Active frequency control method and device for wind power grid-connected systems

Abstract

This invention provides an active frequency control method and apparatus for a wind power grid-connected system. The method includes: collecting grid parameters, frequency parameters, wind turbine parameters, and wind speed parameters from the wind power grid-connected system; constructing a system frequency response equation set based on the collected parameters; determining the maximum releaseable energy and energy frequency regulation support constraints based on the wind turbine parameters, frequency parameters, rotor kinetic energy release power, and captured wind energy loss; controlling rotor kinetic energy release based on the maximum releaseable energy and energy frequency regulation support constraints; controlling the rotor to stop energy release and switching to kinetic energy recovery mode in response to the grid frequency and frequency change rate meeting preset requirements; and evaluating the active frequency control effect of the wind power grid-connected system based on the rotor's kinetic energy utilization rate and preset frequency support indicators.

Description

Technical Field

[0001] The present invention relates to the field of wind power generation technology, and in particular to an active frequency control method and device for a wind power grid-connected system. Background Technology

[0002] Large-scale wind power has become a core component of the global energy transition due to its flexible site selection, abundant resources, and short construction cycle. Especially with the trend of high-proportion renewable energy integration, the scale of wind power grid connection continues to expand. However, wind power connects to the grid through power electronic interfaces, and its output is decoupled from the grid frequency, making it unable to provide passive frequency regulation support like traditional synchronous generators. Furthermore, the replacement of synchronous generators by wind power further reduces the grid's equivalent inertia, leading to exacerbated active power imbalances under disturbances such as sudden load increases and DC blocking. This makes the grid frequency prone to exceeding safe thresholds, significantly increasing frequency stability risks and necessitating active frequency support from wind turbines.

[0003] Existing research largely focuses on designing wind power frequency regulation schemes based on "power-frequency dynamics," with mainstream technologies including droop control and virtual inertia control. These schemes regulate wind turbine output by establishing a mapping relationship between power and frequency deviation / rate of change, but they have significant drawbacks: first, they are prone to causing secondary frequency drops; second, they are highly sensitive to grid parameters such as synchronous machine inertia and governor time constants, making parameter tuning difficult and limiting their adaptability to complex grid scenarios; and third, they fail to quantify the coupling relationship between rotor kinetic energy and frequency response, failing to fully exploit the enormous kinetic energy potential stored in the wind turbine rotor, resulting in low utilization of frequency regulation resources.

[0004] While some studies have attempted to optimize frequency regulation control from an energy perspective, their practical application is insufficient. Some solutions rely on expert experience or measured data to generate control strategies, lacking theoretical modeling support for the energy-frequency coupling mechanism, making it difficult to cover diverse disturbance scenarios. Other solutions require prior knowledge of the disturbance scale or grid governor parameters, but in actual engineering, the magnitude of disturbances and the system's equivalent inertia are difficult to predict in advance, preventing the solutions from being directly implemented. Therefore, there is an urgent need to construct a new wind power frequency regulation method based on the energy-frequency coupling mechanism, which does not require precise grid parameters and can fully utilize rotor kinetic energy, in order to overcome the limitations of existing technologies and improve grid frequency stability. Summary of the Invention

[0005] To address the aforementioned technical problems, embodiments of the present invention provide an active frequency control method for a wind power grid-connected system, comprising: Collect grid parameters, frequency parameters, wind turbine parameters, and wind speed parameters from the wind power grid-connected system; By combining the grid parameters, frequency parameters, wind turbine parameters, and wind speed parameters, a system frequency response equation set is constructed. The system frequency response equation set is used to solve and determine the rotor kinetic energy release power of the wind turbine, capture wind energy loss, and quantify the supporting role of the wind turbine in the active frequency of the wind power grid-connected system. The maximum releaseable energy and energy frequency regulation support constraints are determined by combining the wind turbine parameters, frequency parameters, rotor kinetic energy release power, and wind energy capture loss. The rotor kinetic energy release is controlled based on the maximum releaseable energy and the energy frequency modulation support constraint. In response to the grid frequency and frequency change rate meeting preset requirements, the rotor is controlled to stop releasing energy and switch to kinetic energy recovery mode; The active frequency control effect of the wind power grid-connected system is evaluated based on the rotor's kinetic energy utilization rate and the preset frequency support index.

