Self-adaptive short-time frequency supporting method and system for doubly-fed wind turbine generator

Abstract

The invention discloses a self-adaptive short-time frequency support method and system for a doubly-fed wind turbine generator, and belongs to the technical field of new energy frequency control, and the method comprises the steps: controlling the wind turbine generator in a maximum power tracking mode when the wind turbine generator runs normally; monitoring the system frequency in real time, starting a frequency support stage when the frequency deviation exceeds a dead zone, and adaptively adjusting the output power according to the load disturbance degree determined by the system frequency change rate; and when the output power is reduced to the initial value of the frequency support stage, entering a rotor speed recovery stage, smoothly reducing the output power through an exponential function attenuation mechanism, and switching back to a normal mode when the output power intersects with the maximum tracking power. The power supporting strength is dynamically adjusted through the disturbance factors, the rotating speed recovery process is optimized, the lowest point of the frequency is effectively increased, secondary frequency drop is reduced, rotating speed recovery is accelerated, and the frequency stability of the power grid under different disturbances is remarkably enhanced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of new energy frequency control, and particularly relates to a doubly-fed wind turbine adaptive short-time frequency support method and system. BACKGROUND

[0002] With the dependence on traditional fossil fuels and the concern about global greenhouse gas emissions, wind power as a clean and renewable energy choice has gradually attracted people's attention. The increase in the installed capacity of wind turbines has led to a decrease in the proportion of traditional synchronous units in the power grid. This reduces the inertia of the power grid and seriously threatens the frequency stability of the power system. In addition, the randomness of wind energy leads to large fluctuations in the output of wind turbines. These problems limit the development of wind power and increase the frequency modulation pressure of synchronous generators. Therefore, wind turbines are urgently needed to take on the role of frequency support similar to synchronous generators in new power systems.

[0003] The short-time frequency support method realizes a fast dynamic response mechanism by introducing a power reference function design. Compared with the traditional rotor kinetic energy frequency modulation scheme, this method exhibits superior inertia support capability, which improves the minimum point of system frequency and enhances the anti-disturbance performance of the power grid. However, the effectiveness of short-time frequency support methods in improving frequency modulation performance is essentially limited by their power reference functions. In existing short-time frequency support methods, the active power trajectory of wind turbines during frequency modulation is fixed, which cannot adapt to different levels of load disturbance, resulting in insufficient frequency support capability. At the same time, the problem of secondary frequency drop and rotor speed recovery time of the system during speed recovery still needs to be further optimized.

[0004] In order to improve the frequency regulation capability of wind turbines under various load disturbances, it is necessary to study a short-time frequency control of wind turbines with frequency support and accelerated rotor speed. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a doubly-fed wind turbine adaptive short-time frequency support method and system to solve the technical problem of poor adaptability of fixed power curve in traditional short-time frequency support methods, in order to adapt to different levels of load disturbance.

[0006] The present application adopts the following technical solutions: A doubly-fed wind turbine adaptive short-time frequency support method, characterized in that it comprises the following steps: When the wind turbine is in normal operation, the wind turbine is controlled to be in a maximum power tracking mode, and outputs a maximum power tracking power matching the current operating condition ; Real-time monitoring of power system frequency, when the system frequency deviation is detected to exceed the frequency modulation dead zone, the frequency support stage is started, and the wind turbine output power is adaptively adjusted according to the load disturbance degree determined by the system frequency change rate; When the wind turbine output power drops to the power value at the start of the frequency support stage, the rotor speed recovery stage is entered, an exponential function attenuation mechanism is introduced, and the output power is smoothly reduced by an exponential function. When the wind turbine output power intersects with the maximum power tracking power , the wind turbine is controlled to switch back to the maximum power tracking mode, and the initial operating state is restored.

[0007] Preferably, the maximum power tracking power is:

[0008] wherein, p is the air density, R is the radius of the blade, ω r is the rotor speed of the wind turbine, C p is the wind energy conversion efficiency coefficient of the wind turbine, is the optimal tip speed ratio.

[0009] Preferably, the frequency support stage specifically comprises: calculating the system frequency change rate at the initial moment of disturbance, and constructing a disturbance factor based on the frequency change rate k d , the disturbance factor k d increases with the increase of the frequency change rate and decreases with the decrease of the frequency change rate; based on the disturbance factor k d , the MPPT power and the torque power limit , a first power reference value of the wind turbine is determined, and the wind turbine is controlled to output power according to the first power reference value to raise the lowest point of the frequency, and the first power reference value satisfies the power constraint condition; When the wind turbine output power reaches the maximum value, based on the initial rotor speed ω 0, the minimum rotor speed ω min and the current rotor speed, a second power reference value is determined, and the wind turbine is controlled to reduce the output power according to the second power reference value, until the second power reference value drops to the initial power P 0, the frequency support stage is ended.

