53 results about "Harmonic energy" patented technology

The invention relates to the technical field of maglev motor dynamics and control, and discloses a bearingless asynchronous motor multi-frequency harmonic vibration cooperative suppression method, which comprises the following steps: acquiring radial displacement signals and mechanical angular velocity of a rotor in an x axis and a y axis under a stator fixed coordinate system, and stacking double-axis displacement signals into an observation vector; calculating a weighting coefficient of the normalized residual error through a Huber robust cost function, and outputting the amplitude, the phase and the confidence of each order of harmonic wave; estimating the total disturbance of the system by using a linear extended state observer with harmonic energy injection, wherein the total disturbance is obtained by weighted summation according to the confidence, order and mechanical angular velocity of each order of harmonic; calculating a feedback control force according to the total disturbance estimated value, and superposing the feedforward compensation force and the feedback control force to generate a total suspension force instruction; and according to the total suspension force instruction, inversely calculating a suspension winding current reference value and outputting a control instruction. According to the invention, a mutually complementary cooperative suppression mechanism is formed, and the suppression precision of multi-frequency vibration is improved.

The invention relates to the technical field of electrical engineering and intelligent fault diagnosis, and discloses a water pump motor fault diagnosis method and system based on current harmonic characteristics, and the method comprises the steps: collecting stator current, rotating speed and load signals; generating an alpha-beta current component through Clark transformation, constructing an analytic signal, extracting an instantaneous phase, and calculating an instantaneous frequency; a mapping relation is established in combination with the rotating speed, and the current signals are resampled to eliminate frequency dispersion; obtaining a high-resolution harmonic energy distribution diagram by adopting multi-scale synchronous compression wavelet transform; and extracting an energy concentration ratio, a peak offset and a bandwidth expansion coefficient in the characteristic frequency band, inputting the energy concentration ratio, the peak offset and the bandwidth expansion coefficient into the pre-trained multi-layer perceptron classifier, and outputting a fault type. According to the method, through high-precision time-frequency focusing and multi-dimensional feature fusion, the fault recognition accuracy and robustness are remarkably improved, and online diagnosis of multiple typical faults can be achieved only through current signals.

The invention relates to the technical field of power monitoring, in particular to an online monitoring method and system for a power control cabinet. The method comprises the following steps: acquiring a time domain signal, tracking a fundamental wave frequency, adjusting a sampling window, and performing Fourier transform to obtain a harmonic amplitude and a phase; harmonic waves are divided into harmonic wave correlation groups according to association rules, harmonic wave phase consistency coefficients are calculated to weight the total energy in the groups, and weighted harmonic wave energy is obtained; total inter-harmonic energy is calculated, and an inter-harmonic structure factor is obtained based on the spectral entropy. And acquiring a real-time load rate and a change rate, and calculating a synchronous change coefficient and a load factor. And summing the weighted harmonic energy and the corrected inter-harmonic energy to obtain total distortion energy, and obtaining a comprehensive distortion index according to the total distortion energy. According to the scheme, the structured inter-harmonics possibly caused by the early failure of the equipment can be found earlier, and the requirements of early warning and predictive maintenance are met.

The invention discloses a power distribution network reliability intelligent analysis method and analysis system, particularly relates to the technical field of power system fault detection, and is used for solving the problems of misjudgment and missed judgment caused by fault feature weakening and harmonic interference in a bidirectional power flow scene in an existing method. The method comprises the following steps: firstly, synchronously collecting fundamental wave and harmonic components of nodes of a power distribution network, extracting a current amplitude change rate and a phase offset by adopting time-frequency domain conjoint analysis, and generating dynamic distribution characteristics by combining harmonic energy clustering; identifying high-frequency interference components in a bidirectional power flow mode by quantizing a phase deviation direction and harmonic energy aggregation characteristics; based on a harmonic frequency band coupling effect and a current dynamic association relationship, an adaptive detection threshold function is constructed, and accurate separation of fault features is realized; and finally, combining a real-time fault judgment result with historical repair data to generate a reliability evaluation parameter. And the sensitivity of fault detection and the rationality of reliability evaluation in a complex operation environment are remarkably improved.

