177 results about "Harmonic analysis" patented technology

The invention relates to the technical field of pipe network data processing, in particular to an automatic monitoring data processing method for pipe network pressure. The method comprises the following steps: acquiring pipe network structure data; constructing a pipeline topology network based on the pipe network structure data to generate the pipeline topology network; screening main pipelines and branch pipes of the pipeline topology network to obtain pipe network circulation data; carrying out pipe wall microwave resonator deployment on the main pipeline and the branch pipelines based on the pipe network circulation data, and capturing pipeline circumferential deformation harmonic waves in real time through the deployed microwave resonators; longitudinal wave propagation time delay of pipe network circulation data is analyzed, and a pipe body structure dynamic resonance atlas is constructed in combination with pipeline circumferential deformation harmonic waves; and carrying out pipe network internal pressure and pipe wall equivalent stress calculation on the pipeline topology network through a pipe body structure dynamic resonance map. By combining pipeline topology analysis, microwave resonator monitoring, dynamic resonance spectrum and bidirectional fluid-solid coupling analysis, the accuracy of pipe network pressure monitoring and identification is improved.

The invention belongs to the technical field of power monitoring, and discloses a detection method for monitoring the state of a primary and secondary fusion circuit breaker, which comprises the following steps: acquiring state data of the circuit breaker, including electromagnetic waveform data, harmonic response characteristics and temperature distribution gradient; obtaining circuit breaker electric field distribution fingerprints through nonlinear segmented harmonic analysis, constructing a multi-dimensional permeation characteristic matrix, and establishing a micro-scale electrothermal coupling map; performing impedance distortion analysis to obtain a nonlinear region situation table, performing multi-frequency response analysis to obtain a harmonic penetration curve, and constructing a high-frequency harmonic penetration path spectrum; a micro-region diagnosis algorithm is established, nonlinear impedance calibration is carried out, and a multi-level protection instruction sequence is generated; adjusting the operation state of the circuit breaker to obtain a circuit breaker medium steady-state index, and performing risk analysis to obtain a harmonic penetration early warning report; according to the invention, accurate identification and early warning of the abnormal-state area in the circuit breaker are realized, and the safe and stable operation capability of the primary and secondary fusion circuit breaker is improved.

The invention provides an operation optimization method and system based on electric power data conjoint analysis, and the method comprises the steps: obtaining synchronous sampling data and power grid topological parameters of a wide-area electric power system; performing equipment state evaluation, broadband resonance traceability and harmonic responsibility quantification on the synchronous sampling data and the power grid topological parameters by using a conjoint analysis engine, and generating a power grid control strategy; and carrying out operation optimization on the power equipment in the wide-area power system based on the power grid control strategy. According to the method, conjoint analysis is carried out on equipment state evaluation, broadband resonance traceability and harmonic responsibility quantification of the wide-area power system, traditional static spectrum analysis is upgraded to dynamic behavior perception, the power grid analysis depth and accuracy can be improved, the high-frequency harmonic analysis requirement can be met through broadband resonance traceability, and the method is suitable for large-scale popularization and application. Intelligent analysis can be realized for different application scenes, the waveform analysis capability and the frequency response range are improved, and the analysis effect is improved.

The invention discloses a tidal reach water level and flow relation analysis method based on tidal level harmonic analysis. The method comprises the steps of collecting actually measured water level data, basin river topography and digital elevation data of a tidal reach hydrologic station; characteristic parameters and water surface elevation change characteristics of all partial tides of the tide level of the tidal river reach are obtained on the basis of tide level harmonic analysis, and then independent tide flow and river runoff flow are obtained; establishing a tidal reach one-dimensional hydrodynamic model, and analyzing a flow change process and a water level flow change relation under different water level change scenes; and analyzing the contribution degree of the tidal flow and the river runoff to the actual flow and the change process by utilizing a multivariate regression analysis and drift diameter analysis method to obtain the change characteristics of the water level and flow relationship of the tidal reach. The method has the advantages that the water level and flow relation of the tidal reach can be rapidly analyzed, complex estuary hydrodynamic process simulation is not needed, and the method is also applicable when actually measured flow data is lacked.