[0010] Preferably, the disturbance factor k dAdjusting output power reference value of wind turbine , specifically:

[0011] wherein, is a coefficient of output power of the wind turbine in the MPPT mode, is a rotor speed of the wind turbine, is a power increment of the wind turbine at the initial moment of the perturbation.

[0012] Preferably, the perturbation factor k d is:

[0013] wherein, is a frequency change rate of the system at the initial moment of the perturbation, t is time.

[0014] Preferably, when the output power starts to decrease after reaching the maximum value, the power reference value is:

[0015] wherein, , are respectively the initial rotor speed and the minimum rotor speed, is the output power of the wind turbine in the AB section, is a rotor speed of the wind turbine, is the minimum output power of the wind turbine.

[0016] Preferably, the output power of the wind turbine in the AB section P 1 satisfies the following formula:

[0017]

[0018] wherein, is a torque power limit.

[0019] Preferably, the output power reference value of the exponential function decay mechanism is:

[0020] wherein, 、 are respectively the rotor speed at the C point and the corresponding moment; a is a negative constant coefficient, is the initial rotor speed, t is time.

[0021] Preferably, the wind turbine output power and the maximum power point tracking power are... The method for determining intersection is as follows: Real-time acquisition of the current rotor speed and corresponding output power of the wind turbine, and calculation of the current rotor speed at which the power output is calculated. When the two values ​​are equal, they are considered to intersect.

[0022] Secondly, embodiments of the present invention provide an adaptive short-time frequency support system for doubly-fed wind turbine generators, comprising: The tracking module controls the wind turbine to be in maximum power point tracking (MPPT) mode during normal operation, outputting the maximum PPT power that matches the current operating conditions. ; The adjustment module monitors the power system frequency in real time. When the system frequency deviation is detected to exceed the frequency regulation dead zone, the frequency support phase is activated, and the output power of the wind turbine is adaptively adjusted according to the load disturbance level determined by the system frequency change rate. The recovery module, when the wind turbine output power drops to the power value at the start of the frequency support phase, enters the rotor speed recovery phase, introducing an exponential function decay mechanism to smoothly reduce the output power through an exponential function. When the wind turbine output power reaches the maximum power point tracking power... When the two forces intersect, the wind turbine is controlled to switch back to maximum power point tracking mode and return to its initial operating state.

[0023] Thirdly, a computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-described adaptive short-time frequency support method for doubly-fed wind turbines.

[0024] Fourthly, embodiments of the present invention provide a computer-readable storage medium including a computer program, which, when executed by a processor, implements the steps of the above-described adaptive short-time frequency support method for doubly-fed wind turbine generators.

[0025] Fifthly, a chip includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-described adaptive short-time frequency support method for doubly-fed wind turbine generators.

[0026] In a sixth aspect, embodiments of the present invention provide an electronic device, including a computer program, which, when executed by the electronic device, implements the steps of the above-described adaptive short-time frequency support method for doubly-fed wind turbine generators.

[0027] Compared with the prior art, the present invention has at least the following beneficial effects: An adaptive short-time frequency support method for doubly-fed induction generator (DFIG) wind turbines is proposed. In the frequency support phase, a disturbance factor is designed based on the frequency change rate to characterize the magnitude of load disturbances. During frequency regulation, the initial output power of the wind turbine changes with the magnitude of the load disturbance, making more effective use of the turbine rotor kinetic energy. In the rotor speed recovery phase, the turbine power output curve adopts an exponential function form, utilizing its decay characteristics to gradually reduce the turbine output power, minimize secondary frequency drops, and accelerate rotor speed recovery. When the system experiences load disturbances of varying degrees, this method enhances the support for the lowest frequency point, reduces rotor speed recovery time, and improves system frequency stability.

[0028] Furthermore, by precisely defining the mathematical model for MPPT power, it is ensured that the wind turbine can continuously track and output the maximum possible power at the current wind speed during normal operation, providing a fundamental guarantee for the efficient utilization of wind energy. This precise modeling serves as the power benchmark for wind turbine participation in frequency regulation, ensuring that the power increment added during the subsequent frequency support phase is released in an orderly and controllable manner based on maximum energy capture. This avoids over-release or insufficient support problems caused by inaccurate power reference benchmarks, ensuring the accuracy and reliability of the control strategy.

[0029] Furthermore, the frequency support phase is further divided into an ascending segment and a descending segment, each employing different adaptive control laws. In the ascending segment, the power increment is dynamically adjusted using a disturbance factor to ensure strong support under large disturbances and avoid over-response under small disturbances. In the descending segment, the power is adjusted according to changes in rotational speed, achieving an orderly power withdrawal.

