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322 results about "Frequency meter" patented technology
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A frequency meter is an instrument that displays the frequency of a periodic electrical signal. Various types of frequency meters are used. Many are instruments of the deflection type, ordinarily used for measuring low frequencies but capable of being used for frequencies as high as 900 Hz. These operate by balancing two opposing forces. Changes in the frequency to be measured cause a change in this balance that can be measured by the deflection of a pointer on a scale. Deflection-type meters are of two types, electrically resonant circuits and ratiometers.
Adaptive fault reflection method based on adjustable excitation frequency
PendingCN121596031AFault location by conductor typesFault location by pulse reflection methodsAdaptive optimizationImpedance matching
The invention discloses a self-adaptive fault reflection method and device based on adjustable excitation frequency, and belongs to the technical field of cable fault detection and positioning. The method comprises the following steps: injecting an excitation signal which can be adjusted in a range of 1kHz-10MHz through an adjustable impedance matching network; collecting a reflected signal and calculating an SNR (f) curve; optimizing by adopting a particle swarm optimization algorithm and taking maximization of a signal-to-noise ratio as a target, and determining an optimal excitation frequency; and finally, calculating the fault position and type based on the optimal frequency. The particle swarm optimization algorithm is adopted to perform adaptive optimization on the excitation frequency, and the adjustable impedance matching network is combined to form a closed-loop adaptive detection framework of excitation-acquisition-analysis-optimization-re-excitation, so that the excitation frequency can be automatically adjusted according to a real-time detection result, and the detection accuracy is improved. And the fault detection sensitivity, the positioning precision and the energy efficiency are obviously improved.
Owner:CHONGQING UNIV OF POSTS & TELECOMM
Power grid equipment frequency adaptive resampling method based on dynamic scale factor
The invention belongs to the field of power distribution automation, and relates to a power grid equipment frequency adaptive resampling method based on a dynamic scale factor, and the method comprises the steps: carrying out the point compensation through employing a linear interpolation method when a power grid equipment detects that the number of continuous lost points is smaller than or equal to 3; selecting a voltage signal channel or a current signal channel to carry out zero crossing point detection and real-time frequency calculation; when the real-time frequency obtained through calculation deviates from the nominal frequency, the power grid equipment introduces a dynamic scale factor for resampling, sampling points are increased when the real-time frequency is higher than the nominal frequency, and sampling points are reduced when the real-time frequency is lower than the nominal frequency; writing data obtained by resampling into a calculation annular cache region of the power grid equipment; and performing FFT calculation on the data in the calculation annular cache region to obtain power grid parameters. The sampling interval of the data acquisition unit is dynamically adjusted by increasing or reducing the sampling points, so that the sampling time sequence and the actual signal period are synchronized, the sampling frequency and the real-time frequency are adaptively matched, and the sampling distortion problem under the power grid frequency fluctuation is solved.
Owner:SHANDONG ELECTRIC HIMILE ENERGY SAVING TECH CO LTD
Integer frequency signal generation circuit and generation method of microprocessor
The invention relates to the field of pulse signal generation, and discloses an integer frequency signal generation circuit and method for a microprocessor, and the circuit comprises a flipping register, a frequency division register, a counter, a frequency signal flipping module, an integer frequency calculation unit, and a time delay unit. The integer frequency calculation unit is used for calculating the delay series of the fractional part of the frequency division value when the enable signal 1 is valid, and sending the delay series to the delay unit; and the delay unit is used for carrying out delay less than one clock period on the frequency signal output by the frequency signal overturning module according to the delay series sent by the integer frequency calculation unit, and outputting an integer frequency signal. According to the integer frequency signal output circuit disclosed by the invention, the frequency division value and the delay series of the frequency division register are automatically changed through the integer calculation module and the delay series calculation module, and the delay series controls the one-out-of-256 selector to be used for selecting the frequency signal output of the corresponding delay module in the delay unit, so that the generation of the integer frequency signal is realized.
