127 results about "Harmonic amplitude" patented technology

The invention relates to the technical field of power supply detection, and discloses a fire-fighting equipment power supply detection method and system.The detection method comprises the following steps that voltage fluctuation, current phase and ripple coefficients are collected through a multi-channel sensor group, a feature sequence is generated through sliding window noise reduction, the Euclidean distance is calculated through Z-score standardization, and a calibration instruction is generated when a threshold value is exceeded; kalman filtering adjusts frequency output detection parameters, fast Fourier transform is executed to extract harmonic amplitude to generate a suppression vector, and a least square reconstruction model outputs a state identifier; according to the method, voltage, current and ripples are collected through multiple channels, anti-interference performance and data integrity are enhanced through sliding window noise reduction, a threshold value is adjusted through Z-score and Euclidean distance self-matching, sampling frequency and detection parameters are optimized through Kalman filtering, harmonic characteristics are extracted through FFT, and the state is evaluated through a least square reconstruction model. And a multi-dimensional classification system is constructed by fusing the distortion rate and the phase deviation, so that the detection precision, the sensitivity and the response real-time performance are improved.

The invention provides a non-intrusive diagnosis method for typical rotor faults of a synchronous phase modifier, and the method comprises the steps: carrying out finite element modeling and fault working condition setting, carrying out simulation to obtain magnetic field distribution data under each working condition, carrying out the extraction and feature analysis of stray magnetic field signals, extracting time domain and frequency domain signals of a stray magnetic field under healthy and various fault working conditions, and carrying out the diagnosis of the typical rotor faults of the synchronous phase modifier. Fundamental wave, odd-even harmonic components and signal change trends are compared and analyzed, stray magnetic field characteristics corresponding to faults are extracted and recognized, diagnosis criterion establishment and fault recognition are carried out, diagnosis criteria and threshold values of rotor turn-to-turn short circuit, dynamic eccentricity and shaft-diameter composite eccentricity faults are established according to the stray magnetic field characteristics, and the fault diagnosis accuracy is improved. And when the specific harmonic amplitude or change characteristic of the stray magnetic field signal exceeds the criterion threshold, determining the rotor fault of the corresponding type and degree. Equipment dismounting or structure reconstruction is not needed, the detection system is simple in structure, internal fault characteristics of the phase modifier can be reflected in real time, and high sensitivity and practicability are achieved.

The invention discloses an LSTM (Long Short Term Memory)-based harmonic frequency coupling model optimization method for a network construction type converter, which considers the influence of a dead zone and establishes a converter model controlled by a virtual synchronous generator based on a harmonic state space method. In the power electronic modeling process, due to approximate simplification, switch neglecting and other nonlinear relations, the model is not accurate enough, meanwhile, in the harmonic state space model modeling process, system state variable parameters need to be considered, and the precision of the model affects harmonic transmission characteristics and coupling analysis, so that the modeling efficiency is greatly improved. Errors caused by power electronic modeling are reduced through an LSTM neural network algorithm, the harmonic amplitude estimation difference is reduced, state variable parameter values in a system model are accurately estimated, the model precision is further improved, and then the harmonic coupling condition under the dead zone influence is effectively and accurately analyzed.

The invention relates to the technical field of power distribution network fault detection, and discloses a power distribution network high-resistance grounding fault intelligent detection method, system and device and a medium, and the method comprises the steps: collecting a power distribution network line transient signal which comprises a transient zero-sequence voltage signal and a transient zero-sequence current signal; preprocessing the transient signal and extracting a multi-dimensional feature set for representing high-resistance grounding fault characteristics, wherein the multi-dimensional feature set comprises a transient energy feature, a wavelet entropy feature and a harmonic component feature; and inputting the extracted multi-dimensional feature set into a pre-trained machine learning model, and simultaneously outputting a judgment result of the high-resistance grounding fault and an estimated value of the grounding resistance through the machine learning model. According to the method, the transient energy, the multi-scale wavelet entropy, the odd harmonic amplitude and the phase, which are derived from different analysis domains and have complementary physical meanings, are deeply fused, so that the problem that a single feature is weak in characterization capability and easy to fail under the conditions of high noise and high resistance is effectively solved.

