A frequency response analysis method for photovoltaic grid-connected systems

Abstract

The present invention relates to the technical field of establishing analysis models, and discloses a frequency response analysis method for a photovoltaic grid-connected system, the method comprising: collecting component data and operating parameters of the photovoltaic grid-connected system to analyze the power performance of the photovoltaic grid-connected system; identifying the topological structure of the inverter in the photovoltaic grid-connected system to analyze the transmission damping of the inverter, and analyzing the transmission efficiency of the inverter according to the transmission damping; constructing a photovoltaic grid-connected model of the photovoltaic grid-connected system, analyzing the frequency domain response characteristics of the photovoltaic grid-connected system, determining the spectrum diagram and frequency components of the photovoltaic grid-connected system based on the frequency domain response characteristics, and then analyzing the equivalent inertia of the photovoltaic grid-connected system; performing frequency response analysis on the photovoltaic grid-connected system according to the power performance, transmission efficiency, and equivalent inertia, obtaining analysis results, and creating a response analysis model according to the analysis results to analyze the frequency response of the photovoltaic grid-connected system in real time. The present invention can improve the accuracy of the frequency response analysis of the photovoltaic grid-connected system.

Description

Technical Field

[0001] The present invention relates to the technical field of analytical model establishment, and in particular to a frequency response analysis method for a photovoltaic grid-connected system. Background Art

[0002] Photovoltaic grid-connected system refers to the connection of photovoltaic power generation system (system composed of solar photovoltaic cells) with the public power grid to realize the transmission of electricity generated by photovoltaic power generation system to the power grid. This system usually consists of photovoltaic array, inverter, grid connection equipment and monitoring system. The working principle of photovoltaic grid-connected system is to convert the direct current generated by photovoltaic modules into alternating current and inject it into the power grid synchronously through inverter. During the day, when the sun shines on the photovoltaic modules, the system generates electricity, part of which is used to supply local loads, and the excess is transmitted to the power grid. At night or when there is insufficient light, the system obtains the required electricity from the power grid. The advantages of photovoltaic grid-connected system include the utilization of renewable energy, reducing dependence on fossil energy, and reducing carbon emissions. However, it should be noted that the system design should consider factors such as stability, power regulation, and grid protection to ensure that the system operates safely and reliably and complies with local power regulations and standards.

[0003] At present, the frequency response analysis of photovoltaic grid-connected systems is generally based on mathematical models. By using mathematical models in the field of control theory and power systems, photovoltaic grid-connected systems are modeled and analyzed, and the frequency response characteristics of the system are derived. However, this method usually requires simplification and assumptions of the system in order to obtain a resolvable mathematical expression. This may lead to differences with the actual system behavior and affect the accuracy of the analysis results. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a frequency response analysis method for a photovoltaic grid-connected system. The present invention can improve the accuracy of the frequency response analysis of the photovoltaic grid-connected system.

[0005] In a first aspect, the present invention provides a frequency response analysis method for a photovoltaic grid-connected system, comprising:

[0006] Collecting component data and operating parameters of a photovoltaic grid-connected system, constructing a photovoltaic array network of the photovoltaic grid-connected system based on the component data, and analyzing power supply performance of the photovoltaic grid-connected system based on the photovoltaic array network and the operating parameters;

[0007] Identifying a topological structure of an inverter in the photovoltaic grid-connected system, analyzing a transmission damping of the inverter according to the topological structure, and analyzing a transmission efficiency of the inverter according to the transmission damping;

[0008] Constructing a photovoltaic grid-connected model of the photovoltaic grid-connected system, analyzing the frequency domain response characteristics of the photovoltaic grid-connected system using the photovoltaic grid-connected model, determining a frequency spectrum and frequency components of the photovoltaic grid-connected system based on the frequency domain response characteristics, and analyzing the equivalent inertia of the photovoltaic grid-connected system based on the frequency spectrum and the frequency components;

[0009] A frequency response analysis is performed on the photovoltaic grid-connected system according to the power supply performance, the transmission efficiency and the equivalent inertia to obtain a frequency response analysis result; a frequency response analysis model of the photovoltaic grid-connected system is created according to the analysis result; real-time data of the photovoltaic grid-connected system is collected; and based on the real-time data, a real-time frequency response analysis is performed on the photovoltaic grid-connected system using the frequency response analysis model.

[0010] In a possible implementation of the first aspect, constructing a photovoltaic array network of the photovoltaic grid-connected system based on the component data includes:

[0011] Determining circuit parameters of the photovoltaic grid-connected system based on the component data;

[0012] Constructing an initial layout of the photovoltaic grid-connected system;

[0013] arranging a preconfigured photovoltaic model using the initial layout to obtain a target model;

[0014] After the circuit parameters are input into the target model, the target model is activated to obtain a photovoltaic array network.

[0015] In a possible implementation of the first aspect, analyzing the power supply performance of the photovoltaic grid-connected system based on the photovoltaic array network and the operating parameters includes:

[0016] Analyzing output characteristics of the photovoltaic grid-connected system using the photovoltaic array network and the operating parameters;

[0017] Based on the output characteristics, constructing a time-output current curve diagram of the photovoltaic grid-connected system;

[0018] Based on the time-output current curve, analyzing the current output fluctuation of the photovoltaic grid-connected system;

[0019] The power supply performance of the photovoltaic grid-connected system is analyzed based on the current output fluctuation.

