New energy grid-connected hardware-in-loop simulation test method and system

Abstract

The invention discloses a new energy grid-connected hardware-in-loop simulation test method and system, and the method comprises the steps: generating a sinusoidal signal according to a preset signal parameter through an IO precision checking module, calculating the amplitude and frequency errors, and correcting a simulation model through an IO configuration module during the overrun, thereby effectively solving the problems of signal transmission misalignment and large test result fluctuation caused by IO drift. Meanwhile, by means of a test type lookup table module and an expected voltage generation module, a target power grid voltage waveform is automatically generated according to preset fault types, phases and time length parameters, port voltage is adjusted through an IO configuration module, an interaction test with a new energy controller is completed, the fault triggering moment is accurately controlled, and the fault triggering efficiency is improved. And the problem of unreliable test result caused by triggering randomness is avoided. According to the method, IO precision automatic checking and fault voltage waveform automatic generation are realized, the accuracy and consistency of test results are greatly improved, and the new energy grid-connected hardware-in-loop simulation test and comparison efficiency are remarkably improved.

Description

Technical Field

[0001] This application relates to the field of power system simulation technology, and more particularly, to a method and system for new energy grid-connected hardware-in-the-loop simulation test. Background Art

[0002] With the rapid development of the new power system, a large number of new energy power stations such as wind power and photovoltaic power are continuously connected to the power grid, bringing huge challenges to the safe and stable operation of the power system. As a key technology for evaluating the grid connection characteristics of new energy power stations, hardware-in-the-loop real-time simulation is widely used in grid connection test analysis. The existing new energy hardware-in-the-loop simulation system consists of a real-time simulator, an IO interface, and a new energy controller, and is used to simulate the grid connection operation of the power station.

[0003] However, the current test method has significant defects: on the one hand, the test results are extremely vulnerable to the influence of the fault triggering moment. Since the fault triggering conditions cannot be accurately controlled, the results generated by each test are highly random, resulting in obvious differences in the results of multiple tests; on the other hand, the IO interface is prone to drift, and the amplitude and frequency change during the signal transmission process, making the simulation data inaccurate. This not only causes great difficulties in the analysis and summary of the test results, but also greatly reduces the test efficiency. Especially when conducting simulation comparison tests between different simulators, factors such as the uncertainty of the fault triggering moment and IO drift make it necessary for testers to repeatedly conduct tests to verify the results, seriously affecting the progress of the test work, and there is currently no perfect method to solve these problems.

[0004] Therefore, there is an urgent need for a method for new energy grid-connected hardware-in-the-loop simulation test to solve the defects of the existing technology. Summary of the Invention

[0005] This application provides a method and system for new energy grid-connected hardware-in-the-loop simulation test. By calculating and correcting the amplitude and frequency errors through an IO accuracy calibration module to solve the IO drift problem, and using a test type lookup table module and an expected voltage generation module to automatically generate the target grid voltage waveform according to preset parameters to accurately control the fault triggering moment, the accuracy and consistency of the test results are improved, the efficiency of new energy grid-connected hardware-in-the-loop simulation test and comparison is significantly increased, and the defects of the existing technology are effectively overcome.

[0006] A method for new energy grid-connected hardware-in-the-loop simulation test, which is applied to a new energy grid-connected hardware-in-the-loop simulation test system including a test type lookup table module, an expected voltage generation module, an IO accuracy calibration module, an IO configuration module, and an IO interface. The method includes:

[0007] The IO precision verification module step - generates a number of sine signals that meet the signal frequency range and signal amplitude range based on a preset minimum signal frequency, frequency step value, minimum signal amplitude, and amplitude step value, outputs them through the IO interface, measures the corresponding measured amplitudes and measured frequencies, and calculates each amplitude error and each frequency error;

[0008] If there is an amplitude error or a frequency error exceeding the allowable threshold, calculate a correction coefficient based on the amplitude errors and the frequency errors, and correct the simulation model through the IO configuration module;

[0009] The test type lookup table module loads preset fault type, fault phase, and fault duration parameters and transfers them to the expected voltage generation module;

[0010] The expected voltage generation module generates a target grid voltage waveform based on the fault type, fault phase, and fault duration parameters;

[0011] The IO configuration module adjusts the port voltage of the simulation model to the target grid voltage waveform and interacts with the new - energy controller through the IO interface to complete the grid - connection simulation test.

[0012] Optionally, the generation method of the number of sine signals is as follows:

[0013] Taking the minimum signal frequency as the starting frequency, gradually increase the signal frequency by the frequency step value until reaching the sum of the signal frequency range and the minimum signal frequency;

[0014] Taking the minimum signal amplitude as the starting amplitude, gradually increase the signal amplitude by the amplitude step value until reaching the sum of the signal amplitude range and the minimum signal amplitude;

[0015] After each frequency and amplitude step adjustment, generate a corresponding sine signal based on the current frequency and current amplitude.

[0016] Optionally, for any sine signal generated by stepping, the formulas for calculating the amplitude error and the frequency error are:

[0017]

[0018]

[0019] Where, is the amplitude error, is the current amplitude, is the measured amplitude, is the frequency error, is the current frequency, is the measured frequency.

[0020] Optionally, calculating a correction coefficient according to the respective amplitude errors and the respective frequency errors includes:

[0021] Determining an average amplitude error and an average frequency error according to the respective amplitude errors and the respective frequency errors;

[0022] Calculating a correction coefficient based on the average amplitude error and the average frequency error;

[0023] The calculation formula of the correction coefficient is:

[0024]

[0025]

[0026] Wherein, and are correction coefficients for adjusting the amplitude and frequency of the signal respectively, is the average amplitude error, is the average frequency error.

