Wind power grid-connected oscillation suppression method and system based on an adaptive damping controller

Abstract

The present invention discloses a method and system for suppressing wind power grid connection oscillations based on an adaptive damping controller, which relates to the technical field of power system oscillation suppression. The present invention designs the structure of the adaptive damping controller and completes parameter tuning; then builds a simulation model of the wind power grid connection system; after collecting voltage signals, uses the FFT processing method to identify the oscillation frequency and determine whether there is an unstable oscillation mode in the system; if there is an unstable oscillation, an adaptive damping controller is connected between the wind farm side and the grid side; the adaptive damping controller filters out the signal components causing system oscillations and performs phase modulation; the signal components generated by the adaptive damping controller are injected into the grid to cancel the original signals, achieving oscillation suppression. The adaptive damping controller designed by the present invention can make full use of measurement data by introducing an oscillation frequency identification module and a phase shift parameter calculation module, adjust the parameters of the control link according to the change of the vibration frequency, and effectively suppress oscillations.

Description

Technical Field

[0001] The present invention relates to the technical field of power system oscillation suppression, and specifically to a method and system for suppressing wind power grid-connected oscillation based on an adaptive damping controller. Background Art

[0002] Renewable energy power generation systems based on wind energy have the advantages of wide resource distribution, high energy utilization efficiency, and mature equipment technology. Their status in the power system is changing from an auxiliary power source to a main power source. However, the long-distance transmission or DC transmission of wind power has led to the characteristics of the power grid connected to wind power evolving from a single-machine infinite system to a weak grid characteristic or a power electronic characteristic. The interaction between the wind power system and the power grid will jointly affect the stability of the power system.

[0003] The frequent occurrence of low-frequency oscillation and sub- / supra-synchronous oscillation accidents has further attracted the attention of researchers to the high-frequency interaction problem between wind turbines and the power grid. Accurately and quickly detecting system oscillation phenomena and taking oscillation suppression measures are the basis for the safe operation of the power grid. However, there are some practical problems in the current research on oscillation suppression technology that have not been considered.

[0004] The oscillation frequency has a time-varying characteristic. For example, under different shunt compensation capacitors in the power grid, the system oscillation frequency may shift, and the existing oscillation suppression technology can only improve the damping for the designed frequency points. Although frequency acquisition can be achieved through online frequency detection or an adaptive frequency-locked loop, traditional online frequency detection methods include the Fourier algorithm, wavelet analysis method, adaptive window function method, etc., which have problems such as large computational complexity and poor detection following performance. There is a contradiction between the accuracy and rapidity in the resonant frequency detection based on an adaptive notch filter frequency-locked loop. Therefore, the present invention proposes a method and system for suppressing wind power grid-connected oscillation based on an adaptive damping controller. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and system for suppressing wind power grid-connected oscillation based on an adaptive damping controller, which can effectively suppress oscillations under different oscillation frequency bands and grid conditions, and has good adaptability and practicality.

[0006] According to the first aspect of the present invention, to achieve the above object, the present invention provides the following technical solution: A method for suppressing wind power grid-connected oscillation based on an adaptive damping controller, comprising the following steps:

[0007] Introduce an oscillation frequency identification module and a phase shift parameter calculation module into the damping controller structure to construct an adaptive damping controller, analyze the damping characteristics of the wind power grid-connected system, and complete the parameter tuning of the adaptive damping controller;

[0008] Construct a simulation model of the wind power grid-connected system and conduct parameter design;

[0009] Receive the voltage signal collected by the wind power grid-connected system simulation model, process the signal using the fast Fourier transform to identify the oscillation frequency, and determine whether there is an unstable oscillation mode in the wind power grid-connected system. If there is an unstable oscillation, connect an adaptive damping controller between the wind farm side and the grid side;

[0010] The adaptive damping controller filters out the signal components that cause oscillations in the wind power grid-connected system, performs phase modulation and then injects them into the grid to cancel out the original signal, achieving oscillation suppression.

[0011] Furthermore, an oscillation frequency identification module and a phase shift parameter calculation module are introduced into the damping controller structure to construct an adaptive damping controller, specifically as follows:

[0012] (21) Analyze the damping characteristics of the wind power grid-connected system to obtain the oscillation suppression mechanism for connecting the damping controller, specifically as follows:

[0013] (21.1) Equivalent the adaptive damping controller to a controllable impedance with the electric field bus voltage u and the line current i as feedback signals. Based on the FFT signal processing method, identify the oscillation frequency, obtain the oscillation mode damping, generate three-phase current injection into the grid by connecting the adaptive damping controller, and thus adjust the damping characteristics of the system at the oscillation frequency point to achieve wide-frequency oscillation suppression;

[0014] (21.2) After the adaptive damping controller is connected to the system, the total impedance of the system is:

[0015]

[0016] In the formula: Z W is the equivalent impedance on the wind farm side; Z N is the equivalent impedance on the grid side; H i and H u are the transfer functions of the current feedback signal i and the voltage feedback signal u respectively;

[0017] (22) Design the damping calculator structure, specifically including a band-stop filter, a band-pass filter, a proportional phase shift link, and a limiter. Use the damping calculator to generate a reference signal for suppressing wide-frequency oscillations according to the feedback signal;

[0018] (23) Design the current generator structure, specifically including a cascaded converter, a controller, and a step-up transformer. The current generator receives the reference signal provided by the damping calculator, controls the generation of three-phase current through the converter, and injects it into the power grid.

[0019] (24) Based on the damping controller, the oscillation frequency identification module dynamically monitors the current signal to capture the oscillation frequency in the power grid, and then it is used by the phase shift parameter calculation module to dynamically adjust the time constant of the controller, realizing the adaptive adjustment of the proportional phase shift link, specifically as follows:

[0020] (24.1) The DC voltage set value U dc_ref is used as the input signal, and after passing through the proportional gain K p_out of the outer loop and the integral gain K i_out of the outer loop, the grid-side d axis current set value I gd_ref is calculated. It is compared with the grid-side d axis current component I gd to filter out the oscillation signal i abc ;

[0021] (24.2) U dc is used as the input signal of the adaptive damping controller. First, the signal components causing system oscillation are filtered out through a filter, and then the signal is precisely phase-adjusted through the proportional phase shift link to ensure its synchronization with the system oscillation frequency, obtaining and then injecting it into the power grid to cancel out the original oscillation signal, completing the oscillation suppression process;

[0022] (25) Design the parameters of the damping controller, including determining the transfer function of the band-pass filter and the parameter tuning of the proportional phase shift link;

[0023] (26) Construct an equivalent RLC circuit for the wind power grid-connected system, complete the design of the phase shift parameter calculation link according to the equivalent impedance size, and construct a complete adaptive damping controller.

