A Grid Simulation Method, System, Device and Medium for Wideband Oscillation of a Wind Turbine Generator Set Connected to the Grid

Abstract

The present invention provides a method, system, device and medium for simulating a grid with wide-frequency oscillation in the grid connection of a wind turbine generator set, belonging to the technical field of new energy grid connection in a power system. The method includes: performing frequency sweeping on the grid side part of the physical wind turbine generator set grid connection system to obtain the dq impedance characteristic curve in the full frequency band; processing the dq impedance characteristic curve in the full frequency band by frequency segmentation; using the least squares method to perform rational function fitting on the dq impedance characteristic curve in each frequency band, and equivalent the grid side part of the physical wind turbine generator set grid connection system to an RLC branch; constructing an impedance circuit, a main circuit and a signal processing module for each frequency band to complete the construction of the wide-frequency oscillation condition simulation circuit; reproducing the wide-frequency impedance dynamic characteristics of the physical wind turbine generator set grid connection system through the wide-frequency oscillation condition simulation circuit, so as to detect the grid connection stability of the physical wind turbine generator set. The present invention avoids the limitation of the simulation accuracy of the grid simulator based on the topology of the power electronic converter by the switching frequency and control accuracy.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy grid connection in power systems, and particularly relates to a method, system, device and medium for simulating a wide-frequency oscillation power grid for wind turbine grid connection. Background Art

[0002] With the development of new energy represented by wind power, the power system is developing towards a direction of high proportion of new energy and high proportion of power electronics. The multi-time scale, diverse equipment complex coupling interaction and wide-frequency oscillation characteristics of the current power system are becoming increasingly prominent, resulting in the power system being prone to wide-frequency oscillations of several hertz to thousands of hertz, seriously threatening the safe and stable operation of the power system.

[0003] Before leaving the factory, wind turbines need to undergo grid connection stability tests. The wind turbines are placed in a simulated power grid environment to evaluate whether the grid connection oscillation characteristics of the wind turbines meet the expectations. Existing grid simulators usually use power electronic converters as the basic topology and achieve the simulation of grid impedance characteristics by formulating specific control strategies. However, the control structure of this scheme is relatively complex, and it is restricted by the device switching frequency, as well as the accuracy and stability of the control system, resulting in limited simulated impedance order and insufficient impedance accuracy of the simulation, and it cannot accurately reflect the impedance characteristics of complex power systems. Therefore, most of these grid simulators are only suitable for simulating the grid line impedance with a lower order, and are not applicable to complex grid connection systems with high-order impedance characteristics such as the system for sending wind power through flexible DC transmission. In addition, there are also grid simulators that use hardware-in-the-loop simulation to simulate the grid connection system impedance, but because there are still errors in the grid connection system model compared with the actual grid connection system, it is also impossible to ensure accurate simulation of the grid connection system impedance in the full frequency band. Summary of the Invention

[0004] In a first aspect, an embodiment of the present application provides a method for simulating a wide-frequency oscillation power grid for wind turbine grid connection, including the following steps:

[0005] S1. Sweep the frequency of the grid side part of the physical wind turbine grid connection system to obtain the full-frequency dq impedance characteristic curve of the grid side part of the physical wind turbine grid connection system;

[0006] S2. Process the full-frequency dq impedance characteristic curve by frequency segmentation to ensure that the bandwidth of each frequency band is the largest when determining the order required for fitting with a rational function, and the order required for fitting with a rational function is the smallest when determining the bandwidth of each frequency band;

[0007] S3. Use the least squares method to perform rational function fitting on the dq impedance characteristic curve of each frequency band, and equivalent the grid side part of the physical wind turbine grid connection system to an RLC branch according to the fitted rational function expression;

[0008] S4. Construct an impedance circuit characterized by a series connection of an oscillating current source and an equivalent RLC branch for each frequency band, construct a main circuit characterized by a series connection of a power frequency voltage source and an oscillating voltage source, and construct a signal processing module for virtually connecting the main circuit and the impedance circuit to complete the construction of a broadband oscillation condition simulation circuit;

[0009] S5. Reproduce the broadband impedance dynamic characteristics of the physical wind turbine grid-connected system through the broadband oscillation condition simulation circuit, and detect the grid connection stability of the physical wind turbine.

[0010] Furthermore, the specific steps of step S1 are as follows:

[0011] S11. Determine the number of experiments N, where N ≥ 2;

[0012] S12. Inject harmonic disturbance current into the physical wind turbine grid-connected system in each experiment;

[0013] S13. Change the frequency of the injected harmonic disturbance current according to the set amplitude, and obtain the full-frequency dq impedance characteristic curve of the grid side part of the physical wind turbine grid-connected system output according to the sending mode through measurement and calculation; the sending modes include flexible DC transmission sending, power frequency AC sending, diode uncontrolled rectifier sending, and frequency division power transmission sending;

[0014] S14. Compare the full-frequency dq impedance characteristic curves obtained from N experiments, and judge that the difference between each full-frequency dq impedance characteristic curve is less than the set amplitude;

[0015] If so, the test result is credible, and proceed to step S2;

[0016] If not, the test result is not credible, and return to step S12.

[0017] Furthermore, the specific steps of step S2 are as follows:

[0018] S21. Preliminarily divide the full-frequency dq impedance characteristic curve into several frequency bands;

[0019] S22. Fit each frequency band with a rational function to determine the required order of fitting;

[0020] S23. Judge whether the required order of fitting for each frequency band is less than the set order threshold;

[0021] If so, proceed to step S25;

[0022] If not, proceed to step S24;

[0023] S24. Divide the full-frequency dq impedance characteristic curve into frequency bands again in the way of reducing the frequency bandwidth, and return to step S22;

[0024] S25. Determine whether the frequency bands can be merged under the condition of fixing the required order of fitting for each current frequency band;

[0025] If so, go to step S26;

[0026] If not, determine the division of each frequency band and go to step S3;

[0027] S26. Merge the frequency bands to obtain the final frequency band division.

