Method and apparatus for suppressing self-correcting wideband oscillations

Abstract

The application relates to the technical field of power system operation and stability control, in particular to a self-correcting wide-frequency oscillation suppression method and device, wherein the method comprises the following steps: extracting a frequency mode corresponding to a control input quantity of a wide-frequency filter, and determining a to-be-suppressed oscillation frequency component according to the frequency mode; generating a first correction function according to the amplitude-phase characteristics of a transfer function of the wide-frequency filter, and generating a second correction function according to the response characteristics of a power electronic converter to the oscillation frequency; determining a design equivalent impedance or admittance control parameter according to the control input quantity, and controlling the to-be-suppressed oscillation frequency component in combination with the first correction function, the second correction function and the equivalent impedance or admittance control parameter, so that the problem that the existing suppression method cannot realize comprehensive adaptation to wide-frequency oscillation characteristics, and cannot continuously and stably exert the suppression effect under full-frequency, variable-frequency and multiple working conditions, and the adaptation scene has limitations, is solved.

Description

Technical Field

[0001] This application relates to the field of power system operation and stability control technology, and in particular to a method and apparatus for suppressing self-correcting broadband oscillations. Background Technology

[0002] With the power system's "high-voltage and high-efficiency" characteristics becoming increasingly prominent, the proportion of converter interfaced generation (CIG), represented by wind power and photovoltaics, in the power structure is gradually increasing. This generation mode is profoundly changing the physical characteristics and stability mechanism of the power system. Due to the fluctuating characteristics of wind and solar resources and the multi-timescale dynamics caused by the high proportion of power electronic equipment, broadband oscillation has become a prominent stability problem faced by the new power system.

[0003] In related technologies, given the characteristics of wide-bandwidth oscillations, such as wide frequency range, time-varying risk frequencies, and strong dependence on operating conditions, many scholars have proposed oscillation suppression methods and strategies that can adapt to changes in operating conditions and target frequencies. For example, in grid-connected inverters, active disturbance rejection control is introduced to replace the existing proportional-integral control, which estimates and compensates for subsynchronous disturbances in real time and has good robustness to changes in operating conditions. Another example is the model-free adaptive control strategy proposed based on a data-driven perspective, which breaks through the limitations of existing control methods that rely on modeling.

[0004] However, the above-mentioned technical solutions all lack the ability to adapt to the broad spectrum for broadband oscillations. Broadband oscillations have the core characteristics of wide frequency range, time-varying risk frequency and strong dependence on operating conditions. Existing suppression methods have not achieved full adaptation to these characteristics and are difficult to exert a continuous and stable suppression effect under full frequency range, variable frequency and multiple operating conditions. The applicable scenarios are limited. Summary of the Invention

[0005] This application provides a self-correcting broadband oscillation suppression method and apparatus to solve the problems of existing suppression methods, which are difficult to achieve a continuous and stable suppression effect across the entire frequency band, variable frequency, and multiple operating conditions, and have limited applicability due to the lack of comprehensive adaptation to broadband oscillation characteristics.

[0006] The first aspect of this application provides a method for suppressing self-calibrated broadband oscillations, comprising the following steps: extracting frequency modes corresponding to the control input of a broadband filter, and determining the oscillation frequency component to be suppressed based on the frequency modes; generating a first correction function based on the amplitude and phase characteristics of the transfer function of the broadband filter, and generating a second correction function based on the response characteristics of the power electronic converter to the oscillation frequency; determining a design equivalent impedance or admittance control parameter based on the control input, and controlling the suppression of the oscillation frequency component by combining the first correction function, the second correction function, and the equivalent impedance or admittance control parameter.

[0007] Through the above-mentioned technical means, the embodiments of this application can first extract the frequency mode corresponding to the control input of the broadband filter, and then determine the oscillation frequency component to be suppressed; then generate the first and second correction functions based on the amplitude and phase characteristics of the broadband filter transfer function and the response characteristics of the power electronic converter to the oscillation frequency; finally, determine the design equivalent impedance or admittance control parameters based on the control input, and combine the two types of correction functions with the impedance / admittance control parameters. The established self-correcting control structure can adapt to a wide frequency range and effectively suppress low-frequency oscillations, sub- / super-synchronous oscillations, near-power frequency oscillations, and medium / high frequency oscillations, and can achieve precise suppression control of the target oscillation frequency component.

[0008] Optionally, in one embodiment of this application, determining the design equivalent impedance or admittance control parameters based on the control input includes: selecting the corresponding admittance or impedance form based on the control input, and designing and optimizing the impedance or admittance control parameters based on the determined corresponding compensation current or compensation voltage.

[0009] Through the above-mentioned technical means, the embodiments of this application can select an appropriate impedance or admittance form based on the control input quantity, and then determine the corresponding compensation voltage or compensation current accordingly. The equivalent impedance / admittance control parameters are optimized and tuned based on the compensation electrical signal, so that the design of the control parameters is precisely matched with the control input quantity and the impedance / admittance control form, which fits the actual control requirements of the system and improves the design adaptability and rationality of the equivalent impedance / admittance control parameters.

