A Photovoltaic Device Networking Control Method and System

Abstract

The present invention discloses a networking control method and system for photovoltaic devices, which relates to the technical field of photovoltaic power generation. When the system operates, the data acquisition module ensures high-precision current signal acquisition. The digital signal processing module removes noise and enhances signal quality through low-pass filtering and convolution operations. The signal conversion module comprehensively analyzes spectrum information using FFT transformation. The data analysis module extracts harmonic components and calculates the total harmonic distortion rate THD, providing a precise filter adjustment scheme. The regulation module calculates the power factor Pf and the flicker variable Fb, and conducts a comprehensive power quality assessment in combination with THD to ensure that the system operates in the best state. This system effectively solves the problems of low current signal acquisition accuracy, unstable signal processing, difficult monitoring of harmonic distortion, and difficult comprehensive assessment of power quality in the traditional networking of photovoltaic devices, and significantly improves the power output quality of photovoltaic devices and the reliability and economic benefits of the overall power system.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation, and specifically provides a photovoltaic device networking control method and system. Background Art

[0002] Photovoltaic device networking integrates solar panel arrays, energy storage devices, photovoltaic inverters, and grid connection devices to effectively manage the operation of a photovoltaic power generation system, improve energy utilization efficiency, and enhance the stability of the power supply system.

[0003] Currently, in the control of photovoltaic device networking, there are some deficiencies, including insufficient power quality management and current waveform distortion problems. The photovoltaic system often faces harmonic distortion in the current waveform during power generation, which reduces the power factor of the power grid, affects power transmission efficiency and stability. Traditional monitoring and control means lack real-time and accurate identification of current waveform distortion and effective harmonic suppression measures, resulting in abnormal operation of the power system under high load and unstable conditions.

[0004] In the current power system, the abnormal effects caused by harmonic distortion and current waveform problems include energy waste in the power grid and unstable operation of equipment. Harmonic distortion may cause equipment damage, unstable power grid frequency, and degraded power quality, thereby affecting the normal power consumption of users and the long-term reliability of the power system. The lack of targeted current waveform distortion monitoring and management strategies makes the power system unable to achieve an efficient and stable operating state in the face of increasingly complex power demands and environmental conditions. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a photovoltaic device networking control method and system, which solves the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention is realized through the following technical solutions: A photovoltaic device networking control system includes a data acquisition module, a digital signal processing module, a signal conversion module, a data analysis module, a regulation module, and a monitoring module;

[0007] The data acquisition module collects current signals by installing current sensors at the output end of photovoltaic devices, converts the current signals collected at fixed intervals into digital signals, and synchronously integrates the sampling frequency Fs and the number of sampling points N at fixed intervals to form a digital signal data group X;

[0008] The digital signal processing module preprocesses the digital signal data set X, including removing high-frequency noise in the digital signal data set X using a low-pass filter, synchronously normalizing the digital signal data set X after noise removal by the low-pass filter, and then performing a convolution operation on the normalized digital signal data set X with the impulse response function of the low-pass filter to obtain the digital signal I after the convolution operation. final ;

[0009] The signal conversion module performs an FFT transformation on the filtered digital signal I final according to the sampling frequency Fs and the number of sampling points N to obtain spectral information, including frequency (f, p), amplitude |X(f, p)|, and phase angle to form a spectral feature vector set Fk;

[0010] The data analysis module extracts the amplitudes and phase angles of each harmonic in the current signal from the spectral feature vector set Fk, then calculates the total harmonic distortion rate THD through harmonic distortion calculation, and matches it with a preset total harmonic distortion fluctuation threshold Z to obtain a filter adjustment evaluation scheme;

[0011] The regulation module calculates the power factor Pf and the flicker amount Fb of the voltage by obtaining the root mean square values of the voltage and current, synchronously fits the total harmonic distortion rate THD, the power factor Pf, and the flicker amount Fb to obtain a power quality evaluation index Pgzs, and matches it with a preset power quality fitting evaluation threshold L to obtain a regulation power quality evaluation scheme.

[0012] Preferably, the data acquisition module includes a current sensor unit and a data conversion integration unit;

[0013] The current sensor unit collects the current signal by installing a current sensor at the output end of the photovoltaic device. The current sensor includes a Hall effect sensor and collects according to a fixed acquisition period T. The current signal I(t) at continuous time points t is collected according to the sampling frequency Fs and the number of sampling points N set by the fixed acquisition period T;

[0014] The data conversion integration unit converts the continuous current signal I(t) obtained according to the sampling frequency Fs and the number of sampling points N within the fixed acquisition period T by using an analog-to-digital converter, obtains a continuous digital signal I[N] through the conversion, and then integrates the digital signal I[N] into a digital signal data set X according to the fixed acquisition period T.