The application discloses a kind of water electrolysis hydrogen production rectifier transformer harmonic active inhibition optimization method, comprising the following steps: constructing rectifier circuit, rectifier circuit includes switch tube, the voltage vector and zero vector of switch tube output are combined, and combined output voltage vector is obtained;The harmonic amplitude is obtained by processing combined output voltage vector, Levy tangent flight strategy and confidence domain variation strategy are introduced in black-winged kite optimization algorithm to construct improved dynamic search algorithm, the total harmonic distortion is obtained by iterative calculation of harmonic amplitude by improved dynamic search algorithm, i.e. optimal switch tube combination, the switch tube of rectifier circuit is adjusted by optimal switch tube combination, and the total harmonic distortion of rectifier circuit is reduced.The optimal switch tube combination of rectifier circuit is iteratively calculated by improved dynamic search algorithm in the application, effectively reduces resource consumption, and processing speed is accelerated, and the efficiency and accuracy of electrolytic water hydrogen production rectifier are improved.

The invention relates to the field of permanent magnet synchronous motor control, in particular to an RANF adaptive harmonic suppression method based on dustpan line optimization, which comprises the following steps: S1, establishing a d-q axis control model for a permanent magnet synchronous motor, listing voltage, current and electromagnetic torque equations, giving a harmonic current equation, and adopting an ANF adaptive notch extraction algorithm to obtain a harmonic current control model for the permanent magnet synchronous motor; obtaining estimated values of specific-order harmonic amplitude and phase, and generating harmonic compensation quantity from the estimated values by adopting a PI regulator so as to realize a steady-state indifference-free harmonic suppression effect; and S2, in order to solve the problem that the ANF adaptive harmonic suppression algorithm is difficult to follow the d-q axis current rapidly changing along with the direct current amount, an RANF adaptive harmonic suppression algorithm adopting an R regulator is proposed, the ANF following performance is greatly accelerated, and the practicability of the ANF is improved. When the motor load or the rotating speed changes, quick response can be achieved, system instability is avoided, the dynamic stability of the system is remarkably improved, and the application scene of ANF adaptive harmonic suppression in the permanent magnet synchronous motor is widened.

The invention discloses a modularized multi-level converter fault positioning method based on TimesNet and a harmonic theory. The method comprises the following steps: carrying out bridge arm voltage sampling on a modularized multi-level converter to obtain a bridge arm voltage signal; carrying out harmonic parameter estimation on the bridge arm voltage signal based on a pre-trained Times Net network to obtain a harmonic amplitude, a harmonic phase and a background noise level; carrying out self-adaptive correction on a preset basic amplitude threshold according to the background noise level to obtain a dynamic amplitude threshold; and when the harmonic amplitude is greater than the dynamic amplitude threshold, determining that the modular multilevel converter has a fault, and positioning the fault sub-module according to the harmonic phase. The method improves the fault positioning accuracy and reliability of the modular multilevel converter, and can be applied to the technical field of DC power transmission and transformation.

The invention discloses a virtual simulation analysis method and system for global perception of a low-voltage power distribution network, and relates to the technical field of power grid simulation, and the method comprises the steps: constructing a dynamically updated adjacency matrix through linear weighted fusion and an exponential decay function, and representing the correlation strength between nodes; screening a high-correlation path as an initial fault diffusion path according to the dynamic adjacency matrix, verifying logic rationality of a phase abrupt change time sequence and circuit breaker action time in combination with recording data, reserving an effective propagation channel after a time sequence conflict path is eliminated, and calculating a theoretical harmonic amplitude by distributing a harmonic transfer coefficient, so as to realize fault diagnosis. And comparing with actual data layer by layer to generate an error vector, iteratively correcting time-frequency domain weight parameters until errors converge, positioning a fault source and generating a simulation report containing a path matching degree. According to the invention, high-precision positioning of the fault source of the low-voltage power distribution network and dynamic simulation matching of the propagation path are realized, and the accuracy of fault diagnosis and the reliability of power grid state analysis are effectively improved.

