments of this disclosure can be programmed into a computer program and stored on a computer-readable storage medium. When the instructions in the computer-readable storage medium are executed by at least one processor, the at least one processor is caused to perform the method for determining the friction torque calculation model of the pitch bearing or the method for predicting the life of the pitch system according to exemplary embodiments of this disclosure. Examples of computer-readable storage media include: read-only memory (ROM), random access programmable read-only memory (PROM), electrically erasable programmable read-only memory (EEPROM), random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), flash memory, non-volatile memory, CD-ROM, CD-R, CD+R, CD-RW, CD+RW, DVD-ROM, DVD-R, DVD+R, DVD-RW, DVD+RW, DVD-RAM, BD-ROM, BD-R, BD-R LTH, BD-RE, Blu-ray or optical disc storage, hard disk drive (HDD), solid-state drive (SSD), card storage (such as multimedia cards, secure digital (SD) cards, or ultra-fast digital (XD) cards), magnetic tape, floppy disk, magneto-optical data storage device, optical data storage device, hard disk, solid-state drive, and any other device configured to store computer programs and any associated data, data files, and data structures in a non-transitory manner and to provide the computer programs and any associated data, data files, and data structures to a processor or computer so that the processor or computer can execute the computer programs. In one example, the computer programs and any associated data, data files, and data structures are distributed across a networked computer system, such that the computer programs and any associated data, data files, and data structures are stored, accessed, and executed in a distributed manner through one or more processors or computers.

[0127] According to a fifth aspect of an exemplary embodiment of the present disclosure, a computer program product is provided, including computer-executable instructions, which, when executed by at least one processor, implement a method for determining a friction torque calculation model for a pitch bearing or a method for predicting the life of a pitch system according to an exemplary embodiment of the present disclosure.

[0128] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the claims.

[0129] Furthermore, it should be noted that although several examples of each step have been described above with reference to the specific accompanying drawings, it should be understood that the embodiments of this disclosure are not limited to the combinations given in the examples. The steps appearing in different drawings can be combined, and the execution order of each step can be changed, which will not be exhaustive here.

[0130] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

[0131] The specific embodiments of this disclosure have been described in detail above. Although some embodiments have been shown and described, those skilled in the art should understand that modifications and variations can be made to these embodiments without departing from the principles and spirit of this disclosure, which are defined by the claims and their equivalents. Such modifications and variations should also be within the protection scope of the claims of this disclosure.

Claims

1. A method for determining the calculation model of friction torque for a pitch bearing, characterized in that, The determination method includes: During the pitch control process of a wind turbine generator set in blade-locked state, first correlation data of a first correlation quantity related to the friction torque of the pitch bearing is determined, wherein the friction torque and the first correlation quantity satisfy a first correlation relationship; Based on the first relevant data and the first relevant relationship, the torque data of the frictional torque of the pitch bearing is determined; Based on the torque data and the second related data of the second related quantity associated with the friction torque during the pitching process, a friction torque calculation model for the pitch bearing is determined, wherein the friction torque calculation model characterizes the relationship between the friction torque and the second related quantity.

2. The determination method according to claim 1, characterized in that, The first relevant quantity includes the drive wheel torque of the pitch bearing and the first bending moment at the blade root, wherein the first bending moment is the bending moment at the blade root about the blade axis. The second relevant quantity includes the second bending moment of the blade root, the axial load of the blade, and the tangential load of the blade root, wherein the second bending moment is the combined bending moment of the blade root in the direction within the impeller's rotation plane and the bending moment of the blade root in the direction outside the impeller's rotation plane.

3. The determining method according to claim 1 or 2, characterized in that, The friction torque calculation model is determined in the following manner: Based on a preset friction relationship, the first relevant data is fitted to determine the first parameter in the preset friction relationship; Based on the first parameter and the preset friction relationship, the friction torque calculation model is determined.

4. The determination method according to claim 2, characterized in that, The drive wheel torque is determined in the following manner: The driving torque of the pitch motor is measured during the pitch control process. The torque of the drive wheel is determined based on the transmission ratio of the pitch reducer, the transmission efficiency of the pitch reducer, and the driving torque.

5. The determination method according to claim 4, characterized in that, The determination method further includes: Obtain the drive wheel torque of the wind turbine generator set under preset operating conditions; Using the aforementioned friction torque calculation model, the preset working condition is simulated to obtain the simulated drive wheel torque; The friction torque calculation model is adjusted by comparing the drive wheel torque under the preset working conditions with the simulated drive wheel torque.

6. The determination method according to claim 1, characterized in that, The pitch control is performed under preset test conditions, which include one or more of the following: the impeller is located at a preset azimuth angle; the pitch rate is a preset pitch rate; the ambient temperature is a preset ambient temperature; the operating years of the wind turbine generator are a preset number of years; the wind speed is less than or equal to the start-up wind speed of the wind turbine generator; whether the pitch bearing is in a worn state; whether the pitch bearing is in a fault state; and the blade mass is a preset mass.

7. A method for predicting the lifespan of a pitch system in a wind turbine generator set, characterized in that, The lifetime prediction method includes: Obtain operating data of wind turbine generators; Based on the operating data and the preset friction torque calculation model, the friction torque of the pitch bearing in the pitch system is determined. Based on the aforementioned frictional torque, the lifespan of the pitch system can be predicted. The friction torque calculation model is determined based on the method for determining the friction torque calculation model of the pitch bearing according to any one of claims 1 to 6.

8. The lifetime prediction method according to claim 7, characterized in that, The operating data includes blade root bending moment, blade axial load, and blade root tangential load. The blade root bending moment is the combined bending moment of the blade root in the direction within the impeller's rotation plane and the bending moment of the blade root in the direction outside the impeller's rotation plane.

9. The lifetime prediction method according to claim 7, characterized in that, The prediction of the pitch system lifespan based on the frictional torque includes: The outer ring torque of the pitch bearing is determined based on the frictional torque. Using the outer ring torque as the boundary load, the dynamic load of the first component in the pitch system is determined; Rainflow statistics are performed on the dynamic load to determine the fatigue load information of the pitch system; Based on the fatigue load information, the fatigue damage and lifespan of the pitch system are determined. The lifetime prediction method further includes: Using the outer ring torque as the boundary load, determine the ultimate load of the second component in the pitch system; Based on the ultimate load, the safety margin of the pitch system and the driving torque margin of the drive device in the pitch system are determined.

10. An electronic device, characterized in that, The electronic device includes: processor; Memory used to store the processor's executable instructions. When the processor executes the executable instructions, it causes the processor to perform the method for determining the friction torque calculation model of the pitch bearing according to any one of claims 1 to 7 or the method for predicting the life of the pitch system of the wind turbine generator according to claim 8.

11. A computer-readable storage medium, characterized in that, When the instructions in the computer-readable storage medium are executed by the processor of the electronic device, the electronic device is able to perform the method for determining the friction torque calculation model of the pitch bearing according to any one of claims 1 to 7 or the method for predicting the life of the pitch system of the wind turbine generator according to claim 8.

12. A computer program product comprising computer-executable instructions, characterized in that, When the computer-executable instructions are executed by at least one processor, they implement the method for determining the friction torque calculation model of the pitch bearing according to any one of claims 1 to 7, or the method for predicting the life of the pitch system of a wind turbine generator according to claim 8.

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