[0028] Further, the specific steps of step S3 are as follows:

[0029] S31. Select one of the frequency bands divided from the dq impedance characteristic curve of the full frequency band as the test frequency band;

[0030] S32. Use the least squares method to perform rational function fitting on the dq impedance characteristic curve segment corresponding to the test frequency band, ensure the fitting accuracy and perform order reduction to obtain a 2×2 order dq impedance rational function matrix;

[0031] S33. Express each impedance rational function in the 2×2 order dq rational function matrix as a real pole part, a conjugate complex pole part, a constant term, and a linear term part;

[0032] S34. Perform RLC branch equivalence on the 2×2 order dq impedance rational function matrix to obtain a real pole term branch, a conjugate complex pole term branch, a constant term, and a linear term branch, and then combine the series or parallel implementation forms to obtain four equivalent RLC branches under the determined implementation form.

[0033] Further, the specific steps of step S34 are as follows:

[0034] S341. Determine the implementation form;

[0035] If it is a series implementation form, go to step S342;

[0036] If it is a parallel implementation form, go to step S344;

[0037] S342. Connect the real pole term branch, the conjugate complex pole term branch, and the constant term and linear term branches in series;

[0038] S343. Use a resistor and a capacitor in parallel to represent the real pole term branch, use a resistor in series with an inductor and then in parallel with a resistor and a capacitor to represent the conjugate complex pole term branch, and use a resistor and an inductor in series to represent the constant term and linear term branches to obtain four equivalent RLC branches in the series implementation form;

[0039] S344. Connect the real pole term branch, the conjugate complex pole term branch, and the constant term and linear term branches in parallel;

[0040] S345. Use a resistor in series with an inductor to represent the real pole term branch, use a resistor in parallel with a capacitor and then in series with an inductor and a resistor to represent the conjugate complex pole term branch, and use a resistor in parallel with a capacitor to represent the constant term and first-order term branches, to obtain four equivalent RLC branches in the parallel implementation form.

[0041] Furthermore, the specific steps of step S4 are as follows:

[0042] S41. Connect a controlled oscillating current source in series with each of the four equivalent RLC branches to obtain four sub-circuits as impedance circuits;

[0043] S42. Connect a power frequency voltage source and a controlled oscillating voltage source in series to form the main circuit, leave an external connection port for connecting the physical wind turbine to be measured, and set the voltage value of the power frequency voltage source to the grid-side three-phase AC voltage under the stable operating condition of the physical wind turbine grid connection system;

[0044] S43. Construct a signal processing module including a voltage signal processing unit and a current signal processing unit;

[0045] S44. Convert the current control signal collected from the main circuit into an oscillating current signal through the current signal processing unit to control the controlled oscillating current sources in each sub-circuit of the impedance circuit and output dq-axis oscillating currents;

[0046] S45. Convert the dq-axis oscillating voltages generated by each sub-circuit according to the dq-axis oscillating currents into oscillating voltage signals through the voltage signal processing unit and feedback them to the main circuit to control the controlled oscillating voltage source to output three-phase oscillating voltages, and load them at the AC side port of the physical wind turbine to generate oscillating currents, completing the construction of the wide-frequency oscillation condition simulation circuit.

[0047] Furthermore, the specific steps of step S5 are as follows:

[0048] S51. Based on the constructed wide-frequency oscillation condition simulation circuit, reproduce the oscillation condition and change the control parameters of the physical wind turbine;

[0049] S52. Identify whether the oscillation characteristics of the wind turbine are consistent with the expected characteristics;

[0050] If yes, go to step S53;

[0051] If no, go to step S56;

[0052] S53. Judge whether each frequency band has been tested;

[0053] If yes, go to step S55;

[0054] If not, go to step S54;

[0055] S54. Select one of the frequency bands divided from the full - band dq impedance characteristic curve as the test frequency band, and return to step S32;

[0056] S55. Determine that the physical wind turbine meets the requirements, the test passes, and end;

[0057] S56. Determine that the test of the physical wind turbine fails.

[0058] In a second aspect, an embodiment of the present application further provides a wide - frequency oscillation power grid simulation system for a wind turbine grid connection, including:

[0059] A full - band impedance characteristic curve acquisition unit, configured to perform frequency sweeping on the grid - side part of the physical wind turbine grid - connection system to obtain the full - band dq impedance characteristic curve of the grid - side part of the physical wind turbine grid - connection system;

[0060] An impedance characteristic curve segmentation unit, configured to segment the full - band dq impedance characteristic curve according to frequency, ensure that the bandwidth of each frequency band is the largest when determining the required order of the rational function for fitting, and the required order of the rational function for fitting is the smallest when determining the bandwidth of each frequency band;

[0061] An RLC branch equivalent unit, configured to perform rational function fitting on the dq impedance characteristic curve of each frequency band using the least - squares method, and equivalent the grid - side part of the physical wind turbine grid - connection system to an RLC branch according to the fitted rational function expression;

[0062] An analog circuit construction unit, configured to construct an impedance circuit characterized by a series connection of an oscillating current source and an equivalent RLC branch for each frequency band, construct a main circuit characterized by a series connection of a power - frequency voltage source and an oscillating voltage source, and construct a signal processing module for virtually connecting the main circuit and the impedance circuit to complete the construction of the wide - frequency oscillation condition simulation circuit;

[0063] An oscillation condition reproduction unit, configured to reproduce the wide - frequency impedance dynamic characteristics of the physical wind turbine grid - connection system through the wide - frequency oscillation condition simulation circuit, and detect the grid - connection stability of the physical wind turbine.

[0064] In a third aspect, an embodiment of the present application further provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the steps of the wide - frequency oscillation power grid simulation method for a wind turbine grid connection as described in the first aspect are implemented.

[0065] In a fourth aspect, an embodiment of the present application further provides a storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the wide - frequency oscillation power grid simulation method for a wind turbine grid connection as described in the first aspect are implemented.

