A high-frequency resonance dynamic suppression method and system for a direct-drive wind turbine grid-connected inverter

Abstract

The present application relates to the technical field of resonance suppression, and particularly relates to a direct-drive wind turbine grid-connected inverter high-frequency resonance dynamic suppression method and system, comprising the following steps: obtaining a preliminary damping value according to extracted high-frequency resonance natural frequency oscillation distribution data; dynamically compensating and adjusting an active resonance suppression time delay factor based on the preliminary damping value and a power grid voltage fluctuation influence factor, and obtaining a high-frequency resonance characteristic value; calculating a frequency drift offset amount according to the high-frequency resonance characteristic value and an upper limit value of a bandwidth of a grid-connected inverter controller; when the frequency drift offset amount exceeds a preset drift threshold range, optimizing an active damping gain parameter with the optimization target of minimizing a resonance peak value and maximizing a dynamic response margin, and outputting a high-frequency resonance active suppression parameter optimization set, thereby completing high-frequency resonance active suppression of the direct-drive wind turbine grid-connected inverter system. The present application realizes effective high-frequency resonance suppression of the direct-drive wind turbine grid-connected inverter system by optimizing the active damping gain parameter, thereby guaranteeing stable operation of the system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of resonance suppression, and particularly relates to a high-frequency resonance dynamic suppression method and system for a direct-drive wind turbine grid-connected inverter. BACKGROUND

[0002] With the rapid development of renewable energy generation technology, direct-drive permanent magnet synchronous wind power generation systems have been widely used in the field of wind power grid connection due to their simple structure, high efficiency, low maintenance cost and other advantages. However, the direct-drive wind turbine grid-connected inverter system faces the problem of high-frequency resonance in actual application, which has a significant impact on the stability of the system. With large-scale grid connection of wind power, high-frequency resonance frequently occurs in the direct-drive wind turbine grid-connected inverter system due to the rapid switching action of power electronic devices and the complex interaction between the grid and the inverter. This high-frequency resonance not only causes serious distortion of the grid-side current, which in turn affects the power quality, but also distorts the inverter output voltage waveform, increases the loss and fault risk of the equipment. Especially in the case of complex grid conditions or severe load changes, the problem of high-frequency resonance is more prominent, which seriously threatens the safe and stable operation of the grid.

[0003] At present, although some suppression methods have been proposed for the problem of high-frequency resonance in the direct-drive wind turbine grid-connected inverter system, these methods still have many shortcomings in actual application. On the one hand, the natural frequency of high-frequency resonance is influenced by the grid impedance, filter parameters and inverter control characteristics, showing complex distribution characteristics. Traditional resonance suppression methods are usually based on fixed filter parameter design, which is difficult to adapt to the dynamic changes of grid impedance, resulting in poor resonance suppression effect. Especially in weak grid conditions, the wide range of changes in grid impedance will further exacerbate the drift of resonance frequency, making it impossible for fixed-parameter active damping control to effectively cover the resonance frequency band, thereby causing system oscillation or harmonic amplification problems. On the other hand, existing active damping strategies have insufficient dynamic response margin. Since the grid-connected inverter needs to meet the dual requirements of power smooth output and high-frequency resonance suppression, the selection of the bandwidth and damping gain of the controller often needs to be considered. If the damping gain is set too high, although it can enhance the resonance suppression effect to some extent, it may slow down the dynamic response of the system and affect the rapidity of power regulation. If the damping gain is set too low, it cannot effectively suppress resonance, causing serious distortion of the grid-side current. In addition, the fluctuation of grid voltage will further affect the stability of resonance suppression, making it difficult for traditional control methods to maintain good performance under complex conditions.

[0004] Therefore, the prior art has many defects in solving the high-frequency resonance problem of the direct-drive wind turbine grid-connected inverter, and it is urgent to develop a more efficient and reliable high-frequency resonance active suppression method, which is of great significance to improve the stability and reliability of the direct-drive wind turbine grid-connected inverter system and ensure the reliable operation of the direct-drive wind turbine grid-connected system under high-frequency resonance conditions. SUMMARY

[0005] To solve the above technical problems, the present application provides a high-frequency resonance dynamic suppression method and system for a direct-drive wind turbine grid-connected inverter.

[0006] In a first aspect, the present application provides a high-frequency resonance dynamic suppression method for a direct-drive wind turbine grid-connected inverter, comprising the following steps:

[0007] Extracting high-frequency resonance natural frequency oscillation distribution data from the collected grid-side current data and grid-connected inverter output voltage waveform data;

[0008] Determining an active resonance suppression time delay factor based on the high-frequency resonance natural frequency oscillation distribution data, and obtaining a preliminary damping value under the effect of an equivalent series resistance according to the active resonance suppression time delay factor and a grid-connected power smoothing constraint condition;

[0009] Superimposing the preliminary damping value and a grid voltage fluctuation influence factor obtained in advance to obtain a superposition result, and dynamically compensating and adjusting the active resonance suppression time delay factor according to the superposition result to obtain a high-frequency resonance characteristic value;

[0010] Calculating a frequency drift offset based on the difference between the high-frequency resonance characteristic value and an upper limit value of the bandwidth of the grid-connected inverter controller;

[0011] When the frequency drift offset exceeds a preset drift threshold range, optimizing the active damping gain parameter to minimize the resonance peak value and maximize the dynamic response margin as the optimization objective, and outputting a high-frequency resonance active suppression parameter optimization set;

[0012] Using the high-frequency resonance active suppression parameter optimization set to perform high-frequency resonance active suppression on the direct-drive wind turbine grid-connected inverter system.

[0013] In further embodiments, the step of extracting high-frequency resonance natural frequency oscillation distribution data from the collected grid-side current data and grid-connected inverter output voltage waveform data comprises:

[0014] Collecting grid-side current data and grid-connected inverter output voltage waveform data, and removing high-frequency noise from the grid-side current data using a sliding window mean filtering algorithm to obtain grid-side denoised current data;

[0015] The grid-connected inverter output voltage waveform data is subjected to amplitude normalization processing to obtain standardized voltage waveform data;

[0016] The grid-side denoised current data is subjected to frequency spectrum analysis by using fast Fourier transform to obtain a frequency domain amplitude spectrum, and based on the frequency component amplitudes in the frequency domain amplitude spectrum, current distortion frequency component distribution data of each harmonic component and a high-frequency band are extracted;

[0017] The standardized voltage waveform data is subjected to waveform analysis to extract voltage oscillation characteristic parameters;

[0018] When high-frequency resonance is determined to occur, the high-frequency resonance natural frequency oscillation distribution data is determined according to the current distortion frequency component distribution data and the voltage oscillation characteristic parameters in the high-frequency resonance coinciding frequency band.

