Impedance automatic measurement method of power electronic converter based on real-time simulation platform

Abstract

The application discloses a kind of impedance automation measurement methods of power electronic converter based on real-time simulation platform, including in simulation model, disturbance injection module, data acquisition module, computing flow or time-domain simulation obtains steady state operating point;In disturbance injection module, the parameter that needs to be measured is determined;According to the starting time of measurement, the starting time of the recording wave of data acquisition module in real-time simulation platform, real-time simulation step, sampling factor, storage file size and storage file are determined, and according to the starting time of measurement, the duration of each frequency disturbance, disturbance interval waiting time, the total frequency number of frequency sequence, the total duration of real-time simulation is determined;Injection disturbance, and the voltage and current data set of measured port are obtained;The total frequency number of frequency sequence is calculated impedance value, and full-band impedance characteristic curve is generated.According to the measurement method disclosed in the application, the impedance scanning efficiency is improved, and the new energy equipment impedance is quickly and accurately obtained.

Description

Technical Field

[0001] This invention belongs to the field of power electronic converter system measurement technology, specifically relating to an automated impedance measurement method for power electronic converters based on a real-time simulation platform. Background Technology

[0002] In the design and analysis of power electronic converter systems, impedance characteristics are a key indicator reflecting the system's dynamic response and stability. Traditional impedance measurement methods have the following limitations: low automation, requiring manual frequency switching and data recording, which is cumbersome and inefficient, and makes it difficult to achieve wide-band measurements; limited disturbance modes, often using a single dq coordinate system or sequence component disturbances, which cannot adapt to the different disturbance injection requirements of converter systems with different topologies; poor synchronization, with insufficient synchronization accuracy between disturbance injection and data acquisition, easily introducing measurement errors; and low integration, making it difficult to integrate with real-time simulation platforms and failing to meet the needs of closed-loop testing and dynamic analysis.

[0003] Real-time simulation platforms are widely used in power electronic system testing due to their high precision and real-time performance. However, existing impedance measurement methods based on real-time simulation platforms are mostly semi-automated, lacking a fully automated solution that supports multiple perturbation modes. Therefore, designing a highly automated impedance measurement method that supports multiple perturbation modes is of great significance. Summary of the Invention

[0004] To address the shortcomings and improvement needs of existing technologies, this invention provides an automated impedance measurement method for power electronic converters based on a real-time simulation platform. The purpose is to improve impedance scanning efficiency and achieve rapid and accurate acquisition of impedance for new energy equipment by integrating real-time simulation with an automated impedance measurement method.

[0005] To achieve the above objectives, according to one aspect of the present invention, an automated impedance measurement method for a power electronic converter based on a real-time simulation platform is provided, comprising the following steps:

[0006] S1: Build a simulation model of the power electronic system under test on a real-time simulation platform. Add a disturbance injection module and a data acquisition module to the simulation model. The disturbance injection module supports two modes: dq disturbance and sequence disturbance. Based on the topology and operation mode of the power electronic system under test, calculate the power flow or time domain simulation to obtain the steady-state operating point of the power electronic system under test. The steady-state operating point information includes the steady-state operating equilibrium point of the power electronic system under test and the steady-state phase angle of the measured port.

[0007] S2: In the disturbance injection module, determine the parameters to be measured, including: the frequency sequence range of the preset impedance measurement, the total number of frequencies in the frequency sequence, the amplitude of the injected disturbance, the duration of each frequency disturbance, the disturbance interval waiting time, and the measurement start time;

[0008] S3: Determine the start time of waveform recording, real-time simulation step size, sampling factor, storage file size and storage file of the data acquisition module in the real-time simulation platform based on the measurement start time, and determine the total real-time simulation duration based on the measurement start time, the duration of each frequency disturbance, the disturbance interval waiting time and the total number of frequencies in the frequency sequence;

[0009] S4: Inject disturbances and acquire the voltage and current dataset of the measured port in the power electronic system under test, wherein the disturbances include voltage disturbances or current disturbances;

[0010] S5: Based on the voltage and current dataset of the port under test, calculate the impedance value of the total number of frequencies in the frequency sequence in step S2, and generate the full-band impedance characteristic curve.

