Variable pitch control method and system of wind generating set and wind generating set

Abstract

The invention provides a variable pitch control method and system of a wind generating set and the wind generating set. The variable pitch control method comprises the steps that wind speed data at the wind coming side of an impeller of the wind generating set and at the position away from the impeller by a preset distance in the current control period are determined; determining an estimated pitch angle of the current control period based on the wind speed data of the current control period; comparing the estimated pitch angle of the current control period with the reference pitch angle of the previous control period, and taking the comparison result as the reference pitch angle of the current control period; and on the basis of the reference pitch angle of the current control period, blade pitch variation of the wind generating set is controlled. According to the variable pitch control method of the wind generating set and the wind generating set, the problem that the reduction effect of the fatigue load of the whole machine is poor due to control hysteresis is solved, blade variable pitch can be controlled in advance, and the limit load and the fatigue load of the whole machine are better reduced.

Description

Technical Field

[0001] The present disclosure relates to the field of wind power generation, and more specifically, to a variable pitch control method and system for a wind generator set and a wind generator set. Background Art

[0002] As the impeller diameter and overall capacity of wind turbines increase, the overall cost is more constrained. The traditional control method of wind turbines is based on proportional-integral-derivative (PID) control technology.

[0003] In the control process of the relevant technology, when the wind speed acts on the blades of the wind turbine and causes the impeller speed to change, the PID controller performs closed-loop control based on the deviation between the speed control target value and the actual speed value. Such a process will have a control lag, making it difficult to control the ultimate load of the unit well, and the load reduction effect on the fatigue load of the entire machine is also poor. Summary of the invention

[0004] In view of the problem that the pitch control in the related art has a hysteresis which leads to poor stability of the impeller speed and poor effect of reducing the fatigue load of the whole machine, the present disclosure provides a pitch control method and system for a wind turbine and a wind turbine.

[0005] A first aspect of the present disclosure provides a pitch control method for a wind turbine generator set, the pitch control method comprising at least one control stage, each control stage comprising a plurality of control cycles, wherein, for any control cycle in any control stage, the pitch control method comprises: determining wind speed data at a preset distance from the impeller on the windward side of the impeller of the wind turbine generator set in a current control cycle; determining an estimated pitch angle of the current control cycle based on the wind speed data of the current control cycle; comparing the estimated pitch angle of the current control cycle with a reference pitch angle of a previous control cycle, and using the compared result as a reference pitch angle of the current control cycle; and controlling the pitch of blades of the wind turbine generator set based on the reference pitch angle of the current control cycle.

[0006] Optionally, for any control stage, the variable pitch control method also includes: determining the number of cycles of the current control stage based on the statistical wind speed before the initial moment of the initial control cycle of the current control stage, the preset distance and the duration of each control cycle; in response to the number of control cycles in the current control stage reaching the number of cycles, entering the next control stage.

[0007] Optionally, the statistical wind speed is determined in the following manner: obtaining the wind speed at multiple moments at the preset distance within a preset time period before the initial moment of the initial control cycle of the current control stage; and taking the statistical values ​​of the wind speed at the multiple moments as the statistical wind speed.

[0008] Optionally, the estimated pitch angle of the current control cycle is determined in the following manner: based on wind speed data of the current control cycle and air density of an environment in which the wind turbine generator set is located, the estimated pitch angle of the current control cycle is determined.

[0009] Optionally, determining the estimated pitch angle of the current control cycle based on the wind speed data of the current control cycle and the air density of the environment in which the wind turbine generator set is located includes: based on the current air density of the environment in which the wind turbine generator set is located, correcting a preset wind speed pitch angle model to obtain a corrected wind speed pitch angle model; inputting the wind speed data of the current control cycle into the corrected wind speed pitch angle model to obtain the estimated pitch angle of the current control cycle, wherein the preset wind speed pitch angle model characterizes the relationship between the wind speed and the pitch angle under a reference air density, and the corrected wind speed pitch angle model characterizes the relationship between the wind speed and the pitch angle under the current air density.

[0010] Optionally, the wind speed and pitch angle model is determined in the following manner: determining a first relationship between wind speed and pitch angle under a reference air density; determining a second relationship between the current air density and the reference air density based on the relationship between the active power, wind speed and air density of the wind turbine generator set; and determining the wind speed and pitch angle model based on the first relationship and the second relationship.

[0011] Optionally, the second relationship is determined in the following manner: determining a first power relationship between the active power and the wind speed of the wind turbine generator set at the reference air density; determining a second power relationship between the active power and the wind speed of the wind turbine generator set at the current air density; and determining the second relationship based on the first power relationship and the second power relationship by keeping the active power unchanged.

[0012] Optionally, in an initial control cycle of a current control phase, the estimated pitch angle of the initial control cycle is used as a reference pitch angle of the initial control cycle.