[0020] In a possible implementation manner of the first aspect, analyzing the transmission damping of the inverter according to the topology structure includes:

[0021] Determining a connection mode of resistors in the inverter based on the topological structure;

[0022] Calculating the resistance, inductance and capacitance of the resistor based on the connection method;

[0023] The damping ratio of the inverter is calculated based on the resistance, the inductance and the capacitance using the following formula:

[0024]

[0025] in, represents the damping ratio, Represents resistance, represents inductance, Represents capacitance;

[0026] The frequency range of the inverter is identified, and the transmission damping of the inverter is calculated based on the frequency range and the damping ratio using the following formula:

[0027]

[0028] in, represents the transmission damping, represents the damping ratio, Indicates the frequency range of the inverter.

[0029] In a possible implementation manner of the first aspect, calculating the resistance, inductance, and capacitance of the resistor based on the connection manner includes:

[0030] When the connection mode is parallel connection, the resistance, inductance and capacitance of the resistor are calculated using the following formula;

[0031]

[0032]

[0033]

[0034] in, Represents resistance, represents inductance, Capacitance indicates, represents the resistance of the first inductor in the resistor chain, represents the resistance of the second inductor in the resistor, represents the resistance of the nth inductor in the resistor chain, represents the inductance of the first inductor in the resistor, represents the inductance of the second inductor in the resistor, represents the inductance of the nth inductor in the resistor, represents the capacitance of the first inductor in the resistor, represents the capacitance of the second inductor in the resistor, represents the capacitance of the nth inductor in the resistor;

[0035] When the connection mode is series connection, the resistance, inductance and capacitance of the resistor are calculated using the following formula:

[0036]

[0037]

[0038]

[0039] in, Represents resistance, represents inductance, Capacitance indicates, represents the resistance of the first inductor in the resistor chain, represents the resistance of the second inductor in the resistor, represents the resistance of the nth inductor in the resistor chain, represents the inductance of the first inductor in the resistor, represents the inductance of the second inductor in the resistor, represents the inductance of the nth inductor in the resistor, represents the capacitance of the first inductor in the resistor, represents the capacitance of the second inductor in the resistor, Represents the capacitance of the nth inductor in the resistor.

[0040] In a possible implementation manner of the first aspect, analyzing the transmission efficiency of the inverter according to the transmission damping includes:

[0041] Performing interval matching between the calculated value of the transmission damping and the pre-built damping threshold;

[0042] Determining the system oscillation characteristics of the inverter based on the matching result of the interval matching

[0043] The transmission efficiency of the inverter is analyzed based on the system oscillation characteristics.

[0044] In a possible implementation of the first aspect, analyzing the frequency domain response characteristics of the photovoltaic grid-connected system by using the photovoltaic grid-connected model includes:

[0045] Extracting input signals and output signals in the photovoltaic grid-connected model;

[0046] Performing frequency domain conversion on the input signal and the output signal to obtain a converted input signal and a converted output signal;

[0047] Performing frequency domain analysis on the conversion input signal and the conversion output signal to obtain a frequency domain analysis result;

[0048] Based on the analysis results, the frequency domain response characteristics of the photovoltaic grid-connected system are analyzed.

[0049] In a possible implementation manner of the first aspect, analyzing the equivalent inertia of the photovoltaic grid-connected system based on the frequency spectrum and the frequency components includes:

[0050] After a disturbance signal is input to the photovoltaic grid-connected system, recording disturbance data of the photovoltaic grid-connected system;

[0051] Constructing a response impact model of the photovoltaic grid-connected system according to the disturbance data, the frequency spectrum and the frequency components;

[0052] The response impact model is used to analyze the equivalent inertia of the photovoltaic grid-connected system.

[0053] In a possible implementation manner of the first aspect, performing frequency response analysis on the photovoltaic grid-connected system according to the power supply performance, the transmission efficiency, and the equivalent inertia to obtain a frequency response analysis result includes:

[0054] Performing data conversion on the power supply performance, the transmission efficiency and the equivalent inertia to obtain conversion data;

[0055] Calculating a covariance matrix of the transformed data, and performing eigenvalue decomposition on the covariance matrix to obtain decomposition eigenvalues;

[0056] Performing data screening on the converted data based on the decomposed characteristic values ​​to obtain screened data;

[0057] Mapping the screened data into a low-dimensional space to obtain low-dimensional mapping data;

[0058] Visual analysis is performed on the low-dimensional mapping data to obtain a frequency response analysis result.

