Network configuration type converter parameter identification method based on static frequency response

Abstract

This invention discloses a parameter identification method for a grid-type converter based on static frequency response. The method includes: applying a controllable small disturbance signal to the control input interface under the static steady-state operation of the grid-type converter; acquiring port voltage and current response data under corresponding experimental scenarios by combining boundary conditions; performing fast Fourier transform processing on the acquired port voltage and current response data to extract the complex spectrum values ​​of the disturbance signal and response data, and calculating the amplitude-frequency and phase-frequency characteristics of the target transfer function based on the spectrum ratio; decoupling the control parameters stepwise according to the amplitude-frequency characteristic inflection point and low-frequency gain under each experimental scenario to eliminate the influence of multi-parameter coupling, and identifying the equivalent parameters of the power loop, voltage loop, and reactive power loop respectively; mapping the identified control parameters to the physical characteristics of the synchronous machine equivalent model, and establishing a dynamic model including rotor motion equation parameters, voltage controller parameters, and reactive power controller parameters.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and in particular to a method for identifying parameters of a grid-type converter based on static frequency response. Background Technology

[0002] Grid-connected converters (GFMs), as core equipment in power electronic system modeling and parameter identification technology, are widely used in the field of new energy grid connection. Among related technologies, a technical system for GFM parameter identification has been constructed through the collaborative operation of impedance modeling, dynamic data-driven modeling, and gray-box modeling based on control structures. Specifically, this system covers the entire process from steady-state impedance characteristic analysis to nonlinear dynamic modeling, including the nonlinear mapping construction of the frequency domain impedance matrix based on Fourier transform, and parameter estimation of known control structures using the least squares method. The black-box method relies on input and output data for equivalent model reconstruction, while the gray-box method combines prior knowledge of the control topology to achieve parameter identification. However, existing GFM parameter identification methods, such as impedance modeling which directly uses linearization assumptions, do not consider the nonlinear dynamic characteristics under large disturbances, which may lead to biases in transient stability analysis. While dynamic data-driven modeling can capture nonlinear characteristics through algorithms such as neural networks and Gaussian process regression, its modeling results lack physical interpretability and require a large number of high-quality training samples, thus affecting the engineering applicability of the model. While the gray-box approach based on control structures has physical significance, its reliance on prior knowledge of internal control parameters limits its application in scenarios with unknown control structures. Specifically, the time-domain reconstruction algorithm is sensitive to noise, and switching control modes during experiments may introduce system instability risks. Furthermore, the parameters of the data-driven model are only statistically significant and cannot be directly mapped to specific control components. These technical limitations result in significant deficiencies in the safety, interpretability, and engineering adaptability of existing methods, restricting the dynamic modeling accuracy and control optimization capabilities of GFM devices in complex power grid environments. Summary of the Invention

[0003] The main objective of this invention is to provide a method for identifying parameters of a grid-type converter based on its static frequency response.

[0004] Another objective of this invention is to provide a parameter identification device for a grid-type converter based on static frequency response.

[0005] The third objective of this invention is to provide a computer device.

[0006] A fourth objective of this invention is to provide a non-transitory computer-readable storage medium.

[0007] To achieve the above objectives, a first aspect of the present invention proposes a method for parameter identification of a grid-type converter based on its stationary frequency response, comprising:

[0008] S1. Under the static steady-state operation of the grid-type converter, a controllable small disturbance signal is applied to the control input interface. By adjusting the combined boundary conditions of the active power reference command, reactive power reference command, and voltage reference value, the port voltage and current response data under the corresponding experimental scenarios are obtained respectively. Among them, the experimental scenarios include active power characteristic parameter measurement experiment, combined parameter measurement experiment 1, combined parameter measurement experiment 2, and reactive power characteristic parameter measurement experiment. S2, for each experimental scenario, the collected port voltage and current response data are processed by Fast Fourier Transform to extract the complex spectrum values ​​of the disturbance signal and the response data. Based on the preset target transfer function type for each experiment, the amplitude-frequency characteristics and phase-frequency characteristics of the corresponding transfer function are calculated by the ratio of the complex spectrum values, providing data support for subsequent parameter decoupling; the amplitude-frequency characteristics and phase-frequency characteristics of the target transfer function; S3, based on the amplitude-frequency characteristic inflection point and low-frequency gain step-by-step decoupling control parameters under each experimental scenario, eliminates the multi-parameter coupling effect through independent experimental conditions of open circuit or short circuit conditions; accurately identifies the equivalent parameters related to power loop, voltage loop, filter link, virtual impedance and reactive power control respectively. S4. Map the equivalent parameters obtained from the identified control parameters to the physical characteristics of the synchronous machine equivalent model, establish a dynamic model including rotor motion equation parameters, voltage controller parameters and reactive power controller parameters, and output the dynamic model and the corresponding identified parameters to realize power system transient stability analysis and control optimization.