[0013] A second aspect of the present disclosure provides a pitch control system for a wind turbine generator set, the pitch control system comprising: a processor; and a memory for storing instructions executable by the processor, wherein the processor executable instructions, when executed by the processor, prompt the processor to execute the pitch control method for the wind turbine generator set according to the present disclosure.

[0014] A third aspect of the present disclosure provides a wind turbine generator set, wherein the wind turbine generator set comprises a pitch control system of the wind turbine generator set according to the present disclosure.

[0015] A fourth aspect of the present disclosure provides a computer-readable storage medium. When instructions in the computer-readable storage medium are executed by a processor of an electronic device, the electronic device is enabled to execute the pitch control method of a wind turbine generator set according to the present disclosure.

[0016] A fifth aspect of the present disclosure provides a computer program product, comprising computer executable instructions, which, when executed by at least one processor, implement the variable pitch control method of the wind turbine generator set according to the present disclosure.

[0017] According to the variable pitch control method, system and wind turbine of the wind turbine generator set disclosed in the present invention, the wind speed data at the windward side of the impeller of the wind turbine generator set at a preset distance from the impeller can be determined in the current control cycle, and the estimated pitch angle is obtained based on the wind speed data, and compared with the reference pitch angle of the previous control cycle to determine the reference pitch angle of the current control cycle. In this way, the estimated pitch angle corresponding to the wind speed data at a predetermined distance in front of the impeller can be estimated, and the final reference pitch angle of the current control cycle can be comprehensively determined in consideration of the reference pitch angle of the previous control cycle and the estimated pitch angle of the current control cycle to control the blade pitch change, so that the high load problem of the unit caused by the control lag can be solved or at least alleviated, the blade pitch change can be controlled in advance, and the limit load and fatigue load of the whole machine can be better reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Detailed description is a schematic flowchart illustrating a pitch control method of a wind turbine generator system according to an exemplary embodiment of the present disclosure.

[0019] Figure 2 is a schematic diagram showing determination of wind speed data in a pitch control method of a wind turbine generator set according to an exemplary embodiment of the present disclosure.

[0020] Figure 3 is a schematic flow chart showing steps of determining a wind speed pitch angle model in a pitch control method of a wind turbine generator system according to an exemplary embodiment of the present disclosure.

[0021] Figure 4 Schematic diagram showing a wind speed pitch angle model in a pitch control method of a wind turbine generator system according to an exemplary embodiment of the present disclosure.

[0022] Figure 5is a schematic flow chart showing the determination of a second relationship in a pitch control method of a wind turbine generator system according to an exemplary embodiment of the present disclosure.

[0023] Figure 6 is a schematic diagram showing a wind speed pitch angle correction model in a pitch control method of a wind turbine generator system according to an exemplary embodiment of the present disclosure.

[0024] Figure 7 Schematic diagram showing pitch angle variation in a pitch control method of a wind turbine generator set according to an exemplary embodiment of the present disclosure.

[0025] Fig. 8A , Figure 8B , Figure 8C and Fig.8D It is a schematic diagram showing the effect of the pitch control method of a wind turbine generator set according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0026] The following specific embodiments are provided to help the reader obtain a comprehensive understanding of the methods, devices and / or systems described herein. However, after understanding the disclosure of the present application, various changes, modifications and equivalents of the methods, devices and / or systems described herein will be clear. For example, the order of operations described herein is only an example and is not limited to those orders set forth herein, but can be changed as will be clear after understanding the disclosure of the present application, except for operations that must occur in a specific order. In addition, for greater clarity and simplicity, the description of features known in the art may be omitted.

[0027] The features described herein can be implemented in different forms and should not be construed as being limited to the examples described herein. Rather, the examples described herein have been provided to illustrate only some of the many possible ways to implement the methods, devices, and / or systems described herein, which will be clear after understanding the disclosure of the present 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 members, components, regions, layers, or portions, these members, components, regions, layers, or portions should not be limited by these terms. Instead, these terms are only used to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Therefore, without departing from the teachings of the examples described herein, the first member, first component, first region, first layer, or first portion referred to in the examples may also be referred to as the second member, second component, second region, second layer, or second portion.

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

[0031] The terms used herein are only used to describe various examples and are not intended to limit the disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms "comprise", "include" and "have" indicate the presence of the described features, quantities, operations, components, elements and / or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, operations, components, elements and / or combinations thereof.

[0032] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by a person of ordinary skill in the art to which the present disclosure belongs after understanding the present disclosure. Unless explicitly defined as such herein, terms (such as those defined in a general dictionary) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and the present disclosure, and should not be interpreted in an idealized or overly formal manner.

[0033] Furthermore, in the description of examples, when it is considered that a detailed description of a well-known related structure or function would cause vague interpretation of the present disclosure, such a detailed description will be omitted.