[0006] In one embodiment, the collection of grid parameters, frequency parameters, wind turbine parameters, and wind speed parameters in the wind power grid-connected system includes: The grid frequency, frequency change rate, equivalent rotor speed of the wind turbine, mechanical power of the wind turbine, and average wind speed in the wind power grid-connected system are collected.

[0007] In one embodiment, constructing a system frequency response equation set by combining the grid parameters, frequency parameters, wind turbine parameters, and wind speed parameters includes: The system frequency response equations include: ; ; ; in, and These are the equivalent inertia coefficient and damping coefficient of the wind power grid-connected system, respectively. For disturbance power, and These represent the power changes of the synchronous machine and the fan, respectively. This is the equivalent disturbance. The time constant of the synchronous speed controller. This represents the primary frequency modulation coefficient of the synchronous machine. This indicates the power output of the wind turbine. This indicates the reduction in wind energy capture. This is the moment of inertia of the fan. The rotational speed of the rotor. For the tip speed ratio, Wind speed at the fan location. It is the wind energy utilization coefficient. Where is the blade radius, This refers to air density.

[0008] In one embodiment, determining the maximum releaseable energy includes: The maximum releaseable energy is determined based on the following formula: ; in, To maximize the energy that can be released, To disturb the steady-state speed of the rotor, To ensure the rotor's safe minimum speed, This is the rotational inertia of the fan.

[0009] In one embodiment, determining the energy modulation constraint includes: ; in, The maximum rate of change of the system frequency after the disturbance occurs. The rate of change of frequency, The equivalent inertia coefficient of the wind power grid-connected system. This represents the disturbance power.

[0010] In one embodiment, the method further includes: A cosine-shaped energy release curve is generated based on the maximum releaseable energy and the energy frequency modulation support constraint. The control of rotor kinetic energy release based on the maximum releaseable energy and energy frequency modulation support constraint includes: The kinetic energy release of the rotor is controlled based on the cosine-shaped energy release curve generated by the maximum releaseable energy and energy frequency modulation support constraint.

[0011] In one embodiment, the cosine-type energy release curve includes:

[0012] in, Died due to frequency regulation The total energy release duration is based on... Make corrections, the aforementioned The rate of change of frequency, This represents the maximum energy that can be released.

[0013] In one embodiment, the step of controlling the rotor to stop energy release and switch to kinetic energy recovery mode in response to the grid frequency and frequency change rate meeting preset requirements includes: When the power grid frequency reaches its lowest point and the frequency change rate is zero, the rotor is controlled to stop releasing energy and switch to kinetic energy recovery mode. The power reference values ​​for the kinetic energy recovery mode include: ; in, This represents the power reference value of the rotor-side converter. This indicates the output power of the fan under the condition of releasing frequency modulation energy to the maximum extent. The power of the fan's MPPT curve. This is the moment when the engine speed recovers and starts.

[0014] In one embodiment, determining the kinetic energy utilization rate of the rotor includes:

[0015] in, For kinetic energy utilization, This refers to the moment when the speed recovery starts or the moment when the energy release ends. To maximize the energy that can be released, This indicates the power output of the wind turbine.

[0016] Another embodiment of the present invention also provides an active frequency control device for a wind power grid-connected system, comprising: The data acquisition module is used to collect grid parameters, frequency parameters, wind turbine parameters, and wind speed parameters in the wind power grid-connected system. The module is used to construct a system frequency response equation set by combining the grid parameters, frequency parameters, wind turbine parameters, and wind speed parameters. The system frequency response equation set is used to solve and determine the rotor kinetic energy release power of the wind turbine, capture wind energy loss, and quantify the supporting role of the wind turbine in the active frequency of the wind power grid-connected system. The determination module is used to determine the maximum releaseable energy and energy frequency regulation support constraints by combining the wind turbine parameters, frequency parameters, rotor kinetic energy release power of the wind turbine, and wind energy capture loss; The first control module is used to control the release of rotor kinetic energy based on the maximum releaseable energy and the energy frequency modulation support constraint. The second control module is used to control the rotor to stop releasing energy and switch to kinetic energy recovery mode in response to the grid frequency and frequency change rate meeting preset requirements. The evaluation module is used to evaluate the active frequency control effect of the wind power grid-connected system based on the kinetic energy utilization rate of the rotor and the preset frequency support index.