[0027] Optionally, generating a target grid voltage waveform based on the fault type, fault phase and fault duration parameters includes:

[0028] Determining an output fault phase voltage waveform according to the fault type, and outputting a complementary phase voltage waveform through a complementary output port;

[0029] Determining a fault starting moment based on the fault phase and the zero phase point of the detected grid voltage of phase A;

[0030] Generating a voltage amplitude step signal with a corresponding drop depth according to the fault type, the fault starting moment and the fault duration;

[0031] Multiplying the voltage amplitude step signal by the fault phase voltage waveform to generate a fault phase corrected voltage waveform, and then combining it with the complementary phase voltage waveform to form a target grid voltage waveform.

[0032] A new energy grid-connected hardware-in-the-loop simulation test system includes a test type look-up table module, an expected voltage generation module, an IO accuracy verification module, an IO configuration module, and an IO interface;

[0033] The test type look-up table module is used to store and load preset fault type, fault phase and fault duration parameters;

[0034] The expected voltage generation module is used to generate a target grid voltage waveform based on the fault type, fault phase and fault duration parameters;

[0035] The IO accuracy verification module is used to step - generate and output a number of sine signals that meet the signal frequency range and signal amplitude range according to the preset minimum signal frequency, frequency step value, minimum signal amplitude, and amplitude step value, measure the measured amplitude and measured frequency of the IO interface, and calculate each amplitude error and each frequency error;

[0036] The IO configuration module is used to compensate the signal amplitude and frequency of the simulation model based on the correction coefficient, and adjust the port voltage of the simulation model to the target grid voltage waveform;

[0037] The IO interface is connected to the new - energy controller as an interaction interface to complete the grid - connection simulation test.

[0038] Optionally, the desired voltage generation module includes:

[0039] The fault - phase selection sub - module selects and outputs the fault - phase voltage waveform according to the fault type, and outputs the complementary - phase voltage waveform through the complementary output port;

[0040] The zero - crossing detection sub - module is used to detect the zero - phase point of the A - phase grid voltage, and determine the fault starting moment according to the fault phase and the zero - phase point;

[0041] The low - and - high voltage - dip sub - module is used to generate a voltage - amplitude step signal with a corresponding dip depth according to the fault type, the fault starting moment, and the fault duration;

[0042] The signal combination sub - module is used to multiply the voltage - amplitude step signal by the fault - phase voltage waveform to generate a fault - phase corrected voltage waveform, and then combine it with the complementary - phase voltage waveform to form the target grid voltage waveform.

[0043] Optionally, the complementary output port of the fault - phase selection sub - module outputs three - phase voltage waveforms when there is no fault, outputs the corresponding non - fault - phase voltage waveforms in the case of single - phase or two - phase faults, and outputs a zero signal in the case of three - phase faults.

[0044] Optionally, the voltage - amplitude step signal generated by the low - and - high voltage - dip sub - module is synchronized with the fault starting moment output by the zero - crossing detection sub - module, so that the voltage - amplitude dip depth matches the fault type and the fault duration.

[0045] Optionally, the target grid voltage waveform generated by the desired voltage generation module drives the simulation model in the IO configuration module, so that the port voltage of the simulation model is consistent with the target grid voltage waveform.

[0046] As can be seen from the above technical solutions, a new energy grid-connected hardware-in-the-loop simulation test method and system provided by the embodiments of the present application effectively avoid the defects of the prior art through the coordinated operation of multiple modules. The present application utilizes an IO accuracy verification module to stepwise generate a sine signal based on preset signal parameters, calculates the measured amplitude and frequency errors compared with the preset values, and corrects the simulation model using the IO configuration module when the error exceeds the limit. This process precisely solves the problems in the prior art where signal transmission is inaccurate and test results vary significantly due to IO drift. At the same time, with the help of the test type lookup table module and the expected voltage generation module, it is possible to automatically generate the target grid voltage waveform according to the preset fault type, fault phase, and fault duration parameters, and complete the test by adjusting the port voltage of the simulation model and interacting with the new energy controller through the IO configuration module, thus achieving precise control of the fault triggering moment and avoiding the problem of unreliable test results caused by the randomness of fault triggering. The present application realizes the automatic verification of IO accuracy and the automatic generation of fault voltage waveforms, greatly improving the accuracy and consistency of test results, significantly enhancing the efficiency of new energy grid-connected hardware-in-the-loop simulation tests and comparisons, and effectively overcoming the deficiencies of the prior art. Description of the Drawings

[0047] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings described below are only the embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the provided drawings.

[0048] Figure 1 It is a structural diagram of a new energy grid-connected hardware-in-the-loop simulation test system disclosed in the embodiments of the present application;

[0049] Figure 2 It is a flowchart of a new energy grid-connected hardware-in-the-loop simulation test method disclosed in the embodiments of the present application;

[0050] Figure 3 It is a structural diagram of an expected voltage generation module disclosed in the embodiments of the present application. Detailed Embodiments

[0051] The following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of them. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0052] Figure 1The figure shows the structure diagram of a hardware-in-the-loop simulation test system for new energy grid connection according to an embodiment of the present application.

[0053] The present application can be applied to a hardware-in-the-loop simulation test system for new energy grid connection, as shown in Figure 1, which includes a test type look-up table module 101, an expected voltage generation module 102, an IO accuracy verification module 103, an IO configuration module 104, and an IO interface 105.

