415 results about "Total harmonic distortion" patented technology

The invention belongs to the technical field of power distribution network ground fault line selection, and provides a single-phase ground fault line selection method and system based on zero-sequence current mode decomposition, and the technical scheme is as follows: obtaining zero-sequence current and nth harmonic current; calculating the total harmonic distortion rate of the current according to the zero-sequence current and the nth harmonic current, and determining the maximum and minimum value of the distortion rate of the zero-sequence current; if the maximum value of the zero-sequence current distortion rate is far greater than the minimum value, the outgoing line has a fault, the zero-sequence transient current signal of each line is decomposed by using full-noise-assisted aggregation empirical mode decomposition to obtain an IMF component of each line, and the IMF component of each line is calculated; linear Gaussian fuzzy information granulation is carried out on the IMF component of each line to obtain a membership function of linear Gaussian fuzzy information particles, a fuzzy entropy is solved according to the membership function, and a single-phase earth fault line is determined according to the fuzzy entropy; if the maximum value of the zero-sequence current distortion rate is equal to the minimum value, the bus breaks down. And the fault type can be quickly and accurately judged.

The invention discloses an operation state fault monitoring method, system and device for a heavy-load overhead line, and relates to the technical field of electrical fault detection of the heavy-load overhead line. The method comprises the following steps: injecting a high-frequency test signal into a heavy-load overhead line to carry out predefined fault detection so as to obtain a total harmonic distortion rate; performing first harmonic optimization adjustment according to comparative analysis of the total harmonic distortion rate and a threshold value; performing harmonic second optimization adjustment according to the monitoring analysis result of the external load fluctuation of the heavy-load overhead line; and performing harmonic third optimization adjustment according to the monitoring analysis result of the external environment fluctuation of the heavy-load overhead line. According to the invention, through multi-stage distribution adjustment, the effect of improving the dynamic regulation and control accuracy of the high-frequency test signal injection fault monitoring method of the heavy-load overhead line in extreme weather is achieved; the problem of insufficient dynamic regulation and control accuracy of a high-frequency test signal injection fault monitoring method of a heavy-load overhead line in extreme weather exists.

The invention discloses a power grid cross-correlation harmonic suppression method, device and equipment and a storage medium, and the method comprises the steps: carrying out the wavelet packet decomposition of a subnet electric signal, and obtaining the harmonic component of a subnet at each frequency band; calculating the harmonic phase difference between the subnets according to the cross-correlation function between the harmonic components of the subnets and the topological impedance matrix, and calculating the total harmonic distortion rate according to the harmonic components of the subnets in the frequency bands; constructing a harmonic transfer equation according to the harmonic phase difference between the subnets and the equivalent output impedance of the inverter so as to calculate the harmonic responsibility proportion of the subnets; solving the double-layer game model based on the total harmonic distortion rate, the reference value of the total harmonic distortion rate and the harmonic responsibility proportion of the subnet, and obtaining the output of the governance equipment; and inputting the output of the treatment equipment into the fuzzy controller to obtain the impedance adjusting quantity of the subnet, and adjusting the virtual impedance according to the impedance adjusting quantity to update the harmonic backflow path. According to the invention, harmonic suppression among multiple subgrids during high-permeability distributed grid connection is realized, and the operation stability of the power grid is improved.

The invention discloses a three-level inverter dual-tracking model prediction control method and an inverter, and the method comprises the steps: constructing an integral sliding mode observer, and obtaining a current prediction value and a lumped disturbance estimation value through the integral sliding mode observer; calculating a voltage error of the inverter, and substituting the voltage error into the PI controller to obtain a voltage tracking control item; based on the voltage tracking control term, a switching state that minimizes the cost function is selected to control the inverter. The integral sliding mode observer is configured to calculate a current prediction error between a current prediction value of a current control period and a system output current, introduce an integrator to track the current prediction error, and generate an error function based on an output result of the integrator and the current prediction error. And feeding back a current predicted value and a lumped disturbance estimated value of the next control period through an error function. According to the invention, the method can achieve the quick estimation of the operation state of the inverter and the robust compensation of disturbance, reduces the steady-state tracking error, and reduces the total harmonic distortion of the inverter.