[0010] Optionally, in one embodiment of this application, generating the first correction function includes: calculating the amplitude gain and phase delay at the oscillation frequency component; and determining the first correction function based on the amplitude gain and phase delay.

[0011] Through the above-mentioned technical means, the embodiments of this application can determine the first correction function by calculating the amplitude gain and phase delay at the oscillation frequency component. The correction function is accurately generated based on the quantitative index of the filter amplitude and phase characteristics, so that the parameter design fits the actual response characteristics of the filter at the oscillation frequency, improving the design accuracy and pertinence of the first correction function. This can lay an accurate parameter foundation for the subsequent correction optimization of impedance / admittance control and ensure effective suppression of the target oscillation frequency component.

[0012] Optionally, in one embodiment of this application, generating the second correction function includes: injecting a pre-set harmonic test current signal of amplitude and duration into the power electronic converter to obtain voltage and current waveforms, and plotting the amplitude-frequency and phase-frequency characteristic curves of the converter based on the voltage and current waveforms; determining the value of the transfer function at each frequency based on the amplitude-frequency and phase-frequency characteristic curves; fitting the transfer function of the converter based on the value; calculating the amplitude gain and phase delay at the target oscillation frequency based on the transfer function of the converter; and determining the second correction function based on the amplitude gain and phase delay.

[0013] Through the above-mentioned technical means, the embodiments of this application can obtain voltage and current waveforms by injecting a preset harmonic test current signal into the power electronic converter, plotting amplitude-frequency and phase-frequency characteristic curves, determining the transfer function values ​​at each frequency and fitting the converter transfer function, calculating the amplitude gain and phase delay at the target oscillation frequency to determine the second correction function, and quantitatively obtaining the correction function based on the actual transfer characteristics of the converter measured and fitted, so that the second correction function accurately matches the actual response characteristics of the converter to the target oscillation frequency, improving the accuracy and fit of parameter design, and providing reliable converter-side parameter support for the accurate correction of subsequent impedance / admittance control and the effective suppression of the target oscillation frequency component.

[0014] Optionally, in one embodiment of this application, determining the design equivalent impedance or admittance control parameters includes: optimizing the impedance or admittance parameters to find conductance and susceptance components that satisfy preset conditions, wherein the objective function for optimization is:

[0015] in, α 1~ α n Indicates correspondence n 1-th order matrix M The real part of the eigenvalues, ω 1~ ω n Indicates correspondence n 1-th order matrix M The result of dividing the imaginary part of the eigenvalue by the imaginary unit j, Y min and Y max These represent the upper and lower limits of the equivalent admittance amplitude, respectively, and the subscript os indicates the number corresponding to the oscillation mode to be suppressed.

[0016] Through the above-mentioned technical means, the embodiments of this application can transform the optimization of equivalent impedance / admittance control parameters into finding conductance and susceptance components that meet preset conditions. Alternatively, it can be transformed into the optimization of the amplitude and phase angle of admittance in polar coordinates. By solving for these optimal components, the oscillation components after the control loop are allowed to decay at the fastest speed, making the optimization of impedance / admittance parameters more targeted and quantitative, accurately pointing to the core objective of rapid oscillation suppression, improving the effectiveness of parameter optimization and the efficiency of oscillation suppression, and ensuring that the system can quickly recover to a stable state.

[0017] A second aspect of this application provides a self-calibrating broadband oscillation suppression device, comprising: a determination module, configured to extract a frequency mode corresponding to a control input quantity of a broadband filter, and determine an oscillation frequency component to be suppressed based on the frequency mode; a correction module, configured to generate a first correction function based on the amplitude-phase characteristics of the transfer function of the broadband filter, and generate a second correction function based on the response characteristics of a power electronic converter to the oscillation frequency; and a suppression module, configured to determine a design equivalent impedance or admittance control parameter based on the control input quantity, and control and suppress the oscillation frequency component by combining the first correction function, the second correction function, and the equivalent impedance or admittance control parameter.

[0018] Through the above-mentioned technical means, the embodiments of this application can first extract the frequency mode corresponding to the control input of the broadband filter, and then determine the oscillation frequency component to be suppressed; then generate the first and second correction functions based on the amplitude and phase characteristics of the broadband filter transfer function and the response characteristics of the power electronic converter to the oscillation frequency; finally, determine the design equivalent impedance or admittance control parameters based on the control input, and combine the two types of correction functions with the impedance / admittance control parameters. The established self-correcting control structure can adapt to a wide frequency range and effectively suppress low-frequency oscillations, sub- / super-synchronous oscillations, near-power frequency oscillations, and medium / high frequency oscillations, and can achieve precise suppression control of the target oscillation frequency component.