[0059] In a second aspect, the present invention provides a frequency response analysis system for a photovoltaic grid-connected system, the system comprising:

[0060] A performance analysis module, used to collect component data and operating parameters of the photovoltaic grid-connected system, construct a photovoltaic array network of the photovoltaic grid-connected system based on the component data, and analyze the power supply performance of the photovoltaic grid-connected system based on the photovoltaic array network and the operating parameters;

[0061] A transmission efficiency analysis module, used to identify the topology of the inverter in the photovoltaic grid-connected system, analyze the transmission damping of the inverter according to the topology, and analyze the transmission efficiency of the inverter according to the transmission damping;

[0062] an equivalent inertia analysis module, used to construct a photovoltaic grid-connected model of the photovoltaic grid-connected system, analyze the frequency domain response characteristics of the photovoltaic grid-connected system using the photovoltaic grid-connected model, determine the frequency spectrum and frequency components of the photovoltaic grid-connected system based on the frequency domain response characteristics, and analyze the equivalent inertia of the photovoltaic grid-connected system based on the frequency spectrum and the frequency components;

[0063] An analysis model creation module is used to perform frequency response analysis on the photovoltaic grid-connected system according to the power supply performance, the transmission efficiency and the equivalent inertia to obtain a frequency response analysis result, create a frequency response analysis model of the photovoltaic grid-connected system according to the analysis result, collect real-time data of the photovoltaic grid-connected system, and perform real-time frequency response analysis on the photovoltaic grid-connected system using the frequency response analysis model based on the real-time data.

[0064] Compared with the prior art, the technical principle and beneficial effects of this solution are:

[0065] The embodiment of the present invention can establish a remote monitoring and management system by collecting component data and operating parameters of the photovoltaic grid-connected system, realize real-time monitoring, remote operation and intelligent management of the photovoltaic grid-connected system, improve the operating efficiency and reliability of the system, and analyze the power supply performance of the photovoltaic grid-connected system based on the photovoltaic array network and the operating parameters to help users understand the power output of the system under different conditions, so as to make adjustments and optimizations to improve system efficiency and performance. Furthermore, the embodiment of the present invention can understand the structural composition of the inverter by identifying the topological structure of the inverter in the photovoltaic grid-connected system, and then analyze the circuit principle of the inverter, and construct a photovoltaic grid-connected model of the photovoltaic grid-connected system to conduct simulation experiments, in which the photovoltaic grid-connected model can be used to simulate the photovoltaic grid-connected system. Different operation strategies, control algorithms or hardware configurations are tested in the environment to analyze the operation of the photovoltaic grid-connected system. Furthermore, the embodiment of the present invention performs frequency response analysis on the photovoltaic grid-connected system according to the power supply performance, the transmission efficiency and the equivalent inertia. The frequency response analysis results can understand the response characteristics of the system at different frequencies, which helps users to design better control strategies and further improve the performance and reliability of the photovoltaic grid-connected system. Based on the analysis results, a frequency response analysis model of the photovoltaic grid-connected system is created. Data models can reveal potential patterns, relationships and insights in data, and help discover information that is not easily perceived. Models can help predict future trends, behaviors or results, thereby guiding decision making and planning. A frequency response analysis method and system for a photovoltaic grid-connected system proposed in an embodiment of the present invention can improve the accuracy of frequency response analysis of a photovoltaic grid-connected system. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0067] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0068] Figure 1 A schematic flow chart of a frequency response analysis method for a photovoltaic grid-connected system provided by an embodiment of the present invention;

[0069] Figure 2 A schematic diagram of a module of a frequency response analysis system for a photovoltaic grid-connected system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0070] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0071] The embodiment of the present invention provides a frequency response analysis method for a photovoltaic grid-connected system, and the execution subject of the frequency response analysis method for a photovoltaic grid-connected system includes but is not limited to at least one of the electronic devices such as a server and a terminal that can be configured to execute the method provided by the embodiment of the present invention. In other words, the frequency response analysis method for a photovoltaic grid-connected system can be executed by software or hardware installed in a terminal device or a server device, and the software can be a blockchain platform. The server includes but is not limited to: a single server, a server cluster, a cloud server or a cloud server cluster, etc. The server can be an independent server, or it can be a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, content delivery networks (Content Delivery Network, CDN), and big data and artificial intelligence platforms.

[0072] See also Figure 1 FIG. 1 is a flow chart of a frequency response analysis method for a photovoltaic grid-connected system provided by an embodiment of the present invention. Figure 1 A frequency response analysis method for a photovoltaic grid-connected system described in the specification includes:

[0073] S1. Collect component data and operating parameters of a photovoltaic grid-connected system, construct a photovoltaic array network of the photovoltaic grid-connected system based on the component data, and analyze power supply performance of the photovoltaic grid-connected system based on the photovoltaic array network and the operating parameters.

[0074] The embodiment of the present invention can establish a remote monitoring and management system by collecting the component data and operating parameters of the photovoltaic grid-connected system, realize real-time monitoring, remote operation and intelligent management of the photovoltaic grid-connected system, and improve the operating efficiency and reliability of the system. Among them, the component data refers to the components of the photovoltaic grid-connected system such as photovoltaic components, support structures, and monitoring and control equipment, and the operating parameters refer to the operating voltage, rated current and other parameters of the photovoltaic grid-connected system.

[0075] Furthermore, the embodiments of the present invention can be used to analyze the performance of photovoltaic arrays, such as power generation, power generation efficiency, and power curve, by constructing a photovoltaic array network of the photovoltaic grid-connected system based on the component data.

[0076] As an embodiment of the present invention, constructing a photovoltaic array network of the photovoltaic grid-connected system based on the component data includes: determining circuit parameters of the photovoltaic grid-connected system based on the component data, constructing an initial layout of the photovoltaic grid-connected system, using the initial layout to arrange a preconfigured photovoltaic model to obtain a target model, and after inputting the circuit parameters into the target model, activating the target model to obtain a photovoltaic array network.