[0015] Preferably, the digital signal processing module includes a filtering unit, a normalization unit, and a convolution unit;

[0016] The filtering unit preprocesses the digital signal data set X, including using a low-pass filter to remove high-frequency noise in the digital signal data set X, and obtaining the filtered digital signal X filtered [N];

[0017] The normalization unit synchronously normalizes the digital signal data set X filtered [N] after the noise removal by the low-pass filter, to eliminate the difference in the amplitude of the digital signal data set X, and obtain the normalized digital signal X norm [N];

[0018] The convolution unit uses convolution operation to convolve the impulse response function of the low-pass filter with the normalized digital signal data set X norm [N], and obtains the digital signal I after the convolution operation final .

[0019] Preferably, the signal conversion module includes a fast Fourier transform unit and a feature vector set generation unit;

[0020] The fast Fourier transform unit performs FFT transformation on the filtered digital signal I according to the sampling frequency Fs and the number of sampling points N final to convert the time-domain signal into a frequency-domain signal, and obtains spectrum information, including frequency (f, p), amplitude |X(f, p)| and phase angle to form a spectrum feature vector set Fk.

[0021] Preferably, the data analysis module includes a harmonic calculation unit and a harmonic matching unit;

[0022] The harmonic calculation unit extracts the amplitude |X(f, p)| and phase angle of each harmonic in the current signal from the spectrum feature vector set Fk and then performs harmonic distortion calculation to obtain the total harmonic distortion rate THD;

[0023] The harmonic matching unit matches the preset total harmonic distortion fluctuation threshold Z with the total harmonic distortion rate THD to obtain a filter adjustment evaluation scheme.

[0024] Preferably,

[0025] The filter adjustment evaluation scheme is obtained through the following matching method:

[0026] When the total harmonic distortion rate THD ≥ the total harmonic distortion fluctuation threshold Z, obtain the harmonic distortion evaluation result, mark the filter with a to-be-adjusted mark, and prompt and execute the harmonic suppression strategy;

[0027] The total harmonic distortion rate THD < the total harmonic distortion fluctuation threshold Z, obtain the harmonic undistorted evaluation result, mark the filter as the non-adjustment mark, and do not give a prompt or execute the harmonic suppression strategy.

[0028] Preferably, the regulation module includes a calculation and fitting unit and a power quality evaluation unit;

[0029] The calculation and fitting unit calculates the power factor Pf and the flicker variable Fb of the voltage by obtaining the root mean square values of the voltage and the current, and synchronously fits the total harmonic distortion rate THD, the power factor Pf, and the flicker variable Fb to obtain the power quality evaluation index Pgzs.

[0030] Preferably,

[0031] The power quality evaluation unit matches the preset power quality fitting evaluation threshold L with the power quality evaluation index Pgzs to obtain a regulation power quality evaluation scheme, and performs specific execution and iteration according to the scheme.

[0032] Preferably, the regulation power quality evaluation scheme is obtained through the following evaluation method:

[0033] The power quality evaluation index Pgzs < the power quality fitting evaluation threshold L, obtain the qualified result of the regulation power quality evaluation, and mark and record the qualified result of the power quality;

[0034] The power quality evaluation index Pgzs ≥ the power quality fitting evaluation threshold L, obtain the unqualified result of the regulation power quality evaluation, mark and record the unqualified power quality, iteratively obtain the total harmonic distortion rate THD and execute the filter adjustment evaluation scheme until the content of the regulation power quality evaluation scheme is marked as the qualified result of the regulation power quality evaluation, and also include synchronously calculating the compensation current I comp (t) to regulate the harmonic distortion situation.

[0035] A photovoltaic device networking control method includes the following steps:

[0036] Step 1: The data acquisition module collects the current signal by installing a current sensor at the output end of the photovoltaic device, converts the current signal collected at a fixed period into a digital signal, and synchronously integrates the sampling frequency Fs and the number of sampling points N at a fixed period to form a digital signal data group X;

[0037] Step 2: The digital signal processing module preprocesses the digital signal data group X, including removing high-frequency noise in the digital signal data group X using a low-pass filter, synchronously normalizing the digital signal data group X after noise removal by the low-pass filter, and then performing a convolution operation on the normalized digital signal data group X with the impulse response function of the low-pass filter to obtain the digital signal I after the convolution operation. final ;

[0038] Step 3: The signal conversion module performs an FFT transformation on the filtered digital signal I according to the sampling frequency Fs and the number of sampling points N to obtain spectral information, including frequency (f, p), amplitude |X(f, p)|, and phase angle final to form a spectral feature vector set Fk. ;

[0039] Step 4: The data analysis module extracts the amplitudes and phase angles of each harmonic in the current signal from the spectral feature vector set Fk, then calculates the total harmonic distortion rate THD through harmonic distortion calculation, and matches it with the preset total harmonic distortion fluctuation threshold Z to obtain a filter adjustment evaluation scheme.