[0019] In further embodiments, the step of determining the active resonance suppression time delay factor based on the high-frequency resonance natural frequency oscillation distribution data comprises:

[0020] The filter measured reactance parameters in the direct-drive wind turbine grid-connected inverter system are obtained, and the main resonance frequency point is determined according to the high-frequency resonance natural frequency oscillation distribution data;

[0021] The equivalent reactance distribution data of the filter at the main resonance frequency point is extracted according to the filter measured reactance parameters;

[0022] Based on the equivalent reactance distribution data, the least square method is used to fit the reactance-frequency relationship to generate a reactance-frequency characteristic model;

[0023] According to the impedance change rate of the reactance-frequency characteristic model, the impedance mutation degree of the high-frequency resonance frequency band is determined, and according to the impedance mutation degree and a preset mutation threshold, the impedance mutation frequency band range is determined;

[0024] Within the impedance mutation frequency band range, the active damping gain initial value under the phase compensation angle constraint is calculated using the main resonance frequency point;

[0025] It is determined whether the active damping gain initial value meets a preset phase margin stability condition, and if so, the active resonance suppression time delay factor is obtained based on the active damping gain initial value using a phase compensation relationship.

[0026] In further embodiments, the step of obtaining the preliminary damping value under the effect of the equivalent series resistance based on the active resonance suppression time delay factor and the grid-connected power smoothing constraint condition comprises:

[0027] Obtaining a grid-connected power smoothing constraint condition of a direct-drive wind turbine grid-connected inverter system, quantifying the grid-connected power smoothing constraint condition into a frequency-domain-time-domain joint indicator, and generating a grid-connected power smoothing constraint parameter set;

[0028] Obtaining an equivalent series resistance according to the active resonance suppression delay factor and the main resonance frequency point;

[0029] Inputting the equivalent series resistance into the closed-loop transfer function of the direct-drive wind turbine grid-connected inverter system to calculate the corresponding grid-side current harmonic distortion rate and active power fluctuation rate;

[0030] comparing the grid-side current harmonic distortion rate and the active power fluctuation rate with the grid-connected power smoothing constraint parameter set, and extracting an active damping gain value corresponding to a current equivalent series resistance when both the grid-side current harmonic distortion rate and the active power fluctuation rate satisfy the grid-connected power smoothing constraint parameter set;

[0031] The active damping gain value corresponding to the current equivalent series resistance is used as the preliminary damping value under the equivalent series resistance effect.

[0032] In a further embodiment, the grid-connected power smoothing constraint condition includes at least an active power fluctuation rate constraint condition and a total harmonic distortion rate constraint condition.

[0033] In a further embodiment, the step of dynamically compensating and adjusting the active resonance suppression delay factor according to the superposition result to obtain a high-frequency resonance characteristic value includes:

[0034] According to the superposition result, adjusting the active resonance suppression delay factor through a linear compensation relationship to obtain a corrected value of the active resonance suppression delay factor;

[0035] Using the active resonance suppression delay factor correction value to adjust the delay compensation amount of the pulse modulation signal in the grid-connected inverter controller in real time;

[0036] Delay compensation closed-loop control is performed according to the delay compensation amount, grid-side current time series data after closed-loop control is obtained, and spectrum analysis is performed on the grid-side current time series data to extract high-frequency resonance characteristic values.

[0037] In a further embodiment, the high-frequency resonance characteristic value includes the resonance frequency point, resonance amplitude and phase mutation interval obtained by dynamic compensation after superimposing the grid fluctuation.

[0038] In a further embodiment, the step of optimizing the active damping gain parameters with minimizing the resonance peak and maximizing the dynamic response margin as the optimization goal and outputting the optimized set of high-frequency resonance active suppression parameters includes:

[0039] define the active damping gain parameter as a decision variable, and set the optimization range of the active damping gain parameter;

[0040] In the optimization range of the active damping gain parameter, a plurality of particles are randomly generated to form an initial particle group, with the optimization objectives of minimizing the resonance peak value and maximizing the dynamic response margin;

[0041] The active damping gain parameter of each particle is input into the grid-connected inverter controller, and the resonance peak value is obtained through closed-loop simulation, and the phase margin and amplitude margin under the current active damping gain parameter are calculated to obtain the dynamic response margin;

[0042] According to the resonance peak value and the dynamic response margin, the current fitness value of each particle is calculated, and the individual extreme position is updated according to the current fitness value of each particle;

[0043] The global optimal solution is found among the individual extreme positions of all particles, the global extreme position is updated through the global optimal solution, and the speed and position of each particle are updated according to the updated individual extreme position and global extreme position;

[0044] Repeat the above steps until the fitness value converges, output the active damping gain parameter combination corresponding to the global optimal extreme position, and form the high-frequency resonance active suppression parameter optimization set.

[0045] In further embodiments, the fitness function of each particle is defined as the weighted sum of the inverse of the resonance peak value and the dynamic response margin.

[0046] In a second aspect, the present application provides a direct-drive wind turbine grid-connected inverter high-frequency resonance dynamic suppression system, which comprises:

[0047] A data acquisition module is configured to extract high-frequency resonance natural frequency oscillation distribution data from the collected grid-side current data and grid-connected inverter output voltage waveform data;

[0048] A damping analysis module is configured to determine an active resonance suppression time delay factor based on the high-frequency resonance natural frequency oscillation distribution data, and to obtain a preliminary damping value under the effect of an equivalent series resistance according to the active resonance suppression time delay factor and a grid-connected power smoothing constraint condition;

[0049] A dynamic compensation module is configured to superimpose the preliminary damping value and a pre-acquired grid voltage fluctuation influence factor to obtain a superimposition result, and to dynamically compensate and adjust the active resonance suppression time delay factor according to the superimposition result to obtain a high-frequency resonance characteristic value;

[0050] A drift analysis module is configured to calculate a frequency drift offset based on the difference between the high-frequency resonance characteristic value and an upper limit value of the bandwidth of the grid-connected inverter controller;

[0051] a parameter optimization module, configured to, when the frequency drift offset is out of the preset drift threshold range, optimize the active damping gain parameter with the optimization target of minimizing the resonance peak value and maximizing the dynamic response margin, and output an optimized set of high-frequency resonance active suppression parameters;

[0052] a resonance suppression module, configured to perform high-frequency resonance active suppression on the direct-drive wind turbine grid-connected inverter system by using the optimized set of high-frequency resonance active suppression parameters.