[0030] Furthermore, the additional power output of the wind turbine is proportional to the inertia support strength required by the system, achieving precise frequency support allocated on demand, greatly optimizing the utilization efficiency of rotor kinetic energy, and achieving the best frequency support effect with minimal kinetic energy loss.

[0031] Furthermore, this design avoids the risk of control instability caused by excessively large calculated values ​​under extreme disturbances, and naturally limits the range of influence of the disturbance factor to a safe and controllable range for the wind turbine. This design ensures the robustness and engineering practicality of the adaptive control.

[0032] Furthermore, when the rotational speed decreases due to the release of kinetic energy, this principle is used to reduce the power reference value, so that the power change is coordinated with the rotational speed change, achieving a smooth and natural decrease in power. This lays the foundation for a smooth transition to the rotational speed recovery stage and avoids the impact on the system frequency and the fan itself caused by sudden changes in power command.

[0033] Furthermore, this prevents the risk of excessively rapid rotor speed drops due to over-power generation, which could even jeopardize the stability of the wind turbine. These dual constraints jointly ensure the safe and stable operation of the wind turbine unit during frequency regulation.

[0034] Furthermore, it accelerates the rotor speed recovery speed, ensures frequency waveform stability, and resolves the contradiction between speed recovery and secondary frequency drop.

[0035] Furthermore, based on real-time feedback of equipment operating parameters, it has dynamic adaptability and is not affected by residual external disturbances, enabling the wind turbine to smoothly return to the optimal power generation state and ensuring frequency stability during the switching process.

[0036] It is understood that the beneficial effects of the second to sixth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here.

[0037] In summary, this invention constructs a disturbance factor based on the frequency change rate to achieve adaptive power adjustment and adapt to different load disturbances. The speed recovery incorporates an exponential decay mechanism, effectively reducing secondary frequency drops and accelerating speed recovery. Balancing power generation efficiency and equipment safety, it performs excellently under varying wind power penetration rates and wind speeds, significantly improving system frequency stability.

[0038] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0039] Figure 1 This is a block diagram of the adaptive short-time frequency support control for the doubly fed wind turbine of the present invention; Figure 2 The power curve of the adaptive short-time frequency support method for doubly fed wind turbines of the present invention; Figure 3 This refers to the magnitude change of the perturbation factor in this invention; Figure 4 This is a flowchart illustrating the adaptive short-time frequency support process for the doubly-fed wind turbine of the present invention. Figure 5 This is a model of an IEEE four-machine, two-area system including wind power. Figure 6 The simulation results are shown in the figure when the load disturbance is 0.08 pu; Figure 7 The simulation results are shown in the figure when the load disturbance is 0.12 pu; Figure 8 The simulation results are shown in the figure when the load disturbance is 0.15 pu; Figure 9 The simulation results are shown in the figure when the wind power penetration rate is 30%. Figure 10 The simulation results are shown in the figure when the wind power penetration rate is 40%. Figure 11 The simulation results are shown in the figure for high wind speed (12m / s); Figure 12A schematic diagram of a computer device provided in an embodiment of the present invention; Figure 13 This is a block diagram of a chip provided according to an embodiment of the present invention.

[0040] Among them, 60. Computer equipment; 61. Processor; 62. Memory; 63. Computer program; 600. Electronic device; 610. Processing unit; 620. Storage unit; 6201. Random access memory unit; 6202. Cache memory unit; 6203. Read-only memory unit; 6204. Program / utility; 6205. Program module; 630. Bus; 640. Display unit; 650. Input / output interface; 660. Network adapter; 700. External device. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0043] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0044] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0045] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0046] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0047] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0048] This invention provides an adaptive short-time frequency support method for doubly-fed induction generator (DFIG) wind turbines, incorporating the wind turbine output power trajectory with interference factors. The wind turbine can adaptively adjust its power reference value according to the load disturbance level to improve support for the lowest frequency point. Simultaneously, by smoothing the wind turbine power during the rotor speed recovery phase, secondary frequency drops are reduced and rotor speed recovery is accelerated. This invention improves the frequency stability of the DFIG system under different load disturbances.

[0049] Please see Figure 1 The adaptive short-time frequency support control method for doubly-fed induction generator (DFIG) wind turbines of this invention includes an MPPT (Maximum Power Point Tracking) module, a frequency support module, and a rotor speed recovery module. The frequency support module primarily provides active power support to the system during disturbances, raising the minimum frequency point. The rotor speed recovery module mainly accelerates rotor speed recovery and reduces secondary frequency drops.

