Variable pitch control method, system and wind turbine for a wind turbine
By measuring wind speed data in front of the wind turbine rotor, calculating and comparing the pitch angle, pitch control of the wind turbine was realized, solving the problems of unstable speed and fatigue load caused by control lag in traditional methods, and reducing the overall load of the machine.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING GOLDWIND SCI & CREATION WINDPOWER EQUIP CO LTD
- Filing Date
- 2024-12-11
- Publication Date
- 2026-05-22
Smart Images
Figure CN119593947B_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of wind power generation, and more specifically, to a pitch control method, system, and wind turbine generator set. Background Technology
[0002] As the rotor diameter and overall capacity of wind turbine generators increase, the overall cost becomes a significant constraint. Traditional wind turbine generator control methods are based on proportional-integral-derivative (PID) control technology.
[0003] In the control process of related technologies, when the wind speed acts on the blades of the wind turbine generator and causes the rotor speed to change, the PID controller performs closed-loop control based on the deviation between the target speed control value and the actual speed value. This process will have control lag, making it difficult to control the ultimate load of the unit well, and the effect of reducing the fatigue load of the whole machine is also not good. Summary of the Invention
[0004] In view of the problems in the pitch control of related technologies, such as the lag in control leading to poor stability of rotor speed and poor effect on reducing fatigue load of the whole machine, this disclosure provides a pitch control method, system and wind turbine generator set.
[0005] The first aspect of this disclosure provides a pitch control method for a wind turbine generator set. The pitch control method includes at least one control stage, and each control stage includes multiple control cycles. For any control cycle within any control stage, the pitch control method includes: determining wind speed data at a preset distance from the rotor on the windward side of the wind turbine generator set during the current control cycle; determining an estimated pitch angle for the current control cycle based on the wind speed data; comparing the estimated pitch angle of the current control cycle with a reference pitch angle from the previous control cycle, and using the comparison result as the reference pitch angle for the current control cycle; and controlling the blades of the wind turbine generator set to pitch based on the reference pitch angle of the current control cycle.
[0006] Optionally, for any control phase, the pitch control method further includes: determining the number of cycles in the current control phase based on 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; and entering the next control phase in response to the number of control cycles in the current control phase reaching the number of cycles.
[0007] Optionally, the statistical wind speed is determined by: obtaining the wind speed at multiple times at the preset distance within a preset time period before the initial moment of the initial control cycle of the current control phase; and using the statistical value of the wind speed at the multiple times as the statistical wind speed.
[0008] Optionally, the estimated pitch angle for the current control cycle can be determined by: determining the estimated pitch angle for the current control cycle based on the wind speed data for the current control cycle and the air density of the environment in which the wind turbine is located.
[0009] Optionally, determining the estimated pitch angle for the current control period based on the wind speed data of the current control period and the air density of the environment where the wind turbine is located includes: modifying a preset wind speed pitch angle model based on the current air density of the environment where the wind turbine is located to obtain a modified wind speed pitch angle model; inputting the wind speed data of the current control period into the modified wind speed pitch angle model to obtain the estimated pitch angle for the current control period, wherein the preset wind speed pitch angle model represents the relationship between wind speed and pitch angle under a reference air density, and the modified wind speed pitch angle model represents the relationship between wind speed and pitch angle under the current air density.
[0010] Optionally, 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 of the wind turbine generator, wind speed, and air density; and determining the wind speed pitch angle model based on the first relationship and the second relationship.
[0011] Optionally, the second relationship is determined by: determining a first power relationship between the active power of the wind turbine generator set and the wind speed at the reference air density; determining a second power relationship between the active power of the wind turbine generator set and the wind speed at the current air density; and determining the second relationship based on the first power relationship and the second power relationship while keeping the active power constant.
[0012] Optionally, in the initial control cycle of the current control phase, the estimated pitch angle of the initial control cycle is used as the reference pitch angle of the initial control cycle.
[0013] A second aspect of this disclosure provides a pitch control system for a wind turbine generator set, 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, cause the processor to perform a pitch control method for the wind turbine generator set according to this disclosure.
[0014] A third aspect of this disclosure provides a wind turbine generator set, the wind turbine generator set including a pitch control system according to the present disclosure.
[0015] A fourth aspect of this disclosure provides a computer-readable storage medium that, when instructions in the computer-readable storage medium are executed by a processor of an electronic device, enables the electronic device to perform a pitch control method for a wind turbine generator according to this disclosure.