[0077] Optionally, the initial layout of the photovoltaic grid-connected system is obtained by querying the installation direction and tilt angle of the photovoltaic array in the photovoltaic grid-connected system. The preconfigured photovoltaic model can be selected according to actual conditions, such as a single diode model, a two-diode model, a detailed equivalent circuit model, etc.

[0078] The embodiment of the present invention can help users understand the power output of the system under different conditions by analyzing the power supply performance of the photovoltaic grid-connected system based on the photovoltaic array network and the operating parameters, so as to make adjustments and optimizations to improve system efficiency and performance.

[0079] As an embodiment of the present invention, the analyzing the power supply performance of the photovoltaic grid-connected system based on the photovoltaic array network and the operating parameters includes: analyzing the output characteristics of the photovoltaic grid-connected system using the photovoltaic array network and the operating parameters, constructing a time-output current curve graph of the photovoltaic grid-connected system based on the output characteristics, analyzing the current output fluctuation of the photovoltaic grid-connected system based on the time-output current curve graph, and analyzing the power supply performance of the photovoltaic grid-connected system based on the current output fluctuation.

[0080] Optionally, the output characteristics of the photovoltaic grid-connected system are analyzed by utilizing the photovoltaic array network and the operating parameters to identify the number of electronic devices of the solar cells of the photovoltaic grid-connected system, the heat generated by the photovoltaic grid-connected system, and the series-parallel resistance of the batteries through the photovoltaic array network, and the output current of the solar cell, the output voltage of the solar cell and the reverse saturation current of the solar cell diode are determined through the operating parameters to identify the IU characteristics of the photovoltaic grid-connected system, and then the power supply performance of the photovoltaic grid-connected system is analyzed according to the IU characteristics.

[0081] Optionally, the time-output current curve diagram of the photovoltaic grid-connected system constructed based on the output characteristics is constructed by collecting data of multiple time periods and the output currents corresponding to the multiple time periods. Based on the time-output current curve diagram, the current output fluctuation of the photovoltaic grid-connected system is analyzed by calculating the average value of the corresponding output current in the time-output current curve diagram for difference analysis. For example, if the current output average value is 5 , the output current at the first moment is 4.99 , the output current at the second moment is 5.01 A difference range within 0.05 indicates a small fluctuation, and a difference range greater than 0.05 indicates a large fluctuation. The power supply performance of the photovoltaic grid-connected system based on the current output fluctuation analysis is analyzed by analyzing the current output fluctuation range. If the fluctuation range is small, it indicates that the power supply performance of the photovoltaic grid-connected system is stable. If the fluctuation range is large, it indicates that the power supply performance of the photovoltaic grid-connected system is not stable enough.

[0082] S2. Identify the topological structure of the inverter in the photovoltaic grid-connected system, analyze the transmission damping of the inverter according to the topological structure, and analyze the transmission efficiency of the inverter according to the transmission damping.

[0083] The embodiment of the present invention can understand the structural composition of the inverter by identifying the topological structure of the inverter in the photovoltaic grid-connected system, and then analyze the circuit principle of the inverter.

[0084] Optionally, the topological structure of the inverter can be obtained by querying the design drawings of the inverter.

[0085] Furthermore, the embodiment of the present invention can analyze the response speed and stability of the photovoltaic grid-connected system by analyzing the transmission damping of the inverter according to the topological structure. The transmission damping refers to an important parameter used in the control system to stabilize system oscillation or prevent system instability.

[0086] As an embodiment of the present invention, analyzing the transmission damping of the inverter according to the topological structure includes: determining a connection mode of a resistor in the inverter based on the topological structure, calculating the resistance, inductance and capacitance of the resistor based on the connection mode, and calculating the damping ratio of the inverter based on the resistance, the inductance and the capacitance using the following formula:

[0087]

[0088] in, represents the damping ratio, Represents resistance, represents inductance, Represents capacitance;

[0089] The frequency range of the inverter is identified, and the transmission damping of the inverter is calculated based on the frequency range and the damping ratio using the following formula:

[0090]

[0091] in, represents the transmission damping, represents the damping ratio, Indicates the frequency range of the inverter.

[0092] Further, in another optional embodiment of the present invention, the calculating the resistance, inductance and capacitance of the resistor based on the connection mode includes: when the connection mode is parallel, calculating the resistance, inductance and capacitance of the resistor using the following expression;

[0093]

[0094]

[0095]

[0096] in, Represents resistance, represents inductance, Capacitance indicates, represents the resistance of the first inductor in the resistor chain, represents the resistance of the second inductor in the resistor, represents the resistance of the nth inductor in the resistor chain, represents the inductance of the first inductor in the resistor, represents the inductance of the second inductor in the resistor, represents the inductance of the nth inductor in the resistor, represents the capacitance of the first inductor in the resistor, represents the capacitance of the second inductor in the resistor, represents the capacitance of the nth inductor in the resistor;

[0097] When the connection mode is series connection, the resistance, inductance and capacitance of the resistor are calculated using the following formula:

[0098]

[0099]

[0100]

[0101] in, Represents resistance, represents inductance, Capacitance indicates, represents the resistance of the first inductor in the resistor chain, represents the resistance of the second inductor in the resistor, represents the resistance of the nth inductor in the resistor chain, represents the inductance of the first inductor in the resistor, represents the inductance of the second inductor in the resistor, represents the inductance of the nth inductor in the resistor, represents the capacitance of the first inductor in the resistor, represents the capacitance of the second inductor in the resistor, Represents the capacitance of the nth inductor in the resistor.