The invention discloses an up-mixing harmonic energy communication system and method based on direct-mixing intermodulation signal suppression. The communication system includes a receive antenna and an integrated rectified transmitter. The integrated rectified transmitter includes a first branch and a second branch. The invention provides an integrated rectification transmitter with a double-branch structure, an IM2 modulation module is arranged at the tail end of a first branch, and a 90-degree phase shift network is arranged at the head end of a second branch, so that uncontrollable IMD3 signals generated in the first branch and the second branch have a phase difference of 180 degrees and are mutually counteracted; in this way, only the upmixing IMU3 signal which can be controllably and accurately modulated in the first branch is reserved in the uploaded backscattering signal, and more accurate and reliable wireless energy cooperative information transmission is achieved. According to the invention, the frequency of the IM3 signal for communication is close to that of the input dual-tone signal, so that multiplexing can be realized by only needing a small bandwidth in the design of the receiving and transmitting antenna.

The invention relates to the technical field of motor control in the intelligent power grid industry, and discloses a space vector control method for a twelve-phase permanent magnet synchronous motor flywheel energy storage system, a control circuit of the flywheel energy storage system relates to power electronic components such as various semiconductor field-effect tubes, and the space vector control method is used for high-precision control of a motor. Comprising the steps of S1, twelve-phase space vector decoupling fault-tolerant control, S2, high-order harmonic energy recovery closed loop, S3, quantum annealing parameter optimization layer, S4, flux linkage adaptive observer network construction and S5, 18-dimensional switching vector table construction. According to the scheme, through multi-reference coordinate system transformation and a redundant phase reconstruction algorithm, rapid fault-tolerant response of the twelve-phase motor during a single-phase or two-phase fault is realized, a current path is dynamically recombined during the fault, a negative-sequence current compensation ring is combined, torque ripple is effectively suppressed, and the reliability of the motor is improved under a high-speed charging and discharging working condition. The harmonic distortion rate is detected in real time through the sliding window FFT, the bandwidth of the controller is adjusted, and the problem that the dynamic response of a traditional fault-tolerant strategy is insufficient is solved.

The invention relates to the technical field of fault prediction, in particular to a robot finger test method and system based on a robot, and the method comprises the following steps: synchronously collecting a phase current time sequence signal and an injected ultra-wideband pulse reflection signal at a servo motor drive output end of a robot finger, carrying out the alignment according to a collection timestamp, and carrying out the detection of the phase current time sequence signal; a pair of original timing electrical signals is generated. According to the invention, a phase current time sequence signal reflecting mechanical load characteristics and an ultra wide band pulse reflection signal actively detecting electrical link integrity are synchronously acquired at a driving output end of a servo motor, a multi-dimensional and information-complementary original electrical signal pair is constructed, and a phase current signal is processed to separate current ripples. And transmission harmonic energy distribution directly related to mechanical motions such as meshing of a reduction gear and rotation of a motor is extracted, so that non-intrusive quantitative evaluation of the health state of the internal transmission system of the robot finger is realized.

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.

The invention discloses a magnetic particle imaging method based on multi-harmonic energy-full width at half maximum combined weighting, which comprises the following steps: acquiring point spread functions of a plurality of harmonic waves with different frequencies of magnetic nanoparticles, and constructing a corresponding system matrix; measuring a reference sample which does not contain the magnetic nanoparticles, and obtaining a plurality of noise matrixes corresponding to harmonic waves with different frequencies; measuring the sample to be measured, and obtaining magnetization response voltage vectors of a plurality of harmonic waves with different frequencies; respectively calculating an energy two-norm of a system matrix, an energy two-norm of a noise matrix and a full width at half maximum of a point spread function of the system matrix and the noise matrix; splicing the magnetization response voltage signals of each harmonic system matrix to form a total system matrix and a total measurement signal vector; calculating a weight factor of each harmonic wave and forming a weight matrix; and constructing a solution equation of the particle concentration distribution of the sample to be detected, and carrying out iterative solution on the solution equation to obtain a particle concentration distribution image of the sample to be detected. According to the invention, efficient utilization of multi-harmonic information is realized.