[0050] Please see Figure 2 The present invention discloses an adaptive short-time frequency support method for doubly-fed wind turbine generators, comprising the following steps: S1, Normal operating status of the wind turbine unit; Under normal operating conditions, the doubly-fed induction generator (DFIG) wind turbine operates in MPPT mode, and the system frequency remains stable. At this time, the output power of the wind turbine is: (1) in, P MPPT This refers to the output power of the wind turbine. p It is air density. R Represents the radius of the blade. ω r Indicates the rotor speed of the wind turbine. C p Defined as the wind energy conversion efficiency coefficient of a wind turbine, it is the pitch angle. β Speed ​​ratio with leaf tip λ The function.

[0051] S2, the implementation process of the frequency support phase; During frequency events in the power system, wind turbines regulate frequency through rotational kinetic energy. This is achieved by adding additional power Δ in MPPT mode. P To increase the output power of the wind turbine, as shown in the following formula: (2) in, P ref This is a reference value for the output power of the wind turbine.

[0052] Δ in existing methods P The fixed value makes the wind turbine's output power unadaptable, affecting its frequency regulation performance. Therefore, during the frequency support phase, the wind turbine needs to adjust its power output according to the load level to optimize its frequency support capability. The magnitude of the frequency change rate at the initial moment of the disturbance can characterize the degree of load disturbance. A disturbance factor based on the frequency change rate was designed. k d Specifically, it is expressed as: (3) in, RoCoF | t=t0+ Let be the rate of change of the system's frequency at the initial moment of the disturbance. t For time.

[0053] Figure 3 The variation law of the disturbance factor is shown. When the disturbance is large, the rate of change of the measured frequency increases. According to equation (3). k d The value will increase until it reaches its maximum. Similarly, when the perturbation is minimal, k d The value decreases accordingly. This is achieved by adding a disturbance factor to the wind turbine output power curve. kd This is to achieve adaptive frequency regulation. The power output of the wind turbine at this stage is referenced to the following formula, corresponding to... Figure 2 The AB segment of the curve.

[0054] (4) in, P Tlim0 This is the torque power limit.

[0055] at the same time, P 1. The following condition must be met:

[0056] (5) When the wind turbine output power reaches its maximum value ( Figure 2 At point B in the diagram, the power will begin to gradually decrease. At this point, the power reference value is set as follows: (6) in, ω 0、 ω min These are the initial rotor speed and the minimum rotor speed, respectively.

[0057] When the wind turbine reaches point C, the frequency support phase ends. At this point, it is necessary to switch the wind turbine's power curve to enter the speed recovery phase. Traditional short-time frequency support strategies begin speed recovery at the moment of speed convergence. However, at this point, the grid frequency has already been in a quasi-steady state for some time, and there is no need for the wind turbine to continue injecting active power into the grid.

[0058] In this invention, when the active power reference value of the wind turbine in section BC drops to the initial power... P At 0, the speed recovery control will be activated. The active power reference at point C at this time is as follows: (7) S3, the implementation process of the speed recovery phase.

[0059] During the rotor speed recovery phase, the wind turbine absorbs energy to increase rotor speed by reducing its output power; however, a sudden power drop can cause a significant drop in the secondary frequency of the system. Therefore, appropriate control functions are needed to smooth the power drop of the wind turbine, reduce SFD (secondary frequency drop), and accelerate speed recovery.

[0060] Therefore, an exponential function decay mechanism is introduced. By adjusting the power reference value through an exponential function, the wind turbine output power exhibits a rapid initial decrease followed by a slower decrease, thus achieving a gradual power reduction. The active power output of the wind turbine during this stage is shown below: (8) in, ω C 、t C These represent the rotational speed at point C and the corresponding time. a It is a constant, taken as -0.8.

[0061] When the power curve of the wind turbine intersects the MPPT curve at point D, P ref ( ω D )= P MPPT ( ω D At this point, the wind turbine switches to MPPT control mode. Finally, the wind turbine returns to point A along the maximum power point tracking curve, resuming its initial operating state. The power expression for segment DA is as follows: (9) In another embodiment of the present invention, an adaptive short-time frequency support system for doubly-fed wind turbines is provided. This system can be used to implement the above-mentioned adaptive short-time frequency support method for doubly-fed wind turbines. Specifically, the adaptive short-time frequency support system for doubly-fed wind turbines includes a tracking module, an adjustment module, and a recovery module.

[0062] The tracking module, during normal operation of the wind turbine, controls the wind turbine to be in maximum power point tracking (MPPT) mode, outputting the maximum MPPT power that matches the current operating conditions. ; The adjustment module monitors the power system frequency in real time. When the system frequency deviation is detected to exceed the frequency regulation dead zone, the frequency support phase is activated, and the output power of the wind turbine is adaptively adjusted according to the load disturbance level determined by the system frequency change rate. The recovery module, when the wind turbine output power drops to the power value at the start of the frequency support phase, enters the rotor speed recovery phase, introducing an exponential function decay mechanism to smoothly reduce the output power through an exponential function. When the wind turbine output power reaches the maximum power point tracking power... When the two forces intersect, the wind turbine is controlled to switch back to maximum power point tracking mode and return to its initial operating state.