[0066] As can be seen from the above technical solutions, the present invention has the following advantages:

[0067] In the wind turbine grid-connected broadband oscillation power grid simulation method, system, device and medium provided by the present application, the impedance of the complex grid-connected system is equivalent to an RLC branch, avoiding the problem that the impedance order and accuracy simulated by the power grid simulator based on the power electronic converter topology are limited by the device switching frequency and control accuracy; while improving the impedance simulation accuracy of the grid-connected system, it does not require complex controller debugging, and can simulate the impedance of complex grid-connected systems such as flexible DC transmission systems that are not applicable to the power electronic converter type power grid simulator, providing a good test environment for the grid-connected stability test of wind turbines and broadening the test scenarios. The present application obtains the full-band real impedance characteristics from the actual physical grid-connected system, avoiding the problem that the impedance characteristic accuracy simulated by the power grid simulator based on hardware-in-the-loop simulation is limited due to the error between the deduced grid-connected model and the actual system. The simulated impedance characteristics are closer to the real grid-connected system impedance characteristics, and at the same time, the simulation range can cover the full band, which is more suitable for the simulation of the broadband oscillation conditions of wind turbine grid connection. The grid-connected stability test results obtained by the present invention are also more persuasive. Description of the Drawings

[0068] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for the description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0069] Figure 1 It is a schematic flow chart of the first embodiment of the wind turbine grid-connected broadband oscillation power grid simulation method of the present invention.

[0070] Figure 2 It is a schematic diagram of the wind turbine grid-connected broadband oscillation power grid simulation system of the present invention.

[0071] Figure 3 It is a topological diagram of the RLC branch in the series implementation form of the present invention.

[0072] Figure 4 It is a topological diagram of the RLC branch in the parallel implementation form of the present invention.

[0073] Figure 5 It is a circuit structure diagram for simulating broadband oscillation conditions of the present invention.

[0074] Figure 6 It is a structure diagram of the current signal processing unit of the present invention.

[0075] Figure 7This is the structural diagram of the voltage signal processing unit of the present invention. Detailed implementation manners

[0076] In the following, the specific steps of the grid simulation method for the grid-connected broadband oscillation of a wind turbine will be described in detail, and various embodiments of the present disclosure will be described more comprehensively. The present disclosure may have various embodiments, and adjustments and changes may be made therein. However, it should be understood that there is no intention to limit the various embodiments of the present disclosure to the specific embodiments disclosed herein, but the present disclosure should be understood to cover all adjustments, equivalents, and / or alternative solutions that fall within the spirit and scope of the various embodiments of the present disclosure.

[0077] Exemplarily, with the rapid development of new energy sources such as wind power, the power system is gradually transforming towards a high proportion of new energy and a high proportion of power electronics. During this transformation process, the power system exhibits characteristics such as multi-time scales, complex coupling interactions between diverse devices, and broadband oscillations. These characteristics exacerbate the stability challenges of the power system, especially the broadband oscillation problem, whose frequency range may cover several hertz to several kilohertz, posing a serious threat to the safe and stable operation of the power system.

[0078] As an important part of new energy power generation, wind turbines need to undergo grid connection stability tests before leaving the factory to evaluate whether their grid connection oscillation characteristics meet expectations. Existing grid simulators usually adopt power electronic converters as the basic topology and simulate the grid impedance characteristics through specific control strategies. However, this solution has many limitations, such as complex control structures, being restricted by device switching frequencies and the accuracy and stability of the control system, resulting in limited simulated impedance orders and insufficient accuracy. Therefore, such grid simulators are mainly suitable for simulating the grid line impedance with a lower order. For complex grid-connected systems with high-order impedance characteristics, such as the system for wind power transmission through flexible DC transmission, their applicability is limited. In addition, there are also grid simulators that use hardware-in-the-loop simulation to simulate the grid-connected system impedance, but due to the limitations of the difference between the model accuracy and the real system, it is impossible to ensure a comprehensive and accurate simulation of the grid-connected system impedance. This limitation further restricts the application of traditional grid simulators in the stability tests of complex grid-connected systems.

[0079] In view of the above problems, this embodiment provides a grid simulation method for the grid-connected broadband oscillation of a wind turbine, which avoids the problems that the simulation accuracy of a grid simulator based on the power electronic converter topology is limited by the switching frequency and control accuracy, and the simulation accuracy of a grid simulator based on hardware-in-the-loop simulation is limited by the error between the theoretical model and the real system, and can detect the grid connection stability of new energy units in a new energy grid-connected system.

[0080] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0081] Please refer to Figure 1 The figure shows a flowchart of a method for simulating a grid-connected wide-frequency oscillation power grid of a wind turbine in a specific embodiment. The method includes the following steps:

[0082] S1. Sweep the frequency of the grid side part of the physical wind turbine grid-connected system to obtain the full-frequency dq impedance characteristic curve of the grid side part of the physical wind turbine grid-connected system;

[0083] It should be noted that through the frequency sweep test, the impedance characteristics of the grid side part of the wind turbine grid-connected system in the full-frequency range can be comprehensively obtained, providing data support for subsequent impedance characteristic analysis and simulation;

[0084] S2. Process the full-frequency dq impedance characteristic curve by frequency segmentation to ensure that the bandwidth of each frequency band is the largest when determining the order required for fitting with a rational function, and the order required for fitting with a rational function is the smallest when determining the bandwidth of each frequency band;

[0085] It should be noted that the segmentation processing can simplify the description of the impedance characteristics. By optimizing the frequency band division, it is ensured that the impedance characteristics can be accurately fitted with a rational function of a lower order within each frequency band, reducing the complexity and calculation amount of the simulation;

[0086] S3. Use the least squares method to perform rational function fitting on the dq impedance characteristic curve of each frequency band, and equivalent the grid side part of the physical wind turbine grid-connected system to an RLC branch according to the fitted rational function expression;

[0087] It should be noted that through the rational function fitting, the complex impedance characteristics are transformed into a simple RLC branch equivalent circuit, which is convenient for the design and implementation of the subsequent simulation circuit;

[0088] S4. Construct an impedance circuit characterized by a series connection of an oscillating current source and an equivalent RLC branch for each frequency band, construct a main circuit characterized by a series connection of a power frequency voltage source and an oscillating voltage source, and construct a signal processing module for virtual connection of the main circuit and the impedance circuit to complete the construction of the wide-frequency oscillation condition simulation circuit;

[0089] It should be noted that by constructing the simulation circuit, the wide-frequency oscillation condition of the wind turbine grid-connected system can be reproduced, providing a realistic test environment for the stability test of the wind turbine;

[0090] S5. Reproduce the broadband impedance dynamic characteristics of the physical wind turbine grid-connected system through a broadband oscillation condition simulation circuit, and detect the grid connection stability of the physical wind turbine.