[0011] In general, the technical solution conceived in this invention can achieve the following beneficial effects:

[0012] By integrating a real-time simulation platform with an automatic impedance measurement method, the efficiency of impedance scanning is improved, enabling rapid and accurate acquisition of the impedance of new energy equipment. It systematically solves the inherent shortcomings of traditional methods in terms of automation, disturbance modes, measurement efficiency, and accuracy, possessing excellent versatility and can be widely applied to impedance characteristic analysis of various power electronic converter systems. Attached Figure Description

[0013] Figure 1 The diagram shown is a flowchart of an automated impedance measurement method for a power electronic converter based on a real-time simulation platform, according to an embodiment of the present invention.

[0014] Figure 2 The diagram shown is a schematic representation of a power electronic system under test with voltage and current disturbances according to an embodiment of the present invention.

[0015] Figure 3 The diagram shown is a real-time simulation structure block diagram of an automated impedance measurement method provided according to an embodiment of the present invention.

[0016] Figure 4 The diagram shown illustrates different perturbation mode injection selections according to an embodiment of the present invention.

[0017] Figure 5 The figure shown is a power response waveform of the power electronic system under test after real-time simulation of disturbance injection according to an embodiment of the present invention.

[0018] Figure 6 The figure shown is a comparison of impedance data obtained by Fourier analysis of real-time simulation data of the power electronic system under test according to an embodiment of the present invention and the results of the theoretical model. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0020] In this invention, the terms "first," "second," etc. (if present) in the invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0021] This invention discloses an automated impedance measurement method for power electronic converters based on a real-time simulation platform, such as... Figure 1 As shown. Figure 2 The diagram shown is a schematic representation of a power electronic system under test with voltage and current disturbances according to an embodiment of the present invention. Figure 2 The invention includes a power electronic system under test. The method disclosed in this invention is used to measure the impedance of a power electronic converter in the power electronic system under test. Specifically, a disturbance module is set in the power electronic system under test. The disturbance module specifically includes voltage disturbance or current disturbance. This invention achieves automated impedance measurement of the power electronic converter by adding a disturbance module between the coupling port of the power electronic system under test and the power grid, and based on a real-time simulation platform. This is specifically performed through the following method: Figure 1 As shown:

[0022] S1: Build a simulation model of the power electronic system under test on a real-time simulation platform. Add a disturbance injection module and a data acquisition module to the simulation model. The disturbance injection module supports two modes: dq coordinate system disturbance and sequence disturbance. Based on the topology and operating mode of the power electronic system under test, calculate the power flow or time-domain simulation to obtain the steady-state operating point of the power electronic system under test. The steady-state operating point information includes the steady-state operating equilibrium point of the power electronic system under test and the steady-state phase angle of the measured port. It should be noted that this steady-state operating point is used for subsequent theoretical verification and determines the steady-state phase angle of the measured port for coordinate system settings of the disturbance injection module.

[0023] Specifically, regarding the setting of the global order coordinate system under the order disturbance coordinate system, the global order coordinate system is set by converting the steady-state phase angle into the corresponding time interval. During data acquisition, the global order coordinate system is set by shifting forward the response time interval at time points that are integer multiples of the fundamental period. The calculation method for the time interval is as follows:

[0024]

[0025] Where Δ θ The steady-state phase angle of the port under test. T Δ The time interval corresponding to the steady-state phase angle of the port under test. f 0 represents the steady-state fundamental frequency. If it is necessary to observe the port characteristics of the local sequence coordinate system, that is, when collecting the measured data, it is only necessary to collect data at time points that are integer multiples of the fundamental frequency period.

[0026] Regarding the setup of the global dq coordinate system under the dq disturbance coordinate system, the phase angle of the global coordinate system of the Park transform is obtained by integrating the steady-state fundamental angular frequency to obtain the grid phase. θ 0. To observe the characteristics of the local dq coordinate system port, it is necessary to measure the steady-state power angle of the local bus port, determine the steady-state phase angle difference between the local bus port and the main grid port through a phase-locked loop, and obtain the steady-state power angle. Finally, the phase angle of the global grid coordinate system is... θ 0 plus steady-state work angle This will give you the phase angle corresponding to the local dq coordinate system port. θ dq , θ dq The expression is:

[0027]

[0028] in, θ dq This represents the phase angle corresponding to the port in the dq coordinate system. θ 0 represents the phase angle in the global coordinate system of the power grid. θ 0, This indicates the steady-state power angle of the local bus port.