[0034] In view of the problems mentioned above, the present disclosure provides a pitch control method of a wind turbine generator set, a pitch control system of a wind turbine generator set, a wind turbine generator set, a computer-readable storage medium and a computer program product to solve or at least alleviate the above problems.

[0035] According to a first aspect of an exemplary embodiment of the present disclosure, a pitch control method of a wind turbine is provided. The pitch control method can be executed by a computer device having computing capabilities, for example, by a computer device in a pitch control system of a wind turbine. The computer device executing the pitch control method can be, for example, a terminal device or a server, wherein the terminal device can be, for example, a tablet computer, a laptop computer, a digital assistant, etc.; the server can be an independent server, a server cluster, a cloud computing platform, or a virtualization center.

[0036] Here, the computer device can be set at a wind turbine or wind farm, for example, and can be communicatively connected to a measuring device or data center of the wind turbine or wind farm, so as to obtain the data required to execute the above method, such as measuring wind speed.

[0037] In an embodiment of the present disclosure, a pitch control method of a wind turbine generator set may include at least one control stage, each control stage may include multiple control cycles, and for any control cycle in any control stage, the pitch control method may include the following steps:

[0038] like Figure 1 As shown, in step S110, the wind speed data at a preset distance from the impeller on the incoming wind side of the impeller of the wind turbine generator set in the current control cycle can be determined.

[0039] In this step, the preset distance can be set according to actual needs. As an example, the wind speed at the preset distance can be measured by wind measuring equipment such as laser radar, millimeter wave ranging radar, microwave radar, sodar, etc., and the above wind speed data is determined based on the measured wind speed. However, the embodiments of the present disclosure are not limited to this, and the wind speed can also be obtained by other devices or methods, for example, it can also be estimated by a machine learning model or an empirical model.

[0040] Specifically, taking the use of LiDAR to measure wind speed as an example, the LiDAR can be installed on the nacelle or the hub, such as Figure 2 As shown, the lidar sensor may include four light beams such as LOS1, LOS2, LOS3 and LOS4, along which multiple sections may be measured simultaneously, and the distances between different sections and the impeller may be different. For example, the distance between the first section P1 and the impeller may be d1, and the distance between the second section P2 and the impeller may be d2.

[0041] In the process of wind blowing from the windward side to the impeller, the wind speed may vary. Here, multiple wind speeds of the cross section at a preset distance from the impeller can be obtained by the laser radar, for example, the wind speed measured by the light beams LOS1, LOS2, LOS3 and LOS4 at the first cross section P1 can be obtained. At this time, the preset distance D is d1. In the current control cycle, the wind speed data at the preset distance can be: the average value of the wind speed in the cross section at the preset distance at the initial moment of the current control cycle, for example, the average value of the wind speed measured by the light beams LOS1, LOS2, LOS3 and LOS4 at the first cross section P1.

[0042] In the above example, the radar-based feedforward control technology can measure the wind speed in front of the impeller in advance through the radar hardware sensor, and control the pitch angle change of the wind turbine to match the pulsation change of the wind speed in real time. According to experience, radar feedforward control has a good effect on controlling the speed stability of the impeller and reducing the fatigue load of the whole machine. However, the embodiments of the present disclosure are not limited to this. As mentioned above, other wind measuring equipment or software models can also be used to determine the wind speed.

[0043] It should be noted that in the above examples, there is no rigid requirement on the number of wind measurement beams and wind measurement distance sections of the laser radar. For example, multiple preset distances (such as Figure 2 The wind speed data can be statistically analyzed at the first distance d1 and the second distance d2 shown in the figure, or the measured wind speed at the preset distance can be directly used as the wind speed data in this step, as long as the wind speed data can characterize the wind speed conditions in front of the impeller (or the wind side), so as to achieve early control of pitch by measuring the wind in advance.

[0044] Return to reference Figure 1 In step S120, an estimated pitch angle of the current control cycle may be determined based on the wind speed data of the current control cycle.

[0045] In this step, the estimated pitch angle may refer to the pitch angle calculated according to the wind speed data. In some examples, an existing variable pitch control algorithm may be used to calculate the corresponding pitch angle as the above-mentioned estimated pitch angle based on the wind speed data obtained in step S110. The following embodiment of the present disclosure will give an example of determining the estimated pitch angle.

[0046] Specifically, the estimated pitch angle of the current control cycle may be determined in the following manner: based on the wind speed data of the current control cycle and the air density of the environment in which the wind turbine generator set is located, the estimated pitch angle of the current control cycle is determined.

[0047] Under different air densities, different loads may be imposed on the unit even if the wind speed is the same. Therefore, the embodiments of the present disclosure use both wind speed data and air density as input quantities for calculating the pitch angle to achieve more precise pitch control and improve the load reduction effect of the unit.