[0054] Specifically, the test type look-up table module 101 stores key parameters such as fault type (FltType), fault phase (θ), and fault duration (Tf). Its function is to provide preset test condition information for the entire test. By passing these parameters to the expected voltage generation module 102, it determines the relevant characteristics of the target grid voltage waveform required for the test.

[0055] The expected voltage generation module 102 generates a target grid voltage waveform (Vgrid) based on the parameters received from the test type look-up table module 101. This voltage waveform is a key signal for simulating the grid voltage situation during the new energy grid connection process and provides a basic voltage signal for subsequent simulation tests.

[0056] The IO accuracy verification module 103 is mainly responsible for detecting and calibrating the IO accuracy of the system. Based on parameters such as the preset minimum signal frequency, frequency step value, minimum signal amplitude, and amplitude step value, it stepwise generates a number of sine signals that meet a specific signal frequency range and signal amplitude range. These sine signals are output through the IO interface 105, and the corresponding measured amplitude and measured frequency are measured. Then, the amplitude error and frequency error of each are calculated. If there is a situation where the amplitude error or frequency error exceeds the allowable threshold, the IO accuracy verification module 103 will obtain a correction coefficient based on the calculated amplitude errors and frequency errors of each and pass it to the IO configuration module 104.

[0057] The IO configuration module 104 plays an important role of connecting the upper and lower parts and configuring and adjusting in the system. On the one hand, when receiving the correction coefficient transmitted by the IO accuracy verification module 103, it corrects the simulation model according to the correction coefficient to compensate for signal deviations caused by factors such as IO drift, ensuring the accuracy of system signal transmission. On the other hand, when the system is in the grid connection test mode (Mode = 1), it receives the target grid voltage waveform (Vgrid) from the expected voltage generation module 102, adjusts the port voltage of the simulation model to the target grid voltage waveform, and then interacts with the new energy controller through the IO interface 105 to complete the grid connection simulation test.

[0058] The IO interface 105 is a bridge for the entire system to interact with the new energy controller in terms of data. During the IO accuracy calibration process, it is used to output the sine signals generated by the IO accuracy calibration module 103 and feedback the measured signal amplitude and frequency data. During the grid connection test process, it transmits the port voltage signal adjusted by the IO configuration module 104 to the new energy controller and also receives relevant feedback signals from the new energy controller to achieve data intercommunication between the two and ensure the smooth progress of the simulation test.

[0059] Next, the solution of this application will be introduced. The following technical solution is proposed in this application. Please refer to the following text for details.

[0060] Figure 2 It is a flowchart of a method for new energy grid-connected hardware-in-the-loop simulation test disclosed in an embodiment of this application.

[0061] As Figure 2 shown, the method may include:

[0062] Step S1: Based on a preset signal minimum frequency, frequency step value, signal minimum amplitude, and amplitude step value, the IO accuracy calibration module stepwise generates a number of sine signals that meet the signal frequency range and signal amplitude range, outputs them through the IO interface, measures the corresponding measured amplitudes and measured frequencies, and calculates each amplitude error and each frequency error.

[0063] Specifically, the IO accuracy calibration module is responsible for accurately detecting the system IO accuracy. First, a series of key parameters need to be preset, namely, the signal minimum frequency, which determines the starting reference for frequency scanning; the frequency step value, which is used to specify the amplitude of each frequency increase; the signal minimum amplitude, which is the numerical basis for the start of amplitude scanning; and the amplitude step value, which determines the step size of amplitude increase. Based on these preset parameters, the IO accuracy calibration module stepwise generates a number of sine signals that cover the preset signal frequency range and signal amplitude range.

[0064] The generated sine signals are output through the IO interface. While outputting, a professional measuring device is used to obtain the corresponding measured amplitude and measured frequency. Here, the measured amplitude reflects the difference between the actual output intensity of the signal and the theoretical value, and the measured frequency reflects the deviation between the actual oscillation frequency of the signal and the theoretical value.

[0065] After obtaining the measured data, various amplitude errors and frequency errors are calculated through precise mathematical calculations. The amplitude error can intuitively show the output deviation degree of the signal in terms of amplitude, while the frequency error can reflect the output deviation of the signal in terms of frequency. Through the calculation and analysis of these errors, the accuracy status of the IO interface during signal transmission can be accurately grasped, providing key data support for subsequent targeted correction of the system to ensure the accuracy and reliability of signal transmission in the entire new energy grid-connected hardware-in-the-loop simulation test system.

[0066] The generation method of the several sine signals is as follows:

[0067] ① Starting from the lowest frequency of the signal, gradually increase the signal frequency according to the frequency step value until reaching the sum of the signal frequency range and the lowest frequency of the signal;

[0068] ② Starting from the minimum amplitude of the signal, gradually increase the signal amplitude according to the amplitude step value until reaching the sum of the signal amplitude range and the minimum amplitude of the signal;

[0069] ③ After each frequency and amplitude step adjustment, generate the corresponding sine signal based on the current frequency and current amplitude.

[0070] Output by the sine signal generator in the IO precision verification module The sine signal, which starts from the lowest frequency of the signal and the minimum amplitude of the signal, and steps according to the frequency step value and the amplitude step value. That is to say, for each combination of frequency and amplitude, a specific sine signal will be generated, and these signals together constitute the signal set for IO precision verification. Through such a systematic and precise sine signal generation method, the preset signal frequency range and signal amplitude range can be comprehensively covered, providing a scientific and reliable signal basis for accurately measuring the measured amplitudes and measured frequencies subsequently, and then calculating the amplitude error and frequency error, and effectively guaranteeing the comprehensiveness and accuracy of the IO interface precision detection.