Owner:青岛本原微电子有限公司
Method and system for detecting anti-seismic property of fabricated steel-wood composite structure
ActiveCN121298163AAnalysing solids using sonic/ultrasonic/infrasonic wavesMaterial analysis using acoustic emission techniquesInterface wavesGeophysics
The invention relates to the technical field of anti-seismic performance detection, in particular to an anti-seismic performance detection method and system for an assembled steel-wood composite structure, and the method comprises the steps: arranging a multidirectional acoustic emission sensor in a steel-wood structure node area, applying simulated seismic vibration, and synchronously collecting acoustic emission signals; the method comprises the following steps: preprocessing collected acoustic emission signals, dividing the acoustic emission signals into signals corresponding to microcracks and contact slippage, respectively calculating an energy attenuation rate and a phase offset, and constructing a matrix; micro-impact is applied to the steel-wood node through an electromagnetic excitation device, a response signal is collected, resonant frequency is extracted, the drift distance between the resonant frequency and a reference value is calculated, and the severity of interface damage is determined according to the value of the drift distance; the damage correlation index calculation takes the characteristic value of the interface wave propagation characteristic matrix and the resonance frequency drift distance as input, the damage correlation index is calculated through the correlation coefficient, and the damage grade is divided according to the correlation coefficient. And differential characterization of different damage types is realized through the interface wave propagation characteristic matrix.
Owner:CHINA RAILWAY INVESTMENT GRP CO LTD +2
Fan frequency control method and device, electronic equipment and computer storage medium
The invention discloses a fan frequency control method and device, electronic equipment and a computer medium, and belongs to the technical field of automatic incineration. According to the specific scheme, the method comprises the steps of obtaining a parameter sequence value of a control parameter of the automatic combustion control system in a historical period, a current flow value of main steam flow, a flow set value of the main steam flow, a real-time value of steam pocket pressure, a hearth material layer pressure difference value and a control variable sequence value in the historical period; calculating a flow predicted value of the main steam flow; calculating flow deviation; calculating the frequency of an intermediate fan; the steam drum fan frequency is calculated; the flow fan frequency is obtained; calculating a primary frequency given value; and the primary frequency set value is dynamically corrected, and the target primary fan frequency of the primary fan is obtained and adopted to control the primary fan. The response speed of the automatic combustion control system can be effectively improved, so that the control of the frequency of the extension set can be closer to the actual production condition.
Owner:CHINA NAT ENVIRONMENTAL PROTECTION CORP +1
Transformer winding fault detection method and system based on frequency response and medium
The embodiment of the invention relates to the technical field of transformer fault detection, and discloses a transformer winding fault detection method and system based on frequency response and a medium, and the method comprises the steps: determining the equivalent inductance and equivalent capacitance of a transformer winding; and calculating a first-order grounding coefficient of driving point admittance by using the peak frequency and the valley frequency when the neutral point is grounded, and calculating a first-order open-circuit coefficient by using the peak frequency and the valley frequency when the neutral point is open-circuit. A first difference function is constructed through the equivalent inductance, the scaling rate and the first-order grounding coefficient, and a second difference function is constructed through the equivalent capacitance and the first-order open circuit coefficient. And fault detection of the transformer winding is carried out according to a comparison condition between fluctuation of the first difference function and the second difference function and a preset threshold value, and early sensitive detection is realized.
Owner:YUNNAN POWER GRID CO LTD +1
Short bolt axial stress detection method and device based on electromagnetic ultrasonic resonance
PendingCN120927181AMachine part testingMeasurement of torque/twisting force while tighteningUltrasonic sensorTransducer
The invention provides a short bolt axial stress detection method and device based on electromagnetic ultrasonic resonance, and relates to the technical field of industrial fastener stress detection. The method comprises the following steps: determining a preset period and frequency of an excitation signal according to material characteristics of a to-be-measured short bolt, and calibrating resonant frequency and stress to obtain a calibration curve; classifying the lengths of the short bolts to be measured to obtain bolts with known original lengths and in-service bolts with unknown original lengths; based on the determined preset period and frequency, first-order resonant frequency corresponding to the bolt with the known original length is obtained through an electromagnetic ultrasonic transducer and a single-wave resonance method; based on the determined preset period and frequency, first-order resonant frequency corresponding to the in-service bolt with the unknown original length is obtained through an electromagnetic ultrasonic transducer and a double-wave resonance method; and calculating the axial stress of the corresponding short bolt to be measured according to the calibration curve and the first-order resonant frequency. The problems that in the prior art, the energy conversion efficiency is low, and the short bolt detection effect is poor are solved.