[0063] This invention provides a terminal device comprising a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing and control core of the terminal, suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions to achieve a corresponding method flow or corresponding function. The processor described in this embodiment can be used in the operation of a doubly-fed wind turbine adaptive short-time frequency support method, including: When the wind turbine is operating normally, it is controlled to be in maximum power point tracking (MPPT) mode, outputting the maximum PPT power that matches the current operating conditions. The system monitors the power system frequency in real time. When a frequency deviation exceeding the frequency regulation dead zone is detected, a frequency support phase is initiated. The wind turbine output power is adaptively adjusted based on the load disturbance level determined by the system frequency change rate. When the wind turbine output power drops to the power value at the start of the frequency support phase, a rotor speed recovery phase is entered. An exponential function decay mechanism is introduced to smoothly reduce the output power through an exponential function. When the wind turbine output power reaches the maximum power point tracking power... When the two forces intersect, the wind turbine is controlled to switch back to maximum power point tracking mode and return to its initial operating state.

[0064] Please see Figure 12 The terminal device is a computer device. In this embodiment, the computer device 60 includes a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When executed by the processor 61, the computer program 63 implements the method for estimating the concentration of radioactive iodine species in the containment after an accident, as described in this embodiment. To avoid repetition, this will not be elaborated here. Alternatively, when executed by the processor 61, the computer program 63 implements the functions of each model / unit in the adaptive short-time frequency support system of the doubly-fed wind turbine, as described in this embodiment. To avoid repetition, this will not be elaborated here.

[0065] Computer device 60 can be a desktop computer, laptop, handheld computer, cloud server, or other computing device. Computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art will understand that... Figure 12 This is merely an example of computer device 60 and does not constitute a limitation on computer device 60. It may include more or fewer components than shown, or combine certain components, or different components. For example, computer device may also include input / output devices, network access devices, buses, etc.

[0066] The processor 61 may be a Central Processing Unit (CPU), or other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0067] The memory 62 can be an internal storage unit of the computer device 60, such as a hard disk or RAM of the computer device 60. The memory 62 can also be an external storage device of the computer device 60, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., provided on the computer device 60.

[0068] Furthermore, the memory 62 may include both internal storage units of the computer device 60 and external storage devices. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 can also be used to temporarily store data that has been output or will be output.

[0069] Please see Figure 13The terminal device is an electronic device 600, which is manifested in the form of a general-purpose computing device. The components of the electronic device may include, but are not limited to: at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different platform components (including storage unit 620 and processing unit 610), a display unit 640, etc.

[0070] The storage unit stores program code, which can be executed by the processing unit 610 to perform the steps described in the method section of this specification according to various exemplary embodiments of the present invention. For example, the processing unit 610 can perform actions such as... Figure 1 The steps are shown in the figure.

[0071] Storage unit 620 may include a readable medium in the form of a volatile storage unit, such as random access memory (RAM) 6201 and / or cache memory 6202, and may further include a read-only memory (ROM) 6203.

[0072] Storage unit 620 may also include a program / utility 6204 having a set (at least one) program module 6205, such program module 6205 including but not limited to: operating system, one or more application programs, other program modules and program data, each or some combination of these examples may include an implementation of a network environment.

[0073] Bus 630 can represent one or more of several types of bus structures, including a memory cell bus or memory cell controller, a peripheral bus, a graphics acceleration port, a processing unit, or a local bus using any of the multiple bus structures.

[0074] Electronic device 600 can also communicate with one or more external devices 700 (e.g., keyboard, pointing device, Bluetooth device, etc.), and with one or more devices that enable a user to interact with electronic device 600, and / or with any device that enables electronic device 600 to communicate with one or more other computing devices (e.g., router, modem). This communication can be performed via input / output interface 650. Furthermore, electronic device 600 can also communicate with one or more networks (e.g., local area network, wide area network, and / or public network, such as the Internet) via network adapter 660. Network adapter 660 can communicate with other modules of electronic device 600 via bus 630. It should be understood that, although not shown in the figures, other hardware and / or software modules can be used in conjunction with electronic device 600, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms.

[0075] Example 4 This invention also provides a storage medium, specifically a computer-readable storage medium, which is a memory device in a terminal device for storing programs and data. It is understood that the computer-readable storage medium here can include both built-in storage media in the terminal device and extended storage media supported by the terminal device; it can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, the storage space also stores one or more instructions suitable for loading and execution by a processor, which can be one or more computer programs (including program code). More specific examples of the computer-readable storage medium include: an electrical connection with one or more wires, a portable disk, a hard disk, random access memory, read-only memory, erasable programmable read-only memory, optical fiber, portable compact disk read-only memory, optical storage device, magnetic storage device, or any suitable combination thereof.

