Pitch control method and system for wind turbine generator set and wind turbine generator set

Abstract

The present disclosure provides a pitch control method, system and wind turbine generator set, the pitch control method comprising: determining the d-axis load component and the q-axis load component of the current blade root load in the dq coordinate system; determining the d-axis pitch angle component corresponding to the d-axis load component and the q-axis pitch angle component corresponding to the q-axis load component; adjusting the q-axis pitch angle component based on the d-axis load component to obtain the q-axis control component of the independent pitch angle; adjusting the d-axis pitch angle component based on the q-axis load component to obtain the d-axis control component of the independent pitch angle; determining the independent pitch instruction of the blade based on the q-axis control component and the d-axis control component to control the blade pitch. The present disclosure solves the problem that the coupling between the d-axis and the q-axis in pitch control makes it difficult to accurately control the pitch, and can decouple the coupling between the q-axis and the d-axis, thereby improving the effect of reducing the adverse load of the unit by independent pitch control by adding decoupling control.

Description

Technical Field

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

[0002] Energy is the primary material foundation of social economy and human life, and the driving force of social development. However, as the reserves of non-renewable energy sources such as oil, coal, and natural gas, which are the mainstays of the world's energy, are dwindling, wind power generation technology has developed rapidly, and wind power generation, as a new energy source, has reached a mature scale.

[0003] In the control of wind turbines, independent pitch technology can significantly reduce the loads on wind turbine blades, hubs, yaw and other components. By directly or indirectly measuring the yaw load and the nacelle pitch load, the d-axis reference pitch angle and the q-axis reference pitch angle of each blade in the dq coordinate system are determined respectively, thereby controlling the pitch angle of the blade. Summary of the Invention

[0004] In a scheme for determining the d-axis reference pitch angle and the q-axis reference pitch angle of the blade based on the yaw direction load and the cabin pitch direction load, after the coordinate system transformation of the load is performed, two independent proportional integral differential controllers are used to output the d-axis reference pitch angle and the q-axis reference pitch angle respectively. In this process, the coupling amount between the d-axis and the q-axis is not discovered and taken into account, so that there is a load influence from the q-axis in the d-axis reference pitch angle, and there is a load influence from the d-axis in the q-axis reference pitch angle, making it difficult to achieve precise pitch control.

[0005] In view of the problem that the pitch control in the related art does not realize the coupling between the d-axis and the q-axis, resulting in difficulty in accurately controlling the pitch, the present disclosure provides a pitch control method and system for a wind turbine generator set, and a wind turbine generator set.

[0006] A first aspect of the present disclosure provides a pitch control method for a wind turbine generator set, the pitch control method comprising: determining a d-axis load component and a q-axis load component of a current blade root load of a blade of the wind turbine generator set in a dq coordinate system; respectively determining a d-axis pitch angle component corresponding to the d-axis load component and a q-axis pitch angle component corresponding to the q-axis load component; adjusting the q-axis pitch angle component based on the d-axis load component to obtain a q-axis control component of an independent pitch angle; adjusting the d-axis pitch angle component based on the q-axis load component to obtain a d-axis control component of an independent pitch angle; determining an independent pitch instruction for the blade based on the q-axis control component and the d-axis control component, and controlling the pitch of the blade.

[0007] Optionally, the q-axis control component is obtained in the following manner: based on the d-axis load component and the preset decoupling coefficient, a q-axis decoupling angle component is determined; the q-axis decoupling angle component is superimposed on the q-axis pitch angle component to obtain the q-axis control component, wherein the d-axis control component is obtained in the following manner: based on the q-axis load component and the decoupling coefficient, a d-axis decoupling angle component is determined; the d-axis decoupling angle component is superimposed on the d-axis pitch angle component to obtain the d-axis control component, wherein one of the q-axis decoupling angle component and the d-axis decoupling angle component is a positive value, and the other of the q-axis decoupling angle component and the d-axis decoupling angle component is a negative value.

[0008] Optionally, the decoupling coefficient is determined based on the impeller speed, the natural frequency of the blade during the pitch change process and the pitch sensitivity coefficient, or based on the generator speed, the transmission ratio between the impeller and the generator, the natural frequency of the blade during the pitch change process and the pitch sensitivity coefficient, and the pitch sensitivity coefficient characterizes the correspondence between the pitch angle of the blade and the blade root load.

[0009] Optionally, the decoupling coefficient is determined in the following manner: based on a first relationship between the actual pitch angle of the blade and the pitch angle control amount, and a second relationship between the actual pitch angle of the blade and the blade root load, a third relationship between the blade root load and the pitch angle control amount is determined; based on the third relationship, the decoupling coefficient is determined.