[0016] A fifth aspect of this disclosure provides a computer program product including computer-executable instructions that, when executed by at least one processor, implement the pitch control method for a wind turbine generator according to this disclosure.
[0017] According to the pitch control method, system, and wind turbine generator disclosed herein, in the current control cycle, wind speed data at a preset distance from the rotor on the windward side of the wind turbine generator can be determined. Based on this wind speed data, an estimated pitch angle is obtained and compared with the reference pitch angle of the previous control cycle to determine the reference pitch angle for the current control cycle. In this way, an estimated pitch angle corresponding to the wind speed data at a predetermined distance in front of the rotor can be predicted. Furthermore, considering both the reference pitch angle of the previous control cycle and the estimated pitch angle of the current control cycle, the final reference pitch angle for the current control cycle is comprehensively determined to control the blade pitch. This can solve or at least alleviate the high load problem caused by control lag, control blade pitch in advance, and better reduce the ultimate load and fatigue load of the entire unit. Attached Figure Description
[0018] Figure 1 This is a schematic flowchart illustrating a pitch control method for a wind turbine generator set according to an exemplary embodiment of the present disclosure.
[0019] Figure 2 This is a schematic diagram illustrating the determination of wind speed data in a pitch control method for a wind turbine generator according to an exemplary embodiment of the present disclosure.
[0020] Figure 3 This is a schematic flowchart illustrating the steps of determining a wind speed pitch angle model in a pitch control method for a wind turbine generator according to an exemplary embodiment of the present disclosure.
[0021] Figure 4 This is a schematic diagram illustrating a wind speed pitch angle model in a pitch control method for a wind turbine generator according to an exemplary embodiment of the present disclosure.
[0022] Figure 5This is a schematic flowchart illustrating the determination of a second relationship in a pitch control method for a wind turbine generator according to an exemplary embodiment of the present disclosure.
[0023] Figure 6 This is a schematic diagram illustrating a wind speed pitch angle correction model in a pitch control method for a wind turbine generator according to an exemplary embodiment of the present disclosure.
[0024] Figure 7 This is a schematic diagram illustrating pitch angle variation in a pitch control method for a wind turbine generator set according to an exemplary embodiment of the present disclosure.
[0025] Figure 8A , Figure 8B , Figure 8C and Figure 8D This is a schematic diagram illustrating the effect of employing a pitch control method for a wind turbine generator set 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] In view of the problems described above, this disclosure provides a pitch control method for a wind turbine generator set, a pitch control system for 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 for a wind turbine generator is provided. This pitch control method can be executed by a computer device with computing capabilities, for example, by a computer device in the pitch control system of the wind turbine generator. The computer device executing the pitch control method can be, for example, a terminal device or a server, wherein the terminal device can be such as a tablet computer, a laptop computer, a digital assistant, etc.; the server can be a standalone server, a server cluster, a cloud computing platform, or a virtualization center.
[0036] Here, computer equipment 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, so as to obtain the data required to perform the above method, such as measuring wind speed.
[0037] In embodiments according to this disclosure, the pitch control method for a wind turbine generator 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 rotor on the wind turbine side of the wind turbine generator set can be determined during the current control cycle.
[0039] In this step, the preset distance can be set according to actual needs. For example, the wind speed at the preset distance can be measured using wind measuring equipment such as lidar, millimeter-wave ranging radar, microwave radar, or acoustic radar, and the aforementioned wind speed data can be determined based on the measured wind speed. However, the embodiments of this disclosure are not limited to this, and the wind speed can also be obtained by other devices or methods, such as by estimating it using machine learning models or empirical models.
[0040] Specifically, taking the use of lidar to measure wind speed as an example, the lidar can be installed in the nacelle or on the wheel hub, such as... Figure 2 As shown, a lidar sensor may include four beams, such as LOS1, LOS2, LOS3 and LOS4, which can simultaneously measure multiple cross sections. The distances from different cross sections to the impeller can be different. For example, the distance from the first cross section P1 to the impeller can be d1, and the distance from the second cross section P2 to the impeller can be d2.