[0076] Computer-readable storage media also include data signals propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable storage medium can also be any readable medium other than a readable storage medium that can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the readable storage medium can be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, radio frequency, etc., or any suitable combination thereof.

[0077] Program code for performing the operations of this invention can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0078] One or more instructions stored in a computer-readable storage medium can be loaded and executed by a processor to implement the corresponding steps of the adaptive short-time frequency support method for doubly-fed wind turbines in the above embodiments; one or more instructions in the computer-readable storage medium are loaded and executed by the processor to perform the following steps: When the wind turbine is operating normally, it is controlled to be in maximum power point tracking (MPPT) mode, outputting the maximum PPT power that matches the current operating conditions. The system monitors the power system frequency in real time. When a frequency deviation exceeding the frequency regulation dead zone is detected, a frequency support phase is initiated. The wind turbine output power is adaptively adjusted based on the load disturbance level determined by the system frequency change rate. When the wind turbine output power drops to the power value at the start of the frequency support phase, a rotor speed recovery phase is entered. An exponential function decay mechanism is introduced to smoothly reduce the output power through an exponential function. When the wind turbine output power reaches the maximum power point tracking power... When the two forces intersect, the wind turbine is controlled to switch back to maximum power point tracking mode and return to its initial operating state.

[0079] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0080] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0081] Please see Figure 4 A technical flowchart of the present invention is provided. Combined with... Figure 1 and Figure 4 The specific implementation of this invention will be described. When a disturbance occurs in the system, the frequency fluctuates. When the system frequency deviation exceeds the frequency modulation dead zone, switch S1 changes from 0 to 1. The system then enters the frequency support stage. Figure 2In the AC segment of the system, the corresponding disturbance factor is calculated based on the magnitude of the load disturbance. The wind turbine adaptively adjusts its output power according to the magnitude of the disturbance factor to better support the system frequency. As the rotor speed decreases, the turbine power gradually decreases. When the power drops to the initial power, switch S1 changes from 1 to 2, entering the rotor speed recovery stage. Figure 2 (C / D segment in the diagram). During this stage, an exponential function is used to smooth the fan power, thereby accelerating speed recovery and reducing secondary frequency drops. When the fan output power equals the power in maximum power point tracking (MPPT) mode, switch S1 changes from 2 to 0, and the fan returns to MPPT mode.

[0082] Furthermore, simulations were conducted under different load disturbances, wind power penetration rates, and wind speeds, comparing the proposed method with two comparative methods (Method #1 and #2). Compared to the two comparative methods, the proposed method demonstrates superior frequency regulation performance. According to the simulation data, the proposed method can reduce the speed recovery time by up to 18.84 seconds and raise the frequency minimum by 0.3 Hz. This demonstrates the effectiveness and superiority of the proposed method in enhancing the frequency minimum and accelerating speed recovery. Table 1 shows the simulation results.

[0083] Table 1

[0084] Example 5 like Figure 5 As shown, this method uses an IEEE four-unit, two-zone system including a wind farm as the test system. The total capacity of the thermal power units is 300MW, and the primary response descent rate is set to 5%. The load consists of two parts: static load and dynamic load, represented by Load1 and Load2, respectively. Changes in Load2 represent disturbances in the system. The grid's baseline capacity is 300MW. The proposed method was simulated, and simulations were performed with two comparative methods (methods #1 and #2) under different load disturbances, wind power penetration rates, and wind speeds, as detailed below: (1) The wind power penetration rate was set to 20% and the wind speed was 10m / s. Simulations were performed under load disturbances of 0.08pu, 0.12pu and 0.15pu, corresponding to Cases 1-3 respectively.

[0085] Figure 6The simulation results are shown in the figure at time t=10s with a load disturbance of 0.08 pu. The proposed method has the highest output power and the best frequency support capability. When using MPPT, method #1, and method #2, the lowest frequency points of the system are 49.43Hz, 49.55Hz, and 49.60Hz, respectively. These are all lower than the 49.61Hz of the proposed method. During the rotor speed recovery phase, the proposed method slowly reduces the output power of the wind turbine in the form of an exponential function, effectively mitigating the secondary frequency drop. Figure 6 The recovery time of the proposed method was found to be 57.34 s, which is 9.49 s faster than method #1 and 3.01 s faster than method #2.

[0086] Figure 7 The simulation results are shown at time t=10s with a load disturbance of 0.12 pu. The proposed method adjusts the wind turbine output power based on the frequency change rate. As the load disturbance increases, the frequency change rate increases. When three different methods are used, the lowest frequency points are 49.27Hz, 49.33Hz, and 49.41Hz. The proposed method improves the lowest frequency points by 0.14Hz and 0.08Hz, respectively. Figure 7 As shown, the rotational speed recovery curve is displayed. The recovery time under the proposed method is 59.87 seconds. Compared with 68.43 seconds for method #1 and 61.76 seconds for method #2, the recovery time is reduced by 12.5% ​​and 2.8%, respectively.