[0010] Optionally, the step of determining the decoupling coefficient based on the third relationship includes: determining the transformation matrix between the rotating coordinate system and the dq coordinate system; based on the transformation matrix, performing coordinate transformation on the blade root load and pitch angle in the third relationship to obtain a fourth relationship in the dq coordinate system; based on the q-axis and d-axis of the dq coordinate system, decomposing the fourth relationship to obtain the decoupling coefficient.

[0011] Optionally, the first relationship is determined based on the natural frequency of the blade during the pitch change process, and the second relationship is determined based on the damping ratio of the blade, the natural frequency of the blade during the pitch change process and the pitch sensitivity coefficient, and the pitch sensitivity coefficient characterizes the corresponding relationship between the pitch angle of the blade and the blade root load.

[0012] Optionally, the d-axis pitch angle component and the q-axis pitch angle component are determined in the following manner: the d-axis load component and the q-axis load component are synthesized to obtain a synthesized load; the synthesized load is compared with a control target threshold to obtain a comparison difference; based on the comparison difference, the d-axis pitch angle component and the q-axis pitch angle component are obtained through proportional-integral-differential control.

[0013] Optionally, the generator of the wind turbine generator set is a salient pole motor, the d-axis load component represents the load on the wind turbine generator set in the yaw direction, and the q-axis load component represents the load on the wind turbine generator set in the pitch direction of the nacelle.

[0014] A second aspect of the present disclosure provides a pitch control system for a wind turbine generator set, comprising: at least one processor; and at least one memory storing computer-executable instructions, wherein the computer-executable instructions, when executed by the at least one processor, prompt the at least one processor to execute the pitch control method for the wind turbine generator set according to an embodiment of the present disclosure.

[0015] A third aspect of the present disclosure provides a wind turbine generator set, comprising the pitch control system of the wind turbine generator set according to the embodiments of the present disclosure.

[0016] 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 an embodiment of the present disclosure.

[0017] 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 pitch control method for a wind turbine generator set according to an embodiment of the present disclosure.

[0018] According to the pitch control method, system and wind turbine generator set disclosed in the present invention, the d-axis pitch angle component corresponding to the d-axis load component and the q-axis pitch angle component corresponding to the q-axis load component can be determined respectively, and based on the d-axis load component, the q-axis pitch angle component is adjusted to obtain the q-axis control component of the independent pitch angle, and based on the q-axis load component, the d-axis pitch angle component is adjusted to obtain the d-axis control component of the independent pitch angle. In this way, when determining the q-axis and d-axis control components of the independent pitch angle, the coupling amount between the q-axis and the d-axis can be decoupled to avoid inaccurate pitch control due to the existence of the coupling amount, thereby improving the effect of reducing the adverse load of the unit by independent pitch by adding decoupling control. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1A and Figure 1B FIG. 1 is a schematic diagram illustrating independent pitch control results in pitch control of a wind turbine generator system according to the related art.

[0020] Figure 2 The figure is a flowchart illustrating a pitch control method of a wind turbine generator system according to an exemplary embodiment of the present disclosure.

[0021] Figure 3 is a schematic block diagram illustrating a pitch control method of a wind turbine generator system according to an exemplary embodiment of the present disclosure.

[0022] Figure 4 1 is a flow chart illustrating steps of determining a d-axis pitch angle component and a q-axis pitch angle component in a pitch control method of a wind turbine generator system according to an exemplary embodiment of the present disclosure.

[0023] Figure 5 1 is a flow chart illustrating steps of determining a decoupling coefficient in a pitch control method of a wind turbine generator system according to an exemplary embodiment of the present disclosure.

[0024] Figure 6 1 is a flow chart illustrating steps of determining a decoupling coefficient based on a third relationship in a pitch control method of a wind turbine generator set according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0025] The following detailed description is provided to help the reader gain a comprehensive understanding of the methods, devices and / or systems described herein. However, various changes, modifications and equivalents of the methods, devices and / or systems described herein will be clear after understanding the disclosure of the present application. For example, the order of operations described herein is merely 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 conciseness, descriptions of features known in the art may be omitted.

[0026] The features described herein can be implemented in different forms and should not be construed as limited to the examples described herein. Rather, the examples described herein are provided to illustrate only some of the many possible ways to implement the methods, devices, and / or systems described herein, which will become clear after understanding the disclosure of this application.

[0027] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more.

[0028] 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 used solely to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Thus, what is referred to as a first member, first component, first region, first layer, or first portion in the examples described herein may also be referred to as a second member, second component, second region, second layer, or second portion without departing from the teachings of the examples.

[0029] In the specification, when an element (such as a layer, region, or substrate) is described as being “on,” “connected to,” or “coupled to” another element, the element may be directly “on,” “connected to,” or “coupled to” the other 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.

