63 results about "Harmonic spectrum" patented technology

The invention discloses a power supply real-time compensation technology and application based on digital signal processing, and relates to the technical field of power electronics, and the power supply real-time compensation technology comprises a split-phase parallel processing architecture: a three-phase independently configured DSP core, each core integration comprises a real-time harmonic detection module, a dynamic sliding window FFT-RT algorithm is adopted, and the window length is adjustable in a set range; the bandwidth of the self-adaptive variable parameter filter can be dynamically adjusted in a set range; the FPGA coprocessor is specially used for PWM generation; an input stage of the harmonic prediction and decomposition module is synchronously acquired by a multi-source sensor; the processing layer comprises an improved VMD decomposition unit and a variational mode decomposition order; the edge prediction network is used for deploying a lightweight LSTM model, embedding a DSP core and predicting a harmonic spectrum in a future short period; and the multi-target dynamic optimization layer is used for setting a dynamic weight distributor and performing real-time adjustment according to the load sudden change rate. According to the invention, through split-phase parallel architecture, harmonic prediction and dynamic optimization, the response speed, multi-target cooperation and reliability improvement in the field of power supply real-time compensation are realized.

The invention discloses a gradient welding strength control method and system for a welded galvanized steel pipe for fire fighting, particularly relates to the technical field of welding automation control, and aims to solve the problem of abnormal welding seam strength gradient caused by instantaneous unbalance of an electric field and a thermal field during dynamic parameter switching in the prior art. Electromagnetic distortion characteristic quantity is extracted through frequency domain energy analysis, and thermodynamic offset state quantity is deduced in combination with a thermal diffusion trend; on the basis of frequency band correlation mapping of electromagnetic and thermodynamic parameters, thermoelectric cooperative imbalance levels are divided through mutual information entropy evolution, and a self-adaptive harmonic attenuation weight tuning instruction is generated; analyzing a mismatching relation between transient disturbance of an environment magnetic field and arc voltage modulation distortion in real time, dynamically generating a magnetic field compensation factor and reversely superposing the magnetic field compensation factor to a control instruction; and in combination with the matching degree of molten pool oscillation energy and a harmonic frequency spectrum, correcting wire feeding rate calibration, reconstructing a multi-band harmonic energy proportion spectrum, outputting an anti-interference welding control signal, and realizing dynamic balance between arc stability and molten pool heat input.

The invention discloses a spectral gas concentration inversion method based on a CNN-Transform fusion model, and belongs to the technical field of trace gas detection and spectral signal processing. The method comprises the following steps: acquiring second harmonic spectrum data of target gas through a TDLAS (tunable diode laser absorption spectroscopy) system; carrying out abnormal value elimination and smooth filtering processing on the acquired signal, and constructing a standard input vector; a depth model fusing a one-dimensional convolutional neural network (CNN) and a Transform architecture is designed, the CNN is used for extracting local spectrogram features, and the Transform is used for modeling a global dependency relationship; and inputting the training set and the verification set into the model for training optimization, and finally realizing high-precision inversion of the sample gas concentration of the test set. Experimental results show that the method is superior to an existing model in the aspects of fitting precision, robustness and error control, and has good physical consistency and engineering popularization value.

The invention relates to the technical field of gas detection, and provides a doped gas concentration detection method and system based on a gas analyzer. The method comprises the following steps: constructing a standard spectrum database under the same pressure and temperature as a to-be-measured site; the method comprises the following steps: introducing sample gas into an optical absorption cell, carrying out wavelength scanning through a tunable diode laser in a plurality of adjacent absorption spectral line intervals containing target gas and interference gas, superposing a high-frequency sinusoidal modulation signal on a driving current, and synchronously detecting a second harmonic component of transmission laser to generate an actual measurement spectrum; fitting the actually measured spectrum with a synthetic spectrum generated on the basis of a standard spectrum database, and outputting a target gas concentration ratio as a detection result when a residual error meets a threshold value, so as to solve the technical problem that the detection precision is reduced due to spectrum overlapping caused by interference gas, and achieve the purpose that the detection precision is reduced by constructing the standard spectrum database and second harmonic spectrum fitting analysis. And the accuracy and the anti-interference capability of gas detection are improved.