Owner:BEIHANG UNIV
Photovoltaic support displacement safety monitoring method, system and equipment
PendingCN121163448AHeight/levelling measurementPhotovoltaic energy generationData acquisitionEarly warning signs
The invention relates to the technical field of photovoltaic support monitoring, and discloses a photovoltaic support displacement safety monitoring method. The method comprises the steps that sensors are installed at different nodes of a photovoltaic support based on a stay wire displacement monitoring system, and horizontal displacement and vertical displacement are collected in real time; correcting the displacement data through multi-dimensional data fusion in combination with environmental factors; and calculating the vibration frequency of the bracket, monitoring the frequency change in real time, and generating a bracket health assessment report and an early warning signal. In the prior art, accurate monitoring of support displacement is difficult to realize under a complex environment condition, and especially under the condition of non-uniform support stress or foundation settlement, accurate displacement monitoring and early warning cannot be provided. According to the invention, through multi-node sensor data acquisition, environmental factor correction and dynamic vibration frequency calculation, accurate monitoring and early warning of the displacement of the photovoltaic support are realized, and the operation safety and reliability of a photovoltaic system are improved.
Owner:CHN ENERGY NEW ENERGY TECHNOLOGY RESEARCH INSTITUTE CO LTD
Ship signal adaptive time-frequency analysis method based on instantaneous frequency direction self-adjustment
The invention discloses a ship signal adaptive time-frequency analysis method based on instantaneous frequency direction self-adjustment. The ship signal adaptive time-frequency analysis method comprises the steps of collecting ship signals to be subjected to time-frequency analysis and performing short-time Fourier transform; estimating the instantaneous frequency of the ship signal based on short-time Fourier transform time-frequency distribution in combination with time-frequency narrow-band features; calculating the instantaneous frequency and the optimal window length after smoothing; segmenting the smoothed instantaneous frequency in time, calculating time-frequency domain direction pre-guidance of each time period, and constructing a Chirp atomic direction over-complete dictionary; segmenting the ship signal in time, and calculating the matching direction of the ship signal in each time period so as to calculate and improve Chirplet transformation time-frequency distribution; and calculating the optimal short-time Fourier transform in combination with the optimal window length, and correcting and improving Chirplet transform time-frequency distribution. According to the method, the robustness of short-time Fourier transform and the anisotropy of improved Chirplet transform are utilized at the same time, and time-frequency distribution with high robustness and high time-frequency resolution is obtained.
Owner:南京畅淼科技有限责任公司
Square wave generation method and system based on DDS signal transmitter
PendingCN121578858AElectric pulse generator circuitsGenerating/distributing signalsSquare waveformFrequency meter
The invention relates to a square wave generation method and system based on a DDS signal transmitter, and belongs to the technical field of digital electronic signal synthesis. The method comprises the following steps: calculating a digital analog signal sampling frequency based on a square wave output frequency set by a user, and obtaining a digital fundamental frequency phase signal according to a phase-locked loop precision range; mapping the digital fundamental frequency phase signal into a sinusoidal amplitude signal according to a digital phase accumulation mechanism to obtain a digital-analog conversion clock, binarizing the sinusoidal amplitude signal, and outputting a square wave output period; dividing a square wave output period into a low level region and a high level region according to the precision range of the phase-locked loop, reading a square wave output frequency set by a user through a random storage address, and outputting a non-offset phase-locked square wave; and constructing an error accumulation self-checking architecture to calculate a frequency control word, and when detecting that the frequency control word has a decimal discarding error, recalculating the frequency control word.