[0030] 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 is intended to include the plural. The terms "comprise," "include," and "have" indicate the presence of the recited 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.

[0031] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure pertains after understanding the present disclosure. Unless expressly defined otherwise herein, terms (such as those defined in general dictionaries) 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.

[0032] Furthermore, in describing the examples, when it is deemed that a detailed description of well-known related structures or functions would cause ambiguous interpretation of the present disclosure, such detailed description will be omitted.

[0033] As mentioned above, the pitch control in the related art does not realize the coupling between the d-axis and the q-axis, which makes it difficult to accurately control the pitch. Figure 1A and Figure 1B Schematic diagram showing the independent pitch control results in the pitch control of a wind turbine generator set according to the related art. Figure 1A and Figure 1BAs shown in the figure, through the simulation of the pitch control process of the unit, when the torque in the yaw direction is applied to the tower using the independent pitch control (IPC), the acceleration in the y direction of the tower is weakened, while the acceleration in the x direction of the tower is enhanced. Figure 1A and Figure 1B In the figure, the dashed line represents the curve with IPC enabled, and the solid line represents the curve with IPC disabled. This shows that, in the control results, while enabling IPC reduces the tower's y-direction acceleration, it simultaneously increases the tower's x-direction acceleration. This demonstrates that in actual control, truly independent control of a single direction is difficult, resulting in poor control effectiveness.

[0034] In view of the above problems, 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 method for controlling the pitch of a wind turbine is provided. The method can be performed by an electronic device with computing capabilities, such as an electronic device in a pitch control system of the wind turbine. The electronic device performing the method can be, for example, a terminal device or a server, where the terminal device can be, for example, a tablet computer, a laptop computer, or a digital assistant; the server can be a standalone server, a server cluster, a cloud computing platform, or a virtualization center.

[0036] Here, the electronic device may be arranged at a wind turbine generator set or a wind farm, for example, and may be communicatively connected to a measuring device or a data center of the wind turbine generator set or wind farm, so as to obtain data required for executing the above method.

[0037] According to the pitch control method of the wind turbine generator set disclosed in the present invention, the coupling amount of the q-axis and the d-axis in the q-axis reference pitch angle and the d-axis reference pitch angle can be decoupled during the independent pitch control process, thereby avoiding the coupling between the q-axis and the d-axis causing inaccurate pitch control, thereby improving the effect of reducing the adverse load of the unit by independent pitch control.

[0038] The pitch control method of a wind turbine generator system according to the present disclosure may include the following steps:

[0039] like Figure 2 As shown, in step S210 , the d-axis load component and the q-axis load component of the current blade root load of the blade of the wind turbine generator set in the dq coordinate system may be determined.

[0040] In one example, the d-axis load component and the q-axis load component of the current blade root load in the dq coordinate system can be determined through coordinate transformation based on the current blade root load of the wind turbine blade and the rotor orientation data of the generator rotor.

[0041] Specifically, if Figure 3 As shown, taking a three-blade unit as an example, the blade root loads of the three blades in the horizontal direction x and vertical direction y, such as Mx1 and My1, Mx2 and My2, and Mx3 and My3, can be measured respectively. Based on the rotor azimuth angle of the generator rotor, the d-axis load component Md and the q-axis load component Mq of the blade root load in the dq coordinate system can be obtained through d / q-axis transformation.

[0042] Here, the d / q axis transformation is called the multi-blade coordinate (MBC) transformation in the impeller system, and its forward transformation and inverse transform The transformation matrix can be shown as follows (1) and (2):

[0043]

[0044] in, Indicates the rotor position data of the generator, such as the rotor azimuth angle.

[0045] In addition, the q-axis load component Mq can represent the load on the hub of the wind turbine in the yaw direction (for example, Myaw), and the d-axis load component Md can represent the load on the hub of the wind turbine in the pitch (or "nod") direction of the nacelle (for example, Mtilt).

[0046] In another example, the load Mtilt (e.g., the d-axis load component Md) and the load Myaw (e.g., the q-axis load component Mq) can be directly measured by sensors on the main shaft of the wind turbine generator set without measuring the blade root load and then synthesizing the q-axis load component Mq and the d-axis load component Md.

[0047] In step S220 , a d-axis pitch angle component corresponding to the d-axis load component and a q-axis pitch angle component corresponding to the q-axis load component may be determined respectively.

[0048] As an example, the d-axis pitch angle component and the q-axis pitch angle component can be determined according to an existing independent pitch control method. According to an embodiment of the present disclosure, the d-axis pitch angle component and the q-axis pitch angle component can be determined in the following manner:

[0049] like Figure 4As shown, in step S410, the d-axis load component and the q-axis load component may be synthesized to obtain a synthesized load.