The invention discloses a method and device for preventing inverter harmonic waves from affecting operation of an electric energy meter, and the method comprises the following steps: a harmonic attenuation device is installed on an inverter line bus, and the harmonic attenuation device comprises an LC resonance circuit and a control circuit; dynamically matching the winding inductor and the safety capacitor based on the harmonic frequency spectrum characteristic of the inverter; a temperature sensing module is integrated on the body of each power resistor branch; the MCU microcontroller judges whether to trigger power resistor branch switching or not based on the temperature data and a preset temperature control strategy; after a relay switching action is triggered, a dynamic compensation strategy is generated to dynamically adjust inductance, capacitance and resistance topology so as to realize frequency stabilization and impedance matching; and executing closed-loop feedback optimization and health assessment based on the harmonic suppression effect after dynamic compensation and the system operation state. The invention has the following advantages and effects: the dynamic tracking of the LC resonant frequency on the harmonic dominant frequency is realized, and the thermal runaway problem of the harmonic energy absorption unit is synchronously solved.

The invention relates to the technical field of stepping drive motor control, and discloses a stepping drive motor resonance control method and system for a high-precision scene, and the method comprises the steps: collecting motor operation data through a multi-dimensional detector array, and inputting a dynamic response model to obtain dynamic response features; extracting a current harmonic frequency spectrum key point as a resonance event mark point, aligning and matching a rotor angular displacement and winding temperature data fluctuation interval, and generating a mechanical response association pair; performing resonance event association and space-time positioning by using the association pair, and determining abnormal response distribution; and generating a self-adaptive suppression strategy based on the association pair and the abnormal distribution and triggering an execution device. The system comprises a multi-dimensional detector array, a dynamic response processing module, an event association analysis unit, an abnormal distribution modeling unit and a strategy execution unit. According to the invention, multi-physics field data fusion analysis and resonance precise control are realized, the method is suitable for high-precision scenes, and the motor operation stability and reliability are improved.

The invention belongs to the technical field of power generation and power supply, and particularly relates to a power distribution network electric energy quality monitoring and comprehensive evaluation method and system, and the method comprises the steps: obtaining an environment reference parameter, three-phase voltage data, three-phase current data, transformer harmonic current and transformer harmonic current times; calculating a transformer voltage distortion rate and a transformer total current which represent the overall level of the electric energy quality; calculating a harmonic erosion index representing the load side harmonic frequency spectrum complexity; calculating a thermal harmonic coupling degree used for judging a high temperature generation reason; calculating a power grid health score; grading the operation state of the power grid; judging the fault type; and issuing adjustment instructions to different fault types. The technical problem that the dynamic coupling relation between the harmonic form and the equipment thermal state cannot be evaluated in the prior art is effectively solved.

The invention discloses a harmonic spectrum information cutting-based flood inundation range remote sensing rapid extraction method, which comprises the steps of S1, converting an obtained remote sensing image from an RGB color space to an HSV color space, extracting spectral information of the image, and decomposing the spectral information into harmonic spectrum components; s2, constructing an improved clustering model based on a density peak value clustering algorithm, and clustering pixel points in the remote sensing image into a suspected water body class and a non-water body class; s3, optimizing a clustering result through a semantic segmentation network, taking the clustered image as input, and outputting a water body and non-water body segmentation result; and S4, in combination with geographic coordinate information of the remote sensing image, geocoding is performed on the segmentation result, and a thematic map containing the flood inundation range is generated. According to the method, the accuracy and efficiency of flood inundation range extraction are improved, and accurate distinguishing between a water body and a non-water body and rapid obtaining of inundation range changes are achieved.