[0040] Step 5: The regulation module calculates the power factor Pf and the flicker variable Fb by obtaining the root mean square values of voltage and current, synchronously fits the total harmonic distortion rate THD, the power factor Pf, and the flicker variable Fb to obtain a power quality evaluation index Pgzs, and matches it with the preset power quality fitting evaluation threshold L to obtain a regulation power quality evaluation scheme.

[0041] The present invention provides a photovoltaic device networking control method and system, having the following beneficial effects:

[0042] (1) During system operation, the data acquisition module ensures high-precision current signal acquisition. The digital signal processing module removes noise and enhances signal quality through low-pass filtering and convolution operations. The signal conversion module comprehensively analyzes spectral information using FFT transformation. The data analysis module extracts harmonic components and calculates the total harmonic distortion rate THD to provide an accurate filter adjustment scheme. The regulation module calculates the power factor Pf and the flicker variable Fb, and combines THD for comprehensive power quality evaluation to ensure that the system operates in the best state. This system effectively solves the problems of low current signal acquisition accuracy, unstable signal processing, difficult monitoring of harmonic distortion, and difficult comprehensive evaluation of power quality in traditional photovoltaic device networking, and significantly improves the power output quality of photovoltaic devices and the reliability and economic benefits of the overall power system.

[0043] (2) The use of Hall effect sensors and analog-to-digital converters ensures high-precision, high-frequency current signal acquisition and digital signal conversion, solving the problem of low signal acquisition accuracy in traditional systems. The digital signal processing module removes high-frequency noise through low-pass filtering, normalization, and convolution operations, enhancing signal quality and consistency, making subsequent analysis more reliable. The signal conversion module uses fast Fourier transform (FFT) to convert time domain signals into frequency domain signals, providing detailed spectrum information, including frequency (f, p), amplitude |X(f, p)|, and phase angle. Effectively identify and analyze harmonic components in current signals.

[0044] (3) Extract the amplitude |X(f,p)| and phase angle of each harmonic The total harmonic distortion rate THD is accurately calculated and used as the benchmark for harmonic distortion evaluation; the harmonic matching unit matches the calculated THD with the preset total harmonic distortion fluctuation threshold Z. When THD exceeds Z, the system automatically marks the filter as pending adjustment and prompts and executes the harmonic suppression strategy. Otherwise, no adjustment is made. This ensures real-time monitoring and dynamic adjustment of harmonic distortion, effectively solving the problem of difficult accurate evaluation and timely regulation of harmonic distortion in traditional photovoltaic equipment networking systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a schematic diagram of a photovoltaic equipment networking control system block diagram of the present invention;

[0046] Figure 2 The figure is a schematic diagram of the steps of a photovoltaic equipment networking control method of the present invention. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0048] Example 1

[0049] The present invention provides a photovoltaic equipment networking control system, please refer to Figure 1 , including data acquisition module, digital signal processing module, signal conversion module, data analysis module, control module and monitoring module;

[0050] The data acquisition module collects current signals by installing current sensors at the output end of the photovoltaic device, converts the current signals collected at fixed intervals into digital signals, and synchronously integrates the sampling frequency Fs and the number of sampling points N at fixed intervals to form a digital signal data group X;

[0051] The digital signal processing module preprocesses the digital signal data group X, including using a low-pass filter to remove high-frequency noise in the digital signal data group X, synchronously normalizing the digital signal data group X after noise removal by the low-pass filter, and then using a convolution operation to convolve the impulse response function of the low-pass filter with the normalized digital signal data group X to obtain the digital signal I after the convolution operation final ;

[0052] The signal conversion module performs FFT transformation on the filtered digital signal I according to the sampling frequency Fs and the number of sampling points N final to obtain spectrum information, including frequency (f, p), amplitude |X(f, p)|, and phase angle to form a spectrum feature vector set Fk;

[0053] The data analysis module extracts the amplitudes and phase angles of each harmonic in the current signal from the spectrum feature vector set Fk, then calculates the total harmonic distortion rate THD through harmonic distortion calculation, and matches it with the preset total harmonic distortion fluctuation threshold Z to obtain a filter adjustment evaluation scheme;

[0054] The regulation module calculates the power factor Pf and the flicker variable Fb by obtaining the root mean square values of voltage and current, synchronously fits the total harmonic distortion rate THD, the power factor Pf, and the flicker variable Fb to obtain a power quality evaluation index Pgzs, and matches it with the preset power quality fitting evaluation threshold L to obtain a regulation power quality evaluation scheme.