[0102] The embodiment of the present invention can help determine the energy loss of the system and identify potential sources of energy loss by analyzing the transmission efficiency of the inverter according to the transmission damping, and then take corresponding measures to optimize the system design or operation strategy to improve the overall transmission efficiency of the photovoltaic system.

[0103] As an embodiment of the present invention, the analysis of the transmission efficiency of the inverter according to the transmission damping includes: performing interval matching between the calculated value of the transmission damping and a pre-built damping threshold, determining the system oscillation characteristics of the inverter based on the matching result of the interval matching, and analyzing the transmission efficiency of the inverter based on the system oscillation characteristics. The pre-built damping threshold refers to a damping threshold interval divided in advance, and the first interval is , the second interval is , the third interval is .

[0104] Optionally, the system oscillation characteristics of the inverter are determined by the matching result based on the interval matching, and when the matching result is the first interval and the third interval time, it indicates that the system oscillation is unstable, and when the matching result is the second interval, it indicates that the system oscillation is stable. The transmission efficiency of the inverter analyzed based on the system oscillation characteristics is determined by the oscillation characteristics, and the stable system oscillation indicates high transmission efficiency, and the unstable system oscillation indicates low transmission efficiency.

[0105] S3. Construct a photovoltaic grid-connected model of the photovoltaic grid-connected system, use the photovoltaic grid-connected model to analyze the frequency domain response characteristics of the photovoltaic grid-connected system, determine the frequency spectrum and frequency components of the photovoltaic grid-connected system based on the frequency domain response characteristics, and analyze the equivalent inertia of the photovoltaic grid-connected system based on the frequency spectrum and the frequency components.

[0106] The embodiment of the present invention can conduct simulation experiments by constructing the photovoltaic grid-connected model of the photovoltaic grid-connected system, and test different operation strategies, control algorithms or hardware configurations in a virtual environment to analyze the operation of the photovoltaic grid-connected system. The photovoltaic grid-connected model can be constructed by the HOMER tool.

[0107] Furthermore, the embodiment of the present invention can help users analyze the response of the photovoltaic grid-connected system at different frequencies by analyzing the frequency domain response characteristics of the photovoltaic grid-connected system using the photovoltaic grid-connected model, thereby identifying possible oscillation, resonance or stability problems of the system. The frequency domain response characteristics refer to the response of the photovoltaic system to input signals of different frequencies.

[0108] As an embodiment of the present invention, the use of the photovoltaic grid-connected model to analyze the frequency domain response characteristics of the photovoltaic grid-connected system includes: extracting input signals and output signals in the photovoltaic grid-connected model, performing frequency domain conversion on the input signals and the output signals to obtain converted input signals and converted output signals, performing frequency domain analysis on the converted input signals and the converted output signals to obtain frequency domain analysis results, and analyzing the frequency domain response characteristics of the photovoltaic grid-connected system based on the analysis results.

[0109] Optionally, the input signal and the output signal in the photovoltaic grid-connected model are obtained by collecting historical output and input information in the photovoltaic grid-connected system, the input signal and the output signal are converted into frequency domain to obtain a converted input signal and a converted output signal obtained by Fourier transform, and the converted input signal and the converted output signal are analyzed in frequency domain to obtain a frequency domain analysis result means that the main frequency components of the signals in the photovoltaic grid-connected system and their signal strengths or periodic vibrations are obtained through the frequency domain analysis, and their frequency values ​​can be calculated.

[0110] Furthermore, in the embodiment of the present invention, the spectrum diagram and frequency components of the photovoltaic grid-connected system determined based on the frequency domain response characteristics can be determined by the frequency domain analysis results, the spectrum diagram refers to the energy distribution of the signal at different frequencies, which can be represented by the signal intensity, and the frequency component refers to the periodic vibration of the signal, which can be represented by the frequency component.

[0111] The embodiment of the present invention can understand the dynamic adjustment parameters of the photovoltaic grid-connected system by analyzing the equivalent inertia of the photovoltaic grid-connected system based on the frequency spectrum and the frequency components. The equivalent inertia refers to an important parameter that affects the stability and dynamic response of the photovoltaic grid-connected system, affects the frequency response capability and voltage stability of the system, and can improve the performance of the system by adjusting the equivalent inertia, ensuring that the photovoltaic grid-connected system has good stability and reliability when connected to the power grid.

[0112] As an embodiment of the present invention, the analyzing the equivalent inertia of the photovoltaic grid-connected system based on the frequency spectrum and the frequency components includes: after inputting a disturbance signal into the photovoltaic grid-connected system, recording the disturbance data of the photovoltaic grid-connected system, constructing a response influence model of the photovoltaic grid-connected system according to the disturbance data, the frequency spectrum and the frequency components, and analyzing the equivalent inertia of the photovoltaic grid-connected system using the response influence model.