[0009] In one embodiment of the present invention, the active power characteristic parameter measurement experiment specifically includes: The control grid-type converter port is in an open circuit state, the reactive power reference command is set to 0, and the active power reference command is set to a sinusoidal signal with a variable frequency superimposed near 0. The frequency value of the sinusoidal signal covers the inflection point frequency band of the target transfer function. A phase-locked loop is used to detect the angular frequency of the port voltage at the converter output port. Angular frequency response data is obtained under active power reference command values ​​at different frequencies. Fast Fourier Transform (FFT) processing is performed on the sinusoidal signal and angular frequency response data respectively, and the complex spectrum values ​​of the two at the applied signal frequency are extracted. The transfer function is calculated based on the ratio of the complex spectrum values. .

[0010] In one embodiment of the present invention, the combined parameter measurement experiment 1 specifically includes: With the control grid-type converter port in an open-circuit state, the active power reference command and reactive power reference command are set to 0, and the voltage reference value is... The method is to superimpose a sinusoidal signal with a variable frequency onto a constant value, wherein the frequency of the sinusoidal signal covers the inflection point frequency band of the target transfer function; The three-phase voltage at the converter output port is acquired. A Park transform is performed on the three-phase voltage using the integral angle at the reference frequency as a reference, yielding the voltage components in the dq coordinate system. Fast Fourier Transforms are then performed on the sinusoidal signal and the two voltage components in the dq coordinate system, respectively, to extract the complex spectrum values ​​of the three components at the applied signal frequency, denoted as follows: , and ,based on and The voltage-dq axis transfer function is obtained by calculating the ratio. ,based on and The ratio and combined The voltage-voltage transfer function is derived. .

[0011] In one embodiment of the present invention, the combined parameter measurement experiment 2 specifically includes: With the control grid-type converter port in a short-circuit state, the active power reference command and reactive power reference command are set to 0, and the voltage reference value is... The system is configured to superimpose a variable frequency sine wave onto a base of 0, wherein the frequency values ​​of the sine wave cover the inflection point frequency band of the target transfer function. The three-phase current at the converter output port is collected. Fast Fourier Transform (FFT) is performed on both the sinusoidal signal and the three-phase current to extract their complex spectral values ​​at the applied signal frequency. The voltage-current transfer function is calculated based on the ratio of these complex spectral values. .

[0012] In one embodiment of the present invention, the reactive power characteristic parameter measurement experiment specifically includes: The control grid-type converter port is in a short-circuit state, the active power reference command is set to 0, the voltage reference value is set to 0, and the reactive power reference command is set to a sinusoidal signal with variable frequency superimposed on 0. The frequency value of the sinusoidal signal covers the inflection point frequency band of the target transfer function. The three-phase current at the converter output port is collected. Fast Fourier Transform (FFT) is performed on both the sinusoidal signal and the three-phase current to extract their complex spectral values ​​at the applied signal frequency. The reactive-current transfer function is calculated based on the ratio of these complex spectral values. .

[0013] In one embodiment of the present invention, the step-by-step decoupling control parameters in step S3 are specifically as follows: Based on the transfer functions obtained in step S2, the corresponding amplitude-frequency characteristic curves and phase-frequency characteristic curves are plotted. By extracting the low-frequency amplitude and inflection point frequency of the amplitude-frequency characteristic curves, and combining the mathematical model relationships corresponding to each experiment with the decoupling effect of independent open-circuit and short-circuit conditions, the multi-parameter coupling effect is eliminated, and the correlation coefficient of the power loop, the control parameters of the voltage loop, the parameters of the filter loop, and the related parameters of the virtual impedance are calculated respectively.