[0048] As an example, the relationship among wind speed data, air density and pitch angle can be calculated by simulation. For example, the optimal pitch angle corresponding to different wind speed data and different air densities can be simulated while satisfying the power generation power and load requirements of the unit, and a relationship curve or relationship table among the three can be obtained. In actual control, based on the wind speed data obtained in step S110 and the current air density, the estimated pitch angle can be obtained by searching the preset relationship curve or relationship table.

[0049] As another example, the estimated pitch angle can be determined by constructing a wind speed pitch angle model. Specifically, in this example, the estimated pitch angle of the current control cycle can be determined by inputting the wind speed data and air density of the current control cycle into the wind speed pitch angle model to obtain the estimated pitch angle of the current control cycle.

[0050] The wind speed and pitch angle model can characterize the relationship between wind speed and pitch angle under the current air density.

[0051] In this regard, in one example, a machine learning model can be pre-trained based on historical wind speed samples, historical air density samples and corresponding pitch angles. In actual control, the wind speed data and current air density of the current control cycle can be input into the trained machine learning model, and the pitch angle can be estimated through the model output.

[0052] In another example, considering that a wind turbine is a complex nonlinear model, it is difficult to directly construct a high-order model with a high degree of compliance. The method of obtaining a relationship curve or relationship table through simulation requires a large number of data points, and the method of training a machine learning model also requires a high number and quality of samples. Therefore, these methods may generate a large amount of preliminary work. In this regard, the embodiment of the present disclosure also provides a method of determining an estimated pitch angle by constructing a low-order model and correcting the model to perform the next step of pitch angle control.

[0053] In this example, based on the air density, the preset wind speed pitch angle model is corrected to obtain a corrected wind speed pitch angle model; the wind speed data of the current control cycle is input into the corrected wind speed pitch angle model to obtain the estimated pitch angle of the current control cycle. Here, the preset wind speed pitch angle model represents the relationship between the wind speed and the pitch angle under the reference air density, and the corrected wind speed pitch angle model represents the relationship between the wind speed and the pitch angle under the current air density.

[0054] Specifically, the wind speed pitch angle model under the reference air density can be obtained, and the wind speed pitch angle model under the current air density can be obtained by correcting the wind speed pitch angle model. As an example, the wind speed pitch angle model can be determined in the following way:

[0055] like Figure 3 As shown, in step S310, a first relationship between wind speed and pitch angle under a reference air density may be determined.

[0056] Here, the reference air density may be, for example, a standard air density. Specifically, during the design of a wind turbine generator set, the standard air density is used to perform simulation calculations of the set, so that after the set design is completed, the relationship between the wind speed and pitch angle under the standard air density can be obtained.

[0057] For example, the first relationship between the wind speed and the pitch angle of the unit under standard air density can be obtained by simulation software such as DNV Bladed or NREL FAST, for example: Figure 4 The first relationship may be a first wind speed pitch angle model under a reference air density, for example, it may be represented by θ=f(V), wherein θ represents the pitch angle of the whole machine under different wind speeds, and f() represents the relationship of the pitch angle based on the wind speed under the reference air density.

[0058] Here, the optimal pitch angle may be the minimum pitch angle of the wind turbine generator set determined during the design process. The wind speed pitch angle curve of the first relationship may be a curve calculated based on the blade performance and overall machine loss of the wind turbine generator set, and the minimum pitch angle in the curve is the optimal pitch angle.

[0059] In step S320, a second relationship between the current air density and the reference air density may be determined based on the relationship between the active power of the wind turbine generator set, the wind speed, and the air density.

[0060] In this step, the second relationship may be used to convert between the current air density and the reference air density, so as to obtain a wind speed and pitch angle model under the current air density based on the first relationship.

[0061] As an example, the second relationship can be determined by a power calculation expression that characterizes the power generation performance of the entire machine. In this way, the second relationship can be obtained through the relationship between different air densities at the same power, and thus the wind speed and pitch angle model at the current air density can be quickly and easily obtained by converting the current air density with the reference air density.

[0062] For example, the second relationship can be determined as follows:

[0063] like Figure 5 As described above, in step S510, a first power relationship between the active power and the wind speed of the wind turbine generator set under a reference air density may be determined.

[0064] Specifically, the first power relationship between the active power of the wind turbine generator set and the wind speed under the reference air density can be expressed by the following formula (1):

[0065]

[0066] Among them, ρ0 represents the reference air density, such as the air density under standard conditions (such as 0°C and 1 standard atmospheric pressure); R represents the radius of the wind turbine impeller, V represents the wind speed, Cp represents the wind energy utilization coefficient, and P represents the active power of the wind turbine under the reference air density, such as the actual active power.

[0067] In step S520, a second power relationship between the active power of the wind turbine generator set and the wind speed under the current air density may be determined.

[0068] In actual situations, air density and wind speed vary with factors such as geographical location, sea waves and terrain. Therefore, the second power relationship between the active power of the wind turbine generator set and the wind speed under the current air density can be expressed by the following formula (2):

[0069]

[0070] Where ρ represents the current air density, P ′ It represents the active power of the wind turbine generator set under the current air density. Here, the current air density may be the real-time air density during the control process, for example, obtained by real-time measurement by a measuring device.