[0017] The solution provided by the embodiments of the present invention can effectively solve the problems that existing control cannot quantify the coupling relationship between the kinetic energy of the wind turbine rotor and the grid frequency, resulting in insufficient kinetic energy utilization, and that existing energy perspective control requires predicting disturbances or relies on experience, making it difficult to apply in engineering. The solution enables engineering applications and can efficiently and accurately evaluate the effects of active frequency control and kinetic energy utilization in wind power grid-connected systems.

[0018] Other features and advantages of this application will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0019] The technical solution of this application will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a flowchart illustrating the active frequency control method for a wind power grid-connected system in an embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of a wind farm access system with four turbines and two zones provided in an embodiment of the present invention; Figure 3 A system frequency response model diagram including a wind turbine is provided for embodiments of the present invention; Figure 4 The system frequency response and rotor speed simulation curves provided for embodiments of the present invention; Figure 5 This is a structural block diagram of the active frequency control device for a wind power grid-connected system in an embodiment of the present invention. Detailed Implementation

[0023] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but these are not intended to limit the scope of the invention.

[0024] It should be understood that various modifications can be made to the embodiments disclosed herein. Therefore, the following description should not be considered as limiting, but merely as an example of embodiments. Other modifications within the scope of this disclosure will be apparent to those skilled in the art.

[0025] The accompanying drawings, which are included in and form part of this specification, illustrate embodiments of the present disclosure and, together with the general description of the disclosure given above and the detailed description of the embodiments given below, serve to explain the principles of the disclosure.

[0026] These and other features of the invention will become apparent from the following description of preferred forms of embodiments given as non-limiting examples, with reference to the accompanying drawings.

[0027] It should also be understood that although the invention has been described with reference to some specific examples, those skilled in the art can certainly implement many other equivalent forms of the invention, which have the features described in the claims and are therefore all within the scope of protection defined herein.

[0028] The above and other aspects, features and advantages of this disclosure will become more apparent when taken in conjunction with the accompanying drawings and in view of the following detailed description.

[0029] Specific embodiments of the present disclosure are described thereafter with reference to the accompanying drawings; however, it should be understood that the disclosed embodiments are merely examples of the present disclosure and can be implemented in various ways. Well-known and / or repeated functions and structures are not described in detail to avoid unnecessary or redundant details that could obscure the present disclosure. Therefore, the specific structural and functional details disclosed herein are not intended to be limiting, but merely to serve as the basis and representative basis for the claims to teach those skilled in the art to use the present disclosure in a variety of substantially any suitable detailed structures.

[0030] This specification may use the phrases “in one embodiment,” “in another embodiment,” “in yet another embodiment,” or “in still another embodiment,” all of which may refer to one or more of the same or different embodiments according to this disclosure.

[0031] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0032] like Figure 1 As shown, this embodiment of the invention provides an active frequency control method for a wind power grid-connected system, comprising: S1: Collect grid parameters, frequency parameters, wind turbine parameters, and wind speed parameters from the wind power grid-connected system; S2: Combine the grid parameters, frequency parameters, wind turbine parameters, and wind speed parameters to construct a system frequency response equation set. The system frequency response equation set is used to solve and determine the rotor kinetic energy release power of the wind turbine, capture wind energy loss, and quantify the supporting role of the wind turbine in the active frequency of the wind power grid-connected system. S3: Determine the maximum releaseable energy and energy frequency regulation support constraints by combining the aforementioned wind turbine parameters, frequency parameters, rotor kinetic energy release power of the wind turbine, and wind energy capture loss; S4: Control the release of rotor kinetic energy based on the maximum releaseable energy and energy frequency modulation support constraint; S5: In response to the grid frequency and frequency change rate meeting the preset requirements, control the rotor to stop releasing energy and switch to kinetic energy recovery mode; S6: Evaluate the active frequency control effect of the wind power grid-connected system based on the kinetic energy utilization rate of the rotor and the preset frequency support index.

[0033] The solution presented in this embodiment addresses the problems of existing control methods failing to quantify the coupling relationship between wind turbine rotor kinetic energy and grid frequency, leading to insufficient kinetic energy utilization, and the need for predicting disturbances or relying on experience in existing energy-perspective control, making them difficult to apply in engineering. Specifically, to address the issues of reduced grid inertia due to large-scale wind power grid connection, the susceptibility of existing power-frequency perspective frequency modulation methods to secondary frequency drops, and insufficient kinetic energy utilization, this embodiment constructs an energy-frequency coupling model by real-time acquisition of parameters such as grid frequency, frequency change rate, and wind turbine rotor speed to decouple rotor kinetic energy release from wind energy capture losses. Furthermore, the design incorporates rotor kinetic energy release control based on maximum releaseable energy and energy frequency modulation support constraints, achieving maximum utilization of rotor kinetic energy; while the adoption of a speed recovery strategy effectively avoids secondary frequency drops and eliminates the need for precise grid parameters.