The application discloses a bearing composite fault diagnosis method and system, first, a bearing composite fault vibration observation signal is acquired; then, the observation signal is subjected to short-time Fourier transform and cepstrum threshold processing, two-dimensional time-frequency mask blind source separation, inverse short-time Fourier transform is performed on the obtained time-frequency domain separation signal and band-pass filtering is performed, independent time domain estimation signals are obtained; then, the estimation signals are subjected to Hilbert envelope demodulation and Fourier transform, envelope spectra of the filtered signals are obtained; finally, each order characteristic frequency band of a target fault is searched, a harmonic energy impact index is constructed, and an impact pulse value is calculated; the calculated impact pulse value is compared with a threshold value, and whether the bearing has a target type fault is diagnosed.

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 invention discloses a cast-in-place concrete structure full-period maintenance system combined with cloud gateway data transmission, and relates to the technical field of building construction, the cast-in-place concrete structure full-period maintenance system comprises a three-field coupling modeling module, a cavity resonance recognition module, a spraying posture surveying and mapping module, an anti-harmonic energy regulation and control module and a self-adaptive spraying control module, in the nighttime temperature drop stage, a fluid, bubble and pipe wall three-field coupling model is constructed, a backflow wave path, bubble compression response and pipe wall elastic reflection characteristics are extracted through time domain decomposition, and dynamic baseline data are generated. Through coupling modeling and resonance recognition, spraying deviation monitoring and blind area prediction are achieved, a spraying posture closed-loop adjusting mechanism is constructed in combination with anti-resonance injection and self-adaptive control, the maintenance uniformity and reliability are improved, the crack risk is reduced, and the service life of the structure is prolonged.

The invention provides a nondestructive detection method and device for ferromagnetic pipeline defects, and belongs to the field of pipeline detection.The method comprises the steps that voltage signals are obtained, and the voltage signals are obtained by converting capacitance change signals continuously collected by bipolar plate capacitors when a ferromagnetic pipeline and upper and lower semi-arc bipolar plate capacitors move relatively at a constant speed in the axial direction; extracting time domain features and frequency domain features of the voltage signals; according to the voltage signals and extracted features, determining defect types and defect positions, the extracted features including time domain features and frequency domain features; the time domain feature comprises a signal standard deviation, a variable coefficient and a local extreme point density, and the frequency domain feature comprises a dominant frequency component and a harmonic energy ratio. According to the method, by utilizing the physical characteristics that the dielectric constants of the ferromagnetic pipeline are different in different states with or without defects, the defects penetrating into the component can be detected, interference of electromagnetic noise in various environments is effectively avoided, the accuracy of the detection result is ensured, point-by-point scanning is not needed, and the detection efficiency is higher.

The invention provides a Chinese lute string fundamental frequency determination method and system, and the method comprises the steps: carrying out the time-frequency conversion of an audio signal, extracting a spectrum peak value, carrying out the energy weighting of the peak value according to a preset harmonic attenuation function, setting a candidate fundamental frequency set, constructing a preliminary harmonic cluster based on an initial non-harmonic coefficient, selecting a cluster with the highest energy, and calculating a real-time non-harmonic coefficient; and reconstructing candidate harmonic clusters according to the coefficient, and evaluating each harmonic cluster from two aspects of harmonic energy continuity and time domain correlation: calculating the sum of harmonic energy and combining with missing penalty to obtain an energy continuity score, and obtaining a time correlation score through a time cross-correlation mean value of fundamental frequency and each harmonic component energy envelope; and a comprehensive score is obtained after weighted summation.