[0071] In step S530, the second relationship may be determined based on the first power relationship and the second power relationship by keeping the active power unchanged.

[0072] In this step, for the above-mentioned first power relationship and second power relationship, due to different air densities, if it is desired to keep the active power unchanged, the second power relationship needs to be adjusted. In the second power relationship, the variable is the wind speed. Therefore, the active power can be kept unchanged by weighting the wind speed in the second power relationship.

[0073] Specifically, it can be assumed that the weighted wind speed is V1. Under the weighted wind speed representation, the active power of the first power relationship and the second power relationship can remain unchanged, thereby obtaining the following formula (3):

[0074]

[0075] Based on the above formula (3), the second relationship can be obtained as shown in the following formula (4):

[0076] ρ0V 3 =ρV1 3 (4)

[0077] Furthermore, the weighted wind speed can be obtained: It can be obtained that when the air density changes from the reference air density to the current air density, if the active power remains unchanged, the required change in wind speed is

[0078] In step S330, a wind speed pitch angle model may be determined based on the first relationship and the second relationship.

[0079] Since the performance curve of the whole machine (the relationship curve between wind speed and pitch angle) will shift under different air densities, the relationship curve under the current air density can be obtained by shifting left or right based on the relationship curve under the reference air density.

[0080] As an example, the wind speed pitch angle model under the reference air density can be expressed by the first relationship θ=f(V). Based on the second relationship of the above formula (4), the first relationship can be corrected to obtain the wind speed pitch angle model under the current air density, which can be expressed as For example, the current air density ρ = 1.0 kg / m 3 For example, based on Figure 4 , the models before and after correction are obtained as Figure 6 shown.

[0081] In the above manner, starting from the power generation performance of the unit, by keeping the active power unchanged, the conversion relationship for air density can be obtained, so that the wind speed pitch angle model under any current air density can be corrected based on the wind speed pitch angle model under the reference air density.

[0082] It should be noted that, although the process of determining the wind speed and pitch angle model is described above with reference to various formulas, the embodiments of the present disclosure are not limited thereto, and the power generation performance of the unit can also be expressed in other ways. For example, the above formula (1) can be expressed in other forms, as long as the relationship between the power generation performance parameters (such as the above-mentioned active power), air density and wind speed can be established and the first relationship can be corrected based on the relationship.

[0083] Return to reference Figure 1 In step S130, the estimated pitch angle of the current control cycle may be compared with the reference pitch angle of the previous control cycle, and the comparison result may be used as the reference pitch angle of the current control cycle.

[0084] In some cases, the pitch angle calculated according to the wind speed can be directly output as a reference pitch angle to control the pitch change. Here, in the embodiments of the present disclosure, it is not only considered that the pitch change can be controlled in advance by measuring the wind in advance, but also that in the case of measuring the wind in advance, a larger pitch angle can be always maintained before the wind reaches the impeller, thereby ensuring the effect of the early pitch change on the load reduction of the unit.

[0085] For example, in step S130, the larger of the estimated pitch angle of the current control cycle and the reference pitch angle of the previous control cycle can be used as the reference pitch angle of the current control cycle. Specifically, in response to the estimated pitch angle of the current control cycle being greater than or equal to the reference pitch angle of the previous control cycle, the estimated pitch angle of the current control cycle is used as the reference pitch angle of the current control cycle; in response to the estimated pitch angle of the current control cycle being less than the reference pitch angle of the previous control cycle, the reference pitch angle of the previous control cycle is used as the reference pitch angle of the current control cycle.

[0086] Here, in the initial control cycle of the current control stage, the estimated pitch angle of the initial control cycle may be used as the reference pitch angle of the initial control cycle.

[0087] As an example, it is assumed that the duration of one control cycle of the wind turbine generator set is Δt. Here, Δt can be set according to actual needs, for example, it can be 10ms or 20ms.

[0088] In the initial control cycle of any control stage (e.g., marked as time 0), the estimated pitch angle θ(0) of the control cycle (time 0) is obtained according to the wind speed data of the initial control cycle, for example, through the modified model, and the final reference pitch angle (or pitch angle demand value) θ is output. dmd (0) = θ(0).

[0089] In the next control cycle (for example, recorded as time 0+Δt), the estimated pitch angle θ(0+Δt) of the control cycle (time 0+Δt) is obtained according to the wind speed data of the cycle, for example, through the corrected model.

[0090] Here, in response to the estimated pitch angle θ(0+Δt) of the current control cycle being greater than or equal to the reference pitch angle θ of the previous control cycle, dmd (0), then the reference pitch angle θ of the current control cycle is dmd (0+△t)=θ(0+△t); in response to the estimated pitch angle θ(0+△t) of the current control cycle being less than the reference pitch angle θ of the previous control cycle dmd (0), then the reference pitch angle θ of the current control cycle is dmd (0+△t)=θ dmd (0).