[0019] Optionally, in one embodiment of this application, the determining module includes: a design optimization unit, used to select the corresponding admittance or impedance form based on the control input quantity, and to design and optimize the impedance or admittance control parameters based on the determined corresponding compensation current or compensation voltage.

[0020] Through the above-mentioned technical means, the embodiments of this application can select an appropriate impedance or admittance form based on the control input quantity, and then determine the corresponding compensation voltage or compensation current accordingly. The equivalent impedance / admittance control parameters are optimized and tuned based on the compensation electrical signal, so that the design of the control parameters is precisely matched with the control input quantity and the impedance / admittance control form, which fits the actual control requirements of the system and improves the design adaptability and rationality of the equivalent impedance / admittance control parameters.

[0021] Optionally, in one embodiment of this application, the correction module includes: a first calculation unit, configured to calculate the amplitude gain and phase delay at the oscillation frequency component; and a first determination unit, configured to determine the first correction function based on the amplitude gain and phase delay.

[0022] Through the above-mentioned technical means, the embodiments of this application can determine the first correction function by calculating the amplitude gain and phase delay at the oscillation frequency component. The correction function is accurately generated based on the quantitative index of the filter amplitude and phase characteristics, so that the parameter design fits the actual response characteristics of the filter at the oscillation frequency, improving the design accuracy and pertinence of the first correction function. This can lay an accurate parameter foundation for the subsequent correction optimization of impedance / admittance control and ensure effective suppression of the target oscillation frequency component.

[0023] Optionally, in one embodiment of this application, the correction module further includes: a plotting unit, configured to inject a pre-set harmonic test current signal of amplitude and duration into the power electronic converter to obtain voltage and current waveforms, and plot the amplitude-frequency and phase-frequency characteristic curves of the converter based on the voltage and current waveforms; a second determining unit, configured to determine the value of the transfer function at each frequency based on the amplitude-frequency and phase-frequency characteristic curves; a fitting unit, configured to fit the transfer function of the converter based on the value; a second calculation unit, configured to calculate the amplitude gain and phase delay at the target oscillation frequency based on the transfer function of the converter; and a third determining unit, configured to determine the second correction function based on the amplitude gain and phase delay.

[0024] Through the above-mentioned technical means, the embodiments of this application can obtain voltage and current waveforms by injecting a preset harmonic test current signal into the power electronic converter, plotting amplitude-frequency and phase-frequency characteristic curves, determining the transfer function values ​​at each frequency and fitting the converter transfer function, calculating the amplitude gain and phase delay at the target oscillation frequency to determine the second correction function, and quantitatively obtaining the correction function based on the actual transfer characteristics of the converter measured and fitted, so that the second correction function accurately matches the actual response characteristics of the converter to the target oscillation frequency, improving the accuracy and fit of parameter design, and providing reliable converter-side parameter support for the accurate correction of subsequent impedance / admittance control and the effective suppression of the target oscillation frequency component.

[0025] Optionally, in one embodiment of this application, the optimization design unit is used to: optimize the impedance or admittance parameters equivalently to finding conductance and susceptance components that satisfy preset conditions, wherein the objective function for optimization is:

[0026] in, α 1~ α nIndicates correspondence n 1-th order matrix M The real part of the eigenvalues, ω 1~ ω n Indicates correspondence n 1-th order matrix M The result of dividing the imaginary part of the eigenvalue by the imaginary unit j, Y min and Y max These represent the upper and lower limits of the equivalent admittance amplitude, respectively, and the subscript os indicates the number corresponding to the oscillation mode to be suppressed.

[0027] Through the above-mentioned technical means, the embodiments of this application can transform the optimization of equivalent impedance / admittance control parameters into finding conductance and susceptance components that meet preset conditions. Alternatively, it can be transformed into the optimization of the amplitude and phase angle of admittance in polar coordinates. By solving for these optimal components, the oscillation components after the control loop are allowed to decay at the fastest speed, making the optimization of impedance / admittance parameters more targeted and quantitative, accurately pointing to the core objective of rapid oscillation suppression, improving the effectiveness of parameter optimization and the efficiency of oscillation suppression, and ensuring that the system can quickly recover to a stable state.

[0028] A third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the self-calibrating broadband oscillation frequency suppression method as described in the above embodiments.

[0029] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for suppressing self-calibrating broadband oscillation frequencies.

[0030] A fifth aspect of this application provides a computer program product that stores a computer program that, when executed by a processor, implements the above-described method for suppressing self-calibrating broadband oscillation frequencies.

