24 results about "Harmonic order" patented technology

The invention discloses a non-Gaussian noise pollution spiral shaft rod type part measurement signal processing method, which can realize reliable purification of measurement signals, stable separation of bending deviation and spiral raceway morphology items and fitting reconstruction when pollution such as heavy tails, multiple peaks, burrs and sheet abnormal points exists. The method comprises the following steps: acquiring and synchronously registering measurement data of rotation and axial movement, establishing a joint fitting model for decomposing readings into deformation items and spiral raceway morphology items, and expressing the morphology items by multi-order harmonics, and a three-stage process is adopted to complete baseline establishment and coarse elimination, phase locking and fine filtering in sequence, and the harmonic order of the optimal spiral raceway morphology item is determined in a self-adaptive manner and finally reconstructed. The invention provides an effective solution for the problems that the continuous rotary scanning measurement signal of the spiral shaft rod type part is unstable in recovery and is easy to distort in reconstruction under the non-Gaussian noise pollution.

The invention provides a power line carrier communication chip function test method and system, and relates to the technical field of communication technology, and the method comprises the steps: constructing a power line channel simulation test platform, and simulating the voltage fluctuation and power rapid switching working condition in an actual power grid through dynamically adjusting the power output and load switching; in the power line channel simulation test platform, the dynamic sudden change process of the power grid impedance is simulated by controlling the change rate of the load current; the method comprises the following steps: generating an interference signal containing multiple times of characteristic harmonics based on a preset harmonic order proportional relation while simulating dynamic sudden change of impedance, establishing an amplitude proportional coefficient between a reference harmonic and a target harmonic, and coordinating and setting the amplitude of each harmonic according to the proportional relation of the corresponding order, so as to simulate the dynamic sudden change of the impedance. A plurality of characteristic harmonics with a predetermined proportional relationship are obtained, and an interference signal is coupled to a power line channel. The method can accurately simulate the severe channel condition of an actual power grid, and accurately evaluates the communication reliability of the chip.

The invention relates to the technical field of mutual inductor harmonic current detection, and provides a mutual inductor harmonic current detection method and system. The mutual inductor harmonic current detection method comprises the following steps: carrying out fast Fourier transform on a preprocessed mutual inductor current signal, and extracting a harmonic current signal; extracting harmonic current signal local features of a short time scale from the harmonic current signal, and then capturing long-term time dependence of the harmonic current signal local features of the short time scale to obtain harmonic current signal features; variational mode decomposition is carried out on the harmonic current signal characteristics to obtain the amplitude of each harmonic, the proportion of the amplitude of each harmonic to the current amplitude of the rated current of the transformer is calculated, and error correction is carried out on each harmonic in combination with the pre-constructed mathematical relationship among the harmonic number, the current amplitude proportion and a correction coefficient to obtain the harmonic current. The total harmonic distortion rate is calculated according to the harmonic after error correction, harmonic current detection can be rapidly and accurately achieved, and the influence of noise interference on detection precision is reduced.

The invention relates to the technical field of power system protection, and discloses a direct-current line bipolar short-circuit fault protection method based on harmonic impedance, which comprises the following steps: measuring a voltage waveform signal and a current waveform signal of a direct-current line protection position in real time; processing the voltage waveform signal and the current waveform signal by adopting short-time Fourier transform, and extracting a high-frequency voltage component and a high-frequency current component of a specific harmonic order; calculating a module value and a phase angle of the high-frequency voltage component and a module value and a phase angle of the high-frequency current component, and obtaining harmonic impedance through voltage division calculation; the fault position is determined according to the harmonic impedance change of each line before and after the fault occurs; the fault position is determined through the harmonic impedance change of each line before and after the fault occurs, and a rapid, reliable and economical protection scheme is provided for the bipolar short-circuit fault of the direct-current line.

The application discloses a kind of electric quantity use situation prompt and safety early warning monitoring method and system, comprising: acquisition low-frequency metering and high-frequency harmonic channel data, generate analysis window signal;Parameterized spectrum estimation obtains harmonic order, frequency, amplitude, phase and filters effective component;Rotary harmonic state sequence is constructed, and total harmonic distortion and sub-band energy are calculated;With low-frequency data and harmonic index as exogenous input, structured state space model is constructed, and multiple-step prediction and hidden state are output;Gated fusion state sequence and hidden state, limit parameter search range;Construct joint optimization target, end-to-end training and solidify model structure and parameter;Model deployment generates electric quantity and harmonic trend prediction, trigger prompt and early warning and output to visual terminal.The application realizes the accurate prediction of electric quantity use trend and harmonic index and over-limit safety early warning by fusing multi-channel sampling, harmonic state modeling and structured state space prediction.