The invention discloses a metering equipment remote calibration method and device, a medium and equipment. The method comprises the following steps: calculating a loss index according to current characteristics of an extracted current signal in a monitoring period, and determining a phase offset of each harmonic based on the loss index; constructing an environment gain coefficient according to the environment temperature and the environment humidity in the environment management period; constructing a current correction coefficient according to the fundamental wave amplitude of the current signal in the monitoring period and the environment gain coefficient; and correcting each harmonic amplitude in the next monitoring period according to the current correction coefficient, and correcting each harmonic phase in the next monitoring period according to the phase offset of each harmonic to obtain a calibration current in the next monitoring period.

The invention belongs to the technical field of ultrasonic imaging, and particularly relates to an ultrasonic nonlinear parameter imaging method and system, a medium and a program product. The method comprises the following steps: calculating a fundamental signal and a harmonic signal based on an ultrasonic echo RF signal; extracting the amplitude of the fundamental wave signal and the amplitude of the harmonic wave signal, and calculating to obtain a fundamental wave amplitude ratio and a harmonic wave amplitude ratio; calculating an initial value of a nonlinear coefficient according to a ratio of the fundamental wave amplitude ratio to the harmonic wave amplitude ratio, and estimating a value range of the nonlinear coefficient by using a Newton iteration method; and generating an ultrasonic image based on the value range of the nonlinear coefficient. In the ultrasonic non-linear parameter imaging process, a method for solving a non-linear coefficient by adopting a Newton iteration method is further disclosed, so that the dynamic range of the estimated non-linear coefficient value is expanded, the distinguishing between normal tissues and focus tissues in an obtained ultrasonic image is more obvious, and the sensitivity is higher.

The application relates to a semiconductor package failure detection method based on high harmonic amplitude-phase demodulation, and relates to the technical field of semiconductor package detection. The application is used to solve the problems existing in the prior art semiconductor package defect detection method. The application applies a current excitation to a measured semiconductor package to make the semiconductor package generate heat, and collects a thermal image sequence of the semiconductor package; a same-frequency quadrature reference signal of each harmonic of the thermal image sequence is synthesized according to the current excitation; a demodulation phase is extracted by using the same-frequency quadrature reference signal; a dominant path is extracted according to a fourth-order demodulation phase; the dominant path is verified according to a fifth-order and sixth-order demodulation phase; if the dominant path is verified to be correct, it is determined that the measured semiconductor package has a failure state corresponding to the dominant path; otherwise, the thermal image sequence of the measured semiconductor package is collected again for detection. The application is suitable for the fields of semiconductor package manufacturing and testing, quality and reliability control, failure analysis and the like.

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 harmonic analysis method based on double buffer window function optimization, and relates to the technical field of harmonic analysis and signal processing of a power system, and the method comprises the steps of hardware initialization, double buffer initialization, FFT module parameter configuration, data acquisition, buffer switching, data extraction and windowing and FFT processing. Parallel data acquisition and processing are realized through a double-buffer ping-pong mechanism, spectrum leakage is suppressed by applying a Hanning window function, and FFT calculation is performed after signal amplitude is recovered through a compensation factor; according to the method, the data acquisition continuity and real-time performance are improved, the harmonic amplitude error is controlled within + / -0.5%, the hardware resource utilization rate is optimized, and the method is suitable for power grid electric energy quality monitoring.