This application relates to a traction control system method, device, controller, and medium. The method includes: during the starting process of a target vehicle, acquiring the wheel speed, tire pressure, vehicle deceleration, and torque output of the target vehicle within the current control cycle; acquiring the fundamental oscillation frequency based on the tire pressure, vehicle deceleration, and road surface adhesion coefficient, and acquiring the wheel phase spectrum signal based on the wheel speed; acquiring the harmonic frequencies and harmonic energies of multiple harmonics based on the fundamental oscillation frequency and the wheel phase spectrum signal, and obtaining the harmonic energy ratio; if the harmonic energy ratio or the vehicle speed within the current control cycle meets preset conditions, acquiring the torque output control gain coefficient based on the harmonic energy ratio, vehicle speed, and target harmonic frequency; and generating a torque output control command based on the torque output control gain coefficient and torque output data. This method can improve the suppression effect of vibration divergence.

The invention discloses a concrete pouring process monitoring method and system based on multi-source data, relates to the field of intelligent monitoring, and particularly relates to the following steps: carrying out semantic segmentation and positioning on a pouring area and a vibrating rod by using a visible light video, and constructing an accurate space mask; meanwhile, the key vibration frequency is extracted from the vibration signal. On the basis, a vibration phase-locked thermal imaging technology is applied, the vibration frequency is used as a phase-locked reference, and harmonic energy transfer gain characteristics with the same frequency as vibration are extracted from a thermal infrared image sequence. And then temperature field uniformity evaluation is carried out by fusing the spatial position and the energy transfer characteristics, so that quantitative visualization of the concrete pouring quality is realized, and the technical problem that whether quality defects such as voids and pitted surfaces exist in the concrete or not cannot be judged only by means of surface visual characteristics is effectively solved.

The invention relates to an audio conversion method and device, electronic equipment and a storage medium. The audio conversion method comprises the following steps: extracting audio features and timbre features of a target object audio and a reference audio, and mapping the timbre features of the reference audio in the audio features to obtain mapped audio features; obtaining harmonic energy of the target object audio based on a fundamental frequency feature in the target object audio and a loudness feature of the reference audio; and based on the mapped audio feature, the loudness feature and the harmonic energy, performing audio conversion on the target object audio to obtain a target audio, keeping the harmonic energy and loudness of the target object audio in the target audio, and replacing the tone feature with the mapped tone feature. According to the invention, the audio conversion quality is improved.

The invention relates to the field of rotary transformer fault detection, in particular to a rotary transformer output signal-based multi-parameter analysis and fault diagnosis method, which comprises the following steps of: acquiring a target output signal of a diagnosis analysis target; determining whether to perform harmonic information processing or electric energy information processing according to the fluctuation amplitude index; when harmonic information processing is carried out, whether harmonic component analysis or harmonic energy analysis is carried out is determined according to the fluctuation characteristic reproduction index, recommended fault positioning information is determined according to the dominant frequency state, and a fault radiation index is determined according to the amplitude corresponding to each frequency component corresponding to the target identification spectrum; and when electric energy information processing is carried out, whether recommended fault positioning information is sent to a user is determined based on the direct-current resistance parameters and the insulation resistance parameters. The rotary transformer and the application equipment thereof are effectively monitored based on the output signal of the rotary transformer, the requirement for external monitoring is lowered, and the data analysis efficiency in the fault monitoring process is improved.

The application provides a kind of energy storage converter efficiency dynamic high-precision synchronous test method, belongs to energy storage technical field, specifically is through fusion spectrum analysis and phase synchronous adjustment, real-time compensation current distortion and correct power factor, to obtain pure fundamental signal for energy integration, and then utilize wavelet transform decomposition harmonic energy and construct energy flow path model, again through adaptive correction algorithm optimization path parameters, finally under dynamic operation condition, realized to energy storage converter overall efficiency high-precision, synchronization test.