The invention discloses an electric quantity use condition prompting and safety early warning monitoring method and system, and the method comprises the steps: collecting low-frequency metering and high-frequency harmonic channel data, and generating an analysis window signal; performing parametric spectrum estimation to obtain harmonic order, frequency, amplitude and phase, and screening effective components; constructing a rotary type harmonic state sequence, and calculating total harmonic distortion and zoning energy; low-frequency data and harmonic indexes are used as exogenous input, a structured state space model is constructed, and multi-step prediction and hidden states are output; gating a fusion state sequence and a hidden state, and limiting a parameter search range; constructing a joint optimization target, performing end-to-end training, and solidifying a model structure and parameters; and the deployment model generates electric quantity and harmonic trend prediction, triggers prompt and early warning, and outputs the information to a visual terminal. According to the invention, through fusion of multi-channel sampling, harmonic state modeling and structured state space prediction, accurate prediction and over-limit safety early warning of an electric quantity use trend and a harmonic index are realized.

This application discloses a method for extracting the DC component of an AC signal, comprising: acquiring the AC signal to be processed and its fundamental angular frequency; sequentially performing low-frequency harmonic elimination processing on the AC signal according to the fundamental angular frequency in descending order of harmonic order, wherein each low-frequency harmonic elimination process is configured to: eliminate the current target low-frequency harmonic, while amplifying the high-frequency noise and higher-order harmonics in the AC signal that have not been eliminated, causing the high-frequency noise and higher-order harmonics to trigger amplitude limiting; after completing a preset number of low-frequency harmonic elimination processes, filtering the obtained signal to extract the target DC component from the AC signal; wherein the amplitude limiting value is set to be significantly higher than the amplitude of the target DC component in the AC signal, so that the amplitude of the high-frequency noise and higher-order harmonics after amplitude limiting is far away from the amplitude of the target DC component. This method can achieve fast and accurate extraction of the target DC component.

A drive motor and a retarder in a powertrain meet a condition that a harmonic order of the drive motor is the same as a quantity of gear teeth of an input shaft gear in the retarder such that a frequency of an electromagnetic noise harmonic generated by the drive motor is the same as a frequency of a noise harmonic generated by the retarder. When the drive motor and the retarder are coupled using a connection structure, a phase of the electromagnetic noise harmonic generated by the drive motor differs from a phase of the noise harmonic generated by the retarder by a set angle.

The invention relates to the technical field of power systems, in particular to a harmonic source dynamic monitoring and responsibility distribution platform and method, and the platform comprises the following steps: a real-time monitoring module, a harmonic source positioning module, a responsibility distribution module, an alarm and event recording module and a data management and analysis module. According to the system, the time domain sampling density of high-frequency harmonics is remarkably improved, the sampling rate of 20 kHz enables the number of sampling points in a single period to be increased to 6.67 points from 1.67 points in the sampling process of 5 kHz, the problem of waveform distortion caused by time domain signal discretization is effectively solved, the actually measured harmonic amplitude error is converged to be within + / -5% from + / -30%, the phase error is reduced to be negligible, and the method has the advantages that the method is simple and easy to implement. The method can automatically detect and correct error frequency components in a frequency spectrum, and when 18kHz harmonic waves are aliasing to 2kHz due to undersampling, the algorithm matches with a harmonic wave prior model through amplitude correlation analysis, and redistributes energy to real frequency points, so that the identification accuracy of harmonic wave times is improved, and a real and reliable data basis is provided for subsequent analysis.

The present application belongs to the field of harmonic analysis, and provides a harmonic disturbance analysis method and system based on harmonic active power distribution, which carries out pretreatment on the obtained three-phase voltage and current data of each node, separates the fundamental wave and harmonic components through orthogonal transformation, calculates the instantaneous harmonic active power of each node under the reference working condition, calculates and counts the average harmonic active power under the steady state, calculates the harmonic active power of each node under the working condition of single or multiple harmonic sources, carries out difference processing on the harmonic active power under the working condition and the harmonic active power under the reference working condition, obtains the node harmonic active power increment distribution of the to-be-tested working condition relative to the reference working condition, and preliminarily determines the harmonic source position; according to the positive and negative directions, amplitude size and change law along the topology path of the harmonic active power of each node, a harmonic active power distribution propagation heat map is drawn, and the dominant harmonic order, the frequency prone to harmonic amplification and the harmonic disturbance sensitive area are identified. The present application realizes accurate analysis of harmonics.

