10 results about "Harmonic energy" patented technology

This invention provides a non-destructive testing method and apparatus for defects in ferromagnetic pipes, belonging to the field of pipe inspection. The method includes: acquiring a voltage signal, which is obtained by converting the capacitance change signal continuously collected by the bipolar capacitor as the ferromagnetic pipe and the upper and lower semi-circular bipolar capacitor move at a constant axial velocity relative to each other; extracting time-domain and frequency-domain features from the voltage signal; and determining the defect type and location based on the voltage signal and the extracted features. The extracted features include time-domain and frequency-domain features; the time-domain features include the signal standard deviation, coefficient of variation, and density of local extrema; and the frequency-domain features include the dominant frequency component and harmonic energy ratio. This method utilizes the physical property that the dielectric constant of a ferromagnetic pipe differs depending on whether it has defects or not, enabling the detection of defects deep within the component. It effectively avoids interference from various environmental electromagnetic noises, ensuring the accuracy of the detection results, and eliminates the need for point-by-point scanning, resulting in higher detection efficiency.

This application provides a PWM control method for avoiding eddy current losses in LED power supply cores, comprising: generating a basic modulation sequence from an asymmetric pulse width modulation chaotic mapping; extracting the main frequency bands of harmonic energy distribution of the basic modulation sequence; determining the degree of overlap between the main frequency bands of harmonic energy distribution and the expected position range; if the overlap ratio exceeds a preset threshold, activating a frequency avoidance mechanism; comparing the spectrum of the offset modulation sequence with that of the basic modulation sequence to determine the degree of preservation of spectrum broadening characteristics and the change in energy distribution; if the degree of preservation of spectrum broadening characteristics is lower than a preset preservation range, reducing the offset and re-executing the frequency avoidance mechanism; and feeding back ripple data and temperature increments collected during actual operation to the sensitive interval prediction model to update the internal state of the sensitive interval prediction model.

The application provides an arc high-resistance fault line selection method for an active small-resistance grounding system. Zero sequence currents of first ends of each feeder after fault occurrence are collected; fundamental wave, third harmonic and fifth harmonic in the zero sequence currents are extracted by using empirical wavelet decomposition; third harmonic and fifth harmonic energy of each feeder within a quarter of a cycle after the fault is calculated, and E i The three groups of harmonic energy with the largest amplitude and corresponding feeders g, m and k are selected; based on the fundamental wave, third harmonic and fifth harmonic extracted from the feeders g, m and k, a harmonic matrix H g , H m , H k is constructed; if SSIM(H g , H m ) < SSIM(H m , H k ) and SSIM(H g , H k ) < SSIM(H m , H k ), the feeder g is the fault feeder, and the others are healthy feeders, otherwise, step 1 is returned to re-collect. The application significantly improves the sensitivity and accuracy of the line selection method.

This application provides a motion control method and device. The method includes acquiring current signals from the joint motors of a robot, extracting harmonic features from the current signals, wherein the frequency of the harmonic features is greater than a preset frequency, and the preset frequency is greater than or equal to the natural vibration frequency of the mechanical transmission chain corresponding to the joint motor; determining a harmonic energy index based on the harmonic features, wherein the harmonic energy index is related to the disturbance intensity experienced by the mechanical transmission chain; and performing motion control on the robot based on the harmonic energy index. The method provided in this embodiment achieves collision precursor detection without the need for external force sensors, improving interaction safety, operational accuracy, and device adaptability.

This invention discloses a method and system for metering unsteady-state harmonic energy based on dynamic mirror extension, relating to the field of energy metering technology. The method extracts the instantaneous frequency of the unsteady-state harmonic signal through Hilbert transform, calculates the optimal reversal point spacing, and sets reversal points only at integer multiples of the optimal reversal point spacing. This solves the problem of phase reversal point distortion caused by the frequency variation of unsteady-state harmonic extrema in traditional mirror extension, effectively suppressing the endpoint effect, improving the signal-to-noise ratio of the extension segment, and enhancing the accuracy of energy metering.