Owner:GUANGZHOU XINGYI ELECTRONICS TECH CO LTD
Capacitance monitoring method and system based on frequency sweep resonance point
ActiveCN121559167ACapacitance measurementsElectrical measurement instrument detailsCapacitanceImpedance response
The invention relates to the technical field of electronic measurement and sensing, and discloses a capacitance monitoring method and system based on a sweep frequency resonance point, and the method comprises the steps: carrying out the coarse sweeping in an initial frequency range, obtaining an impedance spectrum, and recognizing a coarse resonance interval; carrying out fine scanning in the interval and calculating an accurate resonant frequency by adopting a quadratic interpolation method; calculating a capacitance value in combination with the mapping table; and dynamically adjusting the frequency sweeping window of the next period based on the historical resonant frequency. The system comprises an excitation signal generation unit, an impedance response acquisition unit, a coarse / fine scanning control unit, a resonant frequency calculation unit, a capacitance resolving unit and a dynamic frequency window updating unit, and integrates a temperature compensation and anomaly detection mechanism. Through the two-stage frequency sweeping and self-adaptive frequency window strategy, the monitoring period is shortened to 1 / 5 or below of that of a traditional method while it is guaranteed that the resonant frequency measurement precision is superior to 0.01 Hz, and the real-time performance, stability and environmental adaptability are remarkably improved.
Owner:CHANGCHUN POWER SUPPLY OF JILIN POWER
Frequency measurement method, system and device and computer readable storage medium
PendingCN120539483AFrequency to amplitude conversionFrequency to phase shift conversionFrequency measurementsSimulation
The invention discloses a frequency measurement method, system and device and a computer readable storage medium, and belongs to the technical field of electricians. Acquiring a sampling value, and judging whether the sampling value is invalid or not based on the absolute value of the sampling value; determining a first frequency value based on the sampling value and the sampling frequency; determining an amplitude and a phase of a vector value of the signal based on the sampling value; determining a second frequency value according to the phase change; determining a frequency based on the first frequency value and the second frequency value; according to the frequency measurement method, system and device and the computer readable storage medium, a low-value locking technology, an extreme value anti-shake technology, a sampling zero crossing point anti-shake technology and a hysteresis frequency calculation technology are adopted, and sampling point frequency measurement and vector frequency measurement are organically combined, so that the frequency measurement precision when the signal frequency fluctuates in a large range under different working conditions is ensured; and the problem that the frequency measurement error is large when the signal frequency fluctuates in a large range is solved.
Owner:NANJING GUODIAN NANZI WEIMEIDE AUTOMATION CO LTD
Sampling signal compensation method of power converter and power conversion device
The invention provides a sampling signal compensation method of a power supply converter and a power supply conversion device. The sampling signal compensation method comprises the following steps: S1, acquiring a sampling signal from the power supply converter; s2, obtaining the frequency of the sampling signal; s3, a compensation parameter calling index number is obtained through calculation according to the frequency of the sampling signal, a pre-stored compensation parameter table is inquired according to the compensation parameter calling index number, and a discrete compensation parameter table is obtained; s4, the sampling signal is compensated through the discrete compensation parameter table, a feedback signal is obtained, and the compensation parameter table is a discrete corresponding data table of time and compensation amount obtained at the lowest frequency of the sampled signal.
Owner:GREAT WALL POWER SUPPLY TECH CO LTD
Cable aging degree judgment method based on impedance spectrum and related device
ActiveCN121231958ATesting dielectric strengthComplex mathematical operationsDielectric lossFrequency meter
The invention belongs to the technical field of cable insulation material aging detection, and relates to a cable aging degree judgment method based on an impedance spectrum and a related device. The method comprises the steps of obtaining a reflection coefficient curve based on an impedance spectrum curve; obtaining a reflection coefficient real part curve based on the reflection coefficient curve, and extracting a resonant frequency corresponding to a resonant point of the reflection coefficient real part curve; calculating a relative dielectric constant real part of an insulating medium of the cable to be measured under different resonant frequencies; outputting an attenuation constant curve based on the reflection coefficient curve and a cable reflection coefficient amplitude calculation model; extracting a plurality of attenuation constant values of the attenuation constant curve on the resonant frequency; substituting the attenuation constant value and the relative dielectric constant real part into a dielectric loss angle tangent value calculation model to obtain a dielectric loss angle tangent value of the to-be-measured cable under the resonant frequency; and carrying out aging degree judgment based on the dielectric loss angle tangent value. The problem that an existing method is long in time consumption or cannot acquire full-band dielectric information of a cable insulating material is solved.