[0041] As the wind blows from the incoming side to the impeller, the wind speed may vary. Here, multiple wind speeds at a predetermined distance from the impeller can be acquired using lidar. For example, the wind speeds measured at the first cross-section P1 by beams LOS1, LOS2, LOS3, and LOS4 can be acquired. In this case, the predetermined distance D is d1. During the current control cycle, the wind speed data at the predetermined distance can be the average wind speed within the cross-section at that predetermined distance at the initial moment of the current control cycle, such as the average wind speed measured at the first cross-section P1 by beams LOS1, LOS2, LOS3, and LOS4.
[0042] In the above example, radar-based feedforward control technology can use radar hardware sensors to measure the wind speed in front of the impeller in advance, and control the pitch angle of the wind turbine to match the fluctuations in wind speed in real time. Experience shows that radar feedforward control is effective in controlling the rotational speed stability of the impeller and reducing the fatigue load on the entire machine. However, the embodiments of this disclosure are not limited to this. As mentioned above, other wind measuring devices or software models can also be used to determine the wind speed.
[0043] It should be noted that in the above example, there are no strict requirements on the number of wind measurement beams and the number of wind measurement distance sections of the lidar; for example, multiple preset distances can also be selected (e.g., Figure 2 The first distance d1 and the second distance d2 shown are used to collect wind speed data. Alternatively, the wind speed measured at the preset distance can be used as the wind speed data in this step. As long as the wind speed data can characterize the wind speed in front of the impeller (or the windward side), the pitch can be controlled in advance by measuring the wind in advance.
[0044] Return to reference Figure 1 In step S120, the estimated pitch angle for the current control cycle can be determined based on the wind speed data for the current control cycle.
[0045] In this step, the estimated pitch angle may refer to the pitch angle calculated based on wind speed data. In some examples, existing pitch control algorithms can be used to calculate the corresponding pitch angle as the estimated pitch angle based on the wind speed data obtained in step S110. An example of determining the estimated pitch angle will be given below by embodiments of this disclosure.
[0046] Specifically, the estimated pitch angle for the current control cycle can be determined as follows: based on the wind speed data for the current control cycle and the air density of the environment where the wind turbine is located, the estimated pitch angle for the current control cycle can be determined.
[0047] Even with the same wind speed, different wind densities can result in different loads on the generator set. Therefore, embodiments of this disclosure use both wind speed data and air density as inputs for calculating the pitch angle to achieve more precise pitch control and improve the load reduction effect of the generator set.
[0048] As an example, the relationship between wind speed data, air density, and pitch angle can be calculated through simulation. For instance, under the condition of meeting the power generation and load requirements of the unit, the optimal pitch angle corresponding to different wind speed data and different air densities can be simulated to obtain the relationship curve or relationship table of the three. 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 looking up 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 for 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 for the current control cycle.
[0050] The wind speed-pitch angle model can characterize the relationship between wind speed and pitch angle under current air density.
[0051] In one example, a machine learning model can be pre-trained based on historical wind speed and 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 wind turbine generators are complex nonlinear models, directly constructing a high-order model with high consistency is difficult. Obtaining relationship curves or tables through simulation requires a large number of data points, and training machine learning models also requires a high quantity and quality of samples. Therefore, these methods may generate a significant amount of preliminary work. To address this, embodiments of this disclosure also provide a method for determining the estimated pitch angle by constructing a low-order model and refining it, for subsequent pitch angle control.
[0053] In this example, the preset wind speed-pitch angle model is modified based on air density to obtain the modified 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 for the current control cycle. Here, the preset wind speed-pitch angle model represents the relationship between wind speed and pitch angle under a reference air density, while the modified wind speed-pitch angle model represents the relationship between wind speed and pitch angle under the current air density.
[0054] Specifically, a wind speed pitch angle model under a reference air density can be obtained. By modifying this model, a wind speed pitch angle model under the current air density can be obtained. 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 blade pitch angle under a reference air density can be determined.
[0056] Here, the reference air density can be, for example, the standard air density. Specifically, in the design process of wind turbine generator sets, the standard air density is used for the simulation calculation of the unit. This allows the wind speed-pitch-angle relationship to be obtained under the standard air density after the unit design is completed.
[0057] For example, the primary relationship between wind speed and blade pitch angle under standard air density can be obtained using simulation software such as DNV Bladed or NREL FAST. Figure 4 The curve shown. This first relationship can be a first wind speed pitch angle model under a reference air density, for example, it can be represented by θ=f(V), where θ represents the overall pitch angle of the aircraft under different wind speeds, and f() represents the relationship of the pitch angle obtained based on the wind speed under the reference air density.