[0091] It should be noted that through the test of the simulation circuit, it is possible to accurately evaluate whether the oscillation characteristics of the wind turbine under broadband oscillation conditions are consistent with the expected characteristics, ensuring its safety and reliability during grid-connected operation.

[0092] In this embodiment, within the allowable accuracy range, the complex grid-connected system impedance is equivalent to a low-order RLC circuit, and then the broadband oscillation condition is simulated and used in the grid connection stability test link of new energy units such as wind turbines; it avoids the problems that the impedance order and accuracy simulated by the existing oscillation condition simulation method are limited by the device switching frequency and control accuracy, and limited by the error between the theoretical model and the actual system, and is more suitable for the impedance characteristic simulation of complex grid-connected systems such as the wind turbine sending system through flexible DC transmission, with stronger feasibility and wider applicability.

[0093] Furthermore, as a refinement and extension of the specific implementation manner of the above embodiment, in order to fully illustrate the specific implementation process in this embodiment, another method for simulating the broadband oscillation of the wind turbine grid connection is provided, and this method includes the following steps:

[0094] S1. Sweep the grid side part of the physical wind turbine grid-connected system to obtain the full-frequency dq impedance characteristic curve of the grid side part of the physical wind turbine grid-connected system; the specific steps of step S1 are as follows:

[0095] S11. Determine the number of experiments N, N≥2;

[0096] S12. Inject harmonic disturbance current into the physical wind turbine grid-connected system in each experiment;

[0097] S13. Change the frequency of the injected harmonic disturbance current according to the set amplitude, and obtain the full-frequency dq impedance characteristic curve of the grid side part of the physical wind turbine grid-connected system output according to the sending method; the sending methods include sending through flexible DC transmission, sending through industrial frequency AC, sending through diode uncontrolled rectification, and sending through frequency division transmission;

[0098] It should be noted that this application is applicable to the grid connection stability test of new energy units in the new energy grid-connected system. Among them, in addition to the sending through flexible DC transmission, the system sending method can also be various sending methods such as sending through industrial frequency AC, sending through diode uncontrolled rectification, and sending through frequency division transmission;

[0099] S14. Compare the full-frequency dq impedance characteristic curves obtained from N experiments, and judge that the difference between each full-frequency dq impedance characteristic curve is less than the set amplitude;

[0100] If so, the test result is credible, and proceed to step S2;

[0101] If not, the test result is not credible, and return to step S12;

[0102] It should be noted that after determining the number of experiments, select frequency points, inject harmonic disturbances twice at each frequency point in each experiment, and calculate the impedance at each frequency point. By conducting multiple experiments, the differences in experimental results can be compared, thereby evaluating experimental errors and uncertainties; if the results of multiple experiments are similar or consistent, then it can be considered that the measurement results have a high degree of credibility; although increasing the number of injections may provide more data points, it will also correspondingly increase the experimental complexity and cost; therefore, by reasonably designing the experimental scheme, the number of experiments and costs can be minimized while ensuring the accuracy of the measurement results.

[0103] S2. Process the full-band dq impedance characteristic curve by frequency segmentation to ensure that the bandwidth of each frequency band is maximized when determining the required order for fitting with a rational function, and the required order for fitting with a rational function is minimized when determining the bandwidth of each frequency band; the specific steps of step S2 are as follows:

[0104] S21. Initially divide the full-band dq impedance characteristic curve into several frequency bands;

[0105] S22. Fit each frequency band with a rational function to determine the required order for fitting;

[0106] S23. Determine whether the required order for fitting each frequency band is less than the set order threshold;

[0107] If so, proceed to step S25;

[0108] If not, proceed to step S24;

[0109] S24. Re-divide the full-band dq impedance characteristic curve by reducing the frequency bandwidth, and return to step S22;

[0110] S25. Determine whether the frequency bands can be merged under the condition of fixing the required order for fitting each current frequency band;

[0111] If so, proceed to step S26;

[0112] If not, determine the division of each frequency band and proceed to step S3;

[0113] S26. Merge the frequency bands to obtain the final frequency band division;

[0114] It should be noted that according to the complexity of the amplitude and phase changes of the impedance curve, the obtained full-frequency dq impedance characteristic curve is segmented by frequency. The goal is to minimize the order of the rational function fitting while maximizing the bandwidth of each frequency segment. At this time, the complex impedance characteristics of the original HVDC system in the full frequency range are initially reduced in order and disassembled into impedance characteristics in multiple frequency segments.

[0115] S3. Use the least squares method to perform rational function fitting on the dq impedance characteristic curve of each frequency band, and equivalent the grid-side part of the physical wind turbine grid-connected system to an RLC branch according to the fitted rational function expression. The specific steps of step S3 are as follows:

[0116] S31. Select one of the frequency bands divided from the full-frequency dq impedance characteristic curve as the test frequency band.

[0117] S32. Use the least squares method to perform rational function fitting on the dq impedance characteristic curve segment corresponding to the test frequency band, ensure the fitting accuracy and reduce the order, and obtain the following 2×2 order dq impedance rational function matrix:

[0118] (1)

[0119] Among them, s is the frequency of the frequency band;

[0120] S33. Express each impedance rational function in the 2×2 order dq rational function matrix as a real pole part, a conjugate complex pole part, a constant term, and a linear term as follows:

[0121] (2)

[0122] Among them, M is the number of real pole terms, N is the number of conjugate complex pole terms;

[0123] S34. Equivalent the 2×2 order dq impedance rational function matrix to obtain a real pole term branch, a conjugate complex pole term branch, a constant term, and a linear term branch, and then combine them in series or parallel to obtain four equivalent RLC branches in a determined implementation form. The specific steps of step S34 are as follows:

[0124] S341. Determine the implementation form;

[0125] If it is a series implementation form, go to step S342;

[0126] If it is a parallel implementation form, go to step S344;

[0127] S342. Connect the real pole term branch, the conjugate complex pole term branch, and the constant term and linear term branch in series, such asFigure 3 as shown