[0091] In step S140, the blade pitch of the wind turbine generator set may be controlled based on the reference pitch angle of the current control cycle.

[0092] When the reference pitch angle of the current control cycle is determined, the blade pitch of the wind turbine generator set can be controlled, so that the blade pitch angle can be adjusted to the required position in advance by utilizing advance wind measurement, thereby achieving the purpose of load reduction.

[0093] In an embodiment of the present disclosure, the control process may include at least one control stage, and each control cycle in each control stage may perform pitch control in the above-mentioned manner. Here, in the case of including multiple control stages, in one example, the control stages may be switched according to preset timing intervals.

[0094] In another example, each control stage can be determined based on the advance time of wind measurement. Specifically, for any control stage, the pitch control method can also include: determining the number of cycles of the current control stage according to the statistical wind speed before the initial moment of the initial control cycle of the current control stage, the preset distance, and the duration of each control cycle; in response to the number of control cycles in the current control stage reaching the number of cycles, entering the next control stage.

[0095] As an example, the statistical wind speed can be determined in the following manner: obtain the wind speed at multiple moments at a preset distance within a preset time period before the initial moment of the initial control cycle of the current control stage; and use the statistical values ​​of the wind speed at multiple moments as the statistical wind speed of the initial control cycle.

[0096] In this example, for the measured wind speed at the preset distance D, the initial moment of the initial control cycle can be taken as the starting point, and the historical measured wind speeds at multiple moments within a period of time before the initial moment can be statistically analyzed (for example, averaged) according to a preset time period to obtain the above statistical wind speed.

[0097] As an example, the preset time period may be a preset sliding time window, and each time the statistical wind speed is calculated (for example, when the statistical wind speed is calculated at the initial moment of each control stage), the wind speed statistics at multiple moments may be performed forward according to the sliding time window for the moment when the statistical wind speed is to be calculated, so as to obtain the statistical wind speed. The preset time period may be set according to actual needs, for example, may be 100 seconds.

[0098] In the above example, the statistical wind speed is determined by statistically analyzing the wind speed at multiple time points. The statistical value of the wind speed can be used to more accurately judge the current wind conditions and the travel time for the wind to reach the impeller, thereby more accurately determining the number of cycles in the current control stage and performing pitch changes in advance.

[0099] Specifically, assuming that the wind speed in front of the impeller satisfies the frozen rotor hypothesis, and the wind advances according to the statistical wind speed obtained above, the advance time T of the measured impeller wind speed reaching the impeller can be obtained, T = D / U, where D is the preset distance mentioned above, and U is the statistical wind speed. In this regard, it can be considered that for the statistical wind speed U at the preset distance D, starting from the initial moment of any control stage, after time T, the wind at the preset distance D will reach the impeller surface, so this time T can be used as the duration of a control stage.

[0100] As an example, the above steps S110 to S140 may be performed N times, so the control stage may include N control cycles, and the number of cycles may represent the number of control cycles experienced by the unit during the time period when the wind reaches the impeller from the preset distance. For example, the number of cycles N may be represented by the following formula (5):

[0101] N=T / Δt (5)

[0102] In any control stage, the above steps S110 to S140 can be executed in a rolling manner until the number of control cycles in the control stage reaches the number of cycles. Assuming that the starting time of the initial control cycle is time 0, when the starting time of the current control cycle is time 0+N△t, the reference pitch angle θ of the control cycle can be updated. dmd (0+N*△t)=θ(0+N*△t), this control period can be used as the initial control period of the next control stage.

[0103] In this way, the duration and number of cycles of each control stage can be reasonably set, so that in the process of wind moving from a preset distance to the impeller, the pitch angle state that can cope with the wind speed is always maintained, thereby reducing the load on the unit when the wind speed comes.

[0104] Figure 7 The change of the pitch angle during the pitch control process using the above control method is shown in FIG. Figure 7 As shown, in each control stage, the reference pitch angle can always be maintained at a high level so as to be able to cope with the wind that is about to reach the rotor.

[0105] The following will be combined FIG. 8A to FIG. 8D An example effect of adopting the pitch control method according to an embodiment of the present disclosure is shown.

[0106] Taking a real wind turbine as an example, after adopting the above method for control, Fig. 8A As shown, for the blade root limit load, the bending moment load My around the y-axis of the blade root coordinate system is reduced by 3.5%, the bending moment load Mz around the z-axis of the blade root coordinate system is reduced by 3.9%, and the combined load Mxy of the x-axis and y-axis is reduced by 4.2%; Figure 8B As shown in Figure 2, for the ultimate load at the bottom of the tower, the moment load My is reduced by 4.7%, the moment load Mz is reduced by 1.3%, and the combined load Mxy is reduced by 4.3%. Figure 8C As shown in Figure 2, for blade root fatigue load, the bending moment load My is reduced by 1.0% and the bending moment load Mz is reduced by 3.1%. Fig.8D As shown, for the fatigue load at the bottom of the tower, the moment load My is reduced by 1.1%. Figure 8C and Fig.8DIn the figure, m represents the m value (also called Wohler index) in the SN curve of the material fatigue life characteristics, which represents the relationship between the stress level and the fatigue life in the SN curve. For different materials, the m value is different. For example, the m value of the blade can be 9 or 4.

