Photovoltaic equipment networking control method and system

Abstract

The invention discloses a photovoltaic equipment networking control method and system, and relates to the technical field of photovoltaic power generation, when the system runs, a data acquisition module ensures high-precision current signal acquisition, and a digital signal processing module removes noise and enhances signal quality through low-pass filtering and convolution operation; the signal conversion module comprehensively analyzes frequency spectrum information by using FFT (Fast Fourier Transform), and the data analysis module extracts harmonic components, calculates a total harmonic distortion rate THD and provides an accurate filter adjustment scheme; the regulation and control module calculates a power factor Pf and a flash variable Fb, comprehensive power quality evaluation is carried out in combination with THD, it is ensured that the system operates in the optimal state, and the system effectively solves the problems that in traditional photovoltaic equipment networking, current signal collection precision is low, signal processing is unstable, harmonic distortion is difficult to monitor, and power quality is difficult to comprehensively evaluate. And the power output quality of the photovoltaic equipment and the reliability and economic benefits of the whole power system are remarkably improved.

Description

Technical Field

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

[0002] Photovoltaic equipment networking is to effectively manage the operation of photovoltaic power generation systems, improve energy utilization efficiency and enhance the stability of power supply systems by integrating solar panel arrays, energy storage devices, photovoltaic inverters and grid connection equipment.

[0003] At present, there are some shortcomings in the networking control of photovoltaic equipment, including insufficient power quality management and current waveform distortion. Photovoltaic systems often face harmonic distortion in the current waveform during the power generation process, which will reduce the power factor of the power grid and affect the power transmission efficiency and stability. Traditional monitoring and control methods lack real-time and accurate current waveform distortion identification and effective harmonic suppression measures, which makes the power system prone to abnormal operation 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 equipment operation. Harmonic distortion may cause equipment damage, unstable grid frequency and deterioration of power quality, which in turn affects 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 it impossible for the power system to achieve efficient and stable operation in the face of increasingly complex power demand and environmental conditions. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a photovoltaic equipment networking control method and system, which solves the problems mentioned in the background technology.

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

[0007] 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;

[0008] The digital signal processing module performs preprocessing on 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 ;

[0009] 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;

[0010] 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;

[0011] 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.

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

[0013] 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.

[0014] 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.

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

[0016] 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];

[0017] 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];

[0018] 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 .

[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 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.

[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 Then perform 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 by the following matching method:

[0026] 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;

[0027] 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.

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

[0029] 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.

[0030] Preferably,

[0031] 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.

[0032] Preferably, the power quality assessment scheme is obtained by the following assessment method:

[0033] 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;

[0034] 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.

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

[0036] 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;

[0037] Step 2: 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 ;

[0038] 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;

[0039] 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;

[0040] 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.

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

[0042] (1) When the system is running, 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 uses FFT transformation to comprehensively analyze the spectrum information. The data analysis module extracts harmonic components and calculates the total harmonic distortion rate THD, providing an accurate filter adjustment solution. The control module calculates the power factor Pf and flicker Fb, and combines THD to perform a comprehensive power quality assessment 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 to monitor harmonic distortion, and difficult to comprehensively assess power quality in traditional photovoltaic equipment networking, significantly improving the power output quality of photovoltaic equipment 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 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;

[0051] The digital signal processing module performs preprocessing on 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 ;

[0052] 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;

[0053] 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;

[0054] 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.

[0055] In this embodiment, the data acquisition module ensures high-precision current signal acquisition, and the digital signal processing module removes noise and enhances signal quality through low-pass filtering and convolution operations; the signal conversion module uses FFT transformation to comprehensively analyze the spectrum information, and the data analysis module extracts harmonic components and calculates the total harmonic distortion THD, providing an accurate filter adjustment solution; the control module calculates the power factor Pf and the flicker Fb, and performs a comprehensive power quality assessment in combination with THD to ensure that the system operates in the best state. The system effectively solves the problems of low current signal acquisition accuracy, unstable signal processing, difficult to monitor harmonic distortion, and difficult to comprehensively assess power quality in traditional photovoltaic equipment networking, and significantly improves the power output quality of photovoltaic equipment and the reliability and economic benefits of the overall power system.