The invention provides a harmonic detection method and device based on moving average filtering. The actual voltage and the actual current of a node in a power grid can be converted to obtain first harmonic spectrum data. Wherein the first harmonic frequency spectrum data comprises harmonic voltage and harmonic current. And performing moving average filtering on the first harmonic spectrum data to obtain second harmonic spectrum data. And grouping the second harmonic spectrum data, and detecting the center frequency of the harmonic according to a plurality of grouping results. The moving average filtering is carried out on the first harmonic spectrum data, so that the problem of discontinuous spectrum groups in groups caused by low amplitude of partial frequencies is avoided, the reliability of a grouping result is improved, and the accuracy of harmonic detection is further improved.

The present application provides a non-periodic time modulation corner reflector with wide-angle regulation and a harmonic spectrum conversion method thereof, the reflector comprising a time modulation metasurface and a three-face corner reflector structure; wherein the time modulation metasurface is a single plane structure composed of an active adjustable metasurface and a field programmable gate array (FPGA) time modulation control system. The conversion method comprises the following steps: step one, wide-angle time modulation corner reflector design; step two, non-periodic time modulation model establishment based on the wide-angle time modulation corner reflector; and step three, continuous harmonic spectrum conversion method based on the wide-angle time modulation corner reflector. The present application effectively improves the wide-angle stability of the time modulation metasurface by combining the time modulation metasurface with the corner reflector, and can control the harmonic spectrum distribution of the backward reflected electromagnetic wave in a wide-angle range. At the same time, a non-periodic time modulation model is established from the signal level, and the effect of reflective continuous harmonic spectrum conversion is realized.

The application discloses a kind of interval harmonic power flow calculation method using relative distance measure, first input the parameter of power grid and network fluctuation, construct the node admittance matrix of fundamental wave and harmonic, set the RDM initial value of node voltage and carry out fundamental wave power flow iteration calculation, in the process of fundamental wave power flow iteration, the correction of reactive power injection and voltage is carried out to PV node, after meeting convergence condition, the RDM number of the fundamental wave voltage and injection current of whole network is output. After that, the harmonic power flow iteration part in decoupling method is further simplified by using simple solution method. The harmonic current is calculated at harmonic source node in combination with harmonic spectrum, and then the harmonic admittance matrix in RDM form is established based on the harmonic model of each element in the whole network, and the harmonic voltage RDM value of each node is obtained through the harmonic voltage equation. Finally, the interval number is converted through the conversion principle of RDM number, and the harmonic voltage interval range of the whole network is obtained, which can be applied to harmonic analysis and treatment.

The invention discloses an operation control method and system of a direct-drive motor, and relates to the technical field of control of the direct-drive motor, and the method comprises the steps: collecting three-phase voltage fluctuation data in real time, extracting a harmonic spectrum in combination with frequency domain analysis, preliminarily estimating the conduction delay and dead-zone compensation time, and increasing dead-zone compensation to form a preliminary optimization parameter when low-order harmonics exceed the standard; and then neutral point deviation, common-mode voltage and three-phase asymmetry degree are evaluated through waveform simulation, finally, a swarm intelligence optimization algorithm is adopted to iteratively adjust a potential balance correction coefficient, conduction delay, dead zone compensation and an interphase time sequence deviation angle to obtain a target time sequence parameter, and a three-phase switch control instruction is generated to be applied to a control system. According to the invention, in the control of the high-power direct-drive motor, the harmonic interference is effectively reduced by optimizing the time sequence design of the switching action, meanwhile, the system risk caused by potential imbalance is avoided, and the operation stability and reliability of equipment are improved.