[0031] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0032] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart of a self-calibrating broadband oscillation frequency suppression method provided according to an embodiment of this application; Figure 2This is a block diagram of the control loop of a self-calibrating broadband oscillation suppression method according to a specific embodiment of this application; Figure 3 This is a flowchart illustrating the implementation of a self-calibrating broadband oscillation suppression method according to a specific embodiment of this application; Figure 4 This is a schematic diagram of the structure of a self-calibrating broadband oscillation frequency suppression device according to an embodiment of this application; Figure 5 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application. Detailed Implementation

[0033] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0034] The following description, with reference to the accompanying drawings, illustrates a self-calibrating broadband oscillation frequency suppression method and apparatus according to embodiments of this application. Addressing the limitations of existing suppression methods mentioned in the background section, which fail to fully adapt to broadband oscillation characteristics and thus struggle to maintain stable suppression across the entire frequency band, varying frequencies, and multiple operating conditions, this application provides a self-calibrating broadband oscillation frequency suppression method. In this method, the oscillation frequency component to be suppressed is determined by extracting the frequency mode corresponding to the broadband filter control input. Then, based on the amplitude-phase characteristics of the broadband filter transfer function and the response characteristics of the power electronic converter to the oscillation frequency, first and second correction functions are generated respectively. Finally, by combining the equivalent impedance or admittance control parameters with the two types of correction functions, precise suppression control of the target oscillation frequency component is achieved. This solves the problems of existing suppression methods failing to fully adapt to broadband oscillation characteristics, thus hindering their ability to maintain stable suppression across the entire frequency band, varying frequencies, and multiple operating conditions, and limiting their applicability.

[0035] Specifically, Figure 1 This is a flowchart illustrating a method for suppressing self-calibrating broadband oscillation frequencies provided in an embodiment of this application.

[0036] like Figure 1 As shown, the method for suppressing the self-calibrating broadband oscillation frequency includes the following steps: In step S101, the frequency modes corresponding to the control input of the wideband filter are extracted, and the oscillation frequency components to be suppressed are determined based on the frequency modes.

[0037] The control input quantities are usually the voltage and current at the grid connection point / common coupling point, and are not specifically limited here.

[0038] In actual implementation, the embodiments of this application can extract the frequency modes to be controlled from the control input; a typical filter implementation consists of a triple structure of power frequency bandstop, coupled frequency bandstop, and target frequency bandpass; the prototype transfer function can be selected based on a comprehensive performance comparison, such as a common second-order filter, a Butterworth filter, or a Chebyshev filter.

[0039] To ensure versatility, the transfer function expression of a broadband filter... H k It can be set as follows:

[0040] In the formula, the subscript BS represents a band-stop filter, and BP represents a band-pass filter; the subscript... k Indicates the number of instances existing in the system. k There are oscillation patterns (total) N (each, starting with 0 to represent the power frequency).

[0041] In step S102, a first correction function is generated based on the amplitude and phase characteristics of the transfer function of the broadband filter, and a second correction function is generated based on the response characteristics of the power electronic converter to the oscillation frequency.

[0042] Optionally, in one embodiment of this application, generating a first correction function includes: calculating the amplitude gain and phase delay at the oscillation frequency component; and determining the first correction function based on the amplitude gain and phase delay.

[0043] Because the filter will cause a partial phase delay (and possibly amplitude) shift to the target oscillation frequency component, in order to accurately represent the actual dynamics of the oscillating phasor in the system, the correction element I is designed with the goal of completely canceling out the effect of the filter.

[0044] Specifically, for amplitude and phase correction stage I, the transfer function of the broadband filter is determined after the filter function, filter prototype and order are determined, so its amplitude and phase frequency characteristics can be obtained through offline calculation.

[0045] The transfer function expression of the broadband filter listed above H k For example, at the target oscillation frequency At that point, its equivalent magnitude gain (denoted as...) Phase delay (denoted as) They are respectively:

[0046]

[0047] Then, at this point, correction step I should also be applied to the frequency components. ω k With amplitude gain 1 / A f Phase delay - φ f .

[0048] Through the above-mentioned technical means, the embodiments of this application can determine the first correction function by calculating the amplitude gain and phase delay at the oscillation frequency component. The correction function is accurately generated based on the quantitative index of the filter amplitude and phase characteristics, so that the parameter design fits the actual response characteristics of the filter at the oscillation frequency, improving the design accuracy and pertinence of the first correction function. This can lay an accurate parameter foundation for the subsequent correction optimization of impedance / admittance control and ensure effective suppression of the target oscillation frequency component.

[0049] Optionally, in one embodiment of this application, generating the second correction function includes: injecting a pre-set harmonic test current signal of amplitude and duration into the power electronic converter to obtain voltage and current waveforms, and plotting the amplitude-frequency and phase-frequency characteristic curves of the converter based on the voltage and current waveforms; determining the value of the transfer function at each frequency based on the amplitude-frequency and phase-frequency characteristic curves; fitting the transfer function of the converter based on the value; calculating the amplitude gain and phase delay at the target oscillation frequency based on the transfer function of the converter; and determining the second correction function based on the amplitude gain and phase delay.

[0050] Since the existing internal control of the power electronic converter also affects the controlled signal, thus impacting the accuracy of impedance / admittance control, a correction stage II is designed to counteract the effect of the power electronic converter. Because its performance is similar to that of correction stage I, in practice, the two can be integrated into a single stage as needed.