[0053] The present application provides a direct-drive wind turbine grid-connected inverter high-frequency resonance dynamic suppression method and system. The method extracts high-frequency resonance natural frequency oscillation distribution data from the collected grid-side current data and grid-connected inverter output voltage waveform data. Based on the high-frequency resonance natural frequency oscillation distribution data, the active resonance suppression time delay factor is determined, and the preliminary damping value under the equivalent series resistance effect is obtained according to the active resonance suppression time delay factor and the grid-connected power smoothing constraint condition. The preliminary damping value is superimposed with the pre-obtained grid voltage fluctuation influence factor to obtain a superposition result, and the active resonance suppression time delay factor is dynamically compensated and adjusted according to the superposition result to obtain the high-frequency resonance characteristic value. The frequency drift offset is calculated according to the difference between the high-frequency resonance characteristic value and the upper limit value of the bandwidth of the grid-connected inverter controller. When the frequency drift offset is out of the preset drift threshold range, the active damping gain parameter is optimized with the optimization target of minimizing the resonance peak value and maximizing the dynamic response margin, and an optimized set of high-frequency resonance active suppression parameters is output. The high-frequency resonance active suppression parameter optimization set is used to perform high-frequency resonance active suppression on the direct-drive wind turbine grid-connected inverter system. Compared with the prior art, the method optimizes the active damping gain parameter, realizes effective suppression of high-frequency resonance of the direct-drive wind turbine grid-connected inverter system under complex working conditions, improves the overall operation performance of the system, and ensures safe and stable operation of the system. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 is a direct-drive wind turbine grid-connected inverter high-frequency resonance dynamic suppression method flowchart provided by the embodiment of the present application;

[0055] Figure 2 is a direct-drive wind turbine grid-connected inverter high-frequency resonance dynamic suppression system block diagram provided by the embodiment of the present application.

[0056] Mark explanation: 101, data acquisition module; 102, damping analysis module; 103, dynamic compensation module; 104, drift analysis module; 105, parameter optimization module; 106, resonance suppression module. DETAILED DESCRIPTION

[0057] The embodiments of the present application will be described in detail below with reference to the drawings, the embodiments are given only for illustrative purposes and should not be construed as limiting the present application, the accompanying drawings are only for reference and illustration and do not constitute a limitation on the scope of patent protection of the present application, because many changes can be made to the present application without departing from the spirit and scope of the present application.

[0058] Reference Figure 1 The embodiments of the present application provide a high-frequency resonance dynamic suppression method for a direct-drive wind turbine grid-connected inverter, as shown in Figure 1 The method comprises the following steps:

[0059] S1. Extract high-frequency resonance natural frequency oscillation distribution data from the collected grid-side current data and grid-connected inverter output voltage waveform data.

[0060] In some embodiments, the step of extracting high-frequency resonance natural frequency oscillation distribution data from the collected grid-side current data and grid-connected inverter output voltage waveform data comprises:

[0061] Collecting grid-side current data and grid-connected inverter output voltage waveform data, and using a sliding window mean filtering algorithm to remove high-frequency noise from the grid-side current data to obtain grid-side denoised current data;

[0062] Performing amplitude normalization processing on the grid-connected inverter output voltage waveform data to obtain standardized voltage waveform data;

[0063] Performing frequency spectrum analysis on the grid-side denoised current data using fast Fourier transform to obtain frequency domain amplitude spectrum, and based on the frequency component amplitudes in the frequency domain amplitude spectrum, extracting current distortion frequency component distribution data of each harmonic component and high-frequency band;

[0064] Performing waveform analysis on the standardized voltage waveform data to extract voltage oscillation characteristic parameters;

[0065] When high-frequency resonance occurs, determining high-frequency resonance natural frequency oscillation distribution data according to the current distortion frequency component distribution data and voltage oscillation characteristic parameters in the high-frequency resonance coincident frequency band.

[0066] Specifically, the embodiment collects grid-side current data from a grid connection point (i.e. an output end of a grid-connected inverter and an interface with a grid) of a direct-drive wind turbine grid-connected inverter system, removes high-frequency noise from the grid-side current data based on a sliding window mean filtering algorithm, for example, removes high-frequency switching noise above 10 kHz, retains grid-side denoised current data of an effective frequency band signal, and performs fast Fourier transform on the grid-side denoised current data to calculate a frequency domain amplitude spectrum. Based on a percentage of amplitudes of frequency components in the frequency domain amplitude spectrum relative to an amplitude of a fundamental wave, the embodiment extracts harmonic components (such as 5th, 7th and 11th) and high-frequency band distortion frequency components to generate current distortion frequency component distribution data. The current distortion frequency component distribution data can include, but is not limited to, frequency points, corresponding amplitude percentage and phase angle data,

[0067] Meanwhile, the embodiment collects grid-connected inverter output voltage waveform data from an output end of a direct-current alternating-current conversion unit of the grid-connected inverter, and performs amplitude normalization processing on the grid-connected inverter output voltage waveform data to eliminate direct current bias and generate standardized voltage waveform data. For the standardized voltage waveform data, the embodiment calculates a voltage waveform oscillation frequency using a zero-crossing point detection algorithm, and extracts an oscillation amplitude of the voltage waveform and an oscillation decay rate (adjacent peak value decay ratio) of adjacent peak values based on a peak value detection algorithm to generate voltage oscillation characteristic parameters. The voltage oscillation characteristic parameters can include an oscillation frequency, an amplitude, a decay rate and a time domain waveform distortion rate. If there is a component with a frequency greater than 1 kHz and an amplitude exceeding a preset amplitude threshold (such as 3% of the amplitude of the fundamental wave) in the current distortion frequency component distribution data, it is marked as a high-frequency distortion frequency band. The embodiment combines the oscillation frequency in the voltage oscillation characteristic parameters to determine whether the high-frequency distortion frequency band coincides with the voltage oscillation frequency. If the oscillation decay rate of the coinciding frequency band is less than a preset oscillation decay threshold (i.e. the oscillation continues without decay), it is determined that high-frequency resonance occurs, and a high-frequency resonance occurrence flag signal and a corresponding resonance coinciding frequency band range are output.