The invention relates to the technical field of oil-gas exploration data processing, and discloses a data weak information processing method, system and device and a medium. The method comprises the following steps: optimizing time domain signal data of all frequencies in a target layer, and calculating full-band amplitude corresponding to each excitation frequency according to each optimized time domain signal data; judging whether each excitation frequency is greater than a preset frequency; if the excitation frequency is greater than the preset frequency, extracting a plurality of low-order harmonic amplitudes of the frequency according to the corresponding full-band amplitude to generate first target data; if the excitation frequency is smaller than or equal to the preset frequency, extracting a plurality of low-order harmonic amplitudes and a plurality of high-order harmonic amplitudes of the frequency according to the corresponding full-band amplitude to generate second target data; and performing constraint inversion based on all the first target data and all the second target data to determine an inversion profile of the target layer, and extracting weak information of the target layer according to the inversion profile. According to the scheme, the precision of data processing and interpretation of the controllable source electromagnetic method is improved.

The invention discloses a broadband harmonic type analysis and propagation path tracking method for a flexible DC power grid system, and the method comprises the following steps: determining the number and positions of DC network harmonic monitoring points according to an electrical main wiring diagram of the flexible DC power grid system, and the harmonic limit values of different types and frequencies in each DC network harmonic monitoring point; determining the sampling frequency and interval of each converter station harmonic monitoring point, and carrying out harmonic online monitoring on the DC side bus current of each converter station of the DC power grid; when a harmonic amplitude exceeding event occurs in the direct-current power grid, determining the type of the exceeding harmonic and the frequency or frequency band of the exceeding harmonic needing to be tracked, and issuing a monitoring instruction to all monitoring points; and according to the amplitude relation of the harmonic waves needing to be tracked by each harmonic wave monitoring point in the same time period, rapid tracking of the harmonic waves in a direct current transmission network propagation path is realized by taking the frequency as the characteristic. According to the invention, rapid tracking of propagation paths of harmonic waves with different frequencies or frequency bands in the flexible DC power grid system is realized.

The invention relates to the technical field of PWM (Pulse Width Modulation), and discloses a method for optimizing double random PWM, which comprises the following steps: randomizing a carrier frequency fc and a pulse position to obtain double random PWM, performing parameter setting on random distribution of the carrier frequency and the pulse position by adopting a Sigmoid function, improving a genetic algorithm by utilizing a particle swarm algorithm, and optimizing the double random PWM. Optimizing a minimum value fmin of a random number of a carrier frequency or a pulse position, a maximum value fmax of the random number of the carrier frequency or the pulse position and a curve transverse adjustment parameter sigma of random number Sigmoid distribution in the double random PWM by adopting an improved genetic particle swarm algorithm; according to the method, harmonic energy is dispersed from frequency and phase dimensions to a wider range through double random PWM, the switching frequency and the harmonic amplitude at the integral multiple of the switching frequency are reduced, random numbers are distributed in a Sigmoid mode, and the carrier frequency and the pulse position can more easily avoid a sensitive area by means of the nonlinear probability density characteristic that samples are more on the two sides and less in the middle, so that the switching efficiency is improved. And EMI peaks caused by extreme parameters in traditional uniform distribution are reduced.

The invention provides an electric shock fault detection method and device, equipment, a storage medium and a program product. The method comprises the following steps: acquiring residual current and repeated grounding point current of the low-voltage power distribution network in a first measurement period; extracting a first harmonic amplitude of the residual current and a second harmonic amplitude of the repeated grounding point current; determining a transformation ratio according to the first harmonic amplitude, the second harmonic amplitude, a third harmonic amplitude corresponding to the residual current in the second measurement period and a fourth harmonic amplitude corresponding to the repeated grounding point current in the second measurement period; the second measurement period is a previous measurement period of the first measurement period; and detecting whether the low-voltage distribution network has an electric shock fault according to the transformation ratio. The method is used for achieving the effect of improving the electric shock fault detection reliability.