[0014] To achieve the above objectives, a second aspect of the present invention provides a parameter identification device for a grid-type converter based on its stationary frequency response, comprising: The disturbance application and data acquisition module is used to apply a controllable small disturbance signal to the control input interface under the static steady-state operation of the grid-type converter. By adjusting the combined boundary conditions of the active power reference command, reactive power reference command, and voltage reference value, it acquires the port voltage and current response data under the corresponding experimental scenarios. The experimental scenarios include active power characteristic parameter measurement experiment, combined parameter measurement experiment 1, combined parameter measurement experiment 2, and reactive power characteristic parameter measurement experiment. The frequency domain characteristic analysis module is used to perform fast Fourier transform processing on the port voltage and current response data collected in various experimental scenarios, extract the complex spectrum values ​​of the disturbance signal and response data, and calculate the amplitude frequency characteristics and phase frequency characteristics of the corresponding transfer function by the ratio of the complex spectrum values ​​according to the target transfer function type preset for each experiment, so as to provide data support for subsequent parameter decoupling. The step-by-step decoupling parameter identification module is used to decouple control parameters step by step according to the amplitude-frequency characteristic inflection point and low-frequency gain corresponding to each experimental scenario. It eliminates the influence of multi-parameter coupling through independent experimental conditions of open circuit or short circuit conditions; and accurately identifies the equivalent parameters related to power loop, voltage loop, filtering link, virtual impedance and reactive power control. The equivalent model construction module is used to map the identified equivalent parameters to the physical characteristics of the synchronous machine equivalent model, establish a dynamic model including rotor motion equation parameters, voltage controller parameters and reactive power controller parameters, and output the dynamic model and the corresponding identified parameters to realize power system transient stability analysis and control optimization.

[0015] To achieve the above objectives, a third aspect of this application provides a computer device, including a processor and a memory; wherein the processor reads executable program code stored in the memory to run a program corresponding to the executable program code, for implementing a grid-type converter parameter identification method based on static frequency response as described in the first aspect embodiment.

[0016] To achieve the above objectives, a fourth aspect of this application provides a non-transitory computer-readable storage medium storing a computer program that, when executed by a processor, implements a method for identifying grid-type converter parameters based on static frequency response as described in the first aspect embodiment.

[0017] The embodiments of the present invention have the following beneficial effects: This invention obtains the system's frequency domain characteristics by applying a small-amplitude frequency sweep disturbance under static conditions, without switching control modes or entering transient processes, significantly reducing experimental risks. This invention requires no prior control information and can obtain key control parameters even without knowing the internal control structure, achieving true black-box parameter identification, and is applicable to various types of grid-connected converters. This invention uses a combination of step-by-step experiments and frequency response fitting to transform multi-parameter coupled problems into grouped solutions, improving the robustness and consistency of parameter identification. The only instruments required for this invention are voltage and current sampling devices and a programmable disturbance signal source, facilitating rapid implementation in laboratories and engineering sites. Although the experiment is conducted under static conditions, the obtained parameters can be directly used for transient response modeling and stability analysis, providing quantitative basis for subsequent control optimization. Attached Figure Description

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 A flowchart illustrating a method for parameter identification of a grid-type converter based on static frequency response, provided in an embodiment of the present invention; Figure 2 A control flowchart for a grid-type converter provided in an embodiment of the present invention; Figure 3 A diagram showing the change in port voltage vector before and after disturbance injection, provided in an embodiment of the present invention; Figure 4 This is a structural diagram of a grid-type converter parameter identification device based on static frequency response, provided in an embodiment of the present invention. Detailed Implementation

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] The following describes, with reference to the accompanying drawings, a method for parameter identification of a grid-type converter based on static frequency response according to an embodiment of the present invention.

[0022] Example 1 This embodiment provides a method for parameter identification of a grid-type converter based on its static frequency response. For example... Figure 1 As shown, the method includes the following steps: S1. Under the static steady-state operation of the grid-type converter, a controllable small disturbance signal is applied to the control input interface. By adjusting the combined boundary conditions of the active power reference command, reactive power reference command, and voltage reference value, the port voltage and current response data under the corresponding experimental scenarios are obtained respectively. Among them, the experimental scenarios include active power characteristic parameter measurement experiment, combined parameter measurement experiment 1, combined parameter measurement experiment 2, and reactive power characteristic parameter measurement experiment.

[0023] It should be noted that for grid-type converters currently in practical applications, their mathematical control model can be divided into a control section and a filter circuit section. The control section can be further divided into a synchronization loop, a voltage controller, and a current controller; the filter circuit section can be divided into inductor characteristics and capacitor characteristics. The overall process is as follows: the power synchronization loop generates a reference voltage command, the input voltage controller generates a reference current command and inputs it to the current controller, the current controller outputs a modulation signal, which is then modulated by PWM to drive the filter circuit.