[0029] S2: In the disturbance injection module, determine the parameters to be measured, including: the preset impedance measurement frequency sequence range and the total number of frequencies in the frequency sequence, the amplitude of the injected disturbance, the duration of each frequency disturbance, the disturbance interval waiting time, and the measurement start time; specifically, such as... Figure 3The diagram shows the real-time simulation structure block diagram of the impedance scanning algorithm applied in this invention, where sm_control is the controller module, ss_mainpart is the overall circuit topology, and sc_gui is the oscilloscope display module of the real-time simulation platform. Specifically, through... Figure 2 The ports of the power electronic system under test shown are... Figure 2 A disturbance injection module is introduced into the coupling port, and relevant measurement parameters are preset, including the frequency sequence range of the preset impedance measurement, the amplitude of the disturbance signal, the duration of each frequency disturbance, the disturbance interval waiting time, and the measurement start time.

[0030] It should be noted that the frequency sequence range for preset impedance measurement is generated through a linear or logarithmic distribution, covering the measurement frequency band from the starting frequency to the ending frequency.

[0031]

[0032] in f series This represents a preset frequency sequence. f start The starting frequency point of the preset frequency sequence, f end The end frequency point of the preset frequency sequence, f num This represents the total number of points in the preset frequency sequence. linspace indicates that the frequency sequence follows a linear distribution, and logspace indicates that the frequency sequence follows a log distribution.

[0033] Determining the amplitude of a disturbance signal requires considering the disturbance injection mode, the system's rated capacity, rated voltage, and the ratio of the injected disturbance amplitude to the total amplitude. The system's rated capacity and rated voltage level are used to calculate the amplitudes of the rated voltage and rated current. Specifically, when the injected disturbance is a voltage disturbance, the amplitude of the rated voltage is calculated using the following formula:

[0034]

[0035] When the injected disturbance is a current disturbance, the magnitude of the rated current is calculated using the following formula:

[0036]

[0037] in, S nom Indicates the rated capacity of the power electronic system under test. U nom This indicates the rated line voltage at the port of the power electronic system under test. U phnom_mag Indicates the rated phase voltage amplitude. I phnom_magThis indicates the rated phase current amplitude.

[0038] Furthermore, the duration of each frequency disturbance, the disturbance interval waiting time, and the measurement start time are set, and the total real-time simulation duration is determined based on the above times to reduce unnecessary data acquisition. Specifically, the total simulation duration is calculated as follows:

[0039]

[0040] T sim This indicates the total duration of the real-time simulation. T start This indicates the measurement start time, i.e., the time when the disturbance begins to be injected. T scan This indicates the duration of each frequency perturbation. T wait This indicates the waiting time between disturbances. The total number of frequencies in a frequency sequence.

[0041] S3: Determine the start time of waveform recording, real-time simulation step size, sampling factor, storage file size, and storage file for the data acquisition module in the real-time simulation platform based on the measurement start time. Also, determine the total real-time simulation duration based on the measurement start time, the duration of each frequency disturbance, the disturbance interval waiting time, and the total number of frequencies in the frequency sequence. Specifically, first, connect the waveforms to be recorded to the data acquisition module of the real-time simulation platform according to the number of channels. Pre-set the waveform recording start time in the data acquisition module of the real-time simulation device to determine the starting moment for recording waveform data. When the real-time simulation time is greater than the waveform recording start time, waveform data recording begins. The waveform recording start time refers to the start time of data acquisition. Calculate the file storage size after waveform recording by setting the real-time simulation step size and sampling factor. The file size calculation method is as follows:

[0042]

[0043] in, T sample This indicates the real-time simulation step size, df represents the sampling factor (how many real-time simulation steps are used to sample data points), and channels represents the total number of waveform channels to be recorded. Filesize represents the final storage data size in bytes. After the waveform recording is complete, set the storage file name.