The invention discloses a distributed coupling harmonic wave cooperative positioning platform based on federated learning, relates to the technical field of power grid harmonic wave analysis, and solves the technical problems that harmonic wave data is uploaded in a concentrated manner, data leakage risks exist, the spatial dependency relationship of harmonic wave propagation between dynamic analysis nodes of a power grid topological structure is ignored, and the harmonic wave cooperative positioning accuracy is influenced. The connection relation between the nodes in the power grid topological structure can be quantified through the adjacency matrix, the observability contribution degree of each detection node to the whole network state can be accurately calculated in combination with the harmonic propagation model, measurement distribution points are optimized, and the positioning precision is improved. Gradient parameters are encrypted through a Paillier algorithm and then uploaded to a server, the server directly completes aggregation operation in a ciphertext domain, a global model can be updated without decryption, and node groups influenced by the same harmonic source are identified by calculating Spearman rank correlation coefficients of inter-node harmonic amplitudes and quantifying time synchronization degrees of different node harmonic signals.

The invention discloses a malignant load identification method suitable for an electric energy meter and an acquisition terminal, the electric energy meter and the acquisition terminal, and belongs to the technical field of load identification. The method comprises the steps that a target malignant load set is established, current data of the target malignant load set are collected, and after frequency domain features are extracted, a reference frequency domain combination feature vector of each load is constructed; obtaining target working condition current data in actual operation, and constructing a to-be-identified frequency domain combination feature vector in the same mode; and judging whether a malignant load exists or not by calculating the cosine similarity of the included angle between the two vectors. The invention also discloses an electric energy meter and a use and acquisition terminal based on the method. According to the method, the amplitude of the harmonic waves and the phase information are synthesized to construct the combined feature vector and perform similarity matching, so that the limitation that the prior art only depends on the amplitude of the harmonic waves is overcome, finer and more reliable identification of the malignant load is realized, and the misjudgment rate is effectively reduced.

The invention discloses a non-intrusive load identification method, medium and equipment, and the method is based on the improved U-I track and multi-main-body feature fusion, and specifically comprises the steps: employing a K-means clustering method of an initial optimization clustering center for the first-stage identification, carrying out the similar clustering of the obtained active power data when the user state changes, and obtaining a clustering result; therefore, the load with large difference is preliminarily identified. The second-stage identification comprises the steps of extracting load data, constructing an improved U-I track matrix fused with third-order, fifth-order, seventh-order and ninth-order current harmonic amplitudes, establishing batch normalization models, performing normalization processing on the data features of the multi-state electric equipment which cannot be accurately identified in the previous step, and obtaining a normalized data feature of the multi-state electric equipment; therefore, the power consumption data contained in different modes of the same power consumption device better conforms to the feature extraction model. And further establishing a multi-subject feature fusion model to extract clustered feature information. And finally, introducing a multi-head attention mechanism model, calculating the importance of the load characteristics, and screening out important characteristics on the basis of the importance of the load characteristics.

The invention discloses a micromechanical gyroscope driving modal vibration control method, system and device, which are applied to the field of gyroscopes, and the method comprises the following steps: obtaining two paths of differential vibration displacement electric signals; performing odd-even filtering separation processing on the two paths of differential vibration displacement electric signals by using a harmonic separator to respectively obtain odd wave vibration displacement electric signals and even wave vibration displacement electric signals; demodulating the odd wave vibration displacement electric signal by using a fundamental wave to obtain a fundamental wave amplitude, and demodulating the even wave vibration displacement electric signal by using a second harmonic to obtain a second harmonic amplitude; the quotient obtained by dividing the second harmonic amplitude by the fundamental wave amplitude is used as the second harmonic fundamental wave amplitude ratio; and generating an excitation signal according to the second harmonic fundamental wave amplitude ratio and a reference amplitude value, and outputting the excitation signal to an excitation electrode of the micromechanical gyroscope. According to the invention, the excitation signal is generated according to the fundamental wave amplitude and the second harmonic amplitude, the demodulation error is reduced, the external interference is reduced, and the closed-loop control precision is improved.