[0024] Further, the damping calculator generates a reference signal for suppressing broadband oscillation according to the feedback signal, specifically as follows:

[0025] (31) Use a band-stop filter and a band-pass filter to filter out the power frequency components in the feedback signal to achieve signal extraction, then use the proportional phase shift link to process the signal, and synthesize the required current reference signal through an adder ;

[0026] The relationship between the output of the damping calculator and the input signal is as follows:

[0027]

[0028]

[0029]

[0030] In the formula: i represents the current input signal; u represents the voltage input signal; represents the gain of the current frequency signal; represents the phase shift of the current frequency signal; represents the gain of the voltage frequency signal; represents the phase shift of the voltage frequency signal; transfer function H i ( s ) represents the gain and phase shift of the current oscillation signal; transfer function H u ( s ) represents the gain and phase shift of the voltage oscillation signal; F s ( s ) is the transfer function of the band-stop filter; F p ( s ) is the transfer function of the band-pass filter.

[0031] Furthermore, parameter design is carried out for the damping controller, including determining the transfer function of the band-pass filter and the parameter tuning of the proportional phase-shift link, as follows:

[0032] To determine the transfer function of the band-pass filter in the damping controller, the following conditions need to be met: retain the amplitude of the oscillation signal; make the phase of the oscillation signal have no difference; ensure that the selected bandwidth range fits the requirements;

[0033] (41)The band-pass filter consists of a high-pass filter G high ( s ) and a low-pass filter G low ( s ) and its transfer function G band ( s ) is:

[0034]

[0035] Set the phase shifter as a lag network, then the transfer function of the phase shifter G phase(s) is:

[0036]

[0037] Where: α is a coefficient greater than 1, used to adjust the characteristics of the phase shifter; s is the complex frequency variable in the Laplace transform; T is the time constant;

[0038] (42) Configure the phase shifter according to the required phase shift angle and specific frequency:

[0039]

[0040]

[0041] Where: is the maximum lag angle of the lag network; is the frequency of the maximum lag angle; T is the time constant; .

[0042] Furthermore, construct an equivalent RLC circuit for the wind power grid-connected system, complete the design of the phase shift parameter calculation link according to the equivalent impedance size, and construct a complete adaptive damping controller, specifically as follows:

[0043] Set R c and L c represent the parallel impedance of the adaptive damping controller. The adaptive damping controller uses voltage as the feedback signal. In the oscillation frequency range, the wind farm side is equivalent to a negative resistance R w and inductance L w , and the grid side is equivalent to a positive resistance R g and capacitance C g , and the adaptive damping controller is equivalent to a controllable impedance to dynamically optimize the system damping;

[0044] (51) The eigenvalues of the equivalent circuit are expressed as follows:

[0045]

[0046] Where: ;

[0047] Therefore, the real part of the eigenvalue is positive, indicating that the system is unstable, and the imaginary part of the eigenvalue is the oscillation angular frequency;

[0048] (52) At this time, the state matrix of the third-order circuit is:

[0049]

[0050] Adjust the impedance angle and impedance magnitude of the adaptive damping controller , and calculate the real part of the eigenvalue in the oscillation mode;

[0051] Impedance Z c The amplitude is directly related to the gain of the damping control loop, i.e., the device capacity , and the device capacity is designed according to the following formula:

[0052]

[0053] In the formula: I max represents the current amplitude in the case of the maximum oscillation; U rms is the effective voltage value; k m is the margin value;

[0054] Impedance Z c The phase angle of reflects the total phase shift of the damping control loop, and the phase angle is within ;

[0055] The controller uses a second-order lead-lag link to accurately adjust the phase shift, and the transfer function is as follows:

[0056]

[0057] In the formula: T u is the time constant of the phase shift link; s is the complex frequency variable in the Laplace transform; is the gain coefficient, which is used to adjust the response intensity of the system.

[0058] (53) Set the target impedance angle , and the range is within range. According to the oscillation frequency , adaptively adjust the parameter configuration of the phase shift link. The time constant of the phase shift link is adjusted to:

[0059]

[0060] In the formula: is the sum of the phase shifts of the band-pass filter at the oscillation frequency .

[0061] Furthermore, build a simulation model of the wind power grid-connected system and carry out parameter design, specifically as follows:

[0062] (61)The simulation model of the wind power grid-connected system uses a direct-drive wind turbine, which is PWM-controlled by the machine-side converter. After passing through the Boost boost chopper, it is output to the inverter. The grid-side converter uses a dual-loop active and reactive power control to control the current phase-locked loop frequency, and the phase-locked loop frequency controls the current inverter. The three-phase current and three-phase voltage output by the inverter are sent to the grid connection side;

[0063] (62)The parameter design of the simulation model includes the parameters of the core components of the wind power grid-connected system, grid parameters, filter parameters, and control strategy parameters:

[0064] The grid-side converter is an LCL-type filter. The inductances on the converter side and the grid side are set to 4 mH and 0.8 mH respectively, and the parameters of the filter capacitor and its resistance are set to 3 μF and 0.1 Ω; the equivalent inductance value of the shunt compensation grid is 2 mH, and the equivalent resistance value is 0.2 Ω.

[0065] Furthermore, the voltage signal collected by the wind power grid-connected system simulation model is received, and the signal is processed using the fast Fourier transform to identify the oscillation frequency, and it is judged whether there is an unstable oscillation mode in the wind power grid-connected system. If there is an unstable oscillation, an adaptive damping controller is connected between the wind farm side and the grid side, specifically as follows:

[0066] (71)Apply a disturbance to the interaction between the three-phase voltage source and the wind turbine, and observe and analyze the voltage and current changes under the disturbance response;

[0067] (72)Use the fast Fourier transform processing method to identify the oscillation frequency;

[0068] (72.1)Collect the voltage signal data under the disturbance response, and preprocess the collected signal data, including filtering, denoising, and normalization;

[0069] (72.2)Apply the FFT algorithm to the preprocessed signal data to convert the time-domain signal into a frequency-domain signal;

[0070] (72.3)Analyze the FFT result and identify the frequency components with significant amplitudes in the spectrum, which are the oscillation frequencies of the system;

[0071] (72.4)According to the identified oscillation frequency, further analyze the dynamic characteristics and stability of the system;

[0072] (73)For the oscillation situation of the system, build an adaptive damping controller, determine the cut-off frequencies of the high-pass filter and the low-pass filter, and construct a band-pass filter, and complete the input-output test of the band-pass filter.