The invention discloses a drilling construction intelligent decision support and risk early warning method, device and equipment, and the method comprises the steps: collecting drilling sound wave response data, carrying out harmonic analysis to recognize a reservoir resonance node, and constructing a reservoir energy conduction network; a fluctuation propagation path is tracked based on an energy conduction network, and a construction risk area is identified through stress wave spectrum features; porosity and permeability data are extracted for phase difference analysis, a seepage-construction mismatch factor is generated, and a construction optimization window is actively generated; constructing a geological potential energy gradient field to determine an overflow influence range, and performing tensor coupling on multi-dimensional risk factors to generate a three-dimensional construction decision matrix; an optimal construction scheme is generated through energy minimization and risk-efficiency dynamic balance processing; construction parameter response changes are monitored in real time, abnormal parameter combination symptoms are recognized, a grading risk early warning instruction is generated, and intelligent decision support and risk early warning of drilling construction are achieved.

The invention discloses a multi-factor coupling dynamic error compensation method, system and device and a storage medium, and the method comprises the steps: obtaining an original signal sequence, and carrying out the time-frequency analysis of the original signal sequence, and obtaining a time-frequency matrix; performing feature extraction on the time-frequency matrix to obtain feature information; according to the feature information, calculating a Lagrange interpolation reference node of a corresponding time point, and carrying out signal reconstruction to obtain a synchronous sampling sequence; performing harmonic analysis on the synchronous sampling sequence to obtain harmonic parameters; the dynamic compensation amount is calculated in combination with the characteristic information and the harmonic parameters, the electric energy metering value is corrected, and the real-time performance and accuracy of electric energy measurement are effectively improved.

The invention relates to the technical field of mechanical vibration and fluid excitation coupling effect analysis, in particular to a runner crown modification pressure pulsation amplitude measurement method, which comprises the following steps of: extracting pressure gradient distribution and cavitation phase change characteristic parameters of a runner surface through fluid dynamics simulation; targeted arrangement of a high-frequency pressure sensor array in a vortex core area, a boundary layer separation critical position and a modification structure mutation area is guided, and the signal acquisition precision is improved by adopting an annular encryption and axial equal-interval arrangement strategy. And establishing a dynamic error feedback mechanism of actual measurement and simulation. And verifying an abnormal frequency band proportion through frequency domain kurtosis and analyzing envelope spectrum harmonic waves, and screening a modification parameter combination with the pressure pulsation amplitude decreasing to reach the standard and stable frequency band distribution. According to the method, the problem of measurement errors caused by multi-source high-frequency noise and effective signal frequency domain aliasing is solved, a high-precision quantification basis is provided for runner modification optimization, and the method is suitable for the field of mechanical system dynamic characteristic testing.

The invention relates to the technical field of elevator operation and maintenance, and discloses a multi-source data fusion method and system for elevator fault localization, and the method comprises the steps: carrying out the noise filtering and data alignment of multi-source monitoring data of an elevator during operation, and obtaining a monitoring data set; performing time-frequency analysis on acceleration sensor data in the monitoring data set to obtain vibration mode characteristics; performing harmonic analysis on the motor current data to obtain current distortion characteristics; performing space-time correlation on the vibration mode characteristics, the current distortion characteristics and the safety loop state in the monitoring data set to obtain a comprehensive fault characteristic vector; according to the comprehensive fault feature vector, specific components and types when the elevator breaks down are determined, so that fault positioning information is obtained; the fault positioning information is transmitted to an elevator monitoring terminal, and the elevator is maintained according to the fault positioning information; according to the invention, the fault positioning efficiency can be improved.

The invention discloses an intelligent power grid equipment fault monitoring system and method based on the Internet of Things, and relates to the technical field of the Internet of Things. Discrete Fourier transform and a Fisher information processing method are adopted to fuse multi-source data, meteorological interference is corrected, and accurate collection of electrical quantity and quantification of environmental influence are achieved; and setting a fault monitoring sliding window and a harmonic analysis time interval, and obtaining harmonic data of different time scales. Extracting harmonic features through slope calculation, and identifying voltage abnormal features; historical data is processed according to a time sequence prediction algorithm to construct a prediction set, voltage abnormity is judged based on a historical data threshold value, intelligent early warning of the voltage state is achieved, the abnormity capturing precision is improved, and when the system detects the voltage abnormity, information of strain section equipment sending out a fault early warning signal is obtained and transmitted to an OTA upgrading terminal. And enabling the OTA upgrading terminal to carry out state identification and data interaction on the upgrading process of the intelligent power grid equipment based on the equipment information.