The invention relates to the field of electric energy quality monitoring and diagnosis, in particular to a grid-connected point electric energy quality on-line monitoring and automatic diagnosis method. The method comprises the following steps: calculating effective values and power parameters of voltage and current, extracting the amplitude and phase of each harmonic, and calculating total harmonic distortion; solving a coupling electromagnetic field equation by using an electromagnetic field coupling effect model; based on a time-space evolution model and in combination with an electromagnetic field reflection coefficient, using an anomaly detection function to locate occurrence time and position of a problem; and constructing a multi-scale electromagnetic reverse analysis model, and constructing a fault diagnosis function by combining a dynamic environment compensation model and introducing an electromagnetic field reflection coefficient and frequency deviation. According to the grid-connected point electric energy quality online monitoring and automatic diagnosis method, through integrating a time-space evolution model, a multi-scale electromagnetic reverse analysis model, an anomaly detection function and a dynamic environment compensation model, accurate control and efficient fault management of a power grid operation state are realized.

The invention relates to the technical field of power system monitoring, and provides a power grid data fault diagnosis method and device based on an intelligent power monitoring instrument, and the method comprises the steps: collecting the operation data of a power grid through the intelligent power monitoring instrument, and generating a fault feature vector containing the multi-dimensional feature parameters of voltage, current and power factor; matching and comparing the feature vector with a preset fault criterion; determining a specific fault type based on a comparison result of the characteristic parameters and a threshold value, including identifying voltage abnormity through a voltage deviation rate, identifying harmonic exceeding through a current harmonic total distortion rate, and identifying a three-phase imbalance fault through a three-phase imbalance degree; for judgment of the three-phase unbalance degree, mean square error statistic calculation is adopted, and a safety coefficient is introduced for threshold comparison; and the fault influence priority is evaluated by quantifying the degree of deviation of each characteristic parameter from the threshold. The fault diagnosis efficiency and reliability can be improved, and intelligent decision support is provided for safe operation of a power grid.

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.

The invention relates to an NILM event detection device and method based on adaptive composite sliding filtering, and the method comprises the steps: a data preprocessing module is used for calculating the instantaneous power of voltage and current data, and carrying out the noise reduction of the voltage and current data; the data judgment module generates a phase difference of voltage and current according to the voltage and current data, and judges the load type of the time period; and the event detection module is used for adaptively selecting the power threshold bilateral sliding window detection module or the total harmonic distortion bilateral sliding window detection module to detect a transient event according to a load type, and outputting a load switching interval and characteristic information thereof. According to the arrangement, noise of voltage and current data is eliminated through the data preprocessing module, signal details are reserved, meanwhile, total harmonic distortion is introduced through the bilateral sliding window detection module to serve as a second judgment basis except power, and the power load type is judged in a self-adaptive mode through complementarity information of the two dimensions of harmonic distortion degree and power. The reliability of the event detection device is improved.

The invention provides a photovoltaic DC circuit breaker fault diagnosis method and system, and relates to the technical field of fault diagnosis, and the method specifically comprises the steps: obtaining key parameters of equipment, calculating the instantaneous power, the current change rate, the temperature change rate and the energy consumption in unit time based on the key parameters, and carrying out the calculation of the instantaneous power when the instantaneous power is calculated, introducing a total harmonic distortion correction power factor; analyzing the correlation between each key index and the fault evaluation index by using a Pearson's correlation coefficient method, and calculating to obtain the fault evaluation index; and a dynamic threshold adjustment mechanism is introduced to judge whether the photovoltaic direct-current circuit breaker has a fault or not. Through a dynamic threshold adjustment mechanism and Pearson's correlation coefficient analysis, the fault diagnosis capability of the photovoltaic DC circuit breaker is improved. Compared with a traditional method, the scheme realizes high-frequency data acquisition and real-time analysis, ensures accurate evaluation of the operation state, effectively identifies potential fault risks, and reduces the probability of equipment damage.