[0068] In the resonance coinciding frequency band range, the embodiment extracts frequency points, amplitudes and phase data of the high-frequency distortion frequency band marked in the current distortion frequency component distribution data, and combines the oscillation amplitude and decay rate of the same frequency band in the voltage oscillation characteristic parameters to determine a main resonance frequency by taking the intersection of the frequency points. Based on the amplitude-phase distribution of the main resonance frequency point, the embodiment generates an oscillation amplitude envelope of the resonance natural frequency and a phase mutation interval to obtain a high-frequency resonance natural frequency oscillation distribution data set. The high-frequency resonance natural frequency oscillation distribution data set can include, but is not limited to, a main resonance frequency point, a resonance amplitude envelope (a distribution curve of the amplitude varying with the frequency), a phase mutation interval and a resonance modal energy proportion. The phase mutation interval is a frequency range in which the phase angle jumps more than 45°. The resonance modal energy proportion is a percentage of high-frequency distortion energy in total distortion energy.

[0069] S2. Determine an active resonance suppression delay factor based on the high-frequency resonance natural frequency oscillation distribution data, and obtain a preliminary damping value under the equivalent series resistance effect according to the active resonance suppression delay factor and the grid-connected power smoothing constraint condition.

[0070] In some embodiments, the step of determining the active resonance suppression delay factor based on the high-frequency resonance natural frequency oscillation distribution data includes:

[0071] Obtaining measured reactance parameters of a filter in a direct-drive wind turbine grid-connected inverter system, and determining a main resonant frequency point based on the high-frequency resonant natural frequency oscillation distribution data;

[0072] Extracting equivalent reactance distribution data of the filter at the main resonant frequency point according to the measured reactance parameters of the filter;

[0073] Based on the equivalent reactance distribution data, fitting the reactance-frequency relationship by the least squares method to generate a reactance-frequency characteristic model;

[0074] Determining the impedance mutation degree of the high-frequency resonant frequency band according to the impedance change rate of the reactance-frequency characteristic model, and determining the impedance mutation frequency band range according to the impedance mutation degree and a preset mutation threshold;

[0075] In the impedance mutation frequency range, using the main resonant frequency point to calculate the initial value of the active damping gain under the phase compensation angle constraint;

[0076] It is determined whether the initial value of the active damping gain satisfies a preset phase margin stability condition. If so, an active resonance suppression delay factor is obtained based on the initial value of the active damping gain using a phase compensation relationship.

[0077] Specifically, based on the main resonance frequency point in the high-frequency resonance natural frequency oscillation distribution data set, the filter measured reactance parameters of the inductance-capacitance-inductance type filter configured in the direct-driven wind turbine grid-connected inverter (i.e. the LCL filter located between the output end of the grid-connected inverter and the power grid) are obtained. For example, the filter measured reactance parameters can include the machine-side inductance value, the machine-side capacitance value, and the grid-side inductance value. The embodiment combines the filter measured reactance parameters of the inductance-capacitance-inductance type filter to calculate the equivalent inductive reactance and capacitive reactance components of the filter at the main resonance frequency point, generate the equivalent reactance distribution data of the filter in the high-frequency resonance frequency band, and based on the equivalent reactance distribution data, perform polynomial fitting on the reactance-frequency relationship by the least square method to generate a reactance-frequency characteristic model. The reactance-frequency characteristic model represents the impedance characteristic of the filter in the resonance frequency band, which reflects the law of the change of the filter impedance with frequency. According to the first derivative (i.e. the impedance change rate) of the reactance-frequency characteristic model, the embodiment determines the change slope of the impedance with frequency in the high-frequency resonance frequency band, and judges the degree of impedance mutation in the high-frequency resonance frequency band according to the impedance change rate. If the impedance change rate exceeds a preset mutation threshold (for example, 10 Ω / Hz), it is determined that there is an impedance mutation, and phase compensation is required. At this time, an impedance mutation flag signal and an impedance mutation frequency range are output. Then, according to the impedance mutation frequency range, the embodiment calculates an active damping gain initial value that satisfies the phase compensation angle constraint by the phase compensation relationship (the product of the time delay factor and the resonance frequency needs to satisfy that the phase compensation angle is not more than a phase compensation angle constraint value, which can be set to 90°). The specific calculation formula of the active damping gain initial value is:

[0078]

[0079] In the formula, is the active damping gain initial value, which is dimensionless; is the radian value corresponding to the phase compensation angle constraint value; is a preset empirical time delay factor, which is in seconds; is the main resonance frequency.

[0080] Then, based on the pole distribution of the system open-loop transfer function, the embodiment verifies whether the active damping gain initial value satisfies the phase margin stability condition that the phase margin is not less than 45°. If it is satisfied, the active resonance suppression time delay factor is output according to the active damping gain initial value by the inverse phase compensation relationship. Specifically, the embodiment substitutes the active damping gain initial value into the system open-loop transfer function to calculate the corresponding phase margin. If the phase margin is not less than 45°, the active resonance suppression time delay factor is inversely calculated according to the phase compensation relationship. The specific calculation formula is:

[0081]

[0082] In the formula, is an active resonance suppression time delay factor; is an arc value corresponding to an actual phase compensation angle.

[0083] If the initial value of the active damping gain does not satisfy the phase margin stability condition that the phase margin is not less than 45°, the high-frequency resonance natural frequency oscillation distribution data is reacquired, and the active resonance suppression time delay factor is determined through the high-frequency resonance natural frequency oscillation distribution data. It should be noted that the active damping control suppresses the resonance by introducing a virtual impedance (equivalent series resistance), and the effect is equivalent to adding a phase compensation in the system; the phase compensation angle is defined as the phase lag introduced by the virtual impedance, which needs to offset the phase jump caused by the resonance.

[0084] In some embodiments, the step of acquiring the preliminary damping value under the effect of the equivalent series resistance according to the active resonance suppression time delay factor and the grid-connected power smoothing constraint condition comprises:

[0085] The grid-connected power smoothing constraint condition of the direct-drive wind turbine grid-connected inverter system is acquired, and the grid-connected power smoothing constraint condition is quantified as a joint index in the frequency domain and the time domain to generate a grid-connected power smoothing constraint parameter set;

[0086] The equivalent series resistance is obtained according to the active resonance suppression time delay factor and the main resonance frequency point;

[0087] The equivalent series resistance is input into the closed-loop transfer function of the direct-drive wind turbine grid-connected inverter system, and the corresponding grid-side current harmonic distortion rate and active power fluctuation rate are calculated;

[0088] The grid-side current harmonic distortion rate and the active power fluctuation rate are compared with the grid-connected power smoothing constraint parameter set respectively, and the active damping gain value corresponding to the current equivalent series resistance is extracted when the grid-side current harmonic distortion rate and the active power fluctuation rate both satisfy the grid-connected power smoothing constraint parameter set;

[0089] The active damping gain value corresponding to the current equivalent series resistance is taken as the preliminary damping value under the effect of the equivalent series resistance.