The invention relates to the technical field of optical current transformer detection, and provides an optical current transformer real-time calibration and health diagnosis method and system, and the method comprises the steps: carrying out the harmonic analysis of an initial digital signal sequence obtained through the conversion of a continuous modulation optical signal of a target optical current transformer, and obtaining harmonic component data; physical state evaluation is carried out according to the higher harmonic component data and preset health state baseline data to generate a physical state evaluation result, nonlinear disturbance compensation is carried out according to an error control signal generated based on the higher harmonic component data, and after a linear working point is reached, nonlinear disturbance compensation is carried out; and calculating an electrical measurement value according to the output target fundamental component data, and performing comprehensive analysis according to the physical state evaluation result and the electrical measurement value to generate a diagnosis report. According to the invention, through a measurement calibration and state diagnosis mechanism based on harmonic analysis, while the electrical performance measurement precision is effectively improved, reliable quantitative diagnosis and accurate traceability of different physical faults in the equipment are realized.

The invention discloses a tidal harmonic analysis method and device based on a tidal time-varying mode, and high-precision processing of tidal data and dynamic updating of harmonic constants are realized by constructing a complete technical route including gross error detection, default filling, time-varying analysis and sequential adjustment. According to the method, firstly, actually measured water level observation data are collected, a water level residual error sequence after long-term trend and periodic components are removed is extracted based on seasonal trend decomposition, statistical analysis is conducted on the residual error sequence through a gross error detection method based on standard deviation and quartile distance, and abnormal data are accurately recognized and removed. And carrying out smooth recovery on default data by adopting an interpolation filling algorithm based on cubic Hermite and fast Fourier transform, and constructing continuous and complete water level time sequence data. According to the method, the data quality is effectively improved, the change rule of tide parameters can be reflected more truly, and the precision of tide correction operation in ocean sounding is remarkably improved.

The invention discloses a current-driven dielectric loss and electric energy quality joint detection system, which relates to the technical field of electric power systems and comprises a voltage and current acquisition module, a harmonic analysis module, a voltage and current detection module, a voltage and current detection module, a voltage and current detection module, a voltage and current detection module and a voltage and current detection module, and the voltage and current detection module is used for real-time acquisition of voltage and current signals from a to-be-detected circuit and extraction of time domain and frequency domain characteristics. The harmonic analysis module is used for carrying out harmonic analysis on a nonlinear load based on extracted voltage and current signal characteristics and identifying various harmonic components, the electric energy quality evaluation module is used for constructing an electric energy quality evaluation model according to a harmonic analysis result and quantifying an energy efficiency index of the nonlinear load, and the report generation module is used for generating a report. The analysis module outputs a final analysis report according to the power quality evaluation result; according to the current-driven dielectric loss and electric energy quality joint detection system, full-process automation from data acquisition to harmonic analysis, problem evaluation to optimization suggestion generation can be realized, and the precision, efficiency and stability of monitoring and optimization of an electric power system are improved.

The invention discloses a power supply system and method for substation equipment, and relates to the technical field of substation power supply, and the system comprises a data collection module which is used for synchronously collecting three-phase voltage and current signals of a substation load; the harmonic characteristic analysis module is used for carrying out harmonic analysis on the collected signals and calculating the amplitude and phase dispersion of each harmonic; the dynamic weight calculation module is used for calculating a dynamic harmonic weight factor according to the harmonic analysis result; the equivalent reactive power decision module is used for calculating equivalent reactive power and generating an optimal capacitor switching instruction in combination with harmonic weight and temperature compensation; the temperature compensation module is used for monitoring the temperature of the capacitor in real time and calibrating the actual capacity of the capacitor; and the flexible switching execution module is used for triggering a thyristor near the voltage zero crossing point. By constructing the harmonic phase dispersion analysis mechanism and the harmonic weight factor dynamic correction model, the transient characteristic and steady-state distortion difference of the load harmonic can be analyzed more accurately.

The invention belongs to the technical field of grid-connected inverter harmonic analysis, and particularly discloses a grid-connected inverter harmonic closed-loop transmission analysis method and system considering broadband coupling. The method comprises the following steps: respectively establishing a harmonic component transfer function of each module; based on the harmonic component transfer function of the sampling module, calculating to obtain harmonic active power and harmonic reactive power input to the power outer loop control module; based on a harmonic component transfer function of the power outer loop control module, calculating to obtain a harmonic current component in a reference current signal output by a power outer loop; based on a harmonic component transfer function of a current inner loop control module, obtaining a three-phase modulation voltage harmonic component and an inverter port voltage harmonic component through coordinate inverse transformation; on the basis of the inverter port voltage harmonic component, a main circuit harmonic transfer equation is combined, and a grid-connected point harmonic current component is obtained through calculation; the method overcomes the defects that a traditional analysis method cannot consider the control of a whole loop by a closed loop, and the broadband coupling is insufficiently considered.