[0071] Among them, for any sine signal generated by stepping, the formulas for calculating the amplitude error and the frequency error are:

[0072]

[0073]

[0074] Among them, is the amplitude error, is the current amplitude, is the measured amplitude, is the frequency error, is the current frequency, is the measured frequency.

[0075] The amplitude error reflects the deviation between the actual output amplitude and the expected set amplitude. If the amplitude error value is small and approaches zero, it indicates that the actual output amplitude highly coincides with the set amplitude, and the signal is relatively accurate in amplitude transmission; conversely, if the amplitude error value is large, it indicates that there is a deviation in amplitude transmission, which may affect the accuracy of the simulation test and further investigation and correction are required.

[0076] The frequency error reflects the difference between the actual output frequency and the theoretical set frequency. When the frequency error is close to zero, it means that the actual frequency coincides with the set frequency and the signal frequency transmission is stable; if the frequency error deviates significantly from zero, it indicates that there are problems such as frequency drift in frequency transmission, which will interfere with the entire simulation test and measures need to be taken for adjustment and optimization. The amplitude error and frequency error calculated by these two formulas can provide a key basis for subsequent calibration and optimization of the system, ensuring the reliability and accuracy of the new energy grid-connected hardware-in-the-loop simulation test.

[0077] Step S2: If there is an amplitude error or a frequency error exceeding the allowable threshold, calculate a correction coefficient based on the respective amplitude errors and the respective frequency errors, and correct the simulation model through the IO configuration module.

[0078] Specifically, when any one of the amplitude errors or frequency errors obtained through calculation exceeds the pre-set allowable threshold, it indicates that the signal transmission accuracy of the current IO interface can no longer meet the test requirements and the system needs to be corrected.

[0079] At this time, it is necessary to calculate the correction coefficient based on the respective amplitude errors and the respective frequency errors calculated in step S1. The calculation of the correction coefficient is based on the comprehensive analysis and mathematical processing of these error data, and its purpose is to be able to compensate for the deviations that occur in the signal transmission process. For example, if the amplitude error is large, the calculated correction coefficient will focus on compensating for the amplitude deviation; if the frequency error is prominent, the correction coefficient will focus on adjusting the frequency deviation.

[0080] After calculating the correction coefficient, transfer it to the IO configuration module. After receiving the correction coefficient, the IO configuration module will correct the simulation model according to this coefficient. Specifically, it will adjust the parameters related to the signal amplitude and frequency in the simulation model according to the correction coefficient.

[0081] Calculating the correction coefficient based on the respective amplitude errors and the respective frequency errors includes:

[0082] ① Determine the average amplitude error and the average frequency error based on the respective amplitude errors and the respective frequency errors;

[0083] ②Calculate a correction coefficient based on the average amplitude error and the average frequency error;

[0084] The calculation formula for the correction coefficient is:

[0085]

[0086]

[0087] where and are the correction coefficients for adjusting the signal amplitude and frequency respectively, is the average amplitude error, is the average frequency error.

[0088] Step S3: Load the preset fault type, fault phase, and fault duration parameters through the test type lookup table module, and transfer them to the desired voltage generation module.

[0089] Specifically, the test type lookup table module undertakes the important task of providing key test parameters for the desired voltage generation module. First, this module will accurately load the three core parameters of fault type, fault phase, and fault duration from the preset parameter set stored inside it. Among them, the fault type covers various different power grid fault situations such as short - circuit faults and open - circuit faults, and each fault type corresponds to a specific abnormal state of the power grid; the fault phase refers to the electrical angle position where the voltage waveform is located when the fault occurs, and it plays a crucial role in accurately simulating the power grid state at the moment of fault occurrence; the fault duration defines the duration from the occurrence to the recovery of the fault, and different fault durations will have different degrees of impact on the new - energy grid - connection system.

[0090] After successfully loading these preset parameters, the test type lookup table module will transfer them completely to the desired voltage generation module. After receiving these parameters, the desired voltage generation module can, based on this, accurately generate the target power grid voltage waveform corresponding to a specific fault type, fault phase, and fault duration. This modular parameter - loading and transfer mechanism enables the system to flexibly configure fault conditions according to different test requirements, providing a diverse and accurate power grid fault simulation environment for subsequent grid - connection simulation tests, thereby effectively evaluating the operating characteristics and response capabilities of the new - energy grid - connection system under various fault conditions.

[0091] Step S4: Generate a target power grid voltage waveform through the desired voltage generation module based on the fault type, fault phase, and fault duration parameters.

[0092] Specifically, the expected voltage generation module generates the target grid voltage waveform in the new energy grid-connected hardware-in-the-loop simulation test system based on specific parameters. Among them, the process of generating the target grid voltage waveform based on the fault type, fault phase, and fault duration parameters specifically includes:

[0093] ① Determine the output fault phase voltage waveform according to the fault type, and output the complementary phase voltage waveform through the complementary output port;

[0094] ② Determine the fault starting moment based on the fault phase and the zero phase point of the detected phase-A grid voltage;

[0095] ③ Generate a voltage amplitude step signal with a corresponding voltage drop depth according to the fault type, the fault starting moment, and the fault duration;

[0096] ④ Multiply the voltage amplitude step signal by the fault phase voltage waveform to generate a corrected fault phase voltage waveform, and then combine it with the complementary phase voltage waveform to form the target grid voltage waveform.