[0055] In this embodiment, the data acquisition module ensures high-precision current signal acquisition. The digital signal processing module removes noise and enhances signal quality through low-pass filtering and convolution operations; the signal conversion module comprehensively analyzes spectrum information using FFT transformation. The data analysis module extracts harmonic components and calculates the total harmonic distortion rate THD, providing an accurate filter adjustment scheme; the regulation module calculates the power factor Pf and the flicker variable Fb, and conducts a comprehensive power quality evaluation in combination with THD to ensure that the system operates in the best state. This system effectively solves the problems of low current signal acquisition accuracy, unstable signal processing, difficult monitoring of harmonic distortion, and difficult comprehensive evaluation of power quality in the traditional photovoltaic device networking, significantly improving the power output quality of photovoltaic devices and the reliability and economic benefits of the overall power system.

[0056] Embodiment 2

[0057] This embodiment is an explanatory description based on Embodiment 1. Please refer to Figure 1 , specifically: The data acquisition module includes a current sensor unit and a data conversion integration unit;

[0058] The current sensor unit collects current signals by installing a current sensor at the output end of the photovoltaic device. The current sensor includes a Hall effect sensor, and collects according to a fixed acquisition period T. The sampling frequency Fs and the number of sampling points N set in the fixed acquisition period T are used to collect the current signal I(t) at consecutive time points t;

[0059] The data conversion integration unit converts the continuous current signal I(t) obtained by the sampling frequency Fs and the number of sampling points N within the fixed acquisition period T by using an analog-to-digital converter, obtains a continuous digital signal I[N] through conversion, and then integrates the digital signal I[N] into a digital signal data group X according to the fixed acquisition period T. The digital signal data group X includes X = {I[0], I[1], I[2],..., I[N - 1]}.

[0060] The digital signal processing module includes a filtering unit, a normalization unit, and a convolution unit;

[0061] The filtering unit preprocesses the digital signal data group X, including using a low-pass filter to remove high-frequency noise in the digital signal data group X, and obtains the filtered digital signal X filtered [N];

[0062] The high-frequency noise in the digital signal data group X is filtered out through the following low-pass filtering formula:

[0063]

[0064] In the formula, X filtered [N] represents the filtered digital signal, X[N] represents the unfiltered digital signal data group, h[k] represents the impulse response function of the low-pass filter, M represents the filter length, k represents the k-th coefficient of the filter, and the specific range is k[0, M - 1];

[0065] The normalization unit synchronously normalizes the digital signal data group X filtered [N] after noise removal by the low-pass filter to eliminate the difference in the amplitude of the digital signal data group X, and obtains the normalized digital signal X norm [N];

[0066] The difference in the amplitude of the digital signal data group X is eliminated through the following normalization formula:

[0067]

[0068] where X norm [N] represents the digital signal after normalization processing, and X filtered [N] represents the digital signal after filtering, and X min represents the minimum value of the digital signal after filtering, and X max represents the maximum value of the digital signal after filtering;

[0069] The convolution unit uses convolution operation to convolve the impulse response function of the low-pass filter with the digital signal data set X norm [N] after normalization processing to obtain the digital signal I final after convolution operation.

[0070] The signal conversion module includes a fast Fourier transform unit and a feature vector set generation unit;

[0071] The fast Fourier transform unit performs FFT transformation on the filtered digital signal I final according to the sampling frequency Fs and the number of sampling points N to convert the time-domain signal into a frequency-domain signal, obtaining spectrum information, including frequency (f, p), amplitude |X(f, p)|, and phase angle to form a spectrum feature vector set Fk, where

[0072] where, (f, p) is obtained by formula calculation, and Fs represents the sampling frequency.