[0090] Specifically, the embodiment obtains grid-connected power smoothing constraint conditions of the direct-drive wind turbine grid-connected inverter system according to power smoothing constraint conditions required by the direct-drive wind turbine grid-connected inverter system during operation, to ensure system stability and power quality. The grid-connected power smoothing constraint conditions can include active power fluctuation rate constraint conditions, total harmonic distortion rate constraint conditions, and dynamic response time constraint conditions. For example, the active power fluctuation rate constraint conditions can be that the percentage of grid-connected active power change in adjacent cycles should not be greater than 2% of the rated power, the total harmonic distortion rate constraint conditions can be that the grid-side current harmonic distortion rate should not be greater than 5%, and the dynamic response time constraint conditions can be that the time from disturbance to recovery of the system should be less than 100 ms. The embodiment quantifies the above grid-connected power smoothing constraint conditions into a frequency-time domain joint index, for example, quantifies the above grid-connected power smoothing constraint conditions into active power fluctuation rate threshold limits and total harmonic distortion rate threshold limits, to generate a grid-connected power smoothing constraint parameter set. According to the active damping principle, the embodiment is equivalent to a series resistance effect through a virtual impedance. The specific calculation formula of the equivalent series resistance value is:

[0091]

[0092] wherein, is the equivalent series resistance value; is the active damping gain. The initial value of the active damping gain can be set to 1; is the active resonance suppression time delay factor; is the main resonance frequency.

[0093] In the embodiment, the active damping is equivalent to a series resistance effect through a virtual impedance, but it is necessary to ensure that the virtual impedance value provides sufficient damping effect in the resonance frequency band, while not deteriorating the system dynamic response. The embodiment substitutes the equivalent series resistance value into the closed-loop transfer function of the direct-drive wind turbine grid-connected inverter system to obtain the frequency response characteristics of the system. The corresponding grid-side current harmonic distortion rate is calculated by analyzing the frequency response characteristics, and the percentage of power change in adjacent cycles is calculated by time domain simulation to obtain the active power fluctuation rate. Assuming that the open-loop transfer function of the system is G(s), the closed-loop transfer function after adding the equivalent series resistance value is:

[0094]

[0095] wherein, is the closed-loop transfer function of the direct-drive wind turbine grid-connected inverter system.

[0096] In this embodiment, the grid-side current harmonic distortion rate and the active power fluctuation rate are respectively compared with the grid-connected power smoothing constraint parameter set. When the grid-side current harmonic distortion rate and the active power fluctuation rate both satisfy the grid-connected power smoothing constraint parameter set, the active damping gain value corresponding to the current equivalent series resistance is extracted. For example, if the grid-side current harmonic distortion rate is not greater than 5% and the active power fluctuation rate is not greater than 2%, the active damping gain value corresponding to the current equivalent series resistance is extracted as a preliminary damping value under the equivalent series resistance effect. If either the grid-side current harmonic distortion rate or the active power fluctuation rate does not satisfy the grid-connected power smoothing constraint parameter set, the active damping gain value is adjusted using a gradient descent method until the grid-connected power smoothing constraint parameter set is satisfied.

[0097] S3. Superimposing the preliminary damping value with the pre-acquired grid voltage fluctuation influence factor to obtain a superposition result, and dynamically compensating and adjusting the active resonance suppression delay factor according to the superposition result to obtain a high-frequency resonance characteristic value.

[0098] In some embodiments, the step of dynamically compensating and adjusting the active resonance suppression delay factor according to the superposition result to obtain a high-frequency resonance characteristic value includes:

[0099] According to the superposition result, adjusting the active resonance suppression delay factor through a linear compensation relationship to obtain a corrected value of the active resonance suppression delay factor;

[0100] Using the active resonance suppression delay factor correction value to adjust the delay compensation amount of the pulse modulation signal in the grid-connected inverter controller in real time;

[0101] Delay compensation closed-loop control is performed according to the delay compensation amount, grid-side current time series data after closed-loop control is obtained, and spectrum analysis is performed on the grid-side current time series data to extract high-frequency resonance characteristic values.

[0102] Specifically, this embodiment performs statistical analysis on the grid voltage fluctuation data, calculates the standard deviation and probability distribution of its fluctuation amplitude, generates a grid voltage fluctuation influence factor, and superimposes the preliminary damping value under the equivalent series resistance effect and the grid voltage fluctuation influence factor according to a weight ratio to generate a superposition result. Then, this embodiment adjusts the active resonance suppression delay factor through a linear compensation relationship based on the superposition result. The specific calculation formula can be:

[0103]

[0104] Where, is the correction value of active resonance suppression delay factor; is the active resonance suppression delay factor; a compensation coefficient, which is used to adjust the degree of influence of the superposition result on the active resonance suppression time delay factor, can be set by a person skilled in the art according to experience; a superposition result.

[0105] The embodiment inputs the active resonance suppression time delay factor correction value that is dynamically corrected into an active damping module of a direct-drive wind turbine grid-connected inverter controller, adjusts the time delay compensation amount of a pulse modulation signal in real time through the active damping module, suppresses high-frequency resonance through closed-loop control, collects grid-side current time sequence data after closed-loop control, and extracts a resonance frequency point, a resonance amplitude value and a phase mutation interval from the grid-side current time sequence data through frequency spectrum analysis, where the resonance frequency point is a main frequency point of high-frequency resonance whose amplitude value exceeds 3% of a fundamental wave amplitude value, the resonance amplitude value is a percentage of a frequency spectrum amplitude value relative to the fundamental wave amplitude value, and the phase mutation interval is a frequency range in which a phase angle jump exceeds 45°, thereby generating a high-frequency resonance characteristic value.

[0106] S4. Calculate a frequency drift offset amount according to a difference between the high-frequency resonance characteristic value and an upper limit value of a bandwidth of the grid-connected inverter controller.

[0107] S5. When the frequency drift offset amount exceeds a preset drift threshold range, optimize the active damping gain parameter with a minimization of a resonance peak value and a maximization of a dynamic response margin as optimization objectives, and output an optimized set of high-frequency resonance active suppression parameters.

[0108] S6. Perform high-frequency resonance active suppression on the direct-drive wind turbine grid-connected inverter system by using the optimized set of high-frequency resonance active suppression parameters.