[0087] Figure 8 The simulation results are shown in the figure at time t=10s and load disturbance of 0.15 pu. The proposed method adjusts the frequency by setting an adaptive output power curve for the wind turbine. The increase in load disturbance makes the frequency change rate in Case 3 greater than that in Case 1 and Case 2. Figure 8 The frequency variation process of the system is shown. The lowest frequency of the proposed method is 49.26 Hz. Compared with the two comparative methods, the lowest frequency increased by 0.19 Hz and 0.14 Hz, respectively. Compared with methods #1 and #2, which produced secondary frequency drops of 49.52 Hz and 49.50 Hz, respectively, the proposed method significantly reduced the secondary frequency drop. Figure 8 The simulation also shows the rotor speed recovery process using different control methods. The proposed method optimizes rotor speed recovery using an exponential curve, thus shortening the rotor speed recovery time. Simulation results show that the recovery time using the proposed method is 59.84 seconds, which is faster than Method 2 (61.60 seconds) and Method 1 (67.63 seconds).

[0088] (2) The wind speed is 10 m / s and the load disturbance is 0.08 pu. Simulations were conducted at wind power penetration rates of 30% and 40%, respectively, corresponding to Cases 4-5.

[0089] Figure 9 Simulation results are shown at time t=10s and wind power penetration rate of 30%. Using MPPT, methods #1 and #2, the lowest system frequencies are 49.37Hz, 49.52Hz, and 49.56Hz, respectively, all lower than the 49.57Hz of the proposed method. The speed recovery function in the proposed method effectively compensates for the power drop of the wind turbine and mitigates the secondary frequency drop. In addition to accelerating speed recovery, faster initiation of speed recovery also prevents excessive release of rotor kinetic energy. The speed recovery time of the proposed method is 56.20s, which is 12.15s and 7.89s shorter than methods #1 and #2, respectively.

[0090] Figure 10 Simulation results are shown at time t=10s and a wind power penetration rate of 40%. Compared with the two comparative methods, the proposed method can increase the minimum frequency point by 0.05Hz and 0.02Hz, respectively. The proposed method regulates the maximum drop in rotor speed to within 0.05pu, thereby ensuring the safe operation of the wind turbine. The recovery time using the proposed method is 48.71 seconds, which is 1.5 seconds and 3.98 seconds faster than the comparative methods, respectively. The proposed method helps the wind turbine quickly recover to its initial state after frequency regulation operations. The analysis of Case 4 and Case 5 shows that the proposed method maintains effective frequency management under different wind power penetration rates, increases the minimum frequency point, and reduces the time required for rotor speed recovery.

[0091] (3) A simulation was conducted at a wind speed of 12 m / s, corresponding to Case 6.

[0092] Figure 11 The simulation results are shown at time t=10s and wind speed 12m / s. When using the proposed method, the lowest frequency is 49.61Hz. Compared with method #2, the lowest frequency is improved by 0.02Hz. Although method #1 has the strongest frequency support capability, its frequency waveform changes more, with a secondary frequency lowest point of 49.63Hz. In contrast, this method has a good system frequency waveform and a smaller SFD; the velocity recovery time of the proposed method is 47.98s, which is less than 66.82s for method #1 and 49.72s for method #2.

[0093] In summary, this invention provides an adaptive short-time frequency support method and system for doubly-fed induction generator (DFIG) wind turbines. By introducing a disturbance factor based on the frequency change rate, the frequency support power of the wind turbine can be matched in real time to the severity of grid disturbances, completely solving the key problem that traditional methods, due to their fixed power curves, cannot adapt to different disturbance scenarios. Dynamic power increment allocation and orderly power drop trajectory can more effectively raise the minimum system frequency, enhancing the frequency stability of the grid. During the speed recovery phase, the exponential function is used to smooth the power drop, significantly mitigating the secondary frequency drop caused by sudden power decreases. The optimized power drop law enables the wind turbine to recover kinetic energy and restore speed more quickly, shortening the duration of frequency regulation service and allowing it to prepare for the next disturbance more quickly. The entire control process incorporates power and torque constraints, ensuring the safe and stable operation of the wind turbine during frequency regulation, preventing overload and instability risks, and effectively improving the frequency response quality, grid adaptability, and safety of the DFIG wind turbine.

[0094] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0095] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0096] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0097] In the embodiments provided by this invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0098] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0099] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0100] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random-access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electrical carrier signals and telecommunication signals.