[0024] Furthermore, to facilitate understanding of the entire control process, the equations corresponding to different parts are mapped to different circuits or systems. The mathematical form of the power synchronization loop corresponds to the rotor motion equation and excitation system of a synchronous generator. Based on the speed of the transient process of the control response, it is divided into: the voltage control loop combined with the parallel virtual impedance is equivalent to a transient circuit; the current loop, excluding the parallel virtual impedance and combining with the inductor characteristics, is equivalent to a subtransient circuit; and the capacitor is equivalent to a power output circuit, serving as an interface for connection to external circuits. If the port characteristics on the transient timescale are of interest, the dynamic process of the subtransient circuit need not be considered, as it can be assumed to have reached stability. Therefore, this parameter measurement experiment focuses only on the parameter measurements of the parts other than the current control loop and the inductor.

[0025] Similar to the rotor motion equations and excitation system equations of a synchronous machine, such as Figure 2 As shown, all power synchronization strategies in the power loop can be uniformly expressed by the following formula:

[0026] Specifically, the core of parameter measurement is changing the control input interface signal when the converter control is in a black box, that is, when the control structure and parameters are unknown. , , ), by observing the response of the electrical quantities at the port ( , This allows for the calculation of all parameters in the model, which are then used for model construction and stability analysis.

[0027] This embodiment obtains all parameters in the model through four core experiments, including an active power characteristic parameter measurement experiment, a combined parameter measurement experiment 1, a combined parameter measurement experiment 2, and a reactive power characteristic parameter measurement experiment. The experimental conditions and the parameters obtained for each experiment are shown in Table 1.

[0028] Table 1

[0029] Furthermore, it specifically includes the following four core experiments: (1) Active characteristic parameter measurement experiment, which specifically includes: The control grid-type converter port is in an open circuit state, the reactive power reference command is set to 0, and the active power reference command is set to a sinusoidal signal with a variable frequency superimposed near 0. The frequency value of the sinusoidal signal covers the inflection point frequency band of the target transfer function.

[0030] A phase-locked loop is used to detect the angular frequency of the port voltage at the converter output port. Angular frequency response data is obtained under active power reference command values ​​at different frequencies. Fast Fourier Transform (FFT) processing is performed on the sinusoidal signal and angular frequency response data respectively, and the complex spectrum values ​​of the two at the applied signal frequency are extracted. The transfer function is calculated based on the ratio of the complex spectrum values. .

[0031] Specifically, the purpose of this experiment is to measure the equation of motion of the simulated rotor. and In this experiment, the transfer function to be measured is:

[0032] Furthermore, to ensure the control variable is unique, the experimental scenario is set to no-load, meaning the converter does not transmit power. To measure the parameter values ​​in the transfer function, the amplitude-frequency characteristic is plotted using the frequency sweep method. Although there is a delay from the generation of the phase reference by the power synchronization loop to actual control, this delay is on the same order of magnitude as the switching period and will not affect the low-to-mid-frequency range of the amplitude-frequency characteristic. Meanwhile, the transient process of the voltage loop will also affect the amplitude-frequency characteristic curve near its frequency range (typically 100 rad / s). However, since the converter is designed to make the time scales of each control loop as independent as possible, the transient process of the power synchronization loop is approximately considered slower than that of the voltage loop. The experimental steps include: First, disconnect the converter port. The active reference command is a sinusoidal signal with a variable frequency superimposed near 0, i.e. ,in This represents the amplitude of the superimposed signal; It varies in experiments, and its value needs to cover the inflection point of the transfer function of interest.

[0033] Next, a phase-locked loop (PLL) (requiring a dynamic range much faster than the applied signal frequency) is used at the converter output port to detect the angular frequency of the port voltage. The angular frequency response is obtained for different power reference frequencies. A fast Fourier transform is then used to obtain the port voltage angular frequency response and the complex values ​​of the input reference power at the applied small signal frequency, denoted as follows: and Then the transfer function value at that frequency is Based on this, it can be drawn The amplitude and phase frequency characteristics can be determined by the amplitude frequency characteristics in the low-frequency range and the inflection point frequency. and .

[0034] (2) Experiment 1 for measuring combined parameters, which specifically includes: With the control grid-type converter port in an open-circuit state, the active power reference command and reactive power reference command are set to 0, and the voltage reference value is... The method is to superimpose a sinusoidal signal with a variable frequency onto a constant value, wherein the frequency of the sinusoidal signal covers the inflection point frequency band of the target transfer function.

[0035] The three-phase voltage at the converter output port is acquired. A Park transform is performed on the three-phase voltage using the integral angle at the reference frequency as a reference, yielding the voltage components in the dq coordinate system. Fast Fourier Transforms are then performed on the sinusoidal signal and the two voltage components in the dq coordinate system, respectively, to extract the complex spectrum values ​​of the three components at the applied signal frequency, denoted as follows: , and ,based on and The voltage-dq axis transfer function is obtained by calculating the ratio. ,based on and The ratio and combined The voltage-voltage transfer function is derived. .