[0050] Specifically, if Figure 3 As shown, the resultant load can be expressed as Here, Md represents the d-axis load component, and Mq represents the q-axis load component.

[0051] Furthermore, as an example, before obtaining the synthesized load, the d-axis load component and the q-axis load component may be filtered. For example, the d-axis load component and the q-axis load component may be input into filters to obtain filtered d-axis load component Md and q-axis load component Mq. Here, the filter may be, for example, a three-phase (3P) or six-phase (6P) filter. Thus, in step S410, the filtered d-axis load components may be synthesized to obtain the synthesized load.

[0052] In step S420 , the synthesized load may be compared with a control target threshold to obtain a comparison difference.

[0053] Here, the control target threshold can be set according to the actual situation. By determining the deviation between the q-axis load component Myaw and the d-axis load component Mtilt and the load control target, two independent proportional-integral-derivative (PID) controllers can be used to output the dq components of the blade angle control.

[0054] In step S430, the d-axis pitch angle component and the q-axis pitch angle component may be obtained based on the comparison difference through proportional-integral-differential control.

[0055] In this step, a PID controller or a PI controller can be used to determine the d-axis pitch angle component β for controlling the pitch angle of the blade based on the comparison difference. d and the q-axis pitch angle component β q .

[0056] Here, if the synthesized load is higher than the control target threshold, the difference between the transformed load and the threshold is used as the output of the PI controller. In order to prevent excessive movement of the variable pitch bearing, this control strategy generally uses the average blade angle and generator torque as the basis for table lookup, so that the IPC can only output when the unit load is large.

[0057] like Figure 3 As shown, in the related art, the d-axis pitch angle component β that is not decoupled can be d and the q-axis pitch angle component β qAfter the maximum pitch angle limit and d / q axis inverse transformation, the instruction of each blade is obtained, so that the independent pitch angle of each blade is superimposed on the pitch angle given value of the collective pitch control (CPC).

[0058] In addition, in unified pitch control, closed-loop control of the average pitch angle can be controlled according to the impeller speed, and the average pitch angle can be controlled by PI control and filters of the impeller tower and other frequencies. The present disclosure does not impose any special restrictions on the basic methods for determining unified pitch control and independent pitch control. As long as the d-axis and q-axis are involved in determining the reference pitch angles respectively in the independent pitch control, the decoupling method of the present disclosure can be adopted.

[0059] In step S230, the q-axis pitch angle component may be adjusted based on the d-axis load component to obtain the q-axis control component of the independent pitch angle.

[0060] In step S240, the d-axis pitch angle component may be adjusted based on the q-axis load component to obtain the d-axis control component of the independent pitch angle.

[0061] Specifically, the q-axis control component can be obtained by: determining the q-axis decoupling angle component based on the d-axis load component and the preset decoupling coefficient; and superimposing the q-axis decoupling angle component on the q-axis pitch angle component to obtain the q-axis control component.

[0062] For example, the d-axis load component and the preset decoupling coefficient can be multiplied, and the product can be used as the q-axis decoupling angle component, and the q-axis decoupling angle component can be superimposed on the q-axis pitch angle component to obtain the q-axis control component β′ of the independent pitch angle. q , as shown in the following formula (3):

[0063] β′ q =β q +s decouple M d (3)

[0064] Among them, s decouple represents the decoupling coefficient.

[0065] Similarly, the d-axis control component can be obtained by: determining the d-axis decoupling angle component based on the q-axis load component and the decoupling coefficient; and superimposing the d-axis decoupling angle component on the d-axis pitch angle component to obtain the d-axis control component.

[0066] Here, one of the q-axis decoupling angle component and the d-axis decoupling angle component is positive, and the other is negative. In other words, the q-axis decoupling angle component and the d-axis decoupling angle component have opposite signs.

[0067] For example, the q-axis load component and the decoupling coefficient can be multiplied, the inverse of the product can be used as the d-axis decoupling angle component, and the d-axis decoupling angle component can be superimposed on the d-axis pitch angle component, or it can be considered that the product of the q-axis load component and the decoupling coefficient is subtracted from the d-axis pitch angle component to obtain the d-axis control component β′ of the independent pitch angle. d , as shown in the following formula (4):

[0068] β′ d =β d -s decouple M q (4)

[0069] Through the above method, the coupling amount related to the d-axis load component can be removed from the q-axis pitch angle component, and the coupling amount related to the q-axis load component can be removed from the d-axis pitch angle component, so that the d-axis and q-axis control components of the independent pitch control are finally decoupled from the load of the other axis, thereby improving the pitch control effect.

[0070] Although the above equations (3) and (4) show example forms of determining the q-axis and d-axis control components, they are not limited thereto. For example, the signs of the q-axis decoupling angle component and the d-axis decoupling angle component may be interchanged.