[0056] Example 2

[0057] This embodiment is explained in Example 1, please refer to Figure 1 , specifically: the data acquisition module includes a current sensor unit and a data conversion integrated 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. 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.

[0059] The data conversion integrated unit converts the continuous current signal I(t) obtained by the sampling frequency Fs and the sampling point number 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 group X according to the fixed acquisition period T, wherein 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 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];

[0062] The high-frequency noise in the digital signal data set X is filtered out using the following low-pass filter formula:

[0063]

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

[0065] 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];

[0066] The following normalization formula is used to eliminate the difference in the X amplitude of the digital signal data group:

[0067]

[0068] In the formula, X norm [N] represents the normalized digital signal, X filtered [N] represents the digital signal after filtering, X min Indicates the minimum value of the digital signal after filtering, X max Indicates the maximum value of the digital signal after filtering;

[0069] 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 .

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

[0071] 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 Composed of spectrum feature vector set Fk, where

[0072] Among them, (f,p) is obtained by The formula is used for calculation, where Fs represents the sampling frequency.

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

[0074]

[0075] Wherein, |X(f,p)| represents the amplitude of the pth frequency component, specifically represents 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 represents the real 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 represents the imaginary 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, we can understand the distribution of the signal at each frequency. At the same time, the amplitude |X(f,p)| reflects the contribution of the signal at this frequency. A larger amplitude indicates that the frequency component occupies a larger proportion in the signal.

[0076] Phase Angle Obtained through the following calculation formula:

[0077]

[0078] In the formula, Represents the phase angle of the pth frequency component, specifically the phase angle of the signal at the frequency (f, p). 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], which indicates the relative position of the signal on the time axis.

[0079] In this embodiment, by using Hall effect sensors and analog-to-digital converters, high-precision, high-frequency current signal acquisition and digital signal conversion are ensured, 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 processing and convolution operations, enhances signal quality and consistency, and makes 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.

[0080] Example 3

[0081] This embodiment is explained in Example 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 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;

[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 by the following matching method:

[0085] 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;

[0086] 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.

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

[0088]

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

[0090] In this embodiment, the amplitude |X(f,p)| and phase angle 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 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.

[0091] Example 4

[0092] This embodiment is explained in Example 3, please refer to Figure 1 ,Specifically: the control module includes a calculation and fitting unit and a power quality assessment unit;

[0093] 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;

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

[0095] Pgzs=α*THD+β*Pf+χ*Fb;

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

[0097] The power factor Pf is calculated by the following formula:

[0098]

[0099] In the formula, Py represents active power, through Py = V rms *I rms*cos(θ) formula is used to calculate the value, where V rms Represents the RMS value of voltage, which is obtained by measuring and calculating the RMS value through the voltage sensor. rms represents the RMS value of the current, which is obtained by calculating the RMS value through the current sensor strategy; Sz represents the apparent power, which is obtained by Sz=V rms *I rms Formula calculation acquisition;

[0100] 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.

[0101] The control power quality assessment scheme is obtained through the following assessment methods:

[0102] 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;

[0103] 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, and the calculated compensation current I comp (t) Real-time injection into the power system to offset harmonic currents, achieve harmonic suppression and improve power quality;

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

[0105]

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

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

[0108] In this embodiment, the total harmonic distortion rate THD, the power factor Pf and the flicker amount Fb are fitted to obtain the power quality assessment index Pgzs, and matched with the preset power quality fitting assessment threshold L, to obtain the control power quality assessment scheme, to evaluate whether the power quality is qualified, and to generate a control scheme based on this, to mark the power quality as qualified or unqualified, and to iteratively adjust the total harmonic distortion rate THD and the filter until the qualified standard is met. Through precise calculation and intelligent matching, comprehensive monitoring and optimization of power quality are achieved.

[0109] Example 5

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

[0111] 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;

[0112] Step 2: 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 ;

[0113] 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 finalPerform FFT transformation to obtain spectrum information, including frequency (f, p), amplitude |X(f, p)| and phase angle Composed of spectrum feature vector set Fk;

[0114] 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;

[0115] 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.

[0116] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that 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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