Embodiments of the present application disclose a pre-processing matrix multiplexing method and device, electronic equipment and a storage medium; the method comprises: obtaining simulation parameters of a to-be-simulated circuit, and generating frequencies corresponding to each harmonic according to a fundamental frequency and a maximum harmonic order in the simulation parameters; dividing the frequencies corresponding to each harmonic into a plurality of frequency groups according to the size of the frequencies corresponding to each harmonic; determining representative frequencies of each frequency group, and constructing a pre-processing matrix corresponding to each frequency group based on the representative frequencies.

This invention discloses a broadband oscillation assessment method, apparatus, and device. By applying harmonic voltage and current sources, it calculates the node harmonic response values ​​at different harmonic orders, plots node harmonic response curves based on these values, and determines whether a node has a resonance risk based on the curves. This method does not rely on the accuracy of system modeling and does not require system disconnection or shutdown. Compared to pre-assessment methods, it is more accurate and more flexible than on-site protection assessment methods, solving the technical problems of poor accuracy and flexibility in existing broadband oscillation assessment methods.

The invention discloses a motor vibration noise suppression method and device, and the method comprises the steps: inputting a direct-axis target current and a quadrature-axis target current into a PI controller, and obtaining a direct-axis DC voltage and a quadrature-axis DC voltage; an R controller is added into a PI controller, and in the parameter adjusting process of the PIR controller, the vibration acceleration and harmonic component of each current harmonic order are recorded, and direct-axis alternating voltage and quadrature-axis alternating voltage are extracted; determining a direct-axis compensation voltage and a quadrature-axis compensation voltage; based on the sum value of the direct-axis direct-current voltage and the direct-axis compensation voltage; calculating the sum value of the quadrature-axis DC voltage and the quadrature-axis compensation voltage; and suppressing the vibration noise of the motor according to the final direct-axis voltage and the final quadrature-axis voltage. The harmonic voltage amplitude is extracted through closed-loop control, then the harmonic voltage phase (namely a sinusoidal signal) is calibrated through open-loop control, and by means of the method combining closed-loop and open-loop harmonic injection, the stability of the system is high, and instability caused by improper parameters is not likely to happen.

The invention relates to a vibration measurement method of a scanning type laser Doppler vibration meter capable of avoiding harmonic interference, which comprises the following steps of: S1, arranging a reference point on a scanning path of the vibration meter, scanning the vibration of the reference point so as to acquire a rough measurement vibration signal of a measured object, and carrying out segmented filtering processing; s2, determining the fundamental frequency f and the maximum harmonic order nmax of the measured object according to the filtered roughly measured vibration signal, and calculating the fundamental frequency f and the distribution range of each order of harmonic frequency; s3, acquiring a scanning frequency fs, judging whether fs is overlapped with the harmonic frequency of each order or not, if yes, adding an offset delta f on the basis of the scanning frequency fs, and returning to the step S3; if not, the scanning frequency fs serves as the actual scanning frequency fs', and then the step S4 is executed, and S4, the actual scanning frequency fs' is adopted to scan the measured object to obtain vibration signal data, the scanning frequency and all harmonic frequencies are not overlapped, and then harmonic interference is avoided.

The invention relates to a fractional slot concentrated winding permanent magnet motor demagnetization space distribution self-adaptive compensation method, which comprises the steps of collecting a motor driving physical quantity, calculating a permanent magnet flux linkage estimation value based on the motor driving physical quantity, generating a flux linkage residual error sequence, performing frequency domain analysis on the flux linkage residual error sequence, and obtaining a target fault harmonic order. An analytical model of the demagnetization area is constructed, and an equivalent flux linkage loss function is obtained; performing Fourier series expansion on the equivalent flux linkage loss function to obtain a harmonic complex coefficient set for constructing an error function for demagnetization space distribution parameters, and performing iterative solution on the demagnetization space distribution parameters by using a parameter inversion model by taking the error function as a target to obtain an identification result; and constructing an equivalent permanent magnet flux linkage function under the current rotor electrical angle by using an identification result to correct a d-axis current instruction, setting a compensation voltage vector orthogonal to a demagnetization flux linkage harmonic wave, and superposing the compensation voltage vector to a PI output end in a feedforward form to generate a final d-q voltage instruction.