[0071] In addition, the “pitch angle” in the IPC control process described herein may refer to the angular change of the pitch angle.

[0072] As an example, the decoupling coefficient can be determined based on the impeller speed, the natural frequency of the blade during the pitch change process and the pitch sensitivity coefficient, or based on the generator speed, the transmission ratio between the impeller and the generator, the natural frequency of the blade during the pitch change process and the pitch sensitivity coefficient. Here, the pitch sensitivity coefficient can characterize the correspondence between the pitch angle of the blade and the blade root load.

[0073] For example, the decoupling coefficient can be positively correlated with the impeller speed, negatively correlated with the blade's natural frequency during pitch change, and negatively correlated with the pitch sensitivity coefficient. The pitch sensitivity coefficient can be obtained based on data from the pitch angle to the blade root load in a simulation time series, which can be pre-determined based on the turbine's design parameters.

[0074] Taking the above formula (3) and formula (4) as an example, the decoupling coefficient s decouple It can be expressed by the following formula (5):

[0075]

[0076] Where Ω represents the impeller speed, which can be directly measured or determined based on the generator speed and the transmission ratio between the impeller and the generator. cIndicates the natural frequency of the blade, MTY sensitivity It represents the pitch sensitivity coefficient in the process of transforming the actual pitch angle of the blade into the blade root load.

[0077] The decoupling coefficient can characterize the portion of the coupling between the q-axis and the d-axis that is related to the unit state. Based on the decoupling coefficient and the q-axis / d-axis load, the coupling between the q-axis and the d-axis can be obtained to achieve decoupling control. Although the above formula (5) shows an example form of the decoupling coefficient, it is not limited to this. For example, it can also be expressed as Among them, k is an adjustable coefficient and can be adjusted according to actual needs.

[0078] As an example, the decoupling coefficient can be determined as follows:

[0079] like Figure 5 As shown, in step S510, the third relationship between the blade root load and the pitch angle control amount can be determined based on the first relationship between the actual pitch angle of the blade and the pitch angle control amount and the second relationship between the actual pitch angle of the blade and the blade root load.

[0080] In this step, the corresponding relationship between the blade root load and the pitch angle control amount can be converted by using the corresponding relationship between the actual blade pitch angle and the pitch angle control amount, and the corresponding relationship between the actual blade pitch angle and the blade root load. This relationship can be used to study the coupling problem in the load to pitch angle control process, so as to find the specific form of the decoupling amount, such as determining the decoupling coefficient. Here, the first relationship and the second relationship can be obtained by system identification or dynamic modeling.

[0081] As an example, when modeling the load from the pitch angle change of a single blade to the blade root as the research object, the first relationship can be determined based on the natural frequency of the blade during the pitch change process, for example, it can be expressed by the following formula (6):

[0082]

[0083] Among them, G pit (s) can represent the transfer function from the pitch angle control value (or called "pitch setting") to the actual pitch angle (or called "actual pitch angle"), and s represents the derivative in the time domain. Here, the transfer function G pit (s) can be determined by simulation timing based on the blade simulation model, ω c It can represent the natural frequency of the blade during the pitch change process from a given pitch angle to the actual pitch angle.

[0084] The second relationship can be determined based on the aerodynamic damping of the blade, the natural frequency in the dynamic process from the actual pitch angle of the blade to the blade root load, and the pitch sensitivity coefficient, for example, it can be expressed by the following formula (7):

[0085]

[0086] Among them, G bld (s) can represent the transfer function from the actual pitch angle of the blade to the blade root load; D represents the aerodynamic damping, which can be identified by simulation time series based on the blade simulation model, for example; ω r It is the natural frequency in the dynamic process from the actual pitch angle of the blade to the blade root load, which can be identified by simulation timing based on the blade simulation model, for example, and can be expressed by the square root of the blade stiffness and mass ratio in the parameter adjustment tool.

[0087] Here, the pitch sensitivity coefficient can be considered as the gain of the transfer function, which can characterize the magnitude of the unit conversion in the process of transforming the actual pitch angle of the blade to the blade root load. Specifically, the coefficient is obtained by converting from the unit of the pitch angle (such as degrees) to the unit of the load (such as Nm).

[0088] In addition, the above equations (6) and (7) can be obtained by simulation timing and fitting based on the blade simulation model, and the parameters (such as D, ω) can be determined according to the above equations (6) and (7). r 、MTY sensitivity ), for example, frequency ω r It can be obtained based on the constant term in the transfer function obtained during the simulation process, for example, the square root of the constant term; the pitch sensitivity coefficient MTY sensitivity It can be a unit conversion factor between the actual pitch angle and the blade root load, for example, it can be an integer power of 10; the aerodynamic damping D can be based on the frequency ω r And the first-order term in the transfer function obtained during the simulation is determined, such as the aerodynamic damping D and frequency ω r The product of can be used as 1 / 2 of the coefficient of the first-order term.