The invention discloses a self-adaptive harmonic current suppression method for harmonic waves of a photovoltaic inverter, which belongs to the technical field of power quality control of a power system and comprises the following steps of: compensating a control strategy through a self-adaptive harmonic component of the photovoltaic inverter by adopting a'detection-reverse injection 'framework; the difference between the residual apparent capacity of the inverter after fundamental wave power supply and the borne harmonic power is used as an adaptive quantity, and the total harmonic distortion rate of the grid-connected point is reduced to the maximum extent on the premise of no overload; the method comprises the following steps: firstly, constructing a real-time harmonic detector based on a cascade generalized integrator; secondly, an inverter impedance model is established from the aspect of impedance stability, and a control parameter stability boundary is determined; then, a self-adaptive harmonic control strategy is introduced into the single-inverter grid-connected system, and a reasonable parameter setting method is provided on the basis of considering stability limitation; afterwards, a capacity-matched harmonic power distribution algorithm is provided for a multi-inverter parallel system, and the efficiency and operation stability of a photovoltaic grid-connected power generation system are improved.

The invention belongs to the technical field of new energy power generation and grid connection, and particularly relates to a wind power plant electric energy quality optimization method and system based on an improved particle swarm algorithm. Aiming at the problems of voltage fluctuation, frequency deviation and high harmonic content during grid connection of a wind power plant, a wind power plant simulation model is built through Matlab / Simulink, a multi-target fitness function is built according to the voltage deviation, the frequency deviation and the total harmonic distortion (THD), the self-adaptive inertia weight and learning factors of a particle swarm optimization algorithm are improved, and a wind power plant grid connection model is built. And dynamically adjusting voltage adjustment gain, reactive compensation amount and filter parameters. According to the embodiment, compared with a traditional method, the number of iterations is reduced by 40%, the voltage fluctuation suppression ratio is improved by 10%, the frequency adjusting time is shortened to be within 0.3 second, the THD is reduced to 2.1% from 5.2%, and the power grid stability and the electric energy quality are improved.

The invention discloses a dynamic load regulation-based DC charging pile power optimization device and optimization method, and relates to the technical field of artificial intelligence, and the method comprises the steps: obtaining electric energy quality data through extracting a voltage deviation and a total harmonic distortion rate, outputting a prediction value of the electric energy quality data through an electric energy quality prediction model, and calculating a deviation rate; constructing a regional charging network, inputting the regional charging network into the multilayer graph attention network, and outputting a regional electric energy quality evaluation value; a time dimension weight vector is calculated based on the deviation rate, a space dimension weight vector is calculated based on the regional power quality evaluation value, an adaptive weight vector is calculated according to the time dimension weight vector and the space dimension weight vector, a reinforcement learning model is constructed, and an optimal strategy is obtained; the optimal strategy is executed, the actual charging power and the actual charging time period are collected, the total charging amount, the total charging demand, the charging demand response rate and the charging expenditure are calculated and fed back to the reinforcement learning model, the reinforcement learning model is continuously optimized, and the electric energy quality is improved.

The invention provides an implementation method of a novel low-distortion digital modulation direct drive power amplifier device, and relates to the field of plasma generation radio frequency power supplies, the method realizes acquisition of modulation waveform signals through a delta-sigma oversampling technology, and realizes further improvement of the sampling rate of the modulation waveform signals through a PDM pulse distribution unit interpolation filter. The exciter can generate multi-phase PDM modulation waveform pulses and carrier wave driving pulses, and directly drives the power amplifier module to complete carrier wave generation and waveform modulation. Multi-phase PDM modulation can achieve a better modulation waveform THD (Total Harmonic Distortion) index, it is ensured that a modulation waveform signal is basically subjected to distortion-free recovery, but in order to reduce the complexity of a system and give consideration to the modulation waveform total harmonic distortion index, the multi-phase PDM modulation is generally controlled within 12 phases. In addition, a modulation waveform signal is divided into a plurality of equal-amplitude PDM square wave signals by a multi-phase PDM modulation and superposition technology, so that the power amplifier works in an on-off state, and the efficiency of the power amplifier is improved.

The invention discloses an electric energy meter abnormal phenomenon automatic detection and identification method and system, and relates to electric digital data processing, and the method comprises the steps: carrying out the digital signal processing of initial data, the voltage effective value, the total harmonic distortion rate and the analysis of communication message abnormal codes, and generating a structured feature matrix; on the basis of the structured feature matrix, threshold comparison, composite condition judgment and continuous anomaly detection are executed through multi-level rule triggering, and an anomaly event report is generated; comparing the abnormal event report with a historical case, obtaining the similarity between the current abnormal event report and the historical case, and obtaining a similarity TOP-N case set; generating an anomaly diagnosis report by using weighted evidence fusion in combination with rule triggering intensity quantification and case matching credibility conversion; and updating the case library according to the abnormality diagnosis report, and counting and adjusting a rule threshold based on a sliding window. According to the method, the abnormal judgment threshold values of key parameters such as voltage and harmonic waves can be adjusted in real time through dynamic threshold value optimization, and the adaptability is improved.