The invention discloses an urban community household charging pile harmonic suppression method, which comprises the following steps: S1, collecting voltage and current data of a charging pile under different working conditions, analyzing harmonic generation characteristics, constructing a harmonic mathematical model, and determining typical harmonic frequency and amplitude range; s2, an FPGA real-time data processing architecture is designed according to the harmonic model, a high-speed data acquisition module is established, and real-time acquisition and accurate identification of harmonic signals are realized; s3, on the FPGA platform, based on the real-time harmonic spectrum data, deploying an adaptive harmonic suppression algorithm, dynamically filtering the target harmonic frequency, and reducing the harmonic content; and S4, according to suppression effect feedback, FPGA control parameters are optimized, energy consumption and cost of the device are reduced, and precise and efficient harmonic suppression performance and economical efficiency balance is achieved. The method can ensure that the current waveform of the charging pile meets the power grid standard, remarkably improves the harmonic suppression efficiency and the economical efficiency of the device, and reduces the energy consumption and the equipment maintenance cost.

This invention belongs to the field of power generation and supply technology, specifically relating to a method and system for monitoring and comprehensively evaluating the power quality of distribution networks. The method includes: obtaining environmental reference parameters, three-phase voltage data, three-phase current data, transformer harmonic current, and transformer harmonic current order; calculating the transformer voltage distortion rate and total transformer current, which characterize the overall power quality level; calculating the harmonic erosion index, which characterizes the complexity of the harmonic spectrum on the load side; calculating the thermal harmonic coupling degree used to determine the cause of high temperatures; calculating the grid health score; classifying the grid operating status into levels; determining the fault type; and issuing adjustment commands for different fault types. This invention effectively solves the technical problem that existing technologies cannot assess the dynamic coupling relationship between harmonic morphology and equipment thermal state.

The embodiment of the specification provides a bearing fault diagnosis method and system of optimized filtering MCKD, wherein the method comprises the following steps: collecting a vibration signal, performing Fourier transform on a frequency spectrum of the vibration signal to obtain a key function; setting an initial truncation length, performing inverse Fourier transform on the key function based on the initial truncation length to obtain a frequency spectrum trend, taking a minimum value of the trend spectrum as a boundary of spectrum segmentation to divide a filtering frequency band with different bandwidths and center frequencies, increasing the truncation length, repeating the above steps, and recording all results; designing a Mayer wave filter based on the obtained filtering frequency band, and taking the designed Mayer wave filter coefficient as an initial filter coefficient of the MCKD; calculating MCKD filtering results of different initial filter coefficients, quantifying fault characteristics of all filtering signals by a harmonic spectrum kurtosis (HSK), selecting a filtering result corresponding to a maximum value of the HSK as a global optimal solution of the MCKD, and completing fault diagnosis.

The application provides a temperature and concentration reconstruction method based on a normalized second harmonic linear model, belongs to the technical field of tunable diode laser absorption spectroscopy, and is used for two-dimensional temperature and concentration field reconstruction. The reconstruction system comprises a laser control and generation module, a fiber beam splitter, a sensor, a Mach-Zehnder interferometer, a photodetector, a data acquisition system and a computer. The reconstruction method comprises the following steps: after laser is split, one path is connected to the Mach-Zehnder interferometer and is received by the photodetector, the remaining paths pass through the to-be-detected area after being expanded and are received by a photodetector plate, and normalized second harmonic spectra of transmitted light intensities on each light path are obtained; a normalized second harmonic base matrix is calculated according to discrete temperature and concentration; a linear reconstruction model is established according to the sensor light path arrangement, and an iterative algorithm is used to obtain two-dimensional temperature and concentration distribution. The application effectively utilizes the normalized second harmonic spectrum, increases the number of independent equations, and improves the speed and accuracy of two-dimensional temperature and concentration distribution reconstruction.