[0089] Based on the above equations (6) and (7), the third relationship G(s) can be converted into abc , as shown in the following formula (8):

[0090]

[0091] In step S520 , a decoupling coefficient may be determined based on the third relationship.

[0092] Here, since the third relationship represents the correspondence between the blade root load and the pitch angle control quantity, the expression of the blade root load in the process of determining the pitch angle control quantity can be analyzed based on the third relationship, and the coupling quantity between the d-axis and the q-axis can be found, so that the decoupling coefficient can be determined from the coupling quantity.

[0093] As an example, step S520 may include the following steps:

[0094] like Figure 6 As shown, in step S610, the transformation matrix between the rotation coordinate system and the dq coordinate system can be determined.

[0095] As an example, the transformation matrix between the rotating coordinate system and the dq coordinate system may be as shown in the above equations (1) and (2).

[0096] For the impeller system, the transformation matrix based on the MBC transformation is and the inverse transformation matrix The conversion relationship between the controlled objects before and after the MBC transformation can be obtained, for example, as shown in the following equations (9) to (13):

[0097]

[0098] Among them, β abc represents the pitch angles of the three blades in the rotating coordinate system (β a , β b and β c ), β dq represents the pitch angle (β in the dq coordinate system d and β q ), M abc represents the blade root load in the rotating coordinate system (M a 、M b and M c ), M dq represents the blade root load in the dq coordinate system (M d and M q ).

[0099] In step S620, coordinate transformation may be performed on the blade root load and the pitch angle in the third relationship based on the transformation matrix to obtain a fourth relationship in the dq coordinate system.

[0100] In this step, based on the third relationship between the blade root load and the pitch angle control amount determined above (for example, the transfer function shown in formula (8)), a transformation formula from the single blade pitch to the blade root load in the impeller coordinate system (abc coordinate system) can be obtained by mathematical expansion. For example, taking formula (8) as an example, it can be expanded into the form of the following formula (14):

[0101]

[0102] Among them, β pitc Indicates the pitch angle control value, M bld represents the blade root load.

[0103] For the above formula (14), the second-order component can be ignored. In addition, considering that the damping ratio D is one order of magnitude different from the frequency, the 2Dω in the first-order component can be ignored. c ω r For a single blade in the impeller coordinate system, the controlled object can be simplified to the following formula (15):

[0104]

[0105] Based on this simplified formula, the MBC transformation can be performed based on the above transformation matrix to obtain the following equations (16) and (17), where equation (17) represents the fourth relationship between the dq-axis pitch angle and the dq-axis blade root load in the dq coordinate system:

[0106]

[0107] in, It can be determined based on the impeller speed, for example, it can be expressed by the following formula (18):

[0108]

[0109] Where Ω represents the impeller speed.

[0110] Although it is described here that the second-order components of Equation (14) are simplified and some of the terms in the first-order components are simplified, it is not limited to this and the above simplifications may not be performed.

[0111] In step S630 , the fourth relationship may be decomposed based on the q-axis and the d-axis of the dq coordinate system to obtain a decoupling coefficient.

[0112] When the fourth relationship is determined, the fourth relationship can be decomposed based on the q-axis load component and the d-axis load component to separate the calculation components of the q-axis load component and the d-axis load component, thereby obtaining the coupling component. For example, for the above equation (17), the first-order component can be decomposed by mathematical methods to obtain the following equation (19):

[0113]

[0114] Based on formula (19), we can combine formula (18) above and substitute it into the relationship between the transformation matrix and the impeller speed to obtain the following formula (20):

[0115]

[0116] Based on the above formula (20), the d-axis reference pitch angle and the q-axis reference pitch angle of the independent pitch angle can be obtained respectively, as shown in formulas (21) and (22):

[0117]

[0118] Here, it can be seen that the q-axis reference pitch angle will produce a coupling component on the d-axis, such as The d-axis reference pitch angle will produce a coupling component on the q-axis, such as In the related art, the d-axis reference pitch angle β is directly obtained by PID control. d and q-axis reference pitch angle β q The presence of the aforementioned coupling components results in inaccurate control results. However, in the embodiments of the present disclosure, by analyzing the source and physical meaning of the coupling components, the specific form of the coupling components can be obtained, thereby determining the decoupling coefficient corresponding to the coupling components for decoupling control. The reference pitch angle here can also be referred to as the pitch angle setpoint or pitch angle control variable.