[0128] S343. Use a resistor and a capacitor in parallel to represent the real - pole - term branch, with the component parameters as shown in formula (3) below. Use a resistor in series with an inductor and then in parallel with a resistor and a capacitor to represent the conjugate - complex - pole - term branch, with the component parameters as shown in formula (4) below. Use a resistor and an inductor in series to represent the constant - term and first - order - term branch, with the component parameters as shown in formula (5) below, to obtain four equivalent RLC branches in series implementation form;

[0129] (3)

[0130] (4)

[0131] (5)

[0132] S344. Parallel the real - pole - term branch, the conjugate - complex - pole - term branch, and the constant - term and first - order - term branch together, as Figure 4 as shown

[0133] S345. Use a resistor and an inductor in series to represent the real - pole - term branch, with the component parameters as shown in formula (6) below. Use a resistor in series with a capacitor and then in parallel with an inductor and a resistor to represent the conjugate - complex - pole - term branch, with the component parameters as shown in formula (7) below. Use a resistor and a capacitor in parallel to represent the constant - term and first - order - term branch, with the component parameters as shown in formula (8) below, to obtain four equivalent RLC branches in parallel implementation form;

[0134] (6)

[0135] (7)

[0136] (8)

[0137] S4. For each frequency band, construct an impedance circuit characterized by an oscillating current source in series with an equivalent RLC branch, construct a main circuit characterized by a power - frequency voltage source in series with an oscillating voltage source, and construct a signal - processing module for virtual connection between the main circuit and the impedance circuit to complete the construction of a wide - frequency - oscillation condition simulation circuit as Figure 5 as shown; The specific steps of step S4 are as follows:

[0138] S41. Connect each of the four equivalent RLC branches in series with a controlled oscillating current source to obtain four sub - circuits as the impedance circuit;

[0139] S42. A main circuit is formed by connecting a power frequency voltage source and a controlled oscillating voltage source in series, leaving an external port for connecting the physical wind turbine to be measured, and setting the voltage value of the power frequency voltage source as the three-phase AC voltage on the grid side under the stable operating condition of the physical wind turbine grid-connected system.

[0140] It should be noted that the stable operating condition is an ideal condition, that is, the physical wind turbine grid-connected system can maintain the stability of parameters such as voltage, current, power, and frequency, and at the same time has good dynamic response capabilities and equipment operating states.

[0141] S43. Construct a signal processing module including a voltage signal processing unit and a current signal processing unit.

[0142] S44. The current control signal collected from the main circuit is converted into an oscillating current signal by the current signal processing unit to control the controlled oscillating current sources of each sub-circuit in the impedance circuit and output the dq-axis oscillating current.

[0143] S45. The dq-axis oscillating voltage generated by each sub-circuit according to the dq-axis oscillating current is converted into an oscillating voltage signal by the voltage signal processing unit and fed back to the main circuit to control the controlled oscillating voltage source to output a three-phase oscillating voltage, which is loaded at the AC side port of the physical wind turbine to generate an oscillating current, completing the construction of the wide-frequency oscillation condition simulation circuit.

[0144] It should be noted that the main circuit is the circuit for connecting the external wind turbine to be measured, which is composed of a power frequency voltage source and an oscillating voltage source connected in series; among them, the power frequency voltage source is an ideal voltage source, and its voltage value is the three-phase AC voltage under the steady-state operation of the VSC-HVDC system, representing the steady-state operation condition of the VSC-HVDC system; the oscillating voltage source is a controlled voltage source, and its control signal is obtained by feedback from the impedance circuit, representing the oscillating voltage component during system oscillation; since the impedance of the VSC-HVDC system is equivalent to four RLC branches in the dq synchronous rotating coordinate system and cannot be directly connected to the wind turbine and the power frequency voltage source in the abc three-phase stationary coordinate system, the output dynamics of the VSC-HVDC system are replaced by an oscillating voltage source and connected to the main circuit to form a virtual connection between the impedance of the VSC-HVDC system, the wind turbine, and the power frequency voltage source.

[0145] As Figure 5 shown, the impedance circuit represents the impedance characteristics of the VSC-HVDC system in a selected frequency band, which is composed of four independent sub-circuits dd, dq, qd, and qq, respectively representing the impedance Z dd , Z dq , Z qd and Z qq, each sub - circuit is composed of an oscillating current source and an RLC branch in series. Among them, the oscillating current source is a controlled current source, and its control signal is obtained by collecting from the main circuit, representing the oscillating current component during system oscillation. The voltage - current relationship in the impedance circuit follows the following formula (9); the input of sub - circuit dd is the d - axis oscillating current i rd , and the output is the d - axis oscillating voltage component u rdd ; the input of sub - circuit dq is the d - axis oscillating current i rd , and the output is the q - axis oscillating voltage component u rdq ; the input of sub - circuit qd is the q - axis oscillating current i rq , and the output is the d - axis oscillating voltage component u rqd ; the input of sub - circuit qq is the q - axis oscillating current i rq , and the output is the q - axis oscillating voltage component u rqq ;

[0146] (9)

[0147] The signal processing module is responsible for connecting the main circuit and the impedance circuit, and is composed of a voltage signal processing unit and a current signal processing unit; the purpose of current signal processing is to convert the abc three - phase alternating current collected in the main circuit into the dq - axis oscillating current applicable to the oscillating circuit, and its principle is as Figure 6 shown; measure the abc three - phase alternating current at the AC port of the wind turbine i abc , and convert it into the dq - axis current through dq transformation i dq , where the phase angle of the dq transformation takes the phase angle of the power - frequency voltage source. Use the obtained dq - axis current i dq minus the dq - axis current during the steady - state operation of the system i dq0 , then the dq - axis oscillating current i rdq is obtained. If there is no oscillation in the system, the dq - axis oscillating current is 0;

[0148] The purpose of voltage signal processing is to convert the oscillating voltage collected in the oscillating circuit into the abc three - phase oscillating voltage applicable to the main circuit, and its principle is as Figure 7 shown; measure the voltages in the four sub - circuits in the oscillating circuit respectively to obtain u rdd , urdq , u rqd and u rqq ; Add u rdd and u rdq to obtain the d-axis oscillation voltage u rd ; Add u rqd and u rqq to obtain the q-axis oscillation voltage u rq ; Perform a dq inverse transformation on u rd and u rq , and take the phase angle of the power frequency voltage source for the inverse transformation phase angle to obtain the abc three-phase oscillation voltage u rabc ;