[0051] Specifically, for amplitude and phase correction stage II, since the control logic adopted by the power electronic converter is usually a "black box" and difficult or impossible to know, its design needs to be carried out with the help of additional tests.

[0052] The specific process is as follows: (1) Obtain the relationship between input and output current by injecting a harmonic test current with appropriate amplitude and duration. Based on input information such as frequency, amplitude, and time, the output includes a test current signal with three stages: divergence, constant amplitude, and convergence. The voltage and current waveforms generated by the power electronic converter response are recorded, and the amplitude-frequency and phase-frequency characteristic curves of the converter are plotted.

[0053] (2) Transfer function regression fitting Based on the amplitude-frequency and phase-frequency characteristic curves obtained experimentally at various frequencies in (1), the value of the transfer function at each frequency can be derived. Still using the target oscillation frequency... ω k For example, it was learned through experiments that... s k = j ω k Time corresponding value G (j ω k Based on the obtained G (j ω k The value is used to fit the transfer function of an existing power electronic controller. G(s) .

[0054] G(s) The general form is expressed as Equation Section (Next):

[0055] In the formula, A ( s )≠0, n ≥ m , a 1~ a n , b 0~ b m Unknown. Also assume the orders of the numerator and denominator in the system transfer function are... m , n Given. Then:

[0056] Organize and write in matrix form:

[0057] Recorded as:

[0058] in:

[0059]

[0060] at this time, θ matrix( n + m The dimension can be obtained through a multiple linear regression algorithm.

[0061] Furthermore, the target frequency can be obtained based on the regression results. Amplitude gain at point and phase delay The control structure and parameters of this stage II are designed in accordance with the same principle as those of the calibration stage I.

[0062] Through the above-mentioned technical means, the embodiments of this application can obtain voltage and current waveforms by injecting a preset harmonic test current signal into the power electronic converter, plotting amplitude-frequency and phase-frequency characteristic curves, determining the transfer function values ​​at each frequency and fitting the converter transfer function, calculating the amplitude gain and phase delay at the target oscillation frequency to determine the second correction function, and quantitatively obtaining the correction function based on the actual transfer characteristics of the converter measured and fitted, so that the second correction function accurately matches the actual response characteristics of the converter to the target oscillation frequency, improving the accuracy and fit of parameter design, and providing reliable converter-side parameter support for the accurate correction of subsequent impedance / admittance control and the effective suppression of the target oscillation frequency component.

[0063] In step S103, the design equivalent impedance or admittance control parameters are determined based on the control input quantity, and the oscillation frequency components are controlled and suppressed by combining the first correction function, the second correction function, and the equivalent impedance or admittance control parameters.

[0064] Optionally, in one embodiment of this application, determining the design equivalent impedance or admittance control parameters based on the control input includes: selecting the corresponding admittance or impedance form based on the control input, and designing and optimizing the impedance or admittance control parameters based on the determined corresponding compensation current or compensation voltage.

[0065] This variable impedance / admittance element enables the controlled converter to exhibit the required impedance / admittance characteristics at the oscillation frequency, thereby changing the overall system's oscillation stability.

[0066] Specifically, when the control input is selected as the grid connection point voltage, this step should adopt the admittance form (…). Y=G+ j B The final output compensation current; when the input is selected as the grid connection point current, this step should adopt an impedance form ( Z=R+ j X ), which ultimately corresponds to the output compensation voltage.

[0067] Specific G, B, R, X The values ​​can be modeled in a reduced order based on the actual characteristics of the power system in the area where the self-calibrating control is applied, and the magnitude and phase angle of the design impedance / admittance can be obtained in an optimized manner.

[0068] Since the self-calibrating control function mentioned above is deployed in the power electronic converter, and the influence of the filter and the converter's internal control on the impedance / admittance calculation has been eliminated through the two-stage amplitude and phase correction links before and after, the goal of this optimization design is to change the impedance characteristics of the target system so that it can have a stable and decaying time-domain response under the original oscillation mode excitation.

[0069] Through the above-mentioned technical means, the embodiments of this application can select an appropriate impedance or admittance form based on the control input quantity, and then determine the corresponding compensation voltage or compensation current accordingly. The equivalent impedance / admittance control parameters are optimized and tuned based on the compensation electrical signal, so that the design of the control parameters is precisely matched with the control input quantity and the impedance / admittance control form, which fits the actual control requirements of the system and improves the design adaptability and rationality of the equivalent impedance / admittance control parameters.