[0119] Specifically, taking the above equations (21) and (22) as examples, the coefficients of the coupling components can be determined from the expressions of the d-axis reference pitch angle and the q-axis reference pitch angle obtained by decomposition based on the fourth relationship, respectively, and the coefficients can be used as decoupling coefficients, for example, as shown in equation (5) above.

[0120] Here, during the IPC control process, the q-axis pitch angle component and the d-axis pitch angle component can be adjusted based on the decoupling coefficient. For example, the decoupling coefficient can be applied to the q-axis pitch angle component and the d-axis pitch angle component respectively to adjust the q-axis pitch angle component and the d-axis pitch angle component to obtain a feedforward decoupling component, which is then superimposed on the q-axis pitch angle component and the d-axis pitch angle component to obtain the final q-axis control component and the d-axis control component of the independent pitch angle. By introducing the feedforward decoupling component in the d-axis and the q-axis respectively, the coupling component can be eliminated, thereby optimizing the control effect of the IPC and reducing fatigue load.

[0121] For example, Figure 3 As shown, the feedforward coefficients FFd and FFq can be determined based on the decoupling coefficient to adjust the q-axis pitch angle component and the d-axis pitch angle component, wherein FFD = -FFq = s decouple .

[0122] Return to reference Figure 2 In step S250, the independent pitch command of the blade can be determined based on the q-axis control component and the d-axis control component, and the blade pitch can be controlled.

[0123] As mentioned above, the q-axis control component β′ can be obtained q and d-axis control component β′ q , generating independent pitch change commands for IPC.

[0124] For example, Figure 3 As shown, the decoupled q-axis control component β′ can be q and d-axis control component β′ q After processing such as maximum pitch angle limitation and d / q axis inverse transformation, the Figure 3 The independent pitch instructions of blades 1, blade 2 and blade 3 in the above diagram are obtained, so that the independent pitch angles of each blade can be superimposed on the pitch angle control amount of the CPC to obtain the final pitch speed instruction.

[0125] Here, the maximum pitch angle limitation can be performed based on the maximum limit factor, such as Figure 3 As shown, the maximum pitch angle can be determined based on the torque or the torque set point, and the minimum pitch angle can also be determined based on the pitch angle, so that the pitch angle is limited based on the maximum pitch angle and the minimum pitch angle.

[0126] It should be noted that although the above formulas illustrate the process of determining the decoupling coefficient in an illustrative manner, its specific form is not limited to that shown in the above formulas. Here, it is only for the convenience of understanding the concept of the present disclosure, and a three-blade unit is used as an example for explanation. The method of the present disclosure can also be applied to units with more or fewer blades, and the specific coordinate transformation method, polynomial solution or expansion can be achieved according to mathematical methods, as long as the coupling term can be decomposed for decoupling control.

[0127] According to the pitch control method of a wind turbine generator set in an embodiment of the present disclosure, full consideration is given to the coupling of the dq axes in the independent pitch control, and by analyzing the coupling components of the dq axes, decoupling control is added, and the q-axis pitch angle component and the d-axis pitch angle component are adjusted to obtain the decoupled q-axis control component and the d-axis control component of the independent pitch angle, thereby improving the effect of the independent pitch control in reducing the adverse load of the unit.

[0128] According to a second aspect of an embodiment of the present disclosure, a pitch control system of a wind turbine is provided. For example, the pitch control method of the above-mentioned wind turbine can be executed by an electronic device in the pitch control system, and the pitch control system includes: at least one processor; at least one memory storing computer-executable instructions, wherein the computer-executable instructions, when executed by at least one processor, prompt at least one processor to execute the pitch control method of the wind turbine according to the exemplary embodiment of the present disclosure.

[0129] As an example, the electronic device in the pitch control system can be a PC, tablet device, personal digital assistant, smartphone, or other device capable of executing the above-mentioned instruction set. Here, the electronic device does not necessarily have to be a single electronic device, but can also be any collection of devices or circuits that can execute the above-mentioned instructions (or instruction sets) individually or in combination. The electronic device can also be part of an integrated control system or system manager, or can be configured as a portable electronic device that is interconnected with a local or remote interface (e.g., via wireless transmission).

[0130] In electronic devices, a processor may include a central processing unit (CPU), a graphics processing unit (GPU), a programmable logic device, a dedicated processor system, a microcontroller, or a microprocessor. By way of example and not limitation, a processor may also include an analog processor, a digital processor, a microprocessor, a multi-core processor, a processor array, a network processor, and the like.

[0131] 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 over the network via the network interface device, wherein the network interface device can use any known transmission protocol.

[0132] The memory may be integrated with the processor, for example, by placing RAM or flash memory within an integrated circuit microprocessor or the like. Furthermore, the memory may comprise a separate device, such as an external disk drive, a storage array, or any other storage device usable by a database system. The memory and processor may be operatively coupled or may be in communication with each other, for example, via an I / O port, a network connection, or the like, such that the processor can access files stored in the memory.