[0073] Furthermore, it also includes the detection of the oscillation suppression effect, specifically as follows:

[0074] (81) Compare the waveforms of grid-side voltage and current, the total harmonic distortion diagrams of grid-connected voltage and current, and the power waveform diagrams before and after the connection of the contrast adaptive damping controller, and verify whether the power utilization efficiency of the system is improved and whether the negative impacts on the power grid stability and power quality are controlled after the connection of the adaptive damping controller;

[0075] (82) Compare the oscillation suppression effects of the adaptive damping controller on 2MW wind turbines and 1kW wind turbines, and verify that the adaptive damping controller can perform consistent adjustment of the impedance phases of different-capacity units without parameter adjustment;

[0076] (83) Change the grid shunt capacitor conditions and comprehensively evaluate the operating performance of different units under different grid conditions.

[0077] According to the second aspect of the present invention, the present invention provides a wind power grid-connected oscillation suppression system based on an adaptive damping controller, which is used to implement the above-mentioned wind power grid-connected oscillation suppression method based on an adaptive damping controller, including:

[0078] An adaptive damping controller construction module, which is used to construct an adaptive damping controller based on the introduction of an oscillation frequency identification module and a phase shift parameter calculation module in the damping controller structure, analyze the damping characteristics of the wind power grid-connected system, and complete the parameter tuning of the adaptive damping controller;

[0079] A simulation model construction module, which is used to construct a wind power grid-connected system simulation model and perform parameter design;

[0080] A judgment module, which is used to receive the voltage signal collected by the wind power grid-connected system simulation model, process the signal using fast Fourier transform to identify the oscillation frequency, judge whether the wind power grid-connected system has an unstable oscillation mode, and if there is an unstable oscillation, connect the adaptive damping controller between the wind farm side and the grid side;

[0081] An oscillation suppression module, which is used to filter out the signal components that cause the oscillation of the wind power grid-connected system by the adaptive damping controller, and inject them into the grid after phase modulation to cancel the original signal and achieve the suppression of the oscillation.

[0082] According to the third aspect of the present invention, the present invention provides a terminal device, including a memory, a processor, and a computer program stored in the memory and capable of running on the processor. When the processor loads and executes the computer program, the above-mentioned wind power grid-connected oscillation suppression method based on an adaptive damping controller is adopted.

[0083] The present invention has at least the following beneficial effects:

[0084] 1. The adaptive damping controller designed in the present invention can make full use of measurement data by introducing an oscillation frequency identification module and a phase shift parameter calculation module, adjust the parameters of the control link according to the change of vibration frequency, and does not need to know the system model or oscillation frequency in advance.

[0085] 2. The adaptive damping controller designed in the present invention can adapt to the change of the system operating point, realize the adaptive suppression of subsynchronous oscillation, has clear physical meaning and is easy to implement, and is expected to provide a new control device for solving the oscillation problem of the wind power integration system in engineering practice.

[0086] 3. The simulation structure built in the present invention, by constructing a wind power integration system model on the MATLAB / Simulink platform, reproduces the oscillation phenomenon in the actual system, provides a reliable test platform for verifying the effectiveness of the proposed adaptive damping controller, and shows significant beneficial effects in accurately reproducing the oscillation phenomenon, efficiently verifying the control strategy, adapting to various grid states, comparing and evaluating performance advantages, and reducing R & D costs and risks, and has important practical application value and broad development prospects for solving the oscillation problem in the wind power integration system.

[0087] Of course, it is not necessary for any product implementing the present invention to achieve all the above-mentioned advantages simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] Figure 1 is a schematic flow chart of the suppression method described in the present invention;

[0089] Figure 2 is a schematic diagram of the composition principle of the adaptive damping controller of the present invention;

[0090] Figure 3 is a schematic diagram of the working principle of the damping calculator of the present invention;

[0091] Figure 4 is a design structure diagram of the damping controller of the present invention;

[0092] Figure 5 is a design structure diagram of the adaptive damping controller of the present invention;

[0093] Figure 6 is an equivalent circuit diagram of RLC of the present invention;

[0094] Figure 7 is the real part of the eigenvalue of the system after connecting the parallel adaptive damping controller of the present invention;

[0095] Figure 8 is a topological structure diagram of the wind power integration system of the present invention;

[0096] Figure 9 is Figure 8 an enlarged structure diagram of the area at point A in

[0097] Figure 10 For Figure 8 Enlarged view of the structure of area B in

[0098] Figure 11 It is the Bode plot of the wind power grid - connected system under the disturbance of the present invention at 1 - 1000 Hz;

[0099] Figure 12 It is the Bode plot of the wind power grid - connected system under the disturbance of the present invention at 40 - 60 Hz;

[0100] Figure 13 It is the Bode plot of the band - pass filter of the present invention;

[0101] Figure 14 It is the waveform diagram of the grid - side voltage and current when the adaptive damping controller is not connected in the present invention;

[0102] Figure 15 It is the waveform diagram of the grid - side voltage and current when the adaptive damping controller is connected in the present invention;

[0103] Figure 16 It is the total harmonic distortion value of the grid - connected current when the adaptive damping controller is not connected in the present invention;

[0104] Figure 17 It is the total harmonic distortion value of the grid - connected current when the adaptive damping controller is connected in the present invention;

[0105] Figure 18 It is the power factor waveform diagram when the adaptive damping controller is not connected in the present invention;

[0106] Figure 19 It is the active power waveform diagram when the adaptive damping controller is connected in the present invention;

[0107] Figure 20 It is the reactive power waveform diagram when the adaptive damping controller is connected in the present invention;

[0108] Figure 21 It is the oscillation suppression effect diagram for the 2MW wind turbine of the present invention;

[0109] Figure 22 It is the oscillation suppression effect diagram for the 1kW wind turbine of the present invention. Detailed implementation manners

[0110] Next, the technical solutions in the embodiments of the present disclosure will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present disclosure.