[0034] Simulation verification using MatPSST shows that, under load disturbances of 20MW and 50MW, the method in this embodiment can achieve a minimum grid frequency of 49.64Hz and 49.39Hz respectively, with a kinetic energy utilization rate of over 96%. Therefore, it effectively improves the grid frequency stability and is suitable for high-penetration wind power grid connection scenarios.

[0035] In one embodiment, the collection of grid parameters, frequency parameters, wind turbine parameters, and wind speed parameters in the wind power grid-connected system includes: S101: Collect the grid frequency, frequency change rate, equivalent rotor speed of the wind turbine, mechanical power of the wind turbine, and average wind speed in the wind power grid-connected system.

[0036] Of course, other relevant parameters can also be collected, not limited to those mentioned above. In practical applications, these parameters can be collected in real time or periodically.

[0037] Furthermore, the construction of the system frequency response equation set by combining the grid parameters, frequency parameters, wind turbine parameters, and wind speed parameters includes: The system frequency response equations include: ; ; ; in, and These are the equivalent inertia coefficient and damping coefficient of the wind power grid-connected system, respectively. The disturbance power is a constant greater than zero in this embodiment. and These represent the power changes of the synchronous machine and the fan, respectively. This is the equivalent disturbance. The time constant of the synchronous speed controller. This represents the primary frequency modulation coefficient of the synchronous machine. This indicates the power output of the wind turbine. This indicates the reduction in wind energy capture. This is the moment of inertia of the fan. The rotational speed of the rotor. For the tip speed ratio, Wind speed at the fan location. It is the wind energy utilization coefficient. Where is the blade radius, This refers to air density.

[0038] The equations in this embodiment are actually the equations corresponding to the system frequency response curve from an energy perspective. By decoupling the energy separately, the role of frequency-modulated energy in the system frequency response can be easily analyzed. During the frequency modulation process of the wind turbine, the negative impact of the rotor speed decrease can be combined with the system disturbance power to obtain an equivalent time-varying disturbance. Therefore, the system frequency can be considered as a dynamic response to a time-varying disturbance. This indicates that the fan rotor provides short-term frequency support to the system by releasing its own kinetic energy. and There is coupling between them, and the actual value is related to the frequency regulation strategy applied by the wind turbine.

[0039] After obtaining the above set of response equations, solving these equations yields the rotor kinetic energy release power. With captured wind energy loss The system can then calculate and determine the maximum releaseable energy by combining the parameters obtained from the solution. The solution process includes: The maximum releaseable energy is determined based on the following formula: ; in, To maximize the energy that can be released, To disturb the steady-state speed of the rotor, To ensure the rotor's safe minimum speed, This is the rotational inertia of the fan.

[0040] Further, determining the energy frequency modulation constraint includes: ; in, The maximum rate of change of the system frequency after the disturbance occurs. The rate of change of frequency, The equivalent inertia coefficient of the wind power grid-connected system. This represents the disturbance power.

[0041] The above constraints effectively fulfill the three requirements of wind turbine frequency regulation control: maximum energy support; no secondary frequency drop; and low requirements on grid parameters. Under these constraints, the energy release curve for wind turbine frequency regulation can be designed, facilitating subsequent application of frequency regulation control and analysis and verification of its effects.

[0042] For example, in one embodiment, the method further includes: S7: Generate a cosine-type energy release curve based on the maximum releaseable energy and the energy frequency modulation support constraint; The control of rotor kinetic energy release based on the maximum releaseable energy and energy frequency modulation support constraint includes: S401: Control the kinetic energy release of the rotor based on the cosine energy release curve generated by the maximum releaseable energy and energy frequency modulation support constraint.

[0043] In other words, in this embodiment, the control of the kinetic energy release of the wind turbine rotor is based on the cosine energy release curve obtained by solving, and the control effect is significantly improved.

[0044] Specifically, in this embodiment, the cosine-shaped energy release curve includes:

[0045] in, Died due to frequency regulation The total energy release duration is based on... Make corrections, the aforementioned The rate of change of frequency, This represents the maximum energy that can be released.