[0097] First, determine the output fault phase voltage waveform according to the fault type. In the case of a single-phase fault, output the voltage waveform of the corresponding phase, and at the same time generate and output the complementary voltage waveform of the non-fault phase through the complementary algorithm to ensure that the sum of the three-phase voltages is zero; in the case of a two-phase or three-phase fault, also output the fault phase voltage and the complementary complementary phase voltage waveform according to the corresponding rules. For example, in the case of a single-phase ground fault, the voltage of the fault phase will drop in amplitude, while the voltage of the non-fault phase is maintained by calculation to ensure system symmetry.

[0098] Next, use the detected zero phase point of the phase-A grid voltage as the time reference, and combine the fault phase parameter to determine the fault starting moment. Specifically, convert the fault phase into a time delay amount, and trigger the fault after this delay time after the phase-A voltage passes through the zero point to achieve precise control of the fault occurrence moment. For example, if the fault phase is 30°, trigger the fault after a 1.67 ms delay (corresponding to a 50 Hz power frequency) after the phase-A voltage passes through the zero point.

[0099] Then, generate a corresponding voltage amplitude step signal according to the fault type and the fault duration. Different fault types correspond to different voltage drop depths. For example, a single-phase ground fault usually causes the voltage of the fault phase to drop to 0.2 - 0.3 pu. This step signal is triggered at the fault starting moment and maintains the corresponding amplitude during the fault duration, and returns to the normal level after the fault ends.

[0100] Finally, multiply the generated voltage amplitude step signal by the fault phase voltage waveform to obtain the corrected fault phase voltage waveform, which accurately reflects the change in voltage amplitude during the fault. Then, combine the corrected fault phase voltage waveform with the supplementary phase voltage waveform to form a complete three-phase target grid voltage waveform. This waveform can precisely simulate the grid voltage characteristics under specific fault types, fault phases, and fault durations, providing a reliable voltage signal input for subsequent grid connection simulation tests to evaluate the response performance and grid connection characteristics of new energy equipment under fault conditions.

[0101] Step S5: Adjust the port voltage of the simulation model to the target grid voltage waveform through the IO configuration module, and interact with the new energy controller through the IO interface to complete the grid connection simulation test.

[0102] Specifically, the IO configuration module, as a key hub connecting the simulation model and the new energy controller, undertakes the important task of converting the theoretical waveform into an actual test signal. Specifically, after the desired voltage generation module outputs the target grid voltage waveform, the IO configuration module first comprehensively analyzes and adjusts the voltage parameters inside the simulation model. It will reconfigure the parameters of each node responsible for voltage output in the simulation model according to the key parameters such as the frequency, amplitude, and phase of the target grid voltage waveform. Through algorithm calculation and signal processing, the original port voltage of the simulation model is gradually adjusted to a state that completely matches the target grid voltage waveform.

[0103] When the port voltage of the simulation model is adjusted, the IO configuration module establishes a data interaction channel with the new energy controller through the IO interface. On the one hand, the IO interface transmits the adjusted target grid voltage waveform signal to the new energy controller in a format that conforms to the communication protocol, simulating the voltage input in a real grid environment, so that the new energy controller executes the control strategy based on this signal. On the other hand, the IO interface real-time receives data such as control signals and operating states feedback by the new energy controller and transmits them back to the simulation model, forming a closed-loop data interaction process. During the entire interaction process, the IO configuration module continuously monitors the accuracy and stability of signal transmission, and compensates and corrects problems such as signal attenuation and delay in real-time, ensuring smooth and error-free data interaction between the new energy controller and the simulation model, and finally completing the entire new energy grid connection hardware-in-the-loop simulation test, providing reliable test data and analysis basis for evaluating the grid connection performance of new energy equipment.

[0104] As can be seen from the above technical solutions, a new energy grid-connected hardware-in-the-loop simulation test method and system provided by an embodiment of the present application effectively avoid the defects of the prior art through the coordinated operation of multiple modules. The present application uses an IO accuracy verification module to step-generate sine signals based on preset signal parameters, calculates the measured amplitude and frequency errors compared with the preset values, and corrects the simulation model using the IO configuration module when the error exceeds the limit. This process accurately solves the problems in the prior art where inaccurate signal transmission and large differences in test results are caused by IO drift. At the same time, with the help of the test type lookup table module and the expected voltage generation module, it is possible to automatically generate the target grid voltage waveform according to the preset fault type, fault phase, and fault duration parameters, and complete the test by adjusting the port voltage of the simulation model to interact with the new energy controller through the IO configuration module, thereby achieving precise control of the fault triggering moment and avoiding the problem of unreliable test results caused by the randomness of fault triggering. The present application realizes the automatic verification of IO accuracy and the automatic generation of fault voltage waveforms, greatly improving the accuracy and consistency of test results, significantly enhancing the efficiency of new energy grid-connected hardware-in-the-loop simulation tests and comparisons, and effectively overcoming the deficiencies of the prior art.

[0105] A new energy grid-connected hardware-in-the-loop simulation test device provided by an embodiment of the present application will be described below. The new energy grid-connected hardware-in-the-loop simulation test device described below can be mutually referred to with the new energy grid-connected hardware-in-the-loop simulation test method described above.