The invention discloses a sensorless galloping starting control method for a CAES high-voltage frequency converter. The sensorless galloping starting control method comprises the steps of collecting output voltage and stator current data of the frequency converter; harmonic analysis is carried out on the normalized data, and a position estimation dead zone is identified through sensitivity evaluation; designing a quadrature phase modulation sequence for the dead zone; applying a modulation sequence to generate a harmonic interference mode; calculating harmonic response differential fingerprints, and extracting enhanced position features; meanwhile, torque fluctuation in the modulation process is predicted and compensated, and the system stability is guaranteed; and realizing stable galloping starting based on the accurate position. The position estimation dead zone problem is solved through the phase interference principle, the position precision is improved to + / -3.5 degrees, and the starting reliability is remarkably improved.

The invention relates to a distortion degree measuring system and method based on correlation operation, and the system comprises a signal source which is a to-be-measured signal source for outputting a mixed waveform comprising a fundamental wave and each harmonic component; the fundamental wave extraction module is used for separating and extracting a fundamental wave component of which the waveform is a single-frequency square wave from the signal to be detected; the phase-locked loop frequency multiplication module is used for receiving the fundamental component and locking and extracting a sine wave signal containing the fundamental component and a harmonic component through a phase-locked loop containing a programmable frequency divider; the correlator module is composed of a multiplier circuit and a low-pass filtering and amplifying circuit, receives a to-be-measured signal serving as an input signal and a sine wave signal serving as a reference signal, and outputs a direct-current component; and the single chip microcomputer is configured with the programmable frequency divider, samples the direct current component output by the correlator module, calculates the relative amplitude and the total harmonic distortion degree of the fundamental wave component and the harmonic component, and outputs the total harmonic distortion degree. The beneficial effects are that the measurement system and the signal processing method are suitable for signal harmonic analysis under a complex harmonic environment and a low signal-to-noise ratio condition, a high-performance processor and a computing power requirement are not needed, and the system takes an analog circuit as a main body and has the advantages of high measurement speed, high accuracy, low system cost and the like.

The invention relates to the technical field of power supply and generation of micro-grids, and provides a power supply and generation regulation and control method based on an optical storage and utilization integrated new energy micro-grid, which comprises the following steps of: acquiring initial real-time operation data of the new energy micro-grid, preprocessing the initial real-time operation data to obtain real-time operation data, and storing the real-time operation data in a database; based on the photovoltaic power generation prediction model, the real-time photovoltaic power generation data and the real-time meteorological data, predicting the photovoltaic power generation capacity change trend of the new energy microgrid, and based on the load demand prediction model and the real-time load data, predicting the load demand change trend of the new energy microgrid. Performing harmonic analysis on the new energy microgrid based on the voltage and current waveform data to obtain a total harmonic distortion rate; generating a multi-target scheduling scheme based on a multi-target optimization algorithm, the real-time operation data and the prediction data; and performing priority management on the system load of the new energy micro-grid based on the multi-target scheduling scheme, and regulating and controlling the power supply and generation strategy of the new energy micro-grid. According to the invention, comprehensive optimization regulation and control of photovoltaic power generation, energy storage, load requirements and harmonic distortion of the new energy micro-grid are realized, and integration of light, storage and utilization of the new energy micro-grid is realized.

The invention provides a tide level prediction method and device and a server, and relates to the technical field of tide prediction, the method is applied to a tide level prediction model, the tide level prediction model comprises a harmonic analysis model, and the method comprises the following steps: carrying out harmonic analysis processing on original tide level data through the harmonic analysis model, determining an astronomical tide predicted value and non-astronomical tide data of the tide; performing decomposition and noise reduction processing on the non-astronomical tide data, determining various modal components of the non-astronomical tide, and determining a non-astronomical tide predicted value based on the gating cycle model and the modal components; and superposing the non-astronomical tide predicted value and the astronomical tide predicted value to determine a target tide level predicted value. The precision of tide level prediction can be remarkably improved.