[0107] According to the variable pitch control method of the wind turbine generator set disclosed in the present invention, the wind speed data in front of the impeller can be obtained in advance, and the pitch angle can be adjusted in advance to the expected pitch angle position corresponding to the incoming wind speed, thereby reducing the critical limit loads of multiple components such as the blade root, tower top and tower bottom, and achieving cost optimization of key components of the wind turbine set.

[0108] According to a second aspect of an embodiment of the present disclosure, a pitch control system of a wind turbine is provided, the pitch control system comprising: a processor; and a memory for storing processor executable instructions, wherein the processor executable instructions, when executed by the processor, prompt the processor to execute the pitch control method of the wind turbine described in the embodiment of the present disclosure.

[0109] As an example, the variable pitch control system may include a wind measurement and collection module, a model building module, and a pitch angle control module. Here, the wind measurement and collection module is used to determine the wind speed data at a preset distance from the impeller on the windward side of the impeller of the wind turbine generator set. The model building module is used to determine the estimated pitch angle based on the wind speed data, for example, according to the overall performance curve of the wind turbine generator set, to determine the estimated pitch angle, and by comparing the estimated pitch angle of the current control cycle with the reference pitch angle of the previous control cycle, the compared result is used as the reference pitch angle of the current control cycle. The pitch angle control module is used to execute the pitch angle control requirement based on the reference pitch angle.

[0110] The pitch control system may include a computer device. Specifically, the pitch control method of the wind turbine generator set may be executed by the computer device.

[0111] As an example, the computer device can be a PC, a tablet device, a personal digital assistant, a smart phone, or other device capable of executing the above-mentioned instruction set. Here, the computer device is not necessarily a single electronic device, but can also be any device or circuit that can execute the above-mentioned instructions (or instruction sets) individually or jointly. The computer device can also be part of an integrated control system or system manager, or can be configured as a portable electronic device that is interconnected with a local or remote (e.g., via wireless transmission) interface.

[0112] In a computer device, 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. As an example and not limitation, a processor may also include an analog processor, a digital processor, a microprocessor, a multi-core processor, a processor array, a network processor, etc.

[0113] The processor can execute instructions or codes stored in the memory, wherein the memory can also store data. Instructions and data can also be sent and received through the network via the network interface device, wherein the network interface device can adopt any known transmission protocol.

[0114] The memory may be integrated with the processor, for example, RAM or flash memory is arranged within an integrated circuit microprocessor or the like. In addition, the memory may include a separate device, such as an external disk drive, a storage array, or any other storage device that can be used by a database system. The memory and the processor may be operatively coupled, or may communicate with each other, such as through an I / O port, a network connection, etc., so that the processor can read files stored in the memory.

[0115] In addition, the computer device may also include a video display (such as a liquid crystal display) and a user interaction interface (such as a keyboard, a mouse, a touch input device, etc.) All components of the computer device may be connected to each other via a bus and / or a network.

[0116] According to a third aspect of an embodiment of the present disclosure, a wind turbine generator set is provided, and the wind turbine generator set includes a pitch control system of the wind turbine generator set according to an embodiment of the present disclosure.

[0117] According to a fourth aspect of an embodiment of the present disclosure, a computer-readable storage medium is provided. When instructions in the computer-readable storage medium are executed by a processor of an electronic device, the electronic device is enabled to execute the variable pitch control method of a wind turbine generator set according to an embodiment of the present disclosure.

[0118] Specifically, the pitch control method of a wind turbine generator set according to an embodiment of the present disclosure can be written as 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 prompted to execute the pitch control method of the wind turbine generator set according to the exemplary embodiment of the present 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 disk storage, hard disk drive (HDD), solid state drive (SSD), card storage (such as, multimedia card, secure digital (SD) card or extreme digital (XD) card), magnetic tape, floppy disk, magneto-optical data storage device, optical data storage device, hard disk, solid state disk and any other device, any other device is configured to store computer program and any associated data, data files and data structures in a non-transitory manner and provide the computer program and any associated data, data files and data structures to a processor or computer so that the processor or computer can execute the computer program. In one example, the computer program and any associated data, data files and data structures are distributed on a networked computer system so that the computer program and any associated data, data files and data structures are stored, accessed and executed in a distributed manner by one or more processors or computers.