[0133] In addition, the electronic 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 electronic device may be connected to each other via a bus and / or a network.

[0134] According to a third aspect of an embodiment of the present disclosure, a wind turbine generator set is provided. The wind turbine generator set may include the pitch control system of the wind turbine generator set according to the embodiment of the present disclosure.

[0135] 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 pitch control method of a wind turbine generator set according to an embodiment of the present disclosure.

[0136] 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 perform 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 ultra fast 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 configured to store the 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.

[0137] According to a fifth aspect of an embodiment of the present disclosure, a computer program product is provided, comprising computer-executable instructions, which, when executed by at least one processor, implement the pitch control method of a wind turbine generator set according to an embodiment of the present disclosure.

[0138] 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 pitch control method for a wind turbine generator set, characterized in that: The pitch control method comprises: Determine the d-axis load component and the q-axis load component of the current blade root load of the wind turbine blade in the dq coordinate system; respectively determining a d-axis pitch angle component corresponding to the d-axis load component and a q-axis pitch angle component corresponding to the q-axis load component; Adjusting the q-axis pitch angle component based on the d-axis load component to obtain a q-axis control component of an independent pitch angle; Based on the q-axis load component, adjusting the d-axis pitch angle component to obtain a d-axis control component of an independent pitch angle; determining independent pitch commands of the blades based on the q-axis control component and the d-axis control component, and controlling the pitch of the blades; The q-axis control component is obtained in the following manner: Determining a q-axis decoupling angle component based on the d-axis load component and a preset decoupling coefficient; The q-axis decoupling angle component is superimposed on the q-axis pitch angle component to obtain the q-axis control component, The d-axis control component is obtained by: determining a d-axis decoupling angle component based on the q-axis load component and the decoupling coefficient; The d-axis decoupling angle component is superimposed on the d-axis pitch angle component to obtain the d-axis control component, One of the q-axis decoupling angle component and the d-axis decoupling angle component is a positive value, and the other of the q-axis decoupling angle component and the d-axis decoupling angle component is a negative value.

2. The pitch control method according to claim 1, characterized in that: The decoupling coefficient is determined based on the impeller speed, the natural frequency of the blade during the pitch change process and the pitch sensitivity coefficient, or based on the generator speed, the transmission ratio between the impeller and the generator, the natural frequency of the blade during the pitch change process and the pitch sensitivity coefficient, and the pitch sensitivity coefficient characterizes the corresponding relationship between the pitch angle of the blade and the blade root load.

3. The pitch control method according to claim 1, characterized in that: The decoupling coefficient is determined by: determining a third relationship between the blade root load and the pitch angle control amount based on a first relationship between the actual pitch angle of the blade and the pitch angle control amount and a second relationship between the actual pitch angle of the blade and the blade root load; Based on the third relationship, the decoupling coefficient is determined.

4. The pitch control method according to claim 3, characterized in that: The step of determining the decoupling coefficient based on the third relationship includes: Determining a transformation matrix between a rotating coordinate system and the dq coordinate system; Based on the transformation matrix, coordinate transformation is performed on the blade root load and the pitch angle in the third relationship to obtain a fourth relationship in the dq coordinate system; The fourth relationship is decomposed based on the q-axis and the d-axis of the dq coordinate system to obtain the decoupling coefficient.

5. The pitch control method according to claim 3, characterized in that: The first relationship is determined based on the natural frequency of the blade during the pitch change process, and the second relationship is determined based on the damping ratio of the blade, the natural frequency of the blade during the pitch change process, and the pitch sensitivity coefficient, wherein the pitch sensitivity coefficient represents the corresponding relationship between the pitch angle of the blade and the blade root load.

6. The pitch control method according to claim 1, characterized in that: The d-axis pitch angle component and the q-axis pitch angle component are determined by: synthesizing the d-axis load component and the q-axis load component to obtain a synthesized load; Comparing the synthesized load with a control target threshold to obtain a comparison difference; Based on the comparison difference, the d-axis pitch angle component and the q-axis pitch angle component are obtained through proportional-integral-differential control.

7. The pitch control method according to claim 1, characterized in that: The d-axis load component represents the load on the wind turbine generator set in the yaw direction, and the q-axis load component represents the load on the wind turbine generator set in the pitch direction of the nacelle.

8. A pitch control system for a wind turbine generator set, characterized in that: include: at least one processor; at least one memory storing computer-executable instructions, Wherein, when the computer executable instructions are executed by the at least one processor, the at least one processor is prompted to execute the pitch control method for a wind turbine generator set 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 of 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 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 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, the pitch control method for a wind turbine generator set according to any one of claims 1 to 7 is implemented.

Images