[0036] Specifically, the purpose of this experiment is to obtain a series of combined parameter values ​​involved in the transfer function of the voltage reference-port voltage. The experimental scenario is: the converter port is open-circuited, i.e., the d-axis current and q-axis current are both 0, and the control... and At this time, the d-axis and q-axis voltages are completely controlled by... Decision made. The equation can then be obtained:

[0037] For grid-type converters, the synchronization angle is generated internally by the control system. Since the scenario in this experiment is a set-case... Therefore, the synchronization angle generated by the power synchronization loop is the integral of the reference frequency; from equation 1 in the equation, we can obtain that when When the voltage is constant and the system is stable, the q-axis voltage is 0, and the d-axis voltage equals the resultant voltage. If an angular frequency of is applied to it at this point... sinusoidal disturbance ( (It needs to cover the frequency band of interest), that is Then the direction of the voltage synthesis vector will shift; but at this time, due to and Both are still 0, therefore the synchronization angle is at This will not happen in a rotated coordinate system, such as Figure 3 As shown, a perturbation signal is applied at time 0. At this time, the perturbation signal is applied to... Perform Park transformation, angle usage You can get points by accumulating them. and Then FFT obtained the values ​​of both. The response at frequency is denoted as and Then we have:

[0038] Furthermore, it is possible to draw The amplitude-frequency response is used to determine the values ​​of the following combined parameters: , , At the same time, according to Equation 2 and The relationship in Equation 1 Replace with And by deformation, we obtain:

[0039] Also in At a frequency, if the complex form has already been obtained Measure and calculate at the same frequency Then the above equation can be transformed into:

[0040] Therefore, it can be based on the drawing The amplitude-frequency response and phase-frequency response of the [symbol / frequency response] are used to obtain the following combined parameter values ​​based on its amplitude-frequency response: , Thus far, the experiment has measured a total of four combined parameters: , , , .

[0041] (3) Experiment 2 on combined parameter measurement, which specifically includes: With the control grid-type converter port in a short-circuit state, the active power reference command and reactive power reference command are set to 0, and the voltage reference value is... It is set to superimpose a variable frequency sine signal on a base of 0, wherein the frequency value of the sine signal covers the inflection point frequency band of the target transfer function.

[0042] The three-phase current at the converter output port is collected. Fast Fourier Transform (FFT) is performed on both the sinusoidal signal and the three-phase current to extract their complex spectral values ​​at the applied signal frequency. The voltage-current transfer function is calculated based on the ratio of these complex spectral values. .

[0043] Specifically, even through voltage mapping experiments, the values ​​of each circuit component in the model could not be obtained. First, the experimental scenario was set up as a short circuit at the converter port, controlling... and The formula under this setting can be simplified to:

[0044] Furthermore, set The initial value is 0, and an angular frequency of is applied on top of it. sinusoidal disturbance ( (The frequency band of interest needs to be covered), measure the port current response, perform FFT analysis on it, and obtain its value in... The amplitude of the component at the angular frequency, divided by the amplitude of the disturbance, yields the amplitude-frequency characteristic of the transfer function as follows:

[0045] The values ​​of the following parameters can be obtained from this amplitude-frequency characteristic: , By combining the combined parameters in Experiment 1, the values ​​of all voltage and current loop control parameters can be obtained.

[0046] (4) Reactive power characteristic parameter measurement experiment, which specifically includes: The control grid-type converter port is in a short-circuit state. The active power reference command is set to 0 and the voltage reference value is set to 0. The reactive power reference command is set to a sinusoidal signal with a variable frequency superimposed on 0. The frequency of the sinusoidal signal covers the inflection point frequency band of the target transfer function.

[0047] The three-phase current at the converter output port is collected. Fast Fourier Transform (FFT) is performed on both the sinusoidal signal and the three-phase current to extract their complex spectral values ​​at the applied signal frequency. The reactive-current transfer function is calculated based on the ratio of these complex spectral values. .

[0048] In this embodiment, since the transfer function of the voltage reference to the port current has already been obtained in the voltage-current characteristic experiment, if the transfer function of the reactive power reference to the port current can be obtained, it can be compared with the transfer function of the voltage reference to the port current to obtain the desired result. and The value of .