[0070] Optionally, in one embodiment of this application, determining the design equivalent impedance or admittance control parameters includes: optimizing the impedance or admittance parameters to find conductance and susceptance components that satisfy preset conditions, wherein the objective function for optimization is:

[0071] Taking admittance as an example, let's record... Y = G +j B After the self-tuning control closed loop is activated, the equivalent circuit state matrix of the system at the target frequency is: M It is easy to know. M yes G, B The function, denoted as M ( G , B (Note separately) λ ( M ( G , B Characterization M Eigenvalues ​​of a matrix. M The order of the matrix depends on the form of the model used in the actual analysis and calculation. If we only consider the convergence and divergence, frequency, amplitude, and other response characteristics of a specific oscillation mode from the perspective of circuit analysis, then under ideal conditions... M It can be characterized by taking only the third order (the original second-order system with an additional controller).

[0072] At this point, optimizing the impedance / admittance parameters can be equivalent to finding the optimal conductance and susceptance components (in the case of complex numbers expressed in polar coordinates, these are the amplitude and phase angle). Y |、∠ Y This allows the oscillation component to decay at the fastest speed after the control loop is closed, as shown in the above formula.

[0073] In the formula, α 1~ α ncorrespond n 1-th order matrix M The real part of the eigenvalues, ω 1~ ω n correspond n 1-th order matrix M The result of dividing the imaginary part of the eigenvalue by the imaginary unit j, Y min and Y max These are the upper and lower limits of the equivalent admittance amplitude, respectively, and the subscript os represents the number corresponding to the oscillation mode to be suppressed.

[0074] The three constraints respectively limit the stability of the system across the entire frequency band, the degree of influence of the converter itself on the steady-state and transient response of the system, and the stability of the converter itself (equivalent to a resistor, it will not emit oscillating power).

[0075] Through the above-mentioned technical means, the embodiments of this application can transform the optimization of equivalent impedance / admittance control parameters into finding conductance and susceptance components that meet preset conditions. Alternatively, it can be transformed into the optimization of the amplitude and phase angle of admittance in polar coordinates. By solving for these optimal components, the oscillation components after the control loop are allowed to decay at the fastest speed, making the optimization of impedance / admittance parameters more targeted and quantitative, accurately pointing to the core objective of rapid oscillation suppression, improving the effectiveness of parameter optimization and the efficiency of oscillation suppression, and ensuring that the system can quickly recover to a stable state.

[0076] Furthermore, such as Figure 2 As shown, after completing the aforementioned amplitude and phase correction and variable impedance / admittance control, the voltage / current reference signal generated by the control can be injected into the actual physical system through power electronic conversion. Due to the diversity of converter types and functions, this part usually does not have uniform design requirements, but it is necessary to open several interfaces to achieve integration with the self-calibration control function.

[0077] Furthermore, such as Figure 3 As shown, to enable those skilled in the art to more clearly understand the above-described method for suppressing self-calibrating broadband oscillation frequencies, a specific embodiment is provided below for detailed explanation: Step S301: Obtain the oscillation frequency based on the monitoring and identification results; This step can obtain the broadband phasor information (mainly the oscillation frequency) corresponding to the oscillation through the existing broadband monitoring equipment in the system.

[0078] Step S302: Design the composition and transfer function of the broadband filter; This step involves selecting the composition, function, and prototype transfer function of a broadband filter based on the oscillation frequency to be suppressed. A typical filter structure is a power frequency bandstop-coupled frequency bandstop-target frequency bandpass filter. The prototype transfer function can be selected based on a comprehensive performance comparison, such as a Butterworth filter or a Chebyshev filter. Finally, the two are combined to calculate the corresponding transfer function.

[0079] Step S303: Design correction stage I based on the amplitude and phase characteristics of the filter transfer function; Since the filter designed in step S302 will cause a partial phase delay (and possibly amplitude) shift to the target oscillation frequency component, in order to accurately represent the actual dynamics of the oscillating phasor in the system, a correction element I is designed with the goal of completely canceling out the effect of the filter.

[0080] Step S304: Design correction circuit II based on the response characteristics of the power electronic converter to the target frequency; Similar to step S303, since the existing internal control of the power electronic converter also affects the controlled signal, thereby affecting the accuracy of impedance / admittance control, correction stage II is designed with the goal of counteracting the effect of the power electronic converter.

[0081] Step S305: Optimize the design of the equivalent impedance / admittance element based on the characteristic parameters of the power system in this region; This step can perform reduced-order modeling based on the actual characteristics of the power system in the area where self-calibrating control is implemented, and optimize the magnitude and phase angle of the design impedance / admittance.

[0082] Step S306: Configure, test, and run the self-calibration control function; This step integrates the above implementation steps and uses appropriate software and hardware implementation methods to deploy the self-calibration control function in the control module of an appropriate power electronic converter (such as energy storage, SVG, STATCOM, etc.). After testing, it can be put into operation.

[0083] This embodiment, based on the above technical solution, has the following advantages: 1. The established self-calibrating control structure can adapt to a wide frequency range and effectively suppress low-frequency oscillations, sub / supersynchronous oscillations, near-power frequency oscillations, and medium / high frequency oscillations.