[0149] S5. Reproduce the broadband impedance dynamic characteristics of the physical wind turbine grid-connected system through the broadband oscillation condition simulation circuit, and detect the grid connection stability of the physical wind turbine; The specific steps of step S5 are as follows:

[0150] S51. Based on the established broadband oscillation condition simulation circuit, reproduce the oscillation conditions and change the control parameters of the physical wind turbine;

[0151] S52. Identify whether the oscillation characteristics of the wind turbine are consistent with the expected characteristics;

[0152] If so, go to step S53;

[0153] If not, go to step S56;

[0154] S53. Judge whether each frequency band has been tested;

[0155] If so, go to step S55;

[0156] If not, go to step S54;

[0157] S54. Select one of the frequency bands divided from the full-band dq impedance characteristic curve as the test frequency band and return to step S32;

[0158] S55. Determine that the physical wind turbine meets the requirements, the test passes, and end;

[0159] S56. Determine that the physical wind turbine test fails;

[0160] It should be noted that the working principle of the broadband oscillation condition simulation circuit is as follows: At a certain moment, the control parameters of the wind turbine are changed to cause oscillation in the system, and then the system voltage and current will exhibit corresponding oscillation characteristics; in the main circuit, the abc three-phase currents at the AC side port of the wind turbine are continuously measured i abc , which are converted into oscillation current signals by the current signal processing unit and input into the impedance circuit. The four controlled current sources in the impedance circuit output corresponding dq-axis oscillation currents i rdq ; the dq-axis oscillation currents flow through the RLC branch to generate dq-axis oscillation voltages u rdq , and the oscillation voltages are continuously acquired, converted into oscillation voltage signals by the voltage signal processing module, and fed back to the main circuit to control the oscillation voltage source to generate corresponding abc three-phase oscillation voltages u rabc ; the three-phase oscillation voltages are loaded at the AC side port of the wind turbine, which will in turn excite corresponding oscillation currents; by sequentially replacing the impedance circuits in different frequency bands, the oscillation conditions of the wind turbine in the full frequency band can be obtained; through this interaction method, the broadband oscillation condition simulation circuit can finally simulate the broadband oscillation condition of the grid-connected system

[0161] If, after the tested wind turbine is tested by the broadband oscillation condition simulation circuit, it is found that its oscillation characteristics are all consistent with the expected oscillation characteristics, it indicates that the wind turbine meets the expected manufacturing target and passes the test; if the oscillation characteristics of the wind turbine in a certain frequency band do not match the expected oscillation characteristics, the wind turbine fails the test

[0162] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention

[0163] As Figure 2 shown, the following is an embodiment of the grid-connected broadband oscillation power grid simulation system for a wind turbine provided by the embodiments of the present disclosure. This system and the grid-connected broadband oscillation power grid simulation method for a wind turbine in the above embodiments belong to the same inventive concept. For the details not described in detail in the embodiment of the grid-connected broadband oscillation power grid simulation system for a wind turbine, reference can be made to the embodiment of the grid-connected broadband oscillation power grid simulation method for a wind turbine

[0164] The system includes:

[0165] A full-frequency band impedance characteristic curve acquisition unit, which is used to perform frequency sweeping on the grid side part of the physical wind turbine grid-connected system to obtain the full-frequency band dq impedance characteristic curve of the grid side part of the physical wind turbine grid-connected system

[0166] The impedance characteristic curve segmentation unit is used to segment the full-band dq impedance characteristic curve according to frequency, ensuring the maximum bandwidth for each frequency band when determining the order required for fitting with a rational function, and the minimum order required for fitting with a rational function when determining the bandwidth for each frequency band;

[0167] The RLC branch equivalent unit is used to perform rational function fitting on the dq impedance characteristic curve of each frequency band using the least squares method, and equivalent the grid-side part of the physical wind turbine grid-connected system to an RLC branch according to the rational function expression obtained by fitting;

[0168] The analog circuit construction unit is used to construct an impedance circuit characterized by a series connection of an oscillating current source and an equivalent RLC branch for each frequency band, construct a main circuit characterized by a series connection of a power frequency voltage source and an oscillating voltage source, and construct a signal processing module for virtually connecting the main circuit and the impedance circuit to complete the construction of the wide-frequency oscillation condition analog circuit;

[0169] The oscillation condition reproduction unit is used to reproduce the wide-frequency impedance dynamic characteristics of the physical wind turbine grid-connected system through the wide-frequency oscillation condition analog circuit, and detect the grid connection stability of the physical wind turbine.

[0170] In this embodiment, through the full-band impedance characteristic curve acquisition unit, the impedance characteristic curve segmentation unit, the RLC branch equivalent unit, the analog circuit construction unit, and the oscillation condition reproduction unit, steps such as the acquisition, segmentation processing, RLC branch equivalence, analog circuit construction, and oscillation condition reproduction of the full-band impedance characteristic curve can be automatically completed, improving the test efficiency and accuracy.

[0171] The wind turbine grid-connected wide-frequency oscillation power grid simulation method provided by the embodiment of the present application can be applied to an electronic device. Those skilled in the art can understand that the structure of the electronic device involved in the embodiment of the present invention does not constitute a limitation on the electronic device. The electronic device may include more or fewer components than shown in the figure, or combine some components, or have different component arrangements. In the embodiment of the present invention, the electronic device includes, but is not limited to, a laptop computer, a desktop computer, a workbench, a personal digital assistant, a server, a blade server, a mainframe computer, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the embodiments of the present application described herein and / or claimed.

[0172] An electronic device may include a processor, an external memory interface, an internal memory, a Universal Serial Bus (USB) interface, a charging management module, a power management module, a battery, a wireless communication module, an audio module, a speaker, a microphone, a sensor module, buttons, a camera, a display screen, and a Subscriber Identity Module (SIM) card interface, etc.

[0173] It can be understood that the structure illustrated in the embodiments of this application does not constitute a specific limitation on the electronic device. In other embodiments of this application, the electronic device may include more or fewer components than those illustrated, or combine certain components, or split certain components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0174] The processor may include one or more processing units. For example, the processor may include a Central Processing Unit (CPU), etc., an Application Processor (AP), a modem processor, a Graphics Processing Unit (GPU), an Image Signal Processor (ISP), a controller, a memory, a video codec, a Digital Signal Processor (DSP), a baseband processor, and / or a Neural-Network Processing Unit (NPU), etc. Among them, different processing units may be independent devices or integrated in one or more processors.