The invention discloses a fault detection method and system for a permanent magnet synchronous motor, and relates to the technical field of permanent magnet synchronous motor fault detection.The method comprises the steps that stator three-phase current during operation of the permanent magnet synchronous motor is collected in real time, and zero-sequence current is calculated; carrying out multi-band frequency spectrum analysis based on the zero sequence current, respectively detecting a third harmonic amplitude and a sixth harmonic amplitude by adopting a parallel dual-channel FFT (Fast Fourier Transform) processor, and calculating a harmonic amplitude ratio; correcting the third harmonic amplitude and the sixth harmonic amplitude through a preset compensation coefficient matrix, and recalculating the corrected harmonic amplitude ratio; and performing fault classification on the corrected harmonic amplitude ratio based on a preset threshold value in combination with a time accumulation counter, and outputting a final fault code after continuous three times of consistent detection, thereby completing fault detection of the permanent magnet synchronous motor. The fault type can be rapidly positioned, the fault diagnosis precision is improved, it is ensured that an alarm is given after real faults are accumulated to the confirmable level, and the diagnosis reliability and stability are improved.

The invention discloses a phase-control multi-channel nonlinear ultrasonic nondestructive testing system and method based on phase reversal excitation, and the method comprises the steps: generating multi-channel phase reversal waveform data and a control instruction by an upper computer, carrying out the nonlinear parameter extraction of a received digital signal, and calculating a nondestructive testing result; the phase-control high-energy fundamental frequency ultrasonic excitation module suppresses a fundamental frequency signal for the electric signal with the phase reversal waveform, enhances the harmonic amplitude, and performs delay excitation to realize fixed-point focusing; the transmitting transducer array and the receiving transducer array convert the electric signal and the acoustic signal; the multi-path double-band-pass filter is used for carrying out fundamental wave suppression, harmonic wave enhancement and clutter filtering to enhance a nonlinear effect and improve a signal-to-noise ratio; and the phase-controlled ultrasonic acquisition module is used for filtering, amplifying and sampling the multi-channel feedback electric signal and converting the multi-channel feedback electric signal into a digital signal. The method has the multi-channel nonlinear ultrasonic evaluation capability, can realize multi-channel phase reversal waveform excitation, has the ultrasonic fixed-point focusing capability, and remarkably improves the nonlinear effect detection result, so that the detection result is more accurate.

The application discloses an electromagnetic detection optimized bipolar SHMPWM transmitting method, which comprises the following steps: S1, by analyzing the influence of the resistive and inductive load on the transmitting current waveform distortion and the transmitting spectrum energy loss, extending the current waveform based on the equal-area principle, compensating for the lost transmitting current spectrum energy, and calculating the current waveform extension time; S2, considering the inductive load and the dead zone effect, establishing a bipolar SHMPWM nonlinear equation set; S3, using the particle swarm algorithm to iteratively operate the bipolar SHMPWM nonlinear equation set, and obtaining the solving result of the switching angle of the half-cycle symmetric SHMPWM. The application adopts the optimized particle swarm algorithm to solve the equation set to obtain the switching angle, and realizes that the frequency domain information of the half-cycle symmetric SHMPWM frequency focusing waveform conforms to the specific harmonic amplitude set by the expectation.

The application discloses a permanent magnet synchronous motor position estimation method based on secondary harmonic tracking. When the permanent magnet synchronous motor is in zero speed and low speed state, a high-frequency sinusoidal pulse voltage signal is injected into the estimated d-axis of the motor. The secondary harmonic current response signal is extracted, and the amplitude thereof is obtained through heterodyne and low-pass filtering processing. The system is converged to the minimum point of the current secondary harmonic amplitude through the minimum value gradient tracking method, so that the effective detection of the zero speed and low speed position of the permanent magnet synchronous motor is realized. The application can realize the unique position convergence point in the whole error range, so as to improve the estimation performance and robustness of the system in the zero speed and low speed interval.