Owner:XI AN JIAOTONG UNIV +2
Transformer operation state monitoring and fault early warning method based on state index calculation
The application discloses a transformer operation state monitoring and fault early warning method based on state index calculation, relates to the technical field of transformer operation state monitoring, and aims to solve the problem of reduced accuracy of potential fault identification. In the transformer operation process, winding temperature is collected to calculate temperature rise trend and monitor vibration state, vibration frequency is obtained, operation stress coefficient is calculated in combination with the temperature rise trend and the vibration frequency, the electric conductivity of insulation oil in the oil circulation pipeline is detected, the state index is generated by comprehensively considering the electric conductivity and the operation stress coefficient, and the transformer operation state is classified accordingly. When the state is warning, multiple groups of different cooling powers are inputted, the monitoring time is set, the corresponding radiator outlet air temperature is collected, the power change amount and the outlet air temperature difference change amount are calculated after the cooling powers are sorted, the heat dissipation characteristics are comprehensively evaluated, and it is judged whether a fault warning signal is generated, so that early warning of potential faults of the transformer is realized, and operation safety and reliability are improved.
Owner:GUANGXI POWER GRID CO LTD NANNING POWER SUPPLY BUREAU +1
Insulation monitoring evaluation method and device for high-voltage direct-current system cable, electronic equipment and storage medium
The invention provides an insulation monitoring evaluation method and device for a high-voltage direct-current system cable, electronic equipment and a storage medium, and relates to the technical field of cable insulation monitoring, and the method comprises the steps: obtaining the initial resonant frequency of the high-voltage direct-current system cable in an initial operation state, estimating the target real-time resonant frequency of the high-voltage direct-current system cable after the operation target period; calculating a difference value between the initial resonant frequency and the target real-time resonant frequency to obtain a target resonant frequency offset; based on the target resonant frequency offset and a preset proportionality coefficient, a target cable aging state quantity is calculated and obtained, the target cable aging state quantity is compared with a preset threshold value, and the aging condition of the cable is evaluated according to a comparison result; wherein the preset proportionality coefficient is calculated by fitting the linear relation between the resonant frequency offset and the aging degree in the cable models of different aging degrees. Through the method provided by the invention, online monitoring and real-time evaluation of the health state of the cable are realized.
Owner:TSINGHUA UNIVERSITY
Dynamic phase compensation method based on double DDS modules
The invention provides a dynamic phase compensation method based on double DDS modules, and belongs to the technical field of digital frequency synthesis. The invention provides the following technical scheme: 1, a dynamic phase inheritance mechanism: through alternate work of double DDS modules, seamlessly transmitting an integer part and a decimal remainder contained in a phase accumulated value of a main DDS to a standby DDS during switching, and combining a shared clock source and a high-speed multiplexer to ensure phase continuity; 2, remainder compensation closed-loop control is carried out, a remainder accumulator is designed to record truncation errors in real time, FTW is dynamically adjusted through a PID algorithm, and long-term frequency error closed-loop suppression is achieved in combination with feedback of an external frequency meter; 3, according to a dual-mode triggering strategy, time period triggering and phase threshold triggering are supported, switching logic is started when a triggering condition (a fixed period or a phase threshold theta th is set) is met, and the phase accumulated value theta 1 (t) and the remainder epsilon 1 of the DDS1 are transmitted to the DDS2. According to the invention, through dynamic phase synchronization and closed-loop compensation, the problems of DDS phase accumulative errors and switching discontinuity are systematically solved.
Owner:GUILIN UNIV OF ELECTRONIC TECH +1
Surface acoustic wave hydrogen sensor based on platinum and graphene composite film as well as manufacturing method and application of surface acoustic wave hydrogen sensor
PendingCN121068749AAnalysing fluids using sonic/ultrasonic/infrasonic wavesLiquid surface applicatorsHemt circuitsData acquisition
The invention discloses a surface acoustic wave hydrogen sensor based on a platinum and graphene composite film and a manufacturing method thereof, and belongs to the technical field of gas sensors, the surface acoustic wave hydrogen sensor comprises a piezo-electric crystal, the piezo-electric crystal is oppositely provided with a first interdigital transducer and a second interdigital transducer, a graphene film is deposited on the piezoelectric crystal and located on a sound propagation path between the first interdigital transducer and the second interdigital transducer, a platinum catalyst layer film is deposited on the surface of the graphene film, and the first interdigital transducer and the second interdigital transducer are connected with an external circuit through metal pins. The external circuit comprises a signal generator, a frequency meter and a data acquisition system, the signal generator generates an excitation signal and transmits the excitation signal to the first interdigital transducer through the metal pin, and a detection signal generated by the interdigital transducers is received by the data acquisition system and then is detected and compared through the frequency meter. The problems that an existing pure graphene hydrogen sensor is low in sensitivity, poor in selectivity and slow in response time can be solved.