[0049] This experiment is set up to control a short circuit at the converter port, controlling... and .set up The initial value is 0, and an angular frequency of is applied on top of it. sinusoidal disturbance ( (The frequency band of interest needs to be covered), measure the port current response, perform FFT analysis on it, and obtain its value in... The amplitude of the component at angular frequency, and its relationship with Dividing the amplitudes of the disturbances by the amplitudes yields the following amplitude-frequency characteristic of the transfer function:

[0050] Furthermore, the obtained and By subtracting the amplitude-frequency response curves, we can obtain... Its amplitude-frequency characteristics can be obtained from its amplitude-frequency characteristics. and The specific values ​​are now obtained. This gives us all the parameters in the control system except for the current loop.

[0051] S2. Fast Fourier Transform is performed on the port voltage and current response data collected in each experimental scenario to extract the complex spectrum values ​​of the disturbance signal and response data. Based on the target transfer function type preset for each experiment, the amplitude-frequency characteristics and phase-frequency characteristics of the corresponding transfer function are calculated by the ratio of the complex spectrum values, providing data support for subsequent parameter decoupling.

[0052] In this embodiment, for the active power characteristic parameter measurement experiment, the sinusoidal signal and angular frequency response data are processed by Fast Fourier Transform, and the complex values ​​of both at the applied signal frequency are extracted, denoted as follows: and Then the transfer function value at that frequency is Based on this, draw The amplitude-frequency and phase-frequency characteristics. For combined parameter measurement experiment 1, the sinusoidal signal and the voltage component in the dq coordinate system were processed by Fast Fourier Transform, and the complex spectrum values ​​of the three components at the applied signal frequency were extracted, denoted as follows: , and ,based on and The voltage-dq axis transfer function is obtained by calculating the ratio. ,based on and The ratio and combined The voltage-voltage transfer function is derived. The amplitude-frequency and phase-frequency characteristics of the two transfer functions were plotted simultaneously. For the combined parameter measurement experiment 2 and the reactive power characteristic parameter measurement experiment, the sinusoidal signal and the three-phase current were processed by Fast Fourier Transform, respectively, and their complex spectrum values ​​at the applied signal frequency were extracted. The results were then calculated. and And plot the corresponding amplitude frequency response curve and phase frequency response curve.

[0053] S3, based on the amplitude-frequency characteristic inflection point and low-frequency gain step-by-step decoupling control parameters corresponding to each experimental scenario, eliminates the multi-parameter coupling effect through independent experimental conditions of open circuit or short circuit conditions; accurately identifies the power loop, voltage loop, filtering link, virtual impedance and reactive power control related equivalent parameters.

[0054] Furthermore, the step-by-step decoupling control parameters in step S3 are specifically as follows: Based on the transfer functions obtained in step S2, the corresponding amplitude-frequency characteristic curves and phase-frequency characteristic curves are plotted. By extracting the low-frequency amplitude and inflection point frequency of the amplitude-frequency characteristic curves, and combining the mathematical model relationships corresponding to each experiment with the decoupling effect of independent open-circuit and short-circuit conditions, the multi-parameter coupling effect is eliminated, and the correlation coefficient of the power loop, the control parameters of the voltage loop, the parameters of the filter loop, and the related parameters of the virtual impedance are calculated respectively.

[0055] In this embodiment, the active power characteristic experiment is determined by the value of the amplitude-frequency characteristic in the low-frequency band and the inflection point frequency. and Experiment 1 on combined parameter measurement was conducted. Determining the combination parameters based on amplitude-frequency characteristics , , ,pass The amplitude-frequency characteristics yield the combined parameters , Experiment 2 on combined parameter measurement was conducted. The amplitude-frequency characteristics are obtained , By combining the results of Experiment 1 with the combined parameter measurement, all voltage and current loop control parameters are obtained; and By subtracting the amplitude-frequency response curves, we obtain Its amplitude-frequency characteristics can be obtained from its amplitude-frequency characteristics. and The specific value to be taken.

[0056] S4. Map the identified equivalent parameters to the physical characteristics of the synchronous machine equivalent model, establish a dynamic model including rotor motion equation parameters, voltage controller parameters and reactive power controller parameters, output the dynamic model and the corresponding identified parameters, and realize the transient stability analysis and control optimization of the power system.

[0057] In this embodiment, the identified power loop correlation coefficient , Corresponding synchronous machine rotor motion equation parameters, voltage loop control parameters , Corresponding voltage controller parameters, reactive power loop correlation coefficient , Corresponding reactive power controller parameters, filter circuit parameters, and virtual impedance parameters , , The relevant electrical parameters of the equivalent model of the synchronous machine are mapped according to the physical characteristics of the equivalent model to construct a complete dynamic model. This model can be directly used for power system transient response modeling and stability analysis, providing a quantitative basis for subsequent control optimization.