The embodiment of the invention provides an excitation signal generation method and system and a digital eddy current sensor, and the method comprises the steps: outputting a square wave signal through a pulse width modulation assembly of a microcontroller unit, and enabling the frequency and resolution of the square wave signal to be adaptive to eddy current probes with different inductance values; inputting the square wave signal into a low-pass filter for filtering, and setting the cut-off frequency of the low-pass filter, the suppression times of higher harmonics and the attenuation slope so as to output a sine wave signal with a target total harmonic distortion range; the amplitude of the sine wave signal is collected in real time, and the pulse width modulation duty ratio and the passband gain of a low-pass filter are dynamically adjusted in combination with a digital control algorithm, so that the sine wave signal is subjected to self-adaptive adjustment and correction and is output; and taking the sine wave signal as an excitation source of an eddy current probe, and driving the eddy current probe to carry out nondestructive testing. According to the invention, the excitation signal which gives consideration to high-frequency signal generation, deep harmonic suppression and digital adaptive adjustment can be generated.

The invention relates to the technical field of electric power system control, and discloses an electric power system arc harmonic collaborative suppression and intelligent closed-loop control system, which comprises the steps of: acquiring sensor data and uploading the sensor data to an edge computing unit by deploying a sensor; wavelet threshold denoising and electromagnetic interference compensation are adopted; the method comprises the following steps: constructing a coupling model containing arc plasma dynamic resistance, optimizing VMD parameters through PSO, extracting a joint feature vector, filling an arc and harmonic dynamic coupling analysis gap, calculating a total harmonic distortion rate and arc extinction time in combination with a power grid damping ratio, solving an optimal SVG trigger angle, and solving the problem of lack of power grid stability evaluation; correcting the opening time of the circuit breaker, calculating the error of the total harmonic distortion rate and the error of the arc extinction time, and adjusting the SVG trigger angle; calculating the precision of the evaluation model, calculating the full life cycle through the aging coefficient, analyzing and judging whether an early warning signal is generated or not, and triggering equipment replacement early warning based on the generated early warning signal.

The invention provides a single-phase four-quadrant rectifier IGBT open-circuit fault diagnosis method under multiple working conditions, and relates to the technical field of IGBT fault diagnosis. Historical data of alternating current side voltage, alternating current side current and direct current side voltage of the single-phase four-quadrant rectifier are obtained, and a total harmonic distortion rate threshold value, a direct current side voltage threshold value and an alternating current side current first threshold value are obtained. And constructing and training an IGBT open-circuit fault positioning identification model. Detecting the total harmonic distortion rate of the alternating-current side current of the single-phase four-quadrant rectifier in real time, if the total harmonic distortion rate exceeds a threshold value, entering fault positioning, collecting and calculating the average value of the direct-current side voltage and the alternating-current side current in the period, and judging the fault of the single-phase four-quadrant rectifier under the specific working condition according to the comparison of the average value and the threshold value. Or using an IGBT open-circuit fault positioning identification model to diagnose the fault; if the threshold value is not exceeded, the next period is continuously monitored. According to the invention, the IGBT fault diagnosis efficiency and accuracy of the single-phase four-quadrant rectifier are improved.

The embodiment of the invention discloses a collaborative optimization method and device for the power quality of a high-permeability transformer area. The method comprises the following steps: acquiring three-phase voltage, three-phase current and environment temperature data; the voltage deviation, the three-phase unbalance degree, the total harmonic distortion rate and the reactive vacancy of the high-permeability transformer area are calculated based on the three-phase voltage and the three-phase current; taking voltage deviation as a primary optimization target, considering optimization of three-phase unbalance degree, total harmonic distortion rate and reactive vacancy, constructing a multi-target optimization function, and carrying out dynamic constraint on an optimization process based on environment temperature data; solving the multi-objective optimization function by adopting an optimization algorithm to obtain a group of optimal decision variables, and converting the decision variables into corresponding control instruction sets; and the control instruction set is issued to the on-load voltage regulating transformer, the reactive compensation equipment and the power electronic compensation module for execution. Therefore, the problems of voltage out-of-limit, harmonic pollution and imbalance are effectively solved through a multi-target cooperation and temperature self-adaption mechanism.