The invention relates to the technical field of online monitoring of transformers, in particular to an online monitoring operation method of a three-phase low-voltage current transformer. Comprising the following steps: acquiring secondary current of a three-phase low-voltage current transformer, and calculating secondary zero-sequence current of the secondary side of the three-phase low-voltage current transformer; the primary zero-sequence current of the primary side of the three-phase low-voltage current transformer is obtained through the zero-sequence current transformer, and the standard secondary zero-sequence current of the secondary side of the three-phase low-voltage current transformer is calculated. The harmonic synthesis error of the three-phase low-voltage current transformer under each harmonic is finally calculated through the ratio of the secondary zero-sequence current to the standard secondary zero-sequence current, a fault decision factor is calculated according to the weight coefficient of each harmonic synthesis error, and when the fault decision factor is greater than a corresponding fault threshold, the three-phase low-voltage current transformer is judged to be in a fault state. And determining that the three-phase low-voltage current transformer has a fault. On-line monitoring of the three-phase low-voltage current transformer can be realized through the fault judgment factor, and the accuracy of fault judgment is improved.

This application discloses a method and system for adjusting the capacity of a distribution transformer based on adaptive linear neurons, relating to the field of electrical equipment and power system automation. The method includes: inputting the secondary current to an adaptive linear neuron filter to filter out harmonic components corresponding to harmonic orders in the secondary current, and outputting the fundamental frequency component; the adaptive linear neuron filter constructs a corresponding input vector based on the harmonic order and the fundamental frequency component, the input vector including the sine and cosine components of the harmonic order, and the sine and cosine components of the fundamental frequency component; calculating the amplitude of the fundamental frequency component, comparing the amplitude of the fundamental frequency component with a preset capacity adjustment threshold, generating a switching control signal for the IGBT, and controlling the switching state of the distribution transformer windings according to the switching control signal. This application solves the technical problem that current methods using secondary current as the capacity adjustment criterion result in inaccurate estimation of the transformer's fundamental frequency capacity, leading to the transformer entering a high-capacity state prematurely or a low-capacity state too late.

In a method for reducing harmonics in a drive system (10) of an electrically powered vehicle, at least one sensor signal containing harmonics of the rotor frequency (f) is used. R ) in a harmonic order (n) to be reduced, is detected. An amplitude (A) and a phase (φ) of the harmonic of a single order (n) to be reduced are derived from the sensor signal (S). M ) is extracted. A reduction signal (S) is generated. R ) with the frequency of the harmonic of the order (n) to be reduced based on the extracted amplitude (A) and phase (φ) and the reduction signal (S R ) becomes a motor voltage signal (U M The values ​​are added such that the amplitude (A) of the harmonic of the order (n) to be reduced is reduced. A control unit (24) of the drive system (10) is designed to execute the procedure.

This invention relates to an adaptive time-frequency joint filtering method for electrostatic data from solid rocket motor exhaust. The method includes the following steps: constructing a main channel filtering algorithm to suppress the fundamental combustion oscillation, employing an adaptive IIR notch filter, with the core frequency detected by a real-time FFT algorithm and the bandwidth dynamically adjusted according to the combustion state; constructing an auxiliary channel to suppress harmonics, consisting of multiple parallel notch filters, each corresponding to a harmonic frequency, with the harmonic order adaptively determined based on the fundamental attenuation; addressing the phase distortion problem of traditional IIR filters by using forward-backward filtering to offset phase shift; particle pulse detection is the core of solid rocket motor exhaust electrostatic signal processing, aiming to accurately identify transient pulses (1-5 μs) generated by Al2O3 particle collisions; this invention uses a wavelet domain adaptive algorithm based on multi-scale noise separation, a time-varying threshold mechanism, and the SURE optimization criterion to suppress combustion oscillations and noise in the exhaust electrostatic signal while preserving particle pulse information.