The invention relates to the technical field of motor diagnosis, and discloses a motor eccentricity fault diagnosis method and system based on current harmonic analysis, and the method comprises the steps: carrying out the power frequency component extraction of a three-phase stator current signal, obtaining a residual current signal, carrying out the complex analysis envelope transformation of the residual current signal, and obtaining an envelope analysis signal; performing synchronous interpolation resampling on the envelope analysis signal to obtain a complex envelope signal; performing frequency spectrum estimation on the complex envelope signal to obtain a discrete frequency spectrum of a module value sequence; performing equalization processing on the order spectral line amplitude in the discrete spectrum to obtain a whitened spectrum, and performing inverse transformation on the whitened spectrum to reconstruct an angular domain amplitude signal of the target motor; performing cyclostationary analysis on the angular domain amplitude signal to obtain a third-order cyclic cumulant of the angular domain amplitude signal at a specific cyclic frequency; according to the third-order cycle cumulant, the type and severity level of the eccentric fault are judged; the accuracy of motor eccentricity fault diagnosis can be improved.

The invention discloses a rotor turn-to-turn short circuit diagnosis method based on an exciting current-shaft voltage harmonic nonlinear correlation coefficient. The method comprises the following steps: synchronously collecting parameters, and preprocessing the collected parameters through wavelet threshold denoising and temperature normalization; extracting harmonic analysis according to the shaft voltage harmonic characteristics; identifying magnetic saturation, temperature and load nonlinear factors and calculating corresponding coefficients; performing dynamic correction on the Pearson's correlation coefficient through the nonlinear correction coefficient, and combining with fuzzy logic weighting to obtain fuzzy logic weighting; defining a working condition feature vector, and constructing a working condition adaptive dynamic model comprising a linear regression basic model and an LSTM neural network; and calculating a dynamic threshold value based on the basic threshold value and the nonlinear factor, and judging the turn-to-turn short circuit trend of the rotor according to the comparison of the correlation coefficient and the dynamic threshold value and a prediction result. According to the invention, through combination of the nonlinear correction correlation coefficient and the LSTM neural network, dynamic compensation of nonlinear factors is realized, and the accuracy and reliability of rotor turn-to-turn short circuit fault diagnosis are improved.

The invention provides a data processing method and device for an intelligent acquisition terminal, and the method comprises the steps: determining whether a current signal is in a smooth or linear change stage or a rapid change stage according to the ratio of the first-order difference to the absolute value of a preset signal change rate threshold value; according to the method, a sampling interval is dynamically adjusted according to a change condition of a signal, so that the collected data can reflect a waveform change condition of the signal, then key feature point data collected within a preset sampling duration is determined, and a data packet of a key moment where a key feature point is located is constructed; the key feature point data can reflect the amplitude and the key time domain of the signal waveform, and the characteristics of the signal waveform can be restored through the amplitude and the key time domain, so that the relatively accurate signal waveform is obtained, the distortion condition during subsequent harmonic analysis is reduced, and the accuracy of power grid state judgment is improved.

The invention discloses an asynchronous motor control method based on scraper load prediction, and the method comprises the steps: detecting the characteristics of a multi-source load based on a vibration sensor, current harmonic analysis and mechanical transmission parameters, predicting the probability distribution and confidence interval of a load torque outputted by a network through combining with an LSTM time sequence, and providing a prospective input for a decision. And based on a prediction result, multi-motor energy distribution is realized by utilizing a dynamic weighting function and Nash game optimization, time-varying parameter deviations of rotor resistance and mutual inductance are respectively compensated based on a BP neural network and extended Kalman filtering, and meanwhile, instantaneous overload protection is realized by adopting a two-stage load reduction strategy driven by reinforcement learning. According to the invention, a DTC-SVM algorithm is integrated, and a control instruction is accurately executed based on predicted torque compensation, variable switching frequency adjustment and dual-target optimization in combination with a real-time error detection and hardware protection module. According to the scheme, the dynamic response speed, the energy efficiency and the operation reliability of the asynchronous motor under the periodic impact load are remarkably improved.

The invention discloses an ocean inner tidal current velocity prediction method, system and device and a medium. The method comprises the following steps: acquiring historical inner tidal current velocity data of a target sea area; and inputting the historical internal tidal current velocity data into a preset internal tidal current velocity prediction model to obtain an internal tidal current velocity prediction result of the target sea area output by the internal tidal current velocity prediction model, so that the problem of large prediction error caused by the fact that a traditional internal tidal current prediction method based on harmonic analysis cannot predict an incoherent internal tidal current part can be solved. And meanwhile, an internal tide flow velocity prediction model can be trained by using relatively few training resources, so that a full-depth high-precision internal tide prediction result of different sea area conditions can be obtained through prediction.