[0111] Example 1:

[0112] Please refer to Figure 1 , the present invention provides a technical solution: a method for suppressing wind power grid connection oscillation based on an adaptive damping controller, including the following steps:

[0113] S1. Introduce an oscillation frequency identification module and a phase shift parameter calculation module into the damping controller structure to construct an adaptive damping controller, analyze the damping characteristics of the wind power grid connection system, and complete the parameter tuning of the adaptive damping controller;

[0114] During the oscillation of the system, the adaptive damping controller can realize the adaptive modification of parameters and output a suppression current signal. The specific design steps of the adaptive damping controller include:

[0115] S11 Analyze the damping characteristics of the wind power grid connection system to obtain the oscillation suppression mechanism for the access of the damping controller;

[0116] The adaptive damping controller is an oscillation suppression device installed on the grid side of the wind farm collecting bus. The adaptive damping controller is equivalent to a controllable impedance with the bus voltage of the electric field u and line current i as feedback signals; identify the oscillation frequency based on the FFT signal processing method, obtain the oscillation mode damping , generate three-phase current and inject it into the grid by accessing the adaptive damping controller, so as to adjust the damping characteristics of the system at the oscillation frequency point to achieve wide-frequency oscillation suppression; the composition principle of the adaptive damping controller is as Figure 2 shown. Taking the wind farm as an example, the equivalent impedance Z W on the wind farm side includes the total impedance Z WTG of the wind turbines, the transformer impedance Z T and the line impedance Z NL , and the equivalent impedance Z N on the grid side includes the line impedance Z CL and the total impedance Z SYS of the receiving system;

[0117] When the adaptive damping controller is not connected to the system, the total impedance of the system can be expressed as Z Σ = Z W +Z N； At the oscillation frequency If the downwind power farm exhibits negative resistance, broadband oscillation may occur;

[0118] After the adaptive damping controller is connected to the system, the total impedance of the system is:

[0119]

[0120] In the formula: Z W is the equivalent impedance on the wind farm side; Z N is the equivalent impedance on the grid side; H i and H u are the transfer functions of the current feedback signal i and the voltage feedback signal u respectively;

[0121] By introducing the adaptive damping controller, the impedance characteristic of the system at the oscillation frequency is adjusted, so that changes from a positive value to a negative value, thereby effectively suppressing broadband oscillation;

[0122] S12, design the structure of the damper calculator (DC), including a band-stop filter, a band-pass filter, a proportional phase-shifting link, and a limiting link, and generate a reference signal for suppressing broadband oscillation from the feedback signal;

[0123] DC can obtain a suitable reference signal through the frequency components in the feedback signal. The overall structure includes signal extraction, proportional phase-shifting, and an adder. As Figure 3 shown, first, use the band-stop filter F s ( s ) and the band-pass filter F p ( s ) to filter the power frequency components in the feedback signal to achieve signal extraction. Then, use the proportional phase-shifting link to process the signal and synthesize the required current reference signal through the adder. The relationship between the output and input signals of DC is:

[0124]

[0125] In the formula: ; represents the gain of the current frequency signal; represents the phase shift of the current frequency signal; ; Represents the gain of the voltage-frequency signal; Represents the phase shift of the voltage-frequency signal, i Represents the current input signal; u Represents the voltage input signal; Transfer function H i ( s ) Represents the gain and phase shift of the current oscillation signal; Transfer function H u ( s ) Represents the gain and phase shift of the voltage oscillation signal; F s ( s ) Is the transfer function of the band-stop filter; F p ( s ) Is the transfer function of the band-pass filter;

[0126] S13, Design the current generator (CG) structure. The CG receives the reference signal provided by the DC, precisely controls the generation of three-phase current through the converter, and injects it into the power grid;

[0127] The current reference signal generated by the DC is transmitted into the CG through optical fiber communication. Subsequently, the CG converts the current reference signal into the current injected into the power grid; The CG consists of a cascaded converter, a controller, and a boost transformer. Its main function is to convert the received reference signal into the modulation wave signal required by the cascaded converter; In addition, the selection of the connecting reactance and DC capacitor is crucial for the components of the cascaded converter to ensure that the system has sufficient response speed and minimizes DC voltage fluctuations;

[0128] S14, Based on the damping controller, dynamically monitor the current signal through the oscillation frequency identification module, accurately capture the oscillation frequency in the power grid, and then use it for the phase shift parameter calculation module to dynamically adjust the time constant of the controller and achieve adaptive adjustment of the proportional phase shift link;

[0129] The damping controller consists of the DC and the CG, as Figure 4 shown; In the structure of the adaptive damping controller, based on the design of the damping controller, an oscillation frequency identification module and a phase shift parameter calculation module are introduced. Among them, the oscillation frequency identification uses the FFT module;

[0130] Compared with the traditional fixed-parameter damping controller, the adaptive damping controller has the ability to identify the change of oscillation frequency in real time and can dynamically adjust the control parameters according to the identification result to ensure the stability of the system; Figure 5 Is the basic architecture of the adaptive damping controller, the DC voltage given value U dc_ref Is the input signal, through the proportional gain of the outer loopK p_out With integral gain K i_out Calculate the grid side d Shaft current set value I gd_ref , and the grid side d Shaft current component I gd Compare and filter out oscillation signals i abc ; U dc The input signal of the adaptive damping controller is first filtered out by a filter to remove the signal component that causes the system oscillation. Then the signal is precisely phase-adjusted through a proportional phase shift link to ensure that it is synchronized with the system oscillation frequency. Then it is injected into the power grid to offset the original oscillation signal and complete the oscillation suppression process;

[0131] S15, performing parameter design on the damping controller, mainly including determining the transfer function of the filter and parameter setting of the proportional phase shift link;

[0132] To determine the transfer function of the filter in the damping controller, the following conditions need to be met: the amplitude of the oscillation signal should be retained as much as possible; the phase of the oscillation signal should be indistinguishable; and the selected bandwidth range should be consistent with the requirements;

[0133] Bandpass filter by high pass filter G high ( s ) and low pass filter G low ( s ) is composed of two components, and its transfer function G band ( s )for:

[0134]

[0135] Assuming the phase shifter is a lag network, the transfer function of the phase shifter is G phase (s) is:

[0136]

[0137] Where: α is a coefficient greater than 1, which is used to adjust the characteristics of the phase shifter, thereby affecting the phase response of the system; s is the complex frequency variable in Laplace transform; T is the time constant;

[0138] Furthermore, the phase shifter is configured according to the desired phase shift angle and specific frequency:

[0139]

[0140]

[0141] In the formula: is the maximum lag angle of the lag network; is the frequency of the maximum lag angle; T is the time constant; ;