[0044] S4: Inject disturbances and acquire the voltage and current datasets of the measured port in the power electronic system under test. The disturbances include voltage disturbances or current disturbances. Specifically, start the real-time simulation platform. When the simulation time reaches the measurement start time and the enable signal is valid, the disturbance injection module enters the automated measurement process. The disturbance injection module realizes automated impedance scanning through state machine control. For each frequency point, it executes the following in sequence: Mode 1 Disturbance Injection State A1, Disturbance Interval Waiting State A2, Mode 2 Disturbance Injection State A3, Interval Waiting State A4, Switch to the Next Frequency Point State A5, until all frequency points are scanned. The state not in A1~A5 is called the idle state A0. Mode 1 includes dq mode 1 and sequence mode 1, and Mode 2 includes dq mode 2 and sequence mode 2.

[0045] The overall state machine control logic is as follows:

[0046] When the state is in idle state A0, the simulation time has not reached the start time or the measurement is completed, and the state remains idle. When the start condition is met, the state is switched to mode 1 disturbance injection state A1.

[0047] When the state is in the mode 1 disturbance injection state A1, the mode 1 disturbance at the current frequency point is continuously injected, and after the preset duration is reached, the state switches to the disturbance interval waiting state A2.

[0048] When the state is in the disturbance interval waiting state A2, the disturbance injection stops, and after waiting for the preset interval time, it switches to the mode 2 disturbance injection state A3.

[0049] When the state is in the mode 2 disturbance injection state A3, the mode 2 disturbance of the current frequency point is continuously injected. After the preset duration is reached, if there is a next frequency point, the state switches to the frequency switching waiting state A4; otherwise, the state returns to the idle state A0 and the measurement is marked as complete.

[0050] When the state is in frequency switching waiting state A4, the perturbation injection stops, and after waiting for a preset interval, it switches to mode 1 perturbation injection state A2 and updates the frequency index to the next frequency point.

[0051] In one optional embodiment of the present invention, a perturbation injection method needs to be configured. The perturbation signal expression is different under different perturbation modes. It should be noted that the perturbation injection method is divided into dq perturbation quantity injection and sequence perturbation quantity injection. When dq perturbation quantity injection is used, the signal expression of dq mode 1 perturbation injection is:

[0052]

[0053] in, f k This indicates the frequency of the currently injected perturbation. fk ∈ f series , y d1 This represents the d-axis perturbation under perturbation injection in dq mode 1. y q1 This represents the q-axis perturbation under perturbation injection in dq mode 1;

[0054] When using dq perturbation injection, the signal expression for dq mode 2 perturbation injection is:

[0055]

[0056] in, y d2 This indicates the d-axis perturbation under perturbation injection in dq mode 2. y q2 This represents the q-axis perturbation under perturbation injection in dq mode 2, and Mag represents the magnitude of the dq perturbation.

[0057] When using ordered perturbation injection, the perturbation expression for ordered mode 1 is:

[0058]

[0059] In this context, the perturbation in sequence mode 1 represents the positive-sequence perturbation, and pha_p, phb_p, and phc_p represent the three phases A, B, and C, respectively. f p This represents the frequency value under positive-sequence perturbation. f p ∈ f series Mag - p represents the amplitude of the disturbance during positive-sequence disturbance. During positive-sequence disturbance:

[0060]

[0061] When using sequence perturbation injection, the signal expression for sequence mode 2 perturbation injection is:

[0062]

[0063] In this context, the perturbation in sequence mode 2 represents the negative sequence perturbation, and pha_n, phb_n, and phc_n represent the three phases A, B, and C, respectively. f n Mag_n represents the negative-sequence frequency, i.e., the frequency value under negative-sequence perturbation, and the magnitude of the perturbation under negative-sequence perturbation. f p The relational expression satisfies:

[0064]

[0065] in, f p Indicates positive sequence frequency. f n Represents the negative sequence frequency, where the phase satisfies the following during negative sequence perturbation:

[0066]

[0067] Once the disturbance mode is configured, real-time simulation is started. When the simulation time reaches the measurement start time and the enable signal is valid, the disturbance injection module enters the automated measurement process and synchronously collects the voltage and current of the power electronic system port after disturbance injection through the preset data acquisition module.