The application discloses a kind of harmonic metering method, medium, system and harmonic watt-hour meter, method includes the following steps: S1, the voltage and current of three-phase power grid are obtained, obtain the discrete voltage sample value sequence and current sample value sequence, and the period value of voltage is calculated;S2, according to the period value of voltage, voltage sample value sequence and current sample value sequence are interpolated and resampled;S3, the voltage sample value sequence and current sample value sequence after interpolation and resampling are analyzed by FFT transform, and FFT analysis result is obtained;S4, according to FFT analysis result, harmonic voltage, harmonic current and total harmonic active power are calculated.The application realizes sampling synchronization processing by Lagrange polynomial interpolation and resampling technology, improves harmonic analysis accuracy;And the corresponding compensation is carried out to harmonic amplitude error, further improves harmonic analysis accuracy.

The present application belongs to the technical field of power quality measurement, and provides a harmonic distortion type identification method and system based on symmetry characteristics, which obtains power signal data according to a preset sampling window sliding; processes the obtained data, extracts harmonic components, calculates single-window harmonic energy variance indexes, performs grouping processing, compares with a preset center-symmetry normalized mean square error threshold, judges whether each group of data conforms to center-symmetry distribution, and then compares with an error threshold of inter-harmonic characteristics to obtain an inter-harmonic criterion variable; processes, calculates and analyzes time domain data of any complete single period, compares the consistency degree of the translated first half cycle data and the inverted second half cycle data to obtain an even harmonic criterion variable; and comprehensively identifies the signal harmonic distortion type according to the inter-harmonic criterion variable and the even harmonic criterion variable. The present application realizes accurate identification of the power signal harmonic distortion type.

This invention belongs to the field of power quality measurement technology, specifically disclosing a harmonic measurement and evaluation method and system based on time-domain statistics. The method includes: acquiring the time-domain waveform signal of the power signal containing harmonic information for each sliding window; calculating the single-window harmonic energy variance index using statistical calculation methods; grouping the discretized single-window harmonic energy variance index according to the required frequency resolution; determining whether each group of data exhibits a centrally symmetrical distribution within acceptable error limits; if so, calculating the harmonic energy variance index for harmonic distortion evaluation with a preset period length; and establishing the correspondence between the harmonic energy variance index and the total harmonic distortion rate index, thereby intuitively evaluating the harmonic distortion of the power system. This invention enables lightweight data calculation, improves data processing efficiency, and can meet the needs of online monitoring to a certain extent.

This application provides a method for dynamically adjusting the output gain of a sound card, relating to the field of audio signal processing technology. The method includes: separating the components of the sound card's output signal through harmonic extraction and noise analysis; calculating the harmonic-to-noise ratio and comparing it with a preset threshold to identify the air-sound mode; dynamically evaluating the proportion of harmonics and noise in the total signal energy; adjusting the energy classification criteria based on the noise bandwidth, tilting towards harmonic energy; and calculating and applying the target gain of the harmonic components, replacing the uniform boosting method based on total energy. The beneficial effects of this application are: by identifying the harmonic-to-noise ratio and adaptively classifying the bandwidth, it accurately boosts the harmonic level in the air-sound mode, avoiding the contradiction of simultaneous amplification of harmonics and broadband airflow noise in the traditional uniform gain mode, achieving a dynamic balance between improving vocal clarity and suppressing noise, and significantly optimizing the intelligibility and quality of the sound card's output signal in the air-sound mode.

The application discloses a road construction quality detection method based on an intelligent sensor, which comprises the following steps: step one, collecting drum vibration acceleration signals and performing sliding time window segmentation to form a vibration signal segment sequence; step two, performing direct current removal on the vibration signal segment sequence and calculating a frequency spectrum amplitude distribution to screen effective vibration signal segments; step three, extracting a main peak coupling frequency, a half-power bandwidth, a harmonic energy ratio and a self-correlation delay parameter to construct a characteristic vector; step four, normalizing the characteristic vector and calculating a vector angle to obtain a characteristic angle distance mapping value; step five, constructing a characteristic spectrum representation matrix by using an improved Gegenbauer polynomial and a fractional order modulation; step six, performing a fractional order spectrum operator mapping calculation to obtain a construction quality calculation value; and step seven, performing section determination according to a quality threshold value. The application realizes stable detection and evaluation of road construction quality.