The invention provides a control circuit for a PFC (power factor correction) circuit and a THD (total harmonic distortion) optimization method of the control circuit. The control circuit comprises an input voltage amplitude judgment circuit which is used for obtaining an input voltage amplitude judgment signal used for judging the amplitude of the input voltage of the input end of the PFC circuit; the maximum conduction time control circuit is used for controlling the maximum conduction time of the main power switch tube based on the input voltage amplitude judgment signal, when the input voltage amplitude is a first voltage, the maximum conduction time is a first time, when the input voltage amplitude is a second voltage, the maximum conduction time is a second time, the first voltage is greater than the second voltage, and the second voltage is greater than the first time. The first time is shorter than the second time. According to the control circuit for the PFC circuit and the THD optimization method of the control circuit, the THD performance can be obviously improved by reducing the maximum conduction time in a high input voltage amplitude state.

The invention discloses a power distribution network harmonic suppression method and system, and the method comprises the steps: building an objective function with the minimum total harmonic distortion rate of nodes of a whole network, building a power flow constraint, a harmonic distortion rate constraint and an active filter device related constraint, and obtaining a power distribution network harmonic suppression model according to the objective function and constraint conditions. A distributed partially observable Markov decision process is established based on the MADDPG algorithm, and harmonic suppression is performed on the power distribution network based on the distributed partially observable Markov decision process by using the PRE-combined MADDPG algorithm, so that the problem of low sample efficiency of a reinforcement learning algorithm is effectively solved, the stability of a training process and the convergence speed of the algorithm are promoted, and the robustness of the power distribution network is improved. According to the method, the effectiveness of the finally obtained harmonic suppression strategy is ensured, based on a centralized training-distributed execution architecture, it can be ensured that a plurality of active filter devices can make a cooperative control strategy giving consideration to the harmonic problem of the whole power distribution network in real time only by means of distributed observation, and therefore efficient whole network harmonic cooperative governance is achieved.

The invention discloses a real-time noise reduction method and system supporting Bluetooth audio interaction, and the method comprises the steps: collecting an environment audio signal and a Bluetooth interaction audio signal, and carrying out the timestamp alignment and spatial calibration of the environment audio signal and the Bluetooth interaction audio signal; an improved multivariate variational mode decomposition algorithm is adopted to decompose and extract noise features, the noise features are combined with user historical noise data, a dynamic noise model is constructed through a long-short-term memory network, parameters are updated in real time, Bluetooth interaction audio content features and a user behavior data recognition scene are analyzed, and a noise reduction strategy is determined. And according to the dynamic noise model and the scene result, reinforcing learning to optimize filter parameters, generating a directional anti-noise signal to carry out noise reduction on the Bluetooth interaction audio signal, collecting the noise reduction intensity manually adjusted by a user, calculating voice definition and total harmonic distortion, and carrying out noise reduction on the Bluetooth interaction audio signal. And inputting a feedback and evaluation result into the modeling and noise reduction steps, carrying out dynamic range adjustment, sound channel balance and power amplification on the audio after noise reduction, and outputting the audio through a loudspeaker.

The application discloses a kind of water electrolysis hydrogen production rectifier transformer harmonic active inhibition optimization method, comprising the following steps: constructing rectifier circuit, rectifier circuit includes switch tube, the voltage vector and zero vector of switch tube output are combined, and combined output voltage vector is obtained;The harmonic amplitude is obtained by processing combined output voltage vector, Levy tangent flight strategy and confidence domain variation strategy are introduced in black-winged kite optimization algorithm to construct improved dynamic search algorithm, the total harmonic distortion is obtained by iterative calculation of harmonic amplitude by improved dynamic search algorithm, i.e. optimal switch tube combination, the switch tube of rectifier circuit is adjusted by optimal switch tube combination, and the total harmonic distortion of rectifier circuit is reduced.The optimal switch tube combination of rectifier circuit is iteratively calculated by improved dynamic search algorithm in the application, effectively reduces resource consumption, and processing speed is accelerated, and the efficiency and accuracy of electrolytic water hydrogen production rectifier are improved.