[0068] S5: Based on the voltage and current dataset of the tested port, calculate the impedance value of the total number of frequencies in the frequency sequence from step S2, and generate a full-band impedance characteristic curve. Specifically, the port voltage and port current signal data of the power electronic system response acquired by the data acquisition module after the disturbance is completed are automatically processed. Frequency domain analysis methods are used to process the data. Specifically, by setting the sampling period and Fourier analysis time window, Fourier transform or Fast Fourier Transform (FFT) is performed on the signal sequence within the disturbance injection period corresponding to each frequency point to extract the amplitude and phase information of the fundamental component at the disturbance frequency. The specific operation is as follows:

[0069] S51: Based on the sampling period T sample Determine the sampling rate f sample =1 / T sample .

[0070] S52: Select a Fourier time window. Choose a time period that includes the complete perturbation period as the Fourier analysis time window. If the perturbation frequency is... f k The Fourier analysis window length is set to be an integer multiple of its period, and the following relationship is satisfied:

[0071]

[0072] in, T window This represents the time window for Fourier analysis. N window This indicates the data length corresponding to the Fourier time window. The Fourier frequency resolution is... f window =1 / T window .

[0073] S53: Fourier transform data processing under perturbation frequency: Extracting the perturbation frequency f k The voltage and current sequence data within the lower Fourier time window. When the disturbance is dq, the extracted data are d-axis and q-axis voltages and d-axis and q-axis currents:

[0074]

[0075] in, u d1 ( N window ), u q1 ( N window ), i d1 ( N window ), i q1 ( N window The numbers () represent the port d-axis voltage, q-axis voltage, d-axis current, and q-axis current response data under dq disturbance injection in mode 1, respectively. u d2 ( N window ), u q2 ( N window ), i d2 ( N window ), i q2 ( N window The figures represent the d-axis voltage, q-axis voltage, d-axis current, and q-axis current response data under dq perturbation injection in mode 2, respectively. N 0 indicates the starting point for collecting data points.

[0076] When the disturbance is a sequential disturbance, the extracted data are the phase a voltage and phase a current:

[0077]

[0078] in, u a1 ( N window ), i a1 ( N window The numbers () represent the A-phase port voltage and A-phase port current data under the sequential disturbance injection in Mode 1, respectively. ua2 ( N window ), i a2 ( N window The data represents the A-phase port voltage and A-phase port current under the sequential disturbance injection in mode 2.

[0079] S54: Use Fast Fourier Transform (FFT) to perform spectral analysis on the extracted voltage and current, and extract the amplitude and phase information of the frequency components corresponding to the disturbance frequency, i.e., complex values.

[0080] When the disturbance is a dq disturbance, for u d1 ( N window ), u q1 ( N window ), i d1 ( N window ), i q1 ( N window ), u d2 ( N window ), u q2 ( N window ), i d2 ( N window ), i q2 ( N window Perform Fast Fourier Transform on each:

[0081]

[0082] When the disturbance is an ordered disturbance, for u a1 ( N window ), i a1 ( N window ), u a2 ( N window ), i a2 ( N windowPerform Fast Fourier Transform on each:

[0083]

[0084] S55: Locate the data corresponding to the disturbance frequency point. The extracted frequency point location is:

[0085] When the disturbance is a dq disturbance, we have:

[0086]

[0087] Where, round indicates rounding to the nearest whole number. N f This indicates the location of the frequency point extracted after the FFT transform. Data extraction needs to be performed according to different perturbation modes. At this point, the extracted data at the perturbation frequency represents the port d-axis voltage, q-axis voltage, d-axis current, and q-axis current.

[0088]

[0089] When the disturbance is ordered, the positions corresponding to positive and negative orders are different:

[0090]

[0091] Where, round indicates rounding to the nearest whole number. N f1 This indicates the location of the frequency points extracted from the positive-sequence components after the FFT transform. N f2 This indicates the location of the frequency point extracted from the negative-order component. f p Indicates positive sequence frequency. f n Representing negative-order frequencies, the relation satisfies:

[0092]

[0093] The data extracted at this time are the positive-sequence voltage, negative-sequence voltage, positive-sequence current, and negative-sequence current of phase a at the disturbance frequency. The sequence components at the disturbance frequency are extracted in the following way:

[0094]

[0095] The symbol “*” indicates taking the conjugate of a complex number.