[0046] At the moment of disturbance, the synchronous generator and wind turbine have not yet responded, and the system frequency change rate is at its maximum. Since it is difficult to know in advance the magnitude of the grid disturbance and the equivalent inertia of the system at the moment of the fault, the maximum value of this frequency change rate is mainly obtained through real-time measurement. At this time, the release of wind turbine frequency regulation resources is zero. When the system frequency change rate becomes zero, all wind turbine frequency regulation resources are released, achieving maximum energy support for the grid. Furthermore, the rate of change of the wind turbine's frequency regulation support power should be zero, thus effectively avoiding a secondary drop in system frequency caused by the termination of frequency regulation support control.

[0047] For example, taking a 100MW wind farm connected to a four-unit, two-area system as an example, such as Figure 2 As shown, simulation verification is performed; where Figure 3The system frequency response (SFR) model including the wind turbine is shown. Since the specific coupling relationship between the wind turbine's frequency regulation energy and the captured wind energy is affected by the frequency regulation control scheme, for detailed analysis, the wind turbine is set to participate in the frequency regulation control using integrated inertia control. The droop coefficients kd in the integrated inertia control of the wind turbine are set to 70, 65, 60, 55, and 50, respectively, yielding the corresponding system frequency response curve and the wind turbine rotor speed variation curve, as shown below. Figure 4 As shown. Figure 4 The simulation curves of the system frequency response model under different droop coefficients are shown in the figure. As the droop coefficient in the integrated control of the wind turbine gradually increases from 50 to 65, the wind turbine releases more rotor energy during frequency regulation, providing longer-term and higher-power support for the system frequency. The minimum frequency point gradually shifts upward, and the time for the system frequency to reach the minimum point gradually lags behind, indicating that the frequency regulation effect of the wind turbine is getting better and better. The above analysis shows that improving the utilization rate of wind turbine frequency regulation resources is an effective way to improve the frequency regulation support effect.

[0048] right Figure 4 Analysis of the simulation curves at kd=65 and kd=70 shows that further increasing the release of rotor kinetic energy delays the time it takes for the system frequency to reach its lowest point. However, due to the reduced wind energy capture, the equivalent disturbance Pdeq of the system increases, and the lowest frequency point shifts downward. This analysis indicates that while increasing the kinetic energy released by the turbine rotor to support the system frequency is necessary, the negative impact of the reduced mechanical power for wind energy capture due to the decrease in rotational speed must also be considered. Overall, improving the utilization rate of the turbine rotor kinetic energy during frequency regulation is crucial for improving the frequency regulation support effect. The impact of wind energy capture loss during the release of turbine rotor kinetic energy needs to be analyzed in conjunction with the specific frequency regulation control scheme. A good wind turbine frequency regulation scheme design should maximize the frequency regulation potential of the turbine while minimizing the negative impact of wind energy capture loss.

[0049] After controlling the rotor kinetic energy release based on the curve, the kinetic energy release status is monitored in real time. The response that the grid frequency and frequency change rate meet preset requirements, controlling the rotor to stop energy release, and switching to kinetic energy recovery mode includes: S501: In response to the grid frequency reaching its lowest point and the frequency change rate being zero, control the rotor to stop releasing energy and switch to kinetic energy recovery mode; The power reference values ​​for the kinetic energy recovery mode include: ; in, This represents the power reference value of the rotor-side converter. This indicates the output power of the fan under the condition of releasing frequency modulation energy to the maximum extent. The power of the fan's MPPT curve. This is the moment when the engine speed recovers and starts.

[0050] During the recovery phase, the wind turbine speed recovery control is initiated, and the mechanical power captured by the wind turbine exceeds the electromagnetic power, restoring the rotor to the optimal speed for MPPT tracking. Combined with a ramp-type rotor speed recovery strategy, this avoids the problem of the wind turbine absorbing active power from the grid during speed recovery, solving the defect of traditional power-frequency perspective control that easily leads to secondary frequency degradation, and ensuring stable grid frequency recovery.

[0051] Based on the above embodiments, the complete frequency regulation process of the wind turbine is as follows: Phase 1: Frequency Change Rate Measurement Phase. Since current equipment typically takes less than 100ms-200ms to measure the frequency change rate, the fan has not yet begun frequency support control during this phase. The transition from the fan frequency control dead zone to its current state is also completed during this phase.