[0058] Example 2 This invention also provides a parameter identification device for a grid-type converter based on its static frequency response, such as... Figure 4 As shown, the device 10 includes: The disturbance application and data acquisition module 100 is used to apply a controllable small disturbance signal to the control input interface when the grid-type converter is in static steady-state operation. By adjusting the combined boundary conditions of the active power reference command, reactive power reference command and voltage reference value, it acquires the port voltage and current response data under the corresponding experimental scenarios. The experimental scenarios include active power characteristic parameter measurement experiment, combined parameter measurement experiment 1, combined parameter measurement experiment 2 and reactive power characteristic parameter measurement experiment. The frequency domain characteristic analysis module 200 is used to perform fast Fourier transform processing on the acquired port voltage and current response data, extract the complex spectrum values ​​of the disturbance signal and response data, and calculate the amplitude frequency characteristics and phase frequency characteristics of the target transfer function based on the spectrum ratio. The step-by-step decoupling parameter identification module 300 is used to decouple the control parameters step by step according to the amplitude-frequency characteristic inflection point and low-frequency gain under each experimental scenario. It eliminates the influence of multi-parameter coupling through independent experimental conditions of open circuit or short circuit conditions, and identifies the equivalent parameters of the power loop, voltage loop and reactive power loop respectively. The equivalent model construction module 400 is used to map the identified control parameters to the physical characteristics of the synchronous machine equivalent model and establish a dynamic model that includes rotor motion equation parameters, voltage controller parameters and reactive power controller parameters.

[0059] Example 3 To implement the methods of the above embodiments, the present invention also provides a computer device, which includes a memory and a processor; wherein the processor runs a program corresponding to the executable program code by reading executable program code stored in the memory, so as to implement the various steps of the methods described above.

[0060] Example 4 To implement the above embodiments, this application also proposes a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the method described in the foregoing embodiments.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0062] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. 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.

[0063] 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 invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

Claims

1. A method for parameter identification of a grid-type converter based on stationary frequency response, characterized in that, Includes the following steps: S1. Under the static steady-state operation of the grid-type converter, a controllable small disturbance signal is applied to the control input interface. By adjusting the combined boundary conditions of the active power reference command, reactive power reference command, and voltage reference value, the port voltage and current response data under the corresponding experimental scenarios are obtained respectively. Among them, the experimental scenarios include active power characteristic parameter measurement experiment, combined parameter measurement experiment 1, combined parameter measurement experiment 2, and reactive power characteristic parameter measurement experiment. S2, Fast Fourier Transform is performed on the port voltage and current response data collected in each experimental scenario to extract the complex spectrum values ​​of the disturbance signal and response data in each experimental scenario. According to the target transfer function type preset for each experiment, the amplitude frequency characteristics and phase frequency characteristics of the corresponding transfer function are calculated by the ratio of the complex spectrum values, providing data support for subsequent parameter decoupling. S3, based on the amplitude-frequency characteristic inflection point and low-frequency gain step-by-step decoupling control parameters corresponding to each experimental scenario, eliminates the multi-parameter coupling effect through independent experimental conditions of open circuit or short circuit conditions; accurately identifies the power loop, voltage loop, filtering link, virtual impedance and reactive power control related equivalent parameters; S4. Map the identified equivalent parameters to the physical characteristics of the synchronous machine equivalent model, establish a dynamic model including rotor motion equation parameters, voltage controller parameters and reactive power controller parameters, output the dynamic model and the corresponding identified parameters, and realize the transient stability analysis and control optimization of the power system.

2. The method according to claim 1, characterized in that, The active power characteristic parameter measurement experiment specifically includes: The control grid-type converter port is in an open circuit state, the reactive power reference command is set to 0, and the active power reference command is set to a sinusoidal signal with a variable frequency superimposed near 0. The frequency value of the sinusoidal signal covers the inflection point frequency band of the target transfer function. A phase-locked loop is used to detect the angular frequency of the port voltage at the converter output port. Angular frequency response data is obtained under active power reference command values ​​at different frequencies. Fast Fourier Transform (FFT) processing is performed on the sinusoidal signal and angular frequency response data respectively, and the complex spectrum values ​​of the two at the applied signal frequency are extracted. The transfer function is calculated based on the ratio of the complex spectrum values. .