The invention discloses a broadband harmonic voltage measuring system and method based on an improved CVT, and the system comprises a first current sensor which is used for measuring the first current of a high-voltage capacitor of the CVT; the broadband harmonic wave acquisition device is used for sampling the first current to obtain first current sampling data; and the broadband harmonic analysis device is used for determining an amplitude frequency spectrum of the first current based on the first current sampling data and determining each frequency component of the system voltage based on the amplitude frequency spectrum of the first current. On the basis of a large number of CVTs used in a power system, the broadband harmonic voltage measurement function within the range of hundreds of kHz is achieved by improving the CVT, the original power frequency measurement function of the CVT is not changed, the operation reliability of the CVT is not reduced, and effective broadband, high-precision and low-cost harmonic voltage measurement can be achieved.

The invention relates to a power distribution network harmonic analysis method and system, and the method comprises the steps: constructing a digital twinborn model of a power distribution network region, and selecting transformers in the region as analysis objects one by one; for each analysis object, various working conditions are simulated by changing the transformation ratio of the analysis object in a digital twin model, and voltage and current waveforms are collected and subjected to Fourier decomposition to obtain harmonic phasors; thirdly, performing phase reduction on the phasor data, separating a real part from an imaginary part to construct a matrix, and solving a harmonic coefficient matrix by using a least square method to realize error minimization; separating linear and nonlinear parts of the harmonic current, and calculating a harmonic emission capability parameter and a harmonic current risk parameter for quantitative evaluation; according to the method, all transformers are traversed and analyzed, and systematic harmonic evaluation of the whole power distribution network area is finally realized.

To provide a flicker value calculation and power supply harmonic analysis device capable of estimating flicker values and power supply harmonic analysis results compliant with required standards while being connected to a commercial power supply.SOLUTION: A processor is configured to store a measured voltage and measured waveform thereof in a memory, extract voltage and current waveforms within a predetermined time range from the measured voltage and measured waveform thereof stored in the memory, perform a standard-compliant power supply harmonic calculation current conversion for converting the extracted voltage and current waveforms into voltage and current waveforms when connected to a power supply compliant with predetermined standards, analyze the power supply harmonic current from the converted current waveform, perform a standard-compliant flicker value calculation voltage conversion for converting the extracted voltage and current waveforms into voltage and current waveforms when connected to a power supply compliant with predetermined standards and a reference impedance network, calculate a flicker value from the converted voltage waveform, and output results of the power supply harmonic analysis and the calculated flicker value to an output interface.SELECTED DRAWING: Figure 1

The present invention discloses a method for identifying and suppressing coupled space-time harmonics of torque pulsation and vibration noise, relating to the field of air gap magnetic field harmonic analysis and optimization of permanent magnet motors. The method comprises: using a precise finite element model with a uniformly distributed air gap grid to obtain the two-dimensional space-time electromagnetic force and magnetic flux waveforms in the air gap; obtaining and identifying the physical characteristics of the space-time harmonics of the electromagnetic force and magnetic flux density in the air gap; determining the most critical space-time harmonics of the electromagnetic force; treating the space-time harmonics as vectors rotating with time and space, and identifying the coupled space-time harmonics based on the space-time invariance of the graph composed of vectors of the same order; suppressing the key coupled space-time harmonics without destroying the periodicity of the magnetic field; and verifying the torque pulsation and vibration noise of the optimized model through a multi-field coupling method. The present invention proposes for the first time a method for identifying the coupled space-time harmonics of torque pulsation and vibration noise in permanent magnet motors. By suppressing the key coupled space-time harmonics, the torque pulsation and vibration noise of permanent magnet motors can be simultaneously reduced.

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 present application relates to a kind of Fourier transform-based ATSE power harmonic analysis method, comprising the following steps: collecting each AD data, each AD value is processed by central axis zeroing;After each AD value processed by central axis zeroing, Fourier transform calculation is carried out, and the harmonic content of each waveform is obtained;According to each harmonic content, total harmonic content is obtained;According to total wave effective value and total harmonic content, further obtain fundamental effective value;Through the fundamental effective value and each harmonic content, control logic analysis power state is assisted.The present application is based on Fourier transform harmonic analysis method, helps automatic transfer switch to analyze the harmonic content of current power, so that controller more comprehensive analysis power state, more suitable switching mode is selected according to load condition, further improve the safety and reliability of dual power automatic transfer switch, maintain the normal operation of entire power system, protect electrical equipment and reduce power loss.