[0084] 2. The amplitude and phase correction stage can reduce the amplitude and phase deviation caused by signal processing and inherent power electronic control, thereby improving the damping control effect.

[0085] The self-calibrating broadband oscillation frequency suppression method proposed in this application can determine the oscillation frequency component to be suppressed by extracting the frequency mode corresponding to the control input of the broadband filter. Then, based on the amplitude and phase characteristics of the broadband filter transfer function and the response characteristics of the power electronic converter to the oscillation frequency, first and second correction functions are generated respectively. Finally, by combining the equivalent impedance or admittance control parameters with the two types of correction functions, precise suppression control of the target oscillation frequency component can be achieved. This solves the problems of existing suppression methods, which fail to achieve comprehensive adaptation to broadband oscillation characteristics, making it difficult to maintain a stable suppression effect across the entire frequency band, variable frequency, and multiple operating conditions, and limiting their applicability.

[0086] Next, refer to the appendix. Figure 4 This application describes a self-calibrating broadband oscillation frequency suppression device according to embodiments thereof.

[0087] Figure 4 This is a block diagram of a self-calibrating broadband oscillation frequency suppression device according to an embodiment of this application.

[0088] like Figure 4 As shown, the self-calibrating broadband oscillation frequency suppression device 10 includes: a determination module 100, a calibration module 200, and a suppression module 300.

[0089] The determining module 100 is used to extract the frequency modes corresponding to the control input of the wideband filter, and to determine the oscillation frequency components to be suppressed based on the frequency modes.

[0090] The correction module 200 is used to generate a first correction function based on the amplitude and phase characteristics of the transfer function of the broadband filter, and to generate a second correction function based on the response characteristics of the power electronic converter to the oscillation frequency.

[0091] The suppression module 300 is used to determine the design equivalent impedance or admittance control parameters based on the control input quantity, and to control and suppress the oscillation frequency components by combining the first correction function, the second correction function, and the equivalent impedance or admittance control parameters.

[0092] Optionally, in one embodiment of this application, the determining module 100 includes: a design optimization unit, which is used to select the corresponding admittance or impedance form based on the control input quantity, and to design and optimize the impedance or admittance control parameters based on the determined corresponding compensation current or compensation voltage.

[0093] Optionally, in one embodiment of this application, the correction module 200 includes: a first calculation unit and a first determination unit; wherein, the first calculation unit is used to calculate the amplitude gain and phase delay at the oscillation frequency component; and the first determination unit is used to determine a first correction function based on the amplitude gain and phase delay.

[0094] Optionally, in one embodiment of this application, the correction module 200 further includes: a plotting unit, second and third determining units, a fitting unit, and a second calculation unit; wherein, the plotting unit is used to inject a pre-set harmonic test current signal of amplitude and duration into the power electronic converter to obtain voltage and current waveforms, and plot the amplitude-frequency and phase-frequency characteristic curves of the converter based on the voltage and current waveforms; the second determining unit is used to determine the value of the transfer function at each frequency based on the amplitude-frequency and phase-frequency characteristic curves; the fitting unit is used to fit the transfer function of the converter based on the value; the second calculation unit is used to calculate the amplitude gain and phase delay at the target oscillation frequency based on the transfer function of the converter; and the third determining unit is used to determine the second correction function based on the amplitude gain and phase delay.

[0095] Optionally, in one embodiment of this application, the optimization design unit is used to: optimize the parameters of impedance or admittance by finding conductance and susceptance components that satisfy preset conditions, wherein the objective function of optimization is:

[0096] in, α 1~ α n Indicates correspondence n 1-th order matrix M The real part of the eigenvalues, ω 1~ ω n Indicates correspondence n 1-th order matrix M The result of dividing the imaginary part of the eigenvalue by the imaginary unit j, Y min and Y max These represent the upper and lower limits of the equivalent admittance amplitude, respectively, and the subscript os indicates the number corresponding to the oscillation mode to be suppressed.

[0097] It should be noted that the explanation of the aforementioned embodiment of the method for suppressing self-calibrated broadband oscillation frequency also applies to the device for suppressing self-calibrated broadband oscillation frequency in this embodiment, and will not be repeated here.

[0098] The self-calibrating broadband oscillation frequency suppression device proposed in this application can determine the oscillation frequency component to be suppressed by extracting the frequency mode corresponding to the control input of the broadband filter. Then, based on the amplitude and phase characteristics of the broadband filter transfer function and the response characteristics of the power electronic converter to the oscillation frequency, first and second correction functions are generated respectively. Finally, by combining the equivalent impedance or admittance control parameters with the two types of correction functions, precise suppression control of the target oscillation frequency component can be achieved. This solves the problems of existing suppression methods, which fail to achieve comprehensive adaptation to broadband oscillation characteristics, making it difficult to maintain a stable suppression effect across the entire frequency band, variable frequency, and multiple operating conditions, and limiting their applicability.