The invention provides an audio processing method and device, equipment, a medium and a program product, which are applied to various scenes such as cloud technology, artificial intelligence, map field, intelligent traffic and auxiliary driving, and the method comprises the following steps: obtaining a target audio frame and a target fundamental tone frequency of the target audio frame; the target audio frame is obtained through wind noise suppression processing; determining a target peak-valley energy parameter according to the harmonic energy of at least two target rear-segment harmonics corresponding to the target fundamental tone frequency; determining an energy compensation parameter corresponding to the target fundamental tone frequency and the target peak valley energy parameter based on preset mapping information; the energy compensation parameter is obtained based on harmonic energy statistical processing of harmonic waves in a normal audio frame; and determining a corrected audio frame corresponding to the target audio frame according to the energy compensation parameter and the harmonic energy of the at least two target rear-segment harmonics. By using the method, the restored audio frame can be restored to a relatively normal level, so that the definition and the understandability of a final output sound source signal are improved.

The invention provides a method and a device for detecting the strength of a filling body based on sound wave spectrum analysis, relates to the technical field of mine filling materials, and aims to evaluate the strength by analyzing complete spectrum characteristics of sound waves after the sound waves pass through the filling body. Specifically, when sound waves are propagated in a filling body, parameters such as consolidation degree, compactness and internal defects of the filling body can generate unique influence on frequency, amplitude and phase of sound wave signals, so that the frequency spectrum of the sound wave signals is correspondingly changed. According to the method, the acoustic signals are collected and subjected to spectral analysis such as Fourier transform, a plurality of characteristic parameters including main frequency offset, harmonic energy change and spectrum peak amplitude can be extracted, and a quantitative model between the multiple parameters and the strength of the filling body is established. According to the method, the internal structure and the mechanical property of the filling body can be reflected more comprehensively and accurately, and a new technical scheme which is high in precision, lossless and suitable for on-site rapid detection is provided for quality control of the mine filling body.

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 invention provides an electric shovel transformer abnormity determination method, device and equipment and a storage medium, and the method comprises the steps: collecting the original voiceprint data and cable current waveform of an electric shovel transformer through a voiceprint monitoring system; preprocessing and framing are carried out on the original voiceprint data, a fundamental wave phase is tracked based on the original voiceprint data to generate a coefficient of a wave trap, fundamental waves and harmonic waves in frame voiceprints are suppressed and distinguished through the wave trap, and a reduced voiceprint signal is obtained; predicting and offsetting residual harmonic energy in the reduced voiceprint signal by using an adaptive filter and taking a cable current waveform as a reference to obtain a primary noise reduction signal; performing feature extraction based on the primary noise reduction signal to obtain a feature vector; and identifying the current working condition of the electric shovel transformer through the lightweight decision model, performing normalization processing on the feature vector through the mean variance weight table corresponding to the current working condition, and inputting the normalized vector into the transformer normal voiceprint Gaussian mixture model corresponding to the current working condition to obtain a judgment result of whether the transformer is abnormal or not.

This invention provides a method and system for determining the fundamental frequency of a pipa (a traditional Chinese stringed instrument). The method involves performing time-frequency transformation on an audio signal to extract spectral peaks, weighting the peak energy according to a preset harmonic attenuation function, and setting a candidate fundamental frequency set. First, an initial harmonic cluster is constructed based on initial anharmonic coefficients. The cluster with the highest energy is selected to calculate real-time anharmonic coefficients, and then these coefficients are used to reconstruct the candidate harmonic clusters. Each harmonic cluster is evaluated from two aspects: harmonic energy continuity and time-domain correlation. The total harmonic energy is calculated and combined with a missing component penalty to obtain an energy continuity score. Simultaneously, the time correlation score is obtained by calculating the mean time cross-correlation between the fundamental frequency and the energy envelopes of each harmonic component. A weighted sum is then used to obtain a comprehensive score.