[0073] The amplitude |X(f, p)| is obtained through the following calculation formula:

[0074]

[0075] In the formula, |X(f, p)| represents the amplitude of the p-th frequency component, specifically representing the intensity of the signal at the frequency (f, p), Re[X(f, p)] represents the real part of the spectrum value X(f, p), specifically representing the real number part of the signal at the frequency (f, p), Im(X(f, p)) represents the imaginary part of the spectrum value X(f, p), specifically representing the imaginary number part of the signal at the frequency (f, p), and the amplitude |X(f, p)| represents the intensity or energy of the signal at the corresponding frequency (f, p). By calculating the amplitude of each frequency component, the distribution of the signal at each frequency can be understood. At the same time, the magnitude of the amplitude |X(f, p)| reflects the contribution degree of the signal at that frequency. A larger amplitude indicates that the frequency component occupies a larger proportion in the signal;

[0076] The phase angle is obtained through the following calculation formula:

[0077]

[0078] In the formula, represents the phase angle of the p-th frequency component, specifically representing the phase angle of the signal at the frequency (f, p). The phase angle represents the phase information of the signal at the corresponding frequency (f, p). The phase describes the timing characteristics of the signal, that is, the starting position of the signal at this frequency. The value range of the phase angle includes [-π, π], representing the relative position of the signal on the time axis.

[0079] In this embodiment, by adopting a Hall effect sensor and an analog-to-digital converter, high-precision and high-frequency current signal acquisition and digital signal conversion are ensured, and the problem of low signal acquisition accuracy in the traditional system is solved; the digital signal processing module removes high-frequency noise, enhances signal quality and consistency through low-pass filtering, normalization processing and convolution operations, making subsequent analysis more reliable; the signal conversion module converts the time-domain signal into a frequency-domain signal using the fast Fourier transform FFT, providing detailed spectrum information, including frequency (f, p), amplitude |X(f, p)| and phase angle to effectively identify and analyze the harmonic components in the current signal.

[0080] Embodiment 3

[0081] This embodiment is an explanatory description based on Embodiment 2. Please refer to Figure 1 , specifically: the data analysis module includes a harmonic calculation unit and a harmonic matching unit;

[0082] The harmonic calculation unit extracts the amplitudes |X(f, p)| and phase angles of each harmonic in the current signal from the spectral feature vector set Fk and then calculates the total harmonic distortion rate THD through harmonic distortion calculation;

[0083] The harmonic matching unit matches the preset total harmonic distortion fluctuation threshold Z with the total harmonic distortion rate THD to obtain a filter adjustment evaluation scheme;

[0084] The filter adjustment evaluation scheme is obtained through the following matching method:

[0085] When the total harmonic distortion rate THD ≥ the total harmonic distortion fluctuation threshold Z, a harmonic distortion evaluation result is obtained, the filter is marked as a to-be-adjusted mark, and a harmonic suppression strategy is prompted and executed;

[0086] When the total harmonic distortion rate THD < the total harmonic distortion fluctuation threshold Z, a harmonic non-distortion evaluation result is obtained, the filter is marked as a non-adjusted mark, and no harmonic suppression strategy is prompted and executed.

[0087] The total harmonic distortion rate THD is obtained through the following calculation formula:

[0088]

[0089] In the formula, X(f, 1) represents the fundamental wave amplitude, which is specifically the reference for harmonic distortion calculation and also represents the signal amplitude at frequency (f, 1). X(f, p) represents the amplitude of the p-th harmonic, specifically representing the signal amplitude at frequency (f, p). g represents the harmonic serial number, starting from g = 2, because g = 1 represents the fundamental wave. represents the infinite sum from g = 2 to g = ∞, where ∞ specifically represents all harmonic numbers higher than the fundamental wave.

[0090] In this embodiment, the amplitudes |X(f, p)| and phase angles of each harmonic are extracted. The total harmonic distortion rate THD is accurately calculated and used as the benchmark for harmonic distortion evaluation. The harmonic matching unit matches the calculated THD with the preset total harmonic distortion fluctuation threshold Z. When THD exceeds Z, the system automatically marks the filter as the state to be adjusted, and prompts and executes the harmonic suppression strategy for regulation, otherwise no adjustment is made. This ensures the real-time monitoring and dynamic adjustment of harmonic distortion, effectively solving the problem that harmonic distortion in traditional photovoltaic device networking systems is difficult to accurately evaluate and timely regulate.

[0091] Embodiment 4

[0092] This embodiment is an explanatory description based on Embodiment 3. Please refer to Figure 1 , specifically: The regulation module includes a calculation and fitting unit and a power quality evaluation unit;

[0093] The calculation and fitting unit calculates the power factor Pf and the flicker variable Fb of the voltage by obtaining the root mean square values of the voltage and current, and synchronously fits the total harmonic distortion rate THD, the power factor Pf, and the flicker variable Fb to obtain the power quality evaluation index Pgzs.