[0106] As Figure 1 shown, the new energy grid-connected hardware-in-the-loop simulation test system includes a test type lookup table module 101, an expected voltage generation module 102, an IO accuracy verification module 103, an IO configuration module 104, and an IO interface 105;

[0107] The test type lookup table module is used to store and load preset fault type, fault phase, and fault duration parameters;

[0108] The expected voltage generation module is used to generate a target grid voltage waveform based on the fault type, fault phase, and fault duration parameters;

[0109] The IO accuracy verification module is used to step-generate and output a plurality of sine signals that meet the signal frequency range and signal amplitude range according to the preset minimum signal frequency, frequency step value, minimum signal amplitude, and amplitude step value, measure the measured amplitude and measured frequency of the IO interface, and calculate each amplitude error and each frequency error;

[0110] The IO configuration module is used to compensate the signal amplitude and frequency of the simulation model based on the correction coefficient, and adjust the port voltage of the simulation model to the target grid voltage waveform;

[0111] The IO interface is connected to the new energy controller as an interaction interface to complete the grid connection simulation test.

[0112] Specifically, the test type lookup table module 101 is the parameter center of the entire system, which pre-stores key parameters such as various fault types, fault phases, and fault durations. When the test starts, this module can accurately load these preset parameters to provide a clear basis for fault simulation in the subsequent test process.

[0113] After receiving the parameters from the test type lookup table module 101, the desired voltage generation module 102 generates a target grid voltage waveform that meets the requirements according to the fault type, fault phase, and fault duration through a specific algorithm. This waveform highly restores the voltage change of the actual grid under the fault state and provides a real voltage signal input for the simulation test.

[0114] The IO accuracy verification module 103 is mainly responsible for ensuring the accuracy of system signal transmission. It gradually generates a series of sine signals covering a specific frequency and amplitude range according to the preset minimum signal frequency, frequency step value, minimum signal amplitude, and amplitude step value. After these signals are output through the IO interface 105, the module measures the measured amplitude and measured frequency of the signals and calculates the amplitude error and frequency error of each signal, so as to judge whether the transmission accuracy of the IO interface meets the standard.

[0115] The IO configuration module 104 is used to receive the correction coefficient when the IO accuracy verification module finds that the error exceeds the limit, compensate the signal amplitude and frequency of the simulation model, and correct the deviation caused by factors such as IO drift; after obtaining the target grid voltage waveform output by the desired voltage generation module, the IO configuration module accurately adjusts the port voltage of the simulation model to this waveform to ensure that the simulation signal is consistent with the actual fault scenario.

[0116] As the only channel for the system to interact with the new energy controller, the IO interface 105 is responsible for transmitting the signals generated by the simulation model to the new energy controller, and at the same time receiving the control instructions and operation data fed back by the controller. With stable and reliable communication capabilities, it realizes the data interaction between the two, ensures that the entire new energy grid connection simulation test can be successfully completed, and then provides accurate data support for evaluating the grid connection performance of new energy equipment.

[0117] As can be seen from the above technical solution, a new energy grid-connected hardware-in-the-loop simulation test method and system provided by the embodiments of the present application effectively avoid the defects of the prior art through the collaborative operation of multiple modules. The present application utilizes an IO accuracy verification module to stepwise generate a sine signal based on preset signal parameters, calculates the measured amplitude and frequency errors compared with the preset values, and corrects the simulation model using the IO configuration module when the error exceeds the limit. This process precisely solves the problems in the prior art where inaccurate signal transmission and large differences in test results are caused by IO drift. At the same time, with the help of the test type lookup table module and the desired voltage generation module, it is possible to automatically generate the target grid voltage waveform according to the preset fault type, fault phase, and fault duration parameters, and complete the test by adjusting the port voltage of the simulation model and interacting with the new energy controller through the IO configuration module, thereby achieving precise control of the fault triggering moment and avoiding the problem of unreliable test results caused by the randomness of fault triggering. The present application realizes the automatic verification of IO accuracy and the automatic generation of fault voltage waveforms, greatly improving the accuracy and consistency of test results, significantly enhancing the efficiency of new energy grid-connected hardware-in-the-loop simulation tests and comparisons, and effectively overcoming the deficiencies of the prior art.

[0118] Among them, as Figure 3 shown, the desired voltage generation module may include:

[0119] A fault phase selection sub-module 1021 that selects and outputs a fault phase voltage waveform according to the fault type and outputs a complementary phase voltage waveform through a complementary output port;

[0120] A zero-crossing detection sub-module 1022 that is used to detect the zero-phase point of the A-phase grid voltage and determine the fault start time according to the fault phase and the zero-phase point;

[0121] A low-high voltage crossing sub-module 1023 that is used to generate a voltage amplitude step signal with a corresponding drop depth according to the fault type, the fault start time, and the fault duration;

[0122] A signal combination sub-module 1024 that multiplies the voltage amplitude step signal by the fault phase voltage waveform to generate a fault phase corrected voltage waveform, and then combines it with the complementary phase voltage waveform to form a target grid voltage waveform.

[0123] Specifically, in the new energy grid-connected hardware-in-the-loop simulation test system, the desired voltage generation module consists of multiple sub-modules working collaboratively to generate the target grid voltage waveform.

[0124] The fault phase selection sub-module 1021, as the core unit of waveform selection, intelligently identifies and outputs the corresponding fault phase voltage waveform according to the preset fault type parameters. For example, in the case of a single-phase ground fault, this sub-module will accurately select the voltage waveform of the fault phase (such as phase A) for output. At the same time, through the complementary output mechanism, it automatically generates and outputs the supplementary voltage waveforms of the non-fault phases (phase B and phase C) to ensure the symmetry and balance of the three-phase voltages. This complementary output design enables the system to accurately simulate the actual changes in the grid voltage under different fault types.