[0096] Finally, the two different perturbation components at the perturbation frequency are extracted to construct second-order voltage and current numerical matrices. The voltage and current matrices are different under different perturbations. Under the sequence perturbation, the voltage and current matrices are constructed as follows:

[0097]

[0098] Under dq perturbation, the voltage and current matrices are constructed as follows:

[0099]

[0100] The impedance / admittance values ​​at each frequency point are calculated using matrix inversion. The calculation method is as follows:

[0101]

[0102] in Z This represents the port impedance matrix of the power electronic system under test. Y This represents the port admittance matrix of the power electronic system under test. When the disturbance is a sequence disturbance... Z Represents the port-order impedance matrix. Y This represents the port-order admittance matrix; when the perturbation is dq, Z Represents the port dq impedance matrix. Y The port dq admittance matrix is ​​represented; both the impedance and admittance matrices are 2x2 complex matrices containing four elements.

[0103] Finally, the impedance matrices at all frequency points across the entire frequency band are integrated into a frequency domain response matrix array.

[0104]

[0105] Finally, the amplitude-frequency and phase-frequency characteristics of the four elements in the impedance matrix are plotted to generate the impedance scanning characteristic curve of the power electronic system under test across the entire frequency band.

[0106] On a real-time simulation platform, such as RTLAB, perform time-domain real-time simulation impedance sweep verification. Figure 5 The waveforms shown are the system response waveforms after the real-time simulation disturbance module is activated and disturbance injection is performed in this invention; cyan represents the active power response waveform, blue represents the frequency value of the real-time injected disturbance, and purple represents the reactive power response waveform. By performing Fourier analysis on the real-time acquired signals, the results of the simulated impedance measurement can be further obtained. Figure 6 This section presents a comparison between impedance data obtained from Fourier analysis of real-time simulation data collected in this invention and the theoretical model. Figure 6 The left figure shows a comparison between the small-signal 2x2 sequence impedance scan data and the theoretical formula results of a converter in a system under test. Figure 6 The right figure shows a comparison between the small-signal 2x2 dq impedance sweep data of a converter in a system under test and the theoretical formula results. It can be observed from the figure that the impedance sweep results are basically consistent with the established impedance model, which verifies the accuracy of the automated measurement method of the present invention.

[0107] This invention presents an automated impedance measurement method for power electronic converters based on a real-time simulation platform and verifies the correctness of the invented algorithm. It solves the problems of low automation, limited perturbation modes, and insufficient efficiency and accuracy in traditional impedance measurement methods, improving impedance measurement efficiency and making it applicable to impedance characteristic analysis of various power electronic converter systems. This invention facilitates the application of impedance measurement in equipment within new energy power systems, contributing to the construction of new power systems.