[0142] S16, considering the magnitude of the equivalent impedance of the suppression device (adaptive damping controller), and completing the design of the phase shift parameter calculation link, to construct a complete adaptive damping controller;

[0143] Construct an equivalent RLC circuit of the system, as Figure 6 shown; where R c and L c represent the parallel impedance of the suppression device, which uses the voltage as the feedback signal. In the oscillation frequency range, the wind farm side is equivalent to a negative resistance R w and the inductor L w , the grid side is equivalent to a positive resistance R g and the capacitor C g , the suppression device is equivalent to a controllable impedance to dynamically optimize the system damping;

[0144] The eigenvalues of the equivalent circuit are expressed as follows:

[0145]

[0146] In the formula: ;

[0147] Therefore, the real part of the eigenvalue is positive, indicating that the system is unstable, and the imaginary part of the eigenvalue is the oscillation angular frequency;

[0148] To improve the system performance, after connecting the parallel suppression device, the state matrix of the third-order circuit is:

[0149]

[0150] As Figure 7 shown, adjust the impedance angle and magnitude of the suppression device , and calculate the real part of the eigenvalue in the oscillation mode;

[0151] The impedance Z c is directly related to the gain of the damping control loop, that is, the capacity of the device, as Figure 7As shown, the increase in gain leads to an increase in output current and a decrease in impedance value, thereby enhancing the oscillation suppression effect. In engineering practice, economic cost factors also need to be considered comprehensively. The design of the device capacity can be based on the following formula:

[0152]

[0153] In the formula: I max represents the current amplitude in the most severe oscillation case; U rms is the effective value of voltage; k m is the margin value;

[0154] The impedance Z c The phase angle of reflects the total phase shift of the damping control loop, and it can be seen from Figure 7 that when the phase angle is in the range, the controller can effectively ensure that the real part of the eigenvalue is negative and maintain the system stability;

[0155] To achieve this goal, the controller uses a second-order lead-lag link to accurately adjust the phase shift, and the transfer function is as follows:

[0156]

[0157] In the formula, T u is the time constant of the phase shift link; s is the complex frequency variable in the Laplace transform; is the gain coefficient, which is used to adjust the response intensity of the system;

[0158] Although it is difficult to directly construct an equivalent circuit model of the system in practical applications, a target impedance angle can be initially set, and its range is defined within range. Then, based on the oscillation frequency obtained by FFT, the parameter configuration of the phase shift link is adaptively adjusted to ensure that the total phase shift remains consistent at different oscillation frequencies. The time constant of the phase shift link is adjusted to:

[0159]

[0160] In the formula: is Figure 5 the sum of the phase shifts of the band-pass filter in at the oscillation frequency;

[0161] S2. Build a simulation model of the wind power grid-connected system and carry out parameter design;

[0162] Figure 8Shows an oscillation suppression model of a wind power grid-connected system based on an adaptive damping controller. Figure 9 is Figure 8 an enlarged view of the structure of area A in Figure 10 is Figure 8 an enlarged view of the structure of area B in

[0163] The grid-side converter adopts a double closed-loop control strategy, constructs an outer voltage control loop and an inner current control loop, and adds a limiting link before the current control loop to control the active power and reactive power respectively, and controls the PWM signal of the inverter through a phase-locked loop (PLL) to ensure that the output current is synchronized with the grid voltage; the inverter converts direct current into three-phase alternating current compatible with the grid and outputs it to the grid; the adaptive damping controller in the system is used to monitor and suppress the oscillation on the grid side. In the power transmission control mode, the grid-side converter selects an LCL-type filter; the inductances on the converter side and the grid side are set to 4 mH and 0.8 mH respectively to adapt to different current transmission requirements. At the same time, the parameters of the filter capacitor and its resistor are set to 3 μF and 0.1 Ω. In the grid simulation, the equivalent inductance value of the shunt capacitor grid is measured to be 2 mH, and the equivalent resistance value is 0.2 Ω.

[0164] S3 receives the voltage signal collected by the wind power grid-connected system simulation model, uses the fast Fourier transform to process the signal to identify the oscillation frequency, and judges whether there is an unstable oscillation mode in the wind power grid-connected system. If there is an unstable oscillation, an adaptive damping controller is connected between the wind farm side and the grid side;

[0165] To further simplify the calculation, it is first assumed that all wind turbines are operating under the same working conditions and they belong to the same model. The specific steps of the system stability analysis and oscillation signal extraction process include:

[0166] S31 applies a disturbance to the interaction between the three-phase voltage source and the wind turbine, and then observes and analyzes the voltage and current changes under the disturbance response;

[0167] The methods to simulate the actual oscillation phenomenon include: quickly reducing the output of the fan, changing the phase-locked loop parameters to cause power over-limit, and quickly increasing the load;

[0168] Observe the grid-side voltage and current waveforms when the oscillation occurs, the total harmonic distortion comparison chart of the grid-connected voltage and current, and the power factor waveform chart without connecting the suppression device;

[0169] S32 identifies the oscillation frequency based on the signal processing method of the fast Fourier transform (FFT);

[0170] Collect the voltage signal data under disturbance response; preprocess the collected signal data, including filtering, denoising, and normalization, to improve the accuracy of FFT analysis; apply the FFT algorithm to the preprocessed signal data to convert the time-domain signal into a frequency-domain signal; analyze the FFT results to identify the frequency components with significant amplitudes in the spectrum, and these frequency components are the oscillation frequencies of the system; further analyze the dynamic characteristics and stability of the system based on the identified oscillation frequencies

[0171] When the suppression device is not installed, Figure 11 is the Bode diagram of the wind power grid-connected system at 1 - 1000 Hz under the disturbance of the present invention; Figure 12 is the Bode diagram of the wind power grid-connected system at 40 - 60 Hz under the disturbance of the present invention; the phase angle difference between the wind turbine and the HVDC transmission system at 45 Hz is 181.6°, and the phase angle differences between the wind turbines and the HVDC transmission system outside the domain are all less than 180° below 45 Hz. That is, the phase angle difference crosses 180° once in the left domain of 45 Hz. Therefore, this system has an oscillation risk;

[0172] After detecting that the system exhibits an oscillation behavior of 45 Hz, according to dq the frequency shift characteristic of the transformation, in αβ the 45 Hz signal in the coordinate system is transformed by dq and converted into a 5 Hz signal. Therefore, by suppressing the 5 Hz oscillation signal in U dc the machine terminal oscillation can be suppressed;