The present invention discloses a low-voltage intelligent broadband harmonic detection method and a detection device, belonging to the technical field of harmonic detection in power systems, including: denoising an input signal to obtain an initial signal; performing discrete wavelet transform based on the obtained number of transformation times to separate the initial signal into a low-frequency signal and a high-frequency signal; weighting the low-frequency signal based on a Hanning window to obtain a weighted signal, performing fast Fourier transform on the weighted signal to obtain a first harmonic spectrum, and performing feature extraction and spectrum correction on the first harmonic spectrum to obtain a first detection result; performing frequency reduction processing on the high-frequency signal through an orthogonal digital mixing function to obtain a frequency-reduced signal, performing band-selective fast Fourier transform on the frequency-reduced signal to obtain a second harmonic spectrum, and performing feature extraction on the second harmonic spectrum to obtain a second detection result. It overcomes the technical problem in the prior art that it is difficult to improve the real-time performance while improving the detection accuracy, and significantly improves the accuracy and real-time performance of harmonic detection.

The application discloses a harmonic and adjacent inter-harmonic parameter estimation method, comprising the following steps: S1, performing Fourier transform on sampling data of a preset time length to obtain frequency domain data; S2, based on the frequency domain data, calculating the amplitude, frequency and phase parameters of a fundamental wave by using a multi-layer interpolation method and removing the influence of the fundamental wave component, and calculating the mapping relationship of a leakage spectrum line and frequency offset of a harmonic component; S3, based on the spectral difference of a single adjacent inter-harmonic and a symmetric adjacent inter-harmonic pair, constructing an adjacent inter-harmonic type criterion, determining the threshold of the criterion according to the noise size in a power system to judge the adjacent inter-harmonic type information; and S4, constructing an adjacent inter-harmonic spectrum line equation set based on the adjacent inter-harmonic type information, and solving the adjacent inter-harmonic spectrum line equation set by using an eigenvalue decomposition method to obtain the amplitude, frequency and phase parameters of the harmonic and adjacent inter-harmonic. The application can judge the type of the inter-harmonic under the frequency offset scene of the power system.

The invention provides a harmonic detection method and device based on a grouped amplitude average value. And converting the actual voltage and the actual current of the node to obtain first harmonic spectrum data. And calculating a grouping amplitude average value, grouping the first harmonic frequency spectrum data according to the grouping amplitude average value, and detecting the center frequency of the harmonic according to the plurality of harmonic frequency spectrum groups. The first harmonic frequency spectrum data is grouped through the grouping amplitude average value, the rationality of the harmonic frequency spectrum group is improved, and then the detection accuracy of the harmonic center frequency is improved. According to the invention, under the condition that the switching frequency is unknown, the adjustment of the grouping amplitude average value is realized by adjusting the grouping amplitude upper limit or the grouping amplitude lower limit, and the grouping of the first harmonic spectrum data is adaptively realized according to the distribution characteristics of the first harmonic spectrum data and the grouping amplitude average value. And the harmonic center frequency is detected according to the harmonic spectrum group, so that the detection accuracy is improved.

The invention relates to the technical field of femtosecond pulse measurement, in particular to a dispersion scanning pulse self-measurement method based on a chirped pulse amplification laser, which comprises the following steps of: jointly using a stretcher and a compressor which are arranged in the laser as a dispersion scanning system, and adopting a dispersion scanning coordination strategy; continuously adjusting the dispersion amount of the stretcher and the dispersion amount of the compressor, synchronously collecting second harmonic spectrum signals under different dispersion distribution combinations, and constructing a second harmonic spectrum track diagram; according to the method, an adaptive dispersion coupling phase reconstruction algorithm is adopted, iteration processing is conducted on a second harmonic frequency spectrum track diagram, a high-order dispersion compensation item is introduced for optimization, the time domain intensity and phase information of laser pulses are reconstructed, the optimal dispersion compensation amount is determined, and the narrowest pulse width value is output. Therefore, the precision of pulse phase and width measurement and the convergence speed of the algorithm are improved.

The application relates to the technical field of industrial automation control and system state monitoring, and discloses a performance evaluation method and system of an industrial internet connector, which comprises the following steps: the method uses the common-mode noise generated in the power supply loop of the device itself as a diagnostic probe in reverse, establishes the intrinsic harmonic spectrum series relationship representing the stability of the noise source itself when establishing the initial frequency spectrum fingerprint baseline, and in the subsequent periodic evaluation, firstly, the spectrum series relationship is pre-checked, and then, based on the drift index of the current frequency spectrum fingerprint relative to the baseline and the change slope in the continuous time window, the performance evolution of the connector is evaluated. The application shifts the focus of evaluation from the apparent correctness of data transmission to the gradual change trend of the physical structure of the bearing connection, and can identify that the irreversible physical state degradation process of the connector is occurring.