[0113] Optionally, the disturbance signal may be a pulse or step signal, the disturbance data refers to the output data of the photovoltaic grid-connected system after being disturbed, the response impact model refers to a mathematical model, and the response impact model of the photovoltaic grid-connected system constructed according to the disturbance data, the spectrum diagram and the frequency component can be obtained by performing linear relationship analysis and comparison on a pre-built transfer function. If the linear relationship is relatively smooth, it means that the equivalent inertia is excellent, and if the linear relationship is not smooth enough, it means that the equivalent inertia is average.

[0114] S4. Perform frequency response analysis on the photovoltaic grid-connected system according to the power supply performance, the transmission efficiency and the equivalent inertia to obtain frequency response analysis results, create a frequency response analysis model of the photovoltaic grid-connected system according to the analysis results, collect real-time data of the photovoltaic grid-connected system, and perform real-time frequency response analysis on the photovoltaic grid-connected system using the frequency response analysis model based on the real-time data.

[0115] The embodiment of the present invention performs frequency response analysis on the photovoltaic grid-connected system according to the power supply performance, the transmission efficiency and the equivalent inertia. The frequency response analysis result can be used to understand the response characteristics of the system at different frequencies, which helps users design better control strategies and further improve the performance and reliability of the photovoltaic grid-connected system.

[0116] As an embodiment of the present invention, the frequency response analysis of the photovoltaic grid-connected system is performed according to the power supply performance, the transmission efficiency and the equivalent inertia to obtain the frequency response analysis result, including: performing data conversion on the power supply performance, the transmission efficiency and the equivalent inertia to obtain conversion data, calculating the covariance matrix of the conversion data, and performing eigenvalue decomposition on the covariance matrix to obtain decomposition eigenvalues, performing data screening on the conversion data based on the decomposition eigenvalues ​​to obtain screened data, mapping the screened data into a low-dimensional space to obtain low-dimensional mapping data, and performing visualization analysis on the low-dimensional mapping data to obtain the frequency response analysis result.

[0117] Optionally, the data conversion of the power supply performance, the transmission efficiency and the equivalent inertia to obtain the converted data refers to performing scale space conversion on the data, which can be obtained by Z-score standardization processing method, the covariance matrix of the converted data can be calculated by NumPy tool in Python, the converted data is screened based on the decomposed eigenvalues ​​to obtain the screened data, the screened data is mapped to low-dimensional space by screening according to the numerical size of the decomposed eigenvalues, and low-dimensional mapping data is obtained by low-dimensional mapping matrix, the low-dimensional mapping data is visualized and analyzed to obtain the frequency response analysis result by constructing a visualization chart and observing the relationship between the data, such as when the power supply performance is high, the transmission efficiency is high and the equivalent inertia is excellent, so that relevant parameters such as damping can be obtained, and the power supply output in the system is stable data, and vice versa.

[0118] Furthermore, the embodiment of the present invention creates a frequency response analysis model of the photovoltaic grid-connected system based on the frequency response analysis results. The data model can reveal potential patterns, relationships and insights in the data, and help discover subtle information models that can help predict future trends, behaviors or results, thereby guiding decision making and planning.

[0119] As an embodiment of the present invention, creating a frequency response analysis model of the photovoltaic grid-connected system based on the frequency response analysis result includes: extracting analysis data corresponding to the frequency response analysis result, performing data preprocessing on the analysis data to obtain preprocessed data, using the preprocessed data to construct a regression model of the frequency response of the photovoltaic grid-connected system, performing model training on the regression model to obtain a training model, performing performance evaluation on the training model, obtaining a target model when the performance evaluation result meets a preset result, and performing model optimization on the target model to obtain a frequency response analysis model.

[0120] Optionally, the data preprocessing of the analysis data to obtain preprocessed data refers to cleaning and preprocessing the data, including processing missing values, outliers, duplicate values, and performing feature engineering, etc., which can be processed by interpolation method. The regression model of the frequency response of the photovoltaic grid-connected system constructed by using the preprocessed data is constructed by the multivariate linear regression function in the deep learning model. The regression model is trained to obtain the training model by using the analysis data for model training. The performance evaluation of the training model can use various indicators (such as accuracy, precision, recall rate, F1 score, etc.) to evaluate the model effect. When the performance evaluation result meets the preset result, the target model is obtained, such as the model accuracy is not less than 0.9. It can also be set according to the actual application scenario, and the target model is optimized to obtain the frequency response analysis model, which means adjusting the parameters of the model to improve the accuracy of the model analysis, which can be obtained by adjusting the model hyperparameters through feature engineering.

[0121] The embodiment of the present invention can understand the real-time operation data of the photovoltaic grid-connected system by collecting the real-time data of the photovoltaic grid-connected system.

[0122] Furthermore, the embodiment of the present invention can analyze the operation status of the photovoltaic grid-connected system in real time to see whether there are any abnormalities by performing real-time frequency response analysis on the photovoltaic grid-connected system based on the real-time data and utilizing the frequency response analysis model. If there are any operational abnormalities, corresponding countermeasures can be taken immediately to avoid accidents that cause loss of life and property.