[0173] S33. For the oscillation situation of the system, build an adaptive damping controller, determine the cut-off frequencies of the high-pass filter and the low-pass filter, and construct a band-pass filter, and complete the input-output test of the band-pass filter;

[0174] After testing, a band-pass filter is constructed using a high-pass filter with a cut-off frequency of 2 Hz and a low-pass filter with a cut-off frequency of 12 Hz;

[0175] The transfer function of the band-pass filter ; As Figure 13 shown, conduct the input-output test on the band-pass filter. The amplitude of the oscillation signal is retained as much as possible at 5 Hz, and the phase angle here is 0.277°, with almost no phase difference, effectively ensuring the extraction of the oscillation signal;

[0176] S4. The adaptive damping controller filters out the signal components causing system oscillation, performs phase modulation, and then injects them into the power grid to cancel the original signal, achieving oscillation suppression;

[0177] The specific steps for detecting the oscillation suppression effect include:

[0178] S41. Compare the grid-side voltage and current waveforms, the total harmonic distortion diagrams of the grid-connected voltage and current, and the power waveform diagrams before and after the adaptive damping controller is connected. Verify that after the adaptive damping controller is connected, the power utilization efficiency of the system has been significantly improved, and the negative impacts on the stability of the power grid and the power quality have been effectively controlled;

[0179] S42. Compare the oscillation suppression effects of the adaptive damping controller on 2MW wind turbines and 1kW wind turbines. Verify that without parameter adjustment, the controller can uniformly adjust the impedance phases of different-capacity units, ensuring the unity and reliability of the control effect;

[0180] S43. Change the grid shunt capacitor conditions and comprehensively evaluate the operating performance of different units under different grid conditions to verify the grid adaptability of the strategy.

[0181] Next, the technical solution of the present invention will be further elaborated in combination with specific embodiments:

[0182] Based on the above solution, in this embodiment, the above method is applied as an example, specifically as follows:

[0183] As Figures 8 to 10 shown, in the construction of the wind power grid-connected system, core components such as direct-drive wind turbines, three-phase two-level back-to-back converters, and transformers are integrated, and key elements such as a simulated grid power supply and a simulated grid impedance are introduced; among them, the grid impedance includes a series resistive-inductive line and a shunt capacitor. The grid and wind turbine parameters are shown in Table 1:

[0184] Table 1 1kW grid-connected wind turbine parameters

[0185]

[0186] Case Result 1: Oscillation suppression effect before and after connecting the adaptive damping controller

[0187] Figure 14 is the grid-side voltage and current waveform diagram when the adaptive damping controller of the present invention is not connected; Figure 15 is the grid-side voltage and current waveform diagram when the adaptive damping controller of the present invention is connected. Set the active power to 1kW, the reactive power to 0Var, the rotational speed to 800r / min, and the grid shunt capacitor to 30μF. As Figure 15 shown, by introducing the adaptive damping controller, the oscillation state of the system has been effectively controlled, ensuring the stable operation of the system. When the adaptive damping controller is put into operation, the grid-connected voltage and current of the system both show smooth sine wave forms.

[0188] Under the current operating conditions, the total harmonic distortion (THD) value of the grid-connected current is significantly reduced from 27.62% to 1.7%, achieving efficient suppression of system oscillations. Figure 16 is the total harmonic distortion value of the grid-connected current when the adaptive damping controller of the present invention is not connected. Figure 17 is the total harmonic distortion value of the grid-connected current when the adaptive damping controller of the present invention is connected.

[0189] The positive impact brought by the adaptive damping controller can also be clearly observed from the power perspective. For example, Figure 18 as shown, when the adaptive damping controller is not connected, the power factor is close to -1, indicating that the system mainly emits reactive power, which has an adverse impact on the stability of the power grid and the power quality.

[0190] Figure 19 is the active power waveform diagram when the adaptive damping controller of the present invention is connected. Figure 20 is the reactive power waveform diagram when the adaptive damping controller of the present invention is connected. After connecting the adaptive damping controller, significant changes have occurred in the experimental results. The reactive power has been significantly reduced and approaches 0, while the active power remains stable. This indicates that the electrical energy generated by the system is closer to the actual required active power, reducing the waste of reactive power, significantly improving the electrical energy utilization efficiency of the system, and effectively controlling the negative impact on the stability of the power grid and the power quality.

[0191] Case Result Two: Oscillation Suppression Effect of the Adaptive Damping Controller on Wind Turbines with Different Capacities

[0192] Figure 21 and Figure 22 show the oscillation suppression effects of the adaptive damping controller on 2MW and 1kW wind turbines in the high-frequency range. The output impedance Z GS before adjustment and becomes Z GS_re after adjustment. By observing the changes in the curves, the following conclusions can be obtained:

[0193] 1) The adaptive damping controller proposed in this embodiment can effectively adjust the phase of the unit output impedance: for the 2MW unit, the controller optimizes the phase difference between the impedance of the grid-side converter and the grid impedance, achieving a phase adjustment from 173° to 125°. Similarly, for the 1kW unit, the oscillation suppressor adjusts the phase difference to 121°.

[0194] 2) The adaptive damping controller has high versatility: without parameter adjustment, the controller can uniformly adjust the impedance phase of units with different capacities, ensuring the unity and reliability of the control effect.

[0195] Case Result 3: Changing the shunt capacitor conditions of the power grid comprehensively evaluates the operating performance under different power grid states

[0196] Figure 21 For a 2MW unit, when the shunt compensation degree changes from 2.7 μF to 4.5 μF, the intersection point of the impedance amplitude shifts to P 1 and P 2, and the impedance phase differences are 45° and 141° respectively; Figure 22 For a 1kW unit, when the shunt compensation degree changes from 12 μF to 30 μF, the shift of the amplitude intersection point to P 3 and P 4 is also observed, and the impedance phase differences are 46° and 130° respectively; it is concluded that this suppression strategy can adapt to different shunt capacitor conditions of the power grid, and can maintain a stable impedance adjustment effect even when the controlled object changes.