[0058] Here, the optimal pitch angle can 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 can be a curve calculated based on the blade performance and overall losses of the wind turbine generator set, and the minimum pitch angle in this curve is the optimal pitch angle.
[0059] In step S320, a second relationship between the current air density and the reference air density can be determined based on the relationship between the active power of the wind turbine generator set, wind speed, and air density.
[0060] In this step, the second relation can be used to convert between the current air density and the reference air density in order to obtain the wind speed pitch angle model under the current air density based on the first relation.
[0061] As an example, the second relationship can be determined by the power calculation expression that characterizes the overall power generation performance. In this way, the second relationship can be obtained by the relationship between different air densities under the same power. Thus, by converting between the current air density and the reference air density, the wind speed pitch angle model under the current air density can be obtained quickly and easily.
[0062] For example, a second relation can be determined in the following way:
[0063] like Figure 5 In step S510, the first power relationship between the active power of the wind turbine generator set and the wind speed under a reference air density can be determined.
[0064] Specifically, the relationship between the active power of a wind turbine generator and the first power at wind speed under a reference air density can be expressed by the following equation (1):
[0065]
[0066] Where ρ0 represents the reference air density, such as the air density under standard conditions (e.g., 0°C, 1 standard atmosphere); R represents the radius of the wind turbine rotor; 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, the second power relationship between the active power of the wind turbine generator and the wind speed under the current air density can be determined.
[0068] In reality, air density and wind speed vary with factors such as geographical location, sea level, and topography. Therefore, the relationship between the active power of a wind turbine and the second power of 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 ′ This represents the active power of the wind turbine generator under the current air density. Here, the current air density can be the real-time air density during the control process, for example, obtained by real-time measurement through measuring equipment.
[0071] In step S530, the second relationship can be determined by keeping the active power constant and based on the first power relationship and the second power relationship.
[0072] In this step, for the first power relationship and the second power relationship mentioned above, since the air density is different, if it is desired to keep the active power constant, the second power relationship needs to be adjusted. In the second power relationship, the variable is wind speed. Therefore, the active power can be kept constant by weighting the wind speed in the second power relationship.
[0073] Specifically, we can assume that the weighted wind speed is V1. Under this weighted wind speed representation, the active power of the first power relationship and the second power relationship can remain unchanged, thus obtaining the following equation (3):
[0074]
[0075] Based on equation (3) above, the second relationship can be obtained as shown in equation (4) below:
[0076] ρ0V 3 =ρV1 3 (4)
[0077] Furthermore, the weighted wind speed can be obtained: Therefore, we can derive that, given an air density change from a reference air density to the current air density, the required change in wind speed to maintain a constant active power is:
[0078] In step S330, the wind speed pitch angle model can be determined based on the first relationship and the second relationship.
[0079] Since the performance curve of the whole machine (the relationship between wind speed and blade pitch angle) will shift under different air densities, the relationship curve under the current air density can be obtained by shifting it to the left or right based on the relationship curve under the reference air density.
[0080] As an example, the wind speed pitch angle model under a reference air density can be represented by the first relationship θ = f(V). Based on the second relationship in equation (4) above, the first relationship can be modified to obtain the wind speed pitch angle model under the current air density, which can be expressed as follows: For example, with the current air density ρ = 1.0 kg / m³ 3 For example, based on Figure 4 The models before and after the correction are obtained as follows: Figure 6 As shown.
[0081] By using the above method, starting from the power generation performance of the unit, and keeping the active power constant, the conversion relationship with air density can be obtained. Thus, based on the wind speed pitch angle model under the reference air density, the wind speed pitch angle model under any current air density can be corrected to obtain the wind speed pitch angle model.
[0082] It should be noted that although the process of determining the wind speed pitch angle model has been described above with reference to various formulas, the embodiments of this disclosure are not limited to this. The power generation performance of the unit can also be represented in other ways. For example, the above formula (1) can be represented in other forms, as long as the relationship between power generation performance parameters (such as the above active power), air density and wind speed can be established and the first relationship can be modified based on the relationship.
[0083] Return to reference Figure 1 In step S130, the estimated pitch angle of the current control cycle can be compared with the reference pitch angle of the previous control cycle, and the comparison result can be used as the reference pitch angle of the current control cycle.