[0109] In some embodiments, the step of optimizing the active damping gain parameter with the minimization of the resonance peak value and the maximization of the dynamic response margin as the optimization objectives, and outputting the optimized set of high-frequency resonance active suppression parameters comprises:

[0110] defining the active damping gain parameter as a decision variable, and setting an optimization range of the active damping gain parameter;

[0111] randomly generating a plurality of particles in the optimization range of the active damping gain parameter with the minimization of the resonance peak value and the maximization of the dynamic response margin as the optimization objectives, to form an initial particle group;

[0112] inputting the active damping gain parameter of each particle into the grid-connected inverter controller, obtaining a resonance peak value through closed-loop simulation, calculating a phase margin and an amplitude margin under the current active damping gain parameter to obtain a dynamic response margin;

[0113] calculating a current fitness value of each particle according to the resonance peak value and the dynamic response margin, and updating an individual extreme value position according to the current fitness value of each particle.

[0114] finding a global optimal solution among all individual extreme value positions of the particles, updating the global extreme value position by the global optimal solution, and updating the speed and position of each particle according to the updated individual extreme value position and the global extreme value position;

[0115] repeating the above steps until the fitness value converges, outputting the active damping gain parameter combination corresponding to the global optimal extreme value position, and forming an active suppression parameter optimization set of high-frequency resonance.

[0116] Specifically, based on the main resonance frequency point in the high-frequency resonance natural frequency oscillation data set and the stability analysis result of the system closed-loop transfer function, according to the engineering experience and system constraints (such as the physically realizable range of damping gain), the optimization range of the active damping gain parameter is set. In the direct-drive wind turbine grid-connected inverter system, the active damping gain parameter is usually realized through the parameter adjustment of the proportional-integral-derivative control algorithm, and the optimization goal is defined as minimizing the resonance peak value and maximizing the dynamic response margin. In the optimization range of the active damping gain parameter, a random number generation method is used to randomly generate a number of particles, assuming that N=50 particles are generated, each particle represents a combination of active damping gain parameters, forming an initial particle swarm. Then the active damping gain parameters of each particle are input into the grid-connected inverter controller, and the grid-side current spectrum data is generated through closed-loop simulation. The frequency domain analysis is performed on the grid-side current spectrum data, and the maximum amplitude value in the high-frequency resonance frequency band is extracted, and the percentage of the maximum resonance peak value relative to the fundamental amplitude value is calculated, and the maximum resonance peak value is obtained, wherein the resonance peak value refers to the amplitude of the grid-side current at the resonance frequency. At the same time, in the simulation process, based on the system open-loop transfer function model, the frequency response analysis method is used to calculate the phase margin and amplitude margin under the current active damping gain parameter, wherein the phase margin refers to the magnitude of the amplitude when the phase angle of the system open-loop frequency response reaches-180°, and the amplitude margin refers to the magnitude of the phase angle when the amplitude of the system open-loop frequency response reaches 0dB. The smaller value of the phase margin and the amplitude margin is taken as the dynamic response margin, for example, the phase margin is 48°, and the amplitude margin is 7dB, then the dynamic response margin is 48°. The fitness function of each particle is defined as the weighted sum of the inverse of the resonance peak value and the dynamic response margin. Then the current fitness value of the particle is compared with the historical optimal value, and the individual extreme value position is updated. The global optimal solution is selected from all individual extreme values, and the global extreme value position is updated through the global optimal solution. The particle position is updated according to the particle speed update formula. When the change rate of the fitness value is less than the preset convergence threshold for several times in succession, the optimization is terminated, and the high-frequency resonance active suppression parameter optimization set corresponding to the global optimal extreme value position is output. The harmonic distortion rate and the dynamic response margin under the parameter combination are verified through closed-loop simulation. If the verification is passed, the high-frequency resonance active suppression parameter optimization set is output. The high-frequency resonance active suppression parameter optimization set includes the optimized active damping gain parameter and its corresponding resonance peak value and phase margin.

[0117] The embodiment of the present application provides a high-frequency resonance dynamic suppression method for a direct-drive wind turbine grid-connected inverter, the method comprising the following steps: extracting high-frequency resonance natural frequency oscillation distribution data from collected grid-side current data and grid-connected inverter output voltage waveform data; determining an active resonance suppression time delay factor based on the high-frequency resonance natural frequency oscillation distribution data, and obtaining a preliminary damping value under the effect of an equivalent series resistance according to the active resonance suppression time delay factor and a grid-connected power smoothing constraint condition; superimposing the preliminary damping value and a grid voltage fluctuation influence factor obtained in advance to obtain a superimposition result, and dynamically compensating and adjusting the active resonance suppression time delay factor according to the superimposition result to obtain a high-frequency resonance characteristic value; calculating a frequency drift offset according to the difference between the high-frequency resonance characteristic value and an upper limit value of a bandwidth of a grid-connected inverter controller; when the frequency drift offset exceeds a preset drift threshold range, optimizing an active damping gain parameter to minimize a resonance peak value and maximize a dynamic response margin as an optimization target, and outputting a high-frequency resonance active suppression parameter optimization set; and using the high-frequency resonance active suppression parameter optimization set to perform high-frequency resonance active suppression on a direct-drive wind turbine grid-connected inverter system. Compared with the prior art, the method realizes effective suppression of high-frequency resonance of the direct-drive wind turbine grid-connected inverter system under complex working conditions by optimizing the active damping gain parameter, improves overall operation performance of the system, and guarantees safe and stable operation of the system.

[0118] It should be noted that the size of the serial number of each process does not mean the order of execution, and the execution order of each process should be determined according to its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

[0119] In one embodiment, as shown in FIG. 1, Figure 2 The embodiment of the present application provides a high-frequency resonance dynamic suppression system for a direct-drive wind turbine grid-connected inverter, the system comprising:

[0120] The data acquisition module 101 is configured to extract high-frequency resonance natural frequency oscillation distribution data from collected grid-side current data and grid-connected inverter output voltage waveform data.

[0121] The damping analysis module 102 is configured to determine an active resonance suppression time delay factor based on the high-frequency resonance natural frequency oscillation distribution data, and obtain a preliminary damping value under the effect of an equivalent series resistance according to the active resonance suppression time delay factor and a grid-connected power smoothing constraint condition.

[0122] The dynamic compensation module 103 is configured to superimpose the preliminary damping value and a grid voltage fluctuation influence factor obtained in advance to obtain a superimposition result, and dynamically compensate and adjust the active resonance suppression time delay factor according to the superimposition result to obtain a high-frequency resonance characteristic value.

[0123] a drift analysis module 104, configured to calculate a frequency drift offset according to a difference between the high-frequency resonance characteristic value and an upper limit value of a bandwidth of the grid-connected inverter controller;

[0124] a parameter optimization module 105, configured to, when the frequency drift offset exceeds a preset drift threshold range, perform parameter optimization on an active damping gain parameter with an optimization target of minimizing a resonance peak value and maximizing a dynamic response margin, and output a high-frequency resonance active suppression parameter optimization set;

[0125] a resonance suppression module 106, configured to perform high-frequency resonance active suppression on the direct-drive wind turbine grid-connected inverter system by using the high-frequency resonance active suppression parameter optimization set.