[0123] like Figure 2 The figure shows a functional module diagram of a frequency response analysis system of a photovoltaic grid-connected system according to the present invention.

[0124] The frequency response analysis system 200 of a photovoltaic grid-connected system described in the present invention can be installed in an electronic device. According to the functions to be implemented, the frequency response analysis system of a photovoltaic grid-connected system can include a performance analysis module 201, a transmission efficiency analysis module 202, an equivalent inertia analysis module 203, and an analysis model creation module 204. The module described in the present invention can also be referred to as a unit, which refers to a series of computer program segments that can be executed by an electronic device processor and can complete fixed functions, which are stored in the memory of the electronic device.

[0125] In the embodiment of the present invention, the functions of each module / unit are as follows:

[0126] The performance analysis module 201 is used to collect component data and operating parameters of the photovoltaic grid-connected system, construct a photovoltaic array network of the photovoltaic grid-connected system based on the component data, and analyze the power supply performance of the photovoltaic grid-connected system based on the photovoltaic array network and the operating parameters;

[0127] The transmission efficiency analysis module 202 is used to identify the topology of the inverter in the photovoltaic grid-connected system, analyze the transmission damping of the inverter according to the topology, and analyze the transmission efficiency of the inverter according to the transmission damping;

[0128] The equivalent inertia analysis module 203 is used to construct a photovoltaic grid-connected model of the photovoltaic grid-connected system, analyze the frequency domain response characteristics of the photovoltaic grid-connected system using the photovoltaic grid-connected model, determine the frequency spectrum and frequency components of the photovoltaic grid-connected system based on the frequency domain response characteristics, and analyze the equivalent inertia of the photovoltaic grid-connected system based on the frequency spectrum and the frequency components;

[0129] The analysis model creation module 204 is used to perform frequency response analysis on the photovoltaic grid-connected system according to the power supply performance, the transmission efficiency and the equivalent inertia, obtain frequency response analysis results, create a frequency response analysis model of the photovoltaic grid-connected system according to the analysis results, collect real-time data of the photovoltaic grid-connected system, and perform real-time frequency response analysis on the photovoltaic grid-connected system using the frequency response analysis model based on the real-time data.

[0130] In the several embodiments provided by the present invention, it should be understood that the disclosed systems and methods can be implemented in other ways. For example, the system embodiments described above are only illustrative, for example, the division of the modules is only a logical function division, and there may be other division methods in actual implementation.

[0131] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0132] In addition, each functional module in each embodiment of the present invention may be integrated into one processing unit, each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of hardware plus software functional modules.

[0133] It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0134] Therefore, no matter from which point of view, the embodiments should be regarded as illustrative and non-restrictive, and the scope of the present invention is limited by the appended claims rather than the above description, so it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any attached figure mark in the claims should not be regarded as limiting the claims involved.

[0135] It should 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 such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0136] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features invented herein.

Claims

1. A frequency response analysis method for a photovoltaic grid-connected system, characterized in that: The method comprises: Collecting component data and operating parameters of a photovoltaic grid-connected system, constructing a photovoltaic array network of the photovoltaic grid-connected system based on the component data, and analyzing power supply performance of the photovoltaic grid-connected system based on the photovoltaic array network and the operating parameters; Identifying a topological structure of an inverter in the photovoltaic grid-connected system, analyzing a transmission damping of the inverter according to the topological structure, and analyzing a transmission efficiency of the inverter according to the transmission damping; Constructing a photovoltaic grid-connected model of the photovoltaic grid-connected system, analyzing the frequency domain response characteristics of the photovoltaic grid-connected system using the photovoltaic grid-connected model, determining a frequency spectrum and frequency components of the photovoltaic grid-connected system based on the frequency domain response characteristics, and analyzing the equivalent inertia of the photovoltaic grid-connected system based on the frequency spectrum and the frequency components; Performing frequency response analysis on the photovoltaic grid-connected system according to the power supply performance, the transmission efficiency and the equivalent inertia to obtain a frequency response analysis result, creating a frequency response analysis model of the photovoltaic grid-connected system according to the analysis result, collecting real-time data of the photovoltaic grid-connected system, and performing real-time frequency response analysis on the photovoltaic grid-connected system using the frequency response analysis model based on the real-time data; The analyzing the power supply performance of the photovoltaic grid-connected system based on the photovoltaic array network and the operating parameters includes: Analyzing output characteristics of the photovoltaic grid-connected system using the photovoltaic array network and the operating parameters; Based on the output characteristics, constructing a time-output current curve diagram of the photovoltaic grid-connected system; Based on the time-output current curve, analyzing the current output fluctuation of the photovoltaic grid-connected system; Analyzing the power supply performance of the photovoltaic grid-connected system based on the current output fluctuation; Analyzing the transmission efficiency of the inverter according to the transmission damping includes: Performing interval matching of the calculated value of the transmission damping with a pre-constructed damping threshold; determining a system oscillation characteristic of the inverter based on a matching result of the interval matching; analyzing a transmission efficiency of the inverter based on the system oscillation characteristics; The method of analyzing the frequency domain response characteristics of the photovoltaic grid-connected system by using the photovoltaic grid-connected model includes: Extracting input signals and output signals in the photovoltaic grid-connected model; Performing frequency domain conversion on the input signal and the output signal to obtain a converted input signal and a converted output signal; Performing frequency domain analysis on the conversion input signal and the conversion output signal to obtain a frequency domain analysis result; Based on the analysis results, analyzing the frequency domain response characteristics of the photovoltaic grid-connected system; The analyzing the equivalent inertia of the photovoltaic grid-connected system based on the frequency spectrum and the frequency components includes: After a disturbance signal is input to the photovoltaic grid-connected system, recording disturbance data of the photovoltaic grid-connected system; Constructing a response impact model of the photovoltaic grid-connected system according to the disturbance data, the frequency spectrum and the frequency components; Analyzing the equivalent inertia of the photovoltaic grid-connected system using the response impact model; The performing frequency response analysis on the photovoltaic grid-connected system according to the power supply performance, the transmission efficiency and the equivalent inertia to obtain a frequency response analysis result includes: Performing data conversion on the power supply performance, the transmission efficiency and the equivalent inertia to obtain conversion data; Calculating a covariance matrix of the transformed data, and performing eigenvalue decomposition on the covariance matrix to obtain decomposition eigenvalues; Performing data screening on the converted data based on the decomposed characteristic values ​​to obtain screened data; Mapping the screened data into a low-dimensional space to obtain low-dimensional mapping data; Visual analysis is performed on the low-dimensional mapping data to obtain a frequency response analysis result.