[0084] In some cases, the pitch angle calculated based on wind speed can be directly used as the reference pitch angle output to control pitch. Here, in the embodiments of this disclosure, not only is it considered that pitch can be controlled in advance by measuring wind speed, but also that when wind speed is measured in advance, a large pitch angle can always be maintained before the wind reaches the impeller, thereby ensuring the effect of early pitch control on reducing unit load.
[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 phase, the estimated pitch angle of the initial control cycle can be used as the reference pitch angle of the initial control cycle.
[0087] As an example, suppose the duration of one control cycle of a wind turbine generator is Δt. Here, Δt can be set according to actual needs, for example, it can be 10ms or 20ms.
[0088] In the initial control period of any control phase (e.g., denoted as time 0), based on the wind speed data of the initial control period, for example through the modified model, the estimated pitch angle θ(0) for that control period (time 0) is obtained, and the final reference pitch angle (or pitch angle requirement value) θ is output. dmd (0)=θ(0).
[0089] In the next control cycle (e.g., denoted as 0+Δt), based on the wind speed data of that cycle, for example through the modified model, the estimated pitch angle θ(0+Δt) for that control cycle (0+Δt) is obtained.
[0090] Here, the estimated pitch angle θ(0+Δt) in response to the current control cycle is greater than or equal to the reference pitch angle θ of the previous control cycle. dmd (0), then the reference pitch angle θ for the current control cycle dmd (0+△t)=θ(0+△t); The estimated pitch angle θ(0+△t) in response to the current control cycle is less than the reference pitch angle θ of the previous control cycle. dmd (0), then the reference pitch angle θ for the current control cycle dmd (0+△t)=θ dmd (0).
[0091] In step S140, the blade pitch of the wind turbine can be controlled based on the reference pitch angle of the current control cycle.
[0092] By determining the reference pitch angle for the current control cycle, the blades of the wind turbine can be controlled to pitch, thereby adjusting the blade pitch angle to the required position in advance by taking advantage of advance wind measurements, thus achieving the goal of reducing load.
[0093] In the embodiments of this disclosure, the control process may include at least one control stage, and each control cycle in each control stage may be pitch control in the manner described above. Here, in the case of multiple control stages, in one example, the control stages may be switched according to a preset time interval.
[0094] In another example, each control phase can be determined based on the wind measurement lead time. Specifically, for any control phase, the pitch control method may further include: determining the number of cycles in the current control phase based on 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; and entering the next control phase in response to the number of control cycles in the current control phase reaching the required number of cycles.
[0095] As an example, statistical wind speed can be determined by: obtaining the wind speed at multiple times at a preset distance within a preset time period before the initial moment of the initial control cycle in the current control phase; and using the statistical values of the wind speed at multiple times as the statistical wind speed of the initial control cycle.
[0096] In this example, for the measured wind speed at a preset distance D, starting from the initial moment of the initial control cycle, the historical measured wind speeds at multiple moments preceding the initial moment can be statistically analyzed (e.g., averaged) according to a preset time period to obtain the aforementioned statistical wind speed.
[0097] As an example, the preset time period can be a preset sliding time window. Each time the statistical wind speed is calculated (e.g., when calculating the statistical wind speed at the initial moment of each control phase), the wind speed can be calculated backwards from the moment the statistical wind speed is to be calculated within this sliding time window, thus obtaining the statistical wind speed. This preset time period can be set according to actual needs, for example, it can be 100 seconds.
[0098] In the example above, by statistically analyzing the wind speed at multiple points in time, the current wind conditions and the travel time of the wind to the impeller can be determined more accurately. This allows for a more accurate determination of the number of cycles in the current control phase, enabling earlier pitch control.
[0099] Specifically, assuming the wind speed in front of the impeller satisfies the frozen rotor hypothesis, and the wind propagates forward according to the statistical wind speed obtained above, the advance time T for the measured wind speed to reach the impeller can be obtained, T = D / U, where D is the preset distance mentioned above, and U is the statistical wind speed. Therefore, it can be considered that for the statistical wind speed U at the preset distance D, calculated from the initial moment of any control stage, after time T, the wind at that preset distance D will reach the impeller surface. Thus, this time T can be used as the duration of a control stage.