Owner:STATE GRID JIANGSU ELECTRIC POWER CO LTD RESEARCH INSTITUTE +1
A method for identifying sudden ionospheric disturbance events based on ionospheric vertical sounding data
The present invention discloses a method for identifying sudden ionospheric disturbance events based on ionospheric vertical sounding data, comprising the following steps: Step 1, collecting and organizing fmin and foF2 data from each ionospheric observation station during a historical M5.0 solar flare eruption that occurred during daytime in my country; Step 2, calculating the ratio of fmin to foF2 data at each ionospheric observation station at the corresponding time, statistically analyzing the distribution of fmin / foF2, and determining the different intensity levels of ionospheric absorption at each ionospheric observation station; Step 3, determining the intensity level of the sudden ionospheric disturbance event. The method for identifying sudden ionospheric disturbance events disclosed by the present invention utilizes the minimum echo frequency of the ionospheric vertical sounding ionogram and the ionospheric critical frequency to calculate an absorption index representing the degree of ionospheric absorption. This method can simply and directly characterize the degree of ionospheric absorption in a certain region and can provide ionospheric absorption information for different regions of my country for shortwave and other electronic information systems.
Owner:CHINA INST OF RADIO PROPAGATION
Method for improving PT residual voltage frequency measurement accuracy based on rotation vector characteristics
PendingCN121689952AElectronic commutation motor controlVector control systemsVoltage amplitudeFrequency measurements
The invention provides a method for improving PT residual voltage frequency measurement accuracy based on rotation vector characteristics, and relates to the technical field of generator set rotation speed measurement. The method comprises the following steps: acquiring a three-phase voltage alternating current signal through a generator end PT; processing the three-phase voltage signal to obtain projections of a voltage rotation vector on alpha and beta static coordinate axes; frequency characteristics are extracted based on projection and voltage amplitude and can be realized through direct calculation or a phase locking link; performing low-pass filtering on the frequency characteristic direct current quantity; a generator speed is calculated based on the filtered frequency and provided to a governor. According to the method, the limitation that a traditional PT residual voltage method only depends on zero crossing point information is broken through, frequency characteristics are extracted through a complete voltage sequence, alternating current signal filtering distortion is avoided through direct current filtering, high measurement precision and high anti-interference capacity can still be kept under the low-speed working condition, the problems that an existing speed measurement method is insufficient in precision and weak in anti-interference capacity are effectively solved, and the method is suitable for popularization and application. And reliable guarantee is provided for safe and stable operation of a unit.
Owner:CHINA YANGTZE POWER
An oil and gas detection method and device based on instantaneous energy frequency value and electronic equipment
The application provides an oil and gas detection method and device based on instantaneous energy frequency value, a computer readable storage medium and an electronic device. The method comprises the following steps: for each seismic signal in a three-dimensional seismic data volume of a target area, decomposing the seismic signal into a data set composed of a plurality of IMF components, extracting the instantaneous amplitude and instantaneous frequency of each IMF component, calculating the instantaneous energy frequency value of each IMF component based on the instantaneous amplitude and instantaneous frequency, and calculating the instantaneous energy frequency value of the seismic signal based on the instantaneous energy frequency value of each IMF component; analyzing the change characteristics of energy and frequency in the stratum of the target area based on the instantaneous energy frequency value of each seismic signal in the three-dimensional seismic data volume and the instantaneous energy frequency value of each IMF component of each seismic signal, and further analyzing the oil and gas bearing property of the stratum. The method provided by the application can more accurately identify the energy and frequency anomalies in the stratum and can also assist in oil and gas identification.