[0094] The power quality evaluation index Pgzs is obtained through the following fitting calculation formula:

[0095] Pgzs = α * THD + β * Pf + χ * Fb;

[0096] In the formula, α, β, and χ respectively represent the preset weight values of the total harmonic distortion rate THD, the power factor Pf, and the flicker variable Fb;

[0097] The power factor Pf is calculated and obtained through the following formula:

[0098]

[0099] In the formula, Py represents the active power, and through Py = V rms * I rms*Obtained by the cos(θ) formula, where V rms represents the root mean square value of the voltage, obtained by measuring and calculating the root mean square value through a voltage sensor, I rms represents the root mean square value of the current, obtained by calculating the root mean square value through a current sensor strategy; Sz represents the apparent power, through Sz = V rms *I rms Obtained by the formula calculation;

[0100] The power quality assessment unit matches the preset power quality fitting assessment threshold L with the power quality assessment index Pgzs to obtain a regulation power quality assessment plan, and performs specific execution and iteration according to the plan.

[0101] The regulation power quality assessment plan is obtained through the following assessment methods:

[0102] When the power quality assessment index Pgzs < the power quality fitting assessment threshold L, obtain the qualified result of the regulation power quality assessment, and mark and record the qualified result of the power quality;

[0103] When the power quality assessment index Pgzs ≥ the power quality fitting assessment threshold L, obtain the unqualified result of the regulation power quality assessment, mark and record the unqualified power quality, iteratively obtain the total harmonic distortion rate THD and execute the filter adjustment assessment plan until the content of the regulation power quality assessment plan is marked as the qualified result of the regulation power quality assessment. It also includes synchronously calculating the compensation current I comp (t) to regulate the harmonic distortion situation, and injecting the calculated compensation current I comp (t) into the power system in real time to cancel the harmonic current and achieve harmonic suppression and power quality improvement;

[0104] The compensation current I comp (t) is obtained through the following calculation formula:

[0105]

[0106] In the formula, I comp (t) represents the compensation current, specifically representing the current value compensated at time t, U represents the total harmonic order, specifically representing the highest harmonic order for harmonic calculation, |X(f,p)| represents the amplitude of the pth harmonic, specifically representing the signal amplitude at the frequency (f,p), g represents the harmonic serial number, starting from g = 2 because g = 1 represents the fundamental wave, t represents the time point, specifically representing the time point of the compensation current, represents the time characteristic of the gth harmonic component, specifically representing the change waveform of the gth harmonic component to the time point t, specifically a sine wave with a frequency of (f,p), an amplitude of |X(f,p), and a phase angle of represents the phase angle of the p-th harmonic, specifically representing the signal phase at the frequency (f,p). sin represents the sine function, which is specifically used to represent the waveform of the harmonic component. 2π(f,p)*t represents the angular frequency of the g-th harmonic multiplied by the time t, specifically describing the phase angle position of the harmonic at time t. The angular frequency 2π(f,p) is a frequency representation in radians per second. The harmonic components in the current signal refer to the frequency components other than the fundamental wave, and the harmonic frequencies of the frequency components are integer multiples of the fundamental wave frequency;

[0107] Among them, the compensated current I comp (t) is used to compensate the harmonic current I comp (t) in the power system in real time. The magnitude and direction of the compensated current I comp (t) are opposite to those of the harmonic current, thereby achieving harmonic suppression and power quality improvement.

[0108] In this embodiment, the total harmonic distortion rate THD, power factor Pf, and flicker variable Fb are fitted to obtain the power quality evaluation index Pgzs, which is then matched with the preset power quality fitting evaluation threshold L to obtain the power quality regulation evaluation scheme. The power quality is evaluated for compliance, and a regulation scheme is generated accordingly, marked as qualified or unqualified for power quality, and the total harmonic distortion rate THD and the filter are iteratively adjusted until the qualified standard is reached. Through precise calculation and intelligent matching, comprehensive monitoring and optimization of power quality are achieved.