[0126] The specific limitations of the direct-drive wind turbine grid-connected inverter high-frequency resonance dynamic suppression system can refer to the limitations of the direct-drive wind turbine grid-connected inverter high-frequency resonance dynamic suppression method described above, which will not be repeated here. Those skilled in the art can realize that the various modules and steps described in combination with the embodiments disclosed in the present application can be realized in hardware, software or a combination of both. Whether the functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0127] The embodiment of the application provides a high-frequency resonance dynamic suppression system of a direct-drive wind turbine grid-connected inverter, a data acquisition module of the system extracts high-frequency resonance natural frequency oscillation distribution data from collected grid-side current data and grid-connected inverter output voltage waveform data; a damping analysis module determines an active resonance suppression time delay factor based on the high-frequency resonance natural frequency oscillation distribution data, and obtains a preliminary damping value under an equivalent series resistance effect according to the active resonance suppression time delay factor and a grid-connected power smoothing constraint condition; a dynamic compensation module superimposes the preliminary damping value and a grid voltage fluctuation influence factor obtained in advance to obtain a superposition result, and dynamically compensates and adjusts the active resonance suppression time delay factor according to the superposition result to obtain a high-frequency resonance characteristic value; a drift analysis module calculates a frequency drift offset amount according to a difference between the high-frequency resonance characteristic value and an upper limit value of a bandwidth of a grid-connected inverter controller; a parameter optimization module optimizes an active damping gain parameter when the frequency drift offset amount exceeds a preset drift threshold range, taking minimization of a resonance peak value and maximization of a dynamic response margin as optimization objectives, and outputs a high-frequency resonance active suppression parameter optimization set; and a resonance suppression module performs high-frequency resonance active suppression on the direct-drive wind turbine grid-connected inverter system by using the high-frequency resonance active suppression parameter optimization set. Compared with the prior art, the system realizes effective suppression of high-frequency resonance of the direct-drive wind turbine grid-connected inverter system under complex working conditions by optimizing the active damping gain parameter, improves overall operation performance of the system, and guarantees safe and stable operation of the system.

[0128] The above-described embodiments only express several preferred embodiments of the application, which are described in detail and specifically, but should not be understood as a limitation on the patent scope of the application. It should be pointed out that, for ordinary skilled persons in the technical field, several improvements and replacements can be made without departing from the technical principles of the application, and these improvements and replacements should be regarded as the protection scope of the application. Therefore, the patent protection scope of the application should be subject to the protection scope of the claims.

Claims

1. A method for dynamically suppressing high-frequency resonance of a direct-drive wind turbine grid-connected inverter, characterized in that: The following steps are involved: Extracting high-frequency resonant natural frequency oscillation distribution data from the collected grid-side current data and grid-connected inverter output voltage waveform data; When it is determined that high-frequency resonance occurs, the high-frequency resonance natural frequency oscillation distribution data is determined based on the current distortion frequency component distribution data and the voltage oscillation characteristic parameters in the high-frequency resonance coincidence frequency band; Determining an active resonance suppression delay factor based on the high-frequency resonance natural frequency oscillation distribution data, and obtaining a preliminary damping value under an equivalent series resistance effect according to the active resonance suppression delay factor and a grid-connected power smoothing constraint condition; The step of determining the active resonance suppression delay factor based on the high-frequency resonance natural frequency oscillation distribution data includes: Obtaining measured reactance parameters of a filter in a direct-drive wind turbine grid-connected inverter system, and determining a main resonant frequency point based on the high-frequency resonant natural frequency oscillation distribution data; Extracting equivalent reactance distribution data of the filter at the main resonant frequency point according to the measured reactance parameters of the filter; Based on the equivalent reactance distribution data, fitting the reactance-frequency relationship by the least squares method to generate a reactance-frequency characteristic model; Determining the impedance mutation degree of the high-frequency resonant frequency band according to the impedance change rate of the reactance-frequency characteristic model, and determining the impedance mutation frequency band range according to the impedance mutation degree and a preset mutation threshold; In the impedance mutation frequency range, using the main resonant frequency point to calculate the initial value of the active damping gain under the phase compensation angle constraint; Determining whether the initial value of the active damping gain satisfies a preset phase margin stability condition, and if so, obtaining an active resonance suppression delay factor based on the initial value of the active damping gain using a phase compensation relationship; Superimposing the preliminary damping value with the pre-acquired grid voltage fluctuation influence factor to obtain a superposition result, and dynamically compensating and adjusting the active resonance suppression delay factor according to the superposition result to obtain a high-frequency resonance characteristic value; Calculating a frequency drift offset according to a difference between the high-frequency resonance characteristic value and a bandwidth upper limit value of the grid-connected inverter controller; When the frequency drift offset exceeds a preset drift threshold range, optimizing the active damping gain parameters with minimizing the resonance peak and maximizing the dynamic response margin as optimization goals, and outputting an optimized set of high-frequency resonance active suppression parameters; The high-frequency resonance active suppression parameter optimization set is used to perform high-frequency resonance active suppression on a direct-drive wind turbine grid-connected inverter system.

2. The method for dynamically suppressing high-frequency resonance of a direct-drive wind turbine grid-connected inverter according to claim 1, characterized in that: The step of extracting high-frequency resonant natural frequency oscillation distribution data from the collected grid-side current data and grid-connected inverter output voltage waveform data includes: Collect grid-side current data and grid-connected inverter output voltage waveform data, and use a sliding window mean filter algorithm to remove high-frequency noise from the grid-side current data to obtain grid-side denoised current data; performing amplitude normalization processing on the output voltage waveform data of the grid-connected inverter to obtain standardized voltage waveform data; Performing spectrum analysis on the grid-side de-noised current data using a fast Fourier transform to obtain a frequency domain amplitude spectrum, and extracting distribution data of current distortion frequency components of each harmonic component and a high-frequency band based on the amplitudes of the frequency components in the frequency domain amplitude spectrum; Waveform analysis is performed on the standardized voltage waveform data to extract voltage oscillation characteristic parameters.