[0175] Among them, the processor may be the nerve center and command center of the electronic device. The controller may generate operation control signals according to the instruction operation code and timing signals to complete the control of fetching and executing instructions.

[0176] A memory may also be provided in the processor for storing instructions and data. In some embodiments, the memory in the processor is a cache memory. This memory may save the instructions or data that the processor has just used or recycled. If the processor needs to use the instruction or data again, it can directly call it from this memory. This avoids repeated accesses, reduces the waiting time of the processor, and thus improves the system efficiency.

[0177] The above electronic device implements the technical solution of the grid simulation method for wide - frequency oscillation of wind turbine grid connection in the present application, which equivalently represents the complex grid - connection system impedance as a low - order RLC circuit within the allowable accuracy range, and then simulates the wide - frequency oscillation condition and is used in the grid - connection stability test link of new - energy units such as wind turbines, achieving the beneficial effect of avoiding the problems that the simulation accuracy of the grid simulator based on the power - electronic converter topology is limited by the switching frequency and control accuracy, and the simulation accuracy of the grid simulator based on hardware - in - the - loop simulation is limited by the error between the theoretical model and the real system.

[0178] In the storage medium provided by the present application, there is a program product capable of implementing the grid simulation method for wide - frequency oscillation of wind turbine grid connection.

[0179] The grid simulation method for wide - frequency oscillation of wind turbine grid connection includes: sweeping the frequency of the grid - side part of the physical wind turbine grid - connection system to obtain the full - frequency - band dq impedance characteristic curve of the grid - side part of the physical wind turbine grid - connection system; segmenting the full - frequency - band dq impedance characteristic curve according to frequency to ensure that the bandwidth of each frequency band is the largest when determining the order required for fitting with rational functions, and the order required for fitting with rational functions is the smallest when determining the bandwidth of each frequency band; using the least - squares method to perform rational - function fitting on the dq impedance characteristic curve of each frequency band, and equivalently representing the grid - side part of the physical wind turbine grid - connection system as an RLC branch according to the fitted rational - function expression; constructing an impedance circuit characterized by a series connection of an oscillating current source and the equivalent RLC branch for each frequency band, constructing a main circuit characterized by a series connection of a power - frequency voltage source and an oscillating voltage source, and constructing a signal - processing module for virtually connecting the main circuit and the impedance circuit to complete the construction of the wide - frequency oscillation condition simulation circuit; reproducing the wide - frequency impedance dynamic characteristics of the physical wind turbine grid - connection system through the wide - frequency oscillation condition simulation circuit and detecting the grid - connection stability of the physical wind turbine.

[0180] In some possible implementation manners, the grid simulation method for wide - frequency oscillation of wind turbine grid connection of the present disclosure can be implemented in the form of a program product, which includes program code. When the program product runs on a terminal device, the program code is used to cause the terminal device to execute the steps according to various exemplary embodiments of the present disclosure described in the "Exemplary Method" section of this specification.

[0181] The storage medium of the present disclosure may adopt any combination of one or more readable media. The readable media may be a readable signal medium or a readable storage medium. The readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples (non-exhaustive list) of the readable storage medium include: an electrical connection having one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0182] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for simulating a grid-connected wide-frequency oscillation power grid of a wind turbine, characterized in that It includes the following steps: S1. Perform frequency sweeping on the grid-side part of the physical wind turbine grid-connected system to obtain the full-frequency dq impedance characteristic curve of the grid-side part of the physical wind turbine grid-connected system; S2. Process the full-frequency dq impedance characteristic curve by frequency band segmentation to ensure that the bandwidth of each frequency band is the largest when determining the order required for fitting with a rational function, and the order required for fitting with a rational function is the smallest when determining the bandwidth of each frequency band. The specific steps of step S2 are as follows: S21. Initially divide the full-frequency dq impedance characteristic curve into several frequency bands; S22. Fit each frequency band with a rational function to determine the order required for fitting; S23. Judge whether the order required for fitting in each frequency band is less than the set order threshold; If yes, go to step S25; If no, go to step S24; S24. Re-segment the full-frequency dq impedance characteristic curve in the way of reducing the frequency bandwidth, and return to step S22; S25. Judge whether the frequency bands can be merged under the condition of fixing the order required for fitting in each current frequency band; If yes, go to step S26; If no, determine the division of each frequency band and go to step S3; S26. Merge the frequency bands to obtain the final frequency band division; S3. Use the least squares method to perform rational function fitting on the dq impedance characteristic curve of each frequency band, and equivalent the grid-side part of the physical wind turbine grid-connected system to an RLC branch according to the fitted rational function expression; S4. Construct an impedance circuit characterized by a series connection of an oscillating current source and an equivalent RLC branch for each frequency band, construct a main circuit characterized by a series connection of a power frequency voltage source and an oscillating voltage source, and construct a signal processing module for virtual connection between the main circuit and the impedance circuit to complete the construction of a broadband oscillation condition simulation circuit; S5. Reproduce the broadband impedance dynamic characteristics of the physical wind turbine grid-connected system through the broadband oscillation condition simulation circuit, and detect the grid connection stability of the physical wind turbine.

2. The grid simulation method for wide-frequency oscillation of a wind turbine generator set connected to the grid according to claim 1, wherein The specific steps of step S1 are as follows: S11. Determine the number of experiments N, N≥2; S12. Inject harmonic disturbance current into the physical wind turbine grid-connected system in each experiment; S13. Change the frequency of the injected harmonic disturbance current according to the set amplitude, and obtain the full-frequency dq impedance characteristic curve of the grid-side part of the physical wind turbine grid-connected system output according to the sending mode through measurement and calculation; the sending modes include flexible DC transmission sending, power frequency AC sending, diode uncontrolled rectification sending, and frequency division transmission sending; S14. Compare the full-frequency dq impedance characteristic curves obtained from N experiments, and judge that the difference between the full-frequency dq impedance characteristic curves is less than the set amplitude; If yes, the test result is credible, and go to step S2; If no, the test result is not credible, and return to step S12.