[0108] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An automated impedance measurement method for power electronic converters based on a real-time simulation platform, characterized in that, Includes the following steps: S1: Build a simulation model of the power electronic system under test on a real-time simulation platform. Add a disturbance injection module and a data acquisition module to the simulation model. The disturbance injection module supports two modes: dq disturbance and sequence disturbance. Based on the topology and operation mode of the power electronic system under test, calculate the power flow or time domain simulation to obtain the steady-state operating point of the power electronic system under test. The steady-state operating point information includes the steady-state operating equilibrium point of the power electronic system under test and the steady-state phase angle of the measured port. S2: In the disturbance injection module, determine the parameters to be measured, including: the frequency sequence range of the preset impedance measurement, the total number of frequencies in the frequency sequence, the amplitude of the injected disturbance, the duration of each frequency disturbance, the disturbance interval waiting time, and the measurement start time; S3: Determine the start time of waveform recording, real-time simulation step size, sampling factor, storage file size and storage file of the data acquisition module in the real-time simulation platform based on the measurement start time, and determine the total real-time simulation duration based on the measurement start time, the duration of each frequency disturbance, the disturbance interval waiting time and the total number of frequencies in the frequency sequence; S4: Inject disturbances and acquire the voltage and current dataset of the measured port in the power electronic system under test. The disturbances include voltage disturbances or current disturbances. The disturbance injection module realizes automatic impedance scanning through state machine control. For each frequency point, it executes the following in sequence: Mode 1 Disturbance Injection State A1, Disturbance Interval Waiting State A2, Mode 2 Disturbance Injection State A3, Interval Waiting State A4, Switch to the Next Frequency Point State A5, until all frequency points are scanned. The state not in A1~A5 is called the idle state A0. Mode 1 includes dq mode 1 and sequence mode 1 respectively, and Mode 2 includes dq mode 2 and sequence mode 2. The state machine control logic is as follows: When the state is in idle state A0, the simulation time has not reached the start time or the measurement is completed, and the state remains idle. When the start condition is met, the state is switched to mode 1 disturbance injection state A1. When the state is in the mode 1 disturbance injection state A1, the mode 1 disturbance at the current frequency point is continuously injected, and after the preset duration is reached, the state switches to the disturbance interval waiting state A2. When the state is in the disturbance interval waiting state A2, the disturbance injection stops, and after waiting for the preset interval time, it switches to the mode 2 disturbance injection state A3. When the state is in the mode 2 disturbance injection state A3, the mode 2 disturbance of the current frequency point is continuously injected. After the preset duration is reached, if there is a next frequency point, the state switches to the frequency switching waiting state A4; otherwise, the state returns to the idle state A0 and the measurement is marked as complete. When the state is in frequency switching waiting state A4, stop the disturbance injection, wait for the preset interval time, and then switch to mode 1 disturbance injection state A2, and update the frequency index to the next frequency point. S5: Based on the voltage and current dataset of the port under test, calculate the impedance value of the total number of frequencies in the frequency sequence in step S2, and generate the full-band impedance characteristic curve.

2. The method for automated impedance measurement of a power electronic converter based on a real-time simulation platform according to claim 1, characterized in that, The steady-state phase angle of the port measured in S1 is used to determine the starting position of the data acquisition point after disturbance injection in different coordinate systems. In the sequence disturbance mode, the global sequence coordinate system is set by moving the response forward at an integer multiple of the fundamental period during data acquisition. The time interval is calculated as follows: in The steady-state phase angle of the port under test. The time interval corresponding to the steady-state phase angle of the port under test. f 0 represents the steady-state fundamental frequency; In dq disturbance mode, the steady-state power angle at the local bus port is measured, and the steady-state phase angle difference between the local bus port and the main grid port is determined through a phase-locked loop to obtain the steady-state power angle. δ represents the phase angle in the global coordinate system of the power grid. θ 0 plus steady-state work angle δ yields the phase angle corresponding to the port in the local dq coordinate system. θ dq , θ dq The expression is: in, θ dq This represents the phase angle corresponding to the port in the dq coordinate system. θ 0 represents the phase angle in the global coordinate system of the power grid. θ 0, δ represents the steady-state power angle of the local bus port.

3. The method for automated impedance measurement of a power electronic converter based on a real-time simulation platform according to claim 1, characterized in that, In S2, the frequency sequence range for preset impedance measurement is generated through a linear or logarithmic distribution, covering the measurement frequency band from the starting frequency to the ending frequency. in f series This represents a preset frequency sequence. f start The starting frequency point of the preset frequency sequence, f end The end frequency point of the preset frequency sequence, f num This represents the total number of points in the preset frequency sequence. linspace indicates that the frequency sequence follows a linear distribution, and logspace indicates that the frequency sequence follows a log distribution.

4. The method for automated impedance measurement of a power electronic converter based on a real-time simulation platform according to claim 1, characterized in that, in: In S2, when the injected disturbance is a voltage disturbance, the amplitude of the rated voltage is calculated using the following formula: When the injected disturbance is a current disturbance, the magnitude of the rated current is calculated using the following formula: in, S nom Indicates the rated capacity of the power electronic system under test. U nom This indicates the rated line voltage at the port of the power electronic system under test. U phnom_mag Indicates the rated phase voltage amplitude. I phnom_mag This indicates the rated phase current amplitude.