[0197] Example 2:

[0198] The present invention provides a wind power grid connection oscillation suppression system based on an adaptive damping controller, which is used to implement the above-mentioned wind power grid connection oscillation suppression method based on an adaptive damping controller, and includes:

[0199] An adaptive damping controller construction module, which is used to construct an adaptive damping controller based on introducing an oscillation frequency identification module and a phase shift parameter calculation module in the damping controller structure, analyze the damping characteristics of the wind power grid connection system, and complete the parameter tuning of the adaptive damping controller;

[0200] A simulation model construction module, which is used to construct a wind power grid connection system simulation model and carry out parameter design;

[0201] A judgment module, which is used to receive the voltage signal collected by the wind power grid connection system simulation model, use the fast Fourier transform to process the signal to identify the oscillation frequency, judge whether the wind power grid connection system has an unstable oscillation mode, and if there is an unstable oscillation, connect an adaptive damping controller between the wind farm side and the power grid side;

[0202] An oscillation suppression module, which is used to filter out the signal components that cause the oscillation of the wind power grid connection system by the adaptive damping controller, and after phase modulation, inject them into the power grid to cancel out with the original signal, so as to achieve the suppression of the oscillation.

[0203] Example 3:

[0204] According to the third aspect of the present invention, the present invention provides a terminal device, including a memory, a processor, and a computer program stored in the memory and capable of running on the processor. When the processor loads and executes the computer program, the above-mentioned wind power grid connection oscillation suppression method based on an adaptive damping controller is adopted.

[0205] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device.

[0206] For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. When an element is referred to as being "assembled on", "mounted on", "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0207] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

[0208] In the description of this specification, the description with reference to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

Claims

1. A method for suppressing wind power grid connection oscillation based on an adaptive damping controller, characterized in that, It includes the following steps: Based on the introduction of an oscillation frequency identification module and a phase shift parameter calculation module in the damping controller structure, an adaptive damping controller is constructed to analyze the damping characteristics of the wind power grid-connected system and complete the parameter tuning of the adaptive damping controller; Construct a simulation model of the wind power grid-connected system and conduct parameter design; Receive the voltage signal collected by the simulation model of the wind power grid-connected system, use the fast Fourier transform to process the signal to identify the oscillation frequency, and determine whether there is an unstable oscillation mode in the wind power grid-connected system. If there is an unstable oscillation, connect the adaptive damping controller between the wind farm side and the grid side; The adaptive damping controller filters out the signal components that cause the oscillation of the wind power grid-connected system, and after phase modulation, injects them into the grid to cancel the original signal and achieve the suppression of the oscillation; The adaptive damping controller is equivalent to a controllable impedance with the bus voltage u of the electric field and the line current i as feedback signals. Based on the FFT signal processing method, the oscillation frequency is identified, the damping of the oscillation mode is obtained, and by connecting the adaptive damping controller, three-phase current is generated and injected into the grid, so as to adjust the damping characteristics of the system at the oscillation frequency point to achieve wide-frequency oscillation suppression; After the adaptive damping controller is connected to the system, the total impedance of the system is as follows: In the formula: ZW is the equivalent impedance on the wind farm side; ZN is the equivalent impedance on the grid side; Hi and Hu are the transfer functions of the current feedback signal i and the voltage feedback signal u respectively; Design the structure of the damping calculator, which specifically includes a band-stop filter, a band-pass filter, a proportional phase shift link, and a limiter. Use the damping calculator to generate a reference signal for suppressing wide-frequency oscillation according to the feedback signal; Design the structure of the current generator, which specifically includes a cascaded converter, a controller, and a step-up transformer. The current generator receives the reference signal provided by the damping calculator, controls the generation of three-phase current through the converter, and injects it into the grid; Based on the damping controller, the oscillation frequency identification module dynamically monitors the current signal to capture the oscillation frequency in the grid, and then uses it for the phase shift parameter calculation module to dynamically adjust the time constant of the controller to achieve the adaptive adjustment of the proportional phase shift link. Specifically as follows: The DC voltage set value Udc_ref is used as the input signal, and the grid-side d-axis current set value Igd_ref is calculated through the proportional gain Kp_out and the integral gain Ki_out of the outer loop. Compare it with the grid-side d-axis current component Igd to filter out the oscillation signal iabc; Udc is the input signal of the adaptive damping controller. First, the signal components that cause system oscillation are filtered out by a band-pass filter. Subsequently, the signal is subjected to precise phase adjustment through a proportional phase-shifting link to ensure its synchronization with the system oscillation frequency, obtaining and then injected into the power grid to cancel out the original oscillation signal, completing the oscillation suppression process; Conduct parameter design for the damping controller, including determining the transfer function of the band-pass filter and the parameter tuning of the proportional phase shift link; Construct an equivalent RLC circuit of the wind power grid-connected system, complete the design of the phase shift parameter calculation link according to the size of the equivalent impedance, and construct a complete adaptive damping controller.

2. The wind power grid connection oscillation suppression method based on an adaptive damping controller according to claim 1, wherein Use the damping calculator to generate a reference signal for suppressing wide-frequency oscillation according to the feedback signal. Specifically as follows: The power frequency component in the feedback signal is filtered by a band-stop filter and a band-pass filter to extract the signal. Then, the signal is processed by a proportional phase-shifting section, and the required current reference signal is synthesized by an adder. ; The relationship between the output and input signals of the damping calculator is: Wherein: i represents a current input signal; u represents the voltage input signal; represents the gain of the current frequency signal; represents the phase shift of the current frequency signal; represents the gain of the voltage frequency signal; represents the phase shift of the voltage frequency signal; Transfer function H i ( s ) represents the gain and phase shift of the current oscillation signal; Transfer function H u ( s ) represents the gain and phase shift of the voltage oscillation signal; F s ( s ) is the transfer function of the band-stop filter; F p ( s ) is the transfer function of the band-pass filter.

3. The method for suppressing wind power grid connection oscillation based on an adaptive damping controller according to claim 2, wherein: Conduct parameter design for the damping controller, including determining the transfer function of the band-pass filter and the parameter tuning of the proportional phase shift link. Specifically as follows: To determine the transfer function of the band-pass filter in the damping controller, the following conditions need to be met: preserve the amplitude of the oscillating signal; make the phase of the oscillating signal have no difference; ensure that the selected bandwidth range matches the requirements; The band - pass filter consists of a high - pass filter G high ( s ) and a low - pass filter G low ( s ). Its transfer function G band ( s ) is as follows: Set the phase shifter as a lag network, then the transfer function of the phase shifter G phase (s) is: Wherein: α is a coefficient greater than 1 for adjusting the characteristics of the phase shifter; s is the complex frequency variable in the Laplace transform; T is the time constant; Configure the phase shifter according to the required phase shift angle and specific frequency: Wherein: is the maximum lag angle of the lag network; is the frequency of the maximum lag angle; T is the time constant; .