The invention discloses a Nanyin instrumental analysis and music generation processing method and system, and belongs to the technical field of audio signal processing and computer music, and the method comprises the steps: 1, obtaining an original Nanyin sample, and measuring and recording a harmonic spectrum ratio curve, a formant displacement curve and a transient excitation contour in a short frame, forming a triple fingerprint set capable of being expressed by interpolation; step 2, according to the intention of a user, mapping intention primitives into curve offset of the triple fingerprint in the step 1, and generating a target fingerprint track; step 3, mapping the target fingerprint track in the step 2 into a superposable resonator coefficient sequence and an excitation element coefficient sequence; and step 4, according to the resonator coefficient sequence and the excitation element coefficient sequence obtained through mapping in the step 3. According to the invention, the degree of freedom of creation according to the intention of a user can be met, the cavity body feeling of linkage between the Nanyin pitch and the timbre intensity can be accurately reproduced, and the unnatural problem caused by disjunction of the pitch and the timbre is avoided.

The invention discloses an ammeter relay resonance fault detection method and system based on harmonic analysis, and relates to the field of electrical variable measurement, and the method comprises the steps: obtaining a current signal and a voltage signal, and carrying out the preprocessing, and obtaining a current analysis signal and a power grid harmonic spectrum of a current period; quantifying the resonance risk of the power grid based on the power grid harmonic spectrum to obtain a resonance sensitivity index of the power grid in the current period; presetting a candidate wavelet basis set, and obtaining a time-frequency focusing capability evaluation index and a task suitability index of each candidate wavelet basis in the set; based on the three indexes, constructing a dynamic comprehensive cost function and selecting an optimal wavelet basis; and performing wavelet packet decomposition on the current analysis signal based on the optimal wavelet basis, extracting fault features, and identifying and judging the current working state of the relay. According to the method, adaptive selection of the wavelet basis can be realized, and the problems of inaccurate fault feature extraction, high false alarm rate and unreasonable computing resource utilization of an existing detection method are solved.

The invention relates to a method for controlling one or more PWM inverters. The method comprises determining first and second periods of the first PWM inverter for operating the first PWM inverter with respective first and second switching patterns wherein the first and second switching patterns have different harmonic spectrums, and operating the first PWM inverter with the first and second switching patterns applied successively during the respective first and second periods.

The application relates to the technical field of power fault identification, and discloses a traveling wave fault positioning method and system. The method is used for positioning a traveling wave fault by screening two traveling wave collecting devices with opposite traveling wave directions and the closest distance, constructing a cubic B-spline wavelet as a wavelet base, performing wavelet decomposition on the traveling wave signals of the screened traveling wave collecting devices, obtaining the highest frequency harmonic component, simulating the harmonic component, determining the fault section in the direction of the first mutation point of the harmonic spectrum obtained through simulation at scale 1, obtaining the wavelet coefficient modulus maximum point at scale 4 of the harmonic spectrum and the corresponding modulus maximum value, calculating the fault time according to the modulus maximum value and the sampling frequency, and calculating the specific position of the fault point in the fault section by using the fault time, so that the fault positioning accuracy is improved.

This application provides a method and apparatus for suppressing transformer losses. It extracts the electromagnetic harmonic characteristic layer, vibration state characteristic layer, and heat loss characteristic layer of a large transformer from historical multi-source operating data. Based on real-time acquisition of the current multi-source operating data and electromagnetic harmonic characteristic layer, it determines the harmonic interference mode of the large transformer. It generates a harmonic compensation current for the harmonic interference mode using the vibration state characteristic layer and heat loss characteristic layer. Based on the compensated multi-source operating data of the large transformer, it generates the measured harmonic spectrum and measured vibration spectrum under the current operating conditions of the large transformer to correct the control parameters of the frequency conversion modulation circuit in the large transformer, thereby suppressing transformer losses. Using the scheme of this application, transformer losses can be synergistically suppressed based on the transformer's vibration state and heat loss characteristics.