[0052] Phase Two: The phase during which the frequency change rate gradually decreases to 0. During this period, the synchronous machine gradually increases its power output under the action of the speed governor, and the wind turbine releases its rotor kinetic energy according to the constructed energy release curve to support the grid frequency. The system frequency drops to the lowest point, and the frequency change rate gradually decreases to 0.

[0053] Phase 3: System Frequency Recovery Phase. During this phase, the synchronous machine continues to increase power output, the fan rotor remains at its minimum operating speed, and the system frequency gradually increases.

[0054] Phase Four: Second Frequency Drop Phase. In this phase, the fan speed recovery control is initiated, the mechanical power captured by the fan exceeds the electromagnetic power, and the rotor recovers to the optimal speed for MPPT tracking.

[0055] Phase 5: System frequency returns to steady state. At this point, the fan returns to the MPPT operating mode before frequency regulation, the synchronous machine completes one frequency regulation response, and the system frequency remains stable.

[0056] Determining the kinetic energy utilization rate of the rotor includes:

[0057] in, For kinetic energy utilization, This refers to the moment when the speed recovery starts or the moment when the energy release ends. To maximize the energy that can be released, This indicates the power output of the wind turbine.

[0058] When conducting performance evaluation, the system can assess the effectiveness of active frequency control of the wind power grid-connected system based on the calculated kinetic energy utilization rate and preset evaluation indicators.

[0059] In one preferred embodiment, the system's overall control performs well in frequency regulation under a 20MW disturbance. However, due to parameter tuning issues, it struggles to fully utilize the wind turbine rotor energy, with the lowest rotor energy reaching only around 0.82 pu, failing to fully leverage the wind turbine's frequency regulation potential. In contrast, the control scheme proposed in this embodiment utilizes the wind turbine rotor energy to the maximum extent possible, with the rotor reaching a lower limit of 0.7 pu, thus fully utilizing the frequency regulation potential and achieving the best frequency regulation effect, with the lowest frequency point at 49.64Hz.

[0060] In another preferred embodiment, the system's integrated control releases more frequency modulation energy under larger disturbances, but still does not fully utilize the fan's rotor kinetic energy, with the lowest frequency reaching 49.37Hz, resulting in superior frequency modulation performance. The control scheme proposed in this embodiment achieves maximum energy support under disturbances of varying magnitudes without secondary frequency drops, thus exhibiting the best frequency modulation performance, with the lowest frequency reaching 49.39Hz.

[0061] like Figure 5 As shown, another embodiment of the present invention also provides an active frequency control device for a wind power grid-connected system, comprising: The data acquisition module is used to collect grid parameters, frequency parameters, wind turbine parameters, and wind speed parameters in the wind power grid-connected system. The module is used to construct a system frequency response equation set by combining the grid parameters, frequency parameters, wind turbine parameters, and wind speed parameters. The system frequency response equation set is used to solve and determine the rotor kinetic energy release power of the wind turbine, capture wind energy loss, and quantify the supporting role of the wind turbine in the active frequency of the wind power grid-connected system. The determination module is used to determine the maximum releaseable energy and energy frequency regulation support constraints by combining the wind turbine parameters, frequency parameters, rotor kinetic energy release power of the wind turbine, and wind energy capture loss; The first control module is used to control the release of rotor kinetic energy based on the maximum releaseable energy and the energy frequency modulation support constraint. The second control module is used to control the rotor to stop releasing energy and switch to kinetic energy recovery mode in response to the grid frequency and frequency change rate meeting preset requirements. The evaluation module is used to evaluate the active frequency control effect of the wind power grid-connected system based on the kinetic energy utilization rate of the rotor and the preset frequency support index.

[0062] In one embodiment, the collection of grid parameters, frequency parameters, wind turbine parameters, and wind speed parameters in the wind power grid-connected system includes: The grid frequency, frequency change rate, equivalent rotor speed of the wind turbine, mechanical power of the wind turbine, and average wind speed in the wind power grid-connected system are collected.

[0063] In one embodiment, constructing a system frequency response equation set by combining the grid parameters, frequency parameters, wind turbine parameters, and wind speed parameters includes: The system frequency response equations include: ; ; ; in, and These are the equivalent inertia coefficient and damping coefficient of the wind power grid-connected system, respectively. For disturbance power, and These represent the power changes of the synchronous machine and the fan, respectively. This is the equivalent disturbance. The time constant of the synchronous speed controller. This represents the primary frequency modulation coefficient of the synchronous machine. This indicates the power output of the wind turbine. This indicates the reduction in wind energy capture. This is the moment of inertia of the fan. The rotational speed of the rotor. For the tip speed ratio, Wind speed at the fan location. It is the wind energy utilization coefficient. Where is the blade radius, This refers to air density.