Owner:CHINA PETROLEUM & CHEMICAL CORP +1
Hybrid high-precision frequency weighting method and system and electronic equipment
The invention discloses a hybrid high-precision frequency weighting method and system and electronic equipment, and the method comprises the steps: obtaining an original sound signal, carrying out the analog-to-digital conversion, and carrying out the preprocessing of the sound signal after the analog-to-digital conversion, so as to obtain a signal frequency spectrum; segmenting the signal spectrum, and weighting each segment to obtain a first weighting sound level and a second weighting sound level; superposing the first weighted sound level and the second weighted sound level to determine a total weighted sound level; and performing dynamic error calibration on the total weighted sound level, determining a standard error, and when the standard error is smaller than or equal to a preset error threshold value, outputting the total weighted sound level. According to the invention, a differentiated optimization strategy is adopted, and the attenuation deviation of a traditional digital filter in a low-frequency area is effectively corrected in a low-frequency band; in the middle and high frequency bands, the accuracy is ensured, meanwhile, the occupation of operation resources is remarkably reduced, the signal processing delay time is shortened, and the response requirement of real-time noise monitoring can be met.
Owner:CHINA ELECTRIC POWER RESEARCH INSTITUTE CO LTD
Three-phase motor open-phase dynamic response judgment method
PendingCN120928186APolyphase network asymmetry measurementsDynamo-electric machine testingFrequency changerPhase currents
Owner:TIANJIN RES INST OF ELECTRIC SCI
A high-precision and fast calculation method for power grid frequency
ActiveCN114912485BInformation technology support systemComplex mathematical operationsAlgorithmFrequency meter
The present invention discloses a method for high-precision and rapid calculation of power grid frequency, which comprises the following steps: a high-speed acquisition card acquires a secondary voltage signal of the power grid; the voltage signal is subjected to high-precision analog-to-digital conversion; the converted signal is subjected to a high sampling rate to acquire a voltage signal; the voltage signal is resampled; the resampled signal is subjected to frequency calculation; the position of the sampling point where the primary threshold is located is obtained by verifying the resampling period using a threshold and a secondary threshold in sequence; the resampled signal is restored to the original signal and high-precision frequency calculation is performed again; and the actual frequency of the power grid is obtained. The present invention greatly reduces the amount of calculation without changing the frequency calculation accuracy, saves calculation time, and ensures the accuracy and real-time performance of the power grid frequency calculation. At the same time, the secondary threshold introduced in the method eliminates the influence of interference signals, avoiding calculation errors caused thereby.
Owner:GUIZHOU POWER GRID CO LTD +1
Radar control device and method
The present embodiments relate to a technology for a radar control device and method for transmitting a transmission signal, receiving a reception signal, controlling to change a frequency of the transmission signal at a preset interval, calculating a frequency deviation between the transmission signal and the reception signal, and extracting the interference signal based on the frequency deviation to extract and remove an interference signal causing ghosting in a radar device.
Owner:HL KLEMOVE CORP
Adjusting and measuring method and system for a photovoltaic power plant
A method for adjusting and measuring a photovoltaic power plant including a photovoltaic string having solar panels in series and an inverter to convert a DC voltage generated by the photovoltaic string into an AC voltage, the inverter having a DC-voltage inputs, includes:measuring a frequency of an AC voltage generated by the photovoltaic power plant and computing a frequency variation of the AC voltage with respect to a reference frequency and computing a power variation applied by the photovoltaic power plant based on the frequency variation,selecting a DC-voltage input, being the i-th input, to measure a curve of current vs. voltage of the input, having an initial DC voltage, thencomputing a residual power variation applied by the photovoltaic power plantif the residual power variation is non-zero, distributing it over inputs different from the i-th input,repeating the steps to create different points of the measured curve.