The invention discloses an automobile aluminum alloy plate detection method, and relates to the technical field of metal plate detection, and the method comprises the steps: 1, collecting the thickness of an aluminum alloy plate; 2, the value range of detection parameters is adjusted through a detector according to the thickness of the aluminum alloy plate, and the detection parameters comprise the incident excitation frequency, the incident angle, the receiving angle and the distance between the incident end and the receiving end; and 3, the fundamental wave amplitude, the second harmonic amplitude and the relation between the relative second-order nonlinear coefficient distribution and the fatigue cycle number of the excited Lamb waves are obtained, the aluminum alloy plates are detected, and the time when fatigue cracks appear on the aluminum alloy plates with different thicknesses is judged. The method has the characteristic of more accurate detection.

The application discloses a three-level inverter harmonic suppression method based on zero vector symmetrical reconstruction and spread spectrum composite modulation, and the method comprises the following steps: step 1, signal acquisition and voltage instruction acquisition; step 2, spread spectrum modulation parameter setting; step 3, basic vector action time calculation; step 4, zero vector symmetrical reconstruction of vector sequence; step 5, switch time calculation and register updating; and step 6, PWM signal generation and system closed loop operation. The application realizes full-band suppression of inverter output PWM harmonics by deeply fusing the zero vector symmetrical reconstruction technology and the spread spectrum modulation technology. The application can be applied to a permanent magnet synchronous motor driving system powered by a three-level voltage source inverter, can simultaneously suppress the PWM harmonic amplitude near the odd carrier frequency and the even carrier frequency, effectively reduces electromagnetic vibration and noise, and has extremely high application value in the field of high-power inverters and motor drives.

The embodiment of the application provides a kind of wide frequency signal dynamic generation method and system based on multiple clock sources, the method comprises: by field programmable gate array real-time monitoring target frequency, and based on the frequency band of target frequency belongs to automatically switched to corresponding target clock source;When the target clock source is switched, the phase difference corresponding to the new and old target clock source is corrected by phase compensation register, and the compensation value is loaded to the phase offset register of direct digital frequency synthesis chip;Based on direct digital frequency synthesis chip, generate the fundamental wave waveform of wide frequency signal, and superimpose multiple harmonic components by sub-accumulation method, and the amplitude of each harmonic is independently controlled by look-up table method;The output signal of power amplifier is extracted by analog-digital converter, and the error information of measured waveform and theoretical waveform is extracted and dynamically corrected phase offset register and harmonic amplitude look-up table coefficient, and output target wide frequency signal.The application realizes the unity of wide frequency coverage, high resolution and fast response.

The application relates to the technical field of power conversion device control, and discloses a power distribution network power conversion equipment harmonic suppression method and system. The method comprises the following steps: collecting harmonic amplitudes to construct a state vector and a coupling matrix, predicting the control harmonic and calculating a feedback influence quantity, superimposing an inhibition quantity and a compensation quantity to generate a double-layer instruction to adjust a switching parameter, outputting a pulse width modulation signal and monitoring a residual error to update the coupling matrix. The application improves the global optimization performance of harmonic suppression and the self-adaptive ability to power grid environment changes.

The present application provides a real-time optimization method, system and device for inverter output voltage harmonics, the method comprising: obtaining control parameters of an inverter; controlling the inverter to work according to the control parameters and obtaining N waveforms corresponding to N periods; decomposing the N waveforms to determine a to-be-processed waveform harmonic; when the amplitude of the to-be-processed waveform harmonic exceeds a harmonic threshold, a first optimization mode is used for optimization processing; when the amplitude of the to-be-processed waveform harmonic does not exceed the harmonic threshold, a second optimization mode is used for optimization processing. A method combining two harmonic reduction technologies is used, when the harmonic amplitude is small, the active filter function of the auxiliary inverter is used to reduce the harmonic, and the SHEPWM complex calculation is not used, when the harmonic amplitude is large, the SHEPWM technology is used to eliminate the harmonic, and the flexibility of inverter control is improved.