The invention relates to the technical field of supervision control, in particular to a new energy storage optimization control method and system, and the method comprises the following steps: collecting a grid-connected point voltage amplitude deviation, a frequency deviation and a voltage total harmonic distortion rate, and generating a power grid stress index; according to the method, the multi-dimensional state vector is constructed by collecting the grid-connected point voltage amplitude deviation, the frequency deviation and the total harmonic distortion rate to generate the stress index reflecting the power grid operation pressure, accurate quantitative sensing of the power grid state is achieved, the power grid supporting gain coefficient is dynamically generated according to comparison of the index and the preset threshold value, and the power grid supporting effect is improved. And the total required power to be responded by the energy storage system is adjusted and determined, so that the power support strength is matched with the actual demand of the power grid, and insufficient response or excessive response is avoided.

The invention discloses a three-phase uninterruptible power supply device and a control method thereof. The control method comprises the following steps: acquiring an input current of a three-phase alternating current power supply and a load voltage and a load current of an output end of an inverter circuit; carrying out harmonic separation on the collected input current, and determining a total harmonic distortion rate; when the total harmonic distortion rate is greater than a preset total harmonic distortion rate threshold value, generating a harmonic compensation signal; calculating load variation and voltage deviation based on load voltage and load current, dynamically adjusting proportional gain and integral time in real time, and generating a fundamental voltage control signal; superposing the fundamental wave voltage control signal and the harmonic compensation signal to generate a preliminary modulation wave; dynamically adjusting the dead zone time of the PWM wave, and combining the dead zone time with the preliminary modulation wave to generate the PWM wave; according to the control method, the three-phase alternating current is converted into the alternating current meeting the load requirement through the PWM waves, the response capacity to voltage sag, voltage fluctuation and harmonic disturbance is improved, and the output electric energy quality is improved.

The invention belongs to the technical field of power electronics, and relates to a hybrid device common bridge arm three-level split output inverter modulation method and system, and the method comprises the steps: obtaining a mapping phase angle, a modulation degree and a region number according to a reference voltage vector generated by a three-phase original modulation wave; mapping the phase angle, the modulation degree and the switching period according to the size of the modulation degree to obtain two kinds of vector action time; generating two modulation waves according to the area number and the action time of the two vectors; generating a first pulse driving signal according to the area number, the first modulation wave and the forward and reverse carrier waves; generating a final carrier according to the area number and the forward and reverse carriers, and generating a second pulse driving signal according to the second modulated wave, the forward carrier, the forward carrier of the previous period and the final carrier; and selecting a driving signal from the two pulse driving signals according to the area number. The modulation degree can be maximized, driving pulses are respectively generated in different modulation degree ranges, the output current quality is high, and the total harmonic distortion rate is low.

The present application discloses a method, apparatus, device and storage medium for cross-correlated harmonic control in power grids. The method includes: performing wavelet packet decomposition on subnet electrical signals to obtain the harmonic components of the subnet in each frequency band; calculating the harmonic phase difference between subnets based on the cross-correlation function and topological impedance matrix between the harmonic components of each subnet, and calculating the total harmonic distortion rate based on the harmonic components of the subnet in each frequency band; constructing a harmonic transfer equation based on the harmonic phase difference between subnets and the equivalent output impedance of the inverter to calculate the harmonic responsibility ratio of the subnet; solving a two-layer game model based on the total harmonic distortion rate and its reference value and the harmonic responsibility ratio of the subnet to obtain the output of the control equipment; inputting the output of the control equipment into the fuzzy controller to obtain the impedance adjustment amount of the subnet, and adjusting the virtual impedance according to the impedance adjustment amount to update the harmonic return path. The present application realizes the harmonic control between multiple subnets during high-penetration distributed grid connection, thereby improving the stability of power grid operation.