3. The method according to claim 1, characterized in that, The combined parameter measurement experiment 1 specifically includes: With the control grid-type converter port in an open-circuit state, the active power reference command and reactive power reference command are set to 0, and the voltage reference value is... The method is to superimpose a sinusoidal signal with a variable frequency onto a constant value, wherein the frequency of the sinusoidal signal covers the inflection point frequency band of the target transfer function; The three-phase voltage at the converter output port is acquired. A Park transform is performed on the three-phase voltage using the integral angle at the reference frequency as a reference, yielding the voltage components in the dq coordinate system. Fast Fourier Transforms are then performed on the sinusoidal signal and the two voltage components in the dq coordinate system, respectively, to extract the complex spectrum values ​​of the three components at the applied signal frequency, denoted as follows: , and ,based on and The voltage-dq axis transfer function is obtained by calculating the ratio. ,based on and The ratio and combined The voltage-voltage transfer function is derived. .

4. The method according to claim 1, characterized in that, The combined parameter measurement experiment 2 specifically includes: With the control grid-type converter port in a short-circuit state, the active power reference command and reactive power reference command are set to 0, and the voltage reference value is... The system is configured to superimpose a variable frequency sine wave onto a base of 0, wherein the frequency values ​​of the sine wave cover the inflection point frequency band of the target transfer function. The three-phase current at the converter output port is collected. Fast Fourier Transform (FFT) is performed on both the sinusoidal signal and the three-phase current to extract their complex spectral values ​​at the applied signal frequency. The voltage-current transfer function is calculated based on the ratio of these complex spectral values. .

5. The method according to claim 1, characterized in that, The reactive power characteristic parameter measurement experiment specifically includes: The control grid-type converter port is in a short-circuit state, the active power reference command is set to 0, the voltage reference value is set to 0, and the reactive power reference command is set to a sinusoidal signal with variable frequency superimposed on 0. The frequency value of the sinusoidal signal covers the inflection point frequency band of the target transfer function. The three-phase current at the converter output port is collected. Fast Fourier Transform (FFT) is performed on both the sinusoidal signal and the three-phase current to extract their complex spectral values ​​at the applied signal frequency. The reactive-current transfer function is calculated based on the ratio of these complex spectral values. .

6. The method according to claim 1, characterized in that, The step-by-step decoupling control parameters in step S3 are as follows: Based on the transfer functions obtained in step S2, the corresponding amplitude-frequency characteristic curves and phase-frequency characteristic curves are plotted. By extracting the low-frequency amplitude and inflection point frequency of the amplitude-frequency characteristic curves, and combining the mathematical model relationships corresponding to each experiment with the decoupling effect of independent open-circuit and short-circuit conditions, the multi-parameter coupling effect is eliminated, and the correlation coefficient of the power loop, the control parameters of the voltage loop, the parameters of the filter loop, and the related parameters of the virtual impedance are calculated respectively.

7. A parameter identification device for a grid-type converter based on static frequency response, characterized in that, Includes the following modules: The disturbance application and data acquisition module is used to apply a controllable small disturbance signal to the control input interface under the static steady-state operation of the grid-type converter. By adjusting the combined boundary conditions of the active power reference command, reactive power reference command, and voltage reference value, it acquires the port voltage and current response data under the corresponding experimental scenarios. The experimental scenarios include active power characteristic parameter measurement experiment, combined parameter measurement experiment 1, combined parameter measurement experiment 2, and reactive power characteristic parameter measurement experiment. The frequency domain characteristic analysis module is used to perform fast Fourier transform processing on the port voltage and current response data collected in various experimental scenarios, extract the complex spectrum values ​​of the disturbance signal and response data, and calculate the amplitude frequency characteristics and phase frequency characteristics of the corresponding transfer function by the ratio of the complex spectrum values ​​according to the target transfer function type preset for each experiment, so as to provide data support for subsequent parameter decoupling. The step-by-step decoupling parameter identification module is used to decouple control parameters step by step according to the amplitude-frequency characteristic inflection point and low-frequency gain corresponding to each experimental scenario. It eliminates the influence of multi-parameter coupling through independent experimental conditions of open circuit or short circuit conditions; and accurately identifies the equivalent parameters related to power loop, voltage loop, filtering link, virtual impedance and reactive power control. The equivalent model construction module is used to map the identified equivalent parameters to the physical characteristics of the synchronous machine equivalent model, establish a dynamic model including rotor motion equation parameters, voltage controller parameters and reactive power controller parameters, and output the dynamic model and the corresponding identified parameters to realize power system transient stability analysis and control optimization.

8. A computer device, characterized in that, Including processor and memory; The processor reads the executable program code stored in the memory to run the program corresponding to the executable program code, so as to implement the grid-type converter parameter identification method based on static frequency response as described in any one of claims 1-6.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements a method for identifying parameters of a grid-type converter based on static frequency response as described in any one of claims 1-6.

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