3. The method for dynamically suppressing high-frequency resonance of a direct-drive wind turbine grid-connected inverter according to claim 1, characterized in that: The step of obtaining a preliminary damping value under the equivalent series resistance effect according to the active resonance suppression delay factor and the grid-connected power smoothing constraint condition includes: Obtaining a grid-connected power smoothing constraint condition of a direct-drive wind turbine grid-connected inverter system, quantifying the grid-connected power smoothing constraint condition into a frequency-domain-time-domain joint indicator, and generating a grid-connected power smoothing constraint parameter set; Obtaining an equivalent series resistance according to the active resonance suppression delay factor and the main resonance frequency point; Inputting the equivalent series resistance into the closed-loop transfer function of the direct-drive wind turbine grid-connected inverter system to calculate the corresponding grid-side current harmonic distortion rate and active power fluctuation rate; comparing the grid-side current harmonic distortion rate and the active power fluctuation rate with the grid-connected power smoothing constraint parameter set, and extracting an active damping gain value corresponding to a current equivalent series resistance when both the grid-side current harmonic distortion rate and the active power fluctuation rate satisfy the grid-connected power smoothing constraint parameter set; The active damping gain value corresponding to the current equivalent series resistance is used as the preliminary damping value under the equivalent series resistance effect.

4. The method for dynamically suppressing high-frequency resonance of a direct-drive wind turbine grid-connected inverter according to claim 3, characterized in that: The grid-connected power smoothing constraint condition includes at least an active power fluctuation rate constraint condition and a total harmonic distortion rate constraint condition.

5. The method for dynamically suppressing high-frequency resonance of a direct-drive wind turbine grid-connected inverter according to claim 1, characterized in that: The step of dynamically compensating and adjusting the active resonance suppression delay factor according to the superposition result to obtain a high-frequency resonance characteristic value includes: According to the superposition result, adjusting the active resonance suppression delay factor through a linear compensation relationship to obtain a corrected value of the active resonance suppression delay factor; Using the active resonance suppression delay factor correction value to adjust the delay compensation amount of the pulse modulation signal in the grid-connected inverter controller in real time; Delay compensation closed-loop control is performed according to the delay compensation amount, grid-side current time series data after closed-loop control is obtained, and spectrum analysis is performed on the grid-side current time series data to extract high-frequency resonance characteristic values.

6. A method for dynamically suppressing high-frequency resonance of a direct-drive wind turbine grid-connected inverter according to claim 5, characterized in that: The high-frequency resonance characteristic values ​​include the resonance frequency point, resonance amplitude and phase mutation interval obtained by dynamic compensation after superimposing the power grid fluctuation.

7. The method for dynamically suppressing high-frequency resonance of a direct-drive wind turbine grid-connected inverter according to claim 1, characterized in that: The steps of optimizing the active damping gain parameters with minimizing the resonance peak and maximizing the dynamic response margin as the optimization goals and outputting the optimized set of high-frequency resonance active suppression parameters include: Define the active damping gain parameter as a decision variable and set the optimization range of the active damping gain parameter; With the optimization goals of minimizing the resonance peak and maximizing the dynamic response margin, several particles are randomly generated within the optimization range of the active damping gain parameter to form an initial particle swarm. The active damping gain parameter of each particle is input into the grid-connected inverter controller. The resonance peak is obtained through closed-loop simulation. The phase margin and amplitude margin under the current active damping gain parameter are calculated to obtain the dynamic response margin. Calculating a current fitness value of each particle according to the resonance peak value and the dynamic response margin, and updating an individual extreme value position according to the current fitness value of each particle; Finding a global optimal solution among the individual extreme value positions of all particles, updating the global extreme value position according to the global optimal solution, and updating the speed and position of each particle according to the updated individual extreme value position and the global extreme value position; Repeat the above steps until the fitness value converges, and output the active damping gain parameter combination corresponding to the global optimal extreme value position to form the optimized set of high-frequency resonance active suppression parameters.

8. The method for dynamically suppressing high-frequency resonance of a direct-drive wind turbine grid-connected inverter according to claim 7, characterized in that: The fitness function of each particle is defined as the weighted sum of the inverse of the resonance peak and the dynamic response margin.

9. A high-frequency resonance dynamic suppression system for a direct-drive wind turbine grid-connected inverter, characterized in that: The system comprises: A data acquisition module is used to extract high-frequency resonant natural frequency oscillation distribution data from the collected grid-side current data and grid-connected inverter output voltage waveform data; When it is determined that high-frequency resonance occurs, the high-frequency resonance natural frequency oscillation distribution data is determined based on the current distortion frequency component distribution data and the voltage oscillation characteristic parameters in the high-frequency resonance coincidence frequency band; a damping analysis module, configured to determine an active resonance suppression delay factor based on the high-frequency resonance natural frequency oscillation distribution data, and obtain a preliminary damping value under an equivalent series resistance effect according to the active resonance suppression delay factor and a grid-connected power smoothing constraint condition; The step of determining the active resonance suppression delay factor based on the high-frequency resonance natural frequency oscillation distribution data includes: Obtaining measured reactance parameters of a filter in a direct-drive wind turbine grid-connected inverter system, and determining a main resonant frequency point based on the high-frequency resonant natural frequency oscillation distribution data; Extracting equivalent reactance distribution data of the filter at the main resonant frequency point according to the measured reactance parameters of the filter; Based on the equivalent reactance distribution data, fitting the reactance-frequency relationship by the least squares method to generate a reactance-frequency characteristic model; Determining the impedance mutation degree of the high-frequency resonant frequency band according to the impedance change rate of the reactance-frequency characteristic model, and determining the impedance mutation frequency band range according to the impedance mutation degree and a preset mutation threshold; In the impedance mutation frequency range, using the main resonant frequency point to calculate the initial value of the active damping gain under the phase compensation angle constraint; Determining whether the initial value of the active damping gain satisfies a preset phase margin stability condition, and if so, obtaining an active resonance suppression delay factor based on the initial value of the active damping gain using a phase compensation relationship; a dynamic compensation module, configured to superimpose the preliminary damping value with a pre-acquired grid voltage fluctuation influence factor to obtain a superposition result, and dynamically compensate and adjust the active resonance suppression delay factor according to the superposition result to obtain a high-frequency resonance characteristic value; a drift analysis module, configured to calculate a frequency drift offset based on a difference between the high-frequency resonance characteristic value and a bandwidth upper limit value of the grid-connected inverter controller; a parameter optimization module for optimizing the active damping gain parameters with the optimization objectives of minimizing the resonance peak and maximizing the dynamic response margin when the frequency drift offset exceeds a preset drift threshold range, and outputting an optimized set of high-frequency resonance active suppression parameters; The resonance suppression module is used to perform high-frequency resonance active suppression on a direct-drive wind turbine grid-connected inverter system using the high-frequency resonance active suppression parameter optimization set.

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