[0100] As an example, steps S110 to S140 above can be executed N times. Thus, the control phase can include N control cycles. This number of cycles can represent the number of control cycles experienced by the unit within the time period during which the wind travels from a preset distance to the impeller. For example, this number of cycles N can be represented by the following formula (5):
[0101] N=T / Δt (5)
[0102] Within any control phase, steps S110 to S140 can be executed repeatedly until the number of control cycles in the control phase reaches the required number of cycles. Assuming the initial control cycle starts at time 0, and the current control cycle starts at time 0 + NΔt, the reference pitch angle θ for that control cycle can be updated. dmd (0+N*△t)=θ(0+N*△t), and this control period can be used as the initial control period for the next control stage.
[0103] In this way, the duration and number of cycles of each control stage can be reasonably set, so that as the wind moves to the impeller at the preset distance, it always maintains a pitch angle that can cope with the wind speed, thereby reducing the load on the unit when the wind speed comes.
[0104] Figure 7 The variation of the pitch angle during pitch control using the above control method is shown, as follows: Figure 7 As shown, in each control phase, the reference pitch angle can always be kept at a high level, thus enabling it to cope with the wind approaching the impeller.
[0105] The following will combine Figures 8A to 8D An example effect of employing a pitch control method according to an embodiment of the present disclosure is shown.
[0106] Taking a specific wind turbine generator as an example, after using the above method for control, as follows: Figure 8A As shown, for the ultimate load at the blade root, the bending moment load My along the y-axis of the blade root coordinate system decreases by 3.5%, the bending moment load Mz along the z-axis of the blade root coordinate system decreases by 3.9%, and the combined load Mxy along the x and y axes decreases by 4.2%; Figure 8B As shown, for the ultimate load at the tower base, the bending moment load My decreases by 4.7%, the bending moment load Mz decreases by 1.3%, and the combined load Mxy decreases by 4.3%. Figure 8C As shown, for blade root fatigue load, bending moment load My decreases by 1.0%, and bending moment load Mz decreases by 3.1%; Figure 8D As shown, for the fatigue load at the tower base, the bending moment load My decreases by 1.1%. Figure 8C and Figure 8DIn this context, m represents the m-value (also known as the Wohler exponent) in the SN curve representing the fatigue life characteristics of a material, indicating the relationship between stress level and fatigue life. The value of m varies for different materials; for example, the m-value for a blade could be 9 or 4.
[0107] The pitch control method for wind turbine generators disclosed herein can reduce the critical ultimate loads on multiple components such as blade root, tower top, and tower bottom by obtaining wind speed data in front of the rotor in advance and adjusting the pitch angle to the desired position corresponding to the incoming wind speed in advance, and can also achieve cost optimization of key components of the wind turbine generator.
[0108] According to a second aspect of the embodiments of the present disclosure, a pitch control system for a wind turbine generator set is provided. The pitch control system includes: a processor; and a memory for storing processor-executable instructions, wherein the processor-executable instructions, when executed by the processor, cause the processor to perform the pitch control method for the wind turbine generator set according to the embodiments of the present disclosure.
[0109] As an example, a pitch control system may include a wind measurement and acquisition module, a model building module, and a pitch angle control module. Here, the wind measurement and acquisition module determines the wind speed data at a preset distance from the rotor on the windward side of the wind turbine. The model building module determines an estimated pitch angle based on the wind speed data, for example, based on the overall performance curve of the wind turbine, and uses the comparison result as the reference pitch angle for the current control cycle by comparing the estimated pitch angle of the current control cycle with the reference pitch angle of the previous control cycle. The pitch angle control module executes the pitch angle control requirements based on the reference pitch angle.
[0110] The pitch control system may include computer equipment. Specifically, the pitch control method of the wind turbine generator described above can be executed by computer equipment.
[0111] As an example, a computer device can be a PC, tablet, personal digital assistant, smartphone, or other device capable of executing the aforementioned set of instructions. Here, a computer device is not necessarily a single electronic device, but can be any collection of devices or circuits capable of executing the aforementioned instructions (or instruction sets) individually or in combination. A computer device can also be part of an integrated control system or system manager, or can be configured to interface with a portable electronic device locally or remotely (e.g., via wireless transmission).
[0112] In computer 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 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 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.
[0114] 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.
[0115] In addition, computer equipment may include video displays (such as liquid crystal displays) and user interaction interfaces (such as keyboards, mice, touch input devices, etc.). All components of a computer device may be interconnected via buses and / or networks.
[0116] According to a third aspect of the embodiments of the present disclosure, a wind turbine generator set is provided, the wind turbine generator set including a pitch control system for the wind turbine generator set according to the embodiments of the present disclosure.