Owner:COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
A modal frequency-based multi-span pipeline discrimination method
ActiveCN116415402BOptimize supplementation methodsOptimize the replenishment processSustainable transportationDesign optimisation/simulationStructural engineeringFrequency meter
The application provides a modal frequency-based multi-span pipeline discrimination method, which comprises the following steps: S1, calculating a single-span modal frequency f0 of a suspended pipeline A section; S2, calculating a multi-span modal frequency f of the suspended pipeline A section i ; S3, calculating a difference between the single-span modal frequency f0 and the initial multi-span modal frequency f i , and comparing a ratio of the difference to the single-span modal frequency f0 with a predetermined threshold value to determine an initial critical span length ratio; S4, gradually increasing an initial span interval ratio α1 by a predetermined span interval ratio interval γ to obtain a plurality of equally-spaced span interval ratios and critical span length ratios corresponding to each span interval ratio; S5, drawing a multi-span discrimination curve, and discriminating a suspended pipeline section under a working condition of the suspended pipeline A section based on the multi-span discrimination curve. The method judges the influence degree between spans according to the change of the pipeline modal frequency under different span interval ratios and span length ratios, and improves the discrimination accuracy.
Owner:CHINA PETROLEUM PIPELINE ENG CO LTD +2
A method and system for braking an automated door machine
The application discloses a brake method and system of an automatic portal crane, and the method comprises the following steps: setting a target position of a grab bucket when braking is needed; and cyclically executing the following steps a to e until a difference between an actual position of the grab bucket and a stopping position is less than or equal to a threshold value, and outputting a frequency converter shutdown instruction and a brake starting instruction: a. collecting a real-time frequency of the frequency converter; b. calculating the actual position of the grab bucket; c. calculating a theoretical stopping distance under a current real-time frequency; d. compensating the theoretical stopping distance by considering a load; and e. calculating the stopping position based on the target position of the grab bucket and the compensated stopping distance. The application solves a long-existing problem of 'incompatibility between speed and accuracy' in the field of crane positioning by means of a trinity of non-linear modeling, dynamic calculation and data driving, and provides high-efficiency automatic operation for port automation.
Owner:JIANGSU SUGANG INTELLIGENT EQUIP IND INNOVATION CENT CO LTD
Test method and platform of target capture square wave signal frequency calculation module
The invention provides a test method and platform for a target capture square wave signal frequency calculation module. The method comprises the following steps: S1, determining a plurality of target capture square wave signal waveform templates which correspond to a tested module and meet preset test requirements; s2, generating a plurality of target capture square wave signals which respectively correspond to the plurality of target capture square wave signal waveform templates, meet preset test requirements and are adjustable in single period; s3, selecting a target capture square wave signal and inputting the target capture square wave signal into the tested module; s4, executing the tested module to obtain a target capture square wave signal frequency measured value; s5, judging whether the measured frequency value of the target capture square wave signal is consistent with the expected frequency value of the target capture square wave signal or not; the target capture square wave signal frequency expected value is calculated based on a target capture square wave signal input into the tested module; and S6, under the condition of consistency, determining that the test result is passed. According to the scheme, the function test, the boundary test and the like of the target capture square wave signal frequency calculation module can be more accurately carried out.
Owner:SHANGHAI AEROSPACE COMP TECH INST
Rotating speed measuring device and rotating speed measuring method
PendingCN121068945ALinear/angular speed measurementCounting mechanisms/objectsMicrocontrollerFrequency meter
The invention discloses a rotating speed measuring device and method, and the method comprises the steps: enabling a PI input square wave signal to sequentially pass through a square wave shaping unit, a sampling and counting unit, a sliding window processing unit and a rotating speed calculation unit in an MCU microcontroller for processing, and obtaining a rotating speed measurement result; the square wave shaping unit is used for processing complementation shaping of PI input square wave signals and sending complementation shaping square waves to the sampling counting unit; the sampling counting unit judges a square wave counting value input into the sliding window processing unit according to comparison between an absolute value of a counting difference value of two adjacent square waves and an allowable error threshold value; the sliding window processing unit automatically adjusts the depth of the sliding window according to the input square wave count value; the sliding window processing unit sends the adjusted window depth to the rotating speed calculation unit, the rotating speed calculation unit calculates the rotating speed according to the adjusted window depth, the self-adaptive sliding window depth is adopted, different depth windows are adopted for different frequency signals for frequency calculation, and the operation complexity is reduced.
Owner:HANGZHOU KANGJISEN AUTOMATION TECH CO LTD