3. The method for simulating a grid with wideband oscillations during grid connection of a wind turbine generator set according to claim 2, wherein The specific steps of step S3 are as follows: S31. Select one of the frequency bands divided from the full-frequency dq impedance characteristic curve as the test frequency band; S32. Use the least squares method to perform rational function fitting on the dq impedance characteristic curve segment corresponding to the test frequency band to ensure the fitting accuracy and perform order reduction to obtain a 2×2 order dq impedance rational function matrix; S33. Represent each impedance rational function in the 2×2 dq rational function matrix as a real pole part, a conjugate complex pole part, a constant term, and a first-order term part; S34. Perform RLC branch equivalent on the 2×2 dq impedance rational function matrix to obtain a real pole term branch, a conjugate complex pole term branch, a constant term, and a first-order term branch. Then, combined with the series or parallel implementation form, obtain four equivalent RLC branches in the determined implementation form.

4. The method for simulating a grid with wide-frequency oscillations during grid connection of a wind turbine unit according to claim 3, wherein The specific steps of step S34 are as follows: S341. Determine the implementation form; If it is the series implementation form, go to step S342; If it is the parallel implementation form, go to step S344; S342. Connect the real pole term branch, the conjugate complex pole term branch, and the constant term and first-order term branches in series; S343. Use a parallel combination of a resistor and a capacitor to represent the real pole term branch, use a series combination of a resistor and an inductor followed by a parallel combination of a resistor and a capacitor to represent the conjugate complex pole term branch, and use a series combination of a resistor and an inductor to represent the constant term and first-order term branches, obtaining four equivalent RLC branches in the series implementation form; S344. Connect the real pole term branch, the conjugate complex pole term branch, and the constant term and first-order term branches in parallel; S345. Use a series combination of a resistor and an inductor to represent the real pole term branch, use a parallel combination of a resistor and a capacitor followed by a series combination of an inductor and a resistor to represent the conjugate complex pole term branch, and use a parallel combination of a resistor and a capacitor to represent the constant term and first-order term branches, obtaining four equivalent RLC branches in the parallel implementation form.

5. The grid-connected wide-frequency oscillation power grid simulation method for a wind turbine generator set according to claim 3, characterized in that, The specific steps of step S4 are as follows: S41. Connect a controlled oscillating current source in series with each of the four equivalent RLC branches to obtain four sub-circuits as impedance circuits; S42. Connect a power frequency voltage source and a controlled oscillating voltage source in series to form a main circuit, leaving an external port for connecting the physical wind turbine to be measured, and set the voltage value of the power frequency voltage source to the grid-side three-phase AC voltage under the stable operation condition of the physical wind turbine grid-connected system; S43. Construct a signal processing module including a voltage signal processing unit and a current signal processing unit; S44. Convert the current control signal collected from the main circuit into an oscillating current signal through the current signal processing unit to control the controlled oscillating current sources in each sub-circuit of the impedance circuit to output dq-axis oscillating currents; S45. Convert the dq-axis oscillating voltages generated by each sub-circuit according to the dq-axis oscillating currents into oscillating voltage signals through the voltage signal processing unit and feedback them to the main circuit to control the controlled oscillating voltage source to output three-phase oscillating voltages, and load them at the AC side port of the physical wind turbine to generate oscillating currents, completing the construction of the broadband oscillation condition simulation circuit.

6. The grid connection broadband oscillation power grid simulation method for a wind turbine unit according to claim 5, characterized in that, The specific steps of step S5 are as follows: S51. Based on the constructed broadband oscillation condition simulation circuit, reproduce the oscillation condition and change the control parameters of the physical wind turbine; S52. Identify whether the oscillation characteristics of the wind turbine are consistent with the expected characteristics; If so, go to step S53; If not, go to step S56; S53. Determine whether each frequency band has been tested; If so, go to step S55; If not, proceed to step S54; S54. Select one of the frequency bands divided from the full-band dq impedance characteristic curve as the test frequency band, and return to step S32; S55. Determine that the physical wind turbine meets the requirements and the test passes, and end; S56. Determine that the test of the physical wind turbine fails.

7. A wind turbine grid-connected broadband oscillation power grid simulation system for implementing the wind turbine grid-connected broadband oscillation power grid simulation method according to any one of claims 1-6, characterized in that, Including: Full-band impedance characteristic curve acquisition unit, which is used to perform frequency sweeping on the grid-side part of the physical wind turbine grid-connected system to obtain the full-band dq impedance characteristic curve of the grid-side part of the physical wind turbine grid-connected system; Impedance characteristic curve segmentation unit, which is used to segment the full-band dq impedance characteristic curve according to frequency to ensure that the bandwidth of each frequency band is the largest when determining the order required for fitting with a rational function, and the order required for fitting with a rational function is the smallest when determining the bandwidth of each frequency band; RLC branch equivalent unit, which is used to perform rational function fitting on the dq impedance characteristic curve of each frequency band using the least squares method, and equivalent the grid-side part of the physical wind turbine grid-connected system to an RLC branch according to the fitted rational function expression; Analog circuit construction unit, which is used to construct an impedance circuit characterized by a series connection of an oscillating current source and an equivalent RLC branch for each frequency band, construct a main circuit characterized by a series connection of a power frequency voltage source and an oscillating voltage source, and construct a signal processing module for virtual connection of the main circuit and the impedance circuit to complete the construction of the wide-frequency oscillation condition simulation circuit; Oscillation condition reproduction unit, which is used to reproduce the wide-frequency impedance dynamic characteristics of the physical wind turbine grid-connected system through the wide-frequency oscillation condition simulation circuit and detect the grid connection stability of the physical wind turbine.

8. An electronic device, characterized in that, It includes a memory, a processor, and a computer program stored on the memory and executable on the processor. The characteristic is that when the processor executes the program, it implements the steps of the wind turbine grid-connected wide-frequency oscillation power grid simulation method according to any one of claims 1 to 6.

9. A storage medium, on which a computer program is stored, characterized in that, When the computer program is executed by the processor, it implements the steps of the wind turbine grid-connected wide-frequency oscillation power grid simulation method according to any one of claims 1 to 6.

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