The application discloses a running control method and system of a direct drive motor, relates to the technical field of control of the direct drive motor, and realizes the real-time collection of three-phase voltage fluctuation data, extracts a harmonic spectrum in combination with frequency domain analysis, and preliminarily estimates a conduction delay and a dead zone compensation time; when low-order harmonic exceeds a standard, the dead zone compensation is increased to form preliminary optimization parameters; subsequently, neutral point deviation, common-mode voltage and three-phase asymmetry are evaluated through waveform simulation; finally, a swarm intelligence optimization algorithm is adopted to iteratively adjust a potential balance correction coefficient, the conduction delay, the dead zone compensation and a phase-to-phase timing offset angle, target timing parameters are obtained, and three-phase switching control instructions are generated and applied to a control system. In the high-power direct drive motor control, the application realizes the timing design of optimized switching action, effectively reduces harmonic interference, avoids system risks caused by potential imbalance, and improves equipment operation stability and reliability.

The invention provides a rolling bearing fault diagnosis method, system and device based on a contig, and a medium, and the method comprises the steps: obtaining a vibration signal, and constructing a reweighted contig sparse shrinkage model through frequency slice wavelet transform based on a frequency slice function; then establishing a mathematical model framework taking harmonic spectrum kurtosis HSK and related Thire index CTI as double optimization objectives, and carrying out collaborative optimization on multiple parameters by using a multi-objective particle swarm optimization (MOPSO) algorithm to obtain optimal parameters; and finally, the optimal parameter is substituted into a model to strengthen a frequency domain resonance frequency band, an envelope demodulation spectrum is obtained through calculation, and fault feature frequency is extracted. The method can effectively separate fault impact components and noise interference, enhances fault feature sparse representation capability, improves diagnosis precision through dual-objective optimization, is suitable for fault diagnosis of rolling bearings under strong noise and complex working conditions, and has the advantages of high efficiency, accuracy, high adaptability and the like.

Disclosed is a method for detecting and classifying a flying insect. The method includes providing a radar sensor that is configured to transmit a radio wave of a predefined carrier frequency onto the flying insect, and recording a signal reflected from the flying insect, recording harmonic spectrum related to insect's wingbeat in the reflected signal, extracting a plurality of harmonic, spectral and temporal features from the harmonic spectrum resulting from the flapping of wings of the insect, selecting a plurality of relevant features from the extracted features, and analysing the extracted features for determining characteristics of the insect that allow its classification, by using signal processing techniques and machine learning model that is trained on features extracted from radar signatures of one or more flying insect species.

The invention discloses an impeller rotating machinery shaft frequency automatic extraction method based on improved correlation kurtosis, and the method comprises the steps: collecting an impeller rotating machinery radiation noise signal, and calculating a spectrum coherence function; calculating a related kurtosis matrix; screening spectrum coherence slices; calculating the entropy of the screened spectrum coherent slices; constructing a weighting function based on the spectral coherence slice entropy; performing frequency integration along the spectrum after weighting the spectrum coherent slice to obtain a weighted envelope spectrum; calculating a harmonic spectrum of the weighted envelope spectrum based on the improved correlation kurtosis; determining an axis frequency according to the harmonic spectrum peak; according to the method, the extraction modulation features can be enhanced according to the shaft frequency detection interval, and automatic extraction of the impeller rotating mechanical shaft frequency is achieved. According to the method, non-harmonic interference can be effectively suppressed, modulation characteristics are effectively enhanced, and the impeller rotating mechanical shaft frequency can be accurately extracted.