The invention provides an ultrasonic directional sound production system and method based on multi-order fundamental frequency multiplication and compensation, and the system comprises an audible sound receiving module which is used for obtaining an audible sound fundamental frequency; the multi-order ultrasonic fundamental frequency generation module is used for generating a multi-order ultrasonic fundamental frequency signal; the audible sound fundamental frequency multiplication module is used for obtaining frequency multiplication orders of audible sound fundamental frequencies of different frequency bands and carrying out frequency multiplication on the audible sound fundamental frequencies of the different frequency bands according to the corresponding frequency multiplication orders to obtain frequency multiplication signals; the modulation module is used for receiving the frequency multiplication signal and modulating the frequency multiplication signal into a fundamental frequency signal so as to obtain a multi-band composite modulation ultrasonic signal; the compensation calibration module is used for performing signal compensation on the multi-band composite modulation ultrasonic signal to obtain a compensated composite modulation ultrasonic signal; and the transducer module is used for receiving the compensated composite modulation ultrasonic signal to form a sound field.

The invention relates to the technical field of signal processing, in particular to a nuclear power equipment signal processing method based on dynamic variational mode decomposition, which comprises the following steps of: acquiring a vibration signal of a nuclear power equipment centrifugal pump rolling bearing, initializing a dynamic decomposition parameter, and acquiring a dynamic decomposition parameter; setting a maximum decomposition layer number, a theoretical value of a fault characteristic frequency pair and a harmonic order; fault impact share indexes corresponding to the alpha values are calculated, and alpha coarse corresponding to the FIS maximum value is screened; updating an optimal value alpha mind, iteratively updating a modal component through an augmented Lagrange function, updating a modal function uk in a frequency domain, and updating uk to minimize a bandwidth item in a target function; fourier transform is carried out on the envelope signal A (t), FIS under each IMF envelope spectrum is calculated, a plurality of IMFs are obtained through decomposition, FIS is calculated, the IMF with the maximum FIS is selected as final output, and fault features in the signal are obtained. According to the invention, the problems of difficult fault feature extraction and poor signal noise reduction effect of the rolling bearing non-stationary vibration signal of the centrifugal pump of the nuclear power device can be solved.

The invention discloses a PBB adaptive step length optimization harmonic current suppression method based on a multi-rotating coordinate system, and the method specifically comprises the steps: building a permanent magnet synchronous linear motor model, obtaining a phase current signal, and obtaining a dq-axis current through coordinate transformation; establishing an independent rotating coordinate system for a target harmonic order, constructing a self-adaptive step length low-pass filter based on a parameterized PBB algorithm, and outputting a harmonic current estimated value; constructing an optimal harmonic reference current solving model, and performing iterative optimization through a PBB algorithm to obtain an optimal harmonic reference current; and taking the error between the optimal harmonic reference current and the harmonic current estimation value as the input of a PR controller, generating a harmonic compensation voltage, and injecting the harmonic compensation voltage into a feed-forward channel to compensate the harmonic current. According to the invention, the harmonic current of the permanent magnet synchronous linear motor is rapidly and effectively suppressed by adopting a harmonic injection integrated scheme of a multi-rotation reference coordinate system, an ASS-LPF optimization algorithm and a PBB optimization algorithm.

This application relates to isolated capacitive power transfer. A method and apparatus for providing isolated power transfer to a low power load across a capacitor of a series resonant circuit is shown. The method includes comparing an output voltage received via a feedback loop to a desired output voltage. In response to determining that the output voltage is not equal to the desired output voltage, the method determines a sub-harmonic order of a resonant frequency of the series resonant circuit to use as a switching frequency, and switches the series resonant circuit substantially at the determined sub-harmonic order of the resonant frequency.

The invention relates to the technical field of power systems, in particular to an electricity larceny identification method and system. The method comprises the steps of calculating to-be-detected user side fundamental wave complex impedance; harmonic signals with different preset frequencies are injected, and corresponding harmonic complex impedance is synchronously acquired and calculated. And taking the harmonic order as an abscissa and the harmonic and fundamental wave impedance amplitude deviation ratio as an ordinate, and taking a quadratic term coefficient absolute value through quadratic polynomial fitting to obtain the harmonic amplitude attenuation variation degree. Counting the consistency and inconsistency times of the impedance phase difference symbols of the fundamental wave and each harmonic wave, and obtaining a phase symbol consistency coefficient according to the difference value and the total harmonic number; and according to the phase symbol consistency coefficient, the amplitude attenuation variation degree, the frequency trend slope, the standard deviation of the phase difference between the fundamental wave complex impedance and the harmonic complex impedance corresponding to all the preset frequencies, and the harmonic frequency corresponding to each preset frequency, constructing an electricity larceny identification feature vector, thereby obtaining an electricity larceny identification result. According to the invention, the electricity stealing identification precision is effectively improved.