[0109] Embodiment 5

[0110] A method for networking control of photovoltaic devices, please refer to Figure 2 , specifically: including the following steps:

[0111] Step 1: The data acquisition module collects the current signal by installing a current sensor at the output end of the photovoltaic device, converts the current signal collected at a fixed period into a digital signal, and synchronously integrates the sampling frequency Fs and the number of sampling points N at the fixed period to form a digital signal data group X;

[0112] Step 2: The digital signal processing module preprocesses the digital signal data group X, including using a low-pass filter to remove the high-frequency noise in the digital signal data group X, synchronously normalizing the digital signal data group X after removing the low-pass filter noise, and then using a convolution operation to convolve the impulse response function of the low-pass filter with the normalized digital signal data group X to obtain the digital signal I final ;

[0113] Step 3: The signal conversion module filters the digital signal I according to the sampling frequency Fs and the number of sampling points N finalPerform FFT transformation to obtain spectrum information, including frequency (f, p), amplitude |X(f, p)|, and phase angle Form a spectrum feature vector set Fk;

[0114] Step 4: The data analysis module extracts the amplitudes and phase angles of each harmonic in the current signal from the spectrum feature vector set Fk, then calculates the total harmonic distortion rate THD through harmonic distortion calculation, and matches it with the preset total harmonic distortion fluctuation threshold Z to obtain a filter adjustment evaluation scheme;

[0115] Step 5: The regulation module calculates the power factor Pf and flicker amount Fb of the voltage by obtaining the root mean square values of the voltage and current, synchronously fits the total harmonic distortion rate THD, power factor Pf, and flicker amount Fb to obtain the power quality evaluation index Pgzs, and matches it with the preset power quality fitting evaluation threshold L to obtain a regulation power quality evaluation scheme.

[0116] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A photovoltaic equipment networking control system, characterized in that: It includes data acquisition module, digital signal processing module, signal conversion module, data analysis module, control module and monitoring module; The data acquisition module collects current signals by installing a current sensor at the output end of the photovoltaic device, converts the current signals collected at a fixed period into digital signals, and simultaneously integrates the sampling frequency Fs and the number of sampling points N of the fixed period to form a digital signal data group X; The digital signal processing module pre-processes the digital signal data set X, including using a low-pass filter to remove high-frequency noise in the digital signal data set X, and simultaneously normalizing the digital signal data set X after the low-pass filter noise is removed, and then using a convolution operation to convolve the impulse response function of the low-pass filter with the normalized digital signal data set X to obtain a digital signal I after the convolution operation. final ; The signal conversion module converts the filtered digital signal I according to the sampling frequency Fs and the number of sampling points N. final Perform FFT transformation to obtain spectrum information, including frequency (f, p), amplitude |X(f, p)| and phase angle Composed of spectrum feature vector set Fk; The data analysis module extracts the amplitude and phase angle of each harmonic in the current signal from the spectrum feature vector set Fk, and then performs harmonic distortion calculation to obtain the total harmonic distortion rate THD, and matches it with the preset total harmonic distortion fluctuation threshold Z to obtain the filter adjustment evaluation plan; The control module calculates the voltage power factor Pf and flicker amount Fb by obtaining the root mean square value of the voltage and current, and simultaneously fits the total harmonic distortion rate THD, the power factor Pf and the flicker amount Fb to obtain the power quality assessment index Pgzs, and matches it with the preset power quality fitting assessment threshold L to obtain the control power quality assessment scheme.

2. A photovoltaic equipment networking control system according to claim 1, characterized in that: The data acquisition module includes a current sensor unit and a data conversion integrated unit; The current sensor unit collects current signals by installing a current sensor at the output end of the photovoltaic device. The current sensor includes a Hall effect sensor. The current signal is collected according to a fixed collection period T. The sampling frequency Fs and the number of sampling points N set by the fixed collection period T collect the current signal I(t) at continuous time points t. The data conversion integrated unit converts the continuous current signal I(t) obtained by the sampling frequency Fs and the number of sampling points N within a fixed acquisition period T by using an analog-to-digital converter, obtains a continuous digital signal I[N] through the conversion, and then integrates the digital signal I[N] into a digital signal data group X according to the fixed acquisition period T.

3. A photovoltaic equipment networking control system according to claim 1, characterized in that: The digital signal processing module includes a filtering unit, a normalization unit and a convolution unit; The filtering unit pre-processes the digital signal data set X, including using a low-pass filter to remove high-frequency noise in the digital signal data set X, and obtaining a filtered digital signal X filtered [N]; The standardization unit synchronously processes the digital signal data set X after the low-pass filter noise is removed. filtered [N] Perform normalization to eliminate the difference in the amplitude of the digital signal data group X and obtain the normalized digital signal X norm [N]; The convolution unit uses a convolution operation to combine the impulse response function of the low-pass filter with the normalized digital signal data set X norm [N] performs convolution operation to obtain the digital signal I after convolution operation final .