5. The method for automated impedance measurement of a power electronic converter based on a real-time simulation platform according to claim 4, characterized in that, in: The amplitude of the injected disturbance is determined in the following way: Where Mag represents the amplitude of the injected perturbation. U pmag To inject the disturbance voltage amplitude, I pmag The value is the amplitude of the injected disturbance current. When the injected disturbance is a voltage disturbance, the amplitude of the disturbance voltage is used as the disturbance amplitude. When the injected disturbance is a current disturbance, the amplitude of the disturbance current is used as the disturbance amplitude.

6. The method for automated impedance measurement of a power electronic converter based on a real-time simulation platform according to claim 1, characterized in that, The formula for calculating the total real-time simulation duration in S2 is as follows: in, T sim This indicates the total duration of the real-time simulation. T start This indicates the measurement start time, i.e., the time when the disturbance begins to be injected. T scan This indicates the duration of each frequency perturbation. T wait This indicates the waiting time between disturbances. The total number of frequencies in a frequency sequence.

7. The method for automated impedance measurement of a power electronic converter based on a real-time simulation platform according to claim 1, characterized in that, These include: The file storage size is calculated using the following expression: in, T sim This indicates the total duration of the real-time simulation. T sample The real-time simulation step size is represented by df, which represents the sampling factor, i.e., how many real-time simulation steps are used to collect data points. The channels represent the total number of waveform channels that need to be recorded. The Filesize represents the final storage data size in bytes.

8. The method for automated impedance measurement of a power electronic converter based on a real-time simulation platform according to claim 1, characterized in that, S4 also includes: Perturbation injection methods are divided into dq perturbation injection and sequential perturbation injection. When dq perturbation injection is used, the signal expression for dq mode 1 perturbation injection is: in, f k This indicates the frequency of the currently injected perturbation. f k ∈ f series , f series This represents a preset frequency sequence. y d1 This indicates the d-axis perturbation under perturbation injection in dq mode 1. y q1 This represents the q-axis perturbation under perturbation injection in dq mode 1; When using dq perturbation injection, the signal expression for dq mode 2 perturbation injection is: in, y d2 This indicates the d-axis perturbation under perturbation injection in dq mode 2. y q2 This represents the q-axis perturbation under perturbation injection in dq mode 2, and Mag represents the magnitude of the dq perturbation. When using ordered perturbation injection, the perturbation expression for ordered mode 1 is: In this context, the perturbation in sequence mode 1 represents the positive-sequence perturbation, and pha_p, phb_p, and phc_p represent the three phases A, B, and C, respectively. f p This represents the frequency value under positive-sequence perturbation. f p ∈ f series Mag_p represents the magnitude of the disturbance during positive-sequence disturbances. During positive-sequence disturbances: When using sequence perturbation injection, the perturbation expression for sequence mode 2 is: In this context, the perturbation in sequence mode 2 represents the negative sequence perturbation, and pha_n, phb_n, and phc_n represent the three phases A, B, and C, respectively. f n This represents the frequency value under negative-sequence perturbation, and Mag_n represents the amplitude of the perturbation under negative-sequence perturbation. f p The relational expression satisfies: in, f p Indicates positive sequence frequency. f n Represents the negative sequence frequency, where the phase satisfies the following during negative sequence perturbation: Once the disturbance mode is configured, real-time simulation is started. When the simulation time reaches the measurement start time and the enable signal is valid, the disturbance injection module enters the automated measurement process and synchronously collects the voltage and current of the power electronic system port after disturbance injection through the preset data acquisition module.

9. The method for automated impedance measurement of a power electronic converter based on a real-time simulation platform according to claim 1, characterized in that, S5 also includes: Set the sampling period and Fourier analysis time window, perform Fourier transform or fast Fourier transform on the signal sequence within the disturbance injection period corresponding to each frequency point, and extract the amplitude and phase information of the fundamental component at the disturbance frequency. Two different disturbance components at the disturbance frequency are extracted, and second-order voltage and current numerical matrices are constructed. The impedance values ​​at each frequency point are calculated by matrix inversion. The impedance parameters of all frequency points in the whole frequency band are integrated into a 2x2 array. The impedance scan characteristic curve of the power electronic system under test in the whole frequency band is generated by plotting.

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