[0117] According to a fourth aspect of the embodiments of the present disclosure, a computer-readable storage medium is provided that, when instructions in the computer-readable storage medium are executed by a processor of an electronic device, enables the electronic device to perform a pitch control method for a wind turbine generator according to embodiments of the present disclosure.
[0118] Specifically, the pitch control method for a wind turbine generator set according to embodiments of the present 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 pitch control method for the wind turbine generator set according to exemplary embodiments 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 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 a computer program and any associated data, data files, and data structures in a non-transitory manner and to 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 across a networked computer system, such that the computer program 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.
[0119] According to a fifth aspect of the embodiments of the present disclosure, a computer program product is provided, comprising computer-executable instructions that, when executed by at least one processor, implement the pitch control method for a wind turbine generator according to the embodiments of the present disclosure.
[0120] 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.
[0121] 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.
[0122] 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.
[0123] 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 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 multiple control cycles, wherein, for any control cycle in any control stage, the pitch control method includes: Determine the wind speed data at a preset distance from the rotor on the wind turbine side of the wind turbine generator set during the current control cycle; Based on the wind speed data of the current control cycle, determine the estimated pitch angle for the current control cycle; Compare the estimated pitch angle of the current control cycle with the reference pitch angle of the previous control cycle, and use the comparison result as the reference pitch angle of the current control cycle. Based on the reference pitch angle of the current control cycle, the blades of the wind turbine generator are controlled to pitch. The step of determining the estimated pitch angle for the current control cycle based on wind speed data includes: Based on the current air density of the environment in which the wind turbine is located, the preset wind speed pitch angle model is corrected to obtain the corrected wind speed pitch angle model. The wind speed data for the current control cycle is input into the corrected wind speed-pitch angle model to obtain the estimated pitch angle for the current control cycle. The preset wind speed-pitch angle model represents the first relationship between wind speed and pitch angle under a reference air density, while the modified wind speed-pitch angle model represents the relationship between wind speed and pitch angle under the current air density. The modified wind speed pitch angle model is determined in the following manner: Determine the first relationship between wind speed and blade pitch angle at a reference air density; Based on the relationship between the active power of the wind turbine generator set, wind speed, and air density, a second relationship between the current air density and the reference air density is determined. Based on the first relationship and the second relationship, the modified wind speed pitch angle model is determined.
2. The pitch control method according to claim 1, characterized in that, For any control stage, the pitch control method further includes: The number of cycles in the current control phase is determined based on 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. When the number of control cycles in the current control phase reaches the specified number of cycles, the next control phase begins.
3. The pitch control method according to claim 2, characterized in that, The statistical wind speed is determined in the following manner: Get 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 phase; The statistical values of wind speed at the multiple times are taken as the statistical wind speed.
4. The pitch control method according to any one of claims 1 to 3, characterized in that, The step of 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, includes: The larger of the estimated pitch angle of the current control cycle and the reference pitch angle of the previous control cycle is used as the reference pitch angle of the current control cycle.
5. The pitch control method according to claim 4, characterized in that, The step of using the larger of the estimated pitch angle of the current control cycle and the reference pitch angle of the previous control cycle as the reference pitch angle of the current control cycle includes: 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.
6. The pitch control method according to claim 1, characterized in that, The second relationship is determined in the following manner: Determine the first power relationship between the active power of the wind turbine generator set and the wind speed under the reference air density; Determine a second power relationship between the active power of the wind turbine generator set and the wind speed under the current air density; By keeping the active power constant, the second relationship is determined based on the first power relationship and the second power relationship.
7. The pitch control method according to claim 1, characterized in that, In the initial control cycle of the current control phase, the estimated pitch angle of the initial control cycle is used as the reference pitch angle of the initial control cycle.
8. A pitch control system for a wind turbine generator set, characterized in that, The pitch control system includes: processor; Memory used to store the processor's executable instructions. Wherein, when the processor executes the executable instructions, it causes the processor to perform the pitch control method for a wind turbine generator according to any one of claims 1 to 7.
9. A wind turbine generator set, characterized in that, The wind turbine generator set includes the pitch control system for the wind turbine generator set according to claim 8.
10. 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 pitch control method for a wind turbine generator according to any one of claims 1 to 7.
11. 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 pitch control method for a wind turbine generator set according to any one of claims 1 to 7.