[0125] For example, according to the FltType in the test type lookup table module, select the voltage waveform of the corresponding phase. That is, when FltType is a single-phase fault, the Out port of the fault phase selection sub-module selects and outputs the voltage Va; when FltType is a two-phase fault, the Out port of the fault phase selection sub-module selects and outputs the voltages Va and Vb; when FltType is a three-phase fault, the Out port of the fault phase selection sub-module selects and outputs the voltages Va, Vb, and Vc; when FltType is a non-fault, the Out port of the fault phase selection sub-module selects and outputs 0. The ports of the fault phase selection sub-module are complementary to the Out port. That is, when the Out port selects and outputs the voltage Va, the ports output Vb and Vc; when the Out port selects and outputs the voltages Va and Vb, the ports output Vc; when the Out port selects and outputs the voltages Va, Vb, and Vc, the ports output 0.

[0126] The zero-crossing detection sub-module 1022 continuously monitors the input grid voltage of phase A. With its high-precision detection ability, it can accurately capture the zero-phase point of the grid voltage of phase A. This zero-phase point is the key to the entire time reference. Then, this module performs accurate time calculation according to the preset fault trigger phase θ parameter in the test type lookup table module. Since an electrical angle cycle corresponds to a specific time length, by converting the θ angle into the corresponding time quantity, a time delay is performed based on the zero-phase point of the grid voltage of phase A. When the time delay reaches the time corresponding to the θ angle, the module triggers and generates a fault start time signal, which accurately determines the starting time of the fault in the grid voltage cycle and provides an accurate time reference for subsequent fault simulation.

[0127] The high-low voltage sub-module 1023 determines the fault type based on the FltType signal in the test type lookup table module. Different fault types, such as short circuit and open circuit, will cause different degrees of voltage dips or rises in the power grid voltage, that is, they have different dip depths. According to information such as the fault type, the fault start time determined by the zero-crossing detection sub-module, and the fault duration, a voltage amplitude step signal corresponding to the dip depth is generated. Different fault types correspond to different voltage dip depths. This sub-module can accurately simulate this characteristic, trigger the step signal at the fault start time, and maintain the corresponding amplitude change during the fault duration.

[0128] The signal combination sub-module 1024 multiplies the voltage amplitude step signal generated by the high-low voltage sub-module by the fault phase voltage waveform output by the fault phase selection sub-module to obtain the fault phase corrected voltage waveform. This operation enables the voltage amplitude step signal to be triggered at the accurate fault start time, so as to obtain the fault phase power grid voltage waveform that meets the requirements. This waveform not only contains the information at the fault occurrence time but also reflects the change in voltage amplitude during the fault. Then, the signal combination sub-module combines the fault phase corrected voltage waveform with the supplementary phase voltage waveform to finally form the complete target power grid voltage waveform Vgrid. This waveform highly simulates the power grid voltage state under specific fault conditions, provides accurate voltage signal input for new energy grid connection simulation tests, and helps to accurately evaluate the operating performance of new energy equipment under fault conditions.

[0129] Furthermore, the complementary output port of the fault phase selection sub-module outputs three-phase voltage waveforms when there is no fault, outputs the corresponding non-fault phase voltage waveforms when there is a single-phase or two-phase fault, and outputs a zero signal when there is a three-phase fault.

[0130] Specifically, the complementary output port of the fault phase selection sub-module has the ability of intelligent switching and can automatically adjust the output content according to the fault type. In the non-fault state, this port outputs complete three-phase voltage waveforms to ensure that the simulation system simulates the normal power grid operating environment. When a single-phase or two-phase fault occurs, the complementary output port accurately outputs the corresponding non-fault phase voltage waveforms. For example, when there is a single-phase fault in phase A, the voltage waveforms of phases B and C are output to maintain the symmetry of the three-phase system. In the case of a three-phase fault, the complementary output port outputs a zero signal to simulate the extreme condition of complete power grid voltage loss, providing comprehensive fault simulation capabilities for the system.

[0131] Furthermore, the voltage amplitude step signal generated by the high-low voltage sub-module is synchronized with the fault start time output by the zero-crossing detection sub-module, so that the voltage amplitude dip depth matches the fault type and the fault duration.

[0132] Specifically, the voltage amplitude step signal generated by the high-low voltage sub-module is strictly synchronized with the fault starting moment output by the zero-crossing detection sub-module, ensuring that the voltage amplitude drop depth is precisely matched with the fault type and fault duration. This sub-module triggers an instantaneous step change in the voltage amplitude at the fault starting moment according to the preset drop depth parameters for different fault types (such as single-phase grounding, two-phase short circuit, etc.), and maintains the set drop level throughout the fault duration. For example, in a single-phase grounding fault, the voltage amplitude of the fault phase will rapidly drop to 0.2 - 0.3 pu and continue until the fault is cleared, achieving a high degree of restoration of the fault characteristics of the real power grid.

[0133] Further, the target power grid voltage waveform generated by the desired voltage generation module drives the simulation model in the IO configuration module, making the port voltage of the simulation model consistent with the target power grid voltage waveform.

[0134] Specifically, the target power grid voltage waveform finally generated by the desired voltage generation module acts as a driving signal on the simulation model in the IO configuration module. Specifically, this waveform controls the three-phase controlled voltage source in the simulation model, making the port voltage of the voltage source strictly consistent with the target power grid voltage waveform throughout the test process. This precise voltage control ability enables the simulation model to accurately simulate the electrical characteristics of the real power grid under different fault conditions, providing a realistic test environment for the new energy controller. In this way, the system can automatically generate a fault power grid voltage that meets the conditions according to the fault type, fault phase angle, and fault duration preset by the user, significantly improving the efficiency and accuracy of the new energy grid-connected hardware-in-the-loop simulation test.