[0064] In one embodiment, determining the maximum releaseable energy includes: The maximum releaseable energy is determined based on the following formula: ; in, To maximize the energy that can be released, To disturb the steady-state speed of the rotor, To ensure the rotor's safe minimum speed, This is the rotational inertia of the fan.

[0065] In one embodiment, determining the energy modulation constraint includes: ; in, The maximum rate of change of the system frequency after the disturbance occurs. The rate of change of frequency, The equivalent inertia coefficient of the wind power grid-connected system. This represents the disturbance power.

[0066] In one embodiment, the method further includes: A cosine-shaped energy release curve is generated based on the maximum releaseable energy and the energy frequency modulation support constraint. The control of rotor kinetic energy release based on the maximum releaseable energy and energy frequency modulation support constraint includes: The kinetic energy release of the rotor is controlled based on the cosine-shaped energy release curve generated by the maximum releaseable energy and energy frequency modulation support constraint.

[0067] In one embodiment, the cosine-type energy release curve includes:

[0068] in, Died due to frequency regulation The total energy release duration is based on... Make corrections, the aforementioned The rate of change of frequency, This represents the maximum energy that can be released.

[0069] In one embodiment, the step of controlling the rotor to stop energy release and switch to kinetic energy recovery mode in response to the grid frequency and frequency change rate meeting preset requirements includes: When the power grid frequency reaches its lowest point and the frequency change rate is zero, the rotor is controlled to stop releasing energy and switch to kinetic energy recovery mode. The power reference values ​​for the kinetic energy recovery mode include: ; in, This represents the power reference value of the rotor-side converter. This indicates the output power of the fan under the condition of releasing frequency modulation energy to the maximum extent. The power of the fan's MPPT curve. This is the moment when the engine speed recovers and starts.

[0070] In one embodiment, determining the kinetic energy utilization rate of the rotor includes:

[0071] in, For kinetic energy utilization, This refers to the moment when the speed recovery starts or the moment when the energy release ends. To maximize the energy that can be released, This indicates the power output of the wind turbine.

[0072] Another embodiment of the present invention also provides an electronic device, comprising: One or more processors; Memory, configured to store one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the active frequency control method for wind power grid-connected systems as described in any of the above descriptions.

[0073] Furthermore, one embodiment of the present invention also provides a storage medium storing a computer program thereon, which, when executed by a processor, implements the active frequency control method for a wind power grid-connected system as described above. It should be understood that the various solutions in this embodiment have the corresponding technical effects in the above-described method embodiments, and will not be repeated here.

[0074] Furthermore, embodiments of the present invention also provide a computer program product, which is tangibly stored on a computer-readable medium and includes computer-readable instructions that, when executed, cause at least one processor to perform an active frequency control method for a wind power grid-connected system, such as the one described in the embodiments above.

[0075] It should be noted that the computer storage medium of the present invention can be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. A computer-readable medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, system, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, a random access storage medium (RAM), a read-only storage medium (ROM), an erasable programmable read-only storage medium (EPROM or flash memory), an optical fiber, a portable compact disk read-only storage medium (CD-ROM), an optical storage medium, a magnetic storage medium, or any suitable combination thereof. In the present invention, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system, or device. In the present invention, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-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. Computer-readable signal media can also be any computer-readable medium other than computer-readable storage media, which can send, propagate, or transmit a program configured for use by or in connection with an instruction execution system, system, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wireless, antenna, optical fiber, RF, etc., or any suitable combination thereof.

[0076] Furthermore, those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0077] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. 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 illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A system that specifies functions in one or more boxes.

[0078] 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 an instruction set implemented in a process. Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0079] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of protection of this application is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of one or more embodiments of this application as described above, which are not provided in detail for the sake of brevity.