[0099] Figure 5 A schematic diagram of the structure of an electronic device provided in an embodiment of this application. The electronic device may include: The memory 501, the processor 502, and the computer program stored on the memory 501 and capable of running on the processor 502.

[0100] When the processor 502 executes the program, it implements the self-calibrating wideband oscillation frequency suppression method provided in the above embodiments.

[0101] Furthermore, electronic devices also include: Communication interface 503 is used for communication between memory 501 and processor 502.

[0102] The memory 501 is used to store computer programs that can run on the processor 502.

[0103] Memory 501 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0104] If the memory 501, processor 502, and communication interface 503 are implemented independently, then the communication interface 503, memory 501, and processor 502 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 5 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0105] Optionally, in a specific implementation, if the memory 501, processor 502, and communication interface 503 are integrated on a single chip, then the memory 501, processor 502, and communication interface 503 can communicate with each other through an internal interface.

[0106] Processor 502 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0107] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the above-described method for suppressing self-correcting broadband oscillations.

[0108] This application also provides a computer program product storing a computer program that, when executed by a processor, implements the above-described method for suppressing self-correcting broadband oscillations.

[0109] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0110] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0111] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0112] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0113] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, it can be implemented using any one or more of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0114] Those skilled in the art will understand that all or part of the steps of the methods described in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it includes one or a combination of the steps of the method embodiments.

[0115] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0116] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A method for suppressing self-calibrating broadband oscillations, characterized in that, Includes the following steps: Extract the frequency modes corresponding to the control input of the broadband filter, and determine the oscillation frequency components to be suppressed based on the frequency modes; A first correction function is generated based on the amplitude and phase characteristics of the transfer function of the broadband filter, and a second correction function is generated based on the response characteristics of the power electronic converter to the oscillation frequency. The equivalent impedance or admittance control parameters are determined based on the control input, and the oscillation frequency components are suppressed by combining the first correction function, the second correction function, and the equivalent impedance or admittance control parameters.

2. The method according to claim 1, characterized in that, The step of determining the design equivalent impedance or admittance control parameters based on the control input includes: Based on the control input, the corresponding admittance or impedance form is selected, and the corresponding compensation current or compensation voltage is determined to design and optimize the impedance or admittance control parameters based on the compensation current or compensation voltage.

3. The method according to claim 1, characterized in that, The generation of the first correction function includes: Calculate the amplitude gain and phase delay at the oscillation frequency component; The first correction function is determined based on the amplitude gain and phase delay.

4. The method according to claim 1, characterized in that, The generation of the second correction function includes: A pre-set harmonic test current signal with a predetermined amplitude and duration is injected into the power electronic converter to obtain voltage and current waveforms, and the amplitude-frequency and phase-frequency characteristic curves of the converter are plotted based on the voltage and current waveforms. The value of the transfer function at each frequency is determined based on the amplitude-frequency and phase-frequency characteristic curves. The transfer function of the converter is fitted based on the values; Calculate the amplitude gain and phase delay at the oscillation frequency based on the transfer function of the converter; The second correction function is determined based on the amplitude gain and phase delay.

5. The method according to claim 1, characterized in that, The determination of the design equivalent impedance or admittance control parameters includes: Optimizing the impedance or admittance parameters is equivalent to finding the conductance and susceptance components that satisfy preset conditions, where the objective function for optimization is: in, α 1~ α n Indicates correspondence n 1-th order matrix M The real part of the eigenvalues, ω 1~ ω n Indicates correspondence n 1-th order matrix M The result of dividing the imaginary part of the eigenvalue by the imaginary unit j, Y min and Y max These represent the upper and lower limits of the equivalent admittance amplitude, respectively, and the subscript os indicates the number corresponding to the oscillation mode to be suppressed.

6. A self-calibrating broadband oscillation suppression device, characterized in that, include: The determination module is used to extract the frequency modes corresponding to the control input of the wideband filter, and determine the oscillation frequency components to be suppressed based on the frequency modes; The correction module is used to generate a first correction function based on the amplitude and phase characteristics of the transfer function of the broadband filter, and to generate a second correction function based on the response characteristics of the power electronic converter to the oscillation frequency. The suppression module is used to determine the design equivalent impedance or admittance control parameters based on the control input, and to control and suppress the oscillation frequency components in combination with the first correction function, the second correction function, and the equivalent impedance or admittance control parameters.

7. The apparatus according to claim 6, characterized in that, The determining module includes: The design optimization unit is used to select the corresponding admittance or impedance form based on the control input quantity, and to design and optimize the impedance or admittance control parameters based on the determined compensation current or compensation voltage.

8. An electronic device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the self-calibrating broadband oscillation suppression method as described in any one of claims 1-5.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the method for suppressing self-calibrating broadband oscillations as described in any one of claims 1-5.

10. A computer program product, characterized in that, The computer program is executed to implement the method for suppressing self-correcting broadband oscillations as described in any one of claims 1-5.

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