4. A photovoltaic equipment networking control system according to claim 3, characterized in that: The signal conversion module includes a fast Fourier transform unit and a feature vector set generation unit; The fast Fourier transform unit transforms the filtered digital signal I according to the sampling frequency Fs and the number of sampling points N. final Perform FFT transformation to convert the time domain signal into a frequency domain signal to obtain spectrum information, including frequency (f, p), amplitude |X(f, p) and phase angle Form the spectrum feature vector set Fk.

5. A photovoltaic equipment networking control system according to claim 4, characterized in that: The data analysis module includes a harmonic calculation unit and a harmonic matching unit; The harmonic calculation unit extracts the amplitude |X(f,p) and phase angle of each harmonic in the current signal from the spectrum feature vector set Fk Then perform harmonic distortion calculation to obtain the total harmonic distortion rate THD; The harmonic matching unit matches the preset total harmonic distortion fluctuation threshold Z with the total harmonic distortion rate THD to obtain a filter adjustment evaluation scheme.

6. A photovoltaic equipment networking control system according to claim 1, characterized in that: The filter adjustment evaluation scheme is obtained by the following matching method: Total harmonic distortion rate THD ≥ total harmonic distortion fluctuation threshold Z, obtain harmonic distortion evaluation results, mark the filter as a mark to be adjusted, and prompt and execute the control harmonic suppression strategy; The total harmonic distortion rate THD is less than the total harmonic distortion fluctuation threshold Z, and the harmonic undistorted evaluation result is obtained. The filter is marked as not to be adjusted, and no prompt is given or the harmonic suppression strategy is executed.

7. A photovoltaic equipment networking control system according to claim 6, characterized in that: The control module includes a calculation and fitting unit and a power quality assessment unit; The calculation fitting unit calculates the voltage power factor Pf and the flicker amount Fb by acquiring the root mean square value of the voltage and the current, and simultaneously fits the total harmonic distortion rate THD, the power factor Pf and the flicker amount Fb to obtain the power quality evaluation index Pgzs.

8. A photovoltaic equipment networking control system according to claim 1, characterized in that: The power quality assessment unit matches the preset power quality fitting assessment threshold L with the power quality assessment index Pgzs, obtains a control power quality assessment scheme, and performs specific execution and iteration according to the scheme.

9. A photovoltaic equipment networking control system according to claim 8, characterized in that: The control power quality assessment scheme is obtained through the following assessment method: The power quality assessment index Pgzs is less than the power quality fitting assessment threshold L, and the qualified result of the regulated power quality assessment is obtained, and the qualified result of the power quality is marked and recorded; The power quality assessment index Pgzs ≥ the power quality fitting assessment threshold L, obtain the unqualified result of the regulated power quality assessment, mark and record the unqualified power quality, iteratively obtain the total harmonic distortion rate THD and execute the filter adjustment assessment plan until the content of the regulated power quality assessment plan is marked as the qualified result of the regulated power quality assessment, and also includes synchronously calculating the compensation current I comp (t) to adjust the harmonic distortion.

10. A photovoltaic equipment networking control method, applied to a photovoltaic equipment networking control system according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: The data acquisition module collects current signals by installing a current sensor at the output end of the photovoltaic device, converts the current signals collected at a fixed period into digital signals, and simultaneously integrates the fixed period sampling frequency Fs and the number of sampling points N to form a digital signal data group X; Step 2: The digital signal processing module preprocesses the digital signal data set X, including using a low-pass filter to remove high-frequency noise in the digital signal data set X, and simultaneously normalizing the digital signal data set X after the low-pass filter noise is removed, and then using a convolution operation to convolve the impulse response function of the low-pass filter with the normalized digital signal data set X to obtain a digital signal I after the convolution operation. final ; Step 3: The signal conversion module converts the filtered digital signal I according to the sampling frequency Fs and the number of sampling points N final Perform FFT transformation to obtain spectrum information, including frequency (f, p), amplitude |X(f, p)| and phase angle Composed of spectrum feature vector set Fk; Step 4: The data analysis module extracts the amplitude and phase angle of each harmonic in the current signal from the spectrum feature vector set Fk, and then calculates the harmonic distortion to obtain the total harmonic distortion rate THD, and matches it with the preset total harmonic distortion fluctuation threshold Z to obtain the filter adjustment evaluation plan; Step 5: The control module calculates the voltage power factor Pf and flicker Fb by obtaining the root mean square value of the voltage and current, and simultaneously fits the total harmonic distortion rate THD, power factor Pf and flicker Fb to obtain the power quality assessment index Pgzs, and matches it with the preset power quality fitting assessment threshold L to obtain the control power quality assessment plan.

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