The invention discloses a power distribution control method and device for a photovoltaic hybrid energy storage direct current microgrid based on fuzzy second-order high-pass filtering, and the method comprises the steps: researching the topological structure and working principle of the photovoltaic hybrid energy storage direct current microgrid and the energy management of the microgrid, and obtaining a power balance relation of the direct current microgrid; a comprehensive operation control strategy of the micro-grid is established, and it is determined that a photovoltaic power generation unit adopts maximum power point tracking control of fuzzy control, a grid-connected inverter adopts double closed-loop control of a voltage outer loop and a current inner loop, and a hybrid energy storage unit adopts fuzzy second-order high-pass filtering algorithm control; frequency division distribution and stability of a traditional second-order high-pass filter are studied, so that the second-order high-pass filter based on fuzzy logic is further studied, the SOC of the super capacitor is determined as a control index, and a fuzzy rule of a filtering time constant is adaptively adjusted; the established fuzzy logic variable time constant second-order high-pass filtering control simulates and compares the hybrid energy storage system power, the DC bus voltage and the super capacitor SOC under the variable illumination and load conditions with the fixed constant second-order high-pass filtering control, and compares the change curves of the super capacitor SOC of two strategies under the condition of changing the initial SOC value of the super capacitor. Three-phase current and current total harmonic distortion of the two strategies are compared, and it is verified that the efficiency of a photovoltaic power generation system is improved under the strategies, the SOC of a super capacitor changes within a reasonable range, a micro-grid can stably operate in a grid-connected mode, and grid-connected current harmonic distortion is effectively reduced.

The invention discloses an electric energy quality comprehensive monitoring method and system based on real-time waveform analysis. The method comprises the following steps: S1, acquiring an analog voltage signal acquired by a mutual inductor; s2, preprocessing to obtain a voltage waveform data segment; s3, performing multi-dimensional feature extraction to obtain a voltage waveform multi-dimensional feature vector; s4, extracting a voltage RMS effective value, a total harmonic distortion rate and wavelet packet energy; s5, inputting the voltage RMS effective value, the total harmonic distortion rate and the wavelet packet energy into a grading event pre-detection model to obtain an event feature subset coding vector; and S6, enabling the event feature subset coding vector to pass through an intelligent event fine classification model to obtain an electric energy event accurate classification result. According to the electric energy quality comprehensive monitoring method and system based on real-time waveform analysis disclosed by the invention, the accuracy and efficiency of electric energy quality event monitoring are greatly improved.

The invention discloses a multivariable model predictive control method for a photovoltaic inverter grid-connected system, which comprises the following steps of: establishing a mathematical model of an inverter under a rotating coordinate system, and setting a discrete mathematical model on the basis of traditional model predictive control to obtain a predictive value of output current; and taking the predicted value, the current error at the sampling moment and the error of the direct current bus voltage as control factors of the value function, and seeking the minimum solution of the value function to achieve the optimal control effect. According to the multivariable model predictive control method for the photovoltaic inverter grid-connected system, through the steps, the photovoltaic grid-connected response efficiency can be improved, the total harmonic distortion rate can be reduced, the stability and the anti-interference performance of the direct-current bus voltage can be enhanced, the grid-side current can be controlled at a lower total harmonic distortion level, and the effect is obvious.

The invention discloses an ultra-high heart rate electrocardio acquisition system, which comprises a signal acquisition unit adopting an ADS131E08 chip and supporting 8 channels, a 24-bit delta-sigma ADC (Analog to Digital Converter) and programmable gain amplification; the dynamic sampling rate adjusting unit is used for dynamically adjusting the sampling rate between 1kSPS and 64kSPS according to the heart rate change, and the sampling rate is increased to be greater than or equal to 2kSPS when the heart rate exceeds 200 times per minute; a low-noise design circuit has a common-mode rejection ratio greater than or equal to 110dB, a dynamic range greater than or equal to 118dB and total harmonic distortion less than or equal to-90dB, and power frequency interference is suppressed; the morphological enhancement module is used for enhancing QRS wave group characteristics by using digital morphological filtering; the multi-lead fusion module is used for fusing multi-lead signals through time sequence alignment and R-wave phase difference analysis; and the anti-interference module is integrated with a hardware comparator, and is used for lead falling detection and dynamic digital notch filtering. The system is suitable for researches on myocardial ischemia, arrhythmia and drug cardiotoxicity. Compared with the prior art, the device has the advantages of being simple in structure, low in cost, high in precision, high in reliability and the like, and can effectively solve the problem of animal ultrahigh heart rate electrocardio collection.