[0119] According to a fifth aspect of an embodiment of the present disclosure, a computer program product is provided, which includes computer executable instructions. When the computer executable instructions are executed by at least one processor, the variable pitch control method of the wind turbine generator set according to the embodiment of the present disclosure is implemented.

[0120] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. The present disclosure is intended to cover any variations, uses or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The description and examples are to be considered exemplary only, and the true scope and spirit of the present disclosure are indicated by the claims.

[0121] In addition, it should be noted that although several examples of each step are described above with reference to specific drawings, it should be understood that the embodiments of the present disclosure are not limited to the combinations given in the examples, and the steps appearing in different drawings may be combined, and the order of execution of the steps may be changed, which is not exhaustive here.

[0122] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

[0123] The specific implementation methods of the present disclosure have been described in detail above. Although some embodiments have been shown and described, those skilled in the art should understand that these embodiments may be modified and varied without departing from the principles and spirit of the present disclosure, the scope of which is defined by the claims and their equivalents. These modifications and variations should also be within the scope of protection of the claims of the present disclosure.

Claims

1. A variable pitch control method for a wind turbine generator set, characterized in that: The pitch control method includes at least one control stage, each control stage includes a plurality of control cycles, wherein for any control cycle in any control stage, the pitch control method includes: Determine wind speed data at a preset distance from the impeller on the windward side of the impeller of the wind turbine generator set in the current control cycle; Determining an estimated pitch angle for the current control period based on wind speed data for the current control period; Comparing the estimated pitch angle of the current control cycle with the reference pitch angle of the previous control cycle, and using the comparison result as the reference pitch angle of the current control cycle; The blade pitch of the wind turbine generator set is controlled based on the reference pitch angle of the current control cycle.

2. The pitch control method according to claim 1, characterized in that: For any control stage, the pitch control method further includes: Determine the number of cycles in the current control phase according to the statistical wind speed before the initial moment of the initial control cycle of the current control phase, the preset distance, and the duration of each control cycle; In response to the number of control cycles in the current control phase reaching the number of cycles, entering the next control phase.

3. The pitch control method according to claim 2, characterized in that: The statistical wind speed is determined by: Acquire wind speeds at multiple moments at the preset distance within a preset time period before an initial moment of an initial control cycle of a current control stage; The statistical values ​​of the wind speeds at the multiple moments are used as the statistical wind speed.

4. The pitch control method according to any one of claims 1 to 3, characterized in that: The estimated pitch angle for the current control cycle is determined by: An estimated pitch angle of the current control cycle is determined based on the wind speed data of the current control cycle and the air density of the environment in which the wind turbine generator set is located.

5. The pitch control method according to claim 4, characterized in that: The step of determining the estimated pitch angle of the current control period based on the wind speed data of the current control period and the air density of the environment in which the wind turbine generator set is located comprises: Based on the current air density of the environment in which the wind turbine generator set is located, the preset wind speed pitch angle model is corrected to obtain a corrected wind speed pitch angle model; The wind speed data of the current control cycle is input into the modified wind speed pitch angle model to obtain the estimated pitch angle of the current control cycle. The preset wind speed pitch angle model represents the relationship between the wind speed and the pitch angle at a reference air density, and the modified wind speed pitch angle model represents the relationship between the wind speed and the pitch angle at the current air density.

6. The pitch control method according to claim 5, characterized in that: The wind speed pitch angle model is determined by: determining a first relationship between wind speed and pitch angle at a reference air density; Determining a second relationship between the current air density and the reference air density based on the relationship between the active power, wind speed and air density of the wind turbine generator set; The wind speed and pitch angle model is determined based on the first relationship and the second relationship.

7. The pitch control method according to claim 6, characterized in that: The second relationship is determined by: Determining a first power relationship between active power and wind speed of the wind turbine generator set at the reference air density; Determine a second power relationship between active power and wind speed of the wind turbine generator set under the current air density; The second relationship is determined based on the first power relationship and the second power relationship by keeping the active power unchanged.

8. The pitch control method according to claim 1, characterized in that: In an initial control cycle of a current control phase, the estimated pitch angle of the initial control cycle is used as a reference pitch angle of the initial control cycle.

9. A variable pitch control system for a wind turbine generator set, characterized in that: The pitch control system comprises: processor; a memory for storing instructions executable by the processor, Wherein, when the processor executable instructions are executed by the processor, the processor is prompted to execute the variable pitch control method for a wind turbine generator set according to any one of claims 1 to 8.

10. A wind turbine generator set, characterized in that: The wind turbine generator set comprises the pitch control system of the wind turbine generator set according to claim 9.

11. A computer-readable storage medium, characterized in that: When the instructions in the computer-readable storage medium are executed by a processor of an electronic device, the electronic device is enabled to execute the pitch control method for a wind turbine generator set according to any one of claims 1 to 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, the pitch control method of a wind turbine generator set according to any one of claims 1 to 8 is implemented.

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