The invention discloses a coverage consistency measurement and optimization method and system based on harmonic circularity. According to the method, equiangular sampling is carried out on azimuth irradiance envelope of a light-emitting array on a horizontal plane, Fourier decomposition is carried out on sampled data, and Fourier coefficients of all orders are obtained; and calculating the harmonic energy of each order and the normalized value thereof, and accumulating the normalized harmonic energy on a preset low-order harmonic set so as to calculate the harmonic circularity. And comparing the harmonic roundness with a preset threshold, if the harmonic roundness does not reach the standard, adjusting the geometric layout and / or power counterweight of the array according to a rule of reducing low-order harmonic energy, and performing iterative optimization until the standard is reached, and finally taking an optimization parameter as an acceptance and maintenance reference. The corresponding system comprises an irradiance envelope acquisition module, a frequency spectrum conversion module, a harmonic calculation module, a harmonic roundness calculation module, a threshold determination module, a low-order suppression optimization module and a calibration self-calibration module. According to the invention, quantifiable suppression and long-term maintenance of coverage non-uniformity are realized.

The application relates to the technical field of electrical engineering and intelligent fault diagnosis, and discloses a water pump motor fault diagnosis method and system based on current harmonic characteristics, which comprises the following steps: collecting stator current, rotating speed and load signals; generating alpha beta current components through Clark transformation, constructing analytical signals, extracting instantaneous phases, and calculating instantaneous frequencies; combining the rotating speed to establish a mapping relationship, resampling the current signals to eliminate frequency dispersion; adopting multi-scale synchronous compression wavelet transformation to obtain a high-resolution harmonic energy distribution diagram; extracting the energy concentration degree, peak value offset and bandwidth expansion coefficient in a characteristic frequency band, inputting a pre-trained multilayer perception classifier, and outputting a fault type. Through high-precision time-frequency focusing and multi-dimensional feature fusion, the application significantly improves fault recognition accuracy and robustness, and can realize online diagnosis of various typical faults only by using current signals.

The invention provides an axial motor magnetic flux density total distortion rate evaluation method, which comprises the following steps: identifying each harmonic amplitude attenuation caused by air gap radial spacing fluctuation from optimized sampling data, and determining a distortion energy concentration frequency point corresponding to each harmonic amplitude attenuation; extracting an abnormal frequency component from the actually existing harmonic amplitude according to a distortion energy concentration frequency point, identifying a corresponding relation between the abnormal frequency component and a fundamental frequency rising amplitude when the number of pole pairs is increased, and determining a preliminary evaluation value of a total distortion rate; the harmonic components exceeding the normal amplitude boundary and the manufacturing source attributes of the harmonic components are evaluated, the proportion of abnormal harmonic energy caused by winding asymmetry and air gap non-uniformity is separated from the harmonic components, and the distribution condition of distortion energy in each frequency band is evaluated and classified and identified; and according to a source classification identification result of the distortion energy, carrying out preliminary correction on the preliminary evaluation value of the total distortion rate, and determining an evaluation index of the axial motor magnetic flux density total distortion rate.

The invention discloses a differential mode filter with voltage and current harmonic suppression and a parameter determination method, and relates to the technical field of motor driving, the differential mode filter mainly comprises an impedance bridge, an isolation transformer and an LCL filter circuit which are connected between an inverter and a motor and are in cascade connection in sequence, comprising three single-phase bridge units which are connected in parallel, each single-phase bridge unit is composed of two LC bridge arms which are connected in parallel, inductors and capacitors in the two LC bridge arms are of an anti-parallel symmetrical structure, and the capacitors in the LC bridge arms are connected with a first damping resistor which is used for inhibiting harmonic amplification in series; the isolation transformer is used for realizing electrical isolation between the impedance bridge and a post-stage circuit; and the LCL filter circuit is used for eliminating current harmonics which are more than frequency multiplication of the switching frequency. According to the invention, a deep notch effect can be generated on switching frequency sub-harmonics, voltage and current harmonics of a frequency point are suppressed, harmonic energy is reduced from the source, and the size of the filter is reduced at the same time.