[0135] Finally, it should also be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0136] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other.

[0137] The foregoing description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for hardware-in-the-loop simulation test of new energy grid connection, characterized in that, Applied to a new energy grid-connected hardware-in-the-loop simulation test system including a test type lookup table module, an expected voltage generation module, an IO accuracy verification module, an IO configuration module, and an IO interface, the method includes: Based on a preset signal minimum frequency, frequency step value, signal minimum amplitude, and amplitude step value, the IO accuracy verification module stepwise generates a plurality of sine signals that conform to the signal frequency range and signal amplitude range, outputs them through the IO interface, measures the corresponding measured amplitudes and measured frequencies, and calculates each amplitude error and each frequency error; If there is an amplitude error or a frequency error that exceeds the allowable threshold, calculate a correction coefficient according to each amplitude error and each frequency error, and correct the simulation model through the IO configuration module; Load preset fault type, fault phase, and fault duration parameters through the test type lookup table module and transfer them to the expected voltage generation module; Generate a target grid voltage waveform based on the fault type, fault phase, and fault duration parameters through the expected voltage generation module; Adjust the port voltage of the simulation model to the target grid voltage waveform through the IO configuration module, and interact with the new energy controller through the IO interface to complete the grid connection simulation test.

2. The method according to claim 1, wherein The generation method of the plurality of sine signals is as follows: Taking the signal minimum frequency as the starting frequency, gradually increase the signal frequency according to the frequency step value until reaching the sum of the signal frequency range and the signal minimum frequency; Taking the signal minimum amplitude as the starting amplitude, gradually increase the signal amplitude according to the amplitude step value until reaching the sum of the signal amplitude range and the signal minimum amplitude; After each frequency and amplitude step adjustment, generate a corresponding sine signal based on the current frequency and current amplitude.

3. The method according to claim 2, wherein For any sine signal generated stepwise, the formulas for calculating the amplitude error and the frequency error are: Among them, is the amplitude error, is the current amplitude, is the measured amplitude, is the frequency error, is the current frequency, is the measured frequency.

4. The method according to claim 1, wherein Calculating the correction coefficient according to each amplitude error and each frequency error includes: Determine the average amplitude error and the average frequency error according to each amplitude error and each frequency error; Based on the average amplitude error and the average frequency error, calculate the correction coefficient; The calculation formula of the correction coefficient is: Wherein, and are correction coefficients for adjusting the signal amplitude and frequency respectively, is the average amplitude error, is the average frequency error.

5. The method according to claim 1, wherein Generating a target grid voltage waveform based on the fault type, fault phase, and fault duration parameters includes: Determine the output fault phase voltage waveform according to the fault type, and output the complementary phase voltage waveform through the complementary output port; Determine the fault start time based on the fault phase and the zero phase point of the detected phase A grid voltage; Generate a voltage amplitude step signal with a corresponding drop depth according to the fault type, the fault start time, and the fault duration; Multiply the voltage amplitude step signal by the fault phase voltage waveform to generate a fault phase corrected voltage waveform, and then combine it with the complementary phase voltage waveform to form a target grid voltage waveform.

6. A new energy grid-connected hardware-in-the-loop simulation test system, characterized in that, Including a test type lookup table module, an expected voltage generation module, an IO accuracy verification module, an IO configuration module, and an IO interface; The test type lookup table module is used to store and load preset fault type, fault phase, and fault duration parameters; An expected voltage generation module, configured to generate a target grid voltage waveform based on the fault type, fault phase, and fault duration parameters; An IO accuracy verification module, configured to stepwise generate and output a plurality of sine signals that meet the signal frequency range and signal amplitude range according to a preset minimum signal frequency, frequency step value, minimum signal amplitude, and amplitude step value, measure the measured amplitude and measured frequency of the IO interface, and calculate each amplitude error and each frequency error; An IO configuration module, configured to compensate the signal amplitude and frequency of the simulation model based on the correction coefficient, and adjust the port voltage of the simulation model to the target grid voltage waveform; An IO interface, serving as an interactive interface to connect with a new energy controller to complete a grid connection simulation test.

7. The system according to claim 6, wherein The expected voltage generation module includes: A fault phase selection sub-module, configured to select and output a fault phase voltage waveform according to the fault type, and output a complementary phase voltage waveform through a complementary output port; A zero-crossing detection sub-module, configured to detect the zero-phase point of the A-phase grid voltage, and determine the fault start time according to the fault phase and the zero-phase point; A low-high voltage crossing sub-module, configured to generate a voltage amplitude step signal with a corresponding drop depth according to the fault type, the fault start time, and the fault duration; A signal combination sub-module, configured to multiply the voltage amplitude step signal by the fault phase voltage waveform to generate a fault phase corrected voltage waveform, and then combine it with the complementary phase voltage waveform to form a target grid voltage waveform.

8. The system according to claim 6, wherein The complementary output port of the fault phase selection sub-module outputs three-phase voltage waveforms when there is no fault, outputs the corresponding non-fault phase voltage waveforms in case of single-phase or two-phase faults, and outputs a zero signal in case of three-phase faults.

9. The system according to claim 6, wherein The voltage amplitude step signal generated by the low-high voltage crossing sub-module is synchronized with the fault start time output by the zero-crossing detection sub-module, so that the voltage amplitude drop depth matches the fault type and the fault duration.

10. The system according to claim 6, wherein The target grid voltage waveform generated by the expected voltage generation module drives the simulation model in the IO configuration module, so that the port voltage of the simulation model is consistent with the target grid voltage waveform.

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