4. The method for suppressing wind power grid connection oscillation based on an adaptive damping controller according to claim 3, characterized in that: Construct an equivalent RLC circuit for the wind power grid-connected system, complete the design of the phase shift parameter calculation link according to the equivalent impedance size, and construct a complete adaptive damping controller, as follows: Settings R c and L c represent the shunt impedance of the adaptive damping controller. The adaptive damping controller uses voltage as the feedback signal. In the oscillation frequency range, the wind farm side is equivalent to a negative resistor. R w and inductance L w , and the grid side is equivalent to a positive resistor. R g and capacitance C g , and the adaptive damping controller is equivalent to a controllable impedance to dynamically optimize the system damping; The eigenvalues of the equivalent circuit are expressed as follows: In the formula: ; Therefore, the real part of the eigenvalue is positive, indicating that the system is unstable, and the imaginary part of the eigenvalue is the oscillation angular frequency; At this time, the state matrix of the third-order circuit is: Adjust the impedance angle and impedance magnitude of the adaptive damping controller , and calculate the real part of the eigenvalue in the oscillation mode; Impedance Z c The amplitude value of which is directly related to the gain of the damping control loop, i.e., the device capacity , and the device capacity is designed according to the following formula: In the formula: I max represents the current amplitude under the maximum oscillation condition; U rms is the effective voltage value; k m is the margin value; Impedance Z c The phase angle of ; The controller uses a second-order lead-lag link to precisely adjust the phase shift, and the transfer function is as follows: Wherein: T u is the time constant of the phase-shifting link; s is the complex frequency variable in the Laplace transform; is the gain coefficient, used to adjust the response intensity of the system; (53)Set the target impedance angle , within the range of , adaptively adjust the parameter configuration of the phase-shifting link according to the oscillation frequency . The time constant of the phase-shifting link is adjusted to: In the formula: is the sum of the phase shifts of the band-pass filter at the oscillation frequency below.

5. The method for suppressing wind power grid connection oscillation based on an adaptive damping controller according to claim 4, wherein Construct a simulation model of the wind power grid-connected system and carry out parameter design, as follows: The simulation model of the wind power grid-connected system uses a direct-drive wind turbine, performs PWM control through the machine-side converter, and after passing through the Boost boost chopper, outputs to the inverter. The grid-side converter uses a double-loop active and reactive power control to control the current phase-locked loop frequency, and the phase-locked loop frequency controls the current inverter. The three-phase current and three-phase voltage output by the inverter to the grid-connected side; The simulation model parameter design includes the core component parameters, grid parameters, filter parameters, and control strategy parameters of the wind power grid-connected system: The grid-side converter is an LCL-type filter. The inductances on the converter side and the grid side are set to 4 mH and 0.8 mH respectively, and the parameters of the filter capacitor and its resistance are set to 3 μF and 0.1 Ω; the equivalent inductance value of the shunt compensation grid is 2 mH, and the equivalent resistance value is 0.2 Ω.

6. The method for suppressing wind power grid connection oscillation based on an adaptive damping controller according to claim 5, wherein: Receive the voltage signal collected by the simulation model of the wind power grid-connected system, use the fast Fourier transform to process the signal to identify the oscillation frequency, and judge whether there is an unstable oscillation mode in the wind power grid-connected system. If there is an unstable oscillation, connect an adaptive damping controller between the wind farm side and the grid side, as follows: Apply a disturbance to the interaction between the three-phase voltage source and the wind turbine, and observe and analyze the voltage and current changes under the disturbance response; Use the fast Fourier transform processing method to identify the oscillation frequency; Collect the voltage signal data under the disturbance response, and preprocess the collected signal data, including filtering, denoising, and normalization; Apply the FFT algorithm to the preprocessed signal data to convert the time-domain signal into a frequency-domain signal; Analyze the FFT result and identify the frequency components with significant amplitudes in the spectrum, which are the oscillation frequencies of the system; According to the identified oscillation frequency, further analyze the dynamic characteristics and stability of the system; For the oscillation situation of the system, build an adaptive damping controller, determine the cut-off frequencies of the high-pass filter and the low-pass filter, and construct a band-pass filter, and complete the input-output test of the band-pass filter.

7. The method for suppressing wind power grid connection oscillation based on an adaptive damping controller according to claim 6, wherein: It also includes the detection of the oscillation suppression effect, as follows: Compare the waveforms of the grid-side voltage and current, the total harmonic distortion diagrams of the grid-connected voltage and current, and the power waveform diagrams before and after the connection of the adaptive damping controller, and verify whether the power utilization efficiency of the system is improved and whether the negative impacts on the stability and power quality of the grid are controlled after the connection of the adaptive damping controller; Compare the oscillation suppression effects of the adaptive damping controller on 2MW and 1kW wind turbines, and verify that the adaptive damping controller can adjust the impedance phase of different capacity units consistently without parameter adjustment; Change the conditions of shunt capacitors in the power grid and comprehensively evaluate the operating performance of different units under different grid states.

8. A wind power grid-connected oscillation suppression system based on an adaptive damping controller, which is used to implement the wind power grid-connected oscillation suppression method based on an adaptive damping controller according to any one of claims 1 to 7, and is characterized in that, Including: An adaptive damping controller construction module, which is used to construct an adaptive damping controller based on the introduction of an oscillation frequency identification module and a phase shift parameter calculation module in the damping controller structure, analyze the damping characteristics of the wind power grid-connected system and complete the parameter tuning of the adaptive damping controller; A simulation model construction module, which is used to construct a wind power grid-connected system simulation model and carry out parameter design; A judgment module, which is used to receive the voltage signal collected by the wind power grid-connected system simulation model, process the signal using fast Fourier transform to identify the oscillation frequency, judge whether there is an unstable oscillation mode in the wind power grid-connected system, and if there is an unstable oscillation, connect an adaptive damping controller between the wind farm side and the grid side; An oscillation suppression module, which is used to filter out the signal components that cause the oscillation of the wind power grid-connected system by the adaptive damping controller, and inject them into the grid after phase modulation to cancel the original signal and achieve the suppression of the oscillation.

9. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and capable of running on the processor, characterized in that, When the processor loads and executes the computer program, it adopts the wind power grid-connected oscillation suppression method based on the adaptive damping controller described in any one of claims 1 to 7.

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