2. The method according to claim 1, characterized in that The step of constructing a photovoltaic array network of the photovoltaic grid-connected system based on the component data includes: Determining circuit parameters of the photovoltaic grid-connected system based on the component data; Constructing an initial layout of the photovoltaic grid-connected system; arranging a preconfigured photovoltaic model using the initial layout to obtain a target model; After the circuit parameters are input into the target model, the target model is activated to obtain a photovoltaic array network.

3. The method according to claim 1, characterized in that Analyzing the transmission damping of the inverter according to the topological structure includes: Determining a connection mode of resistors in the inverter based on the topological structure; Based on the connection method, calculating the resistance, inductance and capacitance of the resistor; The damping ratio of the inverter is calculated based on the resistance, the inductance and the capacitance using the following formula: ； in, represents the damping ratio, Represents resistance, represents inductance, Represents capacitance; The frequency range of the inverter is identified, and the transmission damping of the inverter is calculated based on the frequency range and the damping ratio using the following formula: ； in, represents the transmission damping, represents the damping ratio, Indicates the frequency range of the inverter.

4. The method according to claim 3, characterized in that The calculating the resistance, inductance and capacitance of the resistor based on the connection mode includes: When the connection mode is parallel connection, the resistance, inductance and capacitance of the resistor are calculated using the following formula; ； ； ； in, Represents resistance, represents inductance, Represents capacitance, represents the resistance of the first inductor in the resistor chain, represents the resistance of the second inductor in the resistor, represents the resistance of the nth inductor in the resistor chain, represents the inductance of the first inductor in the resistor, represents the inductance of the second inductor in the resistor, represents the inductance of the nth inductor in the resistor, represents the capacitance of the first inductor in the resistor, represents the capacitance of the second inductor in the resistor, represents the capacitance of the nth inductor in the resistor; When the connection mode is series connection, the resistance, inductance and capacitance of the resistor are calculated using the following formula: ； ； ； in, Represents resistance, represents inductance, Represents capacitance, represents the resistance of the first inductor in the resistor chain, represents the resistance of the second inductor in the resistor, represents the resistance of the nth inductor in the resistor chain, represents the inductance of the first inductor in the resistor, represents the inductance of the second inductor in the resistor, represents the inductance of the nth inductor in the resistor, represents the capacitance of the first inductor in the resistor, represents the capacitance of the second inductor in the resistor, Represents the capacitance of the nth inductor in the resistor.

5. A frequency response analysis system for a photovoltaic grid-connected system, the system implementing the method according to claim 1, characterized in that: The system comprises: A performance analysis module, used to collect component data and operating parameters of the photovoltaic grid-connected system, construct a photovoltaic array network of the photovoltaic grid-connected system based on the component data, and analyze the power supply performance of the photovoltaic grid-connected system based on the photovoltaic array network and the operating parameters; A transmission efficiency analysis module, used to identify the topology of the inverter in the photovoltaic grid-connected system, analyze the transmission damping of the inverter according to the topology, and analyze the transmission efficiency of the inverter according to the transmission damping; an equivalent inertia analysis module, used to construct a photovoltaic grid-connected model of the photovoltaic grid-connected system, analyze the frequency domain response characteristics of the photovoltaic grid-connected system using the photovoltaic grid-connected model, determine the frequency spectrum and frequency components of the photovoltaic grid-connected system based on the frequency domain response characteristics, and analyze the equivalent inertia of the photovoltaic grid-connected system based on the frequency spectrum and the frequency components; An analysis model creation module is used to perform frequency response analysis on the photovoltaic grid-connected system according to the power supply performance, the transmission efficiency and the equivalent inertia to obtain frequency response analysis results, create a frequency response analysis model of the photovoltaic grid-connected system according to the analysis results, collect real-time data of the photovoltaic grid-connected system, and perform real-time frequency response analysis on the photovoltaic grid-connected system using the frequency response analysis model based on the real-time data.

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