Claims

1. An active frequency control method for a wind power grid-connected system, characterized in that, include: Collect grid parameters, frequency parameters, wind turbine parameters, and wind speed parameters from the wind power grid-connected system; By combining the grid parameters, frequency parameters, wind turbine parameters, and wind speed parameters, a system frequency response equation set is constructed. The system frequency response equation set is used to solve and determine the rotor kinetic energy release power of the wind turbine, capture wind energy loss, and quantify the supporting role of the wind turbine in the active frequency of the wind power grid-connected system. The maximum releaseable energy and energy frequency regulation support constraints are determined by combining the wind turbine parameters, frequency parameters, rotor kinetic energy release power, and wind energy capture loss. The rotor kinetic energy release is controlled based on the maximum releaseable energy and the energy frequency modulation support constraint. In response to the grid frequency and frequency change rate meeting preset requirements, the rotor is controlled to stop releasing energy and switch to kinetic energy recovery mode; The active frequency control effect of the wind power grid-connected system is evaluated based on the kinetic energy utilization rate of the rotor and the preset frequency support index. The construction of the system frequency response equation set by combining the power grid parameters, frequency parameters, wind turbine parameters, and wind speed parameters includes: The system frequency response equations include: ； ； ； in, and These are the equivalent inertia coefficient and damping coefficient of the wind power grid-connected system, respectively. For disturbance power, and These represent the power changes of the synchronous machine and the fan, respectively. This is the equivalent disturbance. The time constant of the synchronous speed controller. This is the primary frequency modulation coefficient of the synchronous machine. This indicates the power output of the wind turbine. This indicates the reduction in wind energy capture. This is the moment of inertia of the fan. The rotational speed of the rotor. For the tip speed ratio, Wind speed at the fan location. It is the wind energy utilization coefficient. Where is the blade radius, This refers to air density.

2. The active frequency control method for wind power grid-connected systems according to claim 1, characterized in that, The data collected from the wind power grid-connected system includes grid parameters, frequency parameters, wind turbine parameters, and wind speed parameters, including: The grid frequency, frequency change rate, equivalent rotor speed of the wind turbine, mechanical power of the wind turbine, and average wind speed in the wind power grid-connected system are collected.

3. The active frequency control method for wind power grid-connected systems according to claim 1, characterized in that, Determining the maximum releaseable energy includes: The maximum releaseable energy is determined based on the following formula: ； in, To maximize the energy that can be released, To disturb the steady-state speed of the rotor, To ensure the rotor's safe minimum speed, This is the rotational inertia of the fan.

4. The active frequency control method for a wind power grid-connected system according to claim 1, characterized in that, Determining the energy frequency modulation constraint includes: ； in, The maximum rate of change of the system frequency after the disturbance occurs. The rate of change of frequency, The equivalent inertia coefficient of the wind power grid-connected system. This represents the disturbance power.

5. The active frequency control method for a wind power grid-connected system according to claim 1, characterized in that, The method further includes: A cosine-shaped energy release curve is generated based on the maximum releaseable energy and the energy frequency modulation support constraint. The control of rotor kinetic energy release based on the maximum releaseable energy and energy frequency modulation support constraint includes: The kinetic energy release of the rotor is controlled based on the cosine-shaped energy release curve generated by the maximum releaseable energy and energy frequency modulation support constraint.

6. The active frequency control method for a wind power grid-connected system according to claim 5, characterized in that, The cosine-type energy release curve includes: in, Died due to frequency regulation The total energy release duration is based on... Make corrections, the aforementioned The rate of change of frequency, This represents the maximum energy that can be released.

7. The active frequency control method for a wind power grid-connected system according to claim 1, characterized in that, The response to the grid frequency and frequency change rate meeting preset requirements, controlling the rotor to stop energy release and switching to kinetic energy recovery mode, includes: When the power grid frequency reaches its lowest point and the frequency change rate is zero, the rotor is controlled to stop releasing energy and switch to kinetic energy recovery mode. The power reference values ​​for the kinetic energy recovery mode include: ； in, This represents the power reference value of the rotor-side converter. This indicates the output power of the fan under the condition of releasing frequency modulation energy to the maximum extent. The power of the fan's MPPT curve. This is the moment when the engine speed recovers and starts.

8. The active frequency control method for a wind power grid-connected system according to claim 1, characterized in that, Determining the kinetic energy utilization rate of the rotor includes: in, For kinetic energy utilization, This refers to the moment when the speed recovery starts or the moment when the energy release ends. To maximize the energy that can be released, This indicates the power output of the wind turbine.

9. An active frequency control device for a wind power grid-connected system, characterized in that, This method is used to implement the active frequency control method for wind power grid-connected systems as described in any one of claims 1-8.

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