[0101] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus, and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0102] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0103] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0104] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for adaptive short-time frequency support of a doubly-fed wind turbine generator, characterized in that, Includes the following steps: S1. When the wind turbine is running normally, control the wind turbine to be in maximum power point tracking mode, and output the maximum power point tracking power that matches the current operating conditions. ; S2. Real-time monitoring of the power system frequency. When the system frequency deviation is detected to exceed the frequency regulation dead zone, the frequency support phase is initiated, and the output power of the wind turbine is adaptively adjusted according to the load disturbance level determined by the system frequency change rate. S3. When the wind turbine output power drops to the power value at the start of the frequency support phase, the rotor speed recovery phase begins. An exponential function decay mechanism is introduced to smoothly reduce the output power through an exponential function. When the wind turbine output power reaches the maximum power point tracking power... When the two forces intersect, the wind turbine is controlled to switch back to maximum power point tracking mode and return to its initial operating state.

2. The adaptive short-time frequency support method for doubly-fed wind turbine generators according to claim 1, characterized in that, Maximum power tracking power for: in, ρ air density, R Let be the radius of the blade. ω r This refers to the rotor speed of the wind turbine. C p The wind energy conversion efficiency coefficient of the wind turbine unit. The optimal tip speed ratio.

3. The adaptive short-time frequency support method for doubly-fed wind turbine generators according to claim 1, characterized in that, The frequency support phase specifically includes: Calculate the system frequency change rate at the initial moment of the disturbance, and construct the disturbance factor based on the frequency change rate. k d The disturbance factor k d It increases with increasing rate of change of frequency and decreases with decreasing rate of change of frequency; Based on the disturbance factor k d MPPT power and torque power limit Determine the first power reference value of the wind turbine, control the wind turbine to output power according to the first power reference value to increase the lowest frequency point, and the first power reference value meets the power constraint conditions. Once the wind turbine output power reaches its maximum value, based on the initial rotor speed... ω 0. Minimum rotor speed ω min Based on the current rotor speed, determine the second power reference value, and control the wind turbine to reduce its output power according to the second power reference value until the second power reference value drops to the initial power. P At 0, the frequency support phase ends.

4. The adaptive short-time frequency support method for doubly-fed wind turbine generators according to claim 3, characterized in that, According to the disturbance factor k d Adjust the output power reference value of the wind turbine Specifically: in, This is a coefficient representing the output power of the wind turbine in MPPT mode. This refers to the rotor speed of the wind turbine. This represents the power increment of the wind turbine at the initial moment of the disturbance.

5. The adaptive short-time frequency support method for doubly-fed wind turbine generators according to claim 3, characterized in that, Disturbance factor k d for: in, Let be the rate of change of the system's frequency at the initial moment of the disturbance. t For time.

6. The adaptive short-time frequency support method for doubly-fed wind turbine generators according to claim 3, characterized in that, When the output power reaches its maximum value, it begins to decrease; its power reference value. for: in, , These represent the initial rotor speed and the minimum rotor speed, respectively. This refers to the output power of the wind turbines in section AB. This refers to the rotor speed of the wind turbine. This represents the minimum output power of the wind turbine.

7. The adaptive short-time frequency support method for doubly-fed wind turbine generators according to claim 6, characterized in that, Output power of wind turbine units in section AB P 1. The following conditions must be met: in, This is the torque power limit.

8. The adaptive short-time frequency support method for doubly-fed wind turbine generators according to claim 1, characterized in that, Output power reference value of exponential function decay mechanism for: in, 、 These represent the rotational speed at point C and the corresponding time. a The constant coefficient is negative. The initial rotor speed, t For time.

9. The adaptive short-time frequency support method for doubly-fed wind turbine generators according to claim 1, characterized in that, Wind turbine output power and maximum power point tracking power The method for determining intersection is as follows: Real-time acquisition of the current rotor speed and corresponding output power of the wind turbine, and calculation of the current rotor speed at which the power output is calculated. When the two values ​​are equal, they are considered to intersect.

10. An adaptive short-time frequency support system for a doubly-fed wind turbine generator, characterized in that, include: The tracking module controls the wind turbine to be in maximum power point tracking (MPPT) mode during normal operation, outputting the maximum PPT power that matches the current operating conditions. ; The adjustment module monitors the power system frequency in real time. When the system frequency deviation is detected to exceed the frequency regulation dead zone, the frequency support phase is activated, and the output power of the wind turbine is adaptively adjusted according to the load disturbance level determined by the system frequency change rate. The recovery module, when the wind turbine output power drops to the power value at the start of the frequency support phase, enters the rotor speed recovery phase, introducing an exponential function decay mechanism to smoothly reduce the output power through an exponential function. When the wind turbine output power reaches the maximum power point tracking power... When the two forces intersect, the wind turbine is controlled to switch back